Using full-cohort data in nested case-control and case-cohort studies by multiple imputation.

PubMed

Keogh, Ruth H; White, Ian R

2013-10-15

In many large prospective cohorts, expensive exposure measurements cannot be obtained for all individuals. Exposure-disease association studies are therefore often based on nested case-control or case-cohort studies in which complete information is obtained only for sampled individuals. However, in the full cohort, there may be a large amount of information on cheaply available covariates and possibly a surrogate of the main exposure(s), which typically goes unused. We view the nested case-control or case-cohort study plus the remainder of the cohort as a full-cohort study with missing data. Hence, we propose using multiple imputation (MI) to utilise information in the full cohort when data from the sub-studies are analysed. We use the fully observed data to fit the imputation models. We consider using approximate imputation models and also using rejection sampling to draw imputed values from the true distribution of the missing values given the observed data. Simulation studies show that using MI to utilise full-cohort information in the analysis of nested case-control and case-cohort studies can result in important gains in efficiency, particularly when a surrogate of the main exposure is available in the full cohort. In simulations, this method outperforms counter-matching in nested case-control studies and a weighted analysis for case-cohort studies, both of which use some full-cohort information. Approximate imputation models perform well except when there are interactions or non-linear terms in the outcome model, where imputation using rejection sampling works well. Copyright © 2013 John Wiley & Sons, Ltd.

Integration of Traditional and E-Learning Methods to Improve Learning Outcomes for Dental Students in Histopathology.

PubMed

Ariana, Armin; Amin, Moein; Pakneshan, Sahar; Dolan-Evans, Elliot; Lam, Alfred K

2016-09-01

Dental students require a basic ability to explain and apply general principles of pathology to systemic, dental, and oral pathology. Although there have been recent advances in electronic and online resources, the academic effectiveness of using self-directed e-learning tools in pathology courses for dental students is unclear. The aim of this study was to determine if blended learning combining e-learning with traditional learning methods of lectures and tutorials would improve students' scores and satisfaction over those who experienced traditional learning alone. Two consecutive cohorts of Bachelor of Dentistry and Oral Health students taking the general pathology course at Griffith University in Australia were compared. The control cohort experienced traditional methods only, while members of the study cohort were also offered self-directed learning materials including online resources and online microscopy classes. Final assessments for the course were used to compare the differences in effectiveness of the intervention, and students' satisfaction with the teaching format was evaluated using questionnaires. On the final course assessments, students in the study cohort had significantly higher scores than students in the control cohort (p<0.01). Analysis of questionnaire results showed improved student satisfaction with the course in the study cohort. These findings suggest that the use of e-learning tools such as virtual microscopy and interactive online resources for delivering pathology instruction can be an effective supplement for developing dental students' competence, confidence, and satisfaction.

Case-Cohort Studies: Design and Applicability to Hand Surgery.

PubMed

Vojvodic, Miliana; Shafarenko, Mark; McCabe, Steven J

2018-04-24

Observational studies are common research strategies in hand surgery. The case-cohort design offers an efficient and resource-friendly method for risk assessment and outcomes analysis. Case-cohorts remain underrepresented in upper extremity research despite several practical and economic advantages over case-control studies. This report outlines the purpose, utility, and structure of the case-cohort design and offers a sample research question to demonstrate its value to risk estimation for adverse surgical outcomes. The application of well-designed case-cohort studies is advocated in an effort to improve the quality and quantity of observational research evidence in hand and upper extremity surgery. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Performance of the disease risk score in a cohort study with policy-induced selection bias.

PubMed

Tadrous, Mina; Mamdani, Muhammad M; Juurlink, David N; Krahn, Murray D; Lévesque, Linda E; Cadarette, Suzanne M

2015-11-01

To examine the performance of the disease risk score (DRS) in a cohort study with evidence of policy-induced selection bias. We examined two cohorts of new users of bisphosphonates. Estimates for 1-year hip fracture rates between agents using DRS, exposure propensity scores and traditional multivariable analysis were compared. The results for the cohort with no evidence of policy-induced selection bias showed little variation across analyses (-4.1-2.0%). Analysis of the cohort with evidence of policy-induced selection bias showed greater variation (-13.5-8.1%), with the greatest difference seen with DRS analyses. Our findings suggest that caution may be warranted when using DRS methods in cohort studies with policy-induced selection bias, further research is needed.

How to Establish and Follow up a Large Prospective Cohort Study in the 21st Century--Lessons from UK COSMOS.

PubMed

Toledano, Mireille B; Smith, Rachel B; Brook, James P; Douglass, Margaret; Elliott, Paul

2015-01-01

Large-scale prospective cohort studies are invaluable in epidemiology, but they are increasingly difficult and costly to establish and follow-up. More efficient methods for recruitment, data collection and follow-up are essential if such studies are to remain feasible with limited public and research funds. Here, we discuss how these challenges were addressed in the UK COSMOS cohort study where fixed budget and limited time frame necessitated new approaches to consent and recruitment between 2009-2012. Web-based e-consent and data collection should be considered in large scale observational studies, as they offer a streamlined experience which benefits both participants and researchers and save costs. Commercial providers of register and marketing data, smartphones, apps, email, social media, and the internet offer innovative possibilities for identifying, recruiting and following up cohorts. Using examples from UK COSMOS, this article sets out the dos and don'ts for today's cohort studies and provides a guide on how best to take advantage of new technologies and innovative methods to simplify logistics and minimise costs. Thus a more streamlined experience to the benefit of both research participants and researchers becomes achievable.

How to Establish and Follow up a Large Prospective Cohort Study in the 21st Century - Lessons from UK COSMOS

PubMed Central

Toledano, Mireille B.; Smith, Rachel B.; Brook, James P.; Douglass, Margaret; Elliott, Paul

2015-01-01

Large-scale prospective cohort studies are invaluable in epidemiology, but they are increasingly difficult and costly to establish and follow-up. More efficient methods for recruitment, data collection and follow-up are essential if such studies are to remain feasible with limited public and research funds. Here, we discuss how these challenges were addressed in the UK COSMOS cohort study where fixed budget and limited time frame necessitated new approaches to consent and recruitment between 2009-2012. Web-based e-consent and data collection should be considered in large scale observational studies, as they offer a streamlined experience which benefits both participants and researchers and save costs. Commercial providers of register and marketing data, smartphones, apps, email, social media, and the internet offer innovative possibilities for identifying, recruiting and following up cohorts. Using examples from UK COSMOS, this article sets out the dos and don’ts for today's cohort studies and provides a guide on how best to take advantage of new technologies and innovative methods to simplify logistics and minimise costs. Thus a more streamlined experience to the benefit of both research participants and researchers becomes achievable. PMID:26147611

Evaluation of team-based learning in a doctor of physical therapy curriculum in the United States.

PubMed

Lein, Donald H; Lowman, John D; Eidson, Christopher A; Yuen, Hon K

2017-01-01

The purpose of this retrospective study was to evaluate students' academic outcomes after implementation of the team-based learning (TBL) approach in patient/client management courses in an entry-level doctor of physical therapy (DPT) curriculum. The research design of this study involved comparing written and practical exam scores from DPT student cohorts taught with the traditional instructional methods (lecture-based) to those of students from subsequent cohorts taught using the TBL approach in two patient/client management courses: basic skills and cardiopulmonary. For this comparison, the exams used, the number of contact hours and labs, and the instructors who taught these courses remained the same during the transition between these two instructional methods (traditional vs. TBL). The average of all individual course exam scores was used for data analysis. In both courses, there were no meaningful differences in the mean exam scores among students across years of cohorts receiving the same instructional method, which allowed clustering students from different years of cohorts in each course receiving the same instructional method into one group. For both courses, the mean exam score was significantly higher in the TBL group than in the traditional instruction group: basic skills course (P<0.001) and cardiopulmonary course (P<0.001). Student cohorts taught using the TBL approach academically outperformed those who received the traditional instructional method in both entry-level DPT patient/client management courses.

Analysis of cohort studies with multivariate and partially observed disease classification data.

PubMed

Chatterjee, Nilanjan; Sinha, Samiran; Diver, W Ryan; Feigelson, Heather Spencer

2010-09-01

Complex diseases like cancers can often be classified into subtypes using various pathological and molecular traits of the disease. In this article, we develop methods for analysis of disease incidence in cohort studies incorporating data on multiple disease traits using a two-stage semiparametric Cox proportional hazards regression model that allows one to examine the heterogeneity in the effect of the covariates by the levels of the different disease traits. For inference in the presence of missing disease traits, we propose a generalization of an estimating equation approach for handling missing cause of failure in competing-risk data. We prove asymptotic unbiasedness of the estimating equation method under a general missing-at-random assumption and propose a novel influence-function-based sandwich variance estimator. The methods are illustrated using simulation studies and a real data application involving the Cancer Prevention Study II nutrition cohort.

Situating Computer Simulation Professional Development: Does It Promote Inquiry-Based Simulation Use?

ERIC Educational Resources Information Center

Gonczi, Amanda L.; Maeng, Jennifer L.; Bell, Randy L.; Whitworth, Brooke A.

2016-01-01

This mixed-methods study sought to identify professional development implementation variables that may influence participant (a) adoption of simulations, and (b) use for inquiry-based science instruction. Two groups (Cohort 1, N = 52; Cohort 2, N = 104) received different professional development. Cohort 1 was focused on Web site use mechanics.…

Dental Students' Perceived Clinical Competence in Prosthodontics: Comparison of Traditional and Problem-Based Learning Methodologies.

PubMed

Montero, Javier; Dib, Abraham; Guadilla, Yasmina; Flores, Javier; Santos, Juan Antonio; Aguilar, Rosa Anaya; Gómez-Polo, Cristina

2018-02-01

The aim of this study was to compare the perceived competence for treating prosthodontic patients of two samples of fourth-year dental students: those educated using traditional methodologies and those educated using problem-based learning (PBL). Two cohorts of fourth-year dental students at a dental school in Spain were surveyed: the traditional methods cohort (n=46) was comprised of all students in academic years 2012 and 2013, and the PBL cohort (n=57) was comprised of all students in academic years 2014 and 2015. Students in both cohorts reported the number of prosthodontic treatments they carried out per year and their perceived level of competence in performing such treatments. The results showed that the average number of treatments performed was similar for the two cohorts, except the number of metal-based removable partial dentures was significantly higher for students in the traditional (0.8±1.0) than the PBL (0.4±0.6) cohort. The level of perceived competence to treat complete denture patients for the combined cohorts was significantly higher (7.3±1.1) than that for partial acrylic dentures (6.7±1.5) and combined dentures (5.7±1.3). Students' clinical competence in prosthodontics mainly depended on number of treatments performed as the operator as well as the assistant. Students in the traditional methods cohort considered themselves to be significantly more competent at treating patients for removable partial and fixed prostheses (7.8±1.1 and 7.6±1.1, respectively) than did students in the PBL cohort (6.4±1.5 and 6.6±1.5, respectively). Overall, however, the study found that practical experiences were more important than the teaching method used to achieve students' perceived competence.

A Study of Psychological Distress in Two Cohorts of First-Year Medical Students that Underwent Different Admission Selection Processes

PubMed Central

Yusoff, Muhamad Saiful Bahri; Rahim, Ahmad Fuad Abdul; Baba, Abdul Aziz; Ismail, Shaiful Bahari; Esa, Ab Rahman

2012-01-01

Background: Medical training is often regarded as a stressful period. Studies have previously found that 21.6%–50% of medical students experience significant psychological distress. The present study compared the prevalence and levels of psychological distress between 2 cohorts of first-year medical students that underwent different admission selection processes. Methods: A comparative cross-sectional study was conducted by comparing 2 cohorts of first-year medical students; 1 group (cohort 1) was selected based purely on academic merit (2008/2009 cohort) and the other group (cohort 2) was selected based on academic merit, psychometric assessment, and interview performance (2009/2010 cohort). Their distress levels were measured by the General Health Questionnaire, and scores higher than 3 were considered indicative of significant psychological distress. Results: The prevalence (P = 0.003) and levels (P = 0.001) of psychological distress were significantly different between the 2 cohorts. Cohort 1 had 1.2–3.3 times higher risk of developing psychological distress compared to cohort 2 (P = 0.007). Conclusion: Cohort 2 had better psychological health than cohort 1 and was less likely to develop psychological distress. This study provided evidence of a potential benefit of multimodal student selection based on academic merit, psychometric assessment, and interview performance. This selection process might identify medical students who will maintain better psychological health. PMID:23610547

Global teaching and training initiatives for emerging cohort studies

PubMed Central

Paulus, Jessica K.; Santoyo-Vistrain, Rocío; Havelick, David; Cohen, Amy; Kalyesubula, Robert; Ajayi, Ikeoluwapo O.; Mattsson, Jens G.; Adami, Hans-Olov; Dalal, Shona

2015-01-01

A striking disparity exists across the globe, with essentially no large-scale longitudinal studies ongoing in regions that will be significantly affected by the oncoming non-communicable disease epidemic. The successful implementation of cohort studies in most low-resource research environments presents unique challenges that may be aided by coordinated training programs. Leaders of emerging cohort studies attending the First World Cohort Integration Workshop were surveyed about training priorities, unmet needs and potential cross-cohort solutions to these barriers through an electronic pre-workshop questionnaire and focus groups. Cohort studies representing India, Mexico, Nigeria, South Africa, Sweden, Tanzania and Uganda described similar training needs, including on-the-job training, data analysis software instruction, and database and bio-bank management. A lack of funding and protected time for training activities were commonly identified constraints. Proposed solutions include a collaborative cross-cohort teaching platform with web-based content and interactive teaching methods for a range of research personnel. An international network for research mentorship and idea exchange, and modifying the graduate thesis structure were also identified as key initiatives. Cross-cohort integrated educational initiatives will efficiently meet shared needs, catalyze the development of emerging cohorts, speed closure of the global disparity in cohort research, and may fortify scientific capacity development in low-resource settings. PMID:23856451

Inter-cohort growth for three tropical resources: tilapia, octopus and lobster.

PubMed

Velázquez-Abunader, Iván; Gómez-Muñoz, Victor Manuel; Salas, Silvia; Ruiz-Velazco, Javier M J

2015-09-01

Growth parameters are an important component for the stock assessment of exploited aquatic species. However, it is often difficult to apply direct methods to estimate growth and to analyse the differences between males and females, particularly in tropical areas. The objective of this study was to analyse the inter-cohort growth of three tropical resources and discuss the possible fisheries management implications. A simple method was used to compare individual growth curves obtained from length frequency distribution analysis, illustrated by case studies of three tropical species from different aquatic environments: tilapia (Oreochromis aureus), red octopus (Octopus maya) and the Caribbean spiny lobster (Panulirus argus). The analysis undertaken compared the size distribution of males and females of a given cohort through modal progression analysis. The technique used proved to be useful for highlighting the differences in growth between females and males of a specific cohort. The potential effect of extrinsic and intrinsic factors on the organism's development as reflected in the size distribution of the cohorts is discussed.

Improved Horvitz-Thompson Estimation of Model Parameters from Two-phase Stratified Samples: Applications in Epidemiology

PubMed Central

Breslow, Norman E.; Lumley, Thomas; Ballantyne, Christie M; Chambless, Lloyd E.; Kulich, Michal

2009-01-01

The case-cohort study involves two-phase sampling: simple random sampling from an infinite super-population at phase one and stratified random sampling from a finite cohort at phase two. Standard analyses of case-cohort data involve solution of inverse probability weighted (IPW) estimating equations, with weights determined by the known phase two sampling fractions. The variance of parameter estimates in (semi)parametric models, including the Cox model, is the sum of two terms: (i) the model based variance of the usual estimates that would be calculated if full data were available for the entire cohort; and (ii) the design based variance from IPW estimation of the unknown cohort total of the efficient influence function (IF) contributions. This second variance component may be reduced by adjusting the sampling weights, either by calibration to known cohort totals of auxiliary variables correlated with the IF contributions or by their estimation using these same auxiliary variables. Both adjustment methods are implemented in the R survey package. We derive the limit laws of coefficients estimated using adjusted weights. The asymptotic results suggest practical methods for construction of auxiliary variables that are evaluated by simulation of case-cohort samples from the National Wilms Tumor Study and by log-linear modeling of case-cohort data from the Atherosclerosis Risk in Communities Study. Although not semiparametric efficient, estimators based on adjusted weights may come close to achieving full efficiency within the class of augmented IPW estimators. PMID:20174455

Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe

PubMed Central

Travison, Thomas G.; Vesper, Hubert W.; Orwoll, Eric; Wu, Frederick; Kaufman, Jean Marc; Wang, Ying; Lapauw, Bruno; Fiers, Tom; Matsumoto, Alvin M.

2017-01-01

Background: Reference ranges for testosterone are essential for making a diagnosis of hypogonadism in men. Objective: To establish harmonized reference ranges for total testosterone in men that can be applied across laboratories by cross-calibrating assays to a reference method and standard. Population: The 9054 community-dwelling men in cohort studies in the United States and Europe: Framingham Heart Study; European Male Aging Study; Osteoporotic Fractures in Men Study; and Male Sibling Study of Osteoporosis. Methods: Testosterone concentrations in 100 participants in each of the four cohorts were measured using a reference method at Centers for Disease Control and Prevention (CDC). Generalized additive models and Bland-Altman analyses supported the use of normalizing equations for transformation between cohort-specific and CDC values. Normalizing equations, generated using Passing-Bablok regression, were used to generate harmonized values, which were used to derive standardized, age-specific reference ranges. Results: Harmonization procedure reduced intercohort variation between testosterone measurements in men of similar ages. In healthy nonobese men, 19 to 39 years, harmonized 2.5th, 5th, 50th, 95th, and 97.5th percentile values were 264, 303, 531, 852, and 916 ng/dL, respectively. Age-specific harmonized testosterone concentrations in nonobese men were similar across cohorts and greater than in all men. Conclusion: Harmonized normal range in a healthy nonobese population of European and American men, 19 to 39 years, is 264 to 916 ng/dL. A substantial proportion of intercohort variation in testosterone levels is due to assay differences. These data demonstrate the feasibility of generating harmonized reference ranges for testosterone that can be applied to assays, which have been calibrated to a reference method and calibrator. PMID:28324103

Feasibility of reusing time-matched controls in an overlapping cohort.

PubMed

Delcoigne, Bénédicte; Hagenbuch, Niels; Schelin, Maria Ec; Salim, Agus; Lindström, Linda S; Bergh, Jonas; Czene, Kamila; Reilly, Marie

2018-06-01

The methods developed for secondary analysis of nested case-control data have been illustrated only in simplified settings in a common cohort and have not found their way into biostatistical practice. This paper demonstrates the feasibility of reusing prior nested case-control data in a realistic setting where a new outcome is available in an overlapping cohort where no new controls were gathered and where all data have been anonymised. Using basic information about the background cohort and sampling criteria, the new cases and prior data are "aligned" to identify the common underlying study base. With this study base, a Kaplan-Meier table of the prior outcome extracts the risk sets required to calculate the weights to assign to the controls to remove the sampling bias. A weighted Cox regression, implemented in standard statistical software, provides unbiased hazard ratios. Using the method to compare cases of contralateral breast cancer to available controls from a prior study of metastases, we identified a multifocal tumor as a risk factor that has not been reported previously. We examine the sensitivity of the method to an imperfect weighting scheme and discuss its merits and pitfalls to provide guidance for its use in medical research studies.

A clinical research analytics toolkit for cohort study.

PubMed

Yu, Yiqin; Zhu, Yu; Sun, Xingzhi; Tao, Ying; Zhang, Shuo; Xu, Linhao; Pan, Yue

2012-01-01

This paper presents a clinical informatics toolkit that can assist physicians to conduct cohort studies effectively and efficiently. The toolkit has three key features: 1) support of procedures defined in epidemiology, 2) recommendation of statistical methods in data analysis, and 3) automatic generation of research reports. On one hand, our system can help physicians control research quality by leveraging the integrated knowledge of epidemiology and medical statistics; on the other hand, it can improve productivity by reducing the complexities for physicians during their cohort studies.

Obesity and Associated Adverse Health Outcomes Among U.S. Military Members and Veterans: Findings from the Millennium Cohort Study

DTIC Science & Technology

2016-06-27

Obesity and Associated Adverse Health Outcomes Among US Military Members and Veterans: Findings from the Millennium Cohort Study Toni Rush1,2,3...Cynthia A. LeardMann3, and Nancy F. Crum-Cianflone1,3,4 Objective: To assess the prevalence of obesity and associated health outcomes among US service...members and veterans. Methods: Data from three survey cycles (2001–2008) of the Millennium Cohort Study were used to examine the prevalence of obesity

Design and conduct of an internet-based preconception cohort study in North America: Pregnancy Study Online (PRESTO)

PubMed Central

Wise, Lauren A; Rothman, Kenneth J.; Mikkelsen, Ellen M.; Stanford, Joseph B.; Wesselink, Amelia K.; McKinnon, Craig; Gruschow, Siobhan M.; Horgan, Casie E.; Wiley, Aleta S.; Hahn, Kristen A.; Sørensen, Henrik Toft; Hatch, Elizabeth E.

2015-01-01

Background We launched the Boston University Pregnancy Study Online (PRESTO) to assess the feasibility of carrying out an internet-based preconception cohort study in the U.S. and Canada. Methods We recruited female participants age 21–45 and their male partners through internet advertisements, word of mouth, and flyers. Female participants were randomized with 50% probability to receive a subscription to FertilityFriend.com (FF), a web-based program that collects real-time data on menstrual characteristics. We compared recruitment methods within PRESTO, assessed the cost-efficiency of PRESTO relative to its Danish counterpart (Snart-Gravid), and validated retrospectively-reported date of last menstrual period (LMP) against FF data. Results After 99 weeks of recruitment (2013–2015), 2,421 women enrolled; 1,384 (57%) invited their male partners to participate, of whom 693 (50%) enrolled. Baseline characteristics were balanced across randomization groups. Cohort retention was similar among those randomized vs. not randomized to FF (84% vs. 81%). At study enrollment, 56%, 22%, and 22% couples had been trying to conceive for <3, 3–5, and ≥6 months, respectively. The cost per subject enrolled was $146 (2013 $US), which was similar to our companion Danish study and half that of a traditional cohort study. Among FF users who conceived, >97% reported their LMP on the PRESTO questionnaire within 1 day of the LMP recorded via FF. Conclusions Use of the internet as a method of recruitment and follow-up in a North American preconception cohort study was feasible and cost-effective. PMID:26111445

Evaluation of Planned Treatment Breaks During Radiation Therapy for Anal Cancer: Update of RTOG 92-08

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konski, Andre; Garcia, Miguel; John, Madhu

2008-09-01

Purpose: Radiation Therapy Oncology Group (RTOG) 92-08 began as a single arm, Phase II trial for patients with anal cancer consisting of radiation (RT) + 5-flourouracil + mitomycin-C with a mandatory 2-week break and was amended after completion to evaluate the same treatment regimen without a treatment break. Long-term efficacy and late toxicity reporting are the specific aims of this study. Methods and Materials: Survivals were estimated with the Kaplan-Meier method. Overall survival (OS) was compared with RTOG 87-04 with the log-rank test. Time to local failure, regional failure, locoregional failure (LRF), distant metastases, second primary, and colostomy failure weremore » estimated by the cumulative incidence method. LRF was compared with RTOG 87-04 using the Gray's test. Results: Forty-seven patients entered in the mandatory treatment break cohort. The study was reopened in 1995 to the no mandatory treatment break cohort completing accrual with 20 patients in 1996. Of 67 total patients, 1 patient in the mandatory treatment break portion of the study did not receive any protocol treatment and is excluded from analyses. After adjusting for tumor size, neither cohort showed a statistically significant difference in OS or LRF compared with the RTOG 87-04 mitomycin-C arm. No patient in either cohort experienced a Grade 3 or higher late toxicity. Conclusions: No statistically significant differences were seen in OS or LRF when compared to the mitomycin-C arm of RTOG 87-04, but the sample sizes for the mandatory break cohort and the no mandatory break cohort are small. Late toxicity was low and similar for the treatment cohorts.« less

Developmental dysplasia of the hip: impact of sonographic newborn hip screening on the outcome of early treated decentered hip joints-a single center retrospective comparative cohort study based on Graf's method of hip ultrasonography.

PubMed

Tschauner, Christian; Fürntrath, Frank; Saba, Yasaman; Berghold, Andrea; Radl, Roman

2011-12-01

PURPOSE/BACKGROUND/INTRODUCTION: The aim of this study was to retrospectively evaluate the impact of neonatal sonographic hip screening using Graf's method for the management and outcome of orthopaedic treatment of decentered hip joints with developmental dysplasia of the hip (DDH), using three decades (1978-2007) of clinical information compiled in a medical database. Three representative cohorts of consecutive cases of decentered hip joints were selected according to different search criteria and inclusion and exclusion parameters: (1) cohort 1 (1978-1982; n = 80), without sonographic screening; (2) cohort 2.1 (1994-1996; n = 91), with nationwide established general sonographic screening according to the Graf-method; (3) cohort 2.2 (2003-2005; n = 91), with sonographic screening including referred cases for open reduction from non-screened populations. These three cohorts were compared for the following parameters: age at initial treatment, successful closed reduction, necessary overhead traction, necessary adductor-tenotomy, rate of open reduction, rate of avascular necrosis (AVN) and rate of secondary acetabuloplasty. The age at initial treatment was reduced from 5.5 months in the first cohort to 2 months in the two subsequent two cohorts and the rate of successful closed reduction increased from 88.7 to 98.9 and 95.6%, respectively. There was a statistically significant improvement in six out of seven parameters with sonographic hip screening; only the rate of secondary acetabuloplasty did not improve significantly. Compared to the era before the institution of a sonographic hip screening programme according to the Graf-method in Austria in 1992, ultrasound screening based-treatment of decentered hip joints has become safer, shorter and simpler: "safer" means lower rate of AVN, "shorter" means less treatment time due to earlier onset and "simpler" means that the devices are now less invasive and highly standardized.

Can Comprehensive Chromosome Screening Technology Improve IVF/ICSI Outcomes? A Meta-Analysis

PubMed Central

Quan, Song

2015-01-01

Objective To examine whether comprehensive chromosome screening (CCS) for preimplantation genetic screening (PGS) has an effect on improving in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes compared to traditional morphological methods. Methods A literature search was conducted in PubMed, EMBASE, CNKI and ClinicalTrials.gov up to May 2015. Two reviewers independently evaluated titles and abstracts, extracted data and assessed quality. We included studies that compared the IVF/ICSI outcomes of CCS-based embryo selection with those of the traditional morphological method. Relative risk (RR) values with corresponding 95% confidence intervals (CIs) were calculated in RevMan 5.3, and subgroup analysis and Begg’s test were used to assess heterogeneity and potential publication bias, respectively. Results Four RCTs and seven cohort studies were included. A meta-analysis of the outcomes showed that compared to morphological criteria, euploid embryos identified by CCS were more likely to be successfully implanted (RCT RR 1.32, 95% CI 1.18–1.47; cohort study RR 1.74, 95% CI 1.35–2.24). CCS-based PGS was also related to an increased clinical pregnancy rate (RCT RR 1.26, 95% CI 0.83–1.93; cohort study RR 1.48, 95% CI 1.20–1.83), an increased ongoing pregnancy rate (RCT RR 1.31, 95% CI 0.64–2.66; cohort study RR 1.61, 95% CI 1.30–2.00), and an increased live birth rate (RCT RR 1.26, 95% CI 1.05–1.50; cohort study RR 1.35, 95% CI 0.85–2.13) as well as a decreased miscarriage rate (RCT RR 0.53, 95% CI 0.24–1.15; cohort study RR 0.31, 95% CI 0.21–0.46) and a decreased multiple pregnancy rate (RCT RR 0.02, 95% CI 0.00–0.26; cohort study RR 0.19, 95% CI 0.07–0.51). The results of the subgroup analysis also showed a significantly increased implantation rate in the CCS group. Conclusions The effectiveness of CCS-based PGS is comparable to that of traditional morphological methods, with better outcomes for women receiving IVF/ICSI technology. The transfer of both trophectoderm-biopsied and blastomere-biopsied CCS-euploid embryos can improve the implantation rate. PMID:26470028

ANALYZING COHORT MORTALITY DATA

EPA Science Inventory

Several methods for analyzing data from mortality studies of occupationally or environmentally exposed cohorts are shown to be special cases of a single procedure. The procedure assumes a proportional hazards model for exposure effects and represents the log-likelihood kernel for...

Air Pollution and Nonmalignant Respiratory Mortality in 16 Cohorts within the ESCAPE Project

PubMed Central

Dimakopoulou, Konstantina; Samoli, Evangelia; Beelen, Rob; Stafoggia, Massimo; Andersen, Zorana Jovanovic; Hoffmann, Barbara; Fischer, Paul; Nieuwenhuijsen, Mark; Vineis, Paolo; Xun, Wei; Hoek, Gerard; Raaschou-Nielsen, Ole; Oudin, Anna; Forsberg, Bertil; Modig, Lars; Jousilahti, Pekka; Lanki, Timo; Turunen, Anu; Oftedal, Bente; Nafstad, Per; Schwarze, Per E.; Penell, Johanna; Fratiglioni, Laura; Andersson, Niklas; Pedersen, Nancy; Korek, Michal; De Faire, Ulf; Eriksen, Kirsten Thorup; Tjønneland, Anne; Becker, Thomas; Wang, Meng; Bueno-de-Mesquita, Bas; Tsai, Ming-Yi; Eeftens, Marloes; Peeters, Petra H.; Meliefste, Kees; Marcon, Alessandro; Krämer, Ursula; Kuhlbusch, Thomas A.J.; Vossoughi, Mohammad; Key, Timothy; de Hoogh, Kees; Hampel, Regina; Peters, Annette; Heinrich, Joachim; Weinmayr, Gudrun; Concin, Hans; Nagel, Gabriele; Ineichen, Alex; Jacquemin, Bénédicte; Stempfelet, Morgane; Vilier, Alice; Ricceri, Fulvio; Sacerdote, Carlotta; Pedeli, Xanthi; Katsoulis, Michalis; Trichopoulou, Antonia; Brunekreef, Bert

2014-01-01

Rationale: Prospective cohort studies have shown that chronic exposure to particulate matter and traffic-related air pollution is associated with reduced survival. However, the effects on nonmalignant respiratory mortality are less studied, and the data reported are less consistent. Objectives: We have investigated the relationship of long-term exposure to air pollution and nonmalignant respiratory mortality in 16 cohorts with individual level data within the multicenter European Study of Cohorts for Air Pollution Effects (ESCAPE). Methods: Data from 16 ongoing cohort studies from Europe were used. The total number of subjects was 307,553. There were 1,559 respiratory deaths during follow-up. Measurements and Main Results: Air pollution exposure was estimated by land use regression models at the baseline residential addresses of study participants and traffic-proximity variables were derived from geographical databases following a standardized procedure within the ESCAPE study. Cohort-specific hazard ratios obtained by Cox proportional hazard models from standardized individual cohort analyses were combined using metaanalyses. We found no significant associations between air pollution exposure and nonmalignant respiratory mortality. Most hazard ratios were slightly below unity, with the exception of the traffic-proximity indicators. Conclusions: In this study of 16 cohorts, there was no association between air pollution exposure and nonmalignant respiratory mortality. PMID:24521254

The Relationship between Motor Abilities and Early Social Development in a Preschool Cohort of Children with Cerebral Palsy

ERIC Educational Resources Information Center

Whittingham, Koa; Fahey, Michael; Rawicki, Barry; Boyd, Roslyn

2010-01-01

Aim: To investigate the relationship between motor ability and early social development in a cohort of preschool children with cerebral palsy (CP). Design: Population-based cohort study. Methods: Participants were 122 children with CP assessed at 18, 24 and 30 months, corrected age (ca). Motor ability was measured by the Gross Motor Function…

Cohort Differences in the Availability of Informal Caregivers: Are the Boomers at Risk?

ERIC Educational Resources Information Center

Ryan, Lindsay H.; Smith, Jacqui; Antonucci, Toni C.; Jackson, James S.

2012-01-01

Purpose of the Study: We compare the close family resources of Baby Boomers (BBs) to previous cohorts of older adults at population level and then examine individual-level cohort comparisons of age-related trajectories of informal care availability from midlife into old age. Design and Methods: Population data from the U.S. Census and from the…

South Yorkshire Cohort: a 'cohort trials facility' study of health and weight - Protocol for the recruitment phase

PubMed Central

2011-01-01

Background Growing levels of both obesity and chronic disease in the general population pose a major public health problem. In the UK, an innovative 'health and weight' cohort trials facility, the 'South Yorkshire Cohort', is being built in order to provide robust evidence to inform policy, commissioning and clinical decisions in this field. This protocol reports the design of the facility and outlines the recruitment phase methods. Method/Design The South Yorkshire Cohort health and weight study uses the cohort multiple randomised controlled trial design. This design recruits a large observational cohort of patients with the condition(s) of interest which then provides a facility for multiple randomised controlled trials (with large representative samples of participants, long term outcomes as standard, increased comparability between each trial conducted within the cohort and increased efficiency particularly for trials of expensive interventions) as well as ongoing information as to the natural history of the condition and treatment as usual. This study aims to recruit 20,000 participants to the population based South Yorkshire Cohort health and weight research trials facility. Participants are recruited by invitation letters from their General Practitioners. Data is collected using postal and/or online patient self completed Health Questionnaires. NHS numbers will be used to facilitate record linkage and access to routine data. Participants are eligible if they are: aged 16 - 85 years, registered with one of 40 practices in South Yorkshire, provide consent for further contact from the researchers and to have their information used to look at the benefit of health treatments. The first wave of data is being collected during 2010/12 and further waves are planned at 2 - 5 year intervals for the planned 20 year duration of the facility. Discussion The South Yorkshire Cohort combines the strengths of the standard observational, longitudinal cohort study design with a population based cohort facility for multiple randomised controlled trials in a range of long term health and weight related conditions (including obesity). This infrastructure will allow the rapid and cheap identification and recruitment of patients, and facilitate the provision of robust evidence to inform the management and self-management of health and weight. PMID:21834964

A survey of national and multi-national registries and cohort studies in juvenile idiopathic arthritis: challenges and opportunities.

PubMed

Beukelman, Timothy; Anink, Janneke; Berntson, Lillemor; Duffy, Ciaran; Ellis, Justine A; Glerup, Mia; Guzman, Jaime; Horneff, Gerd; Kearsley-Fleet, Lianne; Klein, Ariane; Klotsche, Jens; Magnusson, Bo; Minden, Kirsten; Munro, Jane E; Niewerth, Martina; Nordal, Ellen; Ruperto, Nicolino; Santos, Maria Jose; Schanberg, Laura E; Thomson, Wendy; van Suijlekom-Smit, Lisette; Wulffraat, Nico; Hyrich, Kimme

2017-04-19

To characterize the existing national and multi-national registries and cohort studies in juvenile idiopathic arthritis (JIA) and identify differences as well as areas of potential future collaboration. We surveyed investigators from North America, Europe, and Australia about existing JIA cohort studies and registries. We excluded cross-sectional studies. We captured information about study design, duration, location, inclusion criteria, data elements and collection methods. We received survey results from 18 studies, including 11 national and 7 multi-national studies representing 37 countries in total. Study designs included inception cohorts, prevalent disease cohorts, and new treatment cohorts (several of which contribute to pharmacosurveillance activities). Despite numerous differences, the data elements collected across the studies was quite similar, with most studies collecting at least 5 of the 6 American College of Rheumatology core set variables and the data needed to calculate the 3-variable clinical juvenile disease activity score. Most studies were collecting medication initiation and discontinuation dates and were attempting to capture serious adverse events. There is a wide-range of large, ongoing JIA registries and cohort studies around the world. Our survey results indicate significant potential for future collaborative work using data from different studies and both combined and comparative analyses.

A novel accelerometer-based method to describe day-to-day exposure to potentially osteogenic vertical impacts in older adults: findings from a multi-cohort study.

PubMed

Hannam, K; Deere, K C; Hartley, A; Clark, E M; Coulson, J; Ireland, A; Moss, C; Edwards, M H; Dennison, E; Gaysin, T; Cooper, R; Wong, A; McPhee, J S; Cooper, C; Kuh, D; Tobias, J H

2017-03-01

This observational study assessed vertical impacts experienced in older adults as part of their day-to-day physical activity using accelerometry and questionnaire data. Population-based older adults experienced very limited high-impact activity. The accelerometry method utilised appeared to be valid based on comparisons between different cohorts and with self-reported activity. We aimed to validate a novel method for evaluating day-to-day higher impact weight-bearing physical activity (PA) in older adults, thought to be important in protecting against osteoporosis, by comparing results between four cohorts varying in age and activity levels, and with self-reported PA levels. Participants were from three population-based cohorts, MRC National Survey of Health and Development (NSHD), Hertfordshire Cohort Study (HCS) and Cohort for Skeletal Health in Bristol and Avon (COSHIBA), and the Master Athlete Cohort (MAC). Y-axis peaks (reflecting the vertical when an individual is upright) from a triaxial accelerometer (sampling frequency 50 Hz, range 0-16 g) worn at the waist for 7 days were classified as low (0.5-1.0 g), medium (1.0-1.5 g) or higher (≥1.5 g) impacts. There were a median of 90, 41 and 39 higher impacts/week in NSHD (age 69.5), COSHIBA (age 76.8) and HCS (age 78.5) participants, respectively (total n = 1512). In contrast, MAC participants (age 68.5) had a median of 14,322 higher impacts/week. In the three population cohorts combined, based on comparison of beta coefficients, moderate-high-impact activities as assessed by PA questionnaire were suggestive of stronger association with higher impacts from accelerometers (0.25 [0.17, 0.34]), compared with medium (0.18 [0.09, 0.27]) and low impacts (0.13 [0.07,0.19]) (beta coefficient, with 95 % CI). Likewise in MAC, reported moderate-high-impact activities showed a stronger association with higher impacts (0.26 [0.14, 0.37]), compared with medium (0.14 [0.05, 0.22]) and low impacts (0.03 [-0.02, 0.08]). Our new accelerometer method appears to provide valid measures of higher vertical impacts in older adults. Results obtained from the three population-based cohorts indicate that older adults generally experience very limited higher impact weight-bearing PA.

Estimating time-varying exposure-outcome associations using case-control data: logistic and case-cohort analyses.

PubMed

Keogh, Ruth H; Mangtani, Punam; Rodrigues, Laura; Nguipdop Djomo, Patrick

2016-01-05

Traditional analyses of standard case-control studies using logistic regression do not allow estimation of time-varying associations between exposures and the outcome. We present two approaches which allow this. The motivation is a study of vaccine efficacy as a function of time since vaccination. Our first approach is to estimate time-varying exposure-outcome associations by fitting a series of logistic regressions within successive time periods, reusing controls across periods. Our second approach treats the case-control sample as a case-cohort study, with the controls forming the subcohort. In the case-cohort analysis, controls contribute information at all times they are at risk. Extensions allow left truncation, frequency matching and, using the case-cohort analysis, time-varying exposures. Simulations are used to investigate the methods. The simulation results show that both methods give correct estimates of time-varying effects of exposures using standard case-control data. Using the logistic approach there are efficiency gains by reusing controls over time and care should be taken over the definition of controls within time periods. However, using the case-cohort analysis there is no ambiguity over the definition of controls. The performance of the two analyses is very similar when controls are used most efficiently under the logistic approach. Using our methods, case-control studies can be used to estimate time-varying exposure-outcome associations where they may not previously have been considered. The case-cohort analysis has several advantages, including that it allows estimation of time-varying associations as a continuous function of time, while the logistic regression approach is restricted to assuming a step function form for the time-varying association.

Social and Behavioural Outcomes in Children Diagnosed with Autism Spectrum Disorders: A Longitudinal Cohort Study

ERIC Educational Resources Information Center

Russell, Ginny; Golding, Jean; Norwich, Brahm; Emond, Alan; Ford, Tamsin; Steer, Colin

2012-01-01

Objective: To compare social and behavioural outcomes between children formally diagnosed with autism spectrum disorders (ASD) with those of children who displayed autistic traits at preschool age, but remained undiagnosed as teenagers. Method: A secondary analysis of data from a birth cohort study, the Avon Longitudinal Study of Parents and…

Involvement in Bullying and Suicide-Related Behavior at 11 Years: A Prospective Birth Cohort Study

ERIC Educational Resources Information Center

Winsper, Catherine; Lereya, Tanya; Zanarini, Mary; Wolke, Dieter

2012-01-01

Objective: To study the prospective link between involvement in bullying (bully, victim, bully/victim), and subsequent suicide ideation and suicidal/self-injurious behavior, in preadolescent children in the United Kingdom. Method: A total of 6,043 children in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort were assessed to…

Child Maltreatment in the "Children of the Nineties": A Cohort Study of Risk Factors

ERIC Educational Resources Information Center

Sidebotham, Peter; Heron, Jon

2006-01-01

Aim: To analyze the multiple factors affecting the risk of maltreatment in young children within a comprehensive theoretical framework. Methods: The research is based on a large UK cohort study, the Avon Longitudinal Study of Parents and Children. Out of 14,256 children participating in the study, 293 were investigated by social services for…

Disability Rises Gradually for a Cohort of Older Americans

PubMed Central

Brown, Dustin C.; Zajacova, Anna

2017-01-01

Objectives: We study changes in average disability over nearly two decades for a large epidemiological cohort of older Americans. As some people exit by mortality, do average disability levels for the living cohort rise rapidly, rise gradually, stay steady, or decline? Method: Data are from the Study of Asset and Health Dynamics Among the Oldest Old (AHEAD) cohort for 1993–2010. Cohort members are aged 70+ in 1993 (mean = 77.5 years), and the survivors are aged 87+ in 2010 (mean = 90.2 years). Personal care disability (activities of daily living), household management disability (instrumental activities of daily living), and physical limitations are studied. We study average disability for the living cohort over time and the disability histories for decedent and survivor groups. Results: Average disability rises gradually over time for the living cohort. Earlier decedent groups have higher average disability than later ones. Near death, disability rises sharply for all decedent groups. Longer surviving groups have less average disability, and slower disability increases, than shorter surviving groups. All results are repeated for younger cohort members (baseline age = 70–79 years), older ones (baseline age = 80+ years), women, and men. Discussion: As a cohort ages, average disability among living members increases gradually, signaling behavioral, psychological, and biological fitness in very old persons. PMID:26968638

An evaluation of exact matching and propensity score methods as applied in a comparative effectiveness study of inhaled corticosteroids in asthma

PubMed Central

Burden, Anne; Roche, Nicolas; Miglio, Cristiana; Hillyer, Elizabeth V; Postma, Dirkje S; Herings, Ron MC; Overbeek, Jetty A; Khalid, Javaria Mona; van Eickels, Daniela; Price, David B

2017-01-01

Background Cohort matching and regression modeling are used in observational studies to control for confounding factors when estimating treatment effects. Our objective was to evaluate exact matching and propensity score methods by applying them in a 1-year pre–post historical database study to investigate asthma-related outcomes by treatment. Methods We drew on longitudinal medical record data in the PHARMO database for asthma patients prescribed the treatments to be compared (ciclesonide and fine-particle inhaled corticosteroid [ICS]). Propensity score methods that we evaluated were propensity score matching (PSM) using two different algorithms, the inverse probability of treatment weighting (IPTW), covariate adjustment using the propensity score, and propensity score stratification. We defined balance, using standardized differences, as differences of <10% between cohorts. Results Of 4064 eligible patients, 1382 (34%) were prescribed ciclesonide and 2682 (66%) fine-particle ICS. The IPTW and propensity score-based methods retained more patients (96%–100%) than exact matching (90%); exact matching selected less severe patients. Standardized differences were >10% for four variables in the exact-matched dataset and <10% for both PSM algorithms and the weighted pseudo-dataset used in the IPTW method. With all methods, ciclesonide was associated with better 1-year asthma-related outcomes, at one-third the prescribed dose, than fine-particle ICS; results varied slightly by method, but direction and statistical significance remained the same. Conclusion We found that each method has its particular strengths, and we recommend at least two methods be applied for each matched cohort study to evaluate the robustness of the findings. Balance diagnostics should be applied with all methods to check the balance of confounders between treatment cohorts. If exact matching is used, the calculation of a propensity score could be useful to identify variables that require balancing, thereby informing the choice of matching criteria together with clinical considerations. PMID:28356782

[The design of a nationwide cohort study in Germany : the pretest studies of the German National Cohort (GNC)].

PubMed

Ahrens, W; Greiser, H; Linseisen, J; Kluttig, A; Schipf, S; Schmidt, B; Günther, K

2014-11-01

The German National Cohort (GNC) is the largest population-based cohort study in Germany. Beginning in 2014, a total of 200,000 women and men aged 20-69 years will be examined in 18 study centers. The aim of the study is to investigate the etiology of chronic diseases in relation to lifestyle, genetic, socioeconomic, and environmental factors and to develop appropriate methods for early diagnosis and prevention of diseases such as cardiovascular and respiratory diseases, cancer, diabetes, neurodegenerative/psychiatric diseases, as well as musculoskeletal and infectious diseases. Pretest studies (phase 1 and 2) were conducted to select methods, instruments, and procedures for the main study, to develop standard operating procedures, and to design and test the examination program according to acceptance, expected duration, and feasibility. The pretest studies included testing of interviews, questionnaires, anthropometric measurements, several medical examinations, and the collection of biosamples. In addition, the logistic, technical, and personnel infrastructure for the main study could be established including the study centers, the central infrastructure for data management, processes to coordinate the study, and data protection and quality management concepts. The examination program for the main phase of the GNC was designed and optimized based on the results of the pretest studies. The GNC is a population-based, highly standardized and excellently phenotyped cohort that will be the basis for new strategies for risk assessment and identification, early diagnosis, and prevention of multifactorial diseases.

Computerized test versus personal interview as admission methods for graduate nursing studies: A retrospective cohort study.

PubMed

Hazut, Koren; Romem, Pnina; Malkin, Smadar; Livshiz-Riven, Ilana

2016-12-01

The purpose of this study was to compare the predictive validity, economic efficiency, and faculty staff satisfaction of a computerized test versus a personal interview as admission methods for graduate nursing studies. A mixed method study was designed, including cross-sectional and retrospective cohorts, interviews, and cost analysis. One hundred and thirty-four students in the Master of Nursing program participated. The success of students in required core courses was similar in both admission method groups. The personal interview method was found to be a significant predictor of success, with cognitive variables the only significant contributors to the model. Higher satisfaction levels were reported with the computerized test compared with the personal interview method. The cost of the personal interview method, in annual hourly work, was 2.28 times higher than the computerized test. These findings may promote discussion regarding the cost benefit of the personal interview as an admission method for advanced academic studies in healthcare professions. © 2016 John Wiley & Sons Australia, Ltd.

Stuttering, Temperament, and Anxiety: Data from a Community Cohort Ages 2-4 Years

ERIC Educational Resources Information Center

Kefalianos, Elaina; Onslow, Mark; Ukoumunne, Obioha; Block, Susan; Reilly, Sheena

2014-01-01

Purpose: The purpose of this study was to ascertain whether and when temperament differences, including precursors of anxiety, emerge before onset and during stuttering development. Method: The authors prospectively studied temperament characteristics of a community cohort of children who stutter (N = 183) and children in the control group (N =…

Temperament and Early Stuttering Development: Cross-Sectional Findings from a Community Cohort

ERIC Educational Resources Information Center

Kefalianos, Elaina; Onslow, Mark; Ukoumunne, Obioha C.; Block, Susan; Reilly, Sheena

2017-01-01

Purpose: The purpose of this study was to ascertain if there is an association between stuttering severity and behaviors and the expression of temperament characteristics, including precursors of anxiety. Method: We studied temperament characteristics of a prospectively recruited community cohort of children who stutter (N = 173) at ages 3, 4, and…

Overview of the Japan Children’s Study 2004–2009; Cohort Study of Early Childhood Development

PubMed Central

Yamagata, Zentaro; Maeda, Tadahiko; Anme, Tokie; Sadato, Norihiro

2010-01-01

Background There are still a lot of unknown aspects about the childhood development of sociability which are based on neuroscientific basis. Purpose of the Japan Children’s Study (JCS) was to verify the normal process of child development of sociability; the trajectory and factors related development of sociability, and to collect findings and integrate the knowledge to make the plan of long-term and large scale cohort study. Methods A child cohort study underway in Japan since 2005. There are the cohort study including a infant cohort study at age of 4 months to 30 months and a preschool cohort study at age of 5 years old to 8 years old. Questionnaires, direct observation of children and cognitive testing were performed. Results In infant cohort study, 465 infants were recruited at 4 months and 367 children were followed up to 30 months, follow up rate was 78.9% and in the preschool cohort study, total 192 children (112 at 2005 and 80 at 2007) at age of 5 years old and 169 followed up to 6 years (follow up rate was 88.0%), and 79 children were followed up to 8 years old (follow up rate was 70.5%) old. Several new measurements to evaluate child sociability were developed. Some factors related to development of child sociability were found for example the ‘praise’ was related to child sociability in cohort study based on neuroscience findings. Conclusions Though the trajectory of child sociability development were not clarified, some significant factors related to development of sociability, and the basic findings to conduct a long-term and large scale cohort study were provided. PMID:20179361

An evaluation of exact matching and propensity score methods as applied in a comparative effectiveness study of inhaled corticosteroids in asthma.

PubMed

Burden, Anne; Roche, Nicolas; Miglio, Cristiana; Hillyer, Elizabeth V; Postma, Dirkje S; Herings, Ron Mc; Overbeek, Jetty A; Khalid, Javaria Mona; van Eickels, Daniela; Price, David B

2017-01-01

Cohort matching and regression modeling are used in observational studies to control for confounding factors when estimating treatment effects. Our objective was to evaluate exact matching and propensity score methods by applying them in a 1-year pre-post historical database study to investigate asthma-related outcomes by treatment. We drew on longitudinal medical record data in the PHARMO database for asthma patients prescribed the treatments to be compared (ciclesonide and fine-particle inhaled corticosteroid [ICS]). Propensity score methods that we evaluated were propensity score matching (PSM) using two different algorithms, the inverse probability of treatment weighting (IPTW), covariate adjustment using the propensity score, and propensity score stratification. We defined balance, using standardized differences, as differences of <10% between cohorts. Of 4064 eligible patients, 1382 (34%) were prescribed ciclesonide and 2682 (66%) fine-particle ICS. The IPTW and propensity score-based methods retained more patients (96%-100%) than exact matching (90%); exact matching selected less severe patients. Standardized differences were >10% for four variables in the exact-matched dataset and <10% for both PSM algorithms and the weighted pseudo-dataset used in the IPTW method. With all methods, ciclesonide was associated with better 1-year asthma-related outcomes, at one-third the prescribed dose, than fine-particle ICS; results varied slightly by method, but direction and statistical significance remained the same. We found that each method has its particular strengths, and we recommend at least two methods be applied for each matched cohort study to evaluate the robustness of the findings. Balance diagnostics should be applied with all methods to check the balance of confounders between treatment cohorts. If exact matching is used, the calculation of a propensity score could be useful to identify variables that require balancing, thereby informing the choice of matching criteria together with clinical considerations.

Analysis of Clinical Cohort Data Using Nested Case-control and Case-cohort Sampling Designs. A Powerful and Economical Tool.

PubMed

Ohneberg, K; Wolkewitz, M; Beyersmann, J; Palomar-Martinez, M; Olaechea-Astigarraga, P; Alvarez-Lerma, F; Schumacher, M

2015-01-01

Sampling from a large cohort in order to derive a subsample that would be sufficient for statistical analysis is a frequently used method for handling large data sets in epidemiological studies with limited resources for exposure measurement. For clinical studies however, when interest is in the influence of a potential risk factor, cohort studies are often the first choice with all individuals entering the analysis. Our aim is to close the gap between epidemiological and clinical studies with respect to design and power considerations. Schoenfeld's formula for the number of events required for a Cox' proportional hazards model is fundamental. Our objective is to compare the power of analyzing the full cohort and the power of a nested case-control and a case-cohort design. We compare formulas for power for sampling designs and cohort studies. In our data example we simultaneously apply a nested case-control design with a varying number of controls matched to each case, a case cohort design with varying subcohort size, a random subsample and a full cohort analysis. For each design we calculate the standard error for estimated regression coefficients and the mean number of distinct persons, for whom covariate information is required. The formula for the power of a nested case-control design and the power of a case-cohort design is directly connected to the power of a cohort study using the well known Schoenfeld formula. The loss in precision of parameter estimates is relatively small compared to the saving in resources. Nested case-control and case-cohort studies, but not random subsamples yield an attractive alternative for analyzing clinical studies in the situation of a low event rate. Power calculations can be conducted straightforwardly to quantify the loss of power compared to the savings in the num-ber of patients using a sampling design instead of analyzing the full cohort.

Gender Differences of Children's Developmental Trajectory from 6 to 60 Months in the Taiwan Birth Cohort Pilot Study

ERIC Educational Resources Information Center

Lung, For-Wey; Chiang, Tung-Liang; Lin, Shio-Jean; Feng, Jui-Ying; Chen, Po-Fei; Shu, Bih-Ching

2011-01-01

The parental report instrument is the most efficient developmental detection method and has shown high validity with professional assessment instruments. The reliability and validity of the Taiwan Birth Cohort Study (TBCS) 6-, 18- and 36-month scales have already been established. In this study, the reliability and validity of the 60-month scale…

Very Early Predictors of Conduct Problems and Crime: Results from a National Cohort Study

ERIC Educational Resources Information Center

Murray, Joseph; Irving, Barrie; Farrington, David P.; Colman, Ian; Bloxsom, Claire A. J.

2010-01-01

Background: Longitudinal research has produced a wealth of knowledge about individual, family, and social predictors of crime. However, nearly all studies have started after children are age 5, and little is known about earlier risk factors. Methods: The 1970 British Cohort Study is a prospective population survey of more than 16,000 children born…

Proton pump inhibitors and the risk of pneumonia: a comparison of cohort and self-controlled case series designs

PubMed Central

2013-01-01

Background To compare the results of a new-user cohort study design and the self-controlled case series (SCCS) design using the risk of hospitalisation for pneumonia in those dispensed proton pump inhibitors compared to those unexposed as a case study. Methods The Australian Government Department of Veterans’ Affairs administrative claims database was used. Exposure to proton pump inhibitors and hospitalisations for pneumonia were identified over a 4 year study period 01 Jul 2007 -30 Jun 2011. The same inclusion and exclusion criteria were applied to both studies, however, the SCCS study included subjects with a least one hospitalisation for pneumonia. Results There were 105,467 subjects included in the cohort study and 6775 in the SCCS. Both studies showed an increased risk of hospitalisations for pneumonia in the three defined risk periods following initiation of proton pump inhibitors compared to baseline. With the highest risk in the first 1 to 7 days (Cohort RR, 3.24; 95% CI (2.50, 4.19): SCCS: RR, 3.07; 95% CI (2.69, 3.50)). Conclusions This study has shown that the self-controlled case series method produces similar risk estimates to a new-users cohort study design when applied to the association of proton pump inhibitors and pneumonia. Exposure to a proton pump inhibitor increases the likelihood of being admitted to hospital for pneumonia, with the risk highest in the first week of treatment. PMID:23800078

Association between Recruitment Methods and Attrition in Internet-Based Studies

PubMed Central

Bajardi, Paolo; Paolotti, Daniela; Vespignani, Alessandro; Eames, Ken; Funk, Sebastian; Edmunds, W. John; Turbelin, Clement; Debin, Marion; Colizza, Vittoria; Smallenburg, Ronald; Koppeschaar, Carl; Franco, Ana O.; Faustino, Vitor; Carnahan, AnnaSara; Rehn, Moa; Merletti, Franco; Douwes, Jeroen; Firestone, Ridvan; Richiardi, Lorenzo

2014-01-01

Internet-based systems for epidemiological studies have advantages over traditional approaches as they can potentially recruit and monitor a wider range of individuals in a relatively inexpensive fashion. We studied the association between communication strategies used for recruitment (offline, online, face-to-face) and follow-up participation in nine Internet-based cohorts: the Influenzanet network of platforms for influenza surveillance which includes seven cohorts in seven different European countries, the Italian birth cohort Ninfea and the New Zealand birth cohort ELF. Follow-up participation varied from 43% to 89% depending on the cohort. Although there were heterogeneities among studies, participants who became aware of the study through an online communication campaign compared with those through traditional offline media seemed to have a lower follow-up participation in 8 out of 9 cohorts. There were no clear differences in participation between participants enrolled face-to-face and those enrolled through other offline strategies. An Internet-based campaign for Internet-based epidemiological studies seems to be less effective than an offline one in enrolling volunteers who keep participating in follow-up questionnaires. This suggests that even for Internet-based epidemiological studies an offline enrollment campaign would be helpful in order to achieve a higher participation proportion and limit the cohort attrition. PMID:25490045

Impact of teaching and assessment format on electrocardiogram interpretation skills.

PubMed

Raupach, Tobias; Hanneforth, Nathalie; Anders, Sven; Pukrop, Tobias; Th J ten Cate, Olle; Harendza, Sigrid

2010-07-01

Interpretation of the electrocardiogram (ECG) is a core clinical skill that should be developed in undergraduate medical education. This study assessed whether small-group peer teaching is more effective than lectures in enhancing medical students' ECG interpretation skills. In addition, the impact of assessment format on study outcome was analysed. Two consecutive cohorts of Year 4 medical students (n=335) were randomised to receive either traditional ECG lectures or the same amount of small-group, near-peer teaching during a 6-week cardiorespiratory course. Before and after the course, written assessments of ECG interpretation skills were undertaken. Whereas this final assessment yielded a considerable amount of credit points for students in the first cohort, it was merely formative in nature for the second cohort. An unannounced retention test was applied 8 weeks after the end of the cardiovascular course. A significant advantage of near-peer teaching over lectures (effect size 0.33) was noted only in the second cohort, whereas, in the setting of a summative assessment, both teaching formats appeared to be equally effective. A summative instead of a formative assessment doubled the performance increase (Cohen's d 4.9 versus 2.4), mitigating any difference between teaching formats. Within the second cohort, the significant difference between the two teaching formats was maintained in the retention test (p=0.017). However, in both cohorts, a significant decrease in student performance was detected during the 8 weeks following the cardiovascular course. Assessment format appeared to be more powerful than choice of instructional method in enhancing student learning. The effect observed in the second cohort was masked by an overriding incentive generated by the summative assessment in the first cohort. This masking effect should be considered in studies assessing the effectiveness of different teaching methods.

Impact of Perinatal Different Intrauterine Environments on Child Growth and Development in the First Six Months of Life--IVAPSA Birth Cohort: rationale, design, and methods.

PubMed

Bernardi, Juliana Rombaldi; Ferreira, Charles Francisco; Nunes, Marina; da Silva, Clécio Homrich; Bosa, Vera Lúcia; Silveira, Patrícia Pelufo; Goldani, Marcelo Zubaran

2012-04-02

In the last twenty years, retrospective studies have shown that perinatal events may impact the individual health in the medium and long term. However, only a few prospective studies were designed to address this phenomenon. This study aims to describe the design and methods of the Impact of Perinatal Environmental Variations in the First Six Months of Life - the IVAPSA Birth Cohort. This is a clinical study and involves the recruitment of a birth cohort from hospitals in Porto Alegre, Rio Grande do Sul, Brazil. Mothers from different clinical backgrounds (hypertensive, diabetics, smokers, having an intrauterine growth restricted child for idiopathic reasons, and controls) will be invited to join the study twenty-four hours after the birth of their child. Data on economic, social, and maternal health care, feeding practices, anthropometric measures, physical activity, and neuropsychological evaluation will be obtained in interviews at postpartum, 7 and 15 days, 1, 3 and 6 months of life. To our knowledge, this is the first thematic cohort focused on the effects of intrauterine growth restriction to prospectively enroll mothers from different clinical backgrounds. The IVAPSA Birth Cohort is a promising research platform that can contribute to the knowledge on the relationship between perinatal events and their consequences on the children's early life.

Assessing the order of magnitude of outcomes in single-arm cohorts through systematic comparison with corresponding cohorts: An example from the AMOS study

PubMed Central

Hamre, Harald J; Glockmann, Anja; Tröger, Wilfried; Kienle, Gunver S; Kiene, Helmut

2008-01-01

Background When a therapy has been evaluated in the first clinical study, the outcome is often compared descriptively to outcomes in corresponding cohorts receiving other treatments. Such comparisons are often limited to selected studies, and often mix different outcomes and follow-up periods. Here we give an example of a systematic comparison to all cohorts with identical outcomes and follow-up periods. Methods The therapy to be compared (anthroposophic medicine, a complementary therapy system) had been evaluated in one single-arm cohort study: the Anthroposophic Medicine Outcomes Study (AMOS). The five largest AMOS diagnosis groups (A-cohorts: asthma, depression, low back pain, migraine, neck pain) were compared to all retrievable corresponding cohorts (C-cohorts) receiving other therapies with identical outcomes (SF-36 scales or summary measures) and identical follow-up periods (3, 6 or 12 months). Between-group differences (pre-post difference in an A-cohort minus pre-post difference in the respective C-cohort) were divided with the standard deviation (SD) of the baseline score of the A-cohort. Results A-cohorts (5 cohorts with 392 patients) were similar to C-cohorts (84 cohorts with 16,167 patients) regarding age, disease duration, baseline affection and follow-up rates. A-cohorts had ≥ 0.50 SD larger improvements than C-cohorts in 13.5% (70/517) of comparisons; improvements of the same order of magnitude (small or minimal differences: -0.49 to 0.49 SD) were found in 80.1% of comparisons; and C-cohorts had ≥ 0.50 SD larger improvements than A-cohorts in 6.4% of comparisons. Analyses stratified by diagnosis had similar results. Sensitivity analyses, restricting the comparisons to C-cohorts with similar study design (observational studies), setting (primary care) or interventions (drugs, physical therapies, mixed), or restricting comparisons to SF-36 scales with small baseline differences between A- and C-cohorts (-0.49 to 0.49 SD) also had similar results. Conclusion In this descriptive analysis, anthroposophic therapy was associated with SF-36 improvements largely of the same order of magnitude as improvements following other treatments. Although these non-concurrent comparisons cannot assess comparative effectiveness, they suggest that improvements in health status following anthroposophic therapy can be clinically meaningful. The analysis also demonstrates the value of a systematic approach when comparing a therapy cohort to corresponding therapy cohorts. PMID:18366683

Three-Year Study of Students' Attitudes toward Physical Education: Grades 4-8

ERIC Educational Resources Information Center

Mercier, Kevin; Donovan, Corinne; Gibbone, Anne; Rozga, Kimberly

2017-01-01

Purpose: A relationship exists between attitudes toward physical education and future physical activity. The purpose of this study was to examine changes in attitude toward physical education as students progressed from upper elementary school (Grade 4) through middle school (Grade 8). Method: Three cohorts of students (Cohort 1, Grades 4-6,…

A hybrid model for combining case-control and cohort studies in systematic reviews of diagnostic tests

PubMed Central

Chen, Yong; Liu, Yulun; Ning, Jing; Cormier, Janice; Chu, Haitao

2014-01-01

Systematic reviews of diagnostic tests often involve a mixture of case-control and cohort studies. The standard methods for evaluating diagnostic accuracy only focus on sensitivity and specificity and ignore the information on disease prevalence contained in cohort studies. Consequently, such methods cannot provide estimates of measures related to disease prevalence, such as population averaged or overall positive and negative predictive values, which reflect the clinical utility of a diagnostic test. In this paper, we propose a hybrid approach that jointly models the disease prevalence along with the diagnostic test sensitivity and specificity in cohort studies, and the sensitivity and specificity in case-control studies. In order to overcome the potential computational difficulties in the standard full likelihood inference of the proposed hybrid model, we propose an alternative inference procedure based on the composite likelihood. Such composite likelihood based inference does not suffer computational problems and maintains high relative efficiency. In addition, it is more robust to model mis-specifications compared to the standard full likelihood inference. We apply our approach to a review of the performance of contemporary diagnostic imaging modalities for detecting metastases in patients with melanoma. PMID:25897179

Clinical effectiveness of late maxillary protraction in cleft lip and palate: a methods paper

PubMed Central

Lee, MK; Lane, C; Azeredo, F; Landsberger, M; Kapadia, H; Sheller, B; Yen, SL

2017-01-01

Objectives A prospective parallel cohort trial was conducted to compare outcomes of patients treated with maxillary protraction vs. LeFort 1 maxillary advancement surgery. Setting and Sample Population The primary site for the clinical trial is Children’s Hospital Los Angeles; the satellite test site is Seattle Children’s Hospital. All patients have isolated cleft lip and palate and a skeletal Class III malocclusion. Material & Methods A total of 50 patients, ages 11–14 will be recruited for the maxillary protraction cohort. The maxillary surgery cohort consists of 50 patients, ages 16–21, who will undergo LeFort 1 maxillary advancement surgery. Patients with additional medical or cognitive handicaps were excluded from the study. Results Current recruitment of patients is on track to complete the study within the proposed recruitment period. Conclusion This observational trial is collecting information that will examine dental, skeletal, financial, and quality of life issues from both research cohorts. PMID:28643931

Study Protocol, Sample Characteristics, and Loss to Follow-Up: The OPPERA Prospective Cohort Study

PubMed Central

Bair, Eric; Brownstein, Naomi C.; Ohrbach, Richard; Greenspan, Joel D.; Dubner, Ron; Fillingim, Roger B.; Maixner, William; Smith, Shad; Diatchenko, Luda; Gonzalez, Yoly; Gordon, Sharon; Lim, Pei-Feng; Ribeiro-Dasilva, Margarete; Dampier, Dawn; Knott, Charles; Slade, Gary D.

2013-01-01

When studying incidence of pain conditions such as temporomandibular disorders (TMDs), repeated monitoring is needed in prospective cohort studies. However, monitoring methods usually have limitations and, over a period of years, some loss to follow-up is inevitable. The OPPERA prospective cohort study of first-onset TMD screened for symptoms using quarterly questionnaires and examined symptomatic participants to definitively ascertain TMD incidence. During the median 2.8-year observation period, 16% of the 3,263 enrollees completed no follow-up questionnaires, others provided incomplete follow-up, and examinations were not conducted for one third of symptomatic episodes. Although screening methods and examinations were found to have excellent reliability and validity, they were not perfect. Loss to follow-up varied according to some putative TMD risk factors, although multiple imputation to correct the problem suggested that bias was minimal. A second method of multiple imputation that evaluated bias associated with omitted and dubious examinations revealed a slight underestimate of incidence and some small biases in hazard ratios used to quantify effects of risk factors. Although “bottom line” statistical conclusions were not affected, multiply-imputed estimates should be considered when evaluating the large number of risk factors under investigation in the OPPERA study. Perspective These findings support the validity of the OPPERA prospective cohort study for the purpose of investigating the etiology of first-onset TMD, providing the foundation for other papers investigating risk factors hypothesized in the OPPERA project. PMID:24275220

Efficient Bayesian mixed model analysis increases association power in large cohorts

PubMed Central

Loh, Po-Ru; Tucker, George; Bulik-Sullivan, Brendan K; Vilhjálmsson, Bjarni J; Finucane, Hilary K; Salem, Rany M; Chasman, Daniel I; Ridker, Paul M; Neale, Benjamin M; Berger, Bonnie; Patterson, Nick; Price, Alkes L

2014-01-01

Linear mixed models are a powerful statistical tool for identifying genetic associations and avoiding confounding. However, existing methods are computationally intractable in large cohorts, and may not optimize power. All existing methods require time cost O(MN2) (where N = #samples and M = #SNPs) and implicitly assume an infinitesimal genetic architecture in which effect sizes are normally distributed, which can limit power. Here, we present a far more efficient mixed model association method, BOLT-LMM, which requires only a small number of O(MN)-time iterations and increases power by modeling more realistic, non-infinitesimal genetic architectures via a Bayesian mixture prior on marker effect sizes. We applied BOLT-LMM to nine quantitative traits in 23,294 samples from the Women’s Genome Health Study (WGHS) and observed significant increases in power, consistent with simulations. Theory and simulations show that the boost in power increases with cohort size, making BOLT-LMM appealing for GWAS in large cohorts. PMID:25642633

[Assessing incident cardiovascular and metabolic diseases in epidemiological cohort studies in Germany].

PubMed

Herrmann, Wolfram J; Weikert, Cornelia; Bergmann, Manuela; Boeing, Heiner; Katzke, Verena A; Kaaks, Rudolf; Tiller, Daniel; Greiser, Karin Halina; Heier, Margit; Meisinger, Christa; Schmidt, Carsten Oliver; Neuhauser, Hannelore; Heidemann, Christin; Jünger, Claus; Wild, Philipp S; Schramm, Sara Helena; Jöckel, Karl-Heinz; Dörr, Marcus; Pischon, Tobias

2018-04-01

Cardiovascular and metabolic diseases are a major cause of mortality and loss of quality of life in Germany. Research into risk factors of these diseases requires large population-based cohort studies. Complete and accurate assessment of the incidence of cardiovascular and metabolic diseases is a key element for valid interpretation of the results from such studies. Our aim was to identify population-based cohort studies with incidence of cardiovascular and metabolic diseases in Germany and to summarize their methods for assessment and classification of disease endpoints, including myocardial infarction, type 2 diabetes, stroke, heart failure, and arterial hypertension. Within the framework of a workshop, representatives of the ascertained population-based cohort studies in Germany with incidence of cardiovascular or metabolic diseases were invited to present and to systematically provide information on their methods of endpoint identification. We identified eight studies from different regions in Germany with a total of 100,571 participants, aged 18-83 years at baseline. Self-reporting by study participants is the major source for further inquiries to assess disease endpoints in these studies. Most studies use additional data sources to verify the incidence of diseases, such as documents provided by the treating physician or hospital. Our results highlight the central role of self-reporting and the efforts associated with identification and verification of disease endpoints in cohort studies. They also provide a basis for future population-based studies that aim for standardized assessment of the incidence of cardiovascular and metabolic diseases.

A new model of wheezing severity in young children using the validated ISAAC wheezing module: A latent variable approach with validation in independent cohorts.

PubMed

Brunwasser, Steven M; Gebretsadik, Tebeb; Gold, Diane R; Turi, Kedir N; Stone, Cosby A; Datta, Soma; Gern, James E; Hartert, Tina V

2018-01-01

The International Study of Asthma and Allergies in Children (ISAAC) Wheezing Module is commonly used to characterize pediatric asthma in epidemiological studies, including nearly all airway cohorts participating in the Environmental Influences on Child Health Outcomes (ECHO) consortium. However, there is no consensus model for operationalizing wheezing severity with this instrument in explanatory research studies. Severity is typically measured using coarsely-defined categorical variables, reducing power and potentially underestimating etiological associations. More precise measurement approaches could improve testing of etiological theories of wheezing illness. We evaluated a continuous latent variable model of pediatric wheezing severity based on four ISAAC Wheezing Module items. Analyses included subgroups of children from three independent cohorts whose parents reported past wheezing: infants ages 0-2 in the INSPIRE birth cohort study (Cohort 1; n = 657), 6-7-year-old North American children from Phase One of the ISAAC study (Cohort 2; n = 2,765), and 5-6-year-old children in the EHAAS birth cohort study (Cohort 3; n = 102). Models were estimated using structural equation modeling. In all cohorts, covariance patterns implied by the latent variable model were consistent with the observed data, as indicated by non-significant χ2 goodness of fit tests (no evidence of model misspecification). Cohort 1 analyses showed that the latent factor structure was stable across time points and child sexes. In both cohorts 1 and 3, the latent wheezing severity variable was prospectively associated with wheeze-related clinical outcomes, including physician asthma diagnosis, acute corticosteroid use, and wheeze-related outpatient medical visits when adjusting for confounders. We developed an easily applicable continuous latent variable model of pediatric wheezing severity based on items from the well-validated ISAAC Wheezing Module. This model prospectively associates with asthma morbidity, as demonstrated in two ECHO birth cohort studies, and provides a more statistically powerful method of testing etiologic hypotheses of childhood wheezing illness and asthma.

Changes in Waist Circumference among German Adults over Time – Compiling Results of Seven Prospective Cohort Studies

PubMed Central

Haftenberger, Marjolein; Mensink, Gert B.M.; Vogt, Susanne; Thorand, Barbara; Peters, Annette; Herzog, Beatrice; Hartwig, Saskia; Greiser, Karin Halina; Ittermann, Till; Schipf, Sabine; Völzke, Henry; Merz, Benedikt; Nöthlings, Ute; Koch, Manja; Neamat-Allah, Jasmine; Katzke, Verena; Kaaks, Rudolf; Boeing, Heiner; Bachlechner, Ursula; Scheidt-Nave, Christa; Schienkiewitz, Anja

2016-01-01

Aim This study aims to quantify longitudinal changes in waist circumference (WC) among adults aged 45–64 years in Germany. Methods Data of 15,444 men and 17,207 women from one nationwide and six regional prospective German cohort studies were analyzed. The sex-specific mean change in WC per year of follow-up was assessed for each study separately. Findings from the cohort-by-cohort analysis were combined by applying meta-analytic methods. Progression to central obesity (WC ≥ 102 cm in men and ≥ 88 cm in women) within a standardized period of 10 years was described for each study. Results The estimated mean change in WC per year of follow-up for all cohorts combined was 0.53 (95s% confidence interval 0.29–0.76) cm/year for men and 0.63 (0.48–0.77) cm/year for women, but varied between the included studies. Within 10 years, about 20s% of individuals with low WC (<94 cm in men; <80 cm in women) and about 50s% of individuals with intermediate WC (94–102 cm in men; 80–88 cm in women) progressed to central obesity. Conclusion The increase in mean WC with aging along with a profound increase of central adiposity is obviously and may have several adverse health effects. Obesity prevention programs should also focus on abdominal obesity. PMID:27701174

DISTMIX: direct imputation of summary statistics for unmeasured SNPs from mixed ethnicity cohorts.

PubMed

Lee, Donghyung; Bigdeli, T Bernard; Williamson, Vernell S; Vladimirov, Vladimir I; Riley, Brien P; Fanous, Ayman H; Bacanu, Silviu-Alin

2015-10-01

To increase the signal resolution for large-scale meta-analyses of genome-wide association studies, genotypes at unmeasured single nucleotide polymorphisms (SNPs) are commonly imputed using large multi-ethnic reference panels. However, the ever increasing size and ethnic diversity of both reference panels and cohorts makes genotype imputation computationally challenging for moderately sized computer clusters. Moreover, genotype imputation requires subject-level genetic data, which unlike summary statistics provided by virtually all studies, is not publicly available. While there are much less demanding methods which avoid the genotype imputation step by directly imputing SNP statistics, e.g. Directly Imputing summary STatistics (DIST) proposed by our group, their implicit assumptions make them applicable only to ethnically homogeneous cohorts. To decrease computational and access requirements for the analysis of cosmopolitan cohorts, we propose DISTMIX, which extends DIST capabilities to the analysis of mixed ethnicity cohorts. The method uses a relevant reference panel to directly impute unmeasured SNP statistics based only on statistics at measured SNPs and estimated/user-specified ethnic proportions. Simulations show that the proposed method adequately controls the Type I error rates. The 1000 Genomes panel imputation of summary statistics from the ethnically diverse Psychiatric Genetic Consortium Schizophrenia Phase 2 suggests that, when compared to genotype imputation methods, DISTMIX offers comparable imputation accuracy for only a fraction of computational resources. DISTMIX software, its reference population data, and usage examples are publicly available at http://code.google.com/p/distmix. dlee4@vcu.edu Supplementary Data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press.

Weight and Veterans' Environments Study (WAVES) I and II: Rationale, Methods, and Cohort Characteristics.

PubMed

Zenk, Shannon N; Tarlov, Elizabeth; Powell, Lisa M; Wing, Coady; Matthews, Stephen A; Slater, Sandy; Gordon, Howard S; Berbaum, Michael; Fitzgibbon, Marian L

2018-03-01

To present the rationale, methods, and cohort characteristics for 2 complementary "big data" studies of residential environment contributions to body weight, metabolic risk, and weight management program participation and effectiveness. Retrospective cohort. Continental United States. A total of 3 261 115 veterans who received Department of Veterans Affairs (VA) health care in 2009 to 2014, including 169 910 weight management program participants and a propensity score-derived comparison group. The VA MOVE! weight management program, an evidence-based lifestyle intervention. Body mass index, metabolic risk measures, and MOVE! participation; residential environmental attributes (eg, food outlet availability and walkability); and MOVE! program characteristics. Descriptive statistics presented on cohort characteristics and environments where they live. Forty-four percent of men and 42.8% of women were obese, whereas 4.9% of men and 9.9% of women engaged in MOVE!. About half of the cohort had at least 1 supermarket within 1 mile of their home, whereas they averaged close to 4 convenience stores (3.6 for men, 3.9 for women) and 8 fast-food restaurants (7.9 for men, 8.2 for women). Forty-one percent of men and 38.6% of women did not have a park, and 35.5% of men and 31.3% of women did not have a commercial fitness facility within 1 mile. Drawing on a large nationwide cohort residing in diverse environments, these studies are poised to significantly inform policy and weight management program design.

Accuracy and generalizability of using automated methods for identifying adverse events from electronic health record data: a validation study protocol.

PubMed

Rochefort, Christian M; Buckeridge, David L; Tanguay, Andréanne; Biron, Alain; D'Aragon, Frédérick; Wang, Shengrui; Gallix, Benoit; Valiquette, Louis; Audet, Li-Anne; Lee, Todd C; Jayaraman, Dev; Petrucci, Bruno; Lefebvre, Patricia

2017-02-16

Adverse events (AEs) in acute care hospitals are frequent and associated with significant morbidity, mortality, and costs. Measuring AEs is necessary for quality improvement and benchmarking purposes, but current detection methods lack in accuracy, efficiency, and generalizability. The growing availability of electronic health records (EHR) and the development of natural language processing techniques for encoding narrative data offer an opportunity to develop potentially better methods. The purpose of this study is to determine the accuracy and generalizability of using automated methods for detecting three high-incidence and high-impact AEs from EHR data: a) hospital-acquired pneumonia, b) ventilator-associated event and, c) central line-associated bloodstream infection. This validation study will be conducted among medical, surgical and ICU patients admitted between 2013 and 2016 to the Centre hospitalier universitaire de Sherbrooke (CHUS) and the McGill University Health Centre (MUHC), which has both French and English sites. A random 60% sample of CHUS patients will be used for model development purposes (cohort 1, development set). Using a random sample of these patients, a reference standard assessment of their medical chart will be performed. Multivariate logistic regression and the area under the curve (AUC) will be employed to iteratively develop and optimize three automated AE detection models (i.e., one per AE of interest) using EHR data from the CHUS. These models will then be validated on a random sample of the remaining 40% of CHUS patients (cohort 1, internal validation set) using chart review to assess accuracy. The most accurate models developed and validated at the CHUS will then be applied to EHR data from a random sample of patients admitted to the MUHC French site (cohort 2) and English site (cohort 3)-a critical requirement given the use of narrative data -, and accuracy will be assessed using chart review. Generalizability will be determined by comparing AUCs from cohorts 2 and 3 to those from cohort 1. This study will likely produce more accurate and efficient measures of AEs. These measures could be used to assess the incidence rates of AEs, evaluate the success of preventive interventions, or benchmark performance across hospitals.

Genetic and Environmental Influences on Developmental Milestones and Movement: Results from the Gemini Cohort Study

ERIC Educational Resources Information Center

Smith, Lee; van Jaarsveld, Cornelia H. M.; Llewellyn, Clare H.; Fildes, Alison; López Sánchez, Guillermo Felipe; Wardle, Jane; Fisher, Abigail

2017-01-01

Purpose: Variability in the timing of infant developmental milestones is poorly understood. We used a twin analysis to estimate genetic and environmental influences on motor development and activity levels in infancy. Method: Data were from the Gemini Study, a twin birth cohort of 2,402 families with twins born in the United Kingdom in 2007.…

Virtual Mentoring of Preservice Teachers

ERIC Educational Resources Information Center

Reese, Jill

2016-01-01

The purpose of the study was to describe music teachers' perceptions of the benefits and challenges they experienced as virtual mentors of preservice music teachers. Each mentor was assigned a cohort of preservice teachers who were enrolled in an elementary general music methods course. Cohorts observed their mentor's teaching via Skype. Mentors…

Area and Family Effects on the Psychopathology of the Millennium Cohort Study Children and Their Older Siblings

ERIC Educational Resources Information Center

Flouri, Eirini; Tzavidis, Nikos; Kallis, Constantinos

2010-01-01

Background: To model and compare contextual (area and family) effects on the psychopathology of children nested in families nested in areas. Method: Data from the first two sweeps of the UK's Millennium Cohort Study were used. The final study sample was 9,630 children clustered in 6,052 families clustered in 1,681 Lower-layer Super Output Areas.…

Chronic Radiation Sickness Among Techa Riverside Residents

DTIC Science & Technology

1998-02-01

people with CRS. Consequently, data listed below are considered tentative; they can- 19 1 0.3 not be used to calculate death rates nor to analyze 20...age cohort 0-14 years Death rates for patients with diagnosed CRS were from the control group; the same age cohort is ab- studied by the cohort method...mortality contains age-specific archives of the civil registrars confirmed the deaths. death rates . Copies were made of the death certificates for de- ceased

Design and Conduct of an Internet-Based Preconception Cohort Study in North America: Pregnancy Study Online.

PubMed

Wise, Lauren A; Rothman, Kenneth J; Mikkelsen, Ellen M; Stanford, Joseph B; Wesselink, Amelia K; McKinnon, Craig; Gruschow, Siobhan M; Horgan, Casie E; Wiley, Aleta S; Hahn, Kristen A; Sørensen, Henrik Toft; Hatch, Elizabeth E

2015-07-01

We launched the Boston University Pregnancy Study Online (PRESTO) to assess the feasibility of carrying out an Internet-based preconception cohort study in the US and Canada. We recruited female participants age 21-45 and their male partners through Internet advertisements, word of mouth, and flyers. Female participants were randomised with 50% probability to receive a subscription to FertilityFriend.com (FF), a web-based programme that collects real-time data on menstrual characteristics. We compared recruitment methods within PRESTO, assessed the cost-efficiency of PRESTO relative to its Danish counterpart (Snart-Gravid), and validated retrospectively reported date of last menstrual period (LMP) against the FF data. After 99 weeks of recruitment (2013-15), 2421 women enrolled; 1384 (57%) invited their male partners to participate, of whom 693 (50%) enrolled. Baseline characteristics were balanced across randomisation groups. Cohort retention was similar among those randomised vs. not randomised to FF (84% vs. 81%). At study enrollment, 56%, 22%, and 22% couples had been trying to conceive for < 3, 3-5, and ≥ 6 months, respectively. The cost per subject enrolled was $146 (2013 US$), which was similar to our companion Danish study and half that of a traditional cohort study. Among FF users who conceived, > 97% reported their LMP on the PRESTO questionnaire within 1 day of the LMP recorded via FF. Use of the Internet as a method of recruitment and follow-up in a North American preconception cohort study was feasible and cost-effective. © 2015 John Wiley & Sons Ltd.

Quantitative food intake in the EPIC-Germany cohorts. European Investigation into Cancer and Nutrition.

PubMed

Schulze, M B; Brandstetter, B R; Kroke, A; Wahrendorf, J; Boeing, H

1999-01-01

The EPIC-Heidelberg and the EPIC-Potsdam studies with about 53,000 study participants represent the German contribution to the EPIC (European Investigation into Cancer and Nutrition) cohort study. Within the EPIC study, standardized 24-hour dietary recalls were applied as a quantitative calibration method in order to estimate the amount of scaling bias introduced by the varying center-specific dietary assessment methods. This article presents intake of food items and food groups in the two German cohorts estimated by 24-hour quantitative dietary recalls. Recalls from 1,013 men and 1,078 women in Heidelberg and 1,032 men and 898 women in Potsdam were included in the analysis. The intake of recorded food items or recipe ingredients as well as fat used for cooking was summarized into 16 main food groups and a variety of different subgroups stratified by sex and weighted for the day of the week and age. In more than 90% of the recalls, consumption of dairy products, cereals and cereal products, bread, fat, and non-alcoholic beverages, particularly coffee/tea, was reported. Inter-cohort evaluations revealed that bread, potatoes, fruit and fat were consumed in higher amounts in the Potsdam cohort while the opposite was found for pasta/rice, non-alcoholic, and alcoholic beverages. It was concluded that the exposure variation was increased by having two instead of one EPIC study centers in Germany. Copyright 1999 S. Karger AG, Basel

Segmentation of the hippocampus by transferring algorithmic knowledge for large cohort processing.

PubMed

Thyreau, Benjamin; Sato, Kazunori; Fukuda, Hiroshi; Taki, Yasuyuki

2018-01-01

The hippocampus is a particularly interesting target for neuroscience research studies due to its essential role within the human brain. In large human cohort studies, bilateral hippocampal structures are frequently identified and measured to gain insight into human behaviour or genomic variability in neuropsychiatric disorders of interest. Automatic segmentation is performed using various algorithms, with FreeSurfer being a popular option. In this manuscript, we present a method to segment the bilateral hippocampus using a deep-learned appearance model. Deep convolutional neural networks (ConvNets) have shown great success in recent years, due to their ability to learn meaningful features from a mass of training data. Our method relies on the following key novelties: (i) we use a wide and variable training set coming from multiple cohorts (ii) our training labels come in part from the output of the FreeSurfer algorithm, and (iii) we include synthetic data and use a powerful data augmentation scheme. Our method proves to be robust, and it has fast inference (<30s total per subject), with trained model available online (https://github.com/bthyreau/hippodeep). We depict illustrative results and show extensive qualitative and quantitative cohort-wide comparisons with FreeSurfer. Our work demonstrates that deep neural-network methods can easily encode, and even improve, existing anatomical knowledge, even when this knowledge exists in algorithmic form. Copyright © 2017 Elsevier B.V. All rights reserved.

A Retrospective Administrative Database Analysis of Suicide Attempts and Completed Suicide in Patients With Chronic Pancreatitis.

PubMed

Chen, Chien-Hua; Lin, Cheng-Li; Hsu, Chung-Y; Kao, Chia-Hung

2018-01-01

Background: The actual incidence rate of suicide attempt and the suicide-related fatality rate (completed suicide) in patients with chronic pancreatitis (CP) have not been mentioned in the literature. Methods: We conducted a nationwide population-based cohort study by analyzing data from Taiwan's National Health Insurance Research Database (NHIRD) to compare the rate of suicide attempt between a CP cohort and a non-CP cohort. For the study cohort, we identified 17,733 patients (age ≥ 20 years) diagnosed as having CP between 2000 and 2010 from the NHIRD in Taiwan. Beneficiaries with no history of CP were matched with the study cohort at a 2:1 ratio according to age, sex, and index date. To determine the incidence of suicide, all patients were followed until the end of 2011 or until their withdrawal from the Taiwan National Health Insurance program. Results: Patients with CP had an increased risk of suicide attempt, compared with those without CP (adjusted hazard ratio [aHR] = 2.72, 95% confidence interval [CI] = 1.69-4.37). The suicide-related fatality in the CP cohort was higher than that in the non-CP cohort, but the difference was not statistically significant (aHR = 1.21, 95% CI = 0.39-3.78). Conclusion: Our population-based cohort study reveals a close association between CP and subsequent suicide attempt. Compared with the non-CP cohort, the suicide-related fatality was higher in the CP cohort, although the result was not statistically significant. These findings necessitate surveying patients with CP and providing psychological support to prevent suicide.

A Retrospective Administrative Database Analysis of Suicide Attempts and Completed Suicide in Patients With Chronic Pancreatitis

PubMed Central

Chen, Chien-Hua; Lin, Cheng-Li; Hsu, Chung-Y.; Kao, Chia-Hung

2018-01-01

Background: The actual incidence rate of suicide attempt and the suicide-related fatality rate (completed suicide) in patients with chronic pancreatitis (CP) have not been mentioned in the literature. Methods: We conducted a nationwide population-based cohort study by analyzing data from Taiwan's National Health Insurance Research Database (NHIRD) to compare the rate of suicide attempt between a CP cohort and a non-CP cohort. For the study cohort, we identified 17,733 patients (age ≥ 20 years) diagnosed as having CP between 2000 and 2010 from the NHIRD in Taiwan. Beneficiaries with no history of CP were matched with the study cohort at a 2:1 ratio according to age, sex, and index date. To determine the incidence of suicide, all patients were followed until the end of 2011 or until their withdrawal from the Taiwan National Health Insurance program. Results: Patients with CP had an increased risk of suicide attempt, compared with those without CP (adjusted hazard ratio [aHR] = 2.72, 95% confidence interval [CI] = 1.69–4.37). The suicide-related fatality in the CP cohort was higher than that in the non-CP cohort, but the difference was not statistically significant (aHR = 1.21, 95% CI = 0.39–3.78). Conclusion: Our population-based cohort study reveals a close association between CP and subsequent suicide attempt. Compared with the non-CP cohort, the suicide-related fatality was higher in the CP cohort, although the result was not statistically significant. These findings necessitate surveying patients with CP and providing psychological support to prevent suicide. PMID:29720951

Sardasht-Iran cohort study of chemical warfare victims: design and methods.

PubMed

Ghazanfari, Tooba; Faghihzadeh, Soghrat; Aragizadeh, Hassan; Soroush, Mohammad-Reza; Yaraee, Roya; Mohammad Hassan, Zuhair; Foroutan, Abbas; Vaez-Mahdavi, Mohammad-Reza; Javadi, Mohammad-Ali; Moaiedmohseni, Sakine; Azizi, Fereidoun; Panahi, Yunes; Mostafaie, Ali; Ghasemi, Hassan; Shams, Jalaleddin; Pourfarzam, Shahryar; Jalali-Nadoushan, Mohammad-Reza; Fallahi, Faramarz; Ebtekar, Massoumeh; Davoudi, Seyyed-Masoud; Ghazanfari, Zeinab; Ardestani, Sussan K; Shariat-Panahi, Shamsa; Moin, Athar; Rezaei, Abbas; Kariminia, Amina; Ajdary, Soheila; Mahmoudi, Mahmoud; Roshan, Rasoul; Ghaderi, Sulayman; Babai, Mahmoud; Naghizadeh, Mohammad-Mehdi; Ghanei, Mohammad-Mostafa

2009-01-01

Insights into long-term clinical consequences of sulfur mustard have emerged from some investigations but less is known about the basic and molecular mechanisms of these complications. Sardasht-Iran Cohort Study is a comprehensive historical cohort study on Sardasht chemical victims' population which was designed to find out the long-term complications of sulfur mustard exposure and the basic mechanisms underlying clinical manifestations. This paper describes the design and methodology of Sardasht-Iran Cohort Study. In Sardasht-Iran Cohort Study, 500 individuals including 372 subjects from Sardasht, as the exposed group, and 128 subjects from Rabat, as the unexposed age-matched control group were evaluated. The exposed group was divided into two groups based on the severity of clinical complications at the time of exposure. Different samples including blood, sputum, saliva, tear, urine, and semen were collected for immunologic, hematologic, biochemical, and other laboratory analysis. Data were gathered from medical records, clinical examinations, laboratory tests, and questionnaires for psychological and lifestyle situations. The important distinctions setting this study apart from the previous ones are discussed. The Sardasht-Iran Cohort Study provides important information on various aspects of long-term consequences of sulfur mustard exposure. This database will provide a better position to suggest guidelines for the diagnosis, treatment, and prevention of delayed complications in the patients exposed to sulfur mustard.

A Validation Method to Determine Missing Years of Birth in a Cohort Study of Shipyard Workers Using Social Security Number.

PubMed

Cabasag, Citadel J; Ziogas, Argyrios; Shehata, Merna; Anton-Culver, Hoda

2016-06-01

The objective of the study is to evaluate the generalizability and feasibility of a prediction method developed by Block et al (1983) to estimate missing age of workers by using their Social Security Numbers (SSNs). Our study used a retrospective occupational cohort of about 15,000 workers from the Long Beach Naval Shipyard (1978 to 1985). Our results showed an 89.2% agreement (P < 0.0001) between the predicted and observed years of birth using Block's method. The correlation increased to 93.1% (P < 0.0001) after our modifications by removing workers with SSNs issued in U.S. territories. The method performed better in shipyard workers who obtained their SSNs after 1950. Although the method is useful in imputing missing age, the accuracy is dependent on the year, age, and location of SSN issuance.

Implementing a flipped classroom approach in a university numerical methods mathematics course

NASA Astrophysics Data System (ADS)

Johnston, Barbara M.

2017-05-01

This paper describes and analyses the implementation of a 'flipped classroom' approach, in an undergraduate mathematics course on numerical methods. The approach replaced all the lecture contents by instructor-made videos and was implemented in the consecutive years 2014 and 2015. The sequential case study presented here begins with an examination of the attitudes of the 2014 cohort to the approach in general as well as analysing their use of the videos. Based on these responses, the instructor makes a number of changes (for example, the use of 'cloze' summary notes and the introduction of an extra, optional tutorial class) before repeating the 'flipped classroom' approach the following year. The attitudes to the approach and the video usage of the 2015 cohort are then compared with the 2014 cohort and further changes that could be implemented for the next cohort are suggested.

Concordance with World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) guidelines for cancer prevention and obesity-related cancer risk in the Framingham Offspring cohort (1991-2008)

USDA-ARS?s Scientific Manuscript database

Purpose: This prospective cohort study evaluates associations between healthful behaviors consistent with WCRF/AICR cancer prevention guidelines and obesity-related cancer risk, as a third of cancers are estimated to be preventable. Methods: The study sample consisted of adults from the Framingham O...

Literacy Outcomes for Primary School Children Who Are Deaf and Hard of Hearing: A Cohort Comparison Study

ERIC Educational Resources Information Center

Harris, Margaret; Terlektsi, Emmanouela; Kyle, Fiona E.

2017-01-01

Purpose: In this study, we compared the language and literacy of two cohorts of children with severe-profound hearing loss, recruited 10 years apart, to determine if outcomes had improved in line with the introduction of newborn hearing screening and access to improved hearing aid technology. Method: Forty-two children with deafness, aged 5-7…

The History of Stuttering by 7 Years of Age: Follow-Up of a Prospective Community Cohort

ERIC Educational Resources Information Center

Kefalianos, Elaina; Onslow, Mark; Packman, Ann; Vogel, Adam; Pezic, Angela; Mensah, Fiona; Conway, Laura; Bavin, Edith; Block, Susan; Reilly, Sheena

2017-01-01

Purpose: For a community cohort of children confirmed to have stuttered by the age of 4 years, we report (a) the recovery rate from stuttering, (b) predictors of recovery, and (c) comorbidities at the age of 7 years. Method: This study was nested in the Early Language in Victoria Study. Predictors of stuttering recovery included child, family, and…

Marginal Structural Models for Case-Cohort Study Designs to Estimate the Association of Antiretroviral Therapy Initiation With Incident AIDS or Death

PubMed Central

Cole, Stephen R.; Hudgens, Michael G.; Tien, Phyllis C.; Anastos, Kathryn; Kingsley, Lawrence; Chmiel, Joan S.; Jacobson, Lisa P.

2012-01-01

To estimate the association of antiretroviral therapy initiation with incident acquired immunodeficiency syndrome (AIDS) or death while accounting for time-varying confounding in a cost-efficient manner, the authors combined a case-cohort study design with inverse probability-weighted estimation of a marginal structural Cox proportional hazards model. A total of 950 adults who were positive for human immunodeficiency virus type 1 were followed in 2 US cohort studies between 1995 and 2007. In the full cohort, 211 AIDS cases or deaths occurred during 4,456 person-years. In an illustrative 20% random subcohort of 190 participants, 41 AIDS cases or deaths occurred during 861 person-years. Accounting for measured confounders and determinants of dropout by inverse probability weighting, the full cohort hazard ratio was 0.41 (95% confidence interval: 0.26, 0.65) and the case-cohort hazard ratio was 0.47 (95% confidence interval: 0.26, 0.83). Standard multivariable-adjusted hazard ratios were closer to the null, regardless of study design. The precision lost with the case-cohort design was modest given the cost savings. Results from Monte Carlo simulations demonstrated that the proposed approach yields approximately unbiased estimates of the hazard ratio with appropriate confidence interval coverage. Marginal structural model analysis of case-cohort study designs provides a cost-efficient design coupled with an accurate analytic method for research settings in which there is time-varying confounding. PMID:22302074

Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields

PubMed Central

2009-01-01

Background The aim of this study was to examine the feasibility of performing a cohort study on health risks from occupational exposure to radiofrequency electromagnetic fields (RF-EMF) in Germany. Methods A set of criteria was developed to evaluate the feasibility of such a cohort study. The criteria aimed at conditions of exposure and exposure assessment (level, duration, preferably on an individual basis), the possibility to assemble a cohort and the feasibility of ascertaining various disease endpoints. Results Twenty occupational settings with workers potentially exposed to RF-EMF and, in addition, a cohort of amateur radio operators were considered. Based on expert ratings, literature reviews and our set of predefined criteria, three of the cohorts were identified as promising for further evaluation: the personnel (technicians) of medium/short wave broadcasting stations, amateur radio operators, and workers on dielectric heat sealers. After further analyses, the cohort of workers on dielectric heat sealers seems not to be feasible due to the small number of exposed workers available and to the difficulty of assessing exposure (exposure depends heavily on the respective working process and mixture of exposures, e.g. plastic vapours), although exposure was highest in this occupational setting. The advantage of the cohort of amateur radio operators was the large number of persons it includes, while the advantage of the cohort of personnel working at broadcasting stations was the quality of retrospective exposure assessment. However, in the cohort of amateur radio operators the exposure assessment was limited, and the cohort of technicians was hampered by the small number of persons working in this profession. Conclusion The majority of occupational groups exposed to RF-EMF are not practicable for setting up an occupational cohort study due to the small numbers of exposed subjects or due to exposure levels being only marginally higher than those of the general public. PMID:19480652

The association between vitamin B12, albuminuria and reduced kidney function: an observational cohort study

USDA-ARS?s Scientific Manuscript database

Background: Variants in CUBN, the gene encoding cubilin, a proximal tubular transport protein, have been associated with albuminuria and vitamin B12 (B12) deficiency. We hypothesized that low levels of B12 would be associated with albuminuria in a population-based cohort. Methods: We analyzed parti...

Socioeconomic Status and Injury in a Cohort of Saskatchewan Farmers

ERIC Educational Resources Information Center

Pickett, William; Day, Andrew G.; Hagel, Louise; Sun, Xiaoqun; Day, Lesley; Marlenga, Barbara; Brison, Robert J.; Pahwa, Punam; Crowe, Trever; Voaklander, Donald C.; Dosman, James

2011-01-01

Purpose: To estimate the strength of relationships between socioeconomic status and injury in a large Canadian farm population. Methods: We conducted a prospective cohort study of 4,769 people from 2,043 farms in Saskatchewan, Canada. Participants reported socioeconomic exposures in 2007 and were followed for the occurrence of injury through 2009…

The Incidence of Infant Physical Abuse in Alaska

ERIC Educational Resources Information Center

Gessner, Bradford D.; Moore, Martha; Hamilton, Bernita; Muth, Pam T.

2004-01-01

Objectives: To determine the incidence of and risk factors associated with infant (less than 1 year of age) physical abuse in Alaska. Methods: A population-based retrospective cohort study for the 1994-2000 resident birth cohort was conducted by linking data from birth certificates, Child Protective Services, a statewide hospital-based trauma…

A Comparative Analysis of Learning Tactics Employed in the Workplace by Leaders from Emerging Generational Cohorts

ERIC Educational Resources Information Center

DePinto, Ross M.

2013-01-01

Much of the relevant literature in the domains of leadership development, succession planning, and cross-generational issues that discusses learning paradigms associated with emerging generational cohorts has been based on qualitative research and anecdotal evidence. In contrast, this study employed quantitative research methods using a validated…

Child Maltreatment and Adolescent Mental Health Problems in a Large Birth Cohort

ERIC Educational Resources Information Center

Mills, Ryan; Scott, James; Alati, Rosa; O'Callaghan, Michael; Najman, Jake M.; Strathearn, Lane

2013-01-01

Objective: To examine whether notified child maltreatment is associated with adverse psychological outcomes in adolescence, and whether differing patterns of psychological outcome are seen depending on the type of maltreatment. Methods: The participants were 7,223 mother and child pairs enrolled in a population-based birth cohort study in…

Closing the Gap Between Attitudes and Perceptions About ICT-Enhanced Learning Among Pre-service STEM Teachers

NASA Astrophysics Data System (ADS)

Barak, Miri

2014-02-01

The goal of this study was to examine pre-service STEM teachers' attitudes and perceptions about the effectiveness of various learning methods and, in specific, the use of information and communication technologies (ICTs) as means for enhancing progressive education. The study was conducted among two cohorts of pre-service STEM teachers (N = 103) in the years 2006 and 2012. The mixed method approach was used to compile data from two research tools: an attitudes questionnaire and reflective drawings. The findings of the first cohort indicated a conflict between the participants' declared attitudes and their perceptions, suggesting a gap between their inclination to coincide with educational trends, and their actual views about the use of ICTs in the classrooms. The first cohort's drawings illustrated ICTs as distractive technologies, ineffective tools for teaching and learning, impairing teachers' authority, and distancing teachers and students from each other. Findings of the second cohort indicated that the gap between attitudes and perceptions was narrowed in such a way that preservice STEM teachers did not see ICTs as threatening, but they perceived them as instrumental for leveraging progressive education.

Adolescent cohorts assessing growth, cardiovascular and cognitive outcomes in low and middle-income countries

PubMed Central

Harrison, Katherine; Viner, Russell M.; Costello, Anthony; Heys, Michelle

2018-01-01

Introduction Life-course studies are needed to explore how exposures during adolescence, particularly puberty, contribute to later cardiovascular risk and cognitive health in low and middle-income countries (LMIC), where 90% of the world’s young people live. The extent of any existing cohorts investigating these outcomes in LMIC has not previously been described. Methods We performed a systematic literature review to identify population cohort studies of adolescents in LMIC that assessed anthropometry and any of cardiovascular risk (blood pressure, physical activity, plasma glucose/lipid profile and substance misuse), puberty (age at menarche, Tanner staging, or other form of pubertal staging) or cognitive outcomes. Studies that recruited participants on the basis of a pre-existing condition or involved less than 500 young people were excluded. Findings 1829 studies were identified, and 24 cohorts fulfilled inclusion criteria based in Asia (10), Africa (6) and South / Central America (8). 14 (58%) of cohorts identified were based in one of four countries; India, Brazil, Vietnam or Ethiopia. Only 2 cohorts included a comprehensive cardiovascular assessment, tanner pubertal staging, and cognitive outcomes. Conclusion Improved utilisation of existing datasets and additional cohort studies of adolescents in LMIC that collect contemporaneous measures of growth, cognition, cardiovascular risk and pubertal development are needed to better understand how this period of the life course influences future non-communicable disease morbidity and cognitive outcomes. PMID:29338025

Study protocol title: a prospective cohort study of low back pain

PubMed Central

2013-01-01

Background Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors. Methods/design A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs. Due to the subjectivity of LBP, six measures of LBP are captured: 1) any LBP, 2) LBP ≥ 5/10 pain rating, 3) LBP with medication use, 4) LBP with healthcare provider visits, 5) LBP necessitating modified work duties and 6) LBP with lost work time. Workers have thus far been enrolled from 30 different employment settings in 4 diverse US states and performed widely varying work. At baseline, workers undergo laptop-administered questionnaires, structured interviews, and two standardized physical examinations to ascertain demographics, medical history, psychosocial factors, hobbies and physical activities, and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of low back pain. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. The lifetime cumulative incidence of low back pain will also include those with a past history of low back pain. Incident cases will exclude prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression. Discussion Data analysis of a prospective cohort study of low back pain is underway and has successfully enrolled over 800 workers to date. PMID:23497211

Multilevel Provider-Based Sampling for Recruitment of Pregnant Women and Mother-Newborn Dyads.

PubMed

McLaughlin, Thomas J; Aupont, Onesky; Kozinetz, Claudia A; Hubble, David; Moore-Simas, Tiffany A; Davis, Deborah; Park, Christina; Brenner, Ruth; Sepavich, Deidre; Felice, Marianne; Caviness, Chantal; Downs, Tim; Selwyn, Beatrice J; Forman, Michele R

2016-06-01

In 2010, the National Children's Study launched 3 alternative recruitment methods to test possible improvements in efficiency compared with traditional household-based recruitment and participant enrollment. In 2012, a fourth method, provider-based sampling (PBS), tested a probability-based sampling of prenatal provider locations supplemented by a second cohort of neonates born at a convenience sample of maternity hospitals. From a sampling frame of 472 prenatal care provider locations and 59 maternity hospitals, 49 provider and 7 hospital locations within or just outside 3 counties participated in study recruitment. During first prenatal care visits or immediately postdelivery at these locations, face-to-face contact was used to screen and recruit eligible women. Of 1450 screened women, 1270 were eligible. Consent rates at prenatal provider locations (62%-74% by county) were similar to those at birth locations (64%-77% by county). During 6 field months, 3 study centers enrolled a total prenatal cohort of 530 women (the majority in the first trimester) and during 2 months enrolled a birth cohort of an additional 320 mother-newborn dyads. As personnel became experienced in the field, the time required to enroll a woman in the prenatal cohort declined from up to 200 hours to 50 to 100 hours per woman recruited. We demonstrated that PBS was feasible and operationally efficient in recruiting a representative cohort of newborns from 3 diverse US counties. Our findings suggest that PBS is a practical approach to recruit large pregnancy and birth cohorts across the United States. Copyright © 2016 by the American Academy of Pediatrics.

Validity of the estimates of oral cholera vaccine effectiveness derived from the test-negative design.

PubMed

Ali, Mohammad; You, Young Ae; Sur, Dipika; Kanungo, Suman; Kim, Deok Ryun; Deen, Jacqueline; Lopez, Anna Lena; Wierzba, Thomas F; Bhattacharya, Sujit K; Clemens, John D

2016-01-20

The test-negative design (TND) has emerged as a simple method for evaluating vaccine effectiveness (VE). Its utility for evaluating oral cholera vaccine (OCV) effectiveness is unknown. We examined this method's validity in assessing OCV effectiveness by comparing the results of TND analyses with those of conventional cohort analyses. Randomized controlled trials of OCV were conducted in Matlab (Bangladesh) and Kolkata (India), and an observational cohort design was used in Zanzibar (Tanzania). For all three studies, VE using the TND was estimated from the odds ratio (OR) relating vaccination status to fecal test status (Vibrio cholerae O1 positive or negative) among diarrheal patients enrolled during surveillance (VE= (1-OR)×100%). In cohort analyses of these studies, we employed the Cox proportional hazard model for estimating VE (=1-hazard ratio)×100%). OCV effectiveness estimates obtained using the TND (Matlab: 51%, 95% CI:37-62%; Kolkata: 67%, 95% CI:57-75%) were similar to the cohort analyses of these RCTs (Matlab: 52%, 95% CI:43-60% and Kolkata: 66%, 95% CI:55-74%). The TND VE estimate for the Zanzibar data was 94% (95% CI:84-98%) compared with 82% (95% CI:58-93%) in the cohort analysis. After adjusting for residual confounding in the cohort analysis of the Zanzibar study, using a bias indicator condition, we observed almost no difference in the two estimates. Our findings suggest that the TND is a valid approach for evaluating OCV effectiveness in routine vaccination programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of exposure assessment and parameterization on exposure response. Aspects of epidemiologic cohort analysis using the Libby Amphibole asbestos worker cohort.

PubMed

Bateson, Thomas F; Kopylev, Leonid

2015-01-01

Recent meta-analyses of occupational epidemiology studies identified two important exposure data quality factors in predicting summary effect measures for asbestos-associated lung cancer mortality risk: sufficiency of job history data and percent coverage of work history by measured exposures. The objective was to evaluate different exposure parameterizations suggested in the asbestos literature using the Libby, MT asbestos worker cohort and to evaluate influences of exposure measurement error caused by historically estimated exposure data on lung cancer risks. Focusing on workers hired after 1959, when job histories were well-known and occupational exposures were predominantly based on measured exposures (85% coverage), we found that cumulative exposure alone, and with allowance of exponential decay, fit lung cancer mortality data similarly. Residence-time-weighted metrics did not fit well. Compared with previous analyses based on the whole cohort of Libby workers hired after 1935, when job histories were less well-known and exposures less frequently measured (47% coverage), our analyses based on higher quality exposure data yielded an effect size as much as 3.6 times higher. Future occupational cohort studies should continue to refine retrospective exposure assessment methods, consider multiple exposure metrics, and explore new methods of maintaining statistical power while minimizing exposure measurement error.

Do Stem Taper Microgrooves Influence Taper Corrosion in Total Hip Arthroplasty? A Matched Cohort Retrieval Study

PubMed Central

Arnholt, Christina M.; MacDonald, Daniel W.; Underwood, Richard; Guyer, Eric P.; Rimnac, Clare M.; Kurtz, Steven M.; Mont, Michael A.; Klein, Gregg; Lee, Gwo-Chin; Chen, Antonia F.; Hamlin, Brian; Cates, Harold; Malkani, Arthur; Kraay, Matthew

2017-01-01

Background Previous studies identified imprinting of the stem morphology onto the interior head bore, leading researchers to hypothesize an influence of taper topography on mechanically assisted crevice corrosion (MACC). The purpose of this study was to analyze whether micro-grooved stem tapers result in greater fretting corrosion damage than smooth stem tapers. Methods A matched cohort of 120 retrieved head-stem pairs from metal-on-polyethylene bearings was created controlling for implantation time, flexural rigidity, apparent length of engagement, and head size. There were two groups of 60 heads each, mated with either smooth or micro-grooved stem tapers. A high precision roundness machine was used to measure and categorize the surface morphology. Fretting corrosion damage at the head/neck junction was characterized using the Higgs-Goldberg scoring method. Fourteen of the most damaged heads, were analyzed for the maximum depth of material loss and focused ion beam (FIB) cross-sectioned to view oxide and base metal. Results Fretting corrosion damage was not different between the two cohorts at the femoral head (p = 0.14, Mann Whitney) or stem tapers (p = 0.35). There was no difference in the maximum depths of material loss between the cohorts (p = 0.71). Cross sectioning revealed contact damage, signs of micro-motion, and chromium rich oxide layers in both cohorts. Micro-groove imprinting did not appear to have a different effect on the fretting corrosion behavior. Conclusion The results of this matched cohort retrieval study do not support the hypothesis that taper surfaces with micro-grooved stems exhibit increased in vivo fretting corrosion damage or material release. PMID:28111124

The WISTAH hand study: A prospective cohort study of distal upper extremity musculoskeletal disorders

PubMed Central

2012-01-01

Background Few prospective cohort studies of distal upper extremity musculoskeletal disorders have been performed. Past studies have provided somewhat conflicting evidence for occupational risk factors and have largely reported data without adjustments for many personal and psychosocial factors. Methods/design A multi-center prospective cohort study was incepted to quantify risk factors for distal upper extremity musculoskeletal disorders and potentially develop improved methods for analyzing jobs. Disorders to analyze included carpal tunnel syndrome, lateral epicondylalgia, medial epicondylalgia, trigger digit, deQuervain’s stenosing tenosynovitis and other tendinoses. Workers have thus far been enrolled from 17 different employment settings in 3 diverse US states and performed widely varying work. At baseline, workers undergo laptop administered questionnaires, structured interviews, two standardized physical examinations and nerve conduction studies to ascertain demographic, medical history, psychosocial factors and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of musculoskeletal disorders. Repeat nerve conduction studies are performed for those with symptoms of tingling and numbness in the prior six months. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. Case definitions have been established. Point prevalence of carpal tunnel syndrome is a combination of paraesthesias in at least two median nerve-served digits plus an abnormal nerve conduction study at baseline. The lifetime cumulative incidence of carpal tunnel syndrome will also include those with a past history of carpal tunnel syndrome. Incident cases will exclude those with either a past history or prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression. Discussion A prospective cohort study of distal upper extremity musculoskeletal disorders is underway and has successfully enrolled over 1,000 workers to date. PMID:22672216

Using the entire history in the analysis of nested case cohort samples.

PubMed

Rivera, C L; Lumley, T

2016-08-15

Countermatching designs can provide more efficient estimates than simple matching or case-cohort designs in certain situations such as when good surrogate variables for an exposure of interest are available. We extend pseudolikelihood estimation for the Cox model under countermatching designs to models where time-varying covariates are considered. We also implement pseudolikelihood with calibrated weights to improve efficiency in nested case-control designs in the presence of time-varying variables. A simulation study is carried out, which considers four different scenarios including a binary time-dependent variable, a continuous time-dependent variable, and the case including interactions in each. Simulation results show that pseudolikelihood with calibrated weights under countermatching offers large gains in efficiency if compared to case-cohort. Pseudolikelihood with calibrated weights yielded more efficient estimators than pseudolikelihood estimators. Additionally, estimators were more efficient under countermatching than under case-cohort for the situations considered. The methods are illustrated using the Colorado Plateau uranium miners cohort. Furthermore, we present a general method to generate survival times with time-varying covariates. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[Record linkage of the elderly in the national surveys on the geriatric intermediate care facility].

PubMed

Doi, T; Chen, B

1997-07-01

Geriatric intermediate care facility, GICF, have been established since 1986 in Japan. The term of 'intermediate' denotes a facility midpoint between a hospital and home, with a powerful rehabilitation function. The annual governmental survey on GICF has been applied to all GICFs in Japan since 1989. This survey is a cross-sectional-type survey. For evaluating the role of GICF, we considered a type of cohort study using these surveys for four years by means of a record linkage method. This method is possible, because subjects of a survey for any year become subjects in the survey of the following year, if they have been in a GICF for more than one year. In this paper, for the purpose of preparing for a study of the role of GICF, we report some results about a record linkage for these surveys, and two continuing rates were calculated for these cohorts. Sources were personal records in 1989 to 1992 gathered by The National Survey on GICF in Japan. The record linkage method is as follows. We divided the annual personal records into several files by both the periods of the last admission and the survey year. Three cohorts, i.e. a cohort-89, a cohort-90 and a cohort-91 for persons for whom the first survey was 1989, 1990 and 1991, respectively are thus obtained. Next, we identified individuals from the annual files in each cohort. As personal names were not available, we identified individuals by sex, birth date, date of admission and facility number by the use of a personal computer and a FORTRAN program. Results were as follows. 1. Multiple matched persons were few (0.5% or less), and identification rates were 90% or more, despite the fact that basic linking variables were used. 2. Continuing rates were about 40% and decreased with new cohorts, while those of a fixed cohort were increased as length of stay increased. These reveal that recent admissions who stay continuously at a GICF were decreasing, but the longer the period for which the elderly stays at a GICF, the less possibility that he will be discharged. 3. Between record agreement rates for individuals over two years for unchangeable characteristics such as a place before admission which are expected to be 100% were about 80%. 4. A record linkage method appears to be useful for calculating continuing rates classified by any attribute.

Mapping of HLA- DQ haplotypes in a group of Danish patients with celiac disease.

PubMed

Lund, Flemming; Hermansen, Mette N; Pedersen, Merete F; Hillig, Thore; Toft-Hansen, Henrik; Sölétormos, György

2015-10-01

A cost-effective identification of HLA- DQ risk haplotypes using the single nucleotide polymorphism (SNP) technique has recently been applied in the diagnosis of celiac disease (CD) in four European populations. The objective of the study was to map risk HLA- DQ haplotypes in a group of Danish CD patients using the SNP technique. Cohort A: Among 65 patients with gastrointestinal symptoms we compared the HLA- DQ2 and HLA- DQ8 risk haplotypes obtained by the SNP technique (method 1) with results based on a sequence specific primer amplification technique (method 2) and a technique used in an assay from BioDiagene (method 3). Cohort B: 128 patients with histologically verified CD were tested for CD risk haplotypes (method 1). Patients with negative results were further tested for sub-haplotypes of HLA- DQ2 (methods 2 and 3). Cohort A: The three applied methods provided the same HLA- DQ2 and HLA- DQ8 results among 61 patients. Four patients were negative for the HLA- DQ2 and HLA- DQ8 haplotypes (method 1) but were positive for the HLA- DQ2.5-trans and HLA- DQ2.2 haplotypes (methods 2 and 3). Cohort B: A total of 120 patients were positive for the HLA- DQ2.5-cis and HLA- DQ8 haplotypes (method 1). The remaining seven patients were positive for HLA- DQ2.5-trans or HLA- DQ2.2 haplotypes (methods 2 and 3). One patient was negative with all three HLA methods. The HLA- DQ risk haplotypes were detected in 93.8% of the CD patients using the SNP technique (method 1). The sensitivity increased to 99.2% by combining methods 1 - 3.

Methods of epidemiology: evaluating the fat-breast cancer hypothesis--comparing dietary instruments and other developments.

PubMed

Freedman, Laurence S; Kipnis, Victor; Schatzkin, Arthur; Potischman, Nancy

2008-01-01

Results from several large cohort studies that were reported 10 to 20 years ago seemed to indicate that the hypothesized link between dietary fat intake and breast cancer risk was illusory. In this article, we review several strands of more recent evidence that have emerged. These include two studies comparing the performance of dietary instruments used to investigate the dietary fat- breast cancer hypothesis, a large randomized disease prevention trial, a more recent meta-analysis of nutritional cohort studies, and a very large nutritional cohort study. Each of the studies discussed in this article suggests that a modest but real association between fat intake and breast cancer is likely. If the association is causative, it would have important implications for public health strategies in reducing breast cancer incidence. The evidence is not yet conclusive, but additional follow-up in the randomized trial, as well as efforts to improve dietary assessment methodology for cohort studies, may be sufficient to provide a convincing answer.

Confounder summary scores when comparing the effects of multiple drug exposures.

PubMed

Cadarette, Suzanne M; Gagne, Joshua J; Solomon, Daniel H; Katz, Jeffrey N; Stürmer, Til

2010-01-01

Little information is available comparing methods to adjust for confounding when considering multiple drug exposures. We compared three analytic strategies to control for confounding based on measured variables: conventional multivariable, exposure propensity score (EPS), and disease risk score (DRS). Each method was applied to a dataset (2000-2006) recently used to examine the comparative effectiveness of four drugs. The relative effectiveness of risedronate, nasal calcitonin, and raloxifene in preventing non-vertebral fracture, were each compared to alendronate. EPSs were derived both by using multinomial logistic regression (single model EPS) and by three separate logistic regression models (separate model EPS). DRSs were derived and event rates compared using Cox proportional hazard models. DRSs derived among the entire cohort (full cohort DRS) was compared to DRSs derived only among the referent alendronate (unexposed cohort DRS). Less than 8% deviation from the base estimate (conventional multivariable) was observed applying single model EPS, separate model EPS or full cohort DRS. Applying the unexposed cohort DRS when background risk for fracture differed between comparison drug exposure cohorts resulted in -7 to + 13% deviation from our base estimate. With sufficient numbers of exposed and outcomes, either conventional multivariable, EPS or full cohort DRS may be used to adjust for confounding to compare the effects of multiple drug exposures. However, our data also suggest that unexposed cohort DRS may be problematic when background risks differ between referent and exposed groups. Further empirical and simulation studies will help to clarify the generalizability of our findings.

Early Prediction of Intensive Care Unit-Acquired Weakness: A Multicenter External Validation Study.

PubMed

Witteveen, Esther; Wieske, Luuk; Sommers, Juultje; Spijkstra, Jan-Jaap; de Waard, Monique C; Endeman, Henrik; Rijkenberg, Saskia; de Ruijter, Wouter; Sleeswijk, Mengalvio; Verhamme, Camiel; Schultz, Marcus J; van Schaik, Ivo N; Horn, Janneke

2018-01-01

An early diagnosis of intensive care unit-acquired weakness (ICU-AW) is often not possible due to impaired consciousness. To avoid a diagnostic delay, we previously developed a prediction model, based on single-center data from 212 patients (development cohort), to predict ICU-AW at 2 days after ICU admission. The objective of this study was to investigate the external validity of the original prediction model in a new, multicenter cohort and, if necessary, to update the model. Newly admitted ICU patients who were mechanically ventilated at 48 hours after ICU admission were included. Predictors were prospectively recorded, and the outcome ICU-AW was defined by an average Medical Research Council score <4. In the validation cohort, consisting of 349 patients, we analyzed performance of the original prediction model by assessment of calibration and discrimination. Additionally, we updated the model in this validation cohort. Finally, we evaluated a new prediction model based on all patients of the development and validation cohort. Of 349 analyzed patients in the validation cohort, 190 (54%) developed ICU-AW. Both model calibration and discrimination of the original model were poor in the validation cohort. The area under the receiver operating characteristics curve (AUC-ROC) was 0.60 (95% confidence interval [CI]: 0.54-0.66). Model updating methods improved calibration but not discrimination. The new prediction model, based on all patients of the development and validation cohort (total of 536 patients) had a fair discrimination, AUC-ROC: 0.70 (95% CI: 0.66-0.75). The previously developed prediction model for ICU-AW showed poor performance in a new independent multicenter validation cohort. Model updating methods improved calibration but not discrimination. The newly derived prediction model showed fair discrimination. This indicates that early prediction of ICU-AW is still challenging and needs further attention.

Costs and Efficiency of Online and Offline Recruitment Methods: A Web-Based Cohort Study

PubMed Central

Riis, Anders H; Hatch, Elizabeth E; Wise, Lauren A; Nielsen, Marie G; Rothman, Kenneth J; Toft Sørensen, Henrik; Mikkelsen, Ellen M

2017-01-01

Background The Internet is widely used to conduct research studies on health issues. Many different methods are used to recruit participants for such studies, but little is known about how various recruitment methods compare in terms of efficiency and costs. Objective The aim of our study was to compare online and offline recruitment methods for Internet-based studies in terms of efficiency (number of recruited participants) and costs per participant. Methods We employed several online and offline recruitment methods to enroll 18- to 45-year-old women in an Internet-based Danish prospective cohort study on fertility. Offline methods included press releases, posters, and flyers. Online methods comprised advertisements placed on five different websites, including Facebook and Netdoktor.dk. We defined seven categories of mutually exclusive recruitment methods and used electronic tracking via unique Uniform Resource Locator (URL) and self-reported data to identify the recruitment method for each participant. For each method, we calculated the average cost per participant and efficiency, that is, the total number of recruited participants. Results We recruited 8252 study participants. Of these, 534 were excluded as they could not be assigned to a specific recruitment method. The final study population included 7724 participants, of whom 803 (10.4%) were recruited by offline methods, 3985 (51.6%) by online methods, 2382 (30.8%) by online methods not initiated by us, and 554 (7.2%) by other methods. Overall, the average cost per participant was €6.22 for online methods initiated by us versus €9.06 for offline methods. Costs per participant ranged from €2.74 to €105.53 for online methods and from €0 to €67.50 for offline methods. Lowest average costs per participant were for those recruited from Netdoktor.dk (€2.99) and from Facebook (€3.44). Conclusions In our Internet-based cohort study, online recruitment methods were superior to offline methods in terms of efficiency (total number of participants enrolled). The average cost per recruited participant was also lower for online than for offline methods, although costs varied greatly among both online and offline recruitment methods. We observed a decrease in the efficiency of some online recruitment methods over time, suggesting that it may be optimal to adopt multiple online methods. PMID:28249833

Non-cancer morbidity among Estonian Chernobyl cleanup workers: a register-based cohort study

PubMed Central

Rahu, Kaja; Bromet, Evelyn J; Hakulinen, Timo; Auvinen, Anssi; Uusküla, Anneli; Rahu, Mati

2014-01-01

Objective To examine non-cancer morbidity in the Estonian Chernobyl cleanup workers cohort compared with the population sample with special attention to radiation-related diseases and mental health disorders. Design Register-based cohort study. Setting Estonia. Participants An exposed cohort of 3680 men (cleanup workers) and an unexposed cohort of 7631 men (population sample) were followed from 2004 to 2012 through the Population Registry and Health Insurance Fund database. Methods Morbidity in the exposed cohort compared with the unexposed controls was estimated in terms of rate ratio (RR) with 95% CIs using Poisson regression models. Results Elevated morbidity in the exposed cohort was found for diseases of the nervous system, digestive system, musculoskeletal system, ischaemic heart disease and for external causes. The most salient excess risk was observed for thyroid diseases (RR=1.69; 95% CI 1.38 to 2.07), intentional self-harm (RR=1.47; 95% CI 1.04 to 2.09) and selected alcohol-related diagnoses (RR=1.25; 95% CI 1.12 to 1.39). No increase in morbidity for stress reactions, depression, headaches or sleep disorders was detected. Conclusions No obvious excess morbidity consistent with biological effects of radiation was seen in the exposed cohort, with the possible exception of benign thyroid diseases. Increased alcohol-induced morbidity may reflect alcohol abuse, and could underlie some of the higher morbidity rates. Mental disorders in the exposed cohort were probably under-reported. The future challenge will be to study mental and physical comorbidities in the Chernobyl cleanup workers cohort. PMID:24833681

Risk of relapse after natalizumab withdrawal

PubMed Central

Vukusic, Sandra; Casey, Romain; Debard, Nadine; Stankoff, Bruno; Mrejen, Serge; Uhry, Zoe; Van Ganse, Eric; Castot, Anne; Clanet, Michel; Lubetzki, Catherine; Confavreux, Christian

2016-01-01

Objective: To assess disease activity within 12 months after natalizumab (NZ) discontinuation in a large French postmarketing cohort. Methods: In France, patients exposed at least once to NZ were included in the TYSEDMUS observational and multicenter cohort, part of the French NZ Risk Management Plan. Clinical disease activity during the year following NZ discontinuation was assessed in this cohort. Time to first relapse after NZ stop was analyzed using Kaplan-Meier method and potentially associated factors were studied using a multivariate Cox model. Results: Out of the 4,055 patients with multiple sclerosis (MS) included in TYSEDMUS, 1,253 discontinued NZ and 715 of them had relevant data for our study. The probability of relapse within the year after NZ stop was estimated at 45% (95% confidence interval 0.41–0.49). Conclusions: This large and systematic survey of patients with MS after NZ withdrawal allows quantifying the risk of increased disease activity following treatment discontinuation. This study provides large-scale, multicenter, systematic data after NZ cessation in real-life settings. PMID:27844037

Impact of nurse-targeted care on HIV outcomes among immunocompromised persons: a before-after study in Uganda

PubMed Central

Kiragga, Agnes N.; Nalintya, Elizabeth; Morawski, Bozena M.; Kigozi, Joanita; Park, Benjamin J.; Kaplan, Jonathan E.; Boulware, David R.; Meya, David B.; Manabe, Yukari C.

2016-01-01

Introduction Improving HIV outcomes among severely immunocompromised HIV-infected persons who have increased morbidity and mortality remains an important issue in sub-Saharan Africa. We sought to evaluate the impact of targeted clinic- based nurse care on ART initiation and retention among severely immunocompromised HIV-infected persons. Methods The study included ART-naïve patients with CD4<100 cells/μL registered in seven urban clinics in Kampala, Uganda. Data were retrospectively collected on patients enrolled from July to December 2011 (routine care cohort). Between July 2012 and September 2013, one additional nurse per clinic was hired (nurse counselor cohort) to identify new patients, expedite ART initiation and trace those loss-to-follow-up. We compared time to ART initiation and 6-month retention in care between cohorts and used a generalized linear model to estimate the relative risk of retention. Results The study included 258 patients in the routine care cohort and 593 in the nurse counselor cohort. The proportion of patients who initiated ART increased from 190 (73.6%) in the routine care cohort to 506 (85.3%) in the nurse counselor cohort (p<0.001). At 6 months, 62% of the routine care cohort were retained in care versus 76% in the nurse counselor cohort (p=0.001). A 21% increase in likelihood of retention in the nurse counselor cohort (relative risk 1.21, 95% CI, 1.09–1.34) compared with the routine care cohort was observed. Conclusion Implementation of targeted nurse–led care of severely immunocompromised HIV-infected patients in public outpatient health care facilities resulted in decreased time to ART initiation and increased retention. PMID:27003494

Violent Crime Victimization Increases the Risk of Nursing Home Placement in Older Adults

ERIC Educational Resources Information Center

Lachs, Mark; Bachman, Ronet; Williams, Christianna S.; Kossack, Alice; Bove, Carolyn; O'Leary, John R.

2006-01-01

Purpose: We estimate the independent contribution of crime victimization to nursing home placement in a cohort of older adults who were community dwelling at baseline. Design and Methods: The data come from an observational cohort study of 2,321 community-residing older adults who were members of the New Haven Established Populations for…

Nonparametric evaluation of birth cohort trends in disease rates.

PubMed

Tarone, R E; Chu, K C

2000-01-01

Although interpretation of age-period-cohort analyses is complicated by the non-identifiability of maximum likelihood estimates, changes in the slope of the birth-cohort effect curve are identifiable and have potential aetiologic significance. A nonparametric test for a change in the slope of the birth-cohort trend has been developed. The test is a generalisation of the sign test and is based on permutational distributions. A method for identifying interactions between age and calendar-period effects is also presented. The nonparametric method is shown to be powerful in detecting changes in the slope of the birth-cohort trend, although its power can be reduced considerably by calendar-period patterns of risk. The method identifies a previously unidentified decrease in the birth-cohort risk of lung-cancer mortality from 1912 to 1919, which appears to reflect a reduction in the initiation of smoking by young men at the beginning of the Great Depression (1930s). The method also detects an interaction between age and calendar period in leukemia mortality rates, reflecting the better response of children to chemotherapy. The proposed nonparametric method provides a data analytic approach, which is a useful adjunct to log-linear Poisson analysis of age-period-cohort models, either in the initial model building stage, or in the final interpretation stage.

The Nightingale study: rationale, study design and baseline characteristics of a prospective cohort study on shift work and breast cancer risk among nurses

PubMed Central

2014-01-01

Background Evidence for the carcinogenicity of shift work in humans is limited because of significant heterogeneity of the results, thus more in-depth research in needed. The Nightingale Study is a nationwide prospective cohort study on occupational exposures and risks of chronic diseases among female nurses and focuses on the potential association between shift work and risk of breast cancer. The study design, methods, and baseline characteristics of the cohort are described. Methods/Design The source population for the cohort comprised 18 to 65 year old women who were registered as having completed training to be a nurse in the nationwide register for healthcare professionals in the Netherlands. Eligible women were invited to complete a web-based questionnaire including full job history, a detailed section on all domains of shift work (shift system, cumulative exposure, and shift intensity) and potential confounding factors, and an informed consent form for linkage with national (disease) registries. Women were also asked to donate toenail clippings as a source of DNA for genetic analyses. Between October 6, 2011 and February 1, 2012, 31% of the 192,931 women who were invited to participate completed the questionnaire, yielding a sample size of 59,947 cohort members. The mean age of the participants was 46.9 year (standard deviation 11.0 years). Toenail clippings were provided by 23,439 participants (39%). Discussion Results from the Nightingale Study will contribute to the scientific evidence of potential shift work-related health risks among nurses and will help develop preventive measures and policy aimed at reducing these risks. PMID:24475944

Health Assessment Questionnaire disability progression in early rheumatoid arthritis: Systematic review and analysis of two inception cohorts

PubMed Central

Norton, Sam; Fu, Bo; Scott, David L.; Deighton, Chris; Symmons, Deborah P.M.; Wailoo, Allan J.; Tosh, Jonathan; Lunt, Mark; Davies, Rebecca; Young, Adam; Verstappen, Suzanne M.M

2014-01-01

Objective The Health Assessment Questionnaire is widely used for patients with inflammatory polyarthritis (IP) and its subset, rheumatoid arthritis (RA). In this study, we evaluated the progression of HAQ scores in RA (i) by systematically reviewing the published literature on the methods used to assess changes in functional disability over time and (ii) to study in detail HAQ progression in two large prospective observational studies from the UK. Methods Data from two large inception cohorts, ERAS and NOAR, were studied to determine trajectories of HAQ progression over time by applying latent class growth models (LCGMs) to each dataset separately. Age, sex, baseline DAS28, symptom duration, rheumatoid factor, fulfilment of the 1987 ACR criteria and socio-economic status (SES) were included as potential predictors of HAQ trajectory subgroup membership. Results The literature search identified 49 studies showing that HAQ progression has mainly been based on average changes in the total study population. In the HAQ progression study, a LCGM with four HAQ trajectory subgroups was selected as providing the best fit in both cohorts. In both the cohorts, older age, female sex, longer symptom duration, fulfilment of the 1987 ACR criteria, higher DAS28 and lower SES were associated with increased likelihood of membership of subgroups with worse HAQ progression. Conclusion Four distinct HAQ trajectory subgroups were derived from the ERAS and NOAR cohorts. The fact that the subgroups identified were nearly identical supports their validity. Identifying distinct groups of patients who are at risk of poor functional outcome may help to target therapy to those who are most likely to benefit. PMID:24925692

The MANGUA Project: A Population-Based HIV Cohort in Guatemala

PubMed Central

García, Juan Ignacio; Samayoa, Blanca; Sabidó, Meritxell; Prieto, Luis Alberto; Nikiforov, Mikhail; Pinzón, Rodolfo; Santa Marina de León, Luis Roberto; Ortiz, José Fernando; Ponce, Ernesto; Mejía, Carlos Rodolfo; Arathoon, Eduardo; Casabona, Jordi; Study Group, The Mangua Cohort

2015-01-01

Introduction. The MANGUA cohort is an ongoing multicenter, observational study of people living with HIV/AIDS in Guatemala. The cohort is based on the MANGUA application which is an electronic database to capture essential data from the medical records of HIV patients in care. Methods. The cohort enrolls HIV-positive adults ≥16 years of age. A predefined set of sociodemographic, behavioral, clinical, and laboratory data are registered at entry to the cohort study. Results. As of October 1st, 2012, 21 697 patients had been included in the MANGUA cohort (median age: 33 years, 40.3% female). At enrollment 74.1% had signs of advanced HIV infection and only 56.3% had baseline CD4 cell counts. In the first 12 months after starting antiretroviral treatment 26.9% (n = 3938) of the patients were lost to the program. Conclusions. The implementation of a cohort of HIV-positive patients in care in Guatemala is feasible and has provided national HIV indicators to monitor and evaluate the HIV epidemic. The identified percentages of late presenters and high rates of LTFU will help the Ministry to target their current efforts in improving access to diagnosis and care. PMID:26425365

The MANGUA Project: A Population-Based HIV Cohort in Guatemala.

PubMed

García, Juan Ignacio; Samayoa, Blanca; Sabidó, Meritxell; Prieto, Luis Alberto; Nikiforov, Mikhail; Pinzón, Rodolfo; Santa Marina de León, Luis Roberto; Ortiz, José Fernando; Ponce, Ernesto; Mejía, Carlos Rodolfo; Arathoon, Eduardo; Casabona, Jordi; Study Group, The Mangua Cohort

2015-01-01

Introduction. The MANGUA cohort is an ongoing multicenter, observational study of people living with HIV/AIDS in Guatemala. The cohort is based on the MANGUA application which is an electronic database to capture essential data from the medical records of HIV patients in care. Methods. The cohort enrolls HIV-positive adults ≥16 years of age. A predefined set of sociodemographic, behavioral, clinical, and laboratory data are registered at entry to the cohort study. Results. As of October 1st, 2012, 21 697 patients had been included in the MANGUA cohort (median age: 33 years, 40.3% female). At enrollment 74.1% had signs of advanced HIV infection and only 56.3% had baseline CD4 cell counts. In the first 12 months after starting antiretroviral treatment 26.9% (n = 3938) of the patients were lost to the program. Conclusions. The implementation of a cohort of HIV-positive patients in care in Guatemala is feasible and has provided national HIV indicators to monitor and evaluate the HIV epidemic. The identified percentages of late presenters and high rates of LTFU will help the Ministry to target their current efforts in improving access to diagnosis and care.

Trends in the incidence of dementia: design and methods in the Alzheimer Cohorts Consortium.

PubMed

Chibnik, Lori B; Wolters, Frank J; Bäckman, Kristoffer; Beiser, Alexa; Berr, Claudine; Bis, Joshua C; Boerwinkle, Eric; Bos, Daniel; Brayne, Carol; Dartigues, Jean-Francois; Darweesh, Sirwan K L; Debette, Stephanie; Davis-Plourde, Kendra L; Dufouil, Carole; Fornage, Myriam; Grasset, Leslie; Gudnason, Vilmundur; Hadjichrysanthou, Christoforos; Helmer, Catherine; Ikram, M Arfan; Ikram, M Kamran; Kern, Silke; Kuller, Lewis H; Launer, Lenore; Lopez, Oscar L; Matthews, Fiona; Meirelles, Osorio; Mosley, Thomas; Ower, Alison; Psaty, Bruce M; Satizabal, Claudia L; Seshadri, Sudha; Skoog, Ingmar; Stephan, Blossom C M; Tzourio, Christophe; Waziry, Reem; Wong, Mei Mei; Zettergren, Anna; Hofman, Albert

2017-10-01

Several studies have reported a decline in incidence of dementia which may have large implications for the projected burden of disease, and provide important guidance to preventive efforts. However, reports are conflicting or inconclusive with regard to the impact of gender and education with underlying causes of a presumed declining trend remaining largely unidentified. The Alzheimer Cohorts Consortium aggregates data from nine international population-based cohorts to determine changes in the incidence of dementia since 1990. We will employ Poisson regression models to calculate incidence rates in each cohort and Cox proportional hazard regression to compare 5-year cumulative hazards across study-specific epochs. Finally, we will meta-analyse changes per decade across cohorts, and repeat all analysis stratified by sex, education and APOE genotype. In all cohorts combined, there are data on almost 69,000 people at risk of dementia with the range of follow-up years between 2 and 27. The average age at baseline is similar across cohorts ranging between 72 and 77. Uniting a wide range of disease-specific and methodological expertise in research teams, the first analyses within the Alzheimer Cohorts Consortium are underway to tackle outstanding challenges in the assessment of time-trends in dementia occurrence.

Attrition Bias in a U.S. Internet Survey of Alcohol Use Among College Freshmen*

PubMed Central

McCoy, Thomas P.; Ip, Edward H.; Blocker, Jill N.; Champion, Heather; Rhodes, Scott D.; Wagoner, Kimberly G.; Mitra, Ananda; Wolfson, Mark

2009-01-01

Objective: Attrition bias is an important issue in survey research on alcohol, tobacco, and other drug use. The issue is even more salient for Internet studies, because these studies often have higher rates of attrition than face-to-face or telephone surveys, and there is limited research examining the issue in the field of drug usage, specifically for college underclassmen. This study assessed whether measures of high-risk drinking and alcohol-related consequences were related to attrition groups (“stayers” or “leavers”) in a cohort of college freshmen. Method: Data were collected in 2003 and 2004 from 2,144 first-year college students at 10 universities in the southeastern United States. Demographics, indicators of high-risk drinking, and alcohol-related consequences were compared between cohort stayers and leavers in statistical analyses using two methods. Results: Analyses indicated that cohort leavers reported significantly higher levels of high-risk drinking (past-30-day heavy episodic drinking, weekly drunkenness) and past-30-day smoking but not significantly increased alcohol-related consequences. The directionality of bias was modestly consistent across outcomes and comparison methods. Conclusions: The current study's findings suggest that intervention efforts to reduce smoking or high-risk drinking need to consider attrition bias during study follow-up or account for it in analyses. PMID:19515302

Using probabilistic record linkage methods to identify Australian Indigenous women on the Queensland Pap Smear Register: the National Indigenous Cervical Screening Project

PubMed Central

Diaz, Abbey; Baade, Peter; Garvey, Gail; Cunningham, Joan; Brotherton, Julia M L; Canfell, Karen; Valery, Patricia C; O'Connell, Dianne L; Taylor, Catherine; Moore, Suzanne P; Condon, John R

2016-01-01

Objective To evaluate the feasibility and reliability of record linkage of existing population-based data sets to determine Indigenous status among women receiving Pap smears. This method may allow for the first ever population measure of Australian Indigenous women's cervical screening participation rates. Setting/participants A linked data set of women aged 20–69 in the Queensland Pap Smear Register (PSR; 1999–2011) and Queensland Cancer Registry (QCR; 1997–2010) formed the Initial Study Cohort. Two extracts (1995–2011) were taken from Queensland public hospitals data (Queensland Hospital Admitted Patient Data Collection, QHAPDC) for women, aged 20–69, who had ever been identified as Indigenous (extract 1) and had a diagnosis or procedure code relating to cervical cancer (extract 2). The Initial Study Cohort was linked to extract 1, and women with cervical cancer in the initial cohort were linked to extract 2. Outcome measures The proportion of women in the Initial Cohort who linked with the extracts (true -pairs) is reported, as well as the proportion of potential pairs that required clerical review. After assigning Indigenous status from QHAPDC to the PSR, the proportion of women identified as Indigenous was calculated using 4 algorithms, and compared. Results There were 28 872 women (2.1%) from the Initial Study Cohort who matched to an ever Indigenous record in extract 1 (n=76 831). Women with cervical cancer in the Initial Study Cohort linked to 1385 (71%) records in extract 2. The proportion of Indigenous women ranged from 2.00% to 2.08% when using different algorithms to define Indigenous status. The Final Study Cohort included 1 372 823 women (PSR n=1 374 401; QCR n=1955), and 5 062 118 records. Conclusions Indigenous status in Queensland cervical screening data was successfully ascertained through record linkage, allowing for the crucial assessment of the current cervical screening programme for Indigenous women. Our study highlights the need to include Indigenous status on Pap smear request and report forms in any renewed and redesigned cervical screening programme in Australia. PMID:26873047

Rationale, design, and methods for Canadian alliance for healthy hearts and minds cohort study (CAHHM) - a Pan Canadian cohort study.

PubMed

Anand, Sonia S; Tu, Jack V; Awadalla, Philip; Black, Sandra; Boileau, Catherine; Busseuil, David; Desai, Dipika; Després, Jean-Pierre; de Souza, Russell J; Dummer, Trevor; Jacquemont, Sébastien; Knoppers, Bartha; Larose, Eric; Lear, Scott A; Marcotte, Francois; Moody, Alan R; Parker, Louise; Poirier, Paul; Robson, Paula J; Smith, Eric E; Spinelli, John J; Tardif, Jean-Claude; Teo, Koon K; Tusevljak, Natasa; Friedrich, Matthias G

2016-07-27

The Canadian Alliance for Healthy Hearts and Minds (CAHHM) is a pan-Canadian, prospective, multi-ethnic cohort study being conducted in Canada. The overarching objective of the CAHHM is to understand the association of socio-environmental and contextual factors (such as societal structure, activity, nutrition, social and tobacco environments, and access to health services) with cardiovascular risk factors, subclinical vascular disease, and cardiovascular and other chronic disease outcomes. Participants between 35 and 69 years of age are being recruited from existing cohorts and a new First Nations Cohort to undergo a detailed assessment of health behaviours (including diet and physical activity), cognitive function, assessment of their local home and workplace environments, and their health services access and utilization. Physical measures including weight, height, waist/hip circumference, body fat percentage, and blood pressure are collected. In addition, eligible participants undergo magnetic resonance imaging (MRI) of the brain, heart, carotid artery and abdomen to detect early subclinical vascular disease and ectopic fat deposition. CAHHM is a prospective cohort study designed to investigate the impact of community level factors, individual health behaviours, and access to health services, on cognitive function, subclinical vascular disease, fat distribution, and the development of chronic diseases among adults living in Canada.

Impact of organised mammography screening on breast cancer mortality in a case–control and cohort study

PubMed Central

Heinävaara, Sirpa; Sarkeala, Tytti; Anttila, Ahti

2016-01-01

Background: The usefulness of case–control studies has been questioned. Our aim was to evaluate the long-term effect of screening on breast cancer mortality within the population-based mammography programme in Finland using a case–control design, and to compare the analyses with the earlier cohort study. Methods: The cases were women invited to screening, diagnosed and died from breast cancer in 1992–2011 while being 50–84 years at death. We chose 10 controls for each case with non-restrictive eligibility criteria. Our data included 1907 cases and 18 978 matched controls. We analysed associations between the screening participation and the risk of breast cancer death using the conditional Cox proportional hazards model. The effect estimates were corrected for self-selection bias. Results: An overall effect of screening was 0.67 (95% confidence interval (CI): 0.49–0.90), and that remained unchanged over time. Analyses with matching criteria comparable to the cohort study yielded an effect (0.70, 95% CI: 0.49–1.00) in 1992–2003 similar to that of the previous cohort analysis (0.72, 95% CI: 0.56–0.88). Conclusions: Organised mammography screening decreases mortality from breast cancer by 33% among the participants. If made comparable, a case–cohort study can yield effect estimates similar to a cohort study. PMID:27010748

Systems Biology Methods for Alzheimer's Disease Research Toward Molecular Signatures, Subtypes, and Stages and Precision Medicine: Application in Cohort Studies and Trials.

PubMed

Castrillo, Juan I; Lista, Simone; Hampel, Harald; Ritchie, Craig W

2018-01-01

Alzheimer's disease (AD) is a complex multifactorial disease, involving a combination of genomic, interactome, and environmental factors, with essential participation of (a) intrinsic genomic susceptibility and (b) a constant dynamic interplay between impaired pathways and central homeostatic networks of nerve cells. The proper investigation of the complexity of AD requires new holistic systems-level approaches, at both the experimental and computational level. Systems biology methods offer the potential to unveil new fundamental insights, basic mechanisms, and networks and their interplay. These may lead to the characterization of mechanism-based molecular signatures, and AD hallmarks at the earliest molecular and cellular levels (and beyond), for characterization of AD subtypes and stages, toward targeted interventions according to the evolving precision medicine paradigm. In this work, an update on advanced systems biology methods and strategies for holistic studies of multifactorial diseases-particularly AD-is presented. This includes next-generation genomics, neuroimaging and multi-omics methods, experimental and computational approaches, relevant disease models, and latest genome editing and single-cell technologies. Their progressive incorporation into basic research, cohort studies, and trials is beginning to provide novel insights into AD essential mechanisms, molecular signatures, and markers toward mechanism-based classification and staging, and tailored interventions. Selected methods which can be applied in cohort studies and trials, with the European Prevention of Alzheimer's Dementia (EPAD) project as a reference example, are presented and discussed.

Blood-based NfL

PubMed Central

Janelidze, Shorena; Hall, Sara; Magdalinou, Nadia; Lees, Andrew J.; Andreasson, Ulf; Norgren, Niklas; Linder, Jan; Forsgren, Lars; Constantinescu, Radu; Zetterberg, Henrik; Blennow, Kaj

2017-01-01

Objective: To determine if blood neurofilament light chain (NfL) protein can discriminate between Parkinson disease (PD) and atypical parkinsonian disorders (APD) with equally high diagnostic accuracy as CSF NfL, and can therefore improve the diagnostic workup of parkinsonian disorders. Methods: The study included 3 independent prospective cohorts: the Lund (n = 278) and London (n = 117) cohorts, comprising healthy controls and patients with PD, progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), and multiple system atrophy (MSA), as well as an early disease cohort (n = 109) of patients with PD, PSP, MSA, or CBS with disease duration ≤3 years. Blood NfL concentration was measured using an ultrasensitive single molecule array (Simoa) method, and the diagnostic accuracy to distinguish PD from APD was investigated. Results: We found strong correlations between blood and CSF concentrations of NfL (ρ ≥ 0.73–0.84, p ≤ 0.001). Blood NfL was increased in patients with MSA, PSP, and CBS (i.e., all APD groups) when compared to patients with PD as well as healthy controls in all cohorts (p < 0.001). Furthermore, in the Lund cohort, blood NfL could accurately distinguish PD from APD (area under the curve [AUC] 0.91) with similar results in both the London cohort (AUC 0.85) and the early disease cohort (AUC 0.81). Conclusions: Quantification of blood NfL concentration can be used to distinguish PD from APD. Blood-based NfL might consequently be included in the diagnostic workup of patients with parkinsonian symptoms in both primary care and specialized clinics. Classification of evidence: This study provides Class III evidence that blood NfL levels discriminate between PD and APD. PMID:28179466

Association between use of pre-hospital ECG and 30-day mortality: A large cohort study of patients experiencing chest pain.

PubMed

Rawshani, Nina; Rawshani, Araz; Gelang, Carita; Herlitz, Johan; Bång, Angela; Andersson, Jan-Otto; Gellerstedt, Martin

2017-12-01

In the assessment of patients with chest pain, there is support for the use of pre-hospital ECG in the literature and in the care guidelines. Using propensity score methods, we aim to examine whether the mere acquisition of a pre-hospital ECG among patients with chest pain affects the outcome (30-day mortality). The association between pre-hospital ECG and 30-day mortality was studied in the overall cohort (n=13151), as well as in the one-to-one matched cohort with 2524 patients not examined with pre-hospital ECG and 2524 patients examined with pre-hospital ECG. In the overall cohort, 21% (n=2809) did not undergo an ECG tracing in the pre-hospital setting. Among those who had pain during transport, 14% (n=1159) did not undergo a pre-hospital ECG while 32% (n=1135) of those who did not have pain underwent an ECG tracing. In the overall cohort, the OR for 30-day mortality in patients who had a pre-hospital ECG, as compared with those who did not, was 0.63 (95% CI 0.05-0.79; p<0.001). In the matched cohort, the OR was 0.65 (95% CI 0.49-0.85; p<0.001). Using the propensity score, in the overall cohort, the corresponding HR was 0.65 (95% CI 0.58-0.74). Using propensity score methods, we provide real-world data demonstrating that the adjusted risk of death was considerably lower among the cases in whoma pre-hospital ECG was used. The PH-ECG is underused among patients with chest discomfort and the mere acquisition of a pre-hospital ECG may reduce mortality. Copyright © 2017 Elsevier B.V. All rights reserved.

LONGITUDINAL COHORT METHODS STUDIES

EPA Science Inventory

Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Exposure classification for occupational studies is relatively easy compared to predicting residential childhood exposures. Recent NHEXAS (Maryland) study articl...

The value of KRAS mutation testing with CEA for the diagnosis of pancreatic mucinous cysts

PubMed Central

Kadayifci, Abdurrahman; Al-Haddad, Mohammad; Atar, Mustafa; Dewitt, John M.; Forcione, David G.; Sherman, Stuart; Casey, Brenna W.; Fernandez-del Castillo, Carlos; Schmidt, C. Max; Pitman, Martha B.; Brugge, William R.

2016-01-01

Background and aims: Pancreatic cyst fluid (PCF) CEA has been shown to be the most accurate preoperative test for detection of cystic mucinous neoplasms (CMNs). This study aimed to assess the added value of PCF KRAS mutational analysis to CEA for diagnosis of CMNs. Patients and methods: This is a retrospective study of prospectively collected endoscopic ultrasonography (EUS) fine-needle aspiration (FNA) data. KRAS mutation was determined by direct sequencing or equivalent methods. Cysts were classified histologically (surgical cohort) or by clinical (EUS or FNA) findings (clinical cohort). Performance characteristics of KRAS, CEA and their combination for detection of a cystic mucinous neoplasm (CMN) and malignancy were calculated. Results: The study cohort consisted of 943 patients: 147 in the surgical cohort and 796 in the clinical cohort. Overall, KRAS and CEA each had high specificity (100 % and 93.2 %), but low sensitivity (48.3 % and 56.3 %) for the diagnosis of a CMN. The positivity of KRAS or CEA increased the diagnostic accuracy (80.8 %) and AUC (0.84) significantly compared to KRAS (65.3 % and 0.74) or CEA (65.8 % and 0.74) alone, but only in the clinical cohort (P < 0.0001 for both). KRAS mutation was significantly more frequent in malignant CMNs compared to histologically confirmed non-malignant CMNs (73 % vs. 37 %, P = 0.001). The negative predictive value of KRAS mutation was 77.6 % in differentiating non-malignant cysts. Conclusions: The detection of a KRAS mutation in PCF is a highly specific test for mucinous cysts. It outperforms CEA for sensitivity in mucinous cyst diagnosis, but the data does not support its routine use. PMID:27092317

Mediators of Atherosclerosis in South Asians Living in America (MASALA) study: Objectives, Methods, and Cohort Description

PubMed Central

2013-01-01

Background South Asians (individuals from India, Pakistani, Bangladesh, Nepal, and Sri Lanka) have high rates of cardiovascular disease which cannot be explained by traditional risk factors. There are no prospective cohort studies investigating antecedents of cardiovascular disease in South Asians. Methods The Mediators of Atherosclerosis in South Asians Living in America (MASALA) study is investigating the prevalence, correlates and outcomes associated with subclinical cardiovascular disease (CVD) in a population-based sample of South Asian men and women between ages 40 – 79 years from two U.S. clinical field centers. This cohort is similar in methods and measures to the Multi-Ethnic Study of Atherosclerosis to allow for efficient cross-ethnic comparisons. Measurements obtained at the baseline examination include sociodemographic information, lifestyle and psychosocial factors, standard CVD risk factors, oral glucose tolerance testing, electrocardiogram, assessment of microalbuminuria, ankle and brachial blood pressures, carotid intima media wall thickness using ultrasonagraphy, coronary artery calcium measurement and abdominal visceral fat using computed tomography. Blood samples will be assayed for biochemical risk factors. Results Between October 2010 and March 2013 we enrolled 906 South Asians with mean age of 55±9 years, 46% women, 98% immigrants who have lived 27±11 years in the US. Conclusions The sociodemographic characteristics of this cohort are representative of US South Asians. Participants are being followed with annual telephone calls for identification of CVD events including acute myocardial infarction and other coronary heart disease, stroke, peripheral vascular disease, congestive heart failure, therapeutic interventions for CVD, and mortality. PMID:24194499

Intakes of caffeine, coffee and tea and risk of Amyotrophic Lateral Sclerosis: Results from five cohort studies

PubMed Central

Fondell, Elinor; O'Reilly, Éilis J.; Fitzgerald, Kathryn C.; Falcone, Guido J.; Kolonel, Laurence N.; Park, Yikyung; Gapstur, Susan M.; Ascherio, Alberto

2015-01-01

Objective Caffeine is thought to be neuroprotective by antagonizing the adenosine A2A receptors in the brain and thereby protecting motor neurons from excitotoxicity. We examined the association between consumption of caffeine, coffee and tea and risk of Amyotrophic Lateral Sclerosis (ALS). Methods Longitudinal analyses based on over 1 010 000 men and women in 5 large cohort studies [the Nurses’ Health Study, the Health Professionals Follow-up Study, the Cancer Prevention Study II Nutrition Cohort, the Multiethnic Cohort Study, and the National Institutes of Health – AARP Diet and Health Study]. Cohort-specific multivariable-adjusted risk ratios (RR) and 95% confidence intervals (CI) estimates of ALS incidence or death was estimated by Cox proportional hazards regression and pooled using random-effects models. Results A total of 1279 cases of ALS were documented during a mean of 18 years of follow-up. Caffeine intake was not associated with ALS risk; the pooled multivariable-adjusted RR comparing the highest to the lowest quintile of intake was 0.96 (95% CI 0.81-1.16). Similarly, neither coffee nor tea was associated with ALS risk. Conclusion The results of this large study do not support associations of caffeine or caffeinated beverages with ALS risk. PMID:25822002

Does Extended Preoperative Rehabilitation Influence Outcomes 2 Years After ACL Reconstruction?

PubMed Central

Failla, Mathew J.; Logerstedt, David S.; Grindem, Hege; Axe, Michael J.; Risberg, May Arna; Engebretsen, Lars; Huston, Laura J.; Spindler, Kurt P.; Snyder-Mackler, Lynn

2017-01-01

Background Rehabilitation before anterior cruciate ligament (ACL) reconstruction (ACLR) is effective at improving postoperative outcomes at least in the short term. Less is known about the effects of preoperative rehabilitation on functional outcomes and return-to-sport (RTS) rates 2 years after reconstruction. Purpose/Hypothesis The purpose of this study was to compare functional outcomes 2 years after ACLR in a cohort that underwent additional preoperative rehabilitation, including progressive strengthening and neuromuscular training after impairments were resolved, compared with a nonexperimental cohort. We hypothesized that the cohort treated with extended preoperative rehabilitation would have superior functional outcomes 2 years after ACLR. Study Design Cohort study; Level of evidence, 3. Methods This study compared outcomes after an ACL rupture in an international cohort (Delaware-Oslo ACL Cohort [DOC]) treated with extended preoperative rehabilitation, including neuromuscular training, to data from the Multicenter Orthopaedic Outcomes Network (MOON) cohort, which did not undergo extended preoperative rehabilitation. Inclusion and exclusion criteria from the DOC were applied to the MOON database to extract a homogeneous sample for comparison. Patients achieved knee impairment resolution before ACLR, and postoperative rehabilitation followed each cohort's respective criterion-based protocol. Patients completed the International Knee Documentation Committee (IKDC) subjective knee form and Knee injury and Osteoarthritis Outcome Score (KOOS) at enrollment and again 2 years after ACLR. RTS rates were calculated for each cohort at 2 years. Results After adjusting for baseline IKDC and KOOS scores, the DOC patients showed significant and clinically meaningful differences in IKDC and KOOS scores 2 years after ACLR. There was a significantly higher (P < .001) percentage of DOC patients returning to preinjury sports (72%) compared with those in the MOON cohort (63%). Conclusion The cohort treated with additional preoperative rehabilitation consisting of progressive strengthening and neuromuscular training, followed by a criterion-based postoperative rehabilitation program, had greater functional outcomes and RTS rates 2 years after ACLR. Preoperative rehabilitation should be considered as an addition to the standard of care to maximize functional outcomes after ACLR. PMID:27416993

A multi-analyte serum test for the detection of non-small cell lung cancer

PubMed Central

Farlow, E C; Vercillo, M S; Coon, J S; Basu, S; Kim, A W; Faber, L P; Warren, W H; Bonomi, P; Liptay, M J; Borgia, J A

2010-01-01

Background: In this study, we appraised a wide assortment of biomarkers previously shown to have diagnostic or prognostic value for non-small cell lung cancer (NSCLC) with the intent of establishing a multi-analyte serum test capable of identifying patients with lung cancer. Methods: Circulating levels of 47 biomarkers were evaluated against patient cohorts consisting of 90 NSCLC and 43 non-cancer controls using commercial immunoassays. Multivariate statistical methods were used on all biomarkers achieving statistical relevance to define an optimised panel of diagnostic biomarkers for NSCLC. The resulting biomarkers were fashioned into a classification algorithm and validated against serum from a second patient cohort. Results: A total of 14 analytes achieved statistical relevance upon evaluation. Multivariate statistical methods then identified a panel of six biomarkers (tumour necrosis factor-α, CYFRA 21-1, interleukin-1ra, matrix metalloproteinase-2, monocyte chemotactic protein-1 and sE-selectin) as being the most efficacious for diagnosing early stage NSCLC. When tested against a second patient cohort, the panel successfully classified 75 of 88 patients. Conclusions: Here, we report the development of a serum algorithm with high specificity for classifying patients with NSCLC against cohorts of various ‘high-risk' individuals. A high rate of false positives was observed within the cohort in which patients had non-neoplastic lung nodules, possibly as a consequence of the inflammatory nature of these conditions. PMID:20859284

Effectiveness of pharmacovigilance training of general practitioners: a retrospective cohort study in the Netherlands comparing two methods.

PubMed

Gerritsen, Roald; Faddegon, Hans; Dijkers, Fred; van Grootheest, Kees; van Puijenbroek, Eugène

2011-09-01

Spontaneous reporting is a cornerstone of pharmacovigilance. Unfamiliarity with the reporting of suspected adverse drug reactions (ADRs) is a major factor leading to not reporting these events. Medical education may promote more effective reporting. Numerous changes have been implemented in medical education over the last decade, with a shift in training methods from those aimed predominantly at the transfer of knowledge towards those that are more practice based and skill oriented. It is conceivable that these changes have an impact on pharmacovigilance training in vocational training programmes. Therefore, this study compares the effectiveness of a skill-oriented, practice-based pharmacovigilance training method, with a traditional, lecture-based pharmacovigilance training method in the vocational training of general practitioners (GPs). The traditional, lecture-based method is common practice in the Netherlands. The purpose of this study was to establish whether the use of a practice-based, skill-oriented method in pharmacovigilance training during GP traineeship leads to an increase of reported ADRs after completion of this traineeship, compared with a lecture-based method. We also investigated whether the applied training method has an impact on the documentation level of the reports and on the number of unlabelled events reported. A retrospective cohort study. The number of ADR reports submitted to the Netherlands Pharmacovigilance Centre Lareb (between January 2006 and October 2010) after completion of GP vocational training was compared between the two groups. Documentation level of the reports and the number of labelled/unlabelled events reported were also compared. The practice-based cohort reported 32 times after completion of training (124 subjects, 6.8 reports per 1000 months of follow-up; total follow-up of 4704 months). The lecture-based cohort reported 12 times after training (135 subjects, 2.1 reports per 1000 months of follow-up; total follow-up of 5824 months) [odds ratio 2.9; 95% CI 1.4, 6.1]. Reports from GPs with practice-based training had a better documentation grade than those from GPs with lecture-based training, and more often concerned unlabelled events. The practice-based method resulted in significantly more and better-documented reports and more often concerned unlabelled events than the lecture-based method. This effect persisted and did not appear to diminish over time.

Decreasing Sports Activity with Increasing Age? Findings from a 20-Year Longitudinal and Cohort Sequence Analysis

ERIC Educational Resources Information Center

Breuer, Christoph; Wicker, Pamela

2009-01-01

According to cross-sectional studies in sport science literature, decreasing sports activity with increasing age is generally assumed. In this paper, the validity of this assumption is checked by applying more effective methods of analysis, such as longitudinal and cohort sequence analyses. With the help of 20 years' worth of data records from the…

Childhood ADHD Is Strongly Associated with a Broad Range of Psychiatric Disorders during Adolescence: A Population-Based Birth Cohort Study

ERIC Educational Resources Information Center

Yoshimasu, Kouichi; Barbaresi, William J.; Colligan, Robert C.; Voigt, Robert G.; Killian, Jill M.; Weaver, Amy L.; Katusic, Slavica K.

2012-01-01

Background: To evaluate associations between attention-deficit/hyperactivity disorder (ADHD) and comorbid psychiatric disorders using research-identified incident cases of ADHD and population-based controls. Methods: Subjects included a birth cohort of all children born 1976-1982 remaining in Rochester, MN after age five (n = 5,718). Among them we…

Health impact of US military service in a large population-based military cohort: findings of the Millennium Cohort Study, 2001-2008

PubMed Central

2011-01-01

Background Combat-intense, lengthy, and multiple deployments in Iraq and Afghanistan have characterized the new millennium. The US military's all-volunteer force has never been better trained and technologically equipped to engage enemy combatants in multiple theaters of operations. Nonetheless, concerns over potential lasting effects of deployment on long-term health continue to mount and are yet to be elucidated. This report outlines how findings from the first 7 years of the Millennium Cohort Study have helped to address health concerns related to military service including deployments. Methods The Millennium Cohort Study was designed in the late 1990s to address veteran and public concerns for the first time using prospectively collected health and behavioral data. Results Over 150 000 active-duty, reserve, and National Guard personnel from all service branches have enrolled, and more than 70% of the first 2 enrollment panels submitted at least 1 follow-up survey. Approximately half of the Cohort has deployed in support of operations in Iraq and Afghanistan. Conclusion The Millennium Cohort Study is providing prospective data that will guide public health policymakers for years to come by exploring associations between military exposures and important health outcomes. Strategic studies aim to identify, reduce, and prevent adverse health outcomes that may be associated with military service, including those related to deployment. PMID:21281496

School District Enrollment Projections: A Comparison of Three Methods.

ERIC Educational Resources Information Center

Pettibone, Timothy J.; Bushan, Latha

This study assesses three methods of forecasting school enrollments: the cohort-sruvival method (grade progression), the statistical forecasting procedure developed by the Statistical Analysis System (SAS) Institute, and a simple ratio computation. The three methods were used to forecast school enrollments for kindergarten through grade 12 in a…

Cooking of meat and fish in Europe--results from the European Prospective Investigation into Cancer and Nutrition (EPIC).

PubMed

Rohrmann, S; Linseisen, J; Becker, N; Norat, T; Sinha, R; Skeie, G; Lund, E; Martínez, C; Barricarte, A; Mattisson, I; Berglund, G; Welch, A; Davey, G; Overvad, K; Tjønneland, A; Clavel-Chapelon, F; Kesse, E; Lotze, G; Klipstein-Grobusch, K; Vasilopoulou, E; Polychronopoulos, E; Pala, V; Celentano, E; Bueno-De-Mesquita, H B; Peeters, P H M; Riboli, E; Slimani, N

2002-12-01

There is epidemiologic evidence that the consumption of fried, grilled or barbecued meat and fish that are well-done or browned may be associated with an increased cancer risk. These high-temperature cooking methods are thought to be surrogates for mutagens and carcinogens produced in meat and fish, eg heterocyclic amines or polycyclic hydrocarbons. Since data on food cooking methods are scarce, the aim of this study was to describe the variation in meat and fish cooking methods in different parts of Europe. Using a standardized 24 h recall from a sub-sample of the EPIC cohort (35 644 persons, 35-75 y old), mean daily intake of meat and fish prepared by different cooking methods and the relative contribution of the cooking methods to the overall cooking of meat and fish was calculated. Whereas frying was more often noted in northern Europe, roasting and stir frying were more often used in the south. Concerning high-temperature cooking methods, their frequency of application varies between 15% in the EPIC cohort of North-Italy and 49% in the cohort of The Netherlands. Average consumption of fried, grilled and barbecued meat and fish ranges from a low of 12 g/day in the centres in southern Spain to a high of 91 g/day in northern Spain. High variation in both the kind of meat/fish consumed as well as its cooking methods is observed within EPIC. In order to use this variation for the evaluation of the impact of cooking methods on cancer risk, a questionnaire on meat and fish cooking methods is being developed and could be applied in the whole EPIC cohort.

Methodologic considerations in the design and analysis of nested case-control studies: association between cytokines and postoperative delirium.

PubMed

Ngo, Long H; Inouye, Sharon K; Jones, Richard N; Travison, Thomas G; Libermann, Towia A; Dillon, Simon T; Kuchel, George A; Vasunilashorn, Sarinnapha M; Alsop, David C; Marcantonio, Edward R

2017-06-06

The nested case-control study (NCC) design within a prospective cohort study is used when outcome data are available for all subjects, but the exposure of interest has not been collected, and is difficult or prohibitively expensive to obtain for all subjects. A NCC analysis with good matching procedures yields estimates that are as efficient and unbiased as estimates from the full cohort study. We present methodological considerations in a matched NCC design and analysis, which include the choice of match algorithms, analysis methods to evaluate the association of exposures of interest with outcomes, and consideration of overmatching. Matched, NCC design within a longitudinal observational prospective cohort study in the setting of two academic hospitals. Study participants are patients aged over 70 years who underwent scheduled major non-cardiac surgery. The primary outcome was postoperative delirium from in-hospital interviews and medical record review. The main exposure was IL-6 concentration (pg/ml) from blood sampled at three time points before delirium occurred. We used nonparametric signed ranked test to test for the median of the paired differences. We used conditional logistic regression to model the risk of IL-6 on delirium incidence. Simulation was used to generate a sample of cohort data on which unconditional multivariable logistic regression was used, and the results were compared to those of the conditional logistic regression. Partial R-square was used to assess the level of overmatching. We found that the optimal match algorithm yielded more matched pairs than the greedy algorithm. The choice of analytic strategy-whether to consider measured cytokine levels as the predictor or outcome-- yielded inferences that have different clinical interpretations but similar levels of statistical significance. Estimation results from NCC design using conditional logistic regression, and from simulated cohort design using unconditional logistic regression, were similar. We found minimal evidence for overmatching. Using a matched NCC approach introduces methodological challenges into the study design and data analysis. Nonetheless, with careful selection of the match algorithm, match factors, and analysis methods, this design is cost effective and, for our study, yields estimates that are similar to those from a prospective cohort study design.

Reproducibility and validity of a semi-quantitative FFQ for trace elements.

PubMed

Lee, Yujin; Park, Kyong

2016-09-01

The aim of this study was to test the reproducibility and validity of a self-administered FFQ for the Trace Element Study of Korean Adults in the Yeungnam area (SELEN). Study subjects were recruited from the SELEN cohort selected from rural and urban areas in Yeungnam, Korea. A semi-quantitative FFQ with 146 items was developed considering the dietary characteristics of cohorts in the study area. In a validation study, seventeen men and forty-eight women aged 38-62 years completed 3-d dietary records (DR) and two FFQ over a 3-month period. The validity was examined with the FFQ and DR, and the reproducibility was estimated using partial correlation coefficients, the Bland-Altman method and cross-classification. There were no significant differences between the mean intakes of selected nutrients as estimated from FFQ1, FFQ2 and DR. The median correlation coefficients for all nutrients were 0·47 and 0·56 in the reproducibility and validity tests, respectively. Bland-Altman's index and cross-classification showed acceptable agreement between FFQ1 and FFQ2 and between FFQ2 and DR. Ultimately, 78 % of the subjects were classified into the same and adjacent quartiles for most nutrients. In addition, the weighted κ value indicated that the two methods agreed fairly. In conclusion, this newly developed FFQ was a suitable dietary assessment method for the SELEN cohort study.

The clinical course of low back pain: a meta-analysis comparing outcomes in randomised clinical trials (RCTs) and observational studies

PubMed Central

2014-01-01

Background Evidence suggests that the course of low back pain (LBP) symptoms in randomised clinical trials (RCTs) follows a pattern of large improvement regardless of the type of treatment. A similar pattern was independently observed in observational studies. However, there is an assumption that the clinical course of symptoms is particularly influenced in RCTs by mere participation in the trials. To test this assumption, the aim of our study was to compare the course of LBP in RCTs and observational studies. Methods Source of studies CENTRAL database for RCTs and MEDLINE, CINAHL, EMBASE and hand search of systematic reviews for cohort studies. Studies include individuals aged 18 or over, and concern non-specific LBP. Trials had to concern primary care treatments. Data were extracted on pain intensity. Meta-regression analysis was used to compare the pooled within-group change in pain in RCTs with that in cohort studies calculated as the standardised mean change (SMC). Results 70 RCTs and 19 cohort studies were included, out of 1134 and 653 identified respectively. LBP symptoms followed a similar course in RCTs and cohort studies: a rapid improvement in the first 6 weeks followed by a smaller further improvement until 52 weeks. There was no statistically significant difference in pooled SMC between RCTs and cohort studies at any time point:- 6 weeks: RCTs: SMC 1.0 (95% CI 0.9 to 1.0) and cohorts 1.2 (0.7to 1.7); 13 weeks: RCTs 1.2 (1.1 to 1.3) and cohorts 1.0 (0.8 to 1.3); 27 weeks: RCTs 1.1 (1.0 to 1.2) and cohorts 1.2 (0.8 to 1.7); 52 weeks: RCTs 0.9 (0.8 to 1.0) and cohorts 1.1 (0.8 to 1.6). Conclusions The clinical course of LBP symptoms followed a pattern that was similar in RCTs and cohort observational studies. In addition to a shared ‘natural history’, enrolment of LBP patients in clinical studies is likely to provoke responses that reflect the nonspecific effects of seeking and receiving care, independent of the study design. PMID:24607083

Cohort Differences in the Availability of Informal Caregivers: Are the Boomers at Risk?

PubMed Central

Ryan, Lindsay H.; Smith, Jacqui; Antonucci, Toni C.; Jackson, James S.

2012-01-01

Purpose of the Study: We compare the close family resources of Baby Boomers (BBs) to previous cohorts of older adults at population level and then examine individual-level cohort comparisons of age-related trajectories of informal care availability from midlife into old age. Design and Methods: Population data from the U.S. Census and from the Health and Retirement Study (HRS) are used to identify a cohort similar to the BBs on marital status and fertility rates. Using generalized linear mixed models and 10-year longitudinal data from Depression and WWII parents (DWP; n = 1,052) and the parents of BBs (PBB; n = 3,573) in the HRS, we examine cohort differences in the time-varying likelihoods of being married and of having an adult child living within 10 miles. Results: The DWP had similar informal care resources at entry to old age as is expected in the BB. Longitudinal analyses of the DWP and PBB cohorts in HRS reveal that the availability of family changes over time and that the DWP cohort was significantly less likely to have a spouse or a grown child living nearby. Implications: These findings, and future projections based on them, have significant implications for institutions and public policy concerned with the informal caregiving needs of the Boomer cohort as they age. PMID:22298747

Stop Using the Modified Work APGAR to Measure Job Satisfaction

PubMed Central

Mielenz, Thelma J.; DeVellis, Robert F.; Battie, Michele C.; Carey, Timothy S.

2011-01-01

Background. The psychometric properties of the Modified Work APGAR (MWA) scale are not established, yet researchers use this scale as an overall measure of job satisfaction. Objective. Perform psychometric analyses on the MWA scale using data from two populations. Methods. A landmark occupational cohort and a clinical cohort are populations with low back pain studied. The first five items of the MWA scale measure social support from coworkers, one item measures dissatisfaction with job tasks, and the sixth item measures lack of social support from a supervisor. Exploratory principal components analyses were conducted in both cohorts. Results. In both cohorts, the first five items of the MWA scale loaded consistently onto one factor, social support from coworkers subscale. Conclusions. Unless researchers are interested in measuring social support from coworkers only, future studies should use other reliable and valid instruments to measure a broad range of psychosocial work characteristics. PMID:22191021

Bisphenol A levels in human urine.

PubMed Central

Matsumoto, Akiko; Kunugita, Naoki; Kitagawa, Kyoko; Isse, Toyohi; Oyama, Tsunehiro; Foureman, Gary L; Morita, Masatoshi; Kawamoto, Toshihiro

2003-01-01

The estrogenic effects of bisphenol A (BPA) have been reported in human cells (E-screen assays) and in (italic)in vivo(/italic) studies of rodents, although the latter reports remain controversial, as do the exposure levels and adverse health effects of BPA in humans. In this study we report on an analytical high-performance liquid chromatography/fluorescence method for BPA and its conjugate in human urine and on the application of this method in two student cohorts. Urine, along with information on smoking, alcohol intake, and coffee/tea consumption, was collected in two different years from two different groups of university students, 50 in 1992 and 56 in 1999. Overall, the urinary BPA levels in the students in 1992 were significantly higher than were those in 1999. The BPA levels were also positively correlated with coffee and tea consumption in the 1992 cohort but not in the 1999 cohort. We speculate that recent changes made in Japan regarding the interior coating of cans used to package these beverages may partly explain these findings. PMID:12515686

The Cancer Epidemiology Descriptive Cohort Database: A Tool to Support Population-Based Interdisciplinary Research

PubMed Central

Kennedy, Amy E.; Khoury, Muin J.; Ioannidis, John P.A.; Brotzman, Michelle; Miller, Amy; Lane, Crystal; Lai, Gabriel Y.; Rogers, Scott D.; Harvey, Chinonye; Elena, Joanne W.; Seminara, Daniela

2017-01-01

Background We report on the establishment of a web-based Cancer Epidemiology Descriptive Cohort Database (CEDCD). The CEDCD’s goals are to enhance awareness of resources, facilitate interdisciplinary research collaborations, and support existing cohorts for the study of cancer-related outcomes. Methods Comprehensive descriptive data were collected from large cohorts established to study cancer as primary outcome using a newly developed questionnaire. These included an inventory of baseline and follow-up data, biospecimens, genomics, policies, and protocols. Additional descriptive data extracted from publicly available sources were also collected. This information was entered in a searchable and publicly accessible database. We summarized the descriptive data across cohorts and reported the characteristics of this resource. Results As of December 2015, the CEDCD includes data from 46 cohorts representing more than 6.5 million individuals (29% ethnic/racial minorities). Overall, 78% of the cohorts have collected blood at least once, 57% at multiple time points, and 46% collected tissue samples. Genotyping has been performed by 67% of the cohorts, while 46% have performed whole-genome or exome sequencing in subsets of enrolled individuals. Information on medical conditions other than cancer has been collected in more than 50% of the cohorts. More than 600,000 incident cancer cases and more than 40,000 prevalent cases are reported, with 24 cancer sites represented. Conclusions The CEDCD assembles detailed descriptive information on a large number of cancer cohorts in a searchable database. Impact Information from the CEDCD may assist the interdisciplinary research community by facilitating identification of well-established population resources and large-scale collaborative and integrative research. PMID:27439404

The Inconvenience of Convenience Cohorts: Rhabdomyosarcoma and the PAX-FOXO1 Biomarker

PubMed Central

Rosenberg, Abby R.; Skapek, Stephen X.; Hawkins, Douglas S.

2012-01-01

“Convenience cohorts” comprise individuals thought to represent the general population, but chosen because they are readily available for evaluation, rather than at random. As such, these methods are subject to bias and may be misleading. Convenience cohorts have been used to investigate the prognostic significance of chromosomal translocations between the PAX3 or PAX7 and the FOXO1 genes in rhabdomyosarcoma, the most common pediatric sarcoma. However, retrospective studies assessing the role of PAX-FOXO1 translocations have yielded inconsistent results. This review highlights the findings from several clinical correlation studies of the PAX-FOXO1 biomarker and illustrates the challenges of using such methods to draw clinical conclusions. PMID:22564868

Costs and Efficiency of Online and Offline Recruitment Methods: A Web-Based Cohort Study.

PubMed

Christensen, Tina; Riis, Anders H; Hatch, Elizabeth E; Wise, Lauren A; Nielsen, Marie G; Rothman, Kenneth J; Toft Sørensen, Henrik; Mikkelsen, Ellen M

2017-03-01

The Internet is widely used to conduct research studies on health issues. Many different methods are used to recruit participants for such studies, but little is known about how various recruitment methods compare in terms of efficiency and costs. The aim of our study was to compare online and offline recruitment methods for Internet-based studies in terms of efficiency (number of recruited participants) and costs per participant. We employed several online and offline recruitment methods to enroll 18- to 45-year-old women in an Internet-based Danish prospective cohort study on fertility. Offline methods included press releases, posters, and flyers. Online methods comprised advertisements placed on five different websites, including Facebook and Netdoktor.dk. We defined seven categories of mutually exclusive recruitment methods and used electronic tracking via unique Uniform Resource Locator (URL) and self-reported data to identify the recruitment method for each participant. For each method, we calculated the average cost per participant and efficiency, that is, the total number of recruited participants. We recruited 8252 study participants. Of these, 534 were excluded as they could not be assigned to a specific recruitment method. The final study population included 7724 participants, of whom 803 (10.4%) were recruited by offline methods, 3985 (51.6%) by online methods, 2382 (30.8%) by online methods not initiated by us, and 554 (7.2%) by other methods. Overall, the average cost per participant was €6.22 for online methods initiated by us versus €9.06 for offline methods. Costs per participant ranged from €2.74 to €105.53 for online methods and from €0 to €67.50 for offline methods. Lowest average costs per participant were for those recruited from Netdoktor.dk (€2.99) and from Facebook (€3.44). In our Internet-based cohort study, online recruitment methods were superior to offline methods in terms of efficiency (total number of participants enrolled). The average cost per recruited participant was also lower for online than for offline methods, although costs varied greatly among both online and offline recruitment methods. We observed a decrease in the efficiency of some online recruitment methods over time, suggesting that it may be optimal to adopt multiple online methods. ©Tina Christensen, Anders H Riis, Elizabeth E Hatch, Lauren A Wise, Marie G Nielsen, Kenneth J Rothman, Henrik Toft Sørensen, Ellen M Mikkelsen. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 01.03.2017.

South Yorkshire Cohort: a 'cohort trials facility' study of health and weight - protocol for the recruitment phase.

PubMed

Relton, Clare; Bissell, Paul; Smith, Christine; Blackburn, Joanna; Cooper, Cindy L; Nicholl, Jon; Tod, Angela; Copeland, Rob; Loban, Amanda; Chater, Tim; Thomas, Kate; Young, Tracy; Weir, Carol; Harrison, Gill; Millbourn, Alison; Manners, Rachel

2011-08-11

Growing levels of both obesity and chronic disease in the general population pose a major public health problem. In the UK, an innovative 'health and weight' cohort trials facility, the 'South Yorkshire Cohort', is being built in order to provide robust evidence to inform policy, commissioning and clinical decisions in this field. This protocol reports the design of the facility and outlines the recruitment phase methods. The South Yorkshire Cohort health and weight study uses the cohort multiple randomised controlled trial design. This design recruits a large observational cohort of patients with the condition(s) of interest which then provides a facility for multiple randomised controlled trials (with large representative samples of participants, long term outcomes as standard, increased comparability between each trial conducted within the cohort and increased efficiency particularly for trials of expensive interventions) as well as ongoing information as to the natural history of the condition and treatment as usual.This study aims to recruit 20,000 participants to the population based South Yorkshire Cohort health and weight research trials facility. Participants are recruited by invitation letters from their General Practitioners. Data is collected using postal and/or online patient self completed Health Questionnaires. NHS numbers will be used to facilitate record linkage and access to routine data. Participants are eligible if they are: aged 16 - 85 years, registered with one of 40 practices in South Yorkshire, provide consent for further contact from the researchers and to have their information used to look at the benefit of health treatments. The first wave of data is being collected during 2010/12 and further waves are planned at 2 - 5 year intervals for the planned 20 year duration of the facility. The South Yorkshire Cohort combines the strengths of the standard observational, longitudinal cohort study design with a population based cohort facility for multiple randomised controlled trials in a range of long term health and weight related conditions (including obesity). This infrastructure will allow the rapid and cheap identification and recruitment of patients, and facilitate the provision of robust evidence to inform the management and self-management of health and weight.

Following the footprints of polymorphic inversions on SNP data: from detection to association tests

PubMed Central

Cáceres, Alejandro; González, Juan R.

2015-01-01

Inversion polymorphisms have important phenotypic and evolutionary consequences in humans. Two different methodologies have been used to infer inversions from SNP dense data, enabling the use of large cohorts for their study. One approach relies on the differences in linkage disequilibrium across breakpoints; the other one captures the internal haplotype groups that tag the inversion status of chromosomes. In this article, we assessed the convergence of the two methods in the detection of 20 human inversions that have been reported in the literature. The methods converged in four inversions including inv-8p23, for which we studied its association with low-BMI in American children. Using a novel haplotype tagging method with control on inversion ancestry, we computed the frequency of inv-8p23 in two American cohorts and observed inversion haplotype admixture. Accounting for haplotype ancestry, we found that the European inverted allele in children carries a recessive risk of underweight, validated in an independent Spanish cohort (combined: OR= 2.00, P = 0.001). While the footprints of inversions on SNP data are complex, we show that systematic analyses, such as convergence of different methods and controlling for ancestry, can reveal the contribution of inversions to the ancestral composition of populations and to the heritability of human disease. PMID:25672393

Impact of Concomitant Chemotherapy on Outcomes of Radiation Therapy for Head-and-Neck Cancer: A Population-Based Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Shlok; Kong, Weidong; Booth, Christopher M.

2014-01-01

Purpose: Clinical trials have shown that the addition of chemotherapy to radiation therapy (RT) improves survival in advanced head-and-neck cancer. The objective of this study was to describe the effectiveness of concomitant chemoradiation therapy (C-CRT) in routine practice. Methods and Materials: This was a population-based cohort study. Electronic records of treatment from all provincial cancer centers were linked to a population--based cancer registry to describe the adoption of C-CRT for head-and-neck cancer patients in Ontario, Canada. The study population was then divided into pre- and postadoption cohorts, and their outcomes were compared. Results: Between 1992 and 2008, 18,867 patients hadmore » diagnoses of head-and-neck cancer in Ontario, of whom 7866 (41.7%) were treated with primary RT. The proportion of primary RT cases that received C-CRT increased from 2.2% in the preadoption cohort (1992-1998) to 39.3% in the postadoption cohort (2003-2008). Five-year survival among all primary RT cases increased from 43.6% in the preadoption cohort to 51.8% in the postadoption cohort (P<.001). Over the same period, treatment-related hospital admissions increased significantly, but there was no significant increase in treatment-related deaths. Conclusions: C-CRT was widely adopted in Ontario after 2003, and its adoption was temporally associated with an improvement in survival.« less

Assessing family planning service-delivery skills in Kenya.

PubMed

Valadez, J J; Transgrud, R; Mbugua, M; Smith, T

1997-06-01

This report demonstrates the use of Lot Quality Assurance Sampling (LQAS) to evaluate the technical competence of two cohorts of family planning service providers in Kenya trained with a new curriculum. One cohort had just finished training within two months of the study. The other cohort was the first group trained with the new curriculum about one year before the study. LQAS was adapted from industrial and other public health applications to assess both the individual competence of 30 service providers and the competence of each cohort. Results show that Cohorts One and Two did not differ markedly in the number of tasks needing improvement. However, both cohorts exhibited more tasks needing improvement in counseling skills as compared with physical examination skills or with all other skills. Care-givers who were not currently providing services accounted for most service-delivery problems. This result suggests that providers' use of their skills explains their ability to retain service-delivery skills learned in training to a greater degree than does the amount of time elapsed since they were trained. LQAS proved to be a rapid, easy-to-use empirical method for management decisionmaking for improvement of a family planning training curriculum and services.

Assessing adult mortality in HIV-1-afflicted Zimbabwe (1998 -2003).

PubMed Central

Lopman, Ben A.; Barnabas, Ruanne; Hallett, Timothy B.; Nyamukapa, Constance; Mundandi, Costa; Mushati, Phyllis; Garnett, Geoff P.; Gregson, Simon

2006-01-01

OBJECTIVE: To compare alternative methods to vital registration systems for estimating adult mortality, and describe patterns of mortality in Manicaland, Zimbabwe, which has been severely affected by HIV. METHODS: We compared estimates of adult mortality from (1) a single question on household mortality, (2) repeated household censuses, and (3) an adult cohort study with linked HIV testing from Manicaland, with a mathematical model fitted to local age-specific HIV prevalence (1998 -2000). FINDINGS: The crude death rate from the single question (29 per 1000 person-years) was roughly consistent with that from the mathematical model (22 -25 per 1000 person-years), but much higher than that from the household censuses (12 per 1000 person-years). Adult mortality in the household censuses (males 0.65; females 0.51) was lower than in the cohort study (males 0.77; females 0.57), while mathematical models gave a much higher estimate, especially for females (males 0.80 -0.83; females 0.75 -0.80). The population attributable fraction of adult deaths due to HIV was 0.61 for men and 0.70 for women, with life expectancy estimated to be 34.3 years for males and 38.2 years for females. CONCLUSION: Each method for estimating adult mortality had limitations in terms of loss to follow-up (cohort study), under-ascertainment (household censuses), transparency of underlying processes (single question), and sensitivity to parameterization (mathematical model). However, these analyses make clear the advantages of longitudinal cohort data, which provide more complete ascertainment than household censuses, highlight possible inaccuracies in model assumptions, and allow direct quantification of the impact of HIV. PMID:16583077

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mast, Mirjam E., E-mail: m.mast@mchaaglanden.nl; Heijenbrok, Mark W.; Petoukhova, Anna L.

Purpose: Breast cancer radiotherapy has been associated with an increased risk of cardiac toxicity. However, no data are available on the probability of developing coronary artery disease (CAD) in breast cancer patients when compared with healthy women. Therefore, baseline coronary artery calcium (CAC) scores, as an accepted tool to predict CAD, were determined and compared with the CAC scores of a healthy, asymptomatic cohort, the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. Methods and Materials: Eighty consecutive patients with ductal carcinoma in situ or infiltrative breast cancer referred for radiotherapy after breast-conserving surgery were included in our study. Their cardiovascular riskmore » profile was registered, and a 64 multislice CT scan was performed. The CAC scores of an unselected (Caucasian only) Radiotherapy Centre West (RCWEST) cohort, as well as of those of a selected (comorbidity and race adjusted) RCWEST cohort, were determined. The scores of both cohorts were compared with those of the female (Caucasian only) MESA cohort. Results: For the unselected RCWEST cohort (n = 62) we found significant (p < .01) higher scores for women in the 55-64 age category compared with those of the MESA cohort. In the selected cohort (n = 55) the CAC scores of the women in the age category 55-64 were significantly (p = .02) higher compared with the MESA cohort. No significant differences were noted in the other age categories. Conclusion: Both cohorts revealed that CAC scores in the 55-64 age category were significantly higher than the CAC scores in the asymptomatic (female) MESA population. These data suggest that breast cancer patients bear a higher risk of developing coronary heart disease before the start of radiotherapy. Therefore, measures to decrease cardiac dose further in breast cancer radiotherapy are even more important.« less

Portfolio Development as a Three-Semester Process: The Value of Sequential Experience.

ERIC Educational Resources Information Center

Senne, Terry A.

This study examined nine cohort teacher candidates from each of two physical education teacher education (PETE) programs developed teaching portfolios in three consecutive semesters of comparable courses: (1) elementary methods; (2) secondary methods; and (3) the student teaching internship. Studied were changes over time in teacher candidate…

Specialist Cohort Event Monitoring studies: a new study method for risk management in pharmacovigilance.

PubMed

Layton, Deborah; Shakir, Saad A W

2015-02-01

The evolving regulatory landscape has heightened the need for innovative, proactive, efficient and more meaningful solutions for 'real-world' post-authorization safety studies (PASS) that not only align with risk management objectives to gather additional safety monitoring information or assess a pattern of drug utilization, but also satisfy key regulatory requirements for marketing authorization holder risk management planning and execution needs. There is a need for data capture across the primary care and secondary care interface, or for exploring use of new medicines in secondary care to support conducting PASS. To fulfil this need, event monitoring has evolved. The Specialist Cohort Event Monitoring (SCEM) study is a new application that enables a cohort of patients prescribed a medicine in the hospital and secondary care settings to be monitored. The method also permits the inclusion of a comparator cohort of patients receiving standard care, or another counterfactual comparator group, to be monitored concurrently, depending on the study question. The approach has been developed in parallel with the new legislative requirement for pharmaceutical companies to undertake a risk management plan as part of post-authorization safety monitoring. SCEM studies recognize that the study population comprises those patients who may have treatment initiated under the care of specialist health care professionals and who are more complex in terms of underlying disease, co-morbidities and concomitant medications than the general disease population treated in primary care. The aims of this paper are to discuss the SCEM new-user study design, rationale and features that aim to address possible bias (such as selection bias) and current applications.

Observational Studies: Cohort and Case-Control Studies

PubMed Central

Song, Jae W.; Chung, Kevin C.

2010-01-01

Observational studies are an important category of study designs. To address some investigative questions in plastic surgery, randomized controlled trials are not always indicated or ethical to conduct. Instead, observational studies may be the next best method to address these types of questions. Well-designed observational studies have been shown to provide results similar to randomized controlled trials, challenging the belief that observational studies are second-rate. Cohort studies and case-control studies are two primary types of observational studies that aid in evaluating associations between diseases and exposures. In this review article, we describe these study designs, methodological issues, and provide examples from the plastic surgery literature. PMID:20697313

Trends in oral cavity, pharyngeal, oesophageal and gastric cancer mortality rates in Spain, 1952–2006: an age-period-cohort analysis

PubMed Central

2014-01-01

Background Although oral cavity, pharyngeal, oesophageal and gastric cancers share some risk factors, no comparative analysis of mortality rate trends in these illnesses has been undertaken in Spain. This study aimed to evaluate the independent effects of age, death period and birth cohort on the mortality rates of these tumours. Methods Specific and age-adjusted mortality rates by tumour and sex were analysed. Age-period-cohort log-linear models were fitted separately for each tumour and sex, and segmented regression models were used to detect changes in period- and cohort-effect curvatures. Results Among men, the period-effect curvatures for oral cavity/pharyngeal and oesophageal cancers displayed a mortality trend that rose until 1995 and then declined. Among women, oral cavity/pharyngeal cancer mortality increased throughout the study period whereas oesophageal cancer mortality decreased after 1970. Stomach cancer mortality decreased in both sexes from 1965 onwards. Lastly, the cohort-effect curvature showed a certain degree of similarity for all three tumours in both sexes, which was greater among oral cavity, pharyngeal and oesophageal cancers, with a change point in evidence, after which risk of death increased in cohorts born from the 1910-1920s onwards and decreased among the 1950–1960 cohorts and successive generations. This latter feature was likewise observed for stomach cancer. Conclusions While the similarities of the cohort effects in oral cavity/pharyngeal, oesophageal and gastric tumours support the implication of shared risk factors, the more marked changes in cohort-effect curvature for oral cavity/pharyngeal and oesophageal cancer could be due to the greater influence of some risk factors in their aetiology, such as smoking and alcohol consumption. The increase in oral cavity/pharyngeal cancer mortality in women deserves further study. PMID:24725381

Effect of Alcoholic Intoxication on the Risk of Inflammatory Bowel Disease: A Nationwide Retrospective Cohort Study

PubMed Central

Hsu, Tai-Yi; Shih, Hong-Mo; Wang, Yu-Chiao; Lin, Leng-Chieh; He, Guan-Yi; Chen, Chih-Yu; Kao, Chia-Hung; Chen, Chao-Hsien

2016-01-01

Purpose This study investigated whether alcoholic intoxication (AI) increases the risk of inflammatory bowel disease (IBD) by using a population-based database in Taiwan. Methods This retrospective matched-cohort study included 57 611 inpatients with new-onset AI (AI cohort) and 230 444 randomly selected controls (non-AI cohort). Each patient was monitored for 10 years to individually identify those who were subsequently diagnosed with Crohn disease (CD) and ulcerative colitis (UC) during the follow-up period. Cox proportional hazard regression analysis was conducted to determine the risk of IBD in patients with AI compared with controls without AI. Results The incidence rate of IBD during the 10-year follow-up period was 2.69 per 1 000 person-years and 0.49 per 1 000 person-years in the AI and non-AI cohorts, respectively. After adjustment for age, sex, and comorbidity, the AI cohort exhibited a 3.17-fold increased risk of IBD compared with the non-AI cohort (hazard ratio [HR] = 3.17, 95% confidence interval [CI] = 2.19–4.58). Compared with the non-AI cohort, the HRs of CD and UC were 4.40 and 2.33 for the AI cohort, respectively. After stratification for the severity of AI according to the duration of hospital stay, the adjusted HRs exhibited a significant correlation with the severity; the HRs of IBD were 1.76, 6.83, and 19.9 for patients with mild, moderate, and severe AI, respectively (p for the trend < .0001). Conclusion The risk of IBD was higher in patients with AI and increased with the length of hospital stay. PMID:27802288

Alcoholic Beverage Preference and Dietary Habits in Elderly across Europe: Analyses within the Consortium on Health and Ageing: Network of Cohorts in Europe and the United States (CHANCES) Project

PubMed Central

Sluik, Diewertje; Jankovic, Nicole; O’Doherty, Mark G.; Geelen, Anouk; Schöttker, Ben; Rolandsson, Olov; Kiefte-de Jong, Jessica C.; Ferrieres, Jean; Bamia, Christina; Fransen, Heidi P.; Boer, Jolanda M. A.; Eriksson, Sture; Martínez, Begoña; Huerta, José María; Kromhout, Daan; de Groot, Lisette C. P. G. M.; Franco, Oscar H.; Trichopoulou, Antonia; Boffetta, Paolo; Kee, Frank; Feskens, Edith J. M.

2016-01-01

Introduction The differential associations of beer, wine, and spirit consumption on cardiovascular risk found in observational studies may be confounded by diet. We described and compared dietary intake and diet quality according to alcoholic beverage preference in European elderly. Methods From the Consortium on Health and Ageing: Network of Cohorts in Europe and the United States (CHANCES), seven European cohorts were included, i.e. four sub-cohorts from EPIC-Elderly, the SENECA Study, the Zutphen Elderly Study, and the Rotterdam Study. Harmonized data of 29,423 elderly participants from 14 European countries were analyzed. Baseline data on consumption of beer, wine, and spirits, and dietary intake were collected with questionnaires. Diet quality was assessed using the Healthy Diet Indicator (HDI). Intakes and scores across categories of alcoholic beverage preference (beer, wine, spirit, no preference, non-consumers) were adjusted for age, sex, socio-economic status, self-reported prevalent diseases, and lifestyle factors. Cohort-specific mean intakes and scores were calculated as well as weighted means combining all cohorts. Results In 5 of 7 cohorts, persons with a wine preference formed the largest group. After multivariate adjustment, persons with a wine preference tended to have a higher HDI score and intake of healthy foods in most cohorts, but differences were small. The weighted estimates of all cohorts combined revealed that non-consumers had the highest fruit and vegetable intake, followed by wine consumers. Non-consumers and persons with no specific preference had a higher HDI score, spirit consumers the lowest. However, overall diet quality as measured by HDI did not differ greatly across alcoholic beverage preference categories. Discussion This study using harmonized data from ~30,000 elderly from 14 European countries showed that, after multivariate adjustment, dietary habits and diet quality did not differ greatly according to alcoholic beverage preference. PMID:27548323

Interactive Cohort Identification of Sleep Disorder Patients Using Natural Language Processing and i2b2

PubMed Central

Chen, W.; Kowatch, R.; Lin, S.; Splaingard, M.

2015-01-01

Summary Nationwide Children’s Hospital established an i2b2 (Informatics for Integrating Biology & the Bedside) application for sleep disorder cohort identification. Discrete data were gleaned from semistructured sleep study reports. The system showed to work more efficiently than the traditional manual chart review method, and it also enabled searching capabilities that were previously not possible. Objective We report on the development and implementation of the sleep disorder i2b2 cohort identification system using natural language processing of semi-structured documents. Methods We developed a natural language processing approach to automatically parse concepts and their values from semi-structured sleep study documents. Two parsers were developed: a regular expression parser for extracting numeric concepts and a NLP based tree parser for extracting textual concepts. Concepts were further organized into i2b2 ontologies based on document structures and in-domain knowledge. Results 26,550 concepts were extracted with 99% being textual concepts. 1.01 million facts were extracted from sleep study documents such as demographic information, sleep study lab results, medications, procedures, diagnoses, among others. The average accuracy of terminology parsing was over 83% when comparing against those by experts. The system is capable of capturing both standard and non-standard terminologies. The time for cohort identification has been reduced significantly from a few weeks to a few seconds. Conclusion Natural language processing was shown to be powerful for quickly converting large amount of semi-structured or unstructured clinical data into discrete concepts, which in combination of intuitive domain specific ontologies, allows fast and effective interactive cohort identification through the i2b2 platform for research and clinical use. PMID:26171080

Changes in cohort wealth over a generation.

PubMed

David, M H; Menchik, P L

1988-08-01

Empirical computation of expected wealth is hampered by two problems: mortality risks vary in the population and over time; and observation of net estates for most cohorts is truncated, as some individuals in a cohort survive the calendar date on which observation is terminated. These two problems are solved in estimating cohort wealth for a sample of Wisconsin taxpayers. Hazard rate models of differential occupational mortality risks were estimated from the occupational information on the tax records. Values of net estate are simulated for individuals in each birth cohort who survived. Survivors have characteristics that imply greater wealth holdings than the deceased in every birth year covered by the study (1890-1924). Because of this, estimates of wealth-age relationships produced by the estate multiplier method for any given year will have a serious downward bias. Longitudinal data imply that dissaving does not occur after age 65.

Association of β-defensin copy number and psoriasis in three cohorts of European origin

PubMed Central

Stuart, Philip E; Hüffmeier, Ulrike; Nair, Rajan P; Palla, Raquel; Tejasvi, Trilokraj; Schalkwijk, Joost; Elder, James T; Reis, Andre; Armour, John AL

2012-01-01

A single previous study has demonstrated significant association of psoriasis with copy number of beta-defensin genes, using DNA from psoriasis cases and controls from Nijmegen and Erlangen. In this study we attempted to replicate that finding in larger new cohorts from Erlangen (N = 2017) and Michigan (N = 5412), using improved methods for beta-defensin copy number determination based on the paralog ratio test (PRT), and enhanced methods of analysis and association testing implemented in the CNVtools resource. We demonstrate that the association with psoriasis found in the discovery sample is maintained after applying improved typing and analysis methods (p = 5.5 × 10−4, OR = 1.25). We also find that the association is replicated in 2616 cases and 2526 controls from Michigan, although at reduced significance (p = 0.014), but not in new samples from Erlangen (1396 cases and 621 controls, p = 0.38). Meta-analysis across all cohorts suggests a nominally significant association (p = 6.6 × 10−3/2 × 10−4) with an effect size (OR = 1.081) much lower than found in the discovery study (OR = 1.32). This reduced effect size and significance on replication is consistent with a genuine but weak association. PMID:22739795

Identification of Child Maltreatment Using Prospective and Self-Report Methodologies: A Comparison of Maltreatment Incidence and Relation to Later Psychopathology

ERIC Educational Resources Information Center

Shaffer, Anne; Huston, Lisa; Egeland, Byron

2008-01-01

Objectives: One of the greatest methodological problems in the study of childhood maltreatment is the discrepancy in methods by which cases of child maltreatment are identified. The current study compared incidents of maltreatment identified prospectively, retrospectively, or through a combination of both methods. Method: Within a cohort of 170…

A review of job-exposure matrix methodology for application to workers exposed to radiation from internally deposited plutonium or other radioactive materials.

PubMed

Liu, Hanhua; Wakeford, Richard; Riddell, Anthony; O'Hagan, Jacqueline; MacGregor, David; Agius, Raymond; Wilson, Christine; Peace, Mark; de Vocht, Frank

2016-03-01

Any potential health effects of radiation emitted from radionuclides deposited in the bodies of workers exposed to radioactive materials can be directly investigated through epidemiological studies. However, estimates of radionuclide exposure and consequent tissue-specific doses, particularly for early workers for whom monitoring was relatively crude but exposures tended to be highest, can be uncertain, limiting the accuracy of risk estimates. We review the use of job-exposure matrices (JEMs) in peer-reviewed epidemiological and exposure assessment studies of nuclear industry workers exposed to radioactive materials as a method for addressing gaps in exposure data, and discuss methodology and comparability between studies. We identified nine studies of nuclear worker cohorts in France, Russia, the USA and the UK that had incorporated JEMs in their exposure assessments. All these JEMs were study or cohort-specific, and although broadly comparable methodologies were used in their construction, this is insufficient to enable the transfer of any one JEM to another study. Moreover there was often inadequate detail on whether, or how, JEMs were validated. JEMs have become more detailed and more quantitative, and this trend may eventually enable better comparison across, and the pooling of, studies. We conclude that JEMs have been shown to be a valuable exposure assessment methodology for imputation of missing exposure data for nuclear worker cohorts with data not missing at random. The next step forward for direct comparison or pooled analysis of complete cohorts would be the use of transparent and transferable methods.

Composite Partial Likelihood Estimation Under Length-Biased Sampling, With Application to a Prevalent Cohort Study of Dementia

PubMed Central

Huang, Chiung-Yu; Qin, Jing

2013-01-01

The Canadian Study of Health and Aging (CSHA) employed a prevalent cohort design to study survival after onset of dementia, where patients with dementia were sampled and the onset time of dementia was determined retrospectively. The prevalent cohort sampling scheme favors individuals who survive longer. Thus, the observed survival times are subject to length bias. In recent years, there has been a rising interest in developing estimation procedures for prevalent cohort survival data that not only account for length bias but also actually exploit the incidence distribution of the disease to improve efficiency. This article considers semiparametric estimation of the Cox model for the time from dementia onset to death under a stationarity assumption with respect to the disease incidence. Under the stationarity condition, the semiparametric maximum likelihood estimation is expected to be fully efficient yet difficult to perform for statistical practitioners, as the likelihood depends on the baseline hazard function in a complicated way. Moreover, the asymptotic properties of the semiparametric maximum likelihood estimator are not well-studied. Motivated by the composite likelihood method (Besag 1974), we develop a composite partial likelihood method that retains the simplicity of the popular partial likelihood estimator and can be easily performed using standard statistical software. When applied to the CSHA data, the proposed method estimates a significant difference in survival between the vascular dementia group and the possible Alzheimer’s disease group, while the partial likelihood method for left-truncated and right-censored data yields a greater standard error and a 95% confidence interval covering 0, thus highlighting the practical value of employing a more efficient methodology. To check the assumption of stable disease for the CSHA data, we also present new graphical and numerical tests in the article. The R code used to obtain the maximum composite partial likelihood estimator for the CSHA data is available in the online Supplementary Material, posted on the journal web site. PMID:24000265

Multicenter cohort study on association of genotypes with prospective sports concussion: methods, lessons learned, and recommendations.

PubMed

Terrell, Thomas R; Bostick, Roberd; Barth, Jeffrey; Sloane, Richard; Cantu, Robert C; Bennett, Ellen; Galloway, Leslie; Laskowitz, Daniel; Erlanger, Dave; McKeag, Doug; Valentine, Verle; Nichols, Gregory

2017-01-01

Approximately 3.8 million sports related TBIs occur per year. Genetic variation may affect both TBI risk and post-TBI clinical outcome. Limited research has focused on genetic risk for concussion among athletes. We describe the design, methods, and baseline characteristics of this prospective cohort study designed to investigate a potential association between genetic polymorphisms of apolipoprotein E gene, APOE promoter G-219T, and Tau gene exon 6 polymorphisms (Ser53 Pro and Hist47Tyr) with: 1) the risk of prospective concussion; 2) concussion severity; and 3) postconcussion neurocognitive recovery. The prospective cohort study included a final population of 2947 college, high school, and professional athletes. Baseline data collection included a concussion/medical history questionnaire, neuropsychological (NP) testing, and genetic sampling for the genetic polymorphisms. Data collection on new concussions experienced utilized post-concussion history/mental status form, Lovell post-concussion symptom score, Standardized Assessment of Concussion (SAC) and/or the Sports Concussion Assessment Tool (SCAT)-1/SCAT-2, and post-concussion NP testing. This paper is focused on discussing the important methodological considerations, organizational challenges and lessons learned in the completion of a multi-center prospective cohort study. A total of 3740 subjects enrolled, with a total of 335 concussions experienced. Of critical importance to the success of a study of this type is to successfully recruit committed institutions with qualified local study personnel, obtain "buy-in" from study sites, and cultivate strong working relationships with study sites. The use of approved incentives may improve study site recruitment, enhance retention, and enhance compliance with study protocols. Future publications will detail the specific findings of this study. Collaborative research is very likely needed given the nature of this study population.

Exclusion and Inclusion of Nonwhite Ethnic Minority Groups in 72 North American and European Cardiovascular Cohort Studies

PubMed Central

Ranganathan, Meghna; Bhopal, Raj

2006-01-01

Background Cohort studies are recommended for understanding ethnic disparities in cardiovascular disease. Our objective was to review the process for identifying, including, and excluding ethnic minority populations in published cardiovascular cohort studies in Europe and North America. Methods and Findings We found the literature using Medline (1966–2005), Embase (1980–2001), Cinahl, Web of Science, and citations from references; consultations with colleagues; Internet searches; and RB's personal files. A total of 72 studies were included, 39 starting after 1975. Decision-making on inclusion and exclusion of racial/ethnic groups, the conceptual basis of race/ethnicity, and methods of classification of racial/ethnic groups were rarely explicit. Few publications provided details on the racial/ethnic composition of the study setting or sample, and 39 gave no description. Several studies were located in small towns or in occupational settings, where ethnic minority populations are underrepresented. Studies on general populations usually had too few participants for analysis by race/ethnicity. Eight studies were explicitly on Caucasians/whites, and two excluded ethnic minority groups from the whole or part of the study on the basis of language or birthplace criteria. Ten studies were designed to compare white and nonwhite populations, while five studies focused on one nonwhite racial/ethnic group; all 15 of these were performed in the US. Conclusions There is a shortage of information from cardiovascular cohort studies on racial/ethnic minority populations, although this has recently changed in the US. There is, particularly in Europe, an inequity resulting from a lack of research data in nonwhite populations. Urgent action is now required in Europe to address this disparity. PMID:16379500

Using probabilistic record linkage methods to identify Australian Indigenous women on the Queensland Pap Smear Register: the National Indigenous Cervical Screening Project.

PubMed

Whop, Lisa J; Diaz, Abbey; Baade, Peter; Garvey, Gail; Cunningham, Joan; Brotherton, Julia M L; Canfell, Karen; Valery, Patricia C; O'Connell, Dianne L; Taylor, Catherine; Moore, Suzanne P; Condon, John R

2016-02-12

To evaluate the feasibility and reliability of record linkage of existing population-based data sets to determine Indigenous status among women receiving Pap smears. This method may allow for the first ever population measure of Australian Indigenous women's cervical screening participation rates. A linked data set of women aged 20-69 in the Queensland Pap Smear Register (PSR; 1999-2011) and Queensland Cancer Registry (QCR; 1997-2010) formed the Initial Study Cohort. Two extracts (1995-2011) were taken from Queensland public hospitals data (Queensland Hospital Admitted Patient Data Collection, QHAPDC) for women, aged 20-69, who had ever been identified as Indigenous (extract 1) and had a diagnosis or procedure code relating to cervical cancer (extract 2). The Initial Study Cohort was linked to extract 1, and women with cervical cancer in the initial cohort were linked to extract 2. The proportion of women in the Initial Cohort who linked with the extracts (true -pairs) is reported, as well as the proportion of potential pairs that required clerical review. After assigning Indigenous status from QHAPDC to the PSR, the proportion of women identified as Indigenous was calculated using 4 algorithms, and compared. There were 28,872 women (2.1%) from the Initial Study Cohort who matched to an ever Indigenous record in extract 1 (n=76,831). Women with cervical cancer in the Initial Study Cohort linked to 1385 (71%) records in extract 2. The proportion of Indigenous women ranged from 2.00% to 2.08% when using different algorithms to define Indigenous status. The Final Study Cohort included 1,372,823 women (PSR n=1,374,401; QCR n=1955), and 5,062,118 records. Indigenous status in Queensland cervical screening data was successfully ascertained through record linkage, allowing for the crucial assessment of the current cervical screening programme for Indigenous women. Our study highlights the need to include Indigenous status on Pap smear request and report forms in any renewed and redesigned cervical screening programme in Australia. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A Methodology to Detect Abnormal Relative Wall Shear Stress on the Full Surface of the Thoracic Aorta Using 4D Flow MRI

PubMed Central

van Ooij, Pim; Potters, Wouter V.; Nederveen, Aart J.; Allen, Bradley D.; Collins, Jeremy; Carr, James; Malaisrie, S. Chris; Markl, Michael; Barker, Alex J.

2014-01-01

Purpose To compute cohort-averaged wall shear stress (WSS) maps in the thoracic aorta of patients with aortic dilatation or valvular stenosis and to detect abnormal regional WSS. Methods Systolic WSS vectors, estimated from 4D flow MRI data, were calculated along the thoracic aorta lumen in 10 controls, 10 patients with dilated aortas and 10 patients with aortic valve stenosis. 3D segmentations of each aorta were co-registered by group and used to create a cohort-specific aortic geometry. The WSS vectors of each subject were interpolated onto the corresponding cohort-specific geometry to create cohort-averaged WSS maps. A Wilcoxon rank sum test was used to generate aortic P-value maps (P<0.05) representing regional relative WSS differences between groups. Results Cohort-averaged systolic WSS maps and P-value maps were successfully created for all cohorts and comparisons. The dilation cohort showed significantly lower WSS on 7% of the ascending aorta surface, whereas the stenosis cohort showed significantly higher WSS aorta on 34% the ascending aorta surface. Conclusions The findings of this study demonstrated the feasibility of generating cohort-averaged WSS maps for the visualization and identification of regionally altered WSS in the presence of disease, as compared to healthy controls. PMID:24753241

Robust best linear estimator for Cox regression with instrumental variables in whole cohort and surrogates with additive measurement error in calibration sample

PubMed Central

Wang, Ching-Yun; Song, Xiao

2017-01-01

SUMMARY Biomedical researchers are often interested in estimating the effect of an environmental exposure in relation to a chronic disease endpoint. However, the exposure variable of interest may be measured with errors. In a subset of the whole cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies an additive measurement error model, but it may not have repeated measurements. The subset in which the surrogate variables are available is called a calibration sample. In addition to the surrogate variables that are available among the subjects in the calibration sample, we consider the situation when there is an instrumental variable available for all study subjects. An instrumental variable is correlated with the unobserved true exposure variable, and hence can be useful in the estimation of the regression coefficients. In this paper, we propose a nonparametric method for Cox regression using the observed data from the whole cohort. The nonparametric estimator is the best linear combination of a nonparametric correction estimator from the calibration sample and the difference of the naive estimators from the calibration sample and the whole cohort. The asymptotic distribution is derived, and the finite sample performance of the proposed estimator is examined via intensive simulation studies. The methods are applied to the Nutritional Biomarkers Study of the Women’s Health Initiative. PMID:27546625

Incidence of Schizophrenia Among Second-Generation Immigrants in the Jerusalem Perinatal Cohort

PubMed Central

Corcoran, Cheryl; Perrin, Mary; Harlap, Susan; Deutsch, Lisa; Fennig, Shmuel; Manor, Orly; Nahon, Daniella; Kimhy, David; Malaspina, Dolores; Susser, Ezra

2009-01-01

Objective: Increased incidence of schizophrenia is observed among some immigrant groups in Europe, with the offspring of immigrants, ie “second-generation” immigrants particularly vulnerable. Few contemporary studies have evaluated the risk of schizophrenia among second-generation immigrants in other parts of the world. Methods: We studied the incidence of schizophrenia in relation to parental immigrant status in a population-based cohort of 88 829 offspring born in Jerusalem in 1964–1976. Parental countries of birth were obtained from birth certificates and grouped together as (1) Israel, (2) Other West Asia, (3) North Africa, and (4) Europe and industrialized countries. Cox proportional hazards methods were used in adjusting for sex, parents’ ages, maternal education, social class, and birth order. Results: Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. Incidence of schizophrenia was not increased among second-generation immigrants in this birth cohort, neither overall nor by specific group. Conclusions: The difference in risk of schizophrenia among second-generation immigrants in Europe and in this Israeli birth cohort suggests that the nature of the immigration experience may be relevant to risk, including reasons for migration, the nature of entry, and subsequent position in the host country for immigrants and their offspring. Minority status may be of importance as, in later studies, immigrants to Israel from Ethiopia had increased risk of schizophrenia. PMID:18648022

The sleep architecture of Saudi Arabian patients with Kleine-Levin syndrome

PubMed Central

Al Shareef, Saad M.; Almeneessier, Aljohara S.; Hammad, Omeima; Smith, Richard M.; BaHammam, Ahmed S.

2018-01-01

Objectives: To establish baseline sleep architecture during an acute attack of Kleine-Levin syndrome (KLS) in a cohort of Saudi Arabian KLS patients and compare these characteristics with other published cohorts. Methods: This was a retrospective cohort study of the polysomnographic characteristics of 10 typical symptomatic Saudi Arabian KLS patients attending the University Sleep Disorders Center, King Saud University, Riyadh, Saudi Arabia between 2002 and 2015. Data were captured by nocturnal polysomnography during an acute attack of hypersomnia and compared with other published cohorts identified via a systematic literature search. Results: Self-reported time asleep during episodes (11.1±6.7 hours) and recorded total sleep time (TST) (322.5±108.7 minutes) were generally shorter than other published cohorts. Sleep efficiency was poor at 75.0%±25.1%, with low relative amounts of rapid eye movement (REM) sleep (16.5±5.9% of TST) and deep non-REM sleep (stage N3; 10.5±6.0% of TST) and high relative amounts of non-REM sleep (stage N1; 7.0±4.3% of TST). The sleep architecture of Saudi Arabian KLS patients was similar to other published cohorts. Conclusions: Sleep architecture of our cohort was relatively normal and broadly similar to other published studies, the main features being low sleep efficiency and low relative amounts of REM and stage N3 sleep. Time-course polysomnography studies with functional imaging may be useful to further establish the exact pathophysiology of this disease. PMID:29332107

Associations between sleep bruxism and (peri-) implant complications: a prospective cohort study

PubMed Central

Thymi, Magdalini; Visscher, Corine M; Yoshida-Kohno, Eiko; Crielaard, Wim; Wismeijer, Daniel; Lobbezoo, Frank

2017-01-01

Objectives/Aims: To describe the protocol of a prospective cohort study designed to answer the question: ‘Is sleep bruxism a risk factor for (peri-)implant complications?’. Materials and Methods: Our study is a single-centre, double-blind, prospective cohort study with a follow-up time of 2 years. Ninety-eight participants fulfilling inclusion criteria (planned treatment with implant-supported fixed suprastructure(s) and age 18 years or older) will be included. Sleep bruxism will be monitored at several time points as masticatory muscle activity during sleep by means of a portable single-channel electromyographic device. Our main outcomes are biological complications (i.e., related to peri-implant bleeding, probing depth, marginal bone height, quality of submucosal biofilm and loss of osseointegration) and technical complications (i.e., suprastructure, abutment, implant body or other). Results: The study is currently ongoing, and data are being gathered. Discussion: The results of this prospective cohort study will provide important information for clinicians treating bruxing patients with dental implants. Furthermore, it will contribute to the body of evidence related to the behaviour of dental implants and their complications under conditions of high mechanical loadings that result from sleep bruxism activity. Conclusion: The protocol of a prospective cohort study designed to investigate possible associations between sleep bruxism and (peri-) implant complications was presented. PMID:29607076

Methods to Develop an Electronic Medical Record Phenotype Algorithm to Compare the Risk of Coronary Artery Disease across 3 Chronic Disease Cohorts

PubMed Central

Liao, Katherine P.; Ananthakrishnan, Ashwin N.; Kumar, Vishesh; Xia, Zongqi; Cagan, Andrew; Gainer, Vivian S.; Goryachev, Sergey; Chen, Pei; Savova, Guergana K.; Agniel, Denis; Churchill, Susanne; Lee, Jaeyoung; Murphy, Shawn N.; Plenge, Robert M.; Szolovits, Peter; Kohane, Isaac; Shaw, Stanley Y.; Karlson, Elizabeth W.; Cai, Tianxi

2015-01-01

Background Typically, algorithms to classify phenotypes using electronic medical record (EMR) data were developed to perform well in a specific patient population. There is increasing interest in analyses which can allow study of a specific outcome across different diseases. Such a study in the EMR would require an algorithm that can be applied across different patient populations. Our objectives were: (1) to develop an algorithm that would enable the study of coronary artery disease (CAD) across diverse patient populations; (2) to study the impact of adding narrative data extracted using natural language processing (NLP) in the algorithm. Additionally, we demonstrate how to implement CAD algorithm to compare risk across 3 chronic diseases in a preliminary study. Methods and Results We studied 3 established EMR based patient cohorts: diabetes mellitus (DM, n = 65,099), inflammatory bowel disease (IBD, n = 10,974), and rheumatoid arthritis (RA, n = 4,453) from two large academic centers. We developed a CAD algorithm using NLP in addition to structured data (e.g. ICD9 codes) in the RA cohort and validated it in the DM and IBD cohorts. The CAD algorithm using NLP in addition to structured data achieved specificity >95% with a positive predictive value (PPV) 90% in the training (RA) and validation sets (IBD and DM). The addition of NLP data improved the sensitivity for all cohorts, classifying an additional 17% of CAD subjects in IBD and 10% in DM while maintaining PPV of 90%. The algorithm classified 16,488 DM (26.1%), 457 IBD (4.2%), and 245 RA (5.0%) with CAD. In a cross-sectional analysis, CAD risk was 63% lower in RA and 68% lower in IBD compared to DM (p<0.0001) after adjusting for traditional cardiovascular risk factors. Conclusions We developed and validated a CAD algorithm that performed well across diverse patient populations. The addition of NLP into the CAD algorithm improved the sensitivity of the algorithm, particularly in cohorts where the prevalence of CAD was low. Preliminary data suggest that CAD risk was significantly lower in RA and IBD compared to DM. PMID:26301417

Failure to Thrive in the Term and Preterm Infants of Mothers Depressed in the Postnatal Period: A Population-Based Birth Cohort Study

ERIC Educational Resources Information Center

Drewett, Robert; Blair, Peter; Emmett, Pauline; Emond, Alan

2004-01-01

Aims: To examine the relationship between failure to thrive in preterm and term infants and postnatal depression in their mothers. Method: In a whole population birth cohort of 12,391 infants (excluding those born after term or with major congenital abnormalities) failure to thrive over the first nine months was identified using a conditional…

Severe disease presentation and poor outcomes among pediatric systemic lupus erythematosus patients in South Africa

PubMed Central

Lewandowski, Laura B; Schanberg, Laura E; Thielman, Nathan; Phuti, Angel; Kalla, Asgar A; Okpechi, Ikechi; Nourse, Peter; Gajjar, Priya; Faller, Gail; Ambaram, Priya; Reuter, Helmuth; Spittal, Graeme; Scott, Christiaan

2016-01-01

Background Systemic Lupus Erythematosus (SLE) is a life-threatening multisystem autoimmune disease that is more severe in patients of African ancestry and children, yet pediatric SLE (pSLE) on the African continent has been understudied. This study describes a cohort of pediatric SLE (PULSE) patients in South Africa (SA). Methods Patients with a diagnosis of SLE (1997 American College of Rheumatology criteria) diagnosed prior to age 19 years in Cape Town, South Africa, were enrolled in this cross-sectional study from September 2013 to December 2014. Information on clinical and serologic characteristics was extracted from medical records. Results were compared to a well-described North American pSLE cohort. Results Seventy-two SA patients were enrolled in the study; mean age 11.5 years, 82% female. The racial distribution was 68% Coloured, 24% Black, 5% White, and 3% Asian/Indian. Most patients presented with severe lupus nephritis (LN) documented by renal biopsy (61%). Of patients with LN, 63% presented with International Society of Nephrology/Renal Pathology Society (ISN/RPS) class III or IV. Patients in the PULSE cohort were more likely to be treated with cyclophosphamide, methotrexate, and azathioprine. The PULSE cohort had high disease activity at diagnosis (mean Systemic Lupus Erythematosus Disease Activity Index-2K [SLEDAI-2K] 20.6). The SLEDAI-2K at enrollment in the PULSE cohort (5.0) did not differ from the North American pSLE cohort (4.8). Sixty three % of PULSE cohort had end organ damage with System Lupus International Collaborating Clinic-Damage Index (SLICC-DI) score >0 (mean SLICC-DI 1.9), compared to 23% in a previously reported US cohort. Within the PULSE cohort, 9 (13%) developed ESRD with 6 (8%) requiring transplant, strikingly higher than North American peers (transplant rate <1%). Conclusions The PULSE cohort had highly active multiorgan disease at diagnosis and significant disease damage at enrollment in the SA registry. SA patients have severe lupus nephritis and poor renal outcomes compared to North American peers. Our study reveals a severe disease phenotype in the PULSE cohort resulting in poor outcomes in this high-risk population. PMID:27488473

Severe disease presentation and poor outcomes among pediatric systemic lupus erythematosus patients in South Africa.

PubMed

Lewandowski, L B; Schanberg, L E; Thielman, N; Phuti, A; Kalla, A A; Okpechi, I; Nourse, P; Gajjar, P; Faller, G; Ambaram, P; Reuter, H; Spittal, G; Scott, C

2017-02-01

Background Systemic lupus erythematosus (SLE) is a life-threatening multisystem autoimmune disease that is more severe in patients of African ancestry and children, yet pediatric SLE on the African continent has been understudied. This study describes a cohort of pediatric SLE (PULSE) patients in South Africa. Methods Patients with a diagnosis of SLE (1997 American College of Rheumatology criteria) diagnosed prior to age 19 years in Cape Town, South Africa, were enrolled in this cross-sectional study from September 2013 to December 2014. Information on clinical and serological characteristics was extracted from medical records. Results were compared to a well-described North American pediatric SLE cohort. Results Seventy-two South African patients were enrolled in the study; mean age 11.5 years; 82% were girls. The racial distribution was 68% Coloured, 24% Black, 5% White and 3% Asian/Indian. Most patients presented with severe lupus nephritis documented by renal biopsy (61%). Of patients with lupus nephritis, 63% presented with International Society of Nephrology/Renal Pathology Society class III or IV. Patients in the PULSE cohort were more likely to be treated with cyclophosphamide, methotrexate and azathioprine. The PULSE cohort had high disease activity at diagnosis (mean Systemic Lupus Erythematosus Disease Activity Index-2K (SLEDAI-2K) 20.6). The SLEDAI-2K at enrolment in the PULSE cohort (5.0) did not differ from the North American pediatric SLE cohort (4.8). Sixty-three per cent of the PULSE cohort had end organ damage with Systemic Lupus International Collaborating Clinics Damage Index (SLICC-DI) score >0 (mean SLICC-DI 1.9), compared to 23% in a previously reported US cohort. Within the PULSE cohort, nine (13%) developed end-stage renal disease with six (8%) requiring transplant, strikingly higher than North American peers (transplant rate <1%). Conclusions The PULSE cohort had highly active multiorgan disease at diagnosis and significant disease damage at enrolment in the South African registry. South African patients have severe lupus nephritis and poor renal outcomes compared to North American peers. Our study revealed a severe disease phenotype in the PULSE cohort resulting in poor outcomes in this high-risk population.

Clinical effect of molecular methods in sarcoma diagnosis (GENSARC): a prospective, multicentre, observational study.

PubMed

Italiano, Antoine; Di Mauro, Ilaria; Rapp, Jocelyn; Pierron, Gaëlle; Auger, Nathalie; Alberti, Laurent; Chibon, Frédéric; Escande, Fabienne; Voegeli, Anne-Claire; Ghnassia, Jean-Pierre; Keslair, Frédérique; Laé, Marick; Ranchère-Vince, Dominique; Terrier, Philippe; Baffert, Sandrine; Coindre, Jean-Michel; Pedeutour, Florence

2016-04-01

Advances in molecular genetics of sarcoma have enabled the identification of type-specific aberrations. We aimed to assess the clinical effect of systematic implementation of molecular assays to improve sarcoma misdiagnosis. In this multicentre, observational study, we recruited patients from 32 centres of the French Sarcoma Group/Reference Network in Pathology of Sarcomas. Eligibility criteria included: biopsy or surgical resection; suspicion of: dermatofibrosarcoma protuberans (cohort 1), dedifferentiated liposarcoma (cohort 2), Ewing's sarcoma family of tumours (cohort 3), synovial sarcoma (cohort 4), alveolar rhabdomyosarcoma (cohort 5), and myxoid or round cell liposarcoma (cohort 6); review by one sarcoma-expert pathologist; availability of frozen material (except for cohort 1 of patients with dermatofibrosarcoma protuberans because anti-CD34 immunohistochemistry is performed on paraffin-embedded tissue); and patient information. For each case, the pathologist made one primary diagnosis followed by up to two differential diagnoses, based on histological characteristics only. Each diagnosis was classified as certain, probable, or possible. For each case to determine the molecular classification, we did fluorescence in-situ hybridisation on paraffin-embedded samples. We also did comparative genomic hybridisation and quantitative PCR (cohort 2) or reverse transcriptase PCR (cohorts 3-6) on frozen and paraffin-embedded samples. We made a final diagnosis based on the molecular results. The clinical effect of diagnosis correction was assessed by a board of experts. Between June 22, 2009, and Oct 30, 2012, 395 patients were enrolled in the study, of which 384 were eligible for inclusion. The diagnosis was eventually modified by molecular genetics for 53 patients: eight (16%) of 50 patients with dermatofibrosarcoma (cohort 1), seven (23%) of 30 patients with dedifferentiated liposarcoma (cohort 2), 13 (12%) of 112 with Ewing's sarcoma family of tumours (cohort 3), 16 (16%) of 97 patients with synovial sarcoma (cohort 4), seven (15%) of 46 patients with alveolar rhabdomyosarcoma (cohort 5), and two (4%) of 49 patients with myxoid or round cell liposarcoma (cohort 6), with an effect on primary management or prognosis assessment in 45 cases. Molecular genetic testing should be mandatory for diagnostic accuracy of sarcoma and appropriate clinical management, even when histological diagnosis is made by pathologist experts in this field. French National Cancer Institute and Nice University Hospital. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of Highly Active Antiretroviral Therapy in a Cohort of HIV-Seropositive Women

PubMed Central

Cook, Judith A.; Cohen, Mardge H.; Grey, Dennis; Kirstein, Lynn; Burke, Jane; Anastos, Kathryn; Palacio, Herminia; Richardson, Jean; Wilson, Tracey E.; Young, Mary

2002-01-01

Objectives. This study examined longitudinal trends in use of highly active antiretroviral therapy (HAART) among a cohort of HIV-positive participants in the Women's Interagency HIV Study. Methods. Beginning in 1994, 1690 HIV-positive women reported detailed information about their use of antiretroviral therapy at 6-month study visits. Multivariate logistic and Cox regression analyses were used to estimate the likelihood of antiretroviral therapy and HAART use among women with study visits preceding and following HAART availability. Results. Before the availability of HAART, the cohort's likelihood of any antiretroviral therapy use was associated with clinical indicators (CD4 count, viral load, symptom presence) as well as behavioral factors (abstaining from drug and alcohol use, participating in clinical trials). After HAART became commercially available, newly emerging predictors included college education, private insurance, absence of injection drug use history, and not being African American. Conclusions. After the penetration of HAART into this cohort, additional differences emerged between HAART users and nonusers. These findings can inform public health efforts to enhance women's access to the most effective types of therapy. PMID:11772767

A Comparison of Different Methods for Evaluating Diet, Physical Activity, and Long-Term Weight Gain in 3 Prospective Cohort Studies123

PubMed Central

Smith, Jessica D; Hou, Tao; Hu, Frank B; Rimm, Eric B; Spiegelman, Donna; Willett, Walter C; Mozaffarian, Dariush

2015-01-01

Background: The insidious pace of long-term weight gain (∼1 lb/y or 0.45 kg/y) makes it difficult to study in trials; long-term prospective cohorts provide crucial evidence on its key contributors. Most previous studies have evaluated how prevalent lifestyle habits relate to future weight gain rather than to lifestyle changes, which may be more temporally and physiologically relevant. Objective: Our objective was to evaluate and compare different methodological approaches for investigating diet, physical activity (PA), and long-term weight gain. Methods: In 3 prospective cohorts (total n = 117,992), we assessed how lifestyle relates to long-term weight change (up to 24 y of follow-up) in 4-y periods by comparing 3 analytic approaches: 1) prevalent diet and PA and 4-y weight change (prevalent analysis); 2) 4-y changes in diet and PA with a 4-y weight change (change analysis); and 3) 4-y change in diet and PA with weight change in the subsequent 4 y (lagged-change analysis). We compared these approaches and evaluated the consistency across cohorts, magnitudes of associations, and biological plausibility of findings. Results: Across the 3 methods, consistent, robust, and biologically plausible associations were seen only for the change analysis. Results for prevalent or lagged-change analyses were less consistent across cohorts, smaller in magnitude, and biologically implausible. For example, for each serving of a sugar-sweetened beverage, the observed weight gain was 0.01 lb (95% CI: −0.08, 0.10) [0.005 kg (95% CI: −0.04, 0.05)] based on prevalent analysis; 0.99 lb (95% CI: 0.83, 1.16) [0.45 kg (95% CI: 0.38, 0.53)] based on change analysis; and 0.05 lb (95% CI: −0.10, 0.21) [0.02 kg (95% CI: −0.05, 0.10)] based on lagged-change analysis. Findings were similar for other foods and PA. Conclusions: Robust, consistent, and biologically plausible relations between lifestyle and long-term weight gain are seen when evaluating lifestyle changes and weight changes in discrete periods rather than in prevalent lifestyle or lagged changes. These findings inform the optimal methods for evaluating lifestyle and long-term weight gain and the potential for bias when other methods are used. PMID:26377763

Combination nivolumab and ipilimumab or nivolumab alone in melanoma brain metastases: a multicentre randomised phase 2 study.

PubMed

Long, Georgina V; Atkinson, Victoria; Lo, Serigne; Sandhu, Shahneen; Guminski, Alexander D; Brown, Michael P; Wilmott, James S; Edwards, Jarem; Gonzalez, Maria; Scolyer, Richard A; Menzies, Alexander M; McArthur, Grant A

2018-05-01

Nivolumab monotherapy and combination nivolumab plus ipilimumab increase proportions of patients achieving a response and survival versus ipilimumab in patients with metastatic melanoma; however, efficacy in active brain metastases is unknown. We aimed to establish the efficacy and safety of nivolumab alone or in combination with ipilimumab in patients with active melanoma brain metastases. This multicentre open-label randomised phase 2 trial was done at four sites in Australia, in three cohorts of immunotherapy-naive patients aged 18 years or older with melanoma brain metastases. Patients with asymptomatic brain metastases with no previous local brain therapy were randomly assigned using the biased coin minimisation method, stratified by site, in a 30:24 ratio (after a safety run-in of six patients) to cohort A (nivolumab plus ipilimumab) or cohort B (nivolumab). Patients with brain metastases in whom local therapy had failed, or who had neurological symptoms, or leptomeningeal disease were enrolled in non-randomised cohort C (nivolumab). Patients in cohort A received intravenous nivolumab 1 mg/kg combined with ipilimumab 3 mg/kg every 3 weeks for four doses, then nivolumab 3 mg/kg every 2 weeks; patients in cohort B or cohort C received intravenous nivolumab 3 mg/kg every 2 weeks. The primary endpoint was intracranial response from week 12. Primary and safety analyses were done on an intention-to-treat basis in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, number NCT02374242, and is ongoing for the final survival analysis. Between Nov 4, 2014, and April 21, 2017, 79 patients were enrolled; 36 in cohort A, 27 in cohort B, and 16 in cohort C. One patient in cohort A and two in cohort B were found to be ineligible and excluded from the study before receiving the study drug. At the data cutoff (Aug 28, 2017), with a median follow up of 17 months (IQR 8-25), intracranial responses were achieved by 16 (46%; 95% CI 29-63) of 35 patients in cohort A, five (20%; 7-41) of 25 in cohort B, and one (6%; 0-30) of 16 in cohort C. Intracranial complete responses occurred in six (17%) patients in cohort A, three (12%) in cohort B, and none in cohort C. Treatment-related adverse events occurred in 34 (97%) of 35 patients in cohort A, 17 (68%) of 25 in cohort B, and eight (50%) of 16 in cohort C. Grade 3 or 4 treatment-related adverse events occurred in 19 (54%) patients in cohort A, four (16%) in cohort B, and two (13%) in cohort C. No treatment-related deaths occurred. Nivolumab combined with ipilimumab and nivolumab monotherapy are active in melanoma brain metastases. A high proportion of patients achieved an intracranial response with the combination. Thus, nivolumab combined with ipilimumab should be considered as a first-line therapy for patients with asymptomatic untreated brain metastases. Melanoma Institute Australia and Bristol-Myers Squibb. Copyright © 2018 Elsevier Ltd. All rights reserved.

Alterations of the Subgingival Microbiota in Pediatric Crohn's Disease Studied Longitudinally in Discovery and Validation Cohorts

PubMed Central

Kelsen, Judith; Bittinger, Kyle; Pauly-Hubbard, Helen; Posivak, Leah; Grunberg, Stephanie; Baldassano, Robert; Lewis, James D; Wu, Gary D; Bushman, Frederic D

2016-01-01

Background Oral manifestations are common in Crohn's disease (CD). Here we characterized the subgingival microbiota in pediatric CD patients initiating therapy and after 8 weeks to identify microbial community features associated with CD and therapy. Methods Pediatric CD patients were recruited from The Children's Hospital of Pennsylvania. Healthy control subjects were recruited from primary care or orthopedics clinic. Subgingival plaque samples were collected at initiation of therapy and after 8 weeks. Treatment exposures included 5-ASAs, immunomodualtors, steroids, and infliximab. The microbiota was characterized by 16S rRNA gene sequencing. The study was repeated in separate discovery (35 CD, 43 healthy) and validation cohorts (43 CD, 31 healthy). Results A majority of subjects in both cohorts demonstrated clinical response after 8 weeks of therapy (discovery cohort 88%, validation cohort 79%). At week 0, both antibiotic exposure and disease state were associated with differences in bacterial community composition. Seventeen genera were identified in the discovery cohort as candidate biomarkers, of which 11 were confirmed in the validation cohort. Capnocytophaga, Rothia, and TM7 were more abundant in CD relative to healthy controls. Other bacteria were reduced in abundance with antibiotic exposure among CD subjects. CD-associated genera were not enriched compared to healthy controls after 8 weeks of therapy. Conclusions Subgingival microbial community structure differed with CD and antibiotic use. Results in the discovery cohort were replicated in a separate validation cohort. Several potentially pathogenic bacterial lineages were associated with CD but were not diminished in abundance by antibiotic treatment, suggesting targets for additional surveillance. PMID:26288001

Studies on Early Allergic Sensitization in the Lithuanian Birth Cohort

PubMed Central

Dubakiene, Ruta; Rudzeviciene, Odilija; Butiene, Indre; Sezaite, Indre; Petronyte, Malvina; Vaicekauskaite, Dalia; Zvirbliene, Aurelija

2012-01-01

Cohort studies are of great importance in defining the mechanism responsible for the development of allergy-associated diseases, such as atopic dermatitis, allergic asthma, and allergic rhinoconjunctivitis. Although these disorders share genetic and environmental risk factors, it is still under debate whether they are linked or develop sequentially along an atopic pathway. The current study was aimed to determine the pattern of allergy sensitization in the Lithuanian birth cohort “Alergemol” (n = 1558) established as a part of the multicenter European birth cohort “EuroPrevall”. Early sensitization to food allergens in the “Alergemol” birth cohort was analysed. The analysis revealed 1.3% and 2.8% of symptomatic-sensitized subjects at 6 and 12 months of age, respectively. The sensitization pattern in response to different allergens in the group of infants with food allergy symptoms was studied using allergological methods in vivo and in vitro. The impact of maternal and environmental risk factors on the early development of food allergy in at 6 and 12 months of age was evaluated. Our data showed that maternal diet, diseases, the use of antibiotics, and tobacco smoke during pregnancy had no significant impact on the early sensitization to food allergens. However, infants of atopic mothers were significantly more often sensitized to egg as compared to the infants of nonatopic mothers. PMID:22606067

Study protocol title: a prospective cohort study of low back pain.

PubMed

Garg, Arun; Hegmann, Kurt T; Moore, J Steven; Kapellusch, Jay; Thiese, Matthew S; Boda, Sruthi; Bhoyr, Parag; Bloswick, Donald; Merryweather, Andrew; Sesek, Richard; Deckow-Schaefer, Gwen; Foster, James; Wood, Eric; Sheng, Xiaoming; Holubkov, Richard

2013-03-07

Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors. A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs. Due to the subjectivity of LBP, six measures of LBP are captured: 1) any LBP, 2) LBP ≥ 5/10 pain rating, 3) LBP with medication use, 4) LBP with healthcare provider visits, 5) LBP necessitating modified work duties and 6) LBP with lost work time. Workers have thus far been enrolled from 30 different employment settings in 4 diverse US states and performed widely varying work. At baseline, workers undergo laptop-administered questionnaires, structured interviews, and two standardized physical examinations to ascertain demographics, medical history, psychosocial factors, hobbies and physical activities, and current musculoskeletal disorders. All workers' jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of low back pain. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. The lifetime cumulative incidence of low back pain will also include those with a past history of low back pain. Incident cases will exclude prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression. Data analysis of a prospective cohort study of low back pain is underway and has successfully enrolled over 800 workers to date.

Clopidogrel treatment on the incidence and severity of community acquired pneumonia in a cohort study and meta-analysis of antiplatelet therapy in pneumonia and critical illness

PubMed Central

Gross, A. Kendall; Dunn, Steven P.; Feola, David J.; Martin, Craig A.; Charnigo, Richard; Li, Zhenyu; Abdel-Latif, Ahmed; Smyth, Susan S.

2013-01-01

Background Platelet activation results in the release and upregulation of mediators responsible for immune cell activation and recruitment, suggesting that platelets play an active role in immunity. Animal models and retrospective data have demonstrated benefit of antiplatelet therapy on inflammatory mediator expression and clinical outcomes. This study sought to characterize effects of clopidogrel on the incidence and severity of community-acquired pneumonia (CAP). Methods A retrospective cohort study was conducted of Kentucky Medicaid patients (2001-2005). The exposed cohort consisted of patients receiving at least six consecutive clopidogrel prescriptions; the non-exposed cohort was comprised of patients not prescribed clopidogrel. Primary endpoints included incidence of CAP and inpatient treatment. Secondary severity endpoints included mortality, intensive care unit admission, mechanical ventilation, sepsis, and acute respiratory distress syndrome/acute lung injury. Results CAP incidence was significantly greater in the exposed cohort (OR 3.39, 95% CI 3.27-3.51, p < 0.0001) that remained after adjustment (OR 1.48, 95% CI 1.41-1.55, p < 0.0001). Inpatient treatment was more common in the exposed cohort (OR 1.96, 95% CI 1.85-2.07, p < 0.0001), but no significant difference remained after adjustment. Trends favoring the exposed cohort were found for the secondary severity endpoints of mechanical ventilation (p = 0.07) and mortality (p = 0.10). Pooled analysis of published studies supports these findings. Conclusions While clopidogrel use may be associated with increased CAP incidence, clopidogrel does not appear to increase – and may reduce – its severity among inpatients. Because this study was retrospective and could not quantify all variables (e.g., aspirin use), these findings should be explored prospectively. PMID:23124575

Low Serum Vitamin D Levels Are Associated With Inferior Survival in Follicular Lymphoma: A Prospective Evaluation in SWOG and LYSA Studies

PubMed Central

Kelly, Jennifer L.; Salles, Gilles; Goldman, Bryan; Fisher, Richard I.; Brice, Pauline; Press, Oliver; Casasnovas, Olivier; Maloney, David G.; Soubeyran, Pierre; Rimsza, Lisa; Haioun, Corinne; Xerri, Luc; LeBlanc, Michael; Tilly, Hervé; Friedberg, Jonathan W.

2015-01-01

Purpose Recent literature reports a potential association between high vitamin D and improved lymphoma prognosis. We evaluated the impact of pretreatment vitamin D on follicular lymphoma (FL) outcome. Patients and Methods SWOG participants were previously untreated patients with FL enrolled onto SWOG clinical trials (S9800, S9911, or S0016) involving CHOP chemotherapy plus an anti-CD20 antibody (rituximab or iodine-131 tositumomab) between 1998 and 2008. Participants included in our second independent cohort were also previously untreated patients with FL enrolled onto the Lymphoma Study Association (LYSA) PRIMA trial of rituximab plus chemotherapy (randomly assigned to rituximab maintenance v observation) between 2004 and 2007. Using the gold-standard liquid chromatography–tandem mass spectrometry method, 25-hydroxyvitamin D was measured in stored baseline serum samples. The primary end point was progression-free survival (PFS). Results After a median follow-up of 5.4 years, the adjusted PFS and overall survival hazard ratios for the SWOG cohort were 1.97 (95% CI, 1.10 to 3.53) and 4.16 (95% CI, 1.66 to 10.44), respectively, for those who were vitamin D deficient (< 20 ng/mL; 15% of cohort). After a median follow-up of 6.6 years, the adjusted PFS and overall survival hazard ratios for the LYSA cohort were 1.50 (95% CI, 0.93 to 2.42) and 1.92 (95% CI, 0.72 to 5.13), respectively, for those who were vitamin D deficient (< 10 ng/mL; 25% of cohort). Conclusion Although statistical significance was not reached in the LYSA cohort, the consistent estimates of association between low vitamin D levels and FL outcomes in two independent cohorts suggests that serum vitamin D might be the first potentially modifiable factor to be associated with FL survival. Further investigation is needed to determine the effects of vitamin D supplementation in this clinical setting. PMID:25823738

The risk of cryptorchidism among sons of women working in horticulture in Denmark: a cohort study

PubMed Central

2011-01-01

Background Androgens are crucial for normal testicular descent. Studies show that some pesticides have estrogenic or antiandrogenic effects, and that female workers exposed to pesticides have increased risk of having a boy with cryptorchidism. The main objective of the present study was to investigate whether pregnant women exposed to pesticides due to their work in horticulture experience excess risk of having sons with cryptorchidism. Methods We conducted a cohort study of pregnant women working in horticulture using four cohorts including one cohort established with data from the departments of occupational medicine in Jutland and Funen and three existing mother-child cohorts (n = 1,468). A reference group was established from the entire Danish population of boys born in the period of 1986-2007 (n = 783,817). Nationwide Danish health registers provided information on birth outcome, cryptorchidism diagnosis and orchiopexy. The level of occupational exposure to pesticides was assessed by expert judgment blinded towards outcome status. Risk of cryptorchidism among exposed horticulture workers compared to the background population and to unexposed horticulture workers was assessed by Cox regression models. Results Pesticide exposed women employed in horticulture had a hazard ratio (HR) of having cryptorchid sons of 1.39 (95% CI 0.84; 2.31) and a HR of orchiopexy of 1.34 (0.72; 2.49) compared to the background population. Analysis divided into separate cohorts revealed a significantly increased risk of cryptorchidism in cohort 2: HR 2.58 (1.07;6.20) and increased risk of orchiopexy in cohort 4: HR 2.76 (1.03;7.35), but no significant associations in the other cohorts. Compared to unexposed women working in horticulture, pesticide exposed women had a risk of having sons with cryptorchidism of 1.34 (0.30; 5.96) and of orchiopexy of 1.93 (0.24;15.4). Conclusions The data are compatible with a slightly increased risk of cryptorchidism in sons of women exposed to pesticides by working in horticulture. PMID:22082298

Trends in patterns of dengue transmission over four years of a pediatric cohort study in Nicaragua

PubMed Central

Balmaseda, Angel; Standish, Katherine; Mercado, Juan Carlos; Matute, Juan Carlos; Tellez, Yolanda; Saborío, Saira; Hammond, Samantha N.; Nuñez, Andrea; Avilés, William; Henn, Matthew R.; Holmes, Edward C.; Gordon, Aubree; Coloma, Josefina; Kuan, Guillermina; Harris, Eva

2013-01-01

Background Dengue is the most prevalent mosquito-borne viral disease in humans and a major urban public health problem worldwide. Methods A prospective cohort study of ~3,800 children initially aged 2-9 years old was established in Managua, Nicaragua, in 2004 to study the natural history of dengue transmission in an urban pediatric population. Blood samples from healthy subjects were collected annually prior to the dengue season, and identification of dengue cases occurred via enhanced passive surveillance at the study health center. Results Over the first four years of the study, seroprevalence of anti-dengue virus (DENV) antibodies increased from 22-40% in the 2-year-old cohort and 90-95% in the 9-year-old cohort. The incidence of symptomatic dengue cases and the ratio of inapparent to symptomatic DENV infection varied substantially year-to-year. The switch in dominant transmission from DENV-1 to DENV-2 was accompanied by an increase in disease severity but, paradoxically, a decrease in transmission. Phylogeographic analysis of full-length DENV-2 sequences revealed strong geographic clustering of dengue cases. Conclusions This large-scale cohort study of dengue in the Americas demonstrates year-to-year variation of dengue within a pediatric population, revealing expected patterns in transmission while highlighting the impact of interventions, climate, and viral evolution. PMID:19929380

Relative survival: a useful tool to assess generalisability in longitudinal studies of health in older persons

PubMed Central

2011-01-01

Background Generalisability of longitudinal studies is threatened by issues such as choice of sampling frame, representativeness of the initial sample, and attrition. To determine representativeness, cohorts are often compared with the population of interest at baseline on demographic and health characteristics. This study illustrates the use of relative survival as a tool for assessing generalisability of results from a cohort of older people among whom death is a potential threat to generalisability. Methods The authors used data from the 1921-26 cohort (n = 12,416, aged 70-75 in 1996) of the Australian Longitudinal Study on Women's Health (ALSWH). Vital status was determined by linkage to the National Death Index, and expected deaths were derived using Australian life tables. Relative survival was estimated using observed survival in the cohort divided by expected survival among women of the same age and State or Territory. Results Overall, the ALSWH women showed relative survival 9.5% above the general population. Within States and Territories, the relative survival advantage varied from 6% to 23%. The interval-specific relative survival remained relatively constant over the 12 years (1996-2008) under review, indicating that the survival advantage of the cohort has not diminished over time. Conclusion This study demonstrates that relative survival can be a useful measure of generalisability in a longitudinal study of the health of the general population, particularly when participants are older. PMID:21294918

Risk Prediction of New Adjacent Vertebral Fractures After PVP for Patients with Vertebral Compression Fractures: Development of a Prediction Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Bin-Yan; He, Shi-Cheng; Zhu, Hai-Dong

PurposeWe aim to determine the predictors of new adjacent vertebral fractures (AVCFs) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs) and to construct a risk prediction score to estimate a 2-year new AVCF risk-by-risk factor condition.Materials and MethodsPatients with OVCFs who underwent their first PVP between December 2006 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included in this study. In training cohort, we assessed the independent risk predictors and developed the probability of new adjacent OVCFs (PNAV) score system using the Cox proportional hazard regression analysis. The accuracy ofmore » this system was then validated in both training and validation cohorts by concordance (c) statistic.Results421 patients (training cohort: n = 256; validation cohort: n = 165) were included in this study. In training cohort, new AVCFs after the first PVP treatment occurred in 33 (12.9%) patients. The independent risk factors were intradiscal cement leakage and preexisting old vertebral compression fracture(s). The estimated 2-year absolute risk of new AVCFs ranged from less than 4% in patients with neither independent risk factors to more than 45% in individuals with both factors.ConclusionsThe PNAV score is an objective and easy approach to predict the risk of new AVCFs.« less

The WISTAH hand study: a prospective cohort study of distal upper extremity musculoskeletal disorders.

PubMed

Garg, Arun; Hegmann, Kurt T; Wertsch, Jacqueline J; Kapellusch, Jay; Thiese, Matthew S; Bloswick, Donald; Merryweather, Andrew; Sesek, Richard; Deckow-Schaefer, Gwen; Foster, James; Wood, Eric; Kendall, Richard; Sheng, Xiaoming; Holubkov, Richard

2012-06-06

Few prospective cohort studies of distal upper extremity musculoskeletal disorders have been performed. Past studies have provided somewhat conflicting evidence for occupational risk factors and have largely reported data without adjustments for many personal and psychosocial factors. A multi-center prospective cohort study was incepted to quantify risk factors for distal upper extremity musculoskeletal disorders and potentially develop improved methods for analyzing jobs. Disorders to analyze included carpal tunnel syndrome, lateral epicondylalgia, medial epicondylalgia, trigger digit, deQuervain's stenosing tenosynovitis and other tendinoses. Workers have thus far been enrolled from 17 different employment settings in 3 diverse US states and performed widely varying work. At baseline, workers undergo laptop administered questionnaires, structured interviews, two standardized physical examinations and nerve conduction studies to ascertain demographic, medical history, psychosocial factors and current musculoskeletal disorders. All workers' jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of musculoskeletal disorders. Repeat nerve conduction studies are performed for those with symptoms of tingling and numbness in the prior six months. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. Case definitions have been established. Point prevalence of carpal tunnel syndrome is a combination of paraesthesias in at least two median nerve-served digits plus an abnormal nerve conduction study at baseline. The lifetime cumulative incidence of carpal tunnel syndrome will also include those with a past history of carpal tunnel syndrome. Incident cases will exclude those with either a past history or prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression. A prospective cohort study of distal upper extremity musculoskeletal disorders is underway and has successfully enrolled over 1,000 workers to date.

Survival effect of first- and second-line treatments for patients with primary glioblastoma: a cohort study from a prospective registry, 1997–2010

PubMed Central

Nava, Francesca; Tramacere, Irene; Fittipaldo, Andrea; Bruzzone, Maria Grazia; DiMeco, Francesco; Fariselli, Laura; Finocchiaro, Gaetano; Pollo, Bianca; Salmaggi, Andrea; Silvani, Antonio; Farinotti, Mariangela; Filippini, Graziella

2014-01-01

Background Prospective follow-up studies of large cohorts of patients with glioblastoma (GBM) are needed to assess the effectiveness of conventional treatments in clinical practice. We report GBM survival data from the Brain Cancer Register of the Fondazione Istituto Neurologico Carlo Besta (INCB) in Milan, Italy, which collected longitudinal data for all consecutive patients with GBM from 1997 to 2010. Methods Survival data were obtained from 764 patients (aged>16 years) with histologically confirmed primary GBM who were diagnosed and treated over a 7-year period (2004–2010) with follow-up to April 2012 (cohort II). Equivalent data from 490 GBM patients diagnosed and treated over the preceding 7 years (1997–2003) with follow-up to April 2005 (cohort I) were available for comparison. Progression-free survival (PFS) was available from 361 and 219 patients actively followed up at INCB in cohorts II and I, respectively. Results Survival probabilities were 54% at 1 year, 21% at 2 years, and 11% at 3 years, respectively, in cohort II compared with 47%, 11%, and 5%, respectively, in cohort I. PFS was 22% and 12% at 1 year in cohorts II and I. Better survival and PFS in cohort II was significantly associated with introduction of the Stupp protocol into clinical practice, with adjusted hazard ratios (HRs) of 0.78 for survival and 0.73 for PFS, or a 22% relative decrease in the risk of death and a 27% relative decrease in the risk of recurrence. After recurrence, reoperation was performed in one-fifth of cohort I and in one-third of cohort II but was not effective (HR, 1.05 in cohort I and 1.02 in cohort II). Second-line chemotherapy, mainly consisting of nitrosourea-based chemotherapy, temozolomide, mitoxantrone, fotemustine, and bevacizumab, improved survival in both cohorts (HR, 0.57 in cohort I and 0.74 in cohort II). Radiosurgery was also effective (HR, 0.52 in cohort II). Conclusions We found a significant increase in overall survival, PFS, and survival after recurrence after 2004, likely due to improvements in surgical techniques, introduction of the Stupp protocol as a first-line treatment, and new standard protocols for second-line chemotherapy and radiosurgery after tumor recurrence. In both cohorts, reoperation after tumor recurrence did not improve survival. PMID:24463354

Validation of the prognostic gene portfolio, ClinicoMolecular Triad Classification, using an independent prospective breast cancer cohort and external patient populations

PubMed Central

2014-01-01

Introduction Using genome-wide expression profiles of a prospective training cohort of breast cancer patients, ClinicoMolecular Triad Classification (CMTC) was recently developed to classify breast cancers into three clinically relevant groups to aid treatment decisions. CMTC was found to be both prognostic and predictive in a large external breast cancer cohort in that study. This study serves to validate the reproducibility of CMTC and its prognostic value using independent patient cohorts. Methods An independent internal cohort (n = 284) and a new external cohort (n = 2,181) were used to validate the association of CMTC between clinicopathological factors, 12 known gene signatures, two molecular subtype classifiers, and 19 oncogenic signalling pathway activities, and to reproduce the abilities of CMTC to predict clinical outcomes of breast cancer. In addition, we also updated the outcome data of the original training cohort (n = 147). Results The original training cohort reached a statistically significant difference (p < 0.05) in disease-free survivals between the three CMTC groups after an additional two years of follow-up (median = 55 months). The prognostic value of the triad classification was reproduced in the second independent internal cohort and the new external validation cohort. CMTC achieved even higher prognostic significance when all available patients were analyzed (n = 4,851). Oncogenic pathways Myc, E2F1, Ras and β-catenin were again implicated in the high-risk groups. Conclusions Both prospective internal cohorts and the independent external cohorts reproduced the triad classification of CMTC and its prognostic significance. CMTC is an independent prognostic predictor, and it outperformed 12 other known prognostic gene signatures, molecular subtype classifications, and all other standard prognostic clinicopathological factors. Our results support further development of CMTC portfolio into a guide for personalized breast cancer treatments. PMID:24996446

Cross-cultural comparisons of the Mini-mental State Examination between Japanese and U.S. cohorts

PubMed Central

Meguro, Kenichi; Ishii, Hiroshi; Yamaguchi, Satoshi; Saxton, Judith A.; Ganguli, Mary

2009-01-01

Background The Mini-mental State Examination (MMSE) is widely used in Japan and the U.S.A. for cognitive screening in the clinical setting and in epidemiological studies. A previous Japanese community study reported distributions of the MMSE total score very similar to that of the U.S.A. Methods Data were obtained from the Monongahela Valley Independent Elder's Study (MoVIES), a representative sample of community-dwelling elderly people aged 65 and older living near Pittsburgh, U.S.A., and from the Tajiri Project, with similar aims in Tajiri, Japan. We examined item-by-item distributions of the MMSE between two cohorts, comparing (1) percentage of correct answers for each item within each cohort, and (2) relative difficulty of each item measured by Item Characteristic Curve analysis (ICC), which estimates log odds of obtaining a correct answer adjusted for the remaining MMSE items, demographic variables (age, gender, education) and interactions of demographic variables and cohort. Results Median MMSE scores were very similar between the two samples within the same education groups. However, the relative difficulty of each item differed substantially between the two cohorts. Specifically, recall and auditory comprehension were easier for the Tajiri group, but reading comprehension and sentence construction were easier for the MoVIES group. Conclusions Our results reaffirm the importance of validation and examination of thresholds in each cohort to be studied when a common instrument is used as a dementia screening tool or for defining cognitive impairment. PMID:18925977

Review of four publications on the Danish cohort study on mobile phone subscribers and risk of brain tumors.

PubMed

Söderqvist, Fredrik; Carlberg, Michael; Hardell, Lennart

2012-01-01

Since the International Agency for Research on Cancer recently classified radiofrequency electromagnetic fields, such as those emanating from mobile and cordless phones, as possibly carcinogenic to humans (group 2B), two additional reports relevant to the topic have been published. Both articles were new updates of a Danish cohort on mobile phone subscribers and concern the possible association between assumed use of mobile phones and risk of brain tumors. The aim of the present review is to reexamine all four publications on this cohort. In brief, publications were scrutinized, and in particular, if the authors made explicit claims to have either proved or disproved their hypothesis, such claims were reviewed in light of applied methods and study design, and in principle, the stronger the claims, the more careful our review. The nationwide Danish cohort study on mobile phone subscribers and risk of brain tumors, including at best 420,095 persons (58% of the initial cohort), is the only one of its kind. In comparison with previous investigations, i.e., case-control studies, its strength lies in the possibility to eliminate non-response, selection, and recall bias. Although at least non-response and recall bias can be excluded, the study has serious limitations related to exposure assessment. In fact, these limitations cloud the findings of the four reports to such an extent that render them uninformative at best. At worst, they may be used in a seemingly solid argument against an increased risk--as reassuring results from a large nationwide cohort study, which rules out not only non-response and recall bias but also an increased risk as indicated by tight confidence intervals. Although two of the most comprehensive case-control studies on the matter both have methodological limitations that need to be carefully considered, type I errors are not the only threats to the validity of studies on this topic--the Danish cohort study is a textbook example of that.

Trends in marriage and time spent single in sub-Saharan Africa: a comparative analysis of six population-based cohort studies and nine Demographic and Health Surveys

PubMed Central

Marston, M; Slaymaker, E; Cremin, I; Floyd, S; McGrath, N; Kasamba, I; Lutalo, T; Nyirenda, M; Ndyanabo, A; Mupambireyi, Z; Żaba, B

2009-01-01

Objectives: To describe trends in age at first sex (AFS), age at first marriage (AFM) and time spent single between events and to compare age-specific trends in marital status in six cohort studies. Methods: Cohort data from Uganda, Tanzania, South Africa, Zimbabwe and Malawi and Demographic and Health Survey (DHS) data from Uganda, Tanzania and Zimbabwe were analysed. Life table methods were used to calculate median AFS, AFM and time spent single. In each study, two surveys were chosen to compare marital status by age and identify changes over time. Results: Median AFM was much higher in South Africa than in the other sites. Between the other populations there were considerable differences in median AFS and AFM (AFS 17–19 years for men and 16–19 years for women, AFM 21–24 years and 18–19 years, respectively, for the 1970–9 birth cohort). In all surveys, men reported a longer time spent single than women (median 4–7 years for men and 0–2 years for women). Median years spent single for women has increased, apart from in Manicaland. For men in Rakai it has decreased slightly over time but increased in Kisesa and Masaka. The DHS data showed similar trends to those in the cohort data. The age-specific proportion of married individuals has changed little over time. Conclusions: Median AFS, AFM and time spent single vary considerably among these populations. These three measures are underlying determinants of sexual risk and HIV infection, and they may partially explain the variation in HIV prevalence levels between these populations. PMID:19307343

Suicide Mortality Among Retired National Football League Players Who Played 5 or More Seasons

PubMed Central

Lehman, Everett J.; Hein, Misty J.; Gersic, Christine M.

2016-01-01

Background There is current disagreement in the scientific literature about the relationship between playing football and suicide risk, particularly among professional players in the National Football League (NFL). While some research indicates players are at high risk of football-related concussions, which may lead to chronic traumatic encephalopathy and suicide, other research finds such a connection to be speculative and unsupported by methodologically sound research. Purpose To compare the suicide mortality of a cohort of NFL players to what would be expected in the general population of the United States. Study Design Cohort study; Level of evidence, 3. Methods A cohort of 3439 NFL players with at least 5 credited playing seasons between 1959 and 1988 was assembled for statistical analysis. The vital status for this cohort was updated through 2013. Standardized mortality ratios (SMRs), the ratio of observed deaths to expected deaths, and 95% CIs were computed for the cohort; 95% CIs that excluded unity were considered statistically significant. For internal comparison purposes, standardized rate ratios were calculated to compare mortality results between players stratified into speed and nonspeed position types. Results Suicide among this cohort of professional football players was significantly less than would be expected in comparison with the United States population (SMR = 0.47; 95% CI, 0.24–0.82). There were no significant differences in suicide mortality between speed and nonspeed position players. Conclusion There is no indication of elevated suicide risk in this cohort of professional football players with 5 or more credited seasons of play. Because of the unique nature of this cohort, these study results may not be applicable to professional football players who played fewer than 5 years or to college or high school players. PMID:27159317

Center effect on ankle-brachial index measurement when using the reference method (Doppler and manometer): results from a large cohort study.

PubMed

Vierron, Emilie; Halimi, Jean-Michel; Tichet, Jean; Balkau, Beverley; Cogneau, Joel; Giraudeau, Bruno

2009-07-01

The ankle-brachial index (ABI) is a simple and noninvasive tool used to detect peripheral arterial disease (PAD). We aimed to assess, in a French multicenter cohort, the center effect associated with arterial pressure (AP) and ABI measurements using the reference method and using a semiautomatic device. This study included baseline and 9-year follow-up data from 3,664 volunteers of 10 health examination centers of the DESIR (Data from an Epidemiological Study on the Insulin Resistance) syndrome French cohort. Ankle and brachial AP were measured at inclusion by the reference method (a mercury sphygmomanometer coupled with a Doppler probe for ankle measurements) and at 9 years by a semiautomatic device (Omron HEM-705CP). The center effect was assessed by the intraclass correlation coefficient (ICC), ratio of the between-center variance to the total variance of the measurement. At inclusion, the sample mean age was 47.5 (s.d. 9.9) years; 49.3% were men. Although ICCs were smaller than 0.05 for brachial AP measurements, they were close to 0.18 and 0.20 for ankle systolic AP (SAP) and ABI measurements, respectively, when the reference method was used. No center effect for measures other than ankle SAP was detected. With the semiautomatic device method, all ICCs, including those for ankle SAP and ABI measurements, were between 0.005 and 0.04. We found an important center effect on ABI measured with a sphygmomanometer and a Doppler probe but not a semiautomatic device. A center effect should be taken into account when planning any multicenter study on ABI measurement.

The Sister Study Cohort: Baseline Methods and Participant Characteristics

PubMed Central

Hodgson, M. Elizabeth; Deming-Halverson, Sandra L.; Juras, Paula S.; D’Aloisio, Aimee A.; Suarez, Lourdes M.; Kleeberger, Cynthia A.; Shore, David L.; DeRoo, Lisa A.; Taylor, Jack A.; Weinberg, Clarice R.

2017-01-01

Background: The Sister Study was designed to address gaps in the study of environment and breast cancer by taking advantage of more frequent breast cancer diagnoses among women with a sister history of breast cancer and the presumed enrichment of shared environmental and genetic exposures. Objective: The Sister Study sought a large cohort of women never diagnosed with breast cancer but who had a sister (full or half) diagnosed with breast cancer. Methods: A multifaceted national effort employed novel strategies to recruit a diverse cohort, and collected biological and environmental samples and extensive data on potential breast cancer risk factors. Results: The Sister Study enrolled 50,884 U.S. and Puerto Rican women 35–74y of age (median 56 y). Although the majority were non-Hispanic white, well educated, and economically well off, substantial numbers of harder-to-recruit women also enrolled (race/ethnicity other than non-Hispanic white: 16%; no college degree: 35%; household income <$50,000: 26%). Although all had a biologic sister with breast cancer, 16.5% had average or lower risk of breast cancer according to the Breast Cancer Risk Assessment Tool (Gail score). Most were postmenopausal (66%), parous with a first full-term pregnancy <30y of age (79%), never-smokers (56%) with body mass indexes (BMIs) of <29.9 kg/m2 (70%). Few (5%) reported any cancer prior to enrollment. Conclusions: The Sister Study is a unique cohort designed to efficiently study environmental and genetic risk factors for breast cancer. Extensive exposure data over the life-course and baseline specimens provide important opportunities for studying breast cancer and other health outcomes in women. Collaborations are welcome. https://doi.org/10.1289/EHP1923 PMID:29373861

CANCER INCIDENCE IN THE AGRICULTURAL HEALTH STUDY

EPA Science Inventory

The Agricultural Health Study (AHS) was undertaken to ascertain the etiology of cancers observed to be elevated in agricultural populations. Methods: The AHS is a large prospective, cohort study of private applicators and commercial applicators licensed to apply restricted use ...

Comparisons of Body Volumes and Dimensions Using Three-Dimensional Photonic Scanning in Adult Hispanic-Americans and Caucasian-Americans

PubMed Central

Olivares, Josefina; Wang, Jack; Yu, Wen; Pereg, Vicente; Weil, Richard; Kovacs, Betty; Gallagher, Dympna; Pi-Sunyer, F. Xavier

2007-01-01

Background We studied whether significant differences exist between Hispanic-Americans (H-A) and Caucasian-Americans (C-A) in body dimensions using a newly validated three-dimensional photonic scanner (3DPS). Methods We compared two cohorts of 34 adult U.S.-based H-A (19 females) and 40 adult C-A (25 females) of similar age and body mass index (BMI, kg/m2). We measured total body volume (TBV), trunk volume (TV), and other body dimensions, including waist and hip circumferences, estimated percentage body fat (%fat), calculated TV/TBV, and waist-to-hip ratio. Results For female cohorts, there were no significant differences in age, weight, height, and 3DPS-measured variables between the two ethnic cohorts. For male cohorts, C-A had greater height (p = 0.014), but there were no significant differences in absolute or proportional volumes or dimensions between the two cohorts. Conclusions Results demonstrate that, in these H-A and C-A cohorts of similar age and BMI, total and regional body volumes and dimensions, as well as their proportions, approximate each other very closely in both sexes; these variables also show similar relationships with %fat in each sex. This is in contradistinction to previous study reports using other measurement techniques. PMID:19885167

Are fetal growth impairment and preterm birth causally related to child attention problems and ADHD? Evidence from a comparison between high-income and middle-income cohorts

PubMed Central

Murray, Elizabeth; Pearson, Rebecca; Fernandes, Michelle; Santos, Iná S; Barros, Fernando C; Victora, Cesar G; Stein, Alan; Matijasevich, Alicia

2016-01-01

Background Cross-cohort comparison is an established method for improving causal inference. This study compared 2 cohorts, 1 from a high-income country and another from a middle-income country, to (1) establish whether birth exposures may play a causal role in the development of childhood attention problems; and (2) identify whether confounding structures play a different role in parent-reported attention difficulties compared with attention deficit hyperactivity disorder (ADHD) diagnoses. Methods Birth exposures included low birth weight (LBW), small-for-gestational age (SGA), small head circumference (HC) and preterm birth (PTB)). Outcomes of interest were attention difficulties (Strengths and Difficulties Questionnaire, SDQ) and ADHD (Development and Well-Being Assessment, DAWBA). Associations between exposures and outcomes were compared between 7-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK (N=6849) and the 2004 Pelotas cohort in Brazil (N=3509). Results For attention difficulties (SDQ), the pattern of association with birth exposures was similar between cohorts: following adjustment, attention difficulties were associated with SGA (OR=1.59, 95% CI 1.20 to 2.19) and small HC (OR=1.64, 95% CI 1.11 to 2.41) in ALSPAC and SGA (OR=1.35, 95% CI 1.04 to 1.75) in Pelotas. For ADHD, however, the pattern of association following adjustment differed markedly between cohorts. In ALSPAC, ADHD was associated with LBW (OR=2.29, 95% CI 1.09 to 4.80) and PTB (OR=2.33, 95% CI 1.23 to 4.42). In the Pelotas cohort, however, ADHD was associated with SGA (OR=1.69, 95% CI 1.02 to 2.82). Conclusions The findings suggest that fetal growth impairment may play a causal role in the development of attention difficulties in childhood, as similar associations were identified across both cohorts. Confounding structures, however, appear to play a greater role in determining whether a child meets the full diagnostic criteria for ADHD. PMID:26767410

The Netherlands Cohort Study – Meat Investigation Cohort; a population-based cohort over-represented with vegetarians, pescetarians and low meat consumers

PubMed Central

2013-01-01

Background Vegetarian diets have been associated with lower risk of chronic disease, but little is known about the health effects of low meat diets and the reliability of self-reported vegetarian status. We aimed to establish an analytical cohort over-represented with vegetarians, pescetarians and 1 day/week meat consumers, and to describe their lifestyle and dietary characteristics. In addition, we were able to compare self-reported vegetarians with vegetarians whose status has been confirmed by their response on the extensive food frequency questionnaire (FFQ). Study methods Embedded within the Netherlands Cohort Study (n = 120,852; including 1150 self-reported vegetarians), the NLCS-Meat Investigation Cohort (NLCS-MIC) was defined by combining all FFQ-confirmed-vegetarians (n = 702), pescetarians (n = 394), and 1 day/week meat consumers (n = 1,396) from the total cohort with a random sample of 2–5 days/week- and 6–7 days/week meat consumers (n = 2,965 and 5,648, respectively). Results Vegetarians, pescetarians, and 1 day/week meat consumers had more favorable dietary intakes (e.g. higher fiber/vegetables) and lifestyle characteristics (e.g. lower smoking rates) compared to regular meat consumers in both sexes. Vegetarians adhered to their diet longer than pescetarians and 1 day/week meat consumers. 75% of vegetarians with a prevalent cancer at baseline had changed to this diet after diagnosis. 50% of self-reported vegetarians reported meat or fish consumption on the FFQ. Although the misclassification that occurred in terms of diet and lifestyle when merely relying on self-reporting was relatively small, the impact on associations with disease risk remains to be studied. Conclusion We established an analytical cohort over-represented with persons at the lower end of the meat consumption spectrum which should facilitate prospective studies of major cancers and causes of death using ≥20.3 years of follow-up. PMID:24289207

Child Sexual Abuse and Persistence of Risky Sexual Behaviors and Negative Sexual Outcomes over Adulthood: Findings from a Birth Cohort

ERIC Educational Resources Information Center

van Roode, Thea; Dickson, Nigel; Herbison, Peter; Paul, Charlotte

2009-01-01

Objectives: To determine the impact of child sexual abuse (CSA) on adult sexual behaviors and outcomes over three age periods. Methods: A longitudinal study of a birth cohort born in Dunedin, New Zealand in 1972/1973 was used. Information on CSA was sought at age 26, and on sexual behaviors and outcomes at ages 21, 26, and 32. Comparisons were…

Implementing the Flipped Classroom in a Veterinary Pre-clinical Science Course: Student Engagement, Performance, and Satisfaction.

PubMed

Dooley, Laura M; Frankland, Sarah; Boller, Elise; Tudor, Elizabeth

2018-01-01

There has been a recent move toward active learning pedagogies in veterinary education, with increasing use of a blended approach that incorporates both online resources and live classroom sessions. In this study, an established veterinary pre-clinical course in introductory animal health was transitioned from a traditional didactic lecture delivery mode to a flipped classroom approach with core content delivered online. This study compared the experiences of two cohorts of students who studied the same course in the different formats in consecutive years. Online learning resources included short video segments and a variety of short problems and activities. Online materials were complemented with weekly small-group case-based learning classes facilitated by academic staff. A mixed methods evaluation strategy was applied using student grades, surveys, and focus groups to compare student academic performance, satisfaction, and engagement between the two cohorts. The flipped classroom cohort achieved significantly higher grades in the written answer section of the final examination. Student satisfaction with learning resources was also higher in this cohort. However, satisfaction with other aspects of the course was largely the same for both cohorts. This study revealed some of the challenges associated with achieving adequate student preparation for class using online resources. The outcomes of this study have implications for veterinary educators considering the design and development of new online learning resources.

Topical Iodine And Fluoride Varnish Combined Is More Effective Than Fluoride Varnish Alone For Protecting Erupting First Permanent Molars: A Retrospective Cohort Study

PubMed Central

Tut, Ohnmar K.; Milgrom, Peter M.

2010-01-01

Objective This communication examines the combined effect of topical PVP-iodine plus fluoride varnish in prevention of tooth decay in erupting first permanent molars in an on-going public health program. Methods The evaluation employed a retrospective cohort design with two groups of children 60–83 months. Cohort 1 (2004–05) received three times per school year topical fluoride varnish, and Cohort 2 (2008–09) received topical application of 10% PVP-iodine followed at each visit with topical fluoride varnish. The children were examined clinically at the beginning and end of the school year. Results The proportion of children with caries-free first permanent molars in Cohort 2 (PVP-iodine plus fluoride varnish) was .883 and was greater than that in Cohort 1 (varnish), which was .785 (Chi-square=1.000E1, df 1, p<.002). Conclusions This evaluation of an on-going dental public health program adds evidence that topical antiseptics applied at the same time as fluoride varnish are more effective than varnish alone. Randomized trials are needed. PMID:20337902

Attention and Off-Topic Speech in the Recounts of Middle-Age and Elderly Adults: A Pilot Investigation

PubMed Central

Wills, Courtney L.; Capilouto, Gilson J.; Wright, Heather Harris

2013-01-01

Purpose The discourse of healthy older adults is commonly described as being lengthy and off-topic and is thought to be associated with a general cognitive decline that accompanies healthy aging. The purpose of this preliminary study was to investigate the overall decline in attention associated with healthy aging and its relationship to instances of off-topic speech (OTS). Method Thirty cognitively healthy adults divided into 5 age cohorts (40–80) completed cognitive measures of attention and several discourse tasks that included recounting personal events. Results Cohorts differed significantly with respect to the measures of attention. However, no significant differences in the incidence of OTS were detected between the cohorts. Attention and the incidence of OTS were not significantly correlated within any of the cohorts. Conclusion No significant differences in the incidence of OTS and its relation to attention measures were found. However, the relationship between age-related declines in attention and increased OTS approached significance, suggesting the need for further study. PMID:23420319

Evaluation of paradoxical TB–associated IRIS with the use of standardized case definitions for resource limited settings

PubMed Central

Eshun-Wilson, Ingrid; Havers, Fiona; Nachega, Jean B; Prozesky, Hans W; Taljaard, Jantjie J; Zeier, Michele D; Cotton, Mark; Simon, Gary; Soentjens, Patrick

2011-01-01

Objective Standardized case definitions have recently been proposed by the International Network for the Study of HIV-associated IRIS (INSHI) for use in resource-limited settings. We evaluated paradoxical TB-associated IRIS in a large cohort from a TB endemic setting with the use of these case definitions. Design A retrospective cohort analysis. Methods We reviewed records from 1250 South African patients who initiated anti-retroviral therapy (ART) over a five-year period. Results 333 (27%) of the patients in the cohort had prevalent TB at the initiation of ART. Of 54 possible paradoxical TB-associated IRIS cases, 35 fulfilled the INSHI case definitions (11% of TB cases). Conclusions INSHI standardised case definitions were used successfully in identifying paradoxical TB-associated IRIS in this cohort and resulted in a similar proportion of TB IRIS cases (11%) as that reported in previous studies from resource-limited settings (8-13%). This case definition should be evaluated prospectively. PMID:20160249

Self-Reported Functional Status among the Old-Old: A Comparison of Two Israeli Cohorts

PubMed Central

Litwin, Howard; Shrira, Amit; Shmotkin, Dov

2012-01-01

OBJECTIVES To examine differences in functional status among two successive cohorts. METHODS The study was a comparative analysis of Jewish respondents aged 75–94 from two nationwide random samples: the Cross-Sectional and Longitudinal Aging Study (1989–1992; N =1200) and the Survey of Health, Ageing, and Retirement in Europe (2005–2006; N =379). Self-reported functional limitation and disability were compared by means of logistic regressions and MANCOVA, controlling for age, gender, origin, education, marital status, income, self-rated health, and home care receipt. RESULTS Reported functional limitation decreased in the later cohort (SHARE-Israel), but ADL- and IADL-disability increased. Receipt of home care moderated these effects. ADL- and IADL-disability increased among home-care-receiving respondents in the later cohort whereas functional limitation decreased among respondents not in receipt of home care. DISCUSSION The findings suggest that different measures used to assess the disablement process capture different aspects, and that contextual factors influence how older people rate their own functional capacity. PMID:22422761

How accurately does high tibial osteotomy correct the mechanical axis of an arthritic varus knee? A systematic review.

PubMed

Van den Bempt, Maxim; Van Genechten, Wouter; Claes, Toon; Claes, Steven

2016-12-01

The aim of this study was to give an overview of the accuracy of coronal limb alignment correction after high tibial osteotomy (HTO) for the arthritic varus knee by performing a systematic review of the literature. The databases PubMed, MEDLINE and Cochrane Library were screened for relevant articles. Only prospective clinical studies with the accuracy of alignment correction by performing HTO as primary or secondary objective were included. Fifteen studies were included in this systematic review and were subdivided in 23 cohorts. A total of 966 procedures were considered. Nine cohorts used computer navigation during HTO and the other 14 cohorts used a conventional method. In seven computer navigation cohorts, at least 75% of the study population fell into the accepted "range of accuracy" (AR) as proposed by the different studies, but only six out of 14 conventional cohorts reached this percentage. Four out of eight conventional cohorts that provided data on under- and overcorrection, had a tendency to undercorrection. The accuracy of coronal alignment corrections using conventional HTO falls short. The number of procedures outside the proposed AR is surprising and exposes a critical concern for modern HTO. Computer navigation might improve the accuracy of correction, but its use is not widespread among orthopedic surgeons. Although HTO procedures have been shown to be successful in the treatment of unicompartmental knee arthritis when performed accurately, the results of this review stress the importance of ongoing efforts in order to improve correction accuracy in modern HTO. Copyright © 2016 Elsevier B.V. All rights reserved.

Responsiveness-informed multiple imputation and inverse probability-weighting in cohort studies with missing data that are non-monotone or not missing at random.

PubMed

Doidge, James C

2018-02-01

Population-based cohort studies are invaluable to health research because of the breadth of data collection over time, and the representativeness of their samples. However, they are especially prone to missing data, which can compromise the validity of analyses when data are not missing at random. Having many waves of data collection presents opportunity for participants' responsiveness to be observed over time, which may be informative about missing data mechanisms and thus useful as an auxiliary variable. Modern approaches to handling missing data such as multiple imputation and maximum likelihood can be difficult to implement with the large numbers of auxiliary variables and large amounts of non-monotone missing data that occur in cohort studies. Inverse probability-weighting can be easier to implement but conventional wisdom has stated that it cannot be applied to non-monotone missing data. This paper describes two methods of applying inverse probability-weighting to non-monotone missing data, and explores the potential value of including measures of responsiveness in either inverse probability-weighting or multiple imputation. Simulation studies are used to compare methods and demonstrate that responsiveness in longitudinal studies can be used to mitigate bias induced by missing data, even when data are not missing at random.

Attrition bias in a U.S. Internet survey of alcohol use among college freshmen.

PubMed

McCoy, Thomas P; Ip, Edward H; Blocker, Jill N; Champion, Heather; Rhodes, Scott D; Wagoner, Kimberly G; Mitra, Ananda; Wolfson, Mark

2009-07-01

Attrition bias is an important issue in survey research on alcohol, tobacco, and other drug use. The issue is even more salient for Internet studies, because these studies often have higher rates of attrition than face-to-face or telephone surveys, and there is limited research examining the issue in the field of drug usage, specifically for college underclassmen. This study assessed whether measures of high-risk drinking and alcohol-related consequences were related to attrition groups ("stayers" or "leavers") in a cohort of college freshmen. Data were collected in 2003 and 2004 from 2,144 first-year college students at 10 universities in the southeastern United States. Demographics, indicators of high-risk drinking, and alcohol-related consequences were compared between cohort stayers and leavers in statistical analyses using two methods. Analyses indicated that cohort leavers reported significantly higher levels of high-risk drinking (past-30-day heavy episodic drinking, weekly drunkenness) and past-30-day smoking but not significantly increased alcohol-related consequences. The directionality of bias was modestly consistent across outcomes and comparison methods. The current study's findings suggest that intervention efforts to reduce smoking or high-risk drinking need to consider attrition bias during study follow-up or account for it in analyses.

Regression to the Mean and Changes in Risk Behavior following Study Enrollment in a Cohort of US Women at Risk for HIV

PubMed Central

Hughes, James P.; Haley, Danielle F.; Frew, Paula M.; Golin, Carol E.; Adimora, Adaora A; Kuo, Irene; Justman, Jessica; Soto-Torres, Lydia; Wang, Jing; Hodder, Sally

2015-01-01

Purpose Reductions in risk behaviors are common following enrollment in HIV prevention studies. We develop methods to quantify the proportion of change in risk behaviors that can be attributed to regression to the mean versus study participation and other factors. Methods A novel model that incorporates both regression to the mean and study participation effects is developed for binary measures. The model is used to estimate the proportion of change in the prevalence of “unprotected sex in the past 6 months” that can be attributed to study participation versus regression to the mean in a longitudinal cohort of women at risk for HIV infection who were recruited from ten US communities with high rates of HIV and poverty. HIV risk behaviors were evaluated using audio computer-assisted self-interviews at baseline and every 6 months for up to 12 months. Results The prevalence of “unprotected sex in the past 6 months” declined from 96% at baseline to 77% at 12 months. However, this change could be almost completely explained by regression to the mean. Conclusions Analyses that examine changes over time in cohorts selected for high or low risk behaviors should account for regression to the mean effects. PMID:25883065

Smoking Trends among U.S. Latinos, 1998–2013: The Impact of Immigrant Arrival Cohort

PubMed Central

Bostean, Georgiana; Ro, Annie; Fleischer, Nancy L.

2017-01-01

Few studies examine nativity disparities in smoking in the U.S., thus a major gap remains in understanding whether immigrant Latinos’ smoking prevalence is stable, converging, or diverging, compared with U.S.-born Latinos. This study aimed to disentangle the roles of period changes, duration of U.S. residence, and immigrant arrival cohort in explaining the gap in smoking prevalence between foreign-born and U.S.-born Latinos. Using repeated cross-sectional data spanning 1998–2013 (U.S. National Health Interview Survey), regressions predicted current smoking among foreign-born and U.S.-born Latino men and women (n = 12,492). We contrasted findings from conventional regression analyses that simply include period and duration of residence effects, to two methods of assessing arrival cohort effects: the first accounted for baseline differences in smoking among arrival cohorts, while the second examined smoking probabilities by tracking foreign-born arrival cohorts as they increase their duration of U.S. residence. Findings showed that Latino immigrants maintained lower prevalence of current smoking compared with U.S.-born Latinos over the period 1998–2013, and that longer duration of U.S. residence is associated with lower odds of smoking among men. Two findings are particularly novel: (1) accounting for immigrant arrival cohort dampens the overall protective effect of duration of residence among men; and (2) the earliest arrival cohort of Latino immigrant men experienced the steepest decline in smoking over duration of U.S. residence. Results have methodological and theoretical implications for smoking studies and the Latino mortality paradox. PMID:28257125

Time from HIV seroconversion to death: a collaborative analysis of eight studies in six low and middle-income countries before highly active antiretroviral therapy

PubMed Central

Todd, Jim; Glynn, Judith R.; Marston, Milly; Lutalo, Tom; Biraro, Sam; Mwita, Wambura; Suriyanon, Vinai; Rangsin, Ram; Nelson, Kenrad E.; Sonnenberg, Pam; Fitzgerald, Dan; Karita, Etienne; Żaba, Basia

2018-01-01

Objectives To estimate survival patterns after HIV infection in adults in low and middle-income countries. Design An analysis of pooled data from eight different studies in six countries. Methods HIV seroconverters were included from eight studies (three population-based, two occupational, and three clinic cohorts) if they were at least 15 years of age, and had no more than 4 years between the last HIV-negative and subsequent HIV-positive test. Four strata were defined: East African cohorts; South African miners cohort; Thai cohorts; Haitian clinic cohort. Kaplan–Meier functions were used to estimate survival patterns, and Weibull distributions were used to model and extend survival estimates. Analyses examined the effect of site, age, and sex on survival. Results From 3823 eligible seroconverters, 1079 deaths were observed in 19 671 person-years of follow-up. Survival times varied by age and by study site. Adjusting to age 25–29 years at seroconversion, the median survival was longer in South African miners: 11.6 years [95% confidence interval (CI) 9.8–13.7] and East African cohorts: 11.1 years (95% CI 8.7–14.2) than in Haiti: 8.3 years (95% CI 3.2–21.4) and Thailand: 7.5 years (95% CI 5.4–10.4). Survival was similar for men and women, after adjustment for age at seroconversion and site. Conclusion Without antiretroviral therapy, overall survival after HIV infection in African cohorts was similar to survival in high-income countries, with a similar pattern of faster progression at older ages at seroconversion. Survival appears to be significantly worse in Thailand where other, unmeasured factors may affect progression. PMID:18032940

Genome-Wide Association Study of Suicide Attempts in Mood Disorder Patients

PubMed Central

Perlis, Roy H.; Huang, Jie; Purcell, Shaun; Fava, Maurizio; Rush, A. John; Sullivan, Patrick F.; Hamilton, Steven P.; McMahon, Francis J.; Schulze, Thomas; Potash, James B.; Zandi, Peter P.; Willour, Virginia L.; Penninx, Brenda W.; Boomsma, Dorret I.; Vogelzangs, Nicole; Middeldorp, Christel M.; Rietschel, Marcella; Nöthen, Markus; Cichon, Sven; Gurling, Hugh; Bass, Nick; McQuillin, Andrew; Hamshere, Marian; Craddock, Nick; Sklar, Pamela; Smoller, Jordan W.

2013-01-01

Objective Family and twin studies suggest that liability for suicide attempts is heritable and distinct from mood disorder susceptibility. The authors therefore examined the association between common genomewide variation and lifetime suicide attempts. Method The authors analyzed data on lifetime suicide attempts from genomewide association studies of bipolar I and II disorder as well as major depressive disorder. Bipolar disorder subjects were drawn from the Systematic Treatment Enhancement Program for Bipolar Disorder cohort, the Wellcome Trust Case Control Consortium bipolar cohort, and the University College London cohort. Replication was pursued in the NIMH Genetic Association Information Network bipolar disorder project and a German clinical cohort. Depression subjects were drawn from the Sequential Treatment Alternatives to Relieve Depression cohort, with replication in the Netherlands Study of Depression and Anxiety/Netherlands Twin Register depression cohort. Results Strongest evidence of association for suicide attempt in bipolar disorder was observed in a region without identified genes (rs1466846); five loci also showed suggestive evidence of association. In major depression, strongest evidence of association was observed for a single nucleotide polymorphism in ABI3BP, with six loci also showing suggestive association. Replication cohorts did not provide further support for these loci. However, meta-analysis incorporating approximately 8,700 mood disorder subjects identified four additional regions that met the threshold for suggestive association, including the locus containing the gene coding for protein kinase C-epsilon, previously implicated in models of mood and anxiety. Conclusions The results suggest that inherited risk for suicide among mood disorder patients is unlikely to be the result of individual common variants of large effect. They nonetheless provide suggestive evidence for multiple loci, which merit further investigation. PMID:21041247

The protocol of a population-based prospective cohort study in southwest of Iran to analyze common non-communicable diseases: Shahrekord cohort study.

PubMed

Khaledifar, Arsalan; Hashemzadeh, Morteza; Solati, Kamal; Poustchi, Hosseion; Bollati, Valentina; Ahmadi, Ali; Kheiri, Soleiman; Samani, Keihan Ghatreh; Banitalebi, Mehdi; Sedehi, Morteza; Malekzadeh, Reza

2018-05-25

Prospective cohort studies are considered ideal choices to study multiple outcomes and risk factors for Non-communicable diseases (NCDs). Our aim is to set-up the protocol and analyze risk factors, incidence rates, prevalence, trends, and the models of environmental and genetic determinants of NCDs and their outcomes as well as interaction among such determinants. Shahrekord cohort study (SCS) that is a population-based prospective, study on a cohort consisting of people aged 35-70 years started in November 2015 in Iran. The sample size of the original cohort is at least 10,000 people. Annual follow-ups (200,000 person-year) of the cohort were designed to be conducted up to 2036. Exposures (a detailed demographic, socioeconomic, general health, quality of life, physical activity, anthropometric indexes, stress, health literacy, social capital, nutrition and eating habits, lifestyle, occupational history, living place, blindness, deafness, electrocardiography, lung capacities, blood pressure, sleep, smoking and alcohol, contact to animals, physical examinations and medical history, dental health, used drugs and supplements, glucose and lipid profiles) were measured by relevant standard methods and questionnaires. Incidence of common NCDs (cardiovascular diseases, cancer, gastrointestinal, respiratory, renal, hepatic, accidents, injury and neurological diseases), trend of risk factors, hospitalization, disability, and death were considered the outcomes of the cohort. The definition of disease was determined based on the International Classification of Diseases 10th version (ICD-10). Routine hematologic and biochemical tests were conducted and an all-inclusive biobank (blood, hair, nail, and urine specimens) of the cohort was stored for future studies. All steps of data collection and examinations are directly monitored by the quality control team. The SCS is a unique study conducted in southwest of Iran that is a notable work given the climate conditions and ethnicity population (especially in Bakhtiari) of this region. By providing high quality the protocol and introduce it, the SCS can serve as a solid foundation for management and researchers in southwest of Iran. The SCS provides prerequisites for collaboration and regional, national, and international studies on NCDs. Data are available at the modeling in health research center, Shahrekord University of Medical Sciences, Shahrekord, Iran, for any collaboration.

Sample size for positive and negative predictive value in diagnostic research using case–control designs

PubMed Central

Steinberg, David M.; Fine, Jason; Chappell, Rick

2009-01-01

Important properties of diagnostic methods are their sensitivity, specificity, and positive and negative predictive values (PPV and NPV). These methods are typically assessed via case–control samples, which include one cohort of cases known to have the disease and a second control cohort of disease-free subjects. Such studies give direct estimates of sensitivity and specificity but only indirect estimates of PPV and NPV, which also depend on the disease prevalence in the tested population. The motivating example arises in assay testing, where usage is contemplated in populations with known prevalences. Further instances include biomarker development, where subjects are selected from a population with known prevalence and assessment of PPV and NPV is crucial, and the assessment of diagnostic imaging procedures for rare diseases, where case–control studies may be the only feasible designs. We develop formulas for optimal allocation of the sample between the case and control cohorts and for computing sample size when the goal of the study is to prove that the test procedure exceeds pre-stated bounds for PPV and/or NPV. Surprisingly, the optimal sampling schemes for many purposes are highly unbalanced, even when information is desired on both PPV and NPV. PMID:18556677

Cohort Graduation Rate: Policy and Technical Manual. 2016-17 Graduation Rates Based on Students First Entering High School during the 2012-13 and 2013-14 School Years

ERIC Educational Resources Information Center

Oregon Department of Education, 2017

2017-01-01

High School graduation rates are key indicators of accountability for high schools and school districts in Oregon. Beginning with the 2008-09 school year, the Oregon Department of Education (ODE) implemented the cohort method of calculating graduation rates. The cohort method identifies the year the student entered high school for the first time…

Policy and Persistence: An Exploratory Mixed Methods Case Study of "Last Mile" Students at Portland State University

ERIC Educational Resources Information Center

Wubbold, Joseph Mark

2012-01-01

In an extension of educational attainment research, this exploratory mixed- methods case study examines the influence of institutional policies on the behavior of five cohorts (n = 925) of traditional first time, full time (FTFT) freshmen--called "Last Mile" students--at one urban research university located in the Pacific Northwest.…

Validation of exposure assessment and assessment of recruitment methods for a prospective cohort study of mobile phone users (COSMOS) in Finland: a pilot study

PubMed Central

2011-01-01

Background The aim of the study was to evaluate the agreement between self-reported and operator-derived estimates of call time based on a three-month monitoring period, as well as the consistency of mobile phone use over time. Alternative approaches to improve participation in a cohort study of mobile phone users were also compared. Methods A total of 5,400 subjects were identified from network operators' subscriber databases for recruitment to the pilot study. Operator and questionnaire data were used to quantify mobile phone use. Operator data were available for a subset of the subjects for a three-month period in three consecutive years. We also evaluated the effect of the length of the questionnaire and one- or two-phase recruitment on participation. Results The average response rate for both questionnaires and recruitment procedures was 12%. The response rate was not affected by the length of the questionnaire or the recruitment method. Operator data were available for 83% of the participants for 2007, the first study year. The agreement between self-reported and operator-derived call times decreased with the level of use among intermediate and heavy mobile phone users. During 2007-2009, mobile phone use increased fairly constantly over time. Conclusions The agreement between self-reported mobile phone use and operator databases was moderate and overestimation of the call time by participants was common. A prospective cohort study would be feasible in Finland, although the potentially low participation rate would increase the resources required for recruitment. PMID:21385407

Development and validation of a predictive model for excessive postpartum blood loss: A retrospective, cohort study.

PubMed

Rubio-Álvarez, Ana; Molina-Alarcón, Milagros; Arias-Arias, Ángel; Hernández-Martínez, Antonio

2018-03-01

postpartum haemorrhage is one of the leading causes of maternal morbidity and mortality worldwide. Despite the use of uterotonics agents as preventive measure, it remains a challenge to identify those women who are at increased risk of postpartum bleeding. to develop and to validate a predictive model to assess the risk of excessive bleeding in women with vaginal birth. retrospective cohorts study. "Mancha-Centro Hospital" (Spain). the elaboration of the predictive model was based on a derivation cohort consisting of 2336 women between 2009 and 2011. For validation purposes, a prospective cohort of 953 women between 2013 and 2014 were employed. Women with antenatal fetal demise, multiple pregnancies and gestations under 35 weeks were excluded METHODS: we used a multivariate analysis with binary logistic regression, Ridge Regression and areas under the Receiver Operating Characteristic curves to determine the predictive ability of the proposed model. there was 197 (8.43%) women with excessive bleeding in the derivation cohort and 63 (6.61%) women in the validation cohort. Predictive factors in the final model were: maternal age, primiparity, duration of the first and second stages of labour, neonatal birth weight and antepartum haemoglobin levels. Accordingly, the predictive ability of this model in the derivation cohort was 0.90 (95% CI: 0.85-0.93), while it remained 0.83 (95% CI: 0.74-0.92) in the validation cohort. this predictive model is proved to have an excellent predictive ability in the derivation cohort, and its validation in a latter population equally shows a good ability for prediction. This model can be employed to identify women with a higher risk of postpartum haemorrhage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased pathological complete response rate after a long-term neoadjuvant letrozole treatment in postmenopausal oestrogen and/or progesterone receptor-positive breast cancer

PubMed Central

Allevi, G; Strina, C; Andreis, D; Zanoni, V; Bazzola, L; Bonardi, S; Foroni, C; Milani, M; Cappelletti, M R; Gussago, F; Aguggini, S; Giardini, R; Martinotti, M; Fox, S B; Harris, A L; Bottini, A; Berruti, A; Generali, D

2013-01-01

Background: The objective of this study was to determine the optimal scheduling of 2.5 mg daily letrozole in neoadjuvant breast cancer patients to obtain pathological complete response (pathCR) and assess Ki-67 expression as an early predictor of response. Patients and methods: This single institution study comprised 120 oestrogen receptor (ER)-positive postmenopausal women with primary breast cancer (clinical stage ⩾T2, N0–1), from three sequential cohorts (cohort A of 40, cohort B of 40 and cohort C of 40 patients, respectively) based on different duration of the neoadjuvant letrozole. Biological markers such as ER, progesterone receptor, HER2 and Ki-67 expression were tested at diagnosis and at definitive surgery. Results: A total of 89 patients (75.4%) achieved an objective response with 44 (37.3%) clinical CRs and 45 (38.1%) partial responses. The clinical CRs were significantly observed in cohort C (23 out of 40 patients, 57.5%) and B (16 out of 38 patients, 42.1%) compared with cohort A (5 out of 40 patients, 12.5%) (P-value for trend <0.001). Letrozole induced a similar significant reduction in Ki-67 index after treatment in all cohorts. The pathCR rate was significantly more frequent in cohort C (7 out of 40 patients, 17.5%) than in cohort A (1 out of 40 patients, 2.5%) and B (2 out of 40 patients, 5.0%) (P-value for trend <0.04). Conclusion: One-year neoadjuvant letrozole therapy leads to a higher pathCR rate and may be the optimal length of drug exposure. PMID:23579222

Design of an Air Pollution Monitoring Campaign in Beijing for Application to Cohort Health Studies.

PubMed

Vedal, Sverre; Han, Bin; Xu, Jia; Szpiro, Adam; Bai, Zhipeng

2017-12-15

No cohort studies in China on the health effects of long-term air pollution exposure have employed exposure estimates at the fine spatial scales desirable for cohort studies with individual-level health outcome data. Here we assess an array of modern air pollution exposure estimation approaches for assigning within-city exposure estimates in Beijing for individual pollutants and pollutant sources to individual members of a cohort. Issues considered in selecting specific monitoring data or new monitoring campaigns include: needed spatial resolution, exposure measurement error and its impact on health effect estimates, spatial alignment and compatibility with the cohort, and feasibility and expense. Sources of existing data largely include administrative monitoring data, predictions from air dispersion or chemical transport models and remote sensing (specifically satellite) data. New air monitoring campaigns include additional fixed site monitoring, snapshot monitoring, passive badge or micro-sensor saturation monitoring and mobile monitoring, as well as combinations of these. Each of these has relative advantages and disadvantages. It is concluded that a campaign in Beijing that at least includes a mobile monitoring component, when coupled with currently available spatio-temporal modeling methods, should be strongly considered. Such a campaign is economical and capable of providing the desired fine-scale spatial resolution for pollutants and sources.

Design of an Air Pollution Monitoring Campaign in Beijing for Application to Cohort Health Studies

PubMed Central

Vedal, Sverre; Han, Bin; Szpiro, Adam; Bai, Zhipeng

2017-01-01

No cohort studies in China on the health effects of long-term air pollution exposure have employed exposure estimates at the fine spatial scales desirable for cohort studies with individual-level health outcome data. Here we assess an array of modern air pollution exposure estimation approaches for assigning within-city exposure estimates in Beijing for individual pollutants and pollutant sources to individual members of a cohort. Issues considered in selecting specific monitoring data or new monitoring campaigns include: needed spatial resolution, exposure measurement error and its impact on health effect estimates, spatial alignment and compatibility with the cohort, and feasibility and expense. Sources of existing data largely include administrative monitoring data, predictions from air dispersion or chemical transport models and remote sensing (specifically satellite) data. New air monitoring campaigns include additional fixed site monitoring, snapshot monitoring, passive badge or micro-sensor saturation monitoring and mobile monitoring, as well as combinations of these. Each of these has relative advantages and disadvantages. It is concluded that a campaign in Beijing that at least includes a mobile monitoring component, when coupled with currently available spatio-temporal modeling methods, should be strongly considered. Such a campaign is economical and capable of providing the desired fine-scale spatial resolution for pollutants and sources. PMID:29244738

Causes of death and expected years of life lost among treated opioid-dependent individuals in the United States and Taiwan

PubMed Central

Chang, Kun-Chia; Wang, Jung-Der; Saxon, Andrew; Matthews, Abigail G.; Woody, George; Hser, Yih-Ing

2017-01-01

Aims This study compared the cause-specific standardized mortality ratios (SMRs) and expected years of life lost (EYLL) among opioid-dependent individuals in the United States and Taiwan. Methods Survival data came from two cohorts followed until 2014: The U.S. data were based on a randomized trial of 1,267 opioid-dependent participants enrolled between 2006 and 2009; the Taiwan data were from a study of 983 individuals that began in 2006, when opioid agonist treatment (OAT) was implemented in Taiwan. SMRs were calculated for each national cohort and compared. Kaplan-Meier estimation was performed on the survival data, then lifespans were extrapolated to 70 years (840 months) to estimate life expectancy using a semi-parametric method. EYLLs for both cohorts were estimated by subtracting their life expectancies from the age- and gender-matched referents within the general population of their respective country. Results Compared with age- and gender- matched referents, the SMRs were 3.2 for the U.S. sample and 7.8 for the Taiwan sample; the EYLLs were 7.7 and 16.4 years, respectively. Half of decedents died of unnatural causes in both cohorts; overdose deaths predominated in the U.S. and suicide in Taiwan. Conclusions Our study identified differences by country in EYLL and causes of deaths. These findings suggest that intervention strategies to reduce mortality risk by overdose (particularly in the U.S.) and suicide (particularly in Taiwan) are urgently needed in these countries. PMID:28160734

Robust best linear estimator for Cox regression with instrumental variables in whole cohort and surrogates with additive measurement error in calibration sample.

PubMed

Wang, Ching-Yun; Song, Xiao

2016-11-01

Biomedical researchers are often interested in estimating the effect of an environmental exposure in relation to a chronic disease endpoint. However, the exposure variable of interest may be measured with errors. In a subset of the whole cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies an additive measurement error model, but it may not have repeated measurements. The subset in which the surrogate variables are available is called a calibration sample. In addition to the surrogate variables that are available among the subjects in the calibration sample, we consider the situation when there is an instrumental variable available for all study subjects. An instrumental variable is correlated with the unobserved true exposure variable, and hence can be useful in the estimation of the regression coefficients. In this paper, we propose a nonparametric method for Cox regression using the observed data from the whole cohort. The nonparametric estimator is the best linear combination of a nonparametric correction estimator from the calibration sample and the difference of the naive estimators from the calibration sample and the whole cohort. The asymptotic distribution is derived, and the finite sample performance of the proposed estimator is examined via intensive simulation studies. The methods are applied to the Nutritional Biomarkers Study of the Women's Health Initiative. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phase II study of monthly pasireotide LAR (SOM230C) for recurrent or progressive meningioma

PubMed Central

Norden, Andrew D.; Ligon, Keith L.; Hammond, Samantha N.; Muzikansky, Alona; Reardon, David A.; Kaley, Thomas J.; Batchelor, Tracy T.; Plotkin, Scott R.; Raizer, Jeffrey J.; Wong, Eric T.; Drappatz, Jan; Lesser, Glenn J.; Haidar, Sam; Beroukhim, Rameen; Lee, Eudocia Q.; Doherty, Lisa; Lafrankie, Debra; Gaffey, Sarah C.; Gerard, Mary; Smith, Katrina H.; McCluskey, Christine; Phuphanich, Surasak

2015-01-01

Objective: A subset of meningiomas recur after surgery and radiation therapy, but no medical therapy for recurrent meningioma has proven effective. Methods: Pasireotide LAR is a long-acting somatostatin analog that may inhibit meningioma growth. This was a phase II trial in patients with histologically confirmed recurrent or progressive meningioma designed to evaluate whether pasireotide LAR prolongs progression-free survival at 6 months (PFS6). Patients were stratified by histology (atypical [World Health Organization grade 2] and malignant [grade 3] meningiomas in cohort A and benign [grade 3] in cohort B). Results: Eighteen patients were accrued in cohort A and 16 in cohort B. Cohort A had median age 59 years, median Karnofsky performance status 80, 17 (94%) had previous radiation therapy, and 11 (61%) showed high octreotide uptake. Cohort B had median age 52 years, median Karnofsky performance status 90, 11 (69%) had previous radiation therapy, and 12 (75%) showed high octreotide uptake. There were no radiographic responses to pasireotide LAR therapy in either cohort. Twelve patients (67%) in cohort A and 13 (81%) in cohort B achieved stable disease. In cohort A, PFS6 was 17% and median PFS 15 weeks (95% confidence interval: 8–20). In cohort B, PFS6 was 50% and median PFS 26 weeks (12–43). Treatment was well tolerated. Octreotide uptake and insulin-like growth factor–1 levels did not predict outcome. Expression of somatostatin receptor 3 predicted favorable PFS and overall survival. Conclusions: Pasireotide LAR has limited activity in recurrent meningiomas. The finding that somatostatin receptor 3 is associated with favorable outcomes warrants further investigation. Classification of evidence: This study provides Class IV evidence that in patients with recurrent or progressive meningioma, pasireotide LAR does not significantly increase the proportion of patients with PFS at 6 months. PMID:25527270

Secular trends: a ten-year comparison of the amount and type of physical activity and inactivity of random samples of adolescents in the Czech Republic

PubMed Central

2011-01-01

Background An optimal level of physical activity (PA) in adolescence influences the level of PA in adulthood. Although PA declines with age have been demonstrated repeatedly, few studies have been carried out on secular trends. The present study assessed levels, types and secular trends of PA and sedentary behaviour of a sample of adolescents in the Czech Republic. Methods The study comprised two cross-sectional cohorts of adolescents ten years apart. The analysis compared data collected through a week-long monitoring of adolescents' PA in 1998-2000 and 2008-2010. Adolescents wore either Yamax SW-701 or Omron HJ-105 pedometer continuously for 7 days (at least 10 hours per day) excluding sleeping, hygiene and bathing. They also recorded their number of steps per day, the type and duration of PA and sedentary behaviour (in minutes) on record sheets. In total, 902 adolescents (410 boys; 492 girls) aged 14-18 were eligible for analysis. Results Overweight and obesity in Czech adolescents participating in this study increased from 5.5% (older cohort, 1998-2000) to 10.4% (younger cohort, 2008-2010). There were no inter-cohort significant changes in the total amount of sedentary behaviour in boys. However in girls, on weekdays, there was a significant increase in the total duration of sedentary behaviour of the younger cohort (2008-2010) compared with the older one (1998-2000). Studying and screen time (television and computer) were among the main sedentary behaviours in Czech adolescents. The types of sedentary behaviour also changed: watching TV (1998-2000) was replaced by time spent on computers (2008-2010). The Czech health-related criterion (achieving 11,000 steps per day) decreased only in boys from 68% (1998-2000) to 55% (2008-2010). Across both genders, 55%-75% of Czech adolescents met the health-related criterion of recommended steps per day, however less participants in the younger cohort (2008-2010) met this criterion than in the older cohort (1998-2000) ten years ago. Adolescents' PA levels for the monitored periods of 1998-2000 and 2008-2010 suggest a secular decrease in the weekly number of steps achieved by adolescent boys and girls. Conclusion In the younger cohort (2008-2010), every tenth adolescent was either overweight or obese; roughly twice the rate when compared to the older cohort (1998-2000). Sedentary behaviour seems relatively stable across the two cohorts as the increased time that the younger cohort (2008-2010) spent on computers is compensated with an equally decreased time spent watching TV or studying. Across both cohorts about half to three quarters of the adolescents met the health-related criterion for achieved number of steps. The findings show a secular decrease in PA amongst adolescents. The significant interaction effects (cohort × age; and cohort × gender) that this study found suggested that secular trends in PA differ by age and gender. PMID:21943194

Multi-Cohort Stand Structural Classification: Ground- and LiDAR-based Approaches for Boreal Mixedwood and Black Spruce Forest Types of Northeastern Ontario

NASA Astrophysics Data System (ADS)

Kuttner, Benjamin George

Natural fire return intervals are relatively long in eastern Canadian boreal forests and often allow for the development of stands with multiple, successive cohorts of trees. Multi-cohort forest management (MCM) provides a strategy to maintain such multi-cohort stands that focuses on three broad phases of increasingly complex, post-fire stand development, termed "cohorts", and recommends different silvicultural approaches be applied to emulate different cohort types. Previous research on structural cohort typing has relied upon primarily subjective classification methods; in this thesis, I develop more comprehensive and objective methods for three common boreal mixedwood and black spruce forest types in northeastern Ontario. Additionally, I examine relationships between cohort types and stand age, productivity, and disturbance history and the utility of airborne LiDAR to retrieve ground-based classifications and to extend structural cohort typing from plot- to stand-levels. In both mixedwood and black spruce forest types, stand age and age-related deadwood features varied systematically with cohort classes in support of an age-based interpretation of increasing cohort complexity. However, correlations of stand age with cohort classes were surprisingly weak. Differences in site productivity had a significant effect on the accrual of increasingly complex multi-cohort stand structure in both forest types, especially in black spruce stands. The effects of past harvesting in predictive models of class membership were only significant when considered in isolation of age. As an age-emulation strategy, the three cohort model appeared to be poorly suited to black spruce forests where the accrual of structural complexity appeared to be more a function of site productivity than age. Airborne LiDAR data appear to be particularly useful in recovering plot-based cohort types and extending them to the stand-level. The main gradients of structural variability detected using LiDAR were similar between boreal mixedwood and black spruce forest types; the best LiDAR-based models of cohort type relied upon combinations of tree size, size heterogeneity, and tree density related variables. The methods described here to measure, classify, and predict cohort-related structural complexity assist in translating the conceptual three cohort model to a more precise, measurement-based management system. In addition, the approaches presented here to measure and classify stand structural complexity promise to significantly enhance the detail of structural information in operational forest inventories in support of a wide array of forest management and conservation applications.

Work-family life courses and BMI trajectories in three British birth cohorts

PubMed Central

Lacey, R E; Sacker, A; Bell, S; Kumari, M; Worts, D; McDonough, P; Kuh, D; McMunn, A

2017-01-01

BACKGROUND/OBJECTIVES: Combining work and family responsibilities has previously been associated with improved health in mid-life, yet little is known about how these associations change over time (both biographical and historical) and whether this extends to body mass index (BMI) trajectories for British men and women. The purpose of this study was to investigate relationships between work-family life courses and BMI trajectories across adulthood (16–42 years) for men and women in three British birth cohorts. SUBJECTS/METHODS: Multiply imputed data from three nationally representative British birth cohorts were used—the MRC National Survey of Health and Development (NSHD; 1946 birth cohort, n=3012), the National Child Development Study (NCDS; 1958 birth cohort, n=9614) and the British Cohort Study (BCS; 1970 birth cohort, n=8140). A typology of work-family life course types was developed using multi-channel sequence analysis, linking annual information on work, partnerships and parenthood from 16 to 42 years. Work-family life courses were related to BMI trajectories using multi-level growth models. Analyses adjusted for indicators of prior health, birthweight, child BMI, educational attainment and socioeconomic position across the life course, and were stratified by gender and cohort. RESULTS: Work-family life courses characterised by earlier transitions to parenthood and weaker long-term links to employment were associated with greater increases in BMI across adulthood. Some of these differences, particularly for work-family groups, which are becoming increasingly non-normative, became more pronounced across cohorts (for example, increases in BMI between 16 and 42 years in long-term homemaking women: NSHD: 4.35 kg m–2, 95% confidence interval (CI): 3.44, 5.26; NCDS: 5.53 kg m–2, 95% CI: 5.18, 5.88; BCS: 6.69 kg m–2, 95% CI: 6.36, 7.02). CONCLUSIONS: Becoming a parent earlier and weaker long-term ties to employment are associated with greater increases in BMI across adulthood in British men and women. PMID:27811951

A 2-Stage Genome-Wide Association Study to Identify Single Nucleotide Polymorphisms Associated With Development of Erectile Dysfunction Following Radiation Therapy for Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerns, Sarah L.; Departments of Pathology and Genetics, Albert Einstein College of Medicine, Bronx, New York; Stock, Richard

2013-01-01

Purpose: To identify single nucleotide polymorphisms (SNPs) associated with development of erectile dysfunction (ED) among prostate cancer patients treated with radiation therapy. Methods and Materials: A 2-stage genome-wide association study was performed. Patients were split randomly into a stage I discovery cohort (132 cases, 103 controls) and a stage II replication cohort (128 cases, 102 controls). The discovery cohort was genotyped using Affymetrix 6.0 genome-wide arrays. The 940 top ranking SNPs selected from the discovery cohort were genotyped in the replication cohort using Illumina iSelect custom SNP arrays. Results: Twelve SNPs identified in the discovery cohort and validated in themore » replication cohort were associated with development of ED following radiation therapy (Fisher combined P values 2.1 Multiplication-Sign 10{sup -5} to 6.2 Multiplication-Sign 10{sup -4}). Notably, these 12 SNPs lie in or near genes involved in erectile function or other normal cellular functions (adhesion and signaling) rather than DNA damage repair. In a multivariable model including nongenetic risk factors, the odds ratios for these SNPs ranged from 1.6 to 5.6 in the pooled cohort. There was a striking relationship between the cumulative number of SNP risk alleles an individual possessed and ED status (Sommers' D P value = 1.7 Multiplication-Sign 10{sup -29}). A 1-allele increase in cumulative SNP score increased the odds for developing ED by a factor of 2.2 (P value = 2.1 Multiplication-Sign 10{sup -19}). The cumulative SNP score model had a sensitivity of 84% and specificity of 75% for prediction of developing ED at the radiation therapy planning stage. Conclusions: This genome-wide association study identified a set of SNPs that are associated with development of ED following radiation therapy. These candidate genetic predictors warrant more definitive validation in an independent cohort.« less

How to identify and recruit nurses to a survey 14 and 24 years after graduation in a context of scarce data: lessons learnt from the 2012 nurses at work pilot study on nurses' career paths.

PubMed

Addor, Véronique; Jeannin, André; Morin, Diane; Lehmann, Philippe; Jeanneret, Floriane Roulet; Schwendimann, René

2015-03-26

Nursing workforce data are scarce in Switzerland, with no active national registry of nurses. The worldwide nursing shortage is also affecting Switzerland, so that evidence-based results of the nurses at work project on career paths and retention are needed as part of the health care system stewardship; nurses at work is a retrospective cohort study of nurses who graduated in Swiss nursing schools in the last 30 years. Results of the pilot study are presented here (process and feasibility). The objectives are (1) to determine the size and structure of the potential target population by approaching two test-cohorts of nursing graduates (1988 and 1998); (2) to test methods of identifying and reaching them 14 and 24 years after graduation; (3) to compute participation rates, and identify recruitment and participation biases. Graduates' names were retrieved from 26 Swiss nursing schools: 488 nurses from the 1988 cohort and 597 from 1998 were invited to complete a web-based questionnaire. Initial updated addresses (n = 278, seed sample) were found using the Swiss Nursing Association member file. In addition, a snowball method was applied for recruitment, where directly-contacted respondents provided additional names of graduate mates or sent them the invitation. The study was further advertized through the main employers, study partners, and a press release. Participation rate was 26.5% (n = 287), higher for the older cohort of 1988 (29.7%, n = 145) than for 1998 (15.6%, n = 93). Additional nurses (n = 363) not belonging to the test cohorts also answered. All schools were represented among respondents. Only 18 respondents (6%) worked outside nursing or not at all. Among respondents, 94% would 'probably' or 'maybe' agree to participate in the main study. The pilot study demonstrated that targeted nurses could be identified and approached. There is an overwhelming interest in the project from them and from policymakers. Recommendations to increase nurses' participation rate for nurses at work include: (1) to open nurses at work recruitment to all nurses in Switzerland, while recreating cohorts post-hoc for relevant analysis; (2) to define a comprehensive communication strategy with special attention to graduate nurses who are harder to reach.

Establishing integrated rural–urban cohorts to assess air pollution-related health effects in pregnant women, children and adults in Southern India: an overview of objectives, design and methods in the Tamil Nadu Air Pollution and Health Effects (TAPHE) study

PubMed Central

Balakrishnan, Kalpana; Sambandam, Sankar; Ramaswamy, Padmavathi; Ghosh, Santu; Venkatesan, Vettriselvi; Thangavel, Gurusamy; Mukhopadhyay, Krishnendu; Johnson, Priscilla; Paul, Solomon; Puttaswamy, Naveen; Dhaliwal, Rupinder S; Shukla, D K

2015-01-01

Introduction In rapidly developing countries such as India, the ubiquity of air pollution sources in urban and rural communities often results in ambient and household exposures significantly in excess of health-based air quality guidelines. Few efforts, however, have been directed at establishing quantitative exposure–response relationships in such settings. We describe study protocols for The Tamil Nadu Air Pollution and Health Effects (TAPHE) study, which aims to examine the association between fine particulate matter (PM2.5) exposures and select maternal, child and adult health outcomes in integrated rural–urban cohorts. Methods and analyses The TAPHE study is organised into five component studies with participants drawn from a pregnant mother–child cohort and an adult cohort (n=1200 participants in each cohort). Exposures are assessed through serial measurements of 24–48 h PM2.5 area concentrations in household microenvironments together with ambient measurements and time-activity recalls, allowing exposure reconstructions. Generalised additive models will be developed to examine the association between PM2.5 exposures, maternal (birth weight), child (acute respiratory infections) and adult (chronic respiratory symptoms and lung function) health outcomes while adjusting for multiple covariates. In addition, exposure models are being developed to predict PM2.5 exposures in relation to household and community level variables as well as to explore inter-relationships between household concentrations of PM2.5 and air toxics. Finally, a bio-repository of peripheral and cord blood samples is being created to explore the role of gene–environment interactions in follow-up studies. Ethics and dissemination The study protocols have been approved by the Institutional Ethics Committee of Sri Ramachandra University, the host institution for the investigators in this study. Study results will be widely disseminated through peer-reviewed publications and scientific presentations. In addition, policy-relevant recommendations are also being planned to inform ongoing national air quality action plans concerning ambient and household air pollution. PMID:26063570

Insomnia and the risk of depression: a meta-analysis of prospective cohort studies.

PubMed

Li, Liqing; Wu, Chunmei; Gan, Yong; Qu, Xianguo; Lu, Zuxun

2016-11-05

Observational studies suggest that insomnia might be associated with an increased risk of depression with inconsistent results. This study aimed at conducting a meta-analysis of prospective cohort studies to evaluate the association between insomnia and the risk of depression. Relevant cohort studies were comprehensively searched from the PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases (up to October 2014) and from the reference lists of retrieved articles. A random-effects model was used to calculate the pooled risk estimates and 95 % confidence intervals (CIs). The I 2 statistic was used to assess the heterogeneity and potential sources of heterogeneity were assessed with meta-regression. The potential publication bias was explored by using funnel plots, Egger's test, and Duval and Tweedie trim-and-fill methods. Thirty-four cohort studies involving 172,077 participants were included in this meta-analysis with an average follow-up period of 60.4 months (ranging from 3.5 to 408). Statistical analysis suggested a positive relationship between insomnia and depression, the pooled RR was 2.27 (95 % CI: 1.89-2.71), and a high heterogeneity was observed (I 2  = 92.6 %, P < 0.001). Visual inspection of the funnel plot revealed some asymmetry. The Egger's test identified evidence of substantial publication bias (P <0.05), but correction for this bias using trim-and-fill method did not alter the combined risk estimates. This meta-analysis indicates that insomnia is significantly associated with an increased risk of depression, which has implications for the prevention of depression in non-depressed individuals with insomnia symptoms.

Chronic obstructive pulmonary disease history assessment in Spain: a multidimensional chronic obstructive pulmonary disease evaluation. Study methods and organization.

PubMed

López-Campos, José Luis; Peces-Barba, Germán; Soler-Cataluña, Juan José; Soriano, Joan B; de Lucas Ramos, Pilar; de-Torres, Juan P; Marín, José M; Casanova, Ciro

2012-12-01

This present paper describes the method and the organization of the study known as the COPD History Assessment In SpaiN (CHAIN), whose main objective is to evaluate the long-term natural history of a chronic obstructive pulmonary disease (COPD) patient cohort from a multidimensional standpoint and to identify clinical phenotypes, in comparison with another non-COPD control cohort. CHAIN is a multicenter, observational study of prospective cohorts carried out at 36 Spanish hospitals. Both cohorts will be followed-up during a 5-year study period with complete office visits every 12 months and telephone interviews every 6 months in order to evaluate exacerbations and the vital state of the subjects. The recruitment period for cases was between 15 January 2010 and 31 March 2012. At each annual visit, information will be collected on: (i) clinical aspects (socio-economic situation, anthropometric data, comorbidities, smoking, respiratory symptoms, exacerbations, quality of life, anxiety-depression scale, daily life activities, treatments); (ii) respiratory function (spirometry, blood gases, hyperinflation, diffusion, respiratory pressures); (iii) BODE index (main study variable); (iv) peripheral muscle function, and (v) blood work-up (including IgE and cardiovascular risk factors). In addition, a serum bank will be created for the future determination of biomarkers. The data of the patients are anonymized in a database with a hierarchical access control in order to guarantee secure information access. The CHAIN study will provide information about the progression of COPD and it will establish a network of researchers for future projects related with COPD. Copyright © 2012 SEPAR. Published by Elsevier Espana. All rights reserved.

Design and methods of a postmarketing pharmacoepidemiology study assessing long-term safety of Prolia® (denosumab) for the treatment of postmenopausal osteoporosis.

PubMed

Xue, Fei; Ma, Haijun; Stehman-Breen, Catherine; Haller, Christine; Katz, Leonid; Wagman, Rachel B; Critchlow, Cathy W

2013-10-01

To describe the rationale and methods for a prospective, open-cohort study assessing the long-term safety of Prolia(®) for treatment of postmenopausal osteoporosis (PMO) in postmarketing settings. Data will be derived from United States Medicare, United Healthcare, and Nordic (Denmark, Sweden, Norway) national registries. Observation will begin on the date of first Prolia(®) regulatory approval (May 26, 2010) and continue for 10 years. Women with PMO will be identified by postmenopausal age, osteoporosis diagnosis, osteoporotic fracture, or osteoporosis treatment. Exposure to Prolia(®) and bisphosphonates will be updated during follow-up; exposure cohorts will be defined based on patient-years during which patients are on- or post-treatment. Nine adverse events (AEs) will be assessed based on diagnosis codes: osteonecrosis of the jaw (ONJ), atypical femoral fracture (AFF), fracture healing complications, hypocalcemia, infection, dermatologic AEs, acute pancreatitis, hypersensitivity, and new primary malignancy. Medical review will confirm selected potential cases of ONJ and AFF. Incidence rates (IRs) of AEs will be described overall and for exposure cohorts; multivariate Cox proportional hazard regression models will compare IRs of AEs across exposure cohorts. Utilization patterns of Prolia(®) for approved, and unapproved indications will be described. This study is based on comprehensive preliminary research and considers methodological challenges specific to the study population. The integrated data systems used in this regulatory committed program can serve as a powerful data resource to assess diverse and rare AEs over time. © 2013 Amgen Inc. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons, Ltd.

Cohort profile: Study of Transition, Outcomes and Gender (STRONG) to assess health status of transgender people

PubMed Central

Quinn, Virginia P; Nash, Rebecca; Hunkeler, Enid; Contreras, Richard; Cromwell, Lee; Becerra-Culqui, Tracy A; Getahun, Darios; Giammattei, Shawn; Lash, Timothy L; Millman, Andrea; Robinson, Brandi; Roblin, Douglas; Silverberg, Michael J; Slovis, Jennifer; Tangpricha, Vin; Tolsma, Dennis; Valentine, Cadence; Ward, Kevin; Winter, Savannah; Goodman, Michael

2017-01-01

Purpose The Study of Transition, Outcomes and Gender (STRONG) was initiated to assess the health status of transgender people in general and following gender-affirming treatments at Kaiser Permanente health plans in Georgia, Northern California and Southern California. The objectives of this communication are to describe methods of cohort ascertainment and data collection and to characterise the study population. Participants A stepwise methodology involving computerised searches of electronic medical records and free-text validation of eligibility and gender identity was used to identify a cohort of 6456 members with first evidence of transgender status (index date) between 2006 and 2014. The cohort included 3475 (54%) transfeminine (TF), 2892 (45%) transmasculine (TM) and 89 (1%) members whose natal sex and gender identity remained undetermined from the records. The cohort was matched to 127 608 enrollees with no transgender evidence (63 825 women and 63 783 men) on year of birth, race/ethnicity, study site and membership year of the index date. Cohort follow-up extends through the end of 2016. Findings to date About 58% of TF and 52% of TM cohort members received hormonal therapy at Kaiser Permanente. Chest surgery was more common among TM participants (12% vs 0.3%). The proportions of transgender participants who underwent genital reconstruction surgeries were similar (4%–5%) in the two transgender groups. Results indicate that there are sufficient numbers of events in the TF and TM cohorts to further examine mental health status, cardiovascular events, diabetes, HIV and most common cancers. Future plans STRONG is well positioned to fill existing knowledge gaps through comparisons of transgender and reference populations and through analyses of health status before and after gender affirmation treatment. Analyses will include incidence of cardiovascular disease, mental health, HIV and diabetes, as well as changes in laboratory-based endpoints (eg, polycythemia and bone density), overall and in relation to gender affirmation therapy. PMID:29284718

Glaucoma Structural and Functional Progression in American and Korean Cohorts

PubMed Central

Kostanyan, Tigran; Sung, Kyung Rim; Schuman, Joel S.; Ling, Yun; Lucy, Katie A.; Bilonick, Richard A.; Ishikawa, Hiroshi; Kagemann, Larry; Lee, Jin Y.; Wollstein, Gadi

2016-01-01

Objective To compare the rate of glaucoma structural and functional progression in American and Korean cohorts. Design Retrospective longitudinal study. Participants 313 eyes from 189 glaucoma and glaucoma suspects, followed for an average of 38 months. Methods All subjects were examined semiannually with visual field (VF) testing and spectral-domain optical coherence tomography. All subjects had ≥5 reliable visits. Main Outcome Measurements The rates of change of retinal nerve fiber layer (RNFL) thickness, cup-to-disc (C/D) ratios, and VF mean deviation (MD) were compared between the cohorts. Variables affecting the rate of change for each parameter were determined, including ethnicity, refraction, baseline age and severity, disease subtype (high vs. normal tension glaucoma), clinical diagnosis (glaucoma vs. glaucoma suspect), and the interactions between variables. Results The Korean cohort was predominantly normal tension glaucoma, while the American cohort was high tension glaucoma. Cohorts had similar VF parameters at baseline, but the Korean eyes had significantly thinner mean RNFL and larger cups. Korean glaucoma eyes showed a faster thinning of mean RNFL (mean: −0.71 vs. −0.24μm/year, p<0.01). There was no detectable difference in the rate of change between the glaucoma cohorts for C/D ratios and VF MD and for all parameters in glaucoma suspect eyes. Different combinations of the tested variables significantly impacted the rate of change. Conclusion Ethnicity, baseline severity, disease subtype, and clinical diagnosis should be considered when comparing glaucoma progression studies. PMID:26778345

Association between Kawasaki Disease and Autism: A Population-Based Study in Taiwan

PubMed Central

Kuo, Ho-Chang; Wu, Chung-Min; Chang, Wei-Pin; Kuo, Chun-Nan; Yeter, Deniz; Lin, Chun-Yi; Pai, Jei-Tsung; Chi, Ying-Chen; Lin, Chia-Hsien; Wang, Liang-Jen; Chang, Wei-Chiao

2014-01-01

Objective: The association between Kawasaki disease and autism has rarely been studied in Asian populations. By using a nationwide Taiwanese population-based claims database, we tested the hypothesis that Kawasaki disease may increase the risk of autism in Taiwan. Materials and Methods: Our study cohort consisted of patients who had received the diagnosis of Kawasaki disease (ICD-9-CM: 446.1) between 1997 and 2005 (N = 563). For a comparison cohort, five age- and gender-matched control patients for every patient in the study cohort were selected using random sampling (N = 2,815). All subjects were tracked for 5 years from the date of cohort entry to identify whether they had developed autism (ICD-9-CM code 299.0) or not. Cox proportional hazard regressions were then performed to evaluate 5-year autism-free survival rates. Results: The main finding of this study was that patients with Kawasaki disease seem to not be at increased risk of developing autism. Of the total patients, four patients developed autism during the 5-year follow-up period, among whom two were Kawasaki disease patients and two were in the comparison cohort. Further, the adjusted hazard ratios (AHR) (AHR: 4.81; 95% confidence interval: 0.68–34.35; P = 0.117) did not show any statistical significance between the Kawasaki disease group and the control group during the 5-year follow-up. Conclusion: Our study indicated that patients with Kawasaki disease are not at increased risk of autism. PMID:24705358

Bipolar Disorder Center for Pennsylvanians: Implementing an Effectiveness Trial to Improve Treatment for At-Risk Patients

PubMed Central

Kupfer, David J.; Friedman, Edward S.; Reynolds, Charles F.; Axelson, David A.; Grochocinski, Victoria J.; Stofko, Mary G.; Birmaher, Boris; Houck, Patricia R.; Swartz, Holly A.; Brown, Charlotte; Kilbourne, Amy M.; Thase, Michael E.; Curet, David E.; Mulsant, Benoit H.; Turkin, Scott R.; Fagiolini, Andrea; Pollock, Bruce G.; Whyte, Ellen M.; Frank, Ellen

2012-01-01

Objective Adolescents, elderly persons, African Americans, and rural residents with bipolar disorder are less likely than their middle-aged, white, urban counterparts to be diagnosed, receive adequate treatment, remain in treatment once identified, and have positive outcomes. The Bipolar Disorder Center for Pennsylvanians (BDCP) study was designed to address these disparities. This report highlights the methods used to recruit, screen, and enroll a cohort of difficult-to-recruit individuals with bipolar disorder. Methods Study sites included three specialty clinics for bipolar disorder in a university setting and a rural behavioral health clinic. Study operations were standardized, and all study personnel were trained in study procedures. Several strategies were used for recruitment. Results It was possible to introduce the identical assessment and screening protocol in settings regardless of whether they had a history of implementing research protocols. This protocol was also able to be used across the age spectrum, in urban and rural areas, and in a racially diverse cohort of participants. Across the four sites 515 individuals with bipolar disorder were enrolled as a result of these methods (69 African Americans and 446 non–African Americans). Although clinical characteristics at study entry did not differ appreciably between African Americans and non–African Americans, the pathways into treatment differed significantly. Conclusions Rigorous recruitment and assessment procedures can be successfully introduced in different settings and with different patient cohorts, thus facilitating access to high-quality treatment for individuals who frequently do not receive appropriate care for bipolar disorder. PMID:19564218

Primary aldosteronism and thyroid disorders in atrial fibrillation: A Swedish nationwide case-control study.

PubMed

Mourtzinis, Georgios; Adamsson Eryd, Samuel; Rosengren, Annika; Björck, Lena; Adiels, Martin; Johannsson, Gudmundur; Manhem, Karin

2018-05-01

Background Atrial fibrillation is associated with hyperthyroidism. Patients with primary aldosteronism have an increased prevalence of atrial fibrillation. However, the prevalence of primary aldosteronism in the atrial fibrillation population is unknown. Aim This nationwide case-control study aimed to compare the prevalence of primary aldosteronism and thyroid disorders in patients with atrial fibrillation with that of age- and sex-matched controls. Methods We identified all atrial fibrillation cases in Sweden between 1987 and 2013 ( n = 713,569) by using the Swedish National Patient Register. A control cohort without atrial fibrillation was randomly selected from the Swedish Total Population Register with a case to control ratio of 1:2. This control cohort was matched for age, sex and place of birth ( n = 1,393,953). Results The prevalence of primary aldosteronism in December 2013 was 0.056% in the atrial fibrillation cohort and 0.024% in controls. At the same time, the prevalence of hypothyroidism was 5.9% in the atrial fibrillation cohort and 3.7% in controls. The prevalence of hyperthyroidism was 2.3% in the atrial fibrillation cohort and 0.8% in controls. Conclusion This study shows, for the first time, a doubled prevalence of primary aldosteronism in a large cohort of patients with atrial fibrillation compared with the general population. There is also an increased prevalence of hypo- and hyper-thyroidism in patients with atrial fibrillation compared with the general population.

Laboratory-based versus non-laboratory-based method for assessment of cardiovascular disease risk: the NHANES I Follow-up Study cohort

PubMed Central

Gaziano, Thomas A; Young, Cynthia R; Fitzmaurice, Garrett; Atwood, Sidney; Gaziano, J Michael

2008-01-01

Summary Background Around 80% of all cardiovascular deaths occur in developing countries. Assessment of those patients at high risk is an important strategy for prevention. Since developing countries have limited resources for prevention strategies that require laboratory testing, we assessed if a risk prediction method that did not require any laboratory tests could be as accurate as one requiring laboratory information. Methods The National Health and Nutrition Examination Survey (NHANES) was a prospective cohort study of 14 407 US participants aged between 25–74 years at the time they were first examined (between 1971 and 1975). Our follow-up study population included participants with complete information on these surveys who did not report a history of cardiovascular disease (myocardial infarction, heart failure, stroke, angina) or cancer, yielding an analysis dataset N=6186. We compared how well either method could predict first-time fatal and non-fatal cardiovascular disease events in this cohort. For the laboratory-based model, which required blood testing, we used standard risk factors to assess risk of cardiovascular disease: age, systolic blood pressure, smoking status, total cholesterol, reported diabetes status, and current treatment for hypertension. For the non-laboratory-based model, we substituted body-mass index for cholesterol. Findings In the cohort of 6186, there were 1529 first-time cardiovascular events and 578 (38%) deaths due to cardiovascular disease over 21 years. In women, the laboratory-based model was useful for predicting events, with a c statistic of 0·829. The c statistic of the non-laboratory-based model was 0·831. In men, the results were similar (0·784 for the laboratory-based model and 0·783 for the non-laboratory-based model). Results were similar between the laboratory-based and non-laboratory-based models in both men and women when restricted to fatal events only. Interpretation A method that uses non-laboratory-based risk factors predicted cardiovascular events as accurately as one that relied on laboratory-based values. This approach could simplify risk assessment in situations where laboratory testing is inconvenient or unavailable. PMID:18342687

Association between hyperglycaemic crisis and long-term major adverse cardiovascular events: a nationwide population-based, propensity score-matched, cohort study

PubMed Central

Chang, Li-Hsin; Lin, Liang-Yu; Tsai, Ming-Tsun; How, Chorng-Kuang; Chiang, Jen-Huai; Hsieh, Vivian Chia-Rong; Hu, Sung-Yuan; Hsieh, Ming-Shun

2016-01-01

Objective Hyperglycaemic crisis was associated with significant intrahospital morbidity and mortality. However, the association between hyperglycaemic crisis and long-term cardiovascular outcomes remained unknown. This study aimed to investigate the association between hyperglycaemic crisis and subsequent long-term major adverse cardiovascular events (MACEs). Participants and methods This population-based cohort study was conducted using data from Taiwan's National Health Insurance Research Database for the period of 1996–2012. A total of 2171 diabetic patients with hyperglycaemic crisis fit the inclusion criteria. Propensity score matching was used to match the baseline characteristics of the study cohort to construct a comparison cohort which comprised 8684 diabetic patients without hyperglycaemic crisis. The risk of long-term MACEs was compared between the two cohorts. Results Six hundred and seventy-six MACEs occurred in the study cohort and the event rate was higher than that in the comparison cohort (31.1% vs 24.1%, p<0.001). Patients with hyperglycaemic crisis were associated with a higher risk of long-term MACEs even after adjusting for all baseline characteristics and medications (adjusted HR=1.76, 95% CI 1.62 to 1.92, p<0.001). Acute myocardial infarction had the highest adjusted HR (adjusted HR=2.19, 95% CI 1.75 to 2.75, p<0.001) in the four types of MACEs, followed by congestive heart failure (adjusted HR=1.97, 95% CI 1.70 to 2.28, p<0.001). Younger patients with hyperglycaemic crisis had a higher risk of MACEs than older patients (adjusted HR=2.69 for patients aged 20–39 years vs adjusted HR=1.58 for patients aged >65 years). Conclusions Hyperglycaemic crisis was significantly associated with long-term MACEs, especially in the young population. Further prospective longitudinal study should be conducted for validation. PMID:27554106

Cerebral microbleeds and recurrent stroke risk: systematic review and meta-analysis of prospective ischemic stroke and transient ischemic attack cohorts.

PubMed

Charidimou, Andreas; Kakar, Puneet; Fox, Zoe; Werring, David J

2013-04-01

To evaluate cerebral microbleeds (CMBs) and future stroke risk (including intracerebral hemorrhage [ICH]) in patients with ischemic stroke (IS) or transient ischemic attack. A systematic review and meta-analysis of prospective cohorts with recent IS/transient ischemic attack. We critically appraised studies and calculated pooled odds ratios (ORs), using the Mantel-Haenszel fixed-effects method, for ICH or recurrent IS, in patients with versus without CMBs. We pooled data from 10 cohorts, including 3067 patients. CMBs were associated with a significant increased risk of any recurrent stroke (OR, 2.25; 95% confidence interval [95% CI], 1.70-2.98; P<0.0001), ICH (OR, 8.52; 95%CI, 4.23-17.18; P=0.007), and IS (OR, 1.55; 95%CI, 1.12-2.13; P<0.0001). When stratified by study population ethnicity (Asian versus Western [mainly white European]), the association of CMBs with ICH was significant for Asian cohorts (5 studies; n=1915; OR, 10.43; 95%CI, 4.59-23.72; P<0.0001) but borderline and of lower magnitude for Western cohorts (4 studies; n=885; OR, 3.87; 95%CI, 0.91-16.4; P=0.066). By contrast, there was a significant association of CMBs with recurrent IS in Western (3 studies; n=899) but not Asian cohorts (4 studies; n=1357; OR, 2.23; 95%CI, 1.29-3.85; P=0.004 compared with OR, 1.30; 95%CI, 0.88-1.93; P=0.192, respectively). There is consistent evidence of an increased risk of recurrent stroke after IS or transient ischemic attack in patients with CMBs. The risk for spontaneous ICH appears to be greater than the risk for recurrent IS. Our findings also suggest that the balance of risk for ICH versus IS differs between Asian and Western cohorts.

New Exposure Biomarkers as Tools for Breast Cancer Epidemiology, Biomonitoring, and Prevention: A Systematic Approach Based on Animal Evidence

PubMed Central

Ackerman, Janet M.; Attfield, Kathleen R.; Brody, Julia Green

2014-01-01

Background: Exposure to chemicals that cause rodent mammary gland tumors is common, but few studies have evaluated potential breast cancer risks of these chemicals in humans. Objective: The goal of this review was to identify and bring together the needed tools to facilitate the measurement of biomarkers of exposure to potential breast carcinogens in breast cancer studies and biomonitoring. Methods: We conducted a structured literature search to identify measurement methods for exposure biomarkers for 102 chemicals that cause rodent mammary tumors. To evaluate concordance, we compared human and animal evidence for agents identified as plausibly linked to breast cancer in major reviews. To facilitate future application of exposure biomarkers, we compiled information about relevant cohort studies. Results: Exposure biomarkers have been developed for nearly three-quarters of these rodent mammary carcinogens. Analytical methods have been published for 73 of the chemicals. Some of the remaining chemicals could be measured using modified versions of existing methods for related chemicals. In humans, biomarkers of exposure have been measured for 62 chemicals, and for 45 in a nonoccupationally exposed population. The Centers for Disease Control and Prevention has measured 23 in the U.S. population. Seventy-five of the rodent mammary carcinogens fall into 17 groups, based on exposure potential, carcinogenicity, and structural similarity. Carcinogenicity in humans and rodents is generally consistent, although comparisons are limited because few agents have been studied in humans. We identified 44 cohort studies, with a total of > 3.5 million women enrolled, that have recorded breast cancer incidence and stored biological samples. Conclusions: Exposure measurement methods and cohort study resources are available to expand biomonitoring and epidemiology related to breast cancer etiology and prevention. Citation: Rudel RA, Ackerman JM, Attfield KR, Brody JG. 2014. New exposure biomarkers as tools for breast cancer epidemiology, biomonitoring, and prevention: a systematic approach based on animal evidence. Environ Health Perspect 122:881–895; http://dx.doi.org/10.1289/ehp.1307455 PMID:24818537

A Comparison of Different Methods for Evaluating Diet, Physical Activity, and Long-Term Weight Gain in 3 Prospective Cohort Studies.

PubMed

Smith, Jessica D; Hou, Tao; Hu, Frank B; Rimm, Eric B; Spiegelman, Donna; Willett, Walter C; Mozaffarian, Dariush

2015-11-01

The insidious pace of long-term weight gain (∼ 1 lb/y or 0.45 kg/y) makes it difficult to study in trials; long-term prospective cohorts provide crucial evidence on its key contributors. Most previous studies have evaluated how prevalent lifestyle habits relate to future weight gain rather than to lifestyle changes, which may be more temporally and physiologically relevant. Our objective was to evaluate and compare different methodological approaches for investigating diet, physical activity (PA), and long-term weight gain. In 3 prospective cohorts (total n = 117,992), we assessed how lifestyle relates to long-term weight change (up to 24 y of follow-up) in 4-y periods by comparing 3 analytic approaches: 1) prevalent diet and PA and 4-y weight change (prevalent analysis); 2) 4-y changes in diet and PA with a 4-y weight change (change analysis); and 3) 4-y change in diet and PA with weight change in the subsequent 4 y (lagged-change analysis). We compared these approaches and evaluated the consistency across cohorts, magnitudes of associations, and biological plausibility of findings. Across the 3 methods, consistent, robust, and biologically plausible associations were seen only for the change analysis. Results for prevalent or lagged-change analyses were less consistent across cohorts, smaller in magnitude, and biologically implausible. For example, for each serving of a sugar-sweetened beverage, the observed weight gain was 0.01 lb (95% CI: -0.08, 0.10) [0.005 kg (95% CI: -0.04, 0.05)] based on prevalent analysis; 0.99 lb (95% CI: 0.83, 1.16) [0.45 kg (95% CI: 0.38, 0.53)] based on change analysis; and 0.05 lb (95% CI: -0.10, 0.21) [0.02 kg (95% CI: -0.05, 0.10)] based on lagged-change analysis. Findings were similar for other foods and PA. Robust, consistent, and biologically plausible relations between lifestyle and long-term weight gain are seen when evaluating lifestyle changes and weight changes in discrete periods rather than in prevalent lifestyle or lagged changes. These findings inform the optimal methods for evaluating lifestyle and long-term weight gain and the potential for bias when other methods are used. © 2015 American Society for Nutrition.

Do Stem Taper Microgrooves Influence Taper Corrosion in Total Hip Arthroplasty? A Matched Cohort Retrieval Study.

PubMed

Arnholt, Christina M; MacDonald, Daniel W; Underwood, Richard J; Guyer, Eric P; Rimnac, Clare M; Kurtz, Steven M; Mont, Michael A; Klein, Gregg R; Lee, Gwo-Chin; Chen, Antonia F; Hamlin, Brian R; Cates, Harold E; Malkani, Arthur L; Kraay, Matthew J

2017-04-01

Previous studies identified imprinting of the stem morphology onto the interior head bore, leading researchers to hypothesize an influence of taper topography on mechanically assisted crevice corrosion. The purpose of this study was to analyze whether microgrooved stem tapers result in greater fretting corrosion damage than smooth stem tapers. A matched cohort of 120 retrieved head-stem pairs from metal-on-polyethylene bearings was created controlling for implantation time, flexural rigidity, apparent length of engagement, and head size. There were 2 groups of 60 heads each, mated with either smooth or microgrooved stem tapers. A high-precision roundness machine was used to measure and categorize the surface morphology. Fretting corrosion damage at the head-neck junction was characterized using the Higgs-Goldberg scoring method. Fourteen of the most damaged heads were analyzed for the maximum depth of material loss and focused ion beam cross-sectioned to view oxide and base metal. Fretting corrosion damage was not different between the 2 cohorts at the femoral head (P = .14, Mann-Whitney) or stem tapers (P = .35). There was no difference in the maximum depths of material loss between the cohorts (P = .71). Cross-sectioning revealed contact damage, signs of micro-motion, and chromium-rich oxide layers in both cohorts. Microgroove imprinting did not appear to have a different effect on the fretting corrosion behavior. The results of this matched cohort retrieval study do not support the hypothesis that taper surfaces with microgrooved stems exhibit increased in vivo fretting corrosion damage or material release. Copyright © 2016 Elsevier Inc. All rights reserved.

Social determinants of lung cancer incidence in Canada: A 13-year prospective study.

PubMed

Mitra, Debjani; Shaw, Amanda; Tjepkema, Michael; Peters, Paul

2015-06-01

The risk of lung cancer has been shown to be inversely related to socioeconomic status (SES). Because the Canadian Cancer Registry does not contain socioeconomic data, the 1991 Canadian Census Cohort was used to study social determinants of lung cancer risk in the general Canadian population. This study examines incidence rates of lung cancer and histologic subtypes by educational attainment, income and occupation in a broadly representative sample of Canadians aged 25 or older. Data for the 1991 Canadian Census Cohort were analyzed. The cohort comprised 2,734,835 individuals, among whom 215,700 new cancer cases were diagnosed from 1991 through 2003. Age-standardized incidence rates were calculated by age, sex, and SES using the direct method. Rate ratios, rate differences, and excess incidence were also calculated. An inverse risk between lung cancer incidence and educational attainment, income and occupation emerged among men and women, and a stepped negative gradient in RRs was evident for all SES variables and age groups. If all cohort members had experienced the rate of those with a university degree, lung cancer incidence would have been 56% lower in men and 55% lower in women. If all cohort members had experienced the incidence rate of those in the highest income quintile, incidence would have been 33% lower in men and 25% lower in women. If all cohort members had experienced the rate of those in managerial occupations, incidence would have been 54% lower in men and 44% lower in women. A negative gradient in lung cancer risk was evident for all SES variables studied.

Protocol for the Women And Their Children’s Health (WATCH) Study: A Cohort of Pregnancy and Beyond

PubMed Central

Hure, Alexis J; Collins, Clare E; Giles, Warwick B; Wright, Ian MR; Smith, Roger

2012-01-01

Background The developmental origins of health and disease is a conceptual framework that helps explain the links between our early life exposures and later health outcomes, and is a burgeoning field of research. In this report, we describe the study protocol used in a prospective cohort of women recruited during pregnancy, with postnatal follow-up of the mothers and offspring. Methods The Women And Their Children’s Health (WATCH) cohort (n = 180 women) is being conducted at the John Hunter Hospital, Australia (from June 2006). Women attended study visits during pregnancy at 19, 24, 30, and 36 weeks’ gestation. Postnatal follow-up of the women and their offspring occurred at 3-month intervals during the first year after birth and annually thereafter, until age 4 years. Fetal ultrasound scans were performed at each pregnancy visit. Pregnancy and birth data were obtained from hospital records. Data collection has included maternal and child anthropometric, biochemical, dietary, physical activity, socioeconomic, medical, and other variables. Conclusions The 2 most novel components of our prospective cohort study are (1) the regular and systematic tracking of fetal and child growth and body composition, starting in the second trimester of pregnancy and continuing to age 4 years, and (2) the detailed maternal and child dietary data collection, including biochemical parameters. Detailed cohorts that collect data on the early nutritional, physiological, and social determinants of health are valuable. Despite its relatively small sample size, many hypotheses on developmental origins can be tested or piloted using data collected from the WATCH cohort. PMID:22374367

Mouse handling limits the impact of stress on metabolic endpoints.

PubMed

Ghosal, Sriparna; Nunley, Amanda; Mahbod, Parinaz; Lewis, Alfor G; Smith, Eric P; Tong, Jenny; D'Alessio, David A; Herman, James P

2015-10-15

Studies focused on end-points that are confounded by stress are best performed under minimally stressful conditions. The objective of this study was to demonstrate the impact of handling designed to reduce animal stress on measurements of glucose tolerance. A cohort of mice (CD1.C57BL/6) naïve to any specific handling was subjected to either a previously described "cup" handling method, or a "tail-picked" method in which the animals were picked up by the tail (as is common for metabolic studies). Following training, an elevated plus maze (EPM) test was performed followed by measurement of blood glucose and plasma corticosterone. A second cohort (CD1.C57BL/6) was rendered obese by exposure to a high fat diet, handled with either the tail-picked or cup method and subjected to an intraperitoneal glucose tolerance test. A third cohort of C57BL/6 mice was exposed to a cup regimen that included a component of massage and was subjected to tests of anxiety-like behavior, glucose homeostasis, and corticosterone secretion. We found that the cup mice showed reduced anxiety-like behaviors in the EPM coupled with a reduction in blood glucose levels compared to mice handled by the tail-picked method. Additionally, cup mice on the high fat diet exhibited improved glucose tolerance compared to tail-picked controls. Finally, we found that the cup/massage group showed lower glucose levels following an overnight fast, and decreased anxiety-like behaviors associated with lower stress-induced plasma corticosterone concentration compared to tail-picked controls. These data demonstrate that application of handling methods that reduce anxiety-like behaviors in mice mitigates the confounding contribution of stress to interpretation of metabolic endpoints (such as glucose tolerance). Copyright © 2015 Elsevier Inc. All rights reserved.

Mouse Handling Limits the Impact of Stress on Metabolic Endpoints

PubMed Central

Ghosal, Sriparna; Nunley, Amanda; Mahbod, Parinaz; Lewis, Alfor G.; Smith, Eric P.; Tong, Jenny; D’Alessio, David A.; Herman, James P.

2015-01-01

Studies focused on end-points that are confounded by stress are best performed under minimally stressful conditions. The objective of this study was to demonstrate the impact of handling designed to reduce animal stress on measurements of glucose tolerance. A cohort of mice (CD1.C57BL/6) naïve to any specific handling were subjected to either a previously described “cup” handling method, or a “tail-picked” method in which the animals were picked up by the tail (as is common for metabolic studies). Following training, an elevated plus maze (EPM) test was performed followed by measurement of blood glucose and plasma corticosterone. A second cohort (CD1.C57BL/6) was rendered obese by exposure to a high fat diet, handled with either the tail-picked or cup method and subjected to an intraperitoneal glucose tolerance test. A third cohort of C57BL/6 mice was exposed to a cup regimen that included a component of massage and was subjected to tests of anxiety-like behavior, glucose homeostasis, and corticosterone secretion. We found that the cup mice showed reduced anxiety-like behaviors in the EPM coupled with a reduction in blood glucose levels compared to mice handled by the tail-picked method. Additionally, cup mice on the high fat diet exhibited improved glucose tolerance compared to tail-picked controls. Finally, we found that the cup/massage group showed lower glucose levels following an overnight fast, and decreased anxiety-like behaviors associated with lower stress-induced plasma corticosterone concentration compared to tail-picked controls. These data demonstrate that application of handling methods that reduce anxiety-like behaviors in mice mitigates the confounding contribution of stress to interpretation of metabolic endpoints (such as glucose tolerance). PMID:26079207

A comparison of entropy balance and probability weighting methods to generalize observational cohorts to a population: a simulation and empirical example.

PubMed

Harvey, Raymond A; Hayden, Jennifer D; Kamble, Pravin S; Bouchard, Jonathan R; Huang, Joanna C

2017-04-01

We compared methods to control bias and confounding in observational studies including inverse probability weighting (IPW) and stabilized IPW (sIPW). These methods often require iteration and post-calibration to achieve covariate balance. In comparison, entropy balance (EB) optimizes covariate balance a priori by calibrating weights using the target's moments as constraints. We measured covariate balance empirically and by simulation by using absolute standardized mean difference (ASMD), absolute bias (AB), and root mean square error (RMSE), investigating two scenarios: the size of the observed (exposed) cohort exceeds the target (unexposed) cohort and vice versa. The empirical application weighted a commercial health plan cohort to a nationally representative National Health and Nutrition Examination Survey target on the same covariates and compared average total health care cost estimates across methods. Entropy balance alone achieved balance (ASMD ≤ 0.10) on all covariates in simulation and empirically. In simulation scenario I, EB achieved the lowest AB and RMSE (13.64, 31.19) compared with IPW (263.05, 263.99) and sIPW (319.91, 320.71). In scenario II, EB outperformed IPW and sIPW with smaller AB and RMSE. In scenarios I and II, EB achieved the lowest mean estimate difference from the simulated population outcome ($490.05, $487.62) compared with IPW and sIPW, respectively. Empirically, only EB differed from the unweighted mean cost indicating IPW, and sIPW weighting was ineffective. Entropy balance demonstrated the bias-variance tradeoff achieving higher estimate accuracy, yet lower estimate precision, compared with IPW methods. EB weighting required no post-processing and effectively mitigated observed bias and confounding. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Exome-chip meta-analysis identifies association between variation in ANKRD26 and platelet aggregation.

PubMed

Chen, Ming-Huei; Yanek, Lisa R; Backman, Joshua D; Eicher, John D; Huffman, Jennifer E; Ben-Shlomo, Yoav; Beswick, Andrew D; Yerges-Armstrong, Laura M; Shuldiner, Alan R; O'Connell, Jeffrey R; Mathias, Rasika A; Becker, Diane M; Becker, Lewis C; Lewis, Joshua P; Johnson, Andrew D; Faraday, Nauder

2017-11-29

Previous genome-wide association studies (GWAS) have identified several variants associated with platelet function phenotypes; however, the proportion of variance explained by the identified variants is mostly small. Rare coding variants, particularly those with high potential for impact on protein structure/function, may have substantial impact on phenotype but are difficult to detect by GWAS. The main purpose of this study was to identify low frequency or rare variants associated with platelet function using genotype data from the Illumina HumanExome Bead Chip. Three family-based cohorts of European ancestry, including ~4,000 total subjects, comprised the discovery cohort and two independent cohorts, one of European and one of African American ancestry, were used for replication. Optical aggregometry in platelet-rich plasma was performed in all the discovery cohorts in response to adenosine diphosphate (ADP), epinephrine, and collagen. Meta-analyses were performed using both gene-based and single nucleotide variant association methods. The gene-based meta-analysis identified a significant association (P = 7.13 × 10 -7 ) between rare genetic variants in ANKRD26 and ADP-induced platelet aggregation. One of the ANKRD26 SNVs - rs191015656, encoding a threonine to isoleucine substitution predicted to alter protein structure/function, was replicated in Europeans. Aggregation increases of ~20-50% were observed in heterozygotes in all cohorts. Novel genetic signals in ABCG1 and HCP5 were also associated with platelet aggregation to ADP in meta-analyses, although only results for HCP5 could be replicated. The SNV in HCP5 intersects epigenetic signatures in CD41+ megakaryocytes suggesting a new functional role in platelet biology for HCP5. This is the first study to use gene-based association methods from SNV array genotypes to identify rare variants related to platelet function. The molecular mechanisms and pathophysiological relevance for the identified genetic associations requires further study.

Maternal Health Risk Assessment and Behavioral Intervention in the NICU Setting Following Very Low Birth Weight Delivery.

PubMed

Dunlop, Anne L; Logue, Kristi; Thorne, Castalia

2016-11-01

Objectives To investigate whether maternal health risk assessment and behavioral intervention in the neonatal intensive care unit (NICU) improves women's health care seeking and health behaviors following the birth of a very low birth weight (VLBW) infant. Methods Using a quasi-experimental non-equivalent control group pretest/posttest design, 80 women who had given birth to a VLBW infant that was admitted to the NICU were enrolled into one of two cohorts: 40 into a 'Minimal Intervention' cohort, who received a single session risk assessment and health education pamphlets, and 40 into an 'Enhanced Intervention' cohort, who received five counseling sessions targeting identified risks. The proportion of women with specific health care seeking and health behaviors in the two cohorts were compared at baseline and 3- and 9-months post-intervention. Results Women in the Enhanced Intervention cohort were more likely to attend the postpartum visit (73 % vs. 48 %; p = 0.04), ingest folic acid daily (65 % vs. 19 %, p < 0.001), and correctly and consistently use a method of contraception (82 % vs. 63 %, p = 0.03) over the 9-month follow-up period. In multivariate analysis, the between-cohort differences in daily folic acid use (aOR = 3.45, 95 % CI 1.61-7.40) and correct and consistent use of a method of contraception (aOR = 1.46, 95 % CI 1.05-2.06) remained statistically significant at 9-months and the reduction in risk of unintended pregnancy nearly achieved statistical significance (aOR = 0.62, 95 % CI 0.12-1.0). Conclusions for Practice This study provides support for the implementation of maternal risk assessment and behavioral intervention in the NICU setting to promote women's positive health care seeking and health behaviors.

Liver transplant center performance profiling: 2005-2011 reports of the Scientific Registry for Transplant Recipients.

PubMed

Kettelhut, Valeriya V; Nayar, Preethy

2013-06-01

CONTEXT-Transplant center performance profiling provides important information for various concerned parties. Comparing a transplant center's performance against the performance of the best-in-class centers may help in understanding the performance thresholds for the underperforming centers. OBJECTIVES-(1) To identify and describe "Centers for Medicare and Medicaid Services (CMS)-red-flag" performers and the "best-in-class" performers and (2) to examine the relationships between a center's performance profile and outcomes such as 1-year observed mortality, 1-month observed mortality, 1-year risk-adjusted mortality, and volume. METHODS-The data for analysis was obtained from the published reports on the Scientific Registry for Transplant Recipients (SRTR) website for adult liver transplant programs compiled for the rolling 2 1/2-year cohorts of patients and included 7 cohorts of liver transplant recipients in the study from January through July 1, 2002, through December 31, 2010. We defined 4 performance profiles: CMS-red-flag, lower-than-expected, higher-than-expected, and best-in-class performers. RESULTS-The current SRTR methods classify approximately 7% of the adult liver centers as CMS-red-flag performers and 6% of the centers as best-in-class performers in every reported period. Neither of the low-volume centers (<30 liver transplants per 2 1/2-year cohort) was profiled as CMS-red-flag until the 2010 reporting period. The transplant center's profile was significantly associated with the 1-year and 1-month observed mortality rates in every reported cohort (P< .001). CONCLUSION-The CMS-red-flag profile can be characterized with the following: (1) the highest observed 1-year mortality, (2) the highest observed 1-month mortality, (3) a very large difference between the observed and adjusted mortality rates, and (4) the center volume greater than 30 liver transplants per 2 1/2-year cohort. The SRTR methods are not sensitive for performance profiling in the centers that perform fewer than 30 orthotopic liver transplants per 2 1/2-year cohort.

Recruiting black Americans in a large cohort study: the Adventist Health Study-2 (AHS-2) design, methods and participant characteristics.

PubMed

Herring, R Patti; Butler, Terry; Hall, Sonja; Montgomery, Susanne B; Fraser, Gary E

2010-01-01

The goal of the prospective Adventist Health Study-2 (AHS-2) was to examine the relationship between diet and risk of breast, prostate and colon cancers in Black and White participants. This paper describes the study design, recruitment methods, response rates, and characteristics of Blacks in the AHS-2, thus providing insights about effective strategies to recruit Blacks to participate in research studies. We designed a church-based recruitment model and trained local recruiters who used various strategies to recruit participants in their churches. Participants completed a 50-page self-administered dietary and lifestyle questionnaire. Participants are Black Seventh-day Adventists, aged 30-109 years, and members of 1,209 Black churches throughout the United States and Canada. Approximately 48,328 Blacks from an estimated target group of over 90,000 signed up for the study and 25,087 completed the questionnaire, comprising about 26% of the larger 97,000 AHS-2-member cohort. Participants were diverse in age, geographic location, education, and income. Seventy percent were female with a median age of 59 years. In spite of many recruitment challenges and barriers, we successfully recruited a large cohort whose data should provide some answers as to why Blacks have poorer health outcomes than several other ethnic groups, and help explain existing health disparities.

Recruiting Black Americans in a Large Cohort Study: The Adventist Health Study-2 (AHS-2) Design, Methods and Participant Characteristics

PubMed Central

Herring, R. Patti; Butler, Terry; Hall, Sonja; Montgomery, Susanne B.; Fraser, Gary E.

2011-01-01

Objective The goal of the prospective Adventist Health Study-2 (AHS-2) was to examine the relationship between diet and risk of breast, prostate and colon cancers in Black and White participants. This paper describes the study design, recruitment methods, response rates, and characteristics of Blacks in the AHS-2, thus providing insights about effective strategies to recruit Blacks to participate in research studies. Design We designed a church-based recruitment model and trained local recruiters who used various strategies to recruit participants in their churches. Participants completed a 50-page self-administered dietary and lifestyle questionnaire. Participants Participants are Black Seventh-day Adventists, aged 30–109 years, and members of 1,209 Black churches throughout the United States and Canada. Results Approximately 48,328 Blacks from an estimated target group of over 90,000 signed up for the study and 25,087 completed the questionnaire, comprising about 26% of the larger 97,000 AHS-2-member cohort. Participants were diverse in age, geographic location, education, and income. Seventy percent were female with a median age of 59 years. Conclusion In spite of many recruitment challenges and barriers, we successfully recruited a large cohort whose data should provide some answers as to why Blacks have poorer health outcomes than several other ethnic groups, and help explain existing health disparities. PMID:21305834

Systematic review of birth cohort studies in Africa

PubMed Central

Campbell, Alasdair; Rudan, Igor

2011-01-01

Aim In sub-Saharan Africa, unacceptably high rates of mortality amongst women and children continue to persist. The emergence of research employing new genomic technologies is advancing knowledge on cause of disease. This review aims to identify birth cohort studies conducted in sub-Saharan Africa and to consider their suitability as a platform to support genetic epidemiological studies. Methods A systematic literature review was conducted to identify birth cohort studies in sub-Saharan Africa across the following databases: MEDLINE, EMBASE, AFRO and OpenSIGLE. A total of 8110 papers were retrieved. Application of inclusion/exclusion criteria retained only 189 papers, of which 71 met minimum quality criteria and were retained for full text analysis. Results The search revealed 28 birth cohorts: 14 of which collected biological data, 10 collected blood samples and only one study collected DNA for storage. These studies face many methodological challenges: notably, high rates of attrition and lack of funding for several rounds of study follow up. Population-based ‘biobanks’ have emerged as a major approach to harness genomic technologies in health research and yet the sub-Saharan African region still awaits large scale birth cohort biobanks collecting DNA and associated health and lifestyle data. Conclusion Investment in this field, together with related endeavours to foster and develop research capacity for these studies, may lead to an improved understanding of the determinants of intrauterine growth and development, birth outcomes such as prematurity and low birth weight, the links between maternal and infant health, survival of infectious diseases in the first years of life, and response to vaccines and antibiotic treatment. PMID:23198102

The two-dimensional Monte Carlo: a new methodologic paradigm for dose reconstruction for epidemiological studies.

PubMed

Simon, Steven L; Hoffman, F Owen; Hofer, Eduard

2015-01-01

Retrospective dose estimation, particularly dose reconstruction that supports epidemiological investigations of health risk, relies on various strategies that include models of physical processes and exposure conditions with detail ranging from simple to complex. Quantification of dose uncertainty is an essential component of assessments for health risk studies since, as is well understood, it is impossible to retrospectively determine the true dose for each person. To address uncertainty in dose estimation, numerical simulation tools have become commonplace and there is now an increased understanding about the needs and what is required for models used to estimate cohort doses (in the absence of direct measurement) to evaluate dose response. It now appears that for dose-response algorithms to derive the best, unbiased estimate of health risk, we need to understand the type, magnitude and interrelationships of the uncertainties of model assumptions, parameters and input data used in the associated dose estimation models. Heretofore, uncertainty analysis of dose estimates did not always properly distinguish between categories of errors, e.g., uncertainty that is specific to each subject (i.e., unshared error), and uncertainty of doses from a lack of understanding and knowledge about parameter values that are shared to varying degrees by numbers of subsets of the cohort. While mathematical propagation of errors by Monte Carlo simulation methods has been used for years to estimate the uncertainty of an individual subject's dose, it was almost always conducted without consideration of dependencies between subjects. In retrospect, these types of simple analyses are not suitable for studies with complex dose models, particularly when important input data are missing or otherwise not available. The dose estimation strategy presented here is a simulation method that corrects the previous deficiencies of analytical or simple Monte Carlo error propagation methods and is termed, due to its capability to maintain separation between shared and unshared errors, the two-dimensional Monte Carlo (2DMC) procedure. Simply put, the 2DMC method simulates alternative, possibly true, sets (or vectors) of doses for an entire cohort rather than a single set that emerges when each individual's dose is estimated independently from other subjects. Moreover, estimated doses within each simulated vector maintain proper inter-relationships such that the estimated doses for members of a cohort subgroup that share common lifestyle attributes and sources of uncertainty are properly correlated. The 2DMC procedure simulates inter-individual variability of possibly true doses within each dose vector and captures the influence of uncertainty in the values of dosimetric parameters across multiple realizations of possibly true vectors of cohort doses. The primary characteristic of the 2DMC approach, as well as its strength, are defined by the proper separation between uncertainties shared by members of the entire cohort or members of defined cohort subsets, and uncertainties that are individual-specific and therefore unshared.

Cerebral palsy in Victoria: motor types, topography and gross motor function.

PubMed

Howard, Jason; Soo, Brendan; Graham, H Kerr; Boyd, Roslyn N; Reid, Sue; Lanigan, Anna; Wolfe, Rory; Reddihough, Dinah S

2005-01-01

To study the relationships between motor type, topographical distribution and gross motor function in a large, population-based cohort of children with cerebral palsy (CP), from the State of Victoria, and compare this cohort to similar cohorts from other countries. An inception cohort was generated from the Victorian Cerebral Palsy Register (VCPR) for the birth years 1990-1992. Demographic information, motor types and topographical distribution were obtained from the register and supplemented by grading gross motor function according to the Gross Motor Function Classification System (GMFCS). Complete data were obtained on 323 (86%) of 374 children in the cohort. Gross motor function varied from GMFCS level I (35%) to GMFCS level V (18%) and was similar in distribution to a contemporaneous Swedish cohort. There was a fairly even distribution across the topographical distributions of hemiplegia (35%), diplegia (28%) and quadriplegia (37%) with a large majority of young people having the spastic motor type (86%). The VCPR is ideal for population-based studies of gross motor function in children with CP. Gross motor function is similar in populations of children with CP in developed countries but the comparison of motor types and topographical distribution is difficult because of lack of consensus with classification systems. Use of the GMFCS provides a valid and reproducible method for clinicians to describe gross motor function in children with CP using a universal language.

A prospective cohort study of disability pension due to mental diagnoses: the importance of health factors and behaviors

PubMed Central

2013-01-01

Background Previous studies have found associations between various health factors and behaviors and mental disorders. However, knowledge of such associations with disability pension (DP) due to mental diagnoses is scarce. Moreover, the influence of familial factors (genetics and family background) on the associations are mainly unknown. The aim of the study was to investigate associations between health factors and behaviors and future DP due to mental diagnoses in a twin cohort, accounting for familial confounding. Methods A prospective cohort study of Swedish twins (N=28 613), including survey data and national register data on DP and other background factors was conducted. Cox proportional hazards regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for the whole twin cohort, and for discordant twin pairs. Results During follow-up 1998–2008 (median 10 years), 2.2% of the cohort was granted a DP with a mental diagnosis. In the fully adjusted analyses of the whole cohort, the associations of poor or moderate self-rated health (SRH), under- or overweight, former or current tobacco use, or being an abstainer from alcohol were significantly associated with risk of DP due to mental diagnoses. Analyses of discordant twin pairs confirmed all these associations, except for current tobacco use, being independent from familial confounding. Exclusion of individuals with current or previous depression or anxiety at baseline did not influence the associations found. Conclusions Poor or moderate SRH, under- or overweight, former tobacco use or being an abstainer from alcohol seem to be strong direct predictors of DP due to mental diagnoses, independently of several confounders of this study, including familial factors. PMID:23816331

Incidence of childhood pneumonia: facility-based surveillance estimate compared to measured incidence in a South African birth cohort study

PubMed Central

le Roux, David M; Myer, Landon; Nicol, Mark P; Zar, Heather J

2015-01-01

Background Pneumonia is the leading cause of childhood mortality and a major contributor to childhood morbidity, but accurate measurement of pneumonia incidence is challenging. We compared pneumonia incidence using a facility-based surveillance system to estimates from a cohort study conducted contemporaneously in the same community in Cape Town, South Africa. Methods A surveillance system was developed in six public sector primary care clinics and in a regional referral hospital, to detect childhood pneumonia cases. Nurses recorded all children presenting to facilities who met WHO case definitions of pneumonia, and hospital records were reviewed. Estimates of pneumonia incidence and severity were compared with incidence rates based on active surveillance in the Drakenstein Child Health Study. Results From June 2012 until September 2013, the surveillance system detected 306 pneumonia episodes in children under 1 year of age, an incidence of 0.20 episodes/child-year (e/cy) (95% CI 0.17 to 0.22 e/cy). The incidence in the cohort study from the same period was 0.27 e/cy (95% CI 0.23 to 0.32 e/cy). Pneumonia incidence in the surveillance system was almost 30% lower than in the birth cohort; incidence rate ratio 0.72 (95% CI 0.58 to 0.89). In the surveillance system, 18% were severe pneumonia cases, compared to 23% in the birth cohort, rate ratio 0.81 (95% CI 0.55 to 1.18). Conclusions In this setting, facility-based pneumonia surveillance detected fewer cases of pneumonia, and fewer severe cases, compared to the corresponding cohort study. Facility pneumonia surveillance using data collected by local healthcare workers provides a useful estimate of the epidemiology of childhood pneumonia but may underestimate incidence and severity. PMID:26685027

Sharing extended summary data from contemporary genetics studies is unlikely to threaten subject privacy.

PubMed

Bacanu, Silviu-Alin

2017-01-01

Starting from a forensic problem, Homer et al. showed that it was possible to detect if an individual contributes only 0.5% of the DNA in a pool. The finding was extended to prove the possibility of detecting whether a subject participated in a small homogeneous GWAS. We denote this as the detection of a subject belonging to a certain cohort (SBCC). Subsequently, Visscher and Hill showed that the power to detect SBCC signal for an ethnically homogeneous cohort depends roughly on the ratio of the number of independent markers and total sample size. However, it is not clear if the same holds for more ethnically diverse cohorts. Later, Masca et al. propose running as SBCC test a regression of departure from assumed population frequency of i) subject genotype on ii) cohort of interest frequency. They use simulations to show that the approach has better SBCC detection power than the original Homer method but is impeded by population stratification. To investigate the possibility of SBCC detection in multi-ethnic cohorts, we generalize the Masca et al. approach by theoretically deriving the correlation between a subject genotype and the cohort reference allele frequencies (RAFs) for stratified cohorts. Based on the derived formula, we theoretically show that, due to background stratification noise, SBCC detection is unlikely even for mildly stratified cohorts of size greater than around a thousand subjects. Thus, for the vast majority of contemporary cohorts, the fear of compromising privacy via SBCC detection is unfounded.

Socioeconomic Position, Health, and Possible Explanations: A Tale of Two Cohorts

PubMed Central

Fuhrer, R.; Shipley, M. J.; Chastang, J. F.; Schmaus, A.; Niedhammer, I.; Stansfeld, S. A.; Goldberg, M.; Marmot, M. G.

2002-01-01

Objectives. We examined whether the social gradient for measures of morbidity is comparable in English and French public employees and investigated risk factors that may explain this gradient. Methods. This longitudinal study of 2 occupational cohorts—5825 London civil servants and 6818 French office-based employees—used 2 health outcomes: long spells of sickness absence during a 4-year follow-up and self-reported health. Results. Strong social gradients in health were observed in both cohorts. Health behaviors showed different relations with socioeconomic position in the 2 samples. Psychosocial work characteristics showed strong gradients in both cohorts. Cohort-specific significant risk factors explained between 12% and 56% of the gradient in sickness absence and self-reported health. Conclusions. Our cross-cultural comparison suggests that some common susceptibility may underlie the social gradient in health and disease, which explains why inequalities occur in cultures with different patterns of morbidity and mortality. PMID:12144986

Anti-NMDA receptor encephalitis and nonencephalitic HSV-1 infection

PubMed Central

Salovin, Amy; Glanzman, Jason; Roslin, Kylie; Armangue, Thais; Panzer, Jessica A.

2018-01-01

Objective To determine whether there is an association between nonencephalitic herpes simplex virus 1 (HSV-1) infection and anti-NMDA receptor encephalitis (anti-NMDARE). Methods Antibody testing was performed using samples from 2 cohorts in a case-control observational study. The cohort “Philadelphia” included 16 serum samples of pediatric anti-NMDARE cases and 42 age-matched controls with other neuroinflammatory disorders studied at the Children's Hospital of Philadelphia and University of Pennsylvania. The cohort “Barcelona” contained 23 anti-NMDARE patient samples and 26 age-matched participants with other neuroinflammatory disorders studied at IDIBAPS-Hospital Clinic, University of Barcelona. The presence of HSV-1 IgG antibodies was examined by ELISA. As an additional control, IgG antibodies to cytomegalovirus (CMV) and Epstein-Barr virus viral capsid antigen (EBV-VCA) were determined. Results In each cohort, more participants with anti-NMDARE than controls had anti-HSV-1 IgG antibodies. In the Philadelphia cohort (58 participants), 44% of anti-NMDARE cases had antibodies to HSV-1 compared with 14% controls (OR 4.67, 95% CI 1.3–17.3, p = 0.031). In the Barcelona cohort (49 participants), 52% of participants with anti-NMDARE had antibodies to HSV-1 compared with 31% of controls (OR 2.45, 95% CI 0.7–7.9, p = 0.155). Overall, 49% of anti-NMDARE cases have antibodies to HSV-1 in these 2 combined cohorts compared with 21% of controls (Mantel-Haenszel OR 3.21, 95% CI 1.3–7.7, p = 0.007). Conclusion Past HSV-1 infection was found in significantly more anti-NMDARE cases than controls. This suggests a meaningful association between nonencephalitic HSV-1 infection and development of anti-NMDARE. PMID:29629396

Efficacy Evaluation of Current and Future Naval Mine Warfare Neutralization Method

DTIC Science & Technology

2016-12-01

Distribution is unlimited. EFFICACY EVALUATION OF CURRENT AND FUTURE NAVAL MINE WARFARE NEUTRALIZATION METHOD by Team MIW Cohort SE311-152O...EFFICACY EVALUATION OF CURRENT AND FUTURE NAVAL MINE WARFARE NEUTRALIZATION METHOD 5. FUNDING NUMBERS 6. AUTHOR (S) Team MIW, Systems Engineering...NEUTRALIZATION METHOD Team MIW, Systems Engineering Cohort SE311-152O Submitted in partial fulfillment of the requirements for the degrees of

Lessons Learned From Methodological Validation Research in E-Epidemiology

PubMed Central

Assmann, Karen; Andreeva, Valentina; Castetbon, Katia; Méjean, Caroline; Touvier, Mathilde; Salanave, Benoît; Deschamps, Valérie; Péneau, Sandrine; Fezeu, Léopold; Julia, Chantal; Allès, Benjamin; Galan, Pilar; Hercberg, Serge

2016-01-01

Background Traditional epidemiological research methods exhibit limitations leading to high logistics, human, and financial burden. The continued development of innovative digital tools has the potential to overcome many of the existing methodological issues. Nonetheless, Web-based studies remain relatively uncommon, partly due to persistent concerns about validity and generalizability. Objective The objective of this viewpoint is to summarize findings from methodological studies carried out in the NutriNet-Santé study, a French Web-based cohort study. Methods On the basis of the previous findings from the NutriNet-Santé e-cohort (>150,000 participants are currently included), we synthesized e-epidemiological knowledge on sample representativeness, advantageous recruitment strategies, and data quality. Results Overall, the reported findings support the usefulness of Web-based studies in overcoming common methodological deficiencies in epidemiological research, in particular with regard to data quality (eg, the concordance for body mass index [BMI] classification was 93%), reduced social desirability bias, and access to a wide range of participant profiles, including the hard-to-reach subgroups such as young (12.30% [15,118/122,912], <25 years) and old people (6.60% [8112/122,912], ≥65 years), unemployed or homemaker (12.60% [15,487/122,912]), and low educated (38.50% [47,312/122,912]) people. However, some selection bias remained (78.00% (95,871/122,912) of the participants were women, and 61.50% (75,590/122,912) had postsecondary education), which is an inherent aspect of cohort study inclusion; other specific types of bias may also have occurred. Conclusions Given the rapidly growing access to the Internet across social strata, the recruitment of participants with diverse socioeconomic profiles and health risk exposures was highly feasible. Continued efforts concerning the identification of specific biases in e-cohorts and the collection of comprehensive and valid data are still needed. This summary of methodological findings from the NutriNet-Santé cohort may help researchers in the development of the next generation of high-quality Web-based epidemiological studies. PMID:27756715

Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria.

PubMed

Girardoz, S; Tomov, R; Eschen, R; Quicke, D L J; Kenis, M

2007-10-01

The horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miners.

Identifying Vasopressor and Inotrope Use for Health Services Research

PubMed Central

Fawzy, Ashraf; Bradford, Mark; Lindenauer, Peter K.

2016-01-01

Rationale: Identifying vasopressor and inotrope (vasopressor) use from administrative claims data may provide an important resource to study the epidemiology of shock. Objectives: Determine accuracy of identifying vasopressor use using International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) coding. Methods: Using administrative data enriched with pharmacy billing files (Premier, Inc., Charlotte, NC), we identified two cohorts: adult patients admitted with a diagnosis of sepsis from 2010 to 2013 or pulmonary embolism (PE) from 2008 to 2011. Vasopressor administration was obtained using pharmacy billing files (dopamine, dobutamine, epinephrine, milrinone, norepinephrine, phenylephrine, vasopressin) and compared with ICD-9-CM procedure code for vasopressor administration (00.17). We estimated performance characteristics of the ICD-9-CM code and compared patients’ characteristics and mortality rates according to vasopressor identification method. Measurements and Main Results: Using either pharmacy data or the ICD-9-CM procedure code, 29% of 541,144 patients in the sepsis cohort and 5% of 81,588 patients in the PE cohort were identified as receiving a vasopressor. In the sepsis cohort, the ICD-9-CM procedure code had low sensitivity (9.4%; 95% confidence interval, 9.2–9.5), which increased over time. Results were similar in the PE cohort (sensitivity, 5.8%; 95% confidence interval, 5.1–6.6). The ICD-9-CM code exhibited high specificity in the sepsis (99.8%) and PE (100%) cohorts. However, patients identified as receiving vasopressors by ICD-9-CM code had significantly higher unadjusted in-hospital mortality, had more acute organ failures, and were more likely hospitalized in the Northeast and West. Conclusions: The ICD-9-CM procedure code for vasopressor administration has low sensitivity and selects for higher severity of illness in studies of shock. Temporal changes in sensitivity would likely make longitudinal shock surveillance using ICD-9-CM inaccurate. PMID:26653145

English language proficiency, health literacy, and trust in physician are associated with shared decision-making in rheumatoid arthritis

PubMed Central

Barton, Jennifer L.; Trupin, Laura; Tonner, Chris; Imboden, John; Katz, Patricia; Schillinger, Dean; Yelin, Edward H.

2014-01-01

Objective Treat to Target guidelines promote shared decision-making (SDM) in rheumatoid arthritis (RA). Also, due to high cost and potential toxicity of therapies, SDM is central to patient safety. Our objective was to examine patterns of perceived communication around decision-making in two cohorts of adults with RA. Methods Data were derived from patients enrolled in one of two longitudinal, observational cohorts (UCSF RA Cohort and RA Panel). Subjects completed a telephone interview in their preferred language that included a measure of patient-provider communication, including items about decision-making. Measures of trust in physician, education, and language proficiency were also asked. Logistic regression was performed to identify correlates of suboptimal SDM communication. Analyses were performed on each sample separately. Results Of 509 patients across two cohorts, 30% and 32% reported suboptimal SDM communication. Low trust in physician was independently associated with suboptimal SDM communication in both cohorts. Older age and limited English proficiency were independently associated with suboptimal SDM in the UCSF RA Cohort, as was limited health literacy in the RA Panel. Conclusions This study of over 500 adults with RA from two demographically distinct cohorts found that nearly one-third of subjects report suboptimal SDM communication with their clinicians, regardless of cohort. Lower trust in physician was independently associated with suboptimal SDM communication in both cohorts, as was limited English language proficiency and older age in the UCSF RA Cohort and limited health literacy in the Panel. These findings underscore the need to examine the impact of SDM on health outcomes in RA. PMID:24931952

The Nightingale study: rationale, study design and baseline characteristics of a prospective cohort study on shift work and breast cancer risk among nurses.

PubMed

Pijpe, Anouk; Slottje, Pauline; van Pelt, Cres; Stehmann, Floor; Kromhout, Hans; van Leeuwen, Flora E; Vermeulen, Roel C H; Rookus, Matti A

2014-01-29

Evidence for the carcinogenicity of shift work in humans is limited because of significant heterogeneity of the results, thus more in-depth research in needed. The Nightingale Study is a nationwide prospective cohort study on occupational exposures and risks of chronic diseases among female nurses and focuses on the potential association between shift work and risk of breast cancer. The study design, methods, and baseline characteristics of the cohort are described. The source population for the cohort comprised 18 to 65 year old women who were registered as having completed training to be a nurse in the nationwide register for healthcare professionals in the Netherlands. Eligible women were invited to complete a web-based questionnaire including full job history, a detailed section on all domains of shift work (shift system, cumulative exposure, and shift intensity) and potential confounding factors, and an informed consent form for linkage with national (disease) registries. Women were also asked to donate toenail clippings as a source of DNA for genetic analyses. Between October 6, 2011 and February 1, 2012, 31% of the 192,931 women who were invited to participate completed the questionnaire, yielding a sample size of 59,947 cohort members. The mean age of the participants was 46.9 year (standard deviation 11.0 years). Toenail clippings were provided by 23,439 participants (39%). Results from the Nightingale Study will contribute to the scientific evidence of potential shift work-related health risks among nurses and will help develop preventive measures and policy aimed at reducing these risks.

Prognosis of hepatitis C virus-infected Canadian post-transfusion compensation claimant cohort.

PubMed

Thein, H-H; Yi, Q; Heathcote, E J; Krahn, M D

2009-11-01

Accurate prognostic estimates were required to ensure the sufficiency of the $1.1 billion compensation fund established in 1998 to compensate Canadians who acquired hepatitis C virus (HCV) infection through blood transfusion between 1986 and 1990. This article reports the application of Markov modelling and epidemiological methods to estimate the prognosis of individuals who have claimed compensation. Clinical characteristics of the claimant cohort (n = 5004) were used to define the starting distribution. Annual stage-specific transition probabilities (F0-->F1, . . ., F3-->F4) were derived from the claimants, using the Markov maximum likelihood estimation method. HCV treatment efficacy was derived from the literature and practice patterns were estimated from a national survey. The estimated stage-specific transition probabilities of the cohort between F0-->F1, F1-->F2, F2-->F3 and F3-->F4 were 0.032, 0.137, 0.150 and 0.097 respectively. At 20 years after the index transfusion, approximately 10% of all living claimants (n = 3773) had cirrhosis and 0.5% developed hepatocellular carcinoma (HCC). For nonhaemophilic patients, the predicted 20-year (2030) risk of HCV-related cirrhosis was 23%, and the risk of HCC and liver-related death was 7% and 11% respectively. Haemophilic patients who are younger and are frequently co-infected with human immunodeficiency virus would have higher 20-year risks of cirrhosis (37%), HCC (12%) and liver-related death (19%). Our results indicate that rates of progression to advanced liver disease in post-transfusion cohorts may be lower than previously reported. The Canadian post-transfusion cohort offers new and relevant prognostic information for post-transfusion HCV patients in Canada and is an invaluable resource to study the natural history and resource utilization of HCV-infected individuals in future studies.

Years of Potential Life Lost among Heroin Addicts 33 Years after Treatment

PubMed Central

Smyth, Breda; Hoffman, Valerie; Fan, Jing; Hser, Yih-Ing

2007-01-01

Objective To examine premature mortality in terms of years of potential life lost (YPLL) among a cohort of long-term heroin addicts. Method This longitudinal, prospective study followed a cohort of 581 male heroin addicts in California for more than 33 years. In the latest follow-up conducted in 1996/97, 282 subjects (48.5%) were confirmed as deceased by death certificates. YPLL before age 65 years were calculated by causes of death. Ethnic differences in YPLL were assessed among Whites, Hispanics, and African Americans. Results On average, addicts in this cohort lost 18.3 years (SD = 10.7) of potentiallife before age 65. Of the total YPLL for the cohort, 22.3% of the years lost was due to heroin overdose, 14.0% due to chronic liver disease, and 10.2% to accidents. The total YPLL and YPLL by death cause in addict cohort were significant higher than that of US population. The YPLL among African Americans was significantly lower than that among Whites or Hispanics. Conclusion The YPLL among addicts was much higher than that in the national population; within the cohort, premature mortality was higher among Whites and Hispanics compared to African American addicts. PMID:17291577

Determination of mean recency period for estimation of HIV type 1 Incidence with the BED-capture EIA in persons infected with diverse subtypes.

PubMed

Parekh, Bharat S; Hanson, Debra L; Hargrove, John; Branson, Bernard; Green, Timothy; Dobbs, Trudy; Constantine, Niel; Overbaugh, Julie; McDougal, J Steven

2011-03-01

The IgG capture BED enzyme immunoassay (BED-CEIA) was developed to detect recent HIV-1 infection for the estimation of HIV-1 incidence from cross-sectional specimens. The mean time interval between seroconversion and reaching a specified assay cutoff value [referred to here as the mean recency period (ω)], an important parameter for incidence estimation, is determined for some HIV-1 subtypes, but testing in more cohorts and new statistical methods suggest the need for a revised estimation of ω in different subtypes. A total of 2927 longitudinal specimens from 756 persons with incident HIV infections who had been enrolled in 17 cohort studies was tested by the BED-CEIA. The ω was determined using two statistical approaches: (1) linear mixed effects regression (ω(1)) and (2) a nonparametric survival method (ω(2)). Recency periods varied among individuals and by population. At an OD-n cutoff of 0.8, ω(1) was 176 days (95% CL 164-188 days) whereas ω(2) was 162 days (95% CL 152-172 days) when using a comparable subset of specimens (13 cohorts). When method 2 was applied to all available data (17 cohorts), ω(2) ranged from 127 days (Thai AE) to 236 days (subtypes AG, AD) with an overall ω(2) of 197 days (95% CL 173-220). About 70% of individuals reached a threshold OD-n of 0.8 by 197 days (mean ω) and 95% of people reached 0.8 OD-n by 480 days. The determination of ω with more data and new methodology suggests that ω of the BED-CEIA varies between different subtypes and/or populations. These estimates for ω may affect incidence estimates in various studies.

Epidemiology of Infectious Disease–Related Death After Release from Prison, Washington State, United States, and Queensland, Australia: A Cohort Study

PubMed Central

Blatchford, Patrick J.; Forsyth, Simon J.; Stern, Marc F.; Kinner, Stuart A.

2016-01-01

Objectives People in prison may be at high risk for infectious diseases and have an elevated risk of death immediately after release compared with later; their risk of death is elevated for at least a decade after release. We compared rates, characteristics, and prison-related risk factors for infectious disease–related mortality among people released from prisons in Queensland, Australia, and Washington State, United States, regions with analogous available data. Methods We analyzed data from retrospective cohort studies of people released from prison in Queensland (1997–2007, n=37,180) and Washington State (1999–2009, n=76,208) and linked identifiers from each cohort to its respective national death index. We estimated infectious disease–related mortality rates (deaths per person-years in community) and examined associations using Cox proportional hazard models. Results The most frequent infectious disease–related underlying cause of death after release from prison was pneumonia (43%, 23/54 deaths) in the Australian cohort and viral hepatitis (40%, 69/171 deaths) in the U.S. cohort. The infectious disease–related mortality rate was significantly higher in the U.S. cohort than in the Australian cohort (51.2 vs. 26.5 deaths per 100,000 person-years; incidence rate ratio = 1.93, 95% confidence interval 1.42, 2.62). In both cohorts, increasing age was strongly associated with mortality from infectious diseases. Conclusion Differences in the epidemiology of infectious disease–related mortality among people released from prison may reflect differences in patterns of community health service delivery in each region. These findings highlight the importance of preventing and treating hepatitis C and other infectious diseases during the transition from prison to the community. PMID:27453602

Retrospective cohort study of an enhanced recovery programme in oesophageal and gastric cancer surgery

PubMed Central

Gatenby, PAC; Shaw, C; Hine, C; Scholtes, S; Koutra, M; Andrew, H; Hacking, M; Allum, WH

2015-01-01

Introduction Enhanced recovery programmes have been established in some areas of elective surgery. This study applied enhanced recovery principles to elective oesophageal and gastric cancer surgery. Methods An enhanced recovery programme for patients undergoing open oesophagogastrectomy, total and subtotal gastrectomy for oesophageal and gastric malignancy was designed. A retrospective cohort study compared length of stay on the critical care unit (CCU), total length of inpatient stay, rates of complications and in-hospital mortality prior to (35 patients) and following (27 patients) implementation. Results In the cohort study, the median total length of stay was reduced by 3 days following oesophagogastrectomy and total gastrectomy. The median length of stay on the CCU remained the same for all patients. The rates of complications and mortality were the same. Conclusions The standardised protocol reduced the median overall length of stay but did not reduce CCU stay. Enhanced recovery principles can be applied to patients undergoing major oesophagogastrectomy and total gastrectomy as long as they have minimal or reversible co-morbidity. PMID:26414360

Phenotype–genotype spectrum of AAA syndrome from Western India and systematic review of literature

PubMed Central

Patt, Hiren; Koehler, Katrin; Lodha, Sailesh; Yerawar, Chaitanya; Huebner, Angela; Thakkar, Kunal; Arya, Sneha; Nair, Sandhya; Goroshi, Manjunath; Ganesh, Hosahithlu; Sarathi, Vijaya; Lila, Anurag; Bandgar, Tushar; Shah, Nalini

2017-01-01

Objective To study genotype–phenotype spectrum of triple A syndrome (TAS). Methods Retrospective chart analysis of Indian TAS patients (cohort 1, n = 8) and review of genotyped TAS cases reported in world literature (cohort 2, n = 133, 68 publications). Results Median age at presentation was 4.75 years (range: 4–10) and 5 years (range: 1–42) for cohorts 1 and 2, respectively. Alacrima, adrenal insufficiency (AI), achalasia and neurological dysfunction (ND) were seen in 8/8, 8/8, 7/8 and 4/8 patients in cohort 1, and in 99, 91, 93 and 79% patients in cohort 2, respectively. In both cohorts, alacrima was present since birth while AI and achalasia manifested before ND. Mineralocorticoid deficiency (MC) was uncommon (absent in cohort 1, 12.5% in cohort 2). In cohort 1, splice-site mutation in exon 1 (p.G14Vfs*45) was commonest, followed by a deletion in exon 8 (p.S255Vfs*36). Out of 65 mutations in cohort 2, 14 were recurrent and five exhibited regional clustering. AI was more prevalent, more often a presenting feature, and was diagnosed at younger age in T group (those with truncating mutations) as compared to NT (non-truncating mutations) group. ND was more prevalent, more common a presenting feature, with later age at onset in NT as compared to T group. Conclusion Clinical profile of our patients is similar to that of patients worldwide. Alacrima is the earliest and most consistent finding. MC deficiency is uncommon. Some recurrent mutations show regional clustering. p.G14Vfs*45 and p.S255Vfs*36 account for majority of AAAS mutations in our cohort. Phenotype of T group differs from that of NT group and merits future research. PMID:29180348

ESTIMATION OF INTERNAL EXPOSURE TO URANIUM WITH UNCERTAINTY FROM URINALYSIS DATA USING THE InDEP COMPUTER CODE

PubMed Central

Anderson, Jeri L.; Apostoaei, A. Iulian; Thomas, Brian A.

2015-01-01

The National Institute for Occupational Safety and Health (NIOSH) is currently studying mortality in a cohort of 6409 workers at a former uranium processing facility. As part of this study, over 220 000 urine samples were used to reconstruct organ doses due to internal exposure to uranium. Most of the available computational programs designed for analysis of bioassay data handle a single case at a time, and thus require a significant outlay of time and resources for the exposure assessment of a large cohort. NIOSH is currently supporting the development of a computer program, InDEP (Internal Dose Evaluation Program), to facilitate internal radiation exposure assessment as part of epidemiological studies of both uranium- and plutonium-exposed cohorts. A novel feature of InDEP is its batch processing capability which allows for the evaluation of multiple study subjects simultaneously. InDEP analyses bioassay data and derives intakes and organ doses with uncertainty estimates using least-squares regression techniques or using the Bayes’ Theorem as applied to internal dosimetry (Bayesian method). This paper describes the application of the current version of InDEP to formulate assumptions about the characteristics of exposure at the study facility that were used in a detailed retrospective intake and organ dose assessment of the cohort. PMID:22683620

Young adult conservation jobs and worker health

Treesearch

Kathleen L. Wolf; Elizabeth Housley

2017-01-01

Decades of research studies demonstrate links between healthy environment, healthy lifestyles, and healthy people. This study evaluated the correlations between young adult conservation workers’ perceived stress, personal effectiveness, and nature experience using quantitative and qualitative social science methods. The study cohort numbered nearly 300 individuals...

The Forgotten Learning Disability – Epidemiology of Written Language Disorder in a Population-Based Birth Cohort (1976-1982), Rochester, Minnesota

PubMed Central

Katusic, Slavica K.; Colligan, Robert C.; Weaver, Amy L.; Barbaresi, William J.

2009-01-01

OBJECTIVE The aim of this study was to report the incidence rates and other epidemiologic characterizations of Written Language Disorder (WLD). There have been no epidemiologic studies on the incidence of WLD in the United States and the use of a population-based birth cohort, longitudinally followed, is the most powerful method to reach this objective. METHODS In this population-based, retrospective birth cohort study, subjects included 5718 children born 1976-1982 in Rochester, Minnesota who remained in the community after age 5 years. Records from all public and nonpublic schools, medical facilities, and private tutorial services were reviewed and results of all individually administered IQ and achievement tests, and extensive medical, educational, and socioeconomic information were collected. The essential features of writing problems from the DSM-IV-TR were included in our operationalized definition of WLD. WLD incident cases were established using research criteria based on 3 formulas (regression-based discrepancy, non-regression-based discrepancy, low achievement). RESULTS Cumulative incidence rates of WLD varied from 6.9% to 14.7% depending on the formula. Boys were 2-3 times more likely to be affected than girls, regardless of the formula. Among all WLD cases (N=806), 25% (N=203) had WLD without Reading Disability (RD). Specifics of the writing problems were identified for 87% (N=702) of WLD cases. CONCLUSION In this population-based birth cohort of school aged children, WLD was at least as frequent as RD, and significantly more frequent among boys than girls. PMID:19403496

Rationale, design and methods for the 22 year follow-up of the Western Australian Pregnancy Cohort (Raine) Study.

PubMed

Straker, Leon M; Hall, Graham L; Mountain, Jenny; Howie, Erin K; White, Elisha; McArdle, Nigel; Eastwood, Peter R

2015-07-14

Young adulthood is a critical life period for health and health behaviours. Related measurements collected before and after birth, and during childhood and adolescence can provide a life-course analysis of important factors that contribute to health and behaviour in young adulthood. The Western Australian Pregnancy Cohort (Raine) Study has collected a large number of such measurements during the fetal, perinatal, infancy, childhood and adolescence periods and plans to relate them to common health issues and behaviours in young adults, including spinal pain, asthma, sleep disorders, physical activity and sedentary behaviour and, work absenteeism and presenteeism. The aim of this paper is to describe the rationale, design and methods of the 22 year follow-up of the Raine Study cohort. The Raine Study is a prospective cohort study. Participants still active in the cohort (n = 2,086) were contacted around the time of their 22nd birthday and invited to participate in the 22 year follow-up. Each was asked to complete a questionnaire, attend a research facility for physical assessment and an overnight sleep study, wear activity monitors for a week, and to maintain a sleep and activity diary over this week. The questionnaire was broad and included questions related to sociodemographics, medical history, quality of life, psychological factors, lifestyle factors, spinal pain, respiratory, sleep, activity and work factors. Physical assessments included anthropometry, blood pressure, back muscle endurance, tissue sensitivity, lung function, airway reactivity, allergic status, 3D facial photographs, cognitive function, and overnight polysomnography. Describing the prevalence of these health issues and behaviours in young adulthood will enable better recognition of the issues and planning of health care resources. Providing a detailed description of the phenotype of these issues will provide valuable information to help educate health professionals of the needs of young adults. Understanding the life-course risk factors of health issues and behaviours in young adulthood will have important health planning implications, supporting the development of targeted interventions to improve current health status and reduce the onset and development of further ill-health across adulthood.

Non-replication of the association between 5HTTLPR and response to psychological therapy for child anxiety disorders

PubMed Central

Lester, Kathryn J.; Roberts, Susanna; Keers, Robert; Coleman, Jonathan R. I.; Breen, Gerome; Wong, Chloe C. Y.; Xu, Xiaohui; Arendt, Kristian; Blatter-Meunier, Judith; Bögels, Susan; Cooper, Peter; Creswell, Cathy; Heiervang, Einar R.; Herren, Chantal; Hogendoorn, Sanne M.; Hudson, Jennifer L.; Krause, Karen; Lyneham, Heidi J.; McKinnon, Anna; Morris, Talia; Nauta, Maaike H.; Rapee, Ronald M.; Rey, Yasmin; Schneider, Silvia; Schneider, Sophie C.; Silverman, Wendy K.; Smith, Patrick; Thastum, Mikael; Thirlwall, Kerstin; Waite, Polly; Wergeland, Gro Janne; Eley, Thalia C.

2016-01-01

Background We previously reported an association between 5HTTLPR genotype and outcome following cognitive–behavioural therapy (CBT) in child anxiety (Cohort 1). Children homozygous for the low-expression short-allele showed more positive outcomes. Other similar studies have produced mixed results, with most reporting no association between genotype and CBT outcome. Aims To replicate the association between 5HTTLPR and CBT outcome in child anxiety from the Genes for Treatment study (GxT Cohort 2, n = 829). Method Logistic and linear mixed effects models were used to examine the relationship between 5HTTLPR and CBT outcomes. Mega-analyses using both cohorts were performed. Results There was no significant effect of 5HTTLPR on CBT outcomes in Cohort 2. Mega-analyses identified a significant association between 5HTTLPR and remission from all anxiety disorders at follow-up (odds ratio 0.45, P = 0.014), but not primary anxiety disorder outcomes. Conclusions The association between 5HTTLPR genotype and CBT outcome did not replicate. Short-allele homozygotes showed more positive treatment outcomes, but with small, non-significant effects. Future studies would benefit from utilising whole genome approaches and large, homogenous samples. PMID:26294368

The Link between Potassium and Mild Cognitive Impairment in Mexican-Americans

PubMed Central

Vintimilla, Raul M.; Large, Stephanie E.; Gamboa, Adriana; Rohlfing, Geoffrey D.; O'Jile, Judith R.; Hall, James R.; O'Bryant, Sid E.; Johnson, Leigh A.

2018-01-01

Background Recent evidence suggests that increasing dietary intake of minerals reduces the risk of dementia. This study aimed to examine the relationship between potassium and diagnosis of mild cognitive impairment (MCI) in a sample of older Mexican-Americans from rural and urban populations. Methods The sample was formed of a total of 139 participants with MCI and 371 normal controls from two independent cohorts: a rural cohort (Facing Rural Obstacles to Healthcare Now through Intervention, Education and Research [Project FRONTIER]) and an urban cohort (the Health and Aging Brain among Latino Elders [HABLE] study). Serum electrolytes examined were sodium and potassium. Age and education were entered in the model as covariates. Results Across both cohorts, the Project FRONTIER (OR = 3.1; p = 0.01) and the HABLE Project (OR = 2.0; p = 0.04), the results indicated that serum potassium levels significantly increased the risk of diagnosis of MCI. Conclusion Our finding suggested a link between serum potassium levels and a diagnosis of MCI in Mexican-Americans. The results of this study support a previous research which has suggested that the risk factors for MCI may vary by ethnicity. PMID:29805381

Longitudinal Intergenerational Birth Cohort Designs: A Systematic Review of Australian and New Zealand Studies

PubMed Central

Townsend, Michelle L.; Riepsamen, Angelique; Georgiou, Christos; Flood, Victoria M.; Caputi, Peter; Wright, Ian M.; Davis, Warren S.; Jones, Alison; Larkin, Theresa A.; Williamson, Moira J.; Grenyer, Brin F. S.

2016-01-01

Background The longitudinal birth cohort design has yielded a substantial contribution to knowledge of child health and development. The last full review in New Zealand and Australia in 2004 identified 13 studies. Since then, birth cohort designs continue to be an important tool in understanding how intrauterine, infant and childhood development affect long-term health and well-being. This updated review in a defined geographical area was conducted to better understand the factors associated with successful quality and productivity, and greater scientific and policy contribution and scope. Methods We adopted the preferred reporting items for systematic reviews and meta-analyses (PRISMA) approach, searching PubMed, Scopus, Cinahl, Medline, Science Direct and ProQuest between 1963 and 2013. Experts were consulted regarding further studies. Five inclusion criteria were used: (1) have longitudinally tracked a birth cohort, (2) have collected data on the child and at least one parent or caregiver (3) be based in Australia or New Zealand, (4) be empirical in design, and (5) have been published in English. Results 10665 records were initially retrieved from which 23 birth cohort studies met the selection criteria. Together these studies recruited 91,196 participants, with 38,600 mothers, 14,206 fathers and 38,390 live births. Seventeen studies were located in Australia and six in New Zealand. Research questions initially focused on the perinatal period, but as studies matured, longer-term effects and outcomes were examined. Conclusions This review demonstrates the significant yield from this effort both in terms of scientific discovery and social policy impact. Further opportunities have been recognised with cross-study collaboration and pooling of data between established and newer studies and international studies to investigate global health determinants. PMID:26991330

An exploratory study of the perceived impact of health problems of landmine/UXO victims versus another disability group

PubMed Central

2012-01-01

Background The purpose of this exploratory study is to pilot a biopsychosocial instrument called the Perceived Impact of Problem Profile (PIPP) on a cohort of landmine/Unexploded Ordnance (UXO) victims with lower limb disability versus a cohort of persons with similar disability due to other trauma or medical causes. The aim is to provide greater understanding of the psychosocial impact of landmine/UXO injury to inform victim assistance a interventions within Lao PDR. Methods This study employs a mixed methods design, which involved piloting the PIPP instrument through an interviewer administered questionnaire and demographic questionnaire. Fifty one participants were interviewed in both urban and rural locations within Lao PDR. Results An analysis of the data reveals significant differences in perceived impact for pain, anxiety and how recently the injury/illness occurred. Both groups complained of high levels of anxiety and depression; landmine/UXO victims who complained of anxiety and depression reported a much greater impact on life satisfaction and mood. Conclusion The perceived impact of the disability is greatest on psychosocial factors for both cohorts, but especially in landmine/UXO victims emphasising the need to focus on improving psychosocial interventions for landmine/UXO victims within Victim assistance programmes in Lao PDR. PMID:23016958

PubMed Central

Marchand, R.

1993-01-01

Three recent articles are examined in which research using the double-blind randomised clinical trial, the case control study, and the quasi-cohort study is described. Understanding the advantages and disadvantages of these methods makes it easier to grasp the pneumococcal vaccine controversy and make an informed choice. PMID:8499794

Early postoperative magnet application combined with hydrocolloid dressing for the treatment of earlobe keloids.

PubMed

Park, Tae Hwan; Chang, Choong Hyun

2013-04-01

To prevent the recurrence of earlobe keloids after surgical removal, a reliable and safe postoperative treatment method is critical. To the authors' knowledge, no studies have elucidated the most effective postoperative dressing method for preventing the recurrence of earlobe keloids. This study aimed to compare keloid recurrence rates in patients whose keloids were dressed using conventional methods (plain gauze or a polyvinyl alcohol sponge) with those of a matched cohort of patients whose keloids were dressed using magnets combined with hydrocolloid materials. This observational case-control study compared a retrospective cohort of patients whose keloids were dressed using conventional methods with a matched prospective cohort of patients whose keloids were dressed using magnets combined with hydrocolloid materials. The study included patients with pathologically confirmed earlobe keloids that were surgically excised with primary closure. Patients 8 years of age or older underwent adjuvant pressure therapy with magnets at the study hospital. Patients were excluded from the study if they were unavailable for follow-up evaluation, if they had received additional adjuvant therapy during treatment, or if histologic confirmation of a keloid was not obtained. Matched-pair analysis was performed using the McNemar test. Treatment outcome was evaluated as recurrence or nonrecurrence. Overall, 9 (11.2%) of the 80 study patients experienced recurrence. The recurrence rate was significantly lower in the matched case group (2 of 40, 5%) than in the matched control group (7 of 40, 17.5%) during the follow-up period of 18 months (p=0.0253). The authors' novel dressing of magnets and hydrocolloid materials appears to be effective in reducing earlobe keloid recurrence. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A comparative study of machine learning methods for time-to-event survival data for radiomics risk modelling.

PubMed

Leger, Stefan; Zwanenburg, Alex; Pilz, Karoline; Lohaus, Fabian; Linge, Annett; Zöphel, Klaus; Kotzerke, Jörg; Schreiber, Andreas; Tinhofer, Inge; Budach, Volker; Sak, Ali; Stuschke, Martin; Balermpas, Panagiotis; Rödel, Claus; Ganswindt, Ute; Belka, Claus; Pigorsch, Steffi; Combs, Stephanie E; Mönnich, David; Zips, Daniel; Krause, Mechthild; Baumann, Michael; Troost, Esther G C; Löck, Steffen; Richter, Christian

2017-10-16

Radiomics applies machine learning algorithms to quantitative imaging data to characterise the tumour phenotype and predict clinical outcome. For the development of radiomics risk models, a variety of different algorithms is available and it is not clear which one gives optimal results. Therefore, we assessed the performance of 11 machine learning algorithms combined with 12 feature selection methods by the concordance index (C-Index), to predict loco-regional tumour control (LRC) and overall survival for patients with head and neck squamous cell carcinoma. The considered algorithms are able to deal with continuous time-to-event survival data. Feature selection and model building were performed on a multicentre cohort (213 patients) and validated using an independent cohort (80 patients). We found several combinations of machine learning algorithms and feature selection methods which achieve similar results, e.g. C-Index = 0.71 and BT-COX: C-Index = 0.70 in combination with Spearman feature selection. Using the best performing models, patients were stratified into groups of low and high risk of recurrence. Significant differences in LRC were obtained between both groups on the validation cohort. Based on the presented analysis, we identified a subset of algorithms which should be considered in future radiomics studies to develop stable and clinically relevant predictive models for time-to-event endpoints.

Prevalence and cost of hospital medical errors in the general and elderly United States populations.

PubMed

Mallow, Peter J; Pandya, Bhavik; Horblyuk, Ruslan; Kaplan, Harold S

2013-12-01

The primary objective of this study was to quantify the differences in the prevalence rate and costs of hospital medical errors between the general population and an elderly population aged ≥65 years. Methods from an actuarial study of medical errors were modified to identify medical errors in the Premier Hospital Database using data from 2009. Visits with more than four medical errors were removed from the population to avoid over-estimation of cost. Prevalence rates were calculated based on the total number of inpatient visits. There were 3,466,596 total inpatient visits in 2009. Of these, 1,230,836 (36%) occurred in people aged ≥ 65. The prevalence rate was 49 medical errors per 1000 inpatient visits in the general cohort and 79 medical errors per 1000 inpatient visits for the elderly cohort. The top 10 medical errors accounted for more than 80% of the total in the general cohort and the 65+ cohort. The most costly medical error for the general population was postoperative infection ($569,287,000). Pressure ulcers were most costly ($347,166,257) in the elderly population. This study was conducted with a hospital administrative database, and assumptions were necessary to identify medical errors in the database. Further, there was no method to identify errors of omission or misdiagnoses within the database. This study indicates that prevalence of hospital medical errors for the elderly is greater than the general population and the associated cost of medical errors in the elderly population is quite substantial. Hospitals which further focus their attention on medical errors in the elderly population may see a significant reduction in costs due to medical errors as a disproportionate percentage of medical errors occur in this age group.

Systemic effects of low-dose dopamine during administration of cytarabine.

PubMed

Connelly, James; Benani, Dina J; Newman, Matthew; Burton, Bradley; Crow, Jessica; Levis, Mark

2017-09-01

Purpose Low-dose dopamine has been utilized to improve renal blood flow, urine output, and reduce drug-induced nephrotoxicity. The purpose of this study was to assess changes in renal function, cardiovascular adverse events, and neurologic toxicity in patients receiving cytarabine with or without low-dose dopamine. Methods A retrospective, single-center, cohort study of patients receiving cytarabine at 667 mg/m 2 /dose or greater, with or without dopamine at ≤5 mcg/kg/min. Cohorts were based upon initiation or absence of low-dose dopamine; cytarabine only, cytarabine + pre- and day of low-dose dopamine, and cytarabine + post-low-dose dopamine. Renal outcomes (urine output, serum creatinine, and creatinine clearance) were compared with baseline and between cohorts. Safety endpoints (arrhythmias, tachycardia, and neurotoxicity) were compared between cohorts based on low-dose dopamine exposure. Results There was no difference in urine output from baseline in all cohorts. Comparing cytarabine only and pre- and day of low-dose dopamine cohorts, there was no difference in urine output. In those receiving low-dose dopamine, there was no difference in serum creatinine and creatinine clearance from baseline. No arrhythmias were documented during the study period, and there was no difference in the incidence of tachycardia between groups (P = 0.66). Neurotoxicity was reported in three patients who were on low-dose dopamine. Conclusion Though variation existed in individual patients administered low-dose dopamine, the use of low-dose dopamine did not significantly impact renal function in this small sample at a single institution. In addition, low-dose dopamine did not negatively impact cardiovascular function.

Laparoscopic skills acquisition: a study of simulation and traditional training.

PubMed

Marlow, Nicholas; Altree, Meryl; Babidge, Wendy; Field, John; Hewett, Peter; Maddern, Guy J

2014-12-01

Training in basic laparoscopic skills can be undertaken using traditional methods, where trainees are educated by experienced surgeons through a process of graduated responsibility or by simulation-based training. This study aimed to assess whether simulation trained individuals reach the same level of proficiency in basic laparoscopic skills as traditional trained participants when assessed in a simulated environment. A prospective study was undertaken. Participants were allocated to one of two cohorts according to surgical experience. Participants from the inexperienced cohort were randomized to receive training in basic laparoscopic skills on either a box trainer or a virtual reality simulator. They were then assessed on the simulator on which they did not receive training. Participants from the experienced cohort, considered to have received traditional training in basic laparoscopic skills, did not receive simulation training and were randomized to either the box trainer or virtual reality simulator for skills assessment. The assessment scores from different cohorts on either simulator were then compared. A total of 138 participants completed the assessment session, 101 in the inexperienced simulation-trained cohort and 37 on the experienced traditionally trained cohort. There was no statistically significant difference between the training outcomes of simulation and traditionally trained participants, irrespective of the simulator type used. The results demonstrated that participants trained on either a box trainer or virtual reality simulator achieved a level of basic laparoscopic skills assessed in a simulated environment that was not significantly different from participants who had been traditionally trained in basic laparoscopic skills. © 2013 Royal Australasian College of Surgeons.

The Northern Norway mother-and-child contaminant cohort study: implementation, population characteristics and summary of dietary findings

PubMed Central

Veyhe, Anna Sofía; Hansen, Solrunn; Sandanger, Torkjel M.; Nieboer, Evert; Odland, Jon Øyvind

2012-01-01

Objectives To describe the essential features of a new Northern Norway mother-and-child contaminant cohort study called MISA, including its rationale, content, implementation and selected findings (mostly dietary). Study design Cross-sectional with longitudinal aspects. Methods Five hundred and fifteen eligible women were enrolled in early pregnancy, with 391 completing the study protocol that included a self-administrated food frequency questionnaire (FFQ) and donation of biological samples for contaminant analysis in the 2nd trimester, just after delivery, and 6 weeks postpartum. Macronutrient consumption was converted to energy intake, and the amounts of both macro- and micronutrients ingested were estimated. Some of the MISA findings were compared to data available in the Medical Birth Registry of Norway (MBRN). Results Compared to all 2004–2006 mothers in Northern Norway, the study cohort women were about 2 years older and smoked less; on average, they had close to 16 years of education. Parity, gestational age and birth weight of the newborn were comparable as well. The estimated average dietary intake of 8.1 MJ per day was less than that recommended by the Nordic Nutritional Recommendations (NNR), but the intake of micronutrients per MJ complied. Conclusions Although the final cohort sample size was less than targeted, the generally good comparisons observed between MBRN-registered information for the study cohort and dropouts suggest that this occurrence introduced minimal bias. The agreement of the observed demographic and clinical characteristics of the cohort women and newborns with all births in Northern Norway implied acceptable external validity. Also, the dietary findings aligned well with Norwegian national data and guidelines and other studies, as did the high prevalence of breastfeeding. The MISA database is considered suitable for exploring associations between contaminant exposure and diet, enhancing our knowledge of the interplay of the physiological changes that occur in mothers with contaminant pharmacokinetics (including transfer to the infant before and after birth), and conducting prospective health studies of the children. PMID:22957315

Influence function based variance estimation and missing data issues in case-cohort studies.

PubMed

Mark, S D; Katki, H

2001-12-01

Recognizing that the efficiency in relative risk estimation for the Cox proportional hazards model is largely constrained by the total number of cases, Prentice (1986) proposed the case-cohort design in which covariates are measured on all cases and on a random sample of the cohort. Subsequent to Prentice, other methods of estimation and sampling have been proposed for these designs. We formalize an approach to variance estimation suggested by Barlow (1994), and derive a robust variance estimator based on the influence function. We consider the applicability of the variance estimator to all the proposed case-cohort estimators, and derive the influence function when known sampling probabilities in the estimators are replaced by observed sampling fractions. We discuss the modifications required when cases are missing covariate information. The missingness may occur by chance, and be completely at random; or may occur as part of the sampling design, and depend upon other observed covariates. We provide an adaptation of S-plus code that allows estimating influence function variances in the presence of such missing covariates. Using examples from our current case-cohort studies on esophageal and gastric cancer, we illustrate how our results our useful in solving design and analytic issues that arise in practice.

Negative Control Outcomes and the Analysis of Standardized Mortality Ratios

PubMed Central

Richardson, DB; Keil, A; Tchetgen, Tchetgen E; Cooper, GS

2016-01-01

In occupational cohort mortality studies, epidemiologists often compare the observed number of deaths in the cohort to the expected number obtained by multiplying person-time accrued in the study cohort by the mortality rate in an external reference population. Interpretation of the result may be difficult due to non-comparability of the occupational cohort and reference population. We describe an approach to estimate an adjusted standardized mortality ratio (aSMR) to control for bias due to unmeasured differences between the occupational cohort and the reference population. The approach draws on methods developed for the use of negative control outcomes. Conditions necessary for unbiased estimation are described, as well as looser conditions necessary for bias reduction. The approach is illustrated using data on bladder cancer mortality among male Oak Ridge National Laboratory workers. The SMR for bladder cancer was elevated among hourly-paid males (SMR=1.90; 1.27, 2.72) but not among monthly-paid males (SMR=0.96; 0.67, 1.33). After indirect adjustment using the proposed approach, the mortality ratios were similar in magnitude among hourly- and monthly-paid men (aSMR=2.22; 1.52, 3.24; and, aSMR=1.99; 1.43, 2.76, respectively). The proposed adjusted SMR offers a complement to typical standardized mortality ratio analyses. PMID:26172862

The international primary ciliary dyskinesia cohort (iPCD Cohort): methods and first results.

PubMed

Goutaki, Myrofora; Maurer, Elisabeth; Halbeisen, Florian S; Amirav, Israel; Barbato, Angelo; Behan, Laura; Boon, Mieke; Casaulta, Carmen; Clement, Annick; Crowley, Suzanne; Haarman, Eric; Hogg, Claire; Karadag, Bulent; Koerner-Rettberg, Cordula; Leigh, Margaret W; Loebinger, Michael R; Mazurek, Henryk; Morgan, Lucy; Nielsen, Kim G; Omran, Heymut; Schwerk, Nicolaus; Scigliano, Sergio; Werner, Claudius; Yiallouros, Panayiotis; Zivkovic, Zorica; Lucas, Jane S; Kuehni, Claudia E

2017-01-01

Data on primary ciliary dyskinesia (PCD) epidemiology is scarce and published studies are characterised by low numbers. In the framework of the European Union project BESTCILIA we aimed to combine all available datasets in a retrospective international PCD cohort (iPCD Cohort).We identified eligible datasets by performing a systematic review of published studies containing clinical information on PCD, and by contacting members of past and current European Respiratory Society Task Forces on PCD. We compared the contents of the datasets, clarified definitions and pooled them in a standardised format.As of April 2016 the iPCD Cohort includes data on 3013 patients from 18 countries. It includes data on diagnostic evaluations, symptoms, lung function, growth and treatments. Longitudinal data are currently available for 542 patients. The extent of clinical details per patient varies between centres. More than 50% of patients have a definite PCD diagnosis based on recent guidelines. Children aged 10-19 years are the largest age group, followed by younger children (≤9 years) and young adults (20-29 years).This is the largest observational PCD dataset available to date. It will allow us to answer pertinent questions on clinical phenotype, disease severity, prognosis and effect of treatments, and to investigate genotype-phenotype correlations. Copyright ©ERS 2017.

The international primary ciliary dyskinesia cohort (iPCD Cohort): methods and first results

PubMed Central

Goutaki, Myrofora; Maurer, Elisabeth; Halbeisen, Florian S.; Amirav, Israel; Barbato, Angelo; Behan, Laura; Boon, Mieke; Casaulta, Carmen; Clement, Annick; Crowley, Suzanne; Haarman, Eric; Hogg, Claire; Karadag, Bulent; Koerner-Rettberg, Cordula; Leigh, Margaret W.; Loebinger, Michael R.; Mazurek, Henryk; Morgan, Lucy; Nielsen, Kim G.; Omran, Heymut; Schwerk, Nicolaus; Scigliano, Sergio; Werner, Claudius; Yiallouros, Panayiotis; Zivkovic, Zorica; Lucas, Jane S.

2017-01-01

Data on primary ciliary dyskinesia (PCD) epidemiology is scarce and published studies are characterised by low numbers. In the framework of the European Union project BESTCILIA we aimed to combine all available datasets in a retrospective international PCD cohort (iPCD Cohort). We identified eligible datasets by performing a systematic review of published studies containing clinical information on PCD, and by contacting members of past and current European Respiratory Society Task Forces on PCD. We compared the contents of the datasets, clarified definitions and pooled them in a standardised format. As of April 2016 the iPCD Cohort includes data on 3013 patients from 18 countries. It includes data on diagnostic evaluations, symptoms, lung function, growth and treatments. Longitudinal data are currently available for 542 patients. The extent of clinical details per patient varies between centres. More than 50% of patients have a definite PCD diagnosis based on recent guidelines. Children aged 10–19 years are the largest age group, followed by younger children (≤9 years) and young adults (20–29 years). This is the largest observational PCD dataset available to date. It will allow us to answer pertinent questions on clinical phenotype, disease severity, prognosis and effect of treatments, and to investigate genotype–phenotype correlations. PMID:28052956

Age-Based Methods to Explore Time-Related Variables in Occupational Epidemiology Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janice P. Watkins, Edward L. Frome, Donna L. Cragle

2005-08-31

Although age is recognized as the strongest predictor of mortality in chronic disease epidemiology, a calendar-based approach is often employed when evaluating time-related variables. An age-based analysis file, created by determining the value of each time-dependent variable for each age that a cohort member is followed, provides a clear definition of age at exposure and allows development of diverse analytic models. To demonstrate methods, the relationship between cancer mortality and external radiation was analyzed with Poisson regression for 14,095 Oak Ridge National Laboratory workers. Based on previous analysis of this cohort, a model with ten-year lagged cumulative radiation doses partitionedmore » by receipt before (dose-young) or after (dose-old) age 45 was examined. Dose-response estimates were similar to calendar-year-based results with elevated risk for dose-old, but not when film badge readings were weekly before 1957. Complementary results showed increasing risk with older hire ages and earlier birth cohorts, since workers hired after age 45 were born before 1915, and dose-young and dose-old were distributed differently by birth cohorts. Risks were generally higher for smokingrelated than non-smoking-related cancers. It was difficult to single out specific variables associated with elevated cancer mortality because of: (1) birth cohort differences in hire age and mortality experience completeness, and (2) time-period differences in working conditions, dose potential, and exposure assessment. This research demonstrated the utility and versatility of the age-based approach.« less

Outcomes of Zika virus infection during pregnancy: contributions to the debate on the efficiency of cohort studies.

PubMed

Duarte, Elisabeth Carmen; Garcia, Leila Posenato; de Araújo, Wildo Navegantes; Velez, Maria P

2017-12-02

Zika infection during pregnancy (ZIKVP) is known to be associated with adverse outcomes. Studies on this matter involve both rare outcomes and rare exposures and methodological choices are not straightforward. Cohort studies will surely offer more robust evidences, but their efficiency must be enhanced. We aim to contribute to the debate on sample selection strategies in cohort studies to assess outcomes associated with ZKVP. A study can be statistically more efficient than another if its estimates are more accurate (precise and valid), even if the studies involve the same number of subjects. Sample size and specific design strategies can enhance or impair the statistical efficiency of a study, depending on how the subjects are distributed in subgroups pertinent to the analysis. In most ZIKVP cohort studies to date there is an a priori identification of the source population (pregnant women, regardless of their exposure status) which is then sampled or included in its entirety (census). Subsequently, the group of pregnant women is classified according to exposure (presence or absence of ZIKVP), respecting the exposed:unexposed ratio in the source population. We propose that the sample selection be done from the a priori identification of groups of pregnant women exposed and unexposed to ZIKVP. This method will allow for an oversampling (even 100%) of the pregnant women with ZKVP and a optimized sampling from the general population of pregnant women unexposed to ZIKVP, saving resources in the unexposed group and improving the expected number of incident cases (outcomes) overall. We hope that this proposal will broaden the methodological debate on the improvement of statistical power and protocol harmonization of cohort studies that aim to evaluate the association between Zika infection during pregnancy and outcomes for the offspring, as well as those with similar objectives.

Hepatitis E Seroprevalence in Europe: A Meta-Analysis

PubMed Central

Hartl, Johannes; Otto, Benjamin; Madden, Richie Guy; Webb, Glynn; Woolson, Kathy Louise; Kriston, Levente; Vettorazzi, Eik; Lohse, Ansgar W.; Dalton, Harry Richard; Pischke, Sven

2016-01-01

There have been large numbers of studies on anti-HEV IgG seroprevalence in Europe, however, the results of these studies have produced high variability of seroprevalence rates, making interpretation increasingly problematic. Therefore, the aim of this study was to develop a clearer understanding of anti-HEV IgG seroprevalence in Europe and identify risk groups for HEV exposure by a meta-analysis of published studies. Methods: All European HEV-seroprevalence studies from 2003 to 2015 were reviewed. Data were stratified by assay, geographical location, and patient cohort (general population, patients with HIV, solid-organ transplant recipients, chronic liver disease patients, and individuals in contact with swine/wild animals). Data were pooled using a mixed-effects model. Results: Four hundred thirty-two studies were initially identified, of which 73 studies were included in the analysis. Seroprevalence estimates ranged from 0.6% to 52.5%, increased with age, but were unrelated to gender. General population seroprevalence varied depending on assays: Wantai (WT): 17%, Mikrogen (MG): 10%, MP-diagnostics (MP): 7%, DiaPro: 4%, Abbott 2%. The WT assay reported significantly higher seroprevalence rates across all cohorts (p < 0.001). Individuals in contact with swine/wild animals had significantly higher seroprevalence rates than the general population, irrespective of assay (p < 0.0001). There was no difference between any other cohorts. The highest seroprevalence was observed in France (WT: 32%, MP: 16%) the lowest in Italy (WT: 7.5%, MP 0.9%). Seroprevalence varied between and within countries. The observed heterogeneity was attributed to geographical region (23%), assay employed (23%) and study cohort (7%). Conclusion: Seroprevalcence rates primarily depend on the seroassy that is used, followed by the geographical region and study cohort. Seroprevalence is higher in individuals exposed to swine and/or wild animals, and increases with age. PMID:27509518

Maternal blood contamination of collected cord blood can be identified using DNA methylation at three CpGs.

PubMed

Morin, Alexander M; Gatev, Evan; McEwen, Lisa M; MacIsaac, Julia L; Lin, David T S; Koen, Nastassja; Czamara, Darina; Räikkönen, Katri; Zar, Heather J; Koenen, Karestan; Stein, Dan J; Kobor, Michael S; Jones, Meaghan J

2017-01-01

Cord blood is a commonly used tissue in environmental, genetic, and epigenetic population studies due to its ready availability and potential to inform on a sensitive period of human development. However, the introduction of maternal blood during labor or cross-contamination during sample collection may complicate downstream analyses. After discovering maternal contamination of cord blood in a cohort study of 150 neonates using Illumina 450K DNA methylation (DNAm) data, we used a combination of linear regression and random forest machine learning to create a DNAm-based screening method. We identified a panel of DNAm sites that could discriminate between contaminated and non-contaminated samples, then designed pyrosequencing assays to pre-screen DNA prior to being assayed on an array. Maternal contamination of cord blood was initially identified by unusual X chromosome DNA methylation patterns in 17 males. We utilized our DNAm panel to detect contaminated male samples and a proportional amount of female samples in the same cohort. We validated our DNAm screening method on an additional 189 sample cohort using both pyrosequencing and DNAm arrays, as well as 9 publically available cord blood 450K data sets. The rate of contamination varied from 0 to 10% within these studies, likely related to collection specific methods. Maternal blood can contaminate cord blood during sample collection at appreciable levels across multiple studies. We have identified a panel of markers that can be used to identify this contamination, either post hoc after DNAm arrays have been completed, or in advance using a targeted technique like pyrosequencing.

Dynamic Measurement of Disease Activity in Acute Pancreatitis: The Pancreatitis Activity Scoring System

PubMed Central

Wu, Bechien U.; Batech, Michael; Quezada, Michael; Lew, Daniel; Fujikawa, Kelly; Kung, Jonathan; Jamil, Laith H.; Chen, Wansu; Afghani, Elham; Reicher, Sonya; Buxbaum, James; Pandol, Stephen J.

2017-01-01

OBJECTIVES Acute pancreatitis has a highly variable course. Currently there is no widely accepted method to measure disease activity in patients hospitalized for acute pancreatitis. We aimed to develop a clinical activity index that incorporates routine clinical parameters to assist in the measurement, study, and management of acute pancreatitis. METHODS We used the UCLA/RAND appropriateness method to identify items for inclusion in the disease activity instrument. We conducted a systematic literature review followed by two sets of iterative modified Delphi meetings including a panel of international experts between November 2014 and November 2015. The final instrument was then applied to patient data obtained from five separate study cohorts across Southern California to assess profiles of disease activity. RESULTS From a list of 35 items comprising 6 domains, we identified 5 parameters for inclusion in the final weighted clinical activity scoring system: organ failure, systemic inflammatory response syndrome, abdominal pain, requirement for opiates and ability to tolerate oral intake. We applied the weighted scoring system across the 5 study cohorts comprising 3,123 patients. We identified several distinct patterns of disease activity: (i) overall there was an elevated score at baseline relative to discharge across all study cohorts, (ii) there were distinct patterns of disease activity related to duration of illness as well as (iii) early and persistent elevation of disease activity among patients with severe acute pancreatitis defined as persistent organ failure. CONCLUSIONS We present the development and initial validation of a clinical activity score for real-time assessment of disease activity in patients with acute pancreatitis. PMID:28462914

Rational case management of malaria with a rapid diagnostic test, Paracheck Pf®, in antenatal health care in Bangui, Central African Republic

PubMed Central

2012-01-01

Background Both treatment and prevention strategies are recommended by the World Health Organization for the control of malaria during pregnancy in tropical areas. The aim of this study was to assess use of a rapid diagnostic test for prompt management of malaria in pregnancy in Bangui, Central African Republic. Methods A cohort of 76 pregnant women was screened systematically for malaria with ParacheckPf® at each antenatal visit. The usefulness of the method was analysed by comparing the number of malaria episodes requiring treatment in the cohort with the number of prescriptions received by another group of pregnant women followed-up in routine antenatal care. Results In the cohort group, the proportion of positive ParacheckPf® episodes during antenatal clinics visits was 13.8%, while episodes of antimalarial prescriptions in the group which was followed-up routinely by antenatal personnel was estimated at 26.3%. Hence, the relative risk of the cohort for being prescribed an antimalarial drug was 0.53. Therefore, the attributable fraction of presumptive treatment avoided by systematic screening with ParacheckPf® was 47%. Conclusions Use of a rapid diagnostic test is useful, affordable and easy for adequate treatment of malaria in pregnant women. More powerful studies of the usefulness of introducing the test into antenatal care are needed in all heath centres in the country and in other tropical areas. PMID:22734602

Mortality among Japanese construction workers in Mie Prefecture

PubMed Central

Sun, J; Kubota, H; Hisanaga, N; Shibata, E; Kamijima, M; Nakamura, K

2002-01-01

Aims: A historical cohort mortality study was conducted among 17 668 members of the Construction Workers' Health Insurance Society of Mie Prefecture in Japan, in order to verify the relation between occupations and mortality status. Methods: The cohort was followed from 2 April 1973 to 1 April 1998. Standardised mortality ratios (SMR) were calculated for all members and each job classification. Results: 98.7% of the members were traced successfully until the date when the follow up terminated. When all members were considered together, significant excess mortality was observed for "accidents and adverse effects". Significant excess mortalities were also observed for lung cancers among scaffold men and ironworkers, for cancer of the oesophagus among plumbers, and for "chronic liver disease and cirrhosis" among scaffold men and painters. Conclusion: Results suggest that more detailed investigations, which would include some minor job classifications should be undertaken. This is an updated cohort study which was partially completed in 1997. PMID:12151606

Online and Offline Recruitment of Young Women for a Longitudinal Health Survey: Findings From the Australian Longitudinal Study on Women’s Health 1989-95 Cohort

PubMed Central

Powers, Jennifer; Anderson, Amy E; Townsend, Natalie; Harris, Melissa L; Tuckerman, Ryan; Pease, Stephanie; Mishra, Gita; Byles, Julie

2015-01-01

Background In 2012, we set out to recruit a cohort of at least 10,000 women aged 18-23 from across Australia. With recent research demonstrating the inadequacy of traditional approaches to recruiting women in this age group, we elected to conduct open recruiting. Objective Our aim was to report on the overall success of open recruiting and to evaluate the relative success of a variety of recruitment methods in terms of numbers and demographics. Methods We used referrals, Facebook, formal advertising, and incentives in order to recruit the cohort. Results In all, 17,069 women were recruited for the longitudinal online survey, from 54,685 initiated surveys. Of these women, most (69.94%, n=11,799) who joined the longitudinal cohort were recruited via Facebook, 12.72% (n=2145) via the fashion promotion, 7.02% (n=1184) by referral, 4.9% (n=831) via other Web activities, and 5.4% (n=910) via traditional media. Conclusions Facebook was by far the most successful strategy, enrolling a cohort of women with a similar profile to the population of Australian women in terms of age, area of residence, and relationship status. Women recruited via fashion promotion were the least representative. All strategies underrepresented less educated women—a finding that is consistent with more traditional means of recruiting. In conclusion, flexibility in recruitment design, embracing new and traditional media, adopting a dynamic responsive approach, and monitoring the results of recruiting in terms of sample composition and number recruited led to the successful establishment of a new cohort. PMID:25940876

Lean body mass: the development and validation of prediction equations in healthy adults

PubMed Central

2013-01-01

Background There is a loss of lean body mass (LBM) with increasing age. A low LBM has been associated with increased adverse effects from prescribed medications such as chemotherapy. Accurate assessment of LBM may allow for more accurate drug prescribing. The aims of this study were to develop new prediction equations (PEs) for LBM with anthropometric and biochemical variables from a development cohort and then validate the best performing PEs in validation cohorts. Methods PEs were developed in a cohort of 188 healthy subjects and then validated in a convenience cohort of 52 healthy subjects. The best performing anthropometric PE was then compared to published anthropometric PEs in an older (age ≥ 50 years) cohort of 2287 people. Best subset regression analysis was used to derive PEs. Correlation, Bland-Altman and Sheiner & Beal methods were used to validate and compare the PEs against dual X-ray absorptiometry (DXA)-derived LBM. Results The PE which included biochemistry variables performed only marginally better than the anthropometric PE. The anthropometric PE on average over-estimated LBM by 0.74 kg in the combined cohort. Across gender (male vs. female), body mass index (< 22, 22- < 27, 27- < 30 and ≥30 kg/m2) and age groups (50–64, 65–79 and ≥80 years), the maximum mean over-estimation of the anthropometric PE was 1.36 kg. Conclusions A new anthropometric PE has been developed that offers an alternative for clinicians when access to DXA is limited. Further research is required to determine the clinical utility and if it will improve the safety of medication use. PMID:24499708

Associations of Glycemic Index and Load With Coronary Heart Disease Events: A Systematic Review and Meta-Analysis of Prospective Cohorts

PubMed Central

Mirrahimi, Arash; de Souza, Russell J.; Chiavaroli, Laura; Sievenpiper, John L.; Beyene, Joseph; Hanley, Anthony J.; Augustin, Livia S. A.; Kendall, Cyril W. C.; Jenkins, David J. A.

2012-01-01

Background Glycemic index (GI) and glycemic load (GL) have been associated with coronary heart disease (CHD) risk in some but not all cohort studies. We therefore assessed the association of GI and GL with CHD risk in prospective cohorts. Methods and Results We searched MEDLINE, EMBASE, and CINAHL (through April 5, 2012) and identified all prospective cohorts assessing associations of GI and GL with incidence of CHD. Meta-analysis of observational studies in epidemiology (MOOSE) methodologies were used. Relative measures of risk, comparing the group with the highest exposure (mean GI of cohorts=84.4 GI units, range 79.9 to 91; mean GL of cohorts=224.8, range 166 to 270) to the reference group (mean GI=72.3 GI units, range 68.1 to 77; mean GL=135.4, range 83 to 176), were pooled using random-effects models, expressed as relative risk (RR) with heterogeneity assessed by χ2 and quantified by I2. Subgroups included sex and duration of follow-up. Ten studies (n=240 936) were eligible. Pooled analyses showed an increase in CHD risk for the highest GI quantile compared with the lowest, with RR=1.11 (95% confidence interval [CI] 0.99 to 1.24) and for GL, RR=1.27 (95% CI 1.09 to 1.49), both with evidence of heterogeneity (I2>42%, P<0.07). Subgroup analyses revealed only a significant modification by sex, with the female cohorts showing significance for GI RR=1.26 (95% CI 1.12 to 1.41) and for GL RR=1.55 (95% CI 1.18 to 2.03). Conclusions High GI and GL diets were significantly associated with CHD events in women but not in men. Further studies are required to determine the relationship between GI and GL with CHD in men. PMID:23316283

Physical and cultural determinants of postpartum pelvic floor support and symptoms following vaginal delivery: a protocol for a mixed-methods prospective cohort study

PubMed Central

Nygaard, Ingrid E; Clark, Erin; Clark, Lauren; Egger, Marlene J; Hitchcock, Robert; Hsu, Yvonne; Norton, Peggy; Sanchez-Birkhead, Ana; Shaw, Janet; Sheng, Xiaoming; Varner, Michael

2017-01-01

Introduction Pelvic floor disorders (PFDs), including pelvic organ prolapse (POP), stress and urgency urinary incontinence, and faecal incontinence, are common and arise from loss of pelvic support. Although severe disease often does not occur until women become older, pregnancy and childbirth are major risk factors for PFDs, especially POP. We understand little about modifiable factors that impact pelvic floor function recovery after vaginal birth. This National Institutes of Health (NIH)-funded Program Project, ‘Bridging physical and cultural determinants of postpartum pelvic floor support and symptoms following vaginal delivery’, uses mixed-methods research to study the influences of intra-abdominal pressure, physical activity, body habitus and muscle fitness on pelvic floor support and symptoms as well as the cultural context in which women experience those changes. Methods and analysis Using quantitative methods, we will evaluate whether pelvic floor support and symptoms 1 year after the first vaginal delivery are affected by biologically plausible factors that may impact muscle, nerve and connective tissue healing during recovery (first 8 weeks postpartum) and strengthening (remainder of the first postpartum year). Using qualitative methods, we will examine cultural aspects of perceptions, explanations of changes in pelvic floor support, and actions taken by Mexican-American and Euro-American primipara, emphasising early changes after childbirth. We will summarise project results in a resource toolkit that will enhance opportunities for dialogue between women, their families and providers, and across lay and medical discourses. We anticipate enrolling up to 1530 nulliparous women into the prospective cohort study during the third trimester, following those who deliver vaginally 1 year postpartum. Participants will be drawn from this cohort to meet the project's aims. Ethics and dissemination The University of Utah and Intermountain Healthcare Institutional Review Boards approved this study. Data are stored in a secure password-protected database. Papers summarising the primary results and ancillary analyses will be published in peer-reviewed journals. PMID:28073797

Examining the Impact of a Video Case-Based Mathematics Methods Course on Secondary Pre-Service Teachers' Skills at Analysing Students' Strategies

ERIC Educational Resources Information Center

Martinez, Mara Vanina; Superfine, Alison Castro; Carlton, Theresa; Dasgupta, Chandan

2015-01-01

This paper focuses on results from a study conducted with two cohorts of pre-service teachers (PSTs) in a video case-based mathematics methods course at a large Midwestern university in the US. The motivation for this study was to look beyond whether or not PSTs pay attention to mathematical thinking of students, as shown by previous studies when…

The Shozu Herpes Zoster (SHEZ) Study: Rationale, Design, and Description of a Prospective Cohort Study

PubMed Central

Takao, Yukiko; Miyazaki, Yoshiyuki; Onishi, Fumitake; Kumihashi, Hideaki; Gomi, Yasuyuki; Ishikawa, Toyokazu; Okuno, Yoshinobu; Mori, Yasuko; Asada, Hideo; Yamanishi, Koichi; Iso, Hiroyasu

2012-01-01

Background The incidence and risk factors for herpes zoster have been studied in cross-sectional and cohort studies, although most such studies have been conducted in Western countries. Evidence from Asian populations is limited, and no cohort study has been conducted in Asia. We are conducting a 3-year prospective cohort study in Shozu County in Kagawa Prefecture, Japan to determine the incidence and predictive and immunologic factors for herpes zoster among Japanese. Methods The participants are followed for 3 years, and a telephone survey is conducted every 4 weeks. The participants were assigned to 1 of 3 studies. Participants in study A gave information on past history of herpes zoster and completed health questionnaires. Study B participants additionally underwent varicella-zoster virus (VZV) skin testing, and study C participants additionally underwent blood testing. If the participants develop herpes zoster, we evaluate clinical symptoms, measure cell-mediated immunity and humoral immunity using venous blood sampling, photograph skin areas with rash, conduct virus identification testing by polymerase chain reaction (PCR) and virus isolation from crust sampling, and evaluate postherpetic pain. Results We recruited 12 522 participants aged 50 years or older in Shozu County from December 2009 through November 2010. The participation rate was 65.7% of the target population. Conclusions The present study is likely to provide valuable data on the incidence and predictive and immunologic factors for herpes zoster in a defined community-based population of Japanese. PMID:22343323

Suicide Method Runs in Families: A Birth Certificate Cohort Study of Adolescent Suicide in Taiwan

ERIC Educational Resources Information Center

Lu, Tsung-Hsueh; Chang, Wan-Ting; Lin, Jin-Jia; Li, Chung-Yi

2011-01-01

Suicide method used by adolescents was examined to determine if it was the same as that employed by their suicidal parents. Six hundred eighty adolescents completed suicide between 1997 and 2007, of whom 12 had parents who had previously died by suicide. The suicide method used by these adolescents was compared with that employed by their suicidal…

A Genome-Wide Association Study of Chronic Obstructive Pulmonary Disease in Hispanics

PubMed Central

Chen, Wei; Brehm, John M.; Manichaikul, Ani; Cho, Michael H.; Boutaoui, Nadia; Yan, Qi; Burkart, Kristin M.; Enright, Paul L.; Rotter, Jerome I.; Petersen, Hans; Leng, Shuguang; Obeidat, Ma’en; Bossé, Yohan; Brandsma, Corry-Anke; Hao, Ke; Rich, Stephen S.; Powell, Rhea; Avila, Lydiana; Soto-Quiros, Manuel; Silverman, Edwin K.; Tesfaigzi, Yohannes; Barr, R. Graham

2015-01-01

Rationale: Genome-wide association studies (GWAS) of chronic obstructive pulmonary disease (COPD) have identified disease-susceptibility loci, mostly in subjects of European descent. Objectives: We hypothesized that by studying Hispanic populations we would be able to identify unique loci that contribute to COPD pathogenesis in Hispanics but remain undetected in GWAS of non-Hispanic populations. Methods: We conducted a metaanalysis of two GWAS of COPD in independent cohorts of Hispanics in Costa Rica and the United States (Multi-Ethnic Study of Atherosclerosis [MESA]). We performed a replication study of the top single-nucleotide polymorphisms in an independent Hispanic cohort in New Mexico (the Lovelace Smokers Cohort). We also attempted to replicate prior findings from genome-wide studies in non-Hispanic populations in Hispanic cohorts. Measurements and Main Results: We found no genome-wide significant association with COPD in our metaanalysis of Costa Rica and MESA. After combining the top results from this metaanalysis with those from our replication study in the Lovelace Smokers Cohort, we identified two single-nucleotide polymorphisms approaching genome-wide significance for an association with COPD. The first (rs858249, combined P value = 6.1 × 10−8) is near the genes KLHL7 and NUPL2 on chromosome 7. The second (rs286499, combined P value = 8.4 × 10−8) is located in an intron of DLG2. The two most significant single-nucleotide polymorphisms in FAM13A from a previous genome-wide study in non-Hispanics were associated with COPD in Hispanics. Conclusions: We have identified two novel loci (in or near the genes KLHL7/NUPL2 and DLG2) that may play a role in COPD pathogenesis in Hispanic populations. PMID:25584925

Multicenter cohort association study of SLC2A1 single nucleotide polymorphisms and age-related macular degeneration

PubMed Central

Baas, Dominique C.; Ho, Lintje; Tanck, Michael W.T.; Fritsche, Lars G.; Merriam, Joanna E.; van het Slot, Ruben; Koeleman, Bobby P.C.; Gorgels, Theo G.M.F.; van Duijn, Cornelia M.; Uitterlinden, André G.; de Jong, Paulus T.V.M.; Hofman, Albert; ten Brink, Jacoline B.; Vingerling, Johannes R.; Klaver, Caroline C.W.; Dean, Michael; Weber, Bernhard H. F.; Allikmets, Rando; Hageman, Gregory S.

2012-01-01

Purpose Age-related macular degeneration (AMD) is a major cause of blindness in older adults and has a genetically complex background. This study examines the potential association between single nucleotide polymorphisms (SNPs) in the glucose transporter 1 (SLC2A1) gene and AMD. SLC2A1 regulates the bioavailability of glucose in the retinal pigment epithelium (RPE), which might influence oxidative stress–mediated AMD pathology. Methods Twenty-two SNPs spanning the SLC2A1 gene were genotyped in 375 cases and 199 controls from an initial discovery cohort (the Amsterdam-Rotterdam-Netherlands study). Replication testing was performed in The Rotterdam Study (the Netherlands) and study populations from Würzburg (Germany), the Age Related Eye Disease Study (AREDS; United States), Columbia University (United States), and Iowa University (United States). Subsequently, a meta-analysis of SNP association was performed. Results In the discovery cohort, significant genotypic association between three SNPs (rs3754219, rs4660687, and rs841853) and AMD was found. Replication in five large independent (Caucasian) cohorts (4,860 cases and 4,004 controls) did not yield consistent association results. The genotype frequencies for these SNPs were significantly different for the controls and/or cases among the six individual populations. Meta-analysis revealed significant heterogeneity of effect between the studies. Conclusions No overall association between SLC2A1 SNPs and AMD was demonstrated. Since the genotype frequencies for the three SLC2A1 SNPs were significantly different for the controls and/or cases between the six cohorts, this study corroborates previous evidence that population dependent genetic risk heterogeneity in AMD exists. PMID:22509097

A Systematic Review of Intervention Studies Examining Nutritional and Herbal Therapies for Mild Cognitive Impairment and Dementia Using Neuroimaging Methods: Study Characteristics and Intervention Efficacy

PubMed Central

MacMillan, Freya; Camfield, David A.; Seto, Sai W.

2017-01-01

Neuroimaging facilitates the assessment of complementary medicines (CMs) by providing a noninvasive insight into their mechanisms of action in the human brain. This is important for identifying the potential treatment options for target disease cohorts with complex pathophysiologies. The aim of this systematic review was to evaluate study characteristics, intervention efficacy, and the structural and functional neuroimaging methods used in research assessing nutritional and herbal medicines for mild cognitive impairment (MCI) and dementia. Six databases were searched for articles reporting on CMs, dementia, and neuroimaging methods. Data were extracted from 21/2,742 eligible full text articles and risk of bias was assessed. Nine studies examined people with Alzheimer's disease, 7 MCI, 4 vascular dementia, and 1 all-cause dementia. Ten studies tested herbal medicines, 8 vitamins and supplements, and 3 nootropics. Ten studies used electroencephalography (EEG), 5 structural magnetic resonance imaging (MRI), 2 functional MRI (fMRI), 3 cerebral blood flow (CBF), 1 single photon emission tomography (SPECT), and 1 positron emission tomography (PET). Four studies had a low risk of bias, with the majority consistently demonstrating inadequate reporting on randomisation, allocation concealment, blinding, and power calculations. A narrative synthesis approach was assumed due to heterogeneity in study methods, interventions, target cohorts, and quality. Eleven key recommendations are suggested to advance future work in this area. PMID:28303161

Exploratory cohort study and meta-analysis of BIM deletion polymorphism in patients with epidermal growth factor receptor-mutant non-small-cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors

PubMed Central

Sun, Si; Yu, Hui; Wang, Huijie; Zhao, Xinmin; Zhao, Xintai; Wu, Xianghua; Qiao, Jie; Chang, Jianhua; Wang, Jialei

2017-01-01

Background Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations might develop primary and secondary resistance to tyrosine kinase inhibitors (TKIs). The proapoptotic protein Bcl-2-like 11 (BIM) is a key modulator of apoptosis triggered by EGFR-TKIs. The recent studies have indicated that some patients with positive EGFR mutations were refractory to EGFR-TKIs if they harbored a BIM deletion polymorphism. The purpose of this study was to investigate whether BIM polymorphism predicts treatment efficacy of EGFR-TKIs in Chinese NSCLC patients. Patients and methods A cohort of advanced NSCLC patients with EGFR mutations and treated with EGFR-TKIs (gefitinib or erlotinib) were recruited. We drew peripheral blood to determinate BIM deletion status and then compared patients’ clinical outcomes according to the BIM deletion status. Additionally, we electronically searched eligible cohort studies and conducted a meta-analysis to pool event risk. Results The exploratory cohort study included 140 patients. Patients with and without the BIM deletion polymorphism had similar objective response rates (ORRs, 48.5 vs 63.0%, P=0.16), disease control rate (DCR, 93.9 vs 97.0%, P=0.60) and adverse reactions. Similar progression-free survival (PFS) and overall survival (OS) were noted in overall population (P=0.27 for PFS and P=0.61 for OS) and prespecified patient subgroups. The meta-analysis included 10 eligible cohort studies involving 1,317 NSCLC patients. It showed the positive BIM deletion was associated with shorter PFS (hazard ratio =1.45; P=0.02). Nonsignificant differences existed for ORR, DCR and OS. Conclusion The expanded meta-analysis results demonstrated the positive BIM deletion predicts shorter PFS in NSCLC patients after treatment with EGFR-TKIs while other clinical measures do not. A large multicenter well-designed cohort study involving other concurrent genetic alterations is warranted. PMID:28435285

GFR at Initiation of Dialysis and Mortality in CKD: A Meta-analysis

PubMed Central

Susantitaphong, Paweena; Altamimi, Sarah; Ashkar, Motaz; Balk, Ethan M.; Stel, Vianda S.; Wright, Seth; Jaber, Bertrand L.

2012-01-01

Background The proportion of patients with advanced chronic kidney disease (CKD) initiating dialysis at higher glomerular filtration rate (GFR) has increased over the past decade. Recent data suggest that higher GFR may be associated with increased mortality. Study Design A meta-analysis of cohort studies and trials. Setting & Population Patients with advanced CKD. Selection Criteria for Studies We performed a systematic literature search in MEDLINE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, American Society of Nephrology abstracts, and bibliographies of retrieved articles to identify studies reporting on GFR at dialysis initiation and mortality. Predictor estimated or calculated GFR at dialysis initiation. Outcome Pooled adjusted hazard ratio (HR) of continuous GFR for all-cause mortality. Results Sixteen cohort studies and one randomized controlled trial were identified (n=1,081,116). By meta-analysis, restricted to the 15 cohorts (n=1,079,917), higher GFR at dialysis initiation was associated with a higher pooled adjusted HR for all-cause mortality (1.04; 95% CI, 1.03–1.05; P<0.001). However, there was significant heterogeneity (I2=97%; P<0.001). The association persisted among the 9 cohorts that adjusted analytically for nutritional covariates (HR 1.03; 95% CI 1.02, 1.04; P<0.001; residual I2=97%). The highest mortality risk was observed in hemodialysis cohorts (HR 1.05; 95% CI 1.02, 1.08; P<0.001) whereas there was no association between GFR and mortality in peritoneal dialysis cohorts (HR 1.04; 95% CI 0.99, 1.08, P=0.11; residual I2=98%). Finally, higher GFR was associated with a lower mortality risk in cohorts that calculated GFR (HR 0.80; 95% CI 0.71, 0.91; P=0.003), contrasting with a higher mortality risk in cohorts that estimated GFR (HR 1.04; 95% CI 1.03, 1.05; P<0.001; residual I2=97%). Limitations Paucity of randomized controlled trials; different methods for determining GFR; and substantial heterogeneity. Conclusions Higher estimated rather than calculated GFR at dialysis initiation is associated with a higher mortality risk among patients with advanced CKD, independent of nutritional status. Although there was substantial heterogeneity of effect size estimates across studies, this observation requires further study. PMID:22465328

Air pollution, airway inflammation and lung function in Mexico City school children

EPA Science Inventory

BACKGROUND: The biological mechanisms involved in inflammatory response to air pollution are not clearly understood. OBJECTIVE: In this study we assessed the association of short-term air pollutant exposure with inflammatory markers and lung function. METHODS: We studied a cohort...

MORTALITY AMONG PARTICIPANTS IN THE AGRICULTURAL HEALTH STUDY

EPA Science Inventory

Purpose: This analysis of the Agricultural Health Study cohort assesses the mortality experience of licensed pesticide applicators and their spouses.

Methods: This report is based on 52,393 private applicators (who are mostly farmers) and 32,345 spouses of farmers in Iowa...

Disease burden of chronic hepatitis B among immigrants in Canada

PubMed Central

Wong, William WL; Woo, Gloria; Heathcote, E Jenny; Krahn, Murray

2013-01-01

BACKGROUND: The prevalence of chronic hepatitis B (CHB) infection among immigrants to North America ranges from 2% to 15%, 40% of whom develop advanced liver disease. Screening for hepatitis B surface antigen is not recommended for immigrants. OBJECTIVE: To estimate the disease burden of CHB among immigrants in Canada using Markov cohort models comparing a cohort of immigrants with CHB versus a control cohort of immigrants without CHB. METHODS: Markov cohort models were used to estimate life years, quality-adjusted life years and lifetime direct medical costs (adjusted to 2008 Canadian dollars) for a cohort of immigrants with CHB living in Canada in 2006, and an age-matched control cohort of immigrants without CHB living in Canada in 2006. Parameter values were derived from the published literature. RESULTS: At the baseline estimate, the model suggested that the cohort of immigrants with CHB lost an average of 4.6 life years (corresponding to 1.5 quality-adjusted life years), had an increased average of $24,249 for lifetime direct medical costs, and had a higher lifetime risk for decompensated cirrhosis (12%), hepatocellular carcinoma (16%) and need for liver transplant (5%) when compared with the control cohort. DISCUSSION: Results of the present study showed that the socio-economic burden of CHB among immigrants living in Canada is sub-stantial. Governments and health systems need to develop policies that promote early recognition of CHB and raise public awareness regarding hepatitis B to extend the lives of infected immigrants. PMID:23516678

Age-period-cohort analysis of suicides among Japanese 1950-2003: a Bayesian cohort model analysis.

PubMed

Ooe, Yosuke; Ohno, Yuko; Nakamura, Takashi

2009-07-01

The suicide rate in Japan is one of the highest in the world and presents us with a considerable challenge. Demographic statistics show that the number of suicides is on the rise, and at roughly 30,000 people per year have committed suicide since 1998. Suicide trends are not only related to economic boom and bust but also to certain generations and age groups. During the 1950s, there was a remarkably high suicide rate among people in their 20s, and this cohort was identical to that of the middle-age generation in the 1980s. It is important to separately understand both the trend of suicide rates and the numbers analyzed to determine the different factors that influence suicide. These include age, time period, cohort, interaction between age and time period, and changes in population composition. We performed an age-period-cohort analysis of annual trends of suicide rates by age group in Japan using a Bayesian cohort model. With the help of the Nakamura method, we have been able to break down the effects of age, time period, cohort, and the age-by-period interaction. The cohort comprised of people born in the 1930s demonstrated a relatively high suicide rate. Men currently in their 50s also belong to a high suicide rate cohort. Regarding the period effect, business cycles and by-period interaction effect, it became apparent that the high suicide rate among young adults in their early 20s around 1960 was slowing, especially among men. Instead, there was an obvious recent trend for men in their late 50s to have the highest suicide rate. This study confirmed that age-period-cohort analysis can describe these trends of suicide mortality of the Japanese.

Internal and external generalizability of temporal dose-response relationships for xerostomia following IMRT for head and neck cancer

PubMed Central

Thor, Maria; Owosho, Adepitan A; Clark, Haley D; Oh, Jung Hun; Riaz, Nadeem; Hovan, Allan; Tsai, Jillian; Thomas, Steven D; Yom, Sae Hee K; Wu, Jonn S; Huryn, Joseph M; Moiseenko, Vitali; Lee, Nancy Y; Estilo, Cherry L; Deasy, Joseph O

2016-01-01

Background and Purpose To study internal and external generalizability of temporal dose-response relationships for xerostomia after intensity-modulated radiotherapy (IMRT) for head and neck cancer, and to investigate potential amendments of the QUANTEC guidelines. Material and Methods Objective xerostomia was assessed in 121 patients (nCohort1=55; nCohort2=66) treated to 70Gy@2Gy in 2006–2015. Univariate and multivariate analyses (UVA, MVA with 1000 bootstrap populations) were conducted in Cohort1, and generalizability of the best-performing MVA model was investigated in Cohort2 (performance: AUC, p-values, and Hosmer-Lemeshow p-values (pHL)). Ultimately and for clinical guidance, minimum mean dose thresholds to the contralateral and the ipsilateral parotid glands (Dmeancontra, Dmeanipsi) were estimated from the generated dose-response curves. Results The observed xerostomia rate was 38%/47% (3 months) and 19%/23% (11–12 months) in Cohort1/Cohort2. Risk of xerostomia at 3 months increased for higher Dmeancontra and Dmeanipsi (Cohort1: 0.17•Dmeancontra+0.11•Dmeanipsi−8.13; AUC=0.90±0.05; p=0.0002±0.002; pHL=0.22±0.23; Cohort2: AUC=0.81; p<0.0001; pHL=0.27). The identified minimum Dmeancontra thresholds were lower than in the QUANTEC guidelines (Cohort1/Cohort2: Dmeancontra=12/19 Gy; Dmeancontra, Dmeanipsi=16, 25/20, 26 Gy). Conclusions Increased Dmeancontra and Dmeanipsi explain short-term xerostomia following IMRT. Our results also suggest decreasing Dmeancontra to below 20 Gy, while keeping Dmeanipsi to around 25 Gy. Long-term xerostomia was less frequent, and no dose-response relationship was established for this follow-up time. PMID:27890427

Graft Diameter as a Predictor for Revision Anterior Cruciate Ligament Reconstruction and KOOS and EQ-5D Values: A Cohort Study From the Swedish National Knee Ligament Register Based on 2240 Patients.

PubMed

Snaebjörnsson, Thorkell; Hamrin Senorski, Eric; Ayeni, Olufemi R; Alentorn-Geli, Eduard; Krupic, Ferid; Norberg, Fredrik; Karlsson, Jón; Samuelsson, Kristian

2017-07-01

Anterior cruciate ligament (ACL) reconstruction (ACLR) using a hamstring tendon (HT) autograft is an effective and widespread method. Recent studies have identified a relationship between the graft diameter and revision ACLR. To evaluate the influence of the graft diameter on revision ACLR and patient-reported outcomes in patients undergoing primary ACLR using HT autografts. Cohort study; Level of evidence, 2. A prospective cohort study was conducted using the Swedish National Knee Ligament Register (SNKLR) involving all patients undergoing primary ACLR using HT autografts. Patients with graft failure who needed revision surgery (cases) were compared with patients not undergoing revision surgery (controls). The control group was matched for sex, age, and graft fixation method in a 3:1 ratio. Conditional logistic regression was performed to produce odds ratios and 95% CIs. Univariate linear regression analyses were performed for patient-related outcomes. The Knee injury and Osteoarthritis Outcome Score (KOOS) and EuroQol 5 dimensions questionnaire (EQ-5D) values were obtained. A total of 2240 patients were included in which there were 560 cases and 1680 controls. No significant differences between the cases and controls were found for sex (52.9% male), mean age (21.7 years), and femoral and tibial fixation. The mean graft diameter for the cases was 8.0 ± 0.74 mm and for the controls was 8.1 ± 0.76 mm. In the present cohort, the likelihood of revision surgery for every 0.5-mm increase in the HT autograft diameter between 7.0 and 10.0 mm was 0.86 (95% CI, 0.75-0.99; P = .03). Univariate linear regression analysis found no significant regression coefficient for the change in KOOS or EQ-5D values. In a large cohort of patients after primary ACLR with HT autografts, an increase in the graft diameter between 7.0 and 10.0 mm resulted in a 0.86 times lower likelihood of revision surgery with every 0.5-mm increase. This study provides further evidence of the importance of the HT autograft size in intraoperative decision making.

The All Our Babies pregnancy cohort: design, methods, and participant characteristics

PubMed Central

2013-01-01

Background The prospective cohort study design is ideal for examining diseases of public health importance, as its inherent temporal nature renders it advantageous for studying early life influences on health outcomes and research questions of aetiological significance. This paper will describe the development and characteristics of the All Our Babies (AOB) study, a prospective pregnancy cohort in Calgary, Alberta, Canada designed to examine determinants of maternal, infant, and child outcomes and identify barriers and facilitators in health care utilization. Methods Women were recruited from health care offices, communities, and through Calgary Laboratory Services before 25 weeks gestation from May 2008 to December 2010. Participants completed two questionnaires during pregnancy, a third at 4 months postpartum, and are currently being followed-up with questionnaires at 12, 24, and 36 months. Data was collected on pregnancy history, demographics, lifestyle, health care utilization, physical and mental health, parenting, and child developmental outcomes and milestones. In addition, biological/serological and genetic markers can be extracted from collected maternal and cord blood samples. Results A total of 4011 pregnant women were eligible for recruitment into the AOB study. Of this, 3388 women completed at least one survey. The majority of participants were less than 35 years of age, Caucasian, Canadian born, married or in a common-law relationship, well-educated, and reported household incomes above the Calgary median. Women who discontinued after the first survey (n=123) were typically younger, non-Caucasian, foreign-born, had lower education and household income levels, were less likely to be married or in a common-law relationship, and had poor psychosocial health in early pregnancy. In general, AOB participants reflect the pregnant and parenting population at local and provincial levels, and perinatal indicators from the study are comparable to perinatal surveillance data. Conclusions The extensive and rich data collected in the AOB cohort provides the opportunity to answer complex questions about the relationships between biology, early experiences, and developmental outcomes. This cohort will contribute to the understanding of the biologic mechanisms and social/environmental pathways underlying associations between early and later life outcomes, gene-environment interactions, and developmental trajectories among children. PMID:23445747

The costs of fluid overload in the adult intensive care unit: is a small-volume infusion model a proactive solution?

PubMed Central

Child, Debra L; Cao, Zhun; Seiberlich, Laura E; Brown, Harold; Greenberg, Jordan; Swanson, Anne; Sewall, Martha R; Robinson, Scott B

2015-01-01

Purpose Fluid overload (FO) in critically ill patients remains a challenging clinical dilemma, and many continuous intravenous (IV) medications in the US are being delivered as a dilute solution, adding significantly to a patient’s daily intake. This study describes the costs and outcomes of FO in patients receiving multiple continuous infusions. Materials and methods A retrospective study was conducted using a hospital administrative database covering >500 US hospitals. An FO cohort included adult intensive care unit (ICU) patients with a central line receiving IV loop diuretics and 2+ continuous IV infusions on 50%+ of their ICU days; a directly matched non-FO cohort included patients without IV diuretic use. The primary outcome of the study was total hospitalization costs per visit. Additional outcomes were ICU costs, mortality, total and ICU length of stay (LOS), 30-day readmission rates, and ventilator use. Unadjusted descriptive analysis was performed using chi-squared or paired t-tests to compare outcomes between the two cohorts. Results A total of 63,974 patients were identified in each cohort. The total hospitalization cost per visit for the FO cohort was US$15,344 higher than the non-FO cohort (US$42,386 vs US$27,042), and the ICU cost for the FO cohort was US$5,243 higher than the non-FO cohort (US$10,902 vs US$5,659). FO patients had higher mortality (20% vs 16.8%), prolonged LOS (11.5 vs 8.0 days), longer ICU LOS (6.2 vs 3.6 days), higher risk of 30-day readmission (21.8% vs 21.3%), and ventilator usage (47.7% vs 28.3%) than the non-FO cohort (all P<0.05). Conclusion In patients receiving multiple continuous infusions, FO is associated with increased health care resources and costs. Maximally concentrating medications and proactively providing continuous medications in small-volume infusions (SVI) could be a potential solution to prevent iatrogenic FO in critically ill patients. Further prospective research is warranted to assess the impact of the SVI dispensing model on patient outcomes and health care costs. PMID:25548524

Prognosis for Mammographically Occult, Early-Stage Breast Cancer Patients Treated With Breast-Conservation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Tzu-I. J.; Yang Qifeng; Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan

2010-01-15

Purpose: To compare mammographically occult (MamOcc) and mammographically positive (MamPos) early-stage breast cancer patients treated with breast-conservation therapy (BCT), to analyze differences between the two cohorts. Methods and Materials: Our two cohorts consisted of 214 MamOcc and 2168 MamPos patients treated with BCT. Chart reviews were conducted to assess mammogram reports and method of detection. All clinical-pathologic and outcome parameters were analyzed to detect differences between the two cohorts. Results: Median follow-up was 7 years. There were no differences in final margins, T stage, nodal status, estrogen/progesterone receptor status, or 'triple-negative' status. Significant differences included younger age at diagnosis (pmore » < 0.0001), more positive family history (p = 0.0033), less HER-2+ disease (p = 0.0294), and 1{sup o} histology (p < 0.0001). At 10 years, the differences in overall survival, cause-specific survival, and distant relapse between the two groups did not differ significantly. The MamOcc cohort had more breast relapses (15% vs. 8%; p = 0.0357), but on multivariate analysis this difference was not significant (hazard ratio 1.0, 95% confidence interval 0.993-1.007, p = 0.9296). Breast relapses were mammographically occult in 32% of the MamOcc and 12% of the MamPos cohorts (p = 0.0136). Conclusions: Although our study suggests that there are clinical-pathologic variations for the MamOcc cohort vs. MamPos patients that may ultimately affect management, breast relapse after BCT was not significantly different. Breast recurrences were more often mammographically occult in the MamOcc cohort; consideration should be given to closer follow-up and alternative imaging strategies (ultrasound, breast MRI) for routine posttreatment examination. To our knowledge, this represents the largest series addressing the prognostic significance of MamOcc cancers treated with BCT.« less

Primary central nervous system lymphoma and glioblastoma differentiation based on conventional magnetic resonance imaging by high-throughput SIFT features.

PubMed

Chen, Yinsheng; Li, Zeju; Wu, Guoqing; Yu, Jinhua; Wang, Yuanyuan; Lv, Xiaofei; Ju, Xue; Chen, Zhongping

2018-07-01

Due to the totally different therapeutic regimens needed for primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM), accurate differentiation of the two diseases by noninvasive imaging techniques is important for clinical decision-making. Thirty cases of PCNSL and 66 cases of GBM with conventional T1-contrast magnetic resonance imaging (MRI) were analyzed in this study. Convolutional neural networks was used to segment tumor automatically. A modified scale invariant feature transform (SIFT) method was utilized to extract three-dimensional local voxel arrangement information from segmented tumors. Fisher vector was proposed to normalize the dimension of SIFT features. An improved genetic algorithm (GA) was used to extract SIFT features with PCNSL and GBM discrimination ability. The data-set was divided into a cross-validation cohort and an independent validation cohort by the ratio of 2:1. Support vector machine with the leave-one-out cross-validation based on 20 cases of PCNSL and 44 cases of GBM was employed to build and validate the differentiation model. Among 16,384 high-throughput features, 1356 features show significant differences between PCNSL and GBM with p < 0.05 and 420 features with p < 0.001. A total of 496 features were finally chosen by improved GA algorithm. The proposed method produces PCNSL vs. GBM differentiation with an area under the curve (AUC) curve of 99.1% (98.2%), accuracy 95.3% (90.6%), sensitivity 85.0% (80.0%) and specificity 100% (95.5%) on the cross-validation cohort (and independent validation cohort). Since the local voxel arrangement characterization provided by SIFT features, proposed method produced more competitive PCNSL and GBM differentiation performance by using conventional MRI than methods based on advanced MRI.

Assisted reproductive technology has no association with autism spectrum disorders: The Taiwan Birth Cohort Study.

PubMed

Lung, For-Wey; Chiang, Tung-Liang; Lin, Shio-Jean; Lee, Meng-Chih; Shu, Bih-Ching

2018-04-01

The use of assisted reproduction technology has increased over the last two decades. Autism spectrum disorders and assisted reproduction technology share many risk factors. However, previous studies on the association between autism spectrum disorders and assisted reproduction technology have shown inconsistent results. The purpose of this study was to investigate the association between assisted reproduction technology and autism spectrum disorder diagnosis in a national birth cohort database. Furthermore, the results from the assisted reproduction technology and autism spectrum disorder propensity score matching exact matched datasets were compared. For this study, the 6- and 66-month Taiwan Birth Cohort Study datasets were used (N = 20,095). In all, 744 families were propensity score matching exact matched and selected as the assisted reproduction technology sample (ratio of assisted reproduction technology to controls: 1:2) and 415 families as the autism spectrum disorder sample (ratio of autism spectrum disorder to controls: 1:4). Using a national birth cohort dataset, controlling for the confounding factors of assisted reproduction technology conception and autism spectrum disorder diagnosis, both assisted reproduction technology and autism spectrum disorder propensity score matching matched datasets showed the same results of no association between assisted reproduction technology and autism spectrum disorder. Further study on the detailed information regarding the processes and methods of assisted reproduction technology may provide us with more information on the association between assisted reproduction technology and autism spectrum disorder.

Nested case-control studies: should one break the matching?

PubMed

Borgan, Ørnulf; Keogh, Ruth

2015-10-01

In a nested case-control study, controls are selected for each case from the individuals who are at risk at the time at which the case occurs. We say that the controls are matched on study time. To adjust for possible confounding, it is common to match on other variables as well. The standard analysis of nested case-control data is based on a partial likelihood which compares the covariates of each case to those of its matched controls. It has been suggested that one may break the matching of nested case-control data and analyse them as case-cohort data using an inverse probability weighted (IPW) pseudo likelihood. Further, when some covariates are available for all individuals in the cohort, multiple imputation (MI) makes it possible to use all available data in the cohort. In the paper we review the standard method and the IPW and MI approaches, and compare their performance using simulations that cover a range of scenarios, including one and two endpoints.

An Automatic Approach for Analyzing Treatment Effectiveness Based on Medication Hierarchy - The Myocardial Infarction Case Study.

PubMed

Li, Yingxue; Hu, Yiying; Yang, Jingang; Li, Xiang; Liu, Haifeng; Xie, Guotong; Xu, Meilin; Hu, Jingyi; Yang, Yuejin

2017-01-01

Treatment effectiveness plays a fundamental role in patient therapies. In most observational studies, researchers often design an analysis pipeline for a specific treatment based on the study cohort. To evaluate other treatments in the data set, much repeated and multifarious work including cohort construction, statistical analysis need to be done. In addition, as treatments are often with an intrinsic hierarchical relationship, many rational comparable treatment pairs can be derived as new treatment variables besides the original single treatment one from the original cohort data set. In this paper, we propose an automatic treatment effectiveness analysis approach to solve this problem. With our approach, clinicians can assess the effect of treatments not only more conveniently but also more thoroughly and comprehensively. We applied this method to a real world case of estimating the drug effectiveness on Chinese Acute Myocardial Infarction (CAMI) data set and some meaningful results are obtained for potential improvement of patient treatments.

Economic difficulties and subsequent sleep problems: Evidence from British and Finnish occupational cohorts

PubMed Central

Lallukka, Tea; Ferrie, Jane E.; Kivimäki, Mika; Shipley, Martin J.; Rahkonen, Ossi; Lahelma, Eero

2012-01-01

Background Social determinants of sleep may prove to be as important as health status. In this study we examined the extent to which persistent and changing economic difficulties are associated with sleep problems in two prospective occupational cohorts. Methods We used data from Finnish (baseline 2000–2002; follow-up 2007; n = 6328) and British (baseline 1997–1999; follow-up 2003–2004; n = 5002) public sector employees. Economic difficulties, sleep problems, and a variety of covariates were assessed at baseline and follow-up. Results Prevalence of frequent sleep problems at follow-up was 27% and 20% among women and men in the Finnish cohort, and 34% and 27% in the British cohort, respectively. Odds for sleep problems were higher among those with persistent economic difficulties (frequent economic difficulties at baseline and follow-up) compared to those with no difficulties. This association remained after multiple adjustments, including parental and current socioeconomic position, in the Finnish (OR 1.72, 95% CI 1.35–2.18) cohort. Increases in economic difficulties were similarly associated with sleep problems in the Finnish and the British cohort. Conclusion Evidence from two occupational cohorts suggests strong associations between economic difficulty and poor sleep. Awareness of this association will help health care professionals identify and prevent sleep problems. PMID:22445231

Influence of the Size of Cohorts in Adaptive Design for Nonlinear Mixed Effects Models: An Evaluation by Simulation for a Pharmacokinetic and Pharmacodynamic Model for a Biomarker in Oncology

PubMed Central

Lestini, Giulia; Dumont, Cyrielle; Mentré, France

2015-01-01

Purpose In this study we aimed to evaluate adaptive designs (ADs) by clinical trial simulation for a pharmacokinetic-pharmacodynamic model in oncology and to compare them with one-stage designs, i.e. when no adaptation is performed, using wrong prior parameters. Methods We evaluated two one-stage designs, ξ0 and ξ*, optimised for prior and true population parameters, Ψ0 and Ψ*, and several ADs (two-, three- and five-stage). All designs had 50 patients. For ADs, the first cohort design was ξ0. The next cohort design was optimised using prior information updated from the previous cohort. Optimal design was based on the determinant of the Fisher information matrix using PFIM. Design evaluation was performed by clinical trial simulations using data simulated from Ψ*. Results Estimation results of two-stage ADs and ξ* were close and much better than those obtained with ξ0. The balanced two-stage AD performed better than two-stage ADs with different cohort sizes. Three-and five-stage ADs were better than two-stage with small first cohort, but not better than the balanced two-stage design. Conclusions Two-stage ADs are useful when prior parameters are unreliable. In case of small first cohort, more adaptations are needed but these designs are complex to implement. PMID:26123680

The Use of Intraoperative Sensors Significantly Increases the Patient-Reported Rate of Improvement in Primary Total Knee Arthroplasty.

PubMed

Chow, James C; Breslauer, Leigh

2017-07-01

Albeit multifactorial, patient satisfaction is predominantly driven by postoperative pain and function. Unfortunately, approximately 20% of total knee arthroplasty (TKA) recipients are dissatisfied with the outcome of their surgery. Objective balancing of the soft tissue envelope may contribute to significant decrease in pain and increase in function when compared with traditional subjective methods. In an effort to confirm this, a cohort of manual TKA patient outcomes was compared with sensor-assisted TKA outcomes. One hundred fourteen patients (57 manual, 57 sensor assisted) received primary TKA. Both cohorts were matched for confounding variables. The dependent variables in this study were 6-month patient-reported outcome measures, including Knee Society Score and Oxford Knee Score. The range of motion and incidence of arthrofibrosis were also captured for both cohorts. The rate of improvement of all patient-reported outcome scores and subscores and range of motion was significantly higher in the sensor-assisted cohort. The rate of arthrofibrosis was lower in the sensor-assisted cohort but not statistically significant. The authors rejected the null hypothesis and concluded that the rate of improvement in objective, patient-reported outcome measures was higher in the sensor-assisted cohort than the manual cohort from preoperatively to 6 months postoperatively. [Orthopedics. 2017; 40(4):e648-e651.]. Copyright 2017, SLACK Incorporated.

An economic evaluation of an integrated care pathway in geriatric rehabilitation for older patients with complex health problems

PubMed Central

van Haastregt, Jolanda C. M.; Evers, Silvia M. A. A.; Kempen, Gertrudis I. J. M.; Schols, Jos M. G. A.

2018-01-01

Background Integrated care pathways which cover multiple care settings are increasingly used as a tool to structure care, enhance coordination and improve transitions between care settings. However, little is known about their economic impact. The objective of this study is to determine the cost-effectiveness and cost-utility of an integrated care pathway designed for patients with complex health problems transferring from the hospital, a geriatric rehabilitation facility and primary care. Methods This economic evaluation was performed from a societal perspective alongside a prospective cohort study with two cohorts of patients. The care as usual cohort was included before implementation of the pathway and the care pathway cohort after implementation of the pathway. Both cohorts were measured over nine months, during which intervention costs, healthcare costs, patient and family costs were identified. The outcome measures were dependence in activities of daily living (measured with the KATZ-15) and quality adjusted life years (EQ-5D-3L). Costs and effects were bootstrapped and various sensitivity analyses were performed to assess robustness of the results. Results After nine months, the average societal costs were significantly lower for patients in the care pathway cohort (€50,791) versus patients in the care as usual cohort (€62,170; CI = -22,090, -988). Patients in the care pathway cohort had better scores on the KATZ-15 (1.04), indicating cost-effectiveness. No significant differences were found between the two groups on QALY scores (0.01). Conclusions The results of this study indicate that the integrated care pathway is a cost-effective intervention. Therefore, dissemination of the integrated care pathway on a wider scale could be considered. This would provide us the opportunity to confirm the findings of our study in larger economic evaluations. When looking at QALYs, no effects were found. Therefore, it is also recommended to explore if therapy in geriatric rehabilitation could also pay attention to other quality of life-related domains, such as mood and social participation. PMID:29489820

Cohort profile: Study of Transition, Outcomes and Gender (STRONG) to assess health status of transgender people.

PubMed

Quinn, Virginia P; Nash, Rebecca; Hunkeler, Enid; Contreras, Richard; Cromwell, Lee; Becerra-Culqui, Tracy A; Getahun, Darios; Giammattei, Shawn; Lash, Timothy L; Millman, Andrea; Robinson, Brandi; Roblin, Douglas; Silverberg, Michael J; Slovis, Jennifer; Tangpricha, Vin; Tolsma, Dennis; Valentine, Cadence; Ward, Kevin; Winter, Savannah; Goodman, Michael

2017-12-27

The Study of Transition, Outcomes and Gender (STRONG) was initiated to assess the health status of transgender people in general and following gender-affirming treatments at Kaiser Permanente health plans in Georgia, Northern California and Southern California. The objectives of this communication are to describe methods of cohort ascertainment and data collection and to characterise the study population. A stepwise methodology involving computerised searches of electronic medical records and free-text validation of eligibility and gender identity was used to identify a cohort of 6456 members with first evidence of transgender status (index date) between 2006 and 2014. The cohort included 3475 (54%) transfeminine (TF), 2892 (45%) transmasculine (TM) and 89 (1%) members whose natal sex and gender identity remained undetermined from the records. The cohort was matched to 127 608 enrollees with no transgender evidence (63 825 women and 63 783 men) on year of birth, race/ethnicity, study site and membership year of the index date. Cohort follow-up extends through the end of 2016. About 58% of TF and 52% of TM cohort members received hormonal therapy at Kaiser Permanente. Chest surgery was more common among TM participants (12% vs 0.3%). The proportions of transgender participants who underwent genital reconstruction surgeries were similar (4%-5%) in the two transgender groups. Results indicate that there are sufficient numbers of events in the TF and TM cohorts to further examine mental health status, cardiovascular events, diabetes, HIV and most common cancers. STRONG is well positioned to fill existing knowledge gaps through comparisons of transgender and reference populations and through analyses of health status before and after gender affirmation treatment. Analyses will include incidence of cardiovascular disease, mental health, HIV and diabetes, as well as changes in laboratory-based endpoints (eg, polycythemia and bone density), overall and in relation to gender affirmation therapy. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Students' attitudes and perceptions of teaching and assessment of evidence-based practice in an occupational therapy professional Master's curriculum: a mixed methods study.

PubMed

Thomas, Aliki; Han, Lu; Osler, Brittony P; Turnbull, Emily A; Douglas, Erin

2017-03-27

Most health professions, including occupational therapy, have made the application of evidence-based practice a desired competency and professional responsibility. Despite the increasing emphasis on evidence-based practice for improving patient outcomes, there are numerous research-practice gaps in the health professions. In addition to efforts aimed at promoting evidence-based practice with clinicians, there is a strong impetus for university programs to design curricula that will support the development of the knowledge, attitudes, skills and behaviours associated with evidence-based practice. Though occupational therapy curricula in North America are becoming increasingly focused on evidence-based practice, research on students' attitudes towards evidence-based practice, their perceptions regarding the integration and impact of this content within the curricula, and the impact of the curriculum on their readiness for evidence-based practice is scarce. The present study examined occupational therapy students' perceptions towards the teaching and assessment of evidence-based practice within a professional master's curriculum and their self-efficacy for evidence-based practice. The study used a mixed methods explanatory sequential design. The quantitative phase included a cross-sectional questionnaire exploring attitudes towards evidence-based practice, perceptions of the teaching and assessment of evidence-based practice and evidence-based practice self-efficacy for four cohorts of students enrolled in the program and a cohort of new graduates. The questionnaire was followed by a focus group of senior students aimed at further exploring the quantitative findings. All student cohorts held favourable attitudes towards evidence-based practice; there was no difference across cohorts. There were significant differences with regards to perceptions of the teaching and assessment of evidence-based practice within the curriculum; junior cohorts and students with previous education had less favourable perceptions. Students' self-efficacy for evidence-based practice was significantly higher across cohorts. Four main themes emerged from the focus group data: (a) Having mixed feelings about the value of evidence-based practice (b) Barriers to the application of evidence-based practice; (c) Opposing worlds and (d) Vital and imperfect role of the curriculum. This study provides important data to support the design and revision of evidence-based practice curricula within professional rehabilitation programs.

Developing and Validating a Predictive Model for Stroke Progression

PubMed Central

Craig, L.E.; Wu, O.; Gilmour, H.; Barber, M.; Langhorne, P.

2011-01-01

Background Progression is believed to be a common and important complication in acute stroke, and has been associated with increased mortality and morbidity. Reliable identification of predictors of early neurological deterioration could potentially benefit routine clinical care. The aim of this study was to identify predictors of early stroke progression using two independent patient cohorts. Methods Two patient cohorts were used for this study – the first cohort formed the training data set, which included consecutive patients admitted to an urban teaching hospital between 2000 and 2002, and the second cohort formed the test data set, which included patients admitted to the same hospital between 2003 and 2004. A standard definition of stroke progression was used. The first cohort (n = 863) was used to develop the model. Variables that were statistically significant (p < 0.1) on univariate analysis were included in the multivariate model. Logistic regression was the technique employed using backward stepwise regression to drop the least significant variables (p > 0.1) in turn. The second cohort (n = 216) was used to test the performance of the model. The performance of the predictive model was assessed in terms of both calibration and discrimination. Multiple imputation methods were used for dealing with the missing values. Results Variables shown to be significant predictors of stroke progression were conscious level, history of coronary heart disease, presence of hyperosmolarity, CT lesion, living alone on admission, Oxfordshire Community Stroke Project classification, presence of pyrexia and smoking status. The model appears to have reasonable discriminative properties [the median receiver-operating characteristic curve value was 0.72 (range 0.72–0.73)] and to fit well with the observed data, which is indicated by the high goodness-of-fit p value [the median p value from the Hosmer-Lemeshow test was 0.90 (range 0.50–0.92)]. Conclusion The predictive model developed in this study contains variables that can be easily collected in practice therefore increasing its usability in clinical practice. Using this analysis approach, the discrimination and calibration of the predictive model appear sufficiently high to provide accurate predictions. This study also offers some discussion around the validation of predictive models for wider use in clinical practice. PMID:22566988

Cesarean delivery rates among family physicians versus obstetricians: a population-based cohort study using instrumental variable methods

PubMed Central

Dawe, Russell Eric; Bishop, Jessica; Pendergast, Amanda; Avery, Susan; Monaghan, Kelly; Duggan, Norah; Aubrey-Bassler, Kris

2017-01-01

Background: Previous research suggests that family physicians have rates of cesarean delivery that are lower than or equivalent to those for obstetricians, but adjustments for risk differences in these analyses may have been inadequate. We used an econometric method to adjust for observed and unobserved factors affecting the risk of cesarean delivery among women attended by family physicians versus obstetricians. Methods: This retrospective population-based cohort study included all Canadian (except Quebec) hospital deliveries by family physicians and obstetricians between Apr. 1, 2006, and Mar. 31, 2009. We excluded women with multiple gestations, and newborns with a birth weight less than 500 g or gestational age less than 20 weeks. We estimated the relative risk of cesarean delivery using instrumental-variable-adjusted and logistic regression. Results: The final cohort included 776 299 women who gave birth in 390 hospitals. The risk of cesarean delivery was 27.3%, and the mean proportion of deliveries by family physicians was 26.9% (standard deviation 23.8%). The relative risk of cesarean delivery for family physicians versus obstetricians was 0.48 (95% confidence interval [CI] 0.41-0.56) with logistic regression and 1.27 (95% CI 1.02-1.57) with instrumental-variable-adjusted regression. Interpretation: Our conventional analyses suggest that family physicians have a lower rate of cesarean delivery than obstetricians, but instrumental variable analyses suggest the opposite. Because instrumental variable methods adjust for unmeasured factors and traditional methods do not, the large discrepancy between these estimates of risk suggests that clinical and/or sociocultural factors affecting the decision to perform cesarean delivery may not be accounted for in our database. PMID:29233843

Adjuvant Chemotherapy and Trastuzumab Is Safe and Effective in Older Women With Small, Node-Negative, HER2-Positive Early-Stage Breast Cancer.

PubMed

Cadoo, Karen A; Morris, Patrick G; Cowell, Elizabeth P; Patil, Sujata; Hudis, Clifford A; McArthur, Heather L

2016-12-01

The benefit of adjuvant trastuzumab with chemotherapy is well established for women with higher risk human epidermal growth factor receptor 2-positive (HER2 + ) breast cancer. However, its role in older patients with smaller, node-negative tumors is less clear. We conducted a retrospective, sequential cohort study of this population to describe the impact of trastuzumab on breast cancer outcomes and cardiac safety. Women ≥ 55 years with ≤ 2 cm, node-negative, HER2 + breast cancer were identified and electronic medical records reviewed. A no-trastuzumab cohort of 116 women diagnosed between January 1, 1999 and May 14, 2004 and a trastuzumab cohort of 128 women diagnosed between May 16, 2006 and December 31, 2010 were identified. Overall survival and distant relapse-free survival were estimated by Kaplan-Meier methods. The median ages of the trastuzumab and no-trastuzumab cohorts were 62 and 64 years, respectively. More patients in the trastuzumab cohort had grade III (P = .001), lymphovascular invasion (P = .001), or estrogen receptor-negative (P < .001) cancers. The majority of the trastuzumab cohort received chemotherapy versus one-half of the no-trastuzumab cohort (98% vs. 53%; P < .0001). The median follow-up was 4 versus 9 years in the trastuzumab versus no-trastuzumab cohorts; therefore, outcomes at 4 years are reported. Despite the higher-risk tumor features in the trastuzumab group, the 4-year overall survival was 99% in both cohorts; the distant relapse-free survival was 99% versus 97% in the trastuzumab versus no-trastuzumab cohorts. Four (3.1%; 95% confidence interval, 1.0%-7.8%) women in the trastuzumab cohort and 1 in the no-trastuzumab cohort developed symptomatic heart failure. There were no cardiac-related deaths in either arm. Following adjuvant trastuzumab with chemotherapy, selected older women with small, node-negative, HER2 + breast cancers have excellent disease control. The rate of cardiac events is low. Copyright © 2016 Elsevier Inc. All rights reserved.

Serum 25-Hydroxyvitamin D3 Levels Are Associated With Breslow Thickness at Presentation and Survival From Melanoma

PubMed Central

Newton-Bishop, Julia A.; Beswick, Samantha; Randerson-Moor, Juliette; Chang, Yu-Mei; Affleck, Paul; Elliott, Faye; Chan, May; Leake, Susan; Karpavicius, Birute; Haynes, Sue; Kukalizch, Kairen; Whitaker, Linda; Jackson, Sharon; Gerry, Edwina; Nolan, Clarissa; Bertram, Chandra; Marsden, Jerry; Elder, David E.; Barrett, Jennifer H.; Bishop, D. Timothy

2009-01-01

Purpose A cohort study was carried out to test the hypothesis that higher vitamin D levels reduce the risk of relapse from melanoma. Methods A pilot retrospective study of 271 patients with melanoma suggested that vitamin D may protect against recurrence of melanoma. We tested these findings in a survival analysis in a cohort of 872 patients recruited to the Leeds Melanoma Cohort (median follow-up, 4.7 years). Results In the retrospective study, self-reports of taking vitamin D supplements were nonsignificantly correlated with a reduced risk of melanoma relapse (odds ratio = 0.6; 95% CI, 0.4 to 1.1; P = .09). Nonrelapsers had higher mean 25-hydroxyvitamin D3 levels than relapsers (49 v 46 nmol/L; P = .3; not statistically significant). In the cohort (prospective) study, higher 25-hydroxyvitamin D3 levels were associated with lower Breslow thickness at diagnosis (P = .002) and were independently protective of relapse and death: the hazard ratio for relapse-free survival (RFS) was 0.79 (95% CI, 0.64 to 0.96; P = .01) for a 20 nmol/L increase in serum level. There was evidence of interaction between the vitamin D receptor (VDR) BsmI genotype and serum 25-hydroxyvitamin D3 levels on RFS. Conclusion Results from the retrospective study were consistent with a role for vitamin D in melanoma outcome. The cohort study tests this hypothesis, providing evidence that higher 25-hydroxyvitamin D3 levels, at diagnosis, are associated with both thinner tumors and better survival from melanoma, independent of Breslow thickness. Patients with melanoma, and those at high risk of melanoma, should seek to ensure vitamin D sufficiency. Additional studies are needed to establish optimal serum levels for patients with melanoma. PMID:19770375

Study design of DIACORE (DIAbetes COhoRtE) – a cohort study of patients with diabetes mellitus type 2

PubMed Central

2013-01-01

Background Diabetes mellitus type 2 (DM2) is highly associated with increased risk for chronic kidney disease (CKD), end stage renal disease (ESRD) and cardiovascular morbidity. Epidemiological and genetic studies generate hypotheses for innovative strategies in DM2 management by unravelling novel mechanisms of diabetes complications, which is essential for future intervention trials. We have thus initiated the DIAbetes COhoRtE study (DIACORE). Methods DIACORE is a prospective cohort study aiming to recruit 6000 patients of self-reported Caucasian ethnicity with prevalent DM2 for at least 10 years of follow-up. Study visits are performed in University-based recruiting clinics in Germany using standard operating procedures. All prevalent DM2 patients in outpatient clinics surrounding the recruiting centers are invited to participate. At baseline and at each 2-year follow-up examination, patients are subjected to a core phenotyping protocol. This includes a standardized online questionnaire and physical examination to determine incident micro- and macrovascular DM2 complications, malignancy and hospitalization, with a primary focus on renal events. Confirmatory outcome information is requested from patient records. Blood samples are obtained for a centrally analyzed standard laboratory panel and for biobanking of aliquots of serum, plasma, urine, mRNA and DNA for future scientific use. A subset of the cohort is subjected to extended phenotyping, e.g. sleep apnea screening, skin autofluorescence measurement, non-mydriatic retinal photography and non-invasive determination of arterial stiffness. Discussion DIACORE will enable the prospective evaluation of factors involved in DM2 complication pathogenesis using high-throughput technologies in biosamples and genetic epidemiological studies. PMID:23409726

Prognostic factors in non-surgically treated sciatica: A systematic review

PubMed Central

2011-01-01

Background When present sciatica is considered an obstacle to recovery in low back pain patients, yet evidence is limited regarding prognostic factors for persistent disability in this patient group. The aim of this study is to describe and summarise the evidence regarding prognostic factors for sciatica in non-surgically treated cohorts. Understanding the prognostic factors in sciatica and their relative importance may allow the identification of patients with particular risk factors who might benefit from early or specific types of treatment in order to optimise outcome. Methods A systematic literature search was conducted using Medline, EMBASE and CINAHL electronic databases. Prospective cohort studies describing subjects with sciatica and measuring pain, disability or recovery outcomes were included. Studies of cohorts comprised entirely of surgically treated patients were excluded and mixed surgically and conservatively treated cohorts were included only if the results were analysed separately by treatment group or if the analysis was adjusted for treatment. Results Seven adequate or high quality eligible studies were identified. There were conflicting but mainly negative results regarding the influence of baseline pain severity, neurological deficit, nerve root tension signs, duration of symptoms and radiological findings on outcome. A number of factors including age, gender, smoking, previous history of sciatica and heaviness of work do not appear to influence outcome. In contrast to studies of low back pain and purely surgically treated sciatica cohorts, psychological factors were rarely investigated. Conclusions At present, the heterogeneity of the available studies makes it difficult to draw firm conclusions about sciatica prognosis, and highlights the need for further research for this group of patients. Large scale prospective studies of high methodological quality, using a well-defined, consistent definition of sciatica and investigating psychosocial factors alongside clinical and radiological findings are recommended to identify prognostic factors in this population. PMID:21943339

Mortality in the Medicare Population and Chronic Exposure to Fine Particulate Air Pollution in Urban Centers (2000–2005)

PubMed Central

Zeger, Scott L.; Dominici, Francesca; McDermott, Aidan; Samet, Jonathan M.

2008-01-01

Background Prospective cohort studies constitute the major source of evidence about the mortality effects of chronic exposure to particulate air pollution. Additional studies are needed to provide evidence on the health effects of chronic exposure to particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) because few studies have been carried out and the cohorts have not been representative. Objectives This study was designed to estimate the relative risk of death associated with long-term exposure to PM2.5 by region and age groups in a U.S. population of elderly, for the period 2000–2005. Methods By linking PM2.5 monitoring data to the Medicare billing claims by ZIP code of residence of the enrollees, we have developed a new retrospective cohort study, the Medicare Cohort Air Pollution Study. The study population comprises 13.2 million participants living in 4,568 ZIP codes having centroids within 6 miles of a PM2.5 monitor. We estimated relative risks adjusted by socioeconomic status and smoking by fitting log-linear regression models. Results In the eastern and central regions, a 10-μg/m3 increase in 6-year average of PM2.5 is associated with 6.8% [95% confidence interval (CI), 4.9–8.7%] and 13.2% (95% CI, 9.5–16.9) increases in mortality, respectively. We found no evidence of an association in the western region or for persons ≥ 85 years of age. Conclusions We established a cohort of Medicare participants for investigating air pollution and mortality on longer-term time frames. Chronic exposure to PM2.5 was associated with mortality in the eastern and central regions, but not in the western United States. PMID:19079710

Parameter estimation in Cox models with missing failure indicators and the OPPERA study.

PubMed

Brownstein, Naomi C; Cai, Jianwen; Slade, Gary D; Bair, Eric

2015-12-30

In a prospective cohort study, examining all participants for incidence of the condition of interest may be prohibitively expensive. For example, the "gold standard" for diagnosing temporomandibular disorder (TMD) is a physical examination by a trained clinician. In large studies, examining all participants in this manner is infeasible. Instead, it is common to use questionnaires to screen for incidence of TMD and perform the "gold standard" examination only on participants who screen positively. Unfortunately, some participants may leave the study before receiving the "gold standard" examination. Within the framework of survival analysis, this results in missing failure indicators. Motivated by the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study, a large cohort study of TMD, we propose a method for parameter estimation in survival models with missing failure indicators. We estimate the probability of being an incident case for those lacking a "gold standard" examination using logistic regression. These estimated probabilities are used to generate multiple imputations of case status for each missing examination that are combined with observed data in appropriate regression models. The variance introduced by the procedure is estimated using multiple imputation. The method can be used to estimate both regression coefficients in Cox proportional hazard models as well as incidence rates using Poisson regression. We simulate data with missing failure indicators and show that our method performs as well as or better than competing methods. Finally, we apply the proposed method to data from the OPPERA study. Copyright © 2015 John Wiley & Sons, Ltd.

The Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study: rationale and methods.

PubMed

Kaplan, Bonnie J; Giesbrecht, Gerald F; Leung, Brenda M Y; Field, Catherine J; Dewey, Deborah; Bell, Rhonda C; Manca, Donna P; O'Beirne, Maeve; Johnston, David W; Pop, Victor J; Singhal, Nalini; Gagnon, Lisa; Bernier, Francois P; Eliasziw, Misha; McCargar, Linda J; Kooistra, Libbe; Farmer, Anna; Cantell, Marja; Goonewardene, Laki; Casey, Linda M; Letourneau, Nicole; Martin, Jonathan W

2014-01-01

The Alberta Pregnancy Outcomes and Nutrition (APrON) study is an ongoing prospective cohort study that recruits pregnant women early in pregnancy and, as of 2012, is following up their infants to 3 years of age. It has currently enrolled approximately 5000 Canadians (2000 pregnant women, their offspring and many of their partners). The primary aims of the APrON study were to determine the relationships between maternal nutrient intake and status, before, during and after gestation, and (1) maternal mood; (2) birth and obstetric outcomes; and (3) infant neurodevelopment. We have collected comprehensive maternal nutrition, anthropometric, biological and mental health data at multiple points in the pregnancy and the post-partum period, as well as obstetrical, birth, health and neurodevelopmental outcomes of these pregnancies. The study continues to follow the infants through to 36 months of age. The current report describes the study design and methods, and findings of some pilot work. The APrON study is a significant resource with opportunities for collaboration. © 2012 John Wiley & Sons Ltd.

Exploratory factor analysis of self-reported symptoms in a large, population-based military cohort

PubMed Central

2010-01-01

Background US military engagements have consistently raised concern over the array of health outcomes experienced by service members postdeployment. Exploratory factor analysis has been used in studies of 1991 Gulf War-related illnesses, and may increase understanding of symptoms and health outcomes associated with current military conflicts in Iraq and Afghanistan. The objective of this study was to use exploratory factor analysis to describe the correlations among numerous physical and psychological symptoms in terms of a smaller number of unobserved variables or factors. Methods The Millennium Cohort Study collects extensive self-reported health data from a large, population-based military cohort, providing a unique opportunity to investigate the interrelationships of numerous physical and psychological symptoms among US military personnel. This study used data from the Millennium Cohort Study, a large, population-based military cohort. Exploratory factor analysis was used to examine the covariance structure of symptoms reported by approximately 50,000 cohort members during 2004-2006. Analyses incorporated 89 symptoms, including responses to several validated instruments embedded in the questionnaire. Techniques accommodated the categorical and sometimes incomplete nature of the survey data. Results A 14-factor model accounted for 60 percent of the total variance in symptoms data and included factors related to several physical, psychological, and behavioral constructs. A notable finding was that many factors appeared to load in accordance with symptom co-location within the survey instrument, highlighting the difficulty in disassociating the effects of question content, location, and response format on factor structure. Conclusions This study demonstrates the potential strengths and weaknesses of exploratory factor analysis to heighten understanding of the complex associations among symptoms. Further research is needed to investigate the relationship between factor analytic results and survey structure, as well as to assess the relationship between factor scores and key exposure variables. PMID:20950474

Development in Children with Achondroplasia: A Prospective Clinical Cohort Study

ERIC Educational Resources Information Center

Ireland, Penelope J.; Donaghey, Samantha; McGill, James; Zankl, Andreas; Ware, Robert S.; Pacey, Verity; Ault, Jenny; Savarirayan, Ravi; Sillence, David; Thompson, Elizabeth; Townshend, Sharron; Johnston, Leanne M.

2012-01-01

Aim: Achondroplasia is characterized by delays in the development of communication and motor skills. While previously reported developmental profiles exist across gross motor, fine motor, feeding, and communication skills, there has been no prospective study of development across multiple areas simultaneously. Method: This Australasian…

A QUANTITATIVE APPROACH FOR ESTIMATING EXPOSURE TO PESTICIDES IN THE AGRICULTURAL HEALTH STUDY

EPA Science Inventory

We developed a quantitative method to estimate chemical-specific pesticide exposures in a large prospective cohort study of over 58,000 pesticide applicators in North Carolina and Iowa. An enrollment questionnaire was administered to applicators to collect basic time- and inten...

A randomized, open-label study to investigate the effect of belimumab on pneumococcal vaccination in patients with active, autoantibody-positive systemic lupus erythematosus

PubMed Central

Chadha, A; Fettiplace, J; Kleoudis, C; Bass, D; Roth, D; Gordon, D

2017-01-01

Objective Intravenous belimumab 10 mg/kg is approved as an add-on therapy in patients with active, autoantibody-positive systemic lupus erythematosus. This study aimed to assess the impact of belimumab on immune response to pneumococcal vaccination in patients with systemic lupus erythematosus. Methods This was a Phase 4, open-label study (GSK BEL115470; NCT01597492) conducted in the United States. Patients were randomized (7:9) to receive a 23-valent pneumococcal vaccination four weeks prior to (pre-belimumab cohort) or 24 weeks after (belimumab-concurrent cohort) commencing four-weekly belimumab 10 mg/kg intravenous treatment plus standard systemic lupus erythematosus therapy. Analyses of vaccine titers were performed on the as-treated population (received ≥1 dose of belimumab). The primary endpoint was the proportion of patients with positive antibody responses (≥2-fold increase from pre-vaccination levels, or post-vaccination level ≥ 0.6 µg/mL if pre-vaccination levels were unquantifiable) to ≥1 of 23 pneumococcal vaccine serotypes, four weeks post vaccination. Other endpoints included the proportion of patients with positive antibody responses to ≥2 to ≥10, and ≥11–23 (post hoc analysis) of serotypes. Safety was assessed by monitoring adverse events. Results Seventy-nine patients received pneumococcal vaccination (pre-belimumab cohort, n = 34; belimumab-concurrent cohort, n = 45). The majority (87.3% [69/79]) completed the study; 10 (12.7%) withdrew (patient request, n = 3; adverse event, n = 3; lost to follow-up, n = 2; other, n = 2). At Week 4 post-vaccination, 97.0% (32/33) and 97.6% (40/41) of patients (pre-belimumab and concurrent belimumab cohorts, respectively) had a positive response to ≥1 of 23 pneumococcal serotypes. Over 85% of patients in both cohorts responded to ≥10 of serotypes, approximately 80% responded to ≥12 serotypes, and approximately two-thirds responded to ≥16 serotypes. Little difference was observed between cohorts across a broad response, up to 23 serotypes. Eight (23.5%) patients experienced an adverse event considered by the investigator to be treatment-related in the pre-belimumab cohort and four (8.9%) in the belimumab-concurrent cohort; seven patients experienced non-fatal serious adverse events (pre-belimumab cohort, 11.8% [n = 4]; concurrent-belimumab cohort, 6.7% [n = 3]), and no deaths were reported. Conclusion The proportion of patients generating a response to ≥1 pneumococcal serotype did not differ between the pre-belimumab and belimumab-concurrent cohorts; the proportions were also comparable across a broader response (from ≥2 serotypes to 23 serotypes). PMID:28467293

A randomized, open-label study to investigate the effect of belimumab on pneumococcal vaccination in patients with active, autoantibody-positive systemic lupus erythematosus.

PubMed

Chatham, W; Chadha, A; Fettiplace, J; Kleoudis, C; Bass, D; Roth, D; Gordon, D

2017-12-01

Objective Intravenous belimumab 10 mg/kg is approved as an add-on therapy in patients with active, autoantibody-positive systemic lupus erythematosus. This study aimed to assess the impact of belimumab on immune response to pneumococcal vaccination in patients with systemic lupus erythematosus. Methods This was a Phase 4, open-label study (GSK BEL115470; NCT01597492) conducted in the United States. Patients were randomized (7:9) to receive a 23-valent pneumococcal vaccination four weeks prior to (pre-belimumab cohort) or 24 weeks after (belimumab-concurrent cohort) commencing four-weekly belimumab 10 mg/kg intravenous treatment plus standard systemic lupus erythematosus therapy. Analyses of vaccine titers were performed on the as-treated population (received ≥1 dose of belimumab). The primary endpoint was the proportion of patients with positive antibody responses (≥2-fold increase from pre-vaccination levels, or post-vaccination level ≥ 0.6 µg/mL if pre-vaccination levels were unquantifiable) to ≥1 of 23 pneumococcal vaccine serotypes, four weeks post vaccination. Other endpoints included the proportion of patients with positive antibody responses to ≥2 to ≥10, and ≥11-23 (post hoc analysis) of serotypes. Safety was assessed by monitoring adverse events. Results Seventy-nine patients received pneumococcal vaccination (pre-belimumab cohort, n = 34; belimumab-concurrent cohort, n = 45). The majority (87.3% [69/79]) completed the study; 10 (12.7%) withdrew (patient request, n = 3; adverse event, n = 3; lost to follow-up, n = 2; other, n = 2). At Week 4 post-vaccination, 97.0% (32/33) and 97.6% (40/41) of patients (pre-belimumab and concurrent belimumab cohorts, respectively) had a positive response to ≥1 of 23 pneumococcal serotypes. Over 85% of patients in both cohorts responded to ≥10 of serotypes, approximately 80% responded to ≥12 serotypes, and approximately two-thirds responded to ≥16 serotypes. Little difference was observed between cohorts across a broad response, up to 23 serotypes. Eight (23.5%) patients experienced an adverse event considered by the investigator to be treatment-related in the pre-belimumab cohort and four (8.9%) in the belimumab-concurrent cohort; seven patients experienced non-fatal serious adverse events (pre-belimumab cohort, 11.8% [ n = 4]; concurrent-belimumab cohort, 6.7% [ n = 3]), and no deaths were reported. Conclusion The proportion of patients generating a response to ≥1 pneumococcal serotype did not differ between the pre-belimumab and belimumab-concurrent cohorts; the proportions were also comparable across a broader response (from ≥2 serotypes to 23 serotypes).

The Evolution of Qualitative and Quantitative Research Classes when Delivered via Distance Education.

ERIC Educational Resources Information Center

Hecht, Jeffrey B.; Klass, Patricia H.

This study examined whether new streamed Internet audio and video technology could be used for primary instruction in off-campus research classes. Several different off-campus student cohorts at Illinois State university enrolled in both a fall semester qualitative research methods class and a spring semester quantitative research methods class.…

Exploring Formative Assessment as a Tool for Learning: Students' Experiences of Different Methods of Formative Assessment

ERIC Educational Resources Information Center

Weurlander, Maria; Soderberg, Magnus; Scheja, Max; Hult, Hakan; Wernerson, Annika

2012-01-01

This study aims to provide a greater insight into how formative assessments are experienced and understood by students. Two different formative assessment methods, an individual, written assessment and an oral group assessment, were components of a pathology course within a medical curriculum. In a cohort of 70 students, written accounts were…

Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae) in Eastern Arabian Sea.

PubMed

Sasikumarl, Geetha; Mohamed, K S; Bhat, U S

2013-03-01

Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea (South-West coast of India). For this, the Dorsal Mantle Length (DML) and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modal-progression analysis using the Bhattacharya's method for the estimation of growth. The estimated parameters Linfinity and K in von Bertalanffy Growth Function (VBGF) were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort) which supports the major fishery, was composed of medium-sized, fast growing individuals, whereas the second cohort (pre-monsoon cohort), comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3 years for males and 2.1 years for females. Negative allometric growth in weight (W) with length (L) was observed for males (W=0.33069.L2.5389) and females (W=0.32542.L26057). The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in comparison with 0.03-0.85kg/h in December-April. Seasonal catch rates indicated a migratory life cycle ofS. pharaonis between offshore and inshore coastal zones.

Modeling and E-M estimation of haplotype-specific relative risks from genotype data for a case-control study of unrelated individuals.

PubMed

Stram, Daniel O; Leigh Pearce, Celeste; Bretsky, Phillip; Freedman, Matthew; Hirschhorn, Joel N; Altshuler, David; Kolonel, Laurence N; Henderson, Brian E; Thomas, Duncan C

2003-01-01

The US National Cancer Institute has recently sponsored the formation of a Cohort Consortium (http://2002.cancer.gov/scpgenes.htm) to facilitate the pooling of data on very large numbers of people, concerning the effects of genes and environment on cancer incidence. One likely goal of these efforts will be generate a large population-based case-control series for which a number of candidate genes will be investigated using SNP haplotype as well as genotype analysis. The goal of this paper is to outline the issues involved in choosing a method of estimating haplotype-specific risk estimates for such data that is technically appropriate and yet attractive to epidemiologists who are already comfortable with odds ratios and logistic regression. Our interest is to develop and evaluate extensions of methods, based on haplotype imputation, that have been recently described (Schaid et al., Am J Hum Genet, 2002, and Zaykin et al., Hum Hered, 2002) as providing score tests of the null hypothesis of no effect of SNP haplotypes upon risk, which may be used for more complex tasks, such as providing confidence intervals, and tests of equivalence of haplotype-specific risks in two or more separate populations. In order to do so we (1) develop a cohort approach towards odds ratio analysis by expanding the E-M algorithm to provide maximum likelihood estimates of haplotype-specific odds ratios as well as genotype frequencies; (2) show how to correct the cohort approach, to give essentially unbiased estimates for population-based or nested case-control studies by incorporating the probability of selection as a case or control into the likelihood, based on a simplified model of case and control selection, and (3) finally, in an example data set (CYP17 and breast cancer, from the Multiethnic Cohort Study) we compare likelihood-based confidence interval estimates from the two methods with each other, and with the use of the single-imputation approach of Zaykin et al. applied under both null and alternative hypotheses. We conclude that so long as haplotypes are well predicted by SNP genotypes (we use the Rh2 criteria of Stram et al. [1]) the differences between the three methods are very small and in particular that the single imputation method may be expected to work extremely well. Copyright 2003 S. Karger AG, Basel

Association between Breast Feeding and Paediatric Sleep Disordered Breathing: a Systematic Review.

PubMed

Ponce-Garcia, Cecilia; Hernandez, Ivonne Angelica; Major, Paul; Flores-Mir, Carlos

2017-07-01

Breast feeding has been suggested as a potential protective factor against childhood snoring and sleep disordered breathing (SDB). SDB can have major health consequences. The objective of this systematic review is to synthesise the available literature concerning any potential association between infant feeding methods and SDB in young children. Five electronic databases were searched. All searches were inclusive until August 5, 2016. Two authors independently reviewed potentially relevant articles for eligibility. Any prospective or retrospective study, case-control study, cohort study, clinical trial, and cross-sectional study that evaluated the association between infant feeding methods and SDB were included. Data on study design, aim of study, sample size, study population, assessment tool, infant feeding methods, and outcome measures were extracted. Nine studies fulfilled the criteria to be finally included in this review, only cohorts and cross-sectional studies were identified. While seven of the selected studies reported a statistically significant association between breast feeding and reduced risk of SDB, the remaining two studies did not report any association. The main methodological limitation was high heterogeneity in the diagnostic criteria and assessment tools to identify SDB and limited data collection on infant feeding methods. The current evidence may point to a protective association, however, as uncertainty is moderate, any suggestion that breast feeding may or may not decrease the risk of SDB is currently unwarranted. More research on the topic is required to resolve some of the contradictions between included studies. © 2017 John Wiley & Sons Ltd.

Mortality from motorcycle crashes: the baby-boomer cohort effect.

PubMed

Puac-Polanco, Victor; Keyes, Katherine M; Li, Guohua

2016-12-01

Motorcyclists are known to be at substantially higher risk per mile traveled of dying from crashes than car occupants. In 2014, motorcycling made up less than 1 % of person-miles traveled but 13 % of the total mortality from motor-vehicle crashes in the United States. We assessed the cohort effect of the baby-boomers (i.e., those born between 1946 and 1964) in motorcycle crash mortality from 1975 to 2014 in the United States. Using mortality data for motorcycle occupants from the Fatality Analysis Reporting System, we performed an age-period-cohort analysis using the multiphase method and the intrinsic estimator method. Baby-boomers experienced the highest mortality rates from motorcycle crashes at age 20-24 years and continued to experience excess mortality after age 40 years. After removing the effects of age and period, the estimated mortality risk from motorcycle crashes for baby-boomers was 48 % higher than that of the referent cohort (those born between 1930 and 1934, rate ratio 1.48; 95 % CI: 1.01, 2.18). Results from the multiphase method and the intrinsic estimator method were consistent. The baby-boomers have experienced significantly higher mortality from motorcycle crashes than other birth cohorts. To reduce motorcycle crash mortality, intervention programs specifically tailored for the baby-boomer generation are warranted.

Effects of etomidate on complications related to intubation and on mortality in septic shock patients treated with hydrocortisone: a propensity score analysis

PubMed Central

2012-01-01

Introduction Endotracheal intubation in the ICU is associated with a high incidence of complications. Etomidate use is debated in septic shock because it increases the risk of critical illness-related corticosteroid insufficiency, which may impact outcome. We hypothesized that hydrocortisone, administered in all septic shock cases in our ICU, may counteract some negative effects of etomidate. The aim of our study was to compare septic shock patients who received etomidate versus another induction drug both for short-term safety and for long-term outcomes. Methods A single-center observational study was carried out in septic shock patients, treated with hydrocortisone and intubated within the first 48 hours of septic shock. Co-primary end points were life-threatening complications incidence occurring within the first hour after intubation and mortality during the ICU stay. Statistical analyses included unmatched and matched cohorts using a propensity score analysis. P < 0.05 was considered significant. Results Sixty patients in the etomidate cohort and 42 patients in the non-etomidate cohort were included. Critical illness-related corticosteroid insufficiency was 79% in the etomidate cohort and 52% in the non-etomidate cohort (P = 0.01). After intubation, life-threatening complications occurred in 36% of the patients whatever the cohort. After adjustment with propensity score analysis, etomidate was a protective factor for death in the ICU both in unmatched (hazard ratio, 0.33 (0.15 to 0.75); P < 0.01)) and matched cohorts (hazard ratio, 0.33 (0.112 to 0.988); P = 0.04). Conclusion In septic shock patients treated with hydrocortisone, etomidate did not decrease life-threatening complications following intubation, but when associated with hydrocortisone it also did not impair outcome. PMID:23171852

Time-trends in the prescribing of gastroprotective agents to primary care patients initiating low-dose aspirin or non-steroidal anti-inflammatory drugs: a population-based cohort study

PubMed Central

Warlé-van Herwaarden, Margaretha F; Koffeman, Aafke R; Valkhoff, Vera E; ’t Jong, Geert W; Kramers, Cornelis; Sturkenboom, Miriam C; De Smet, Peter A G M

2015-01-01

Aims Low-dose aspirin (LDA) and non-steroidal-anti-inflammatory drugs (NSAIDs) both increase the risk of upper gastrointestinal events (UGIEs). In the Netherlands, recommendations regarding the prescription of gastroprotective agents (GPAs) in LDA users were first issued in 2009 in the HARM-Wrestling consensus. National guidelines on gastroprotective strategies (GPSs) in NSAID users were issued in the first part of the preceding. The aim of the present study was to examine time-trends in GPSs in patients initiating LDA and those initiating NSAIDs between 2000 and 2012. Methods Within a large electronic primary healthcare database, two cohorts were selected: (i) patients newly prescribed LDA and (ii) patients newly prescribed NSAIDs between 2000 and 2012. Patients who had been prescribed a GPA in the previous six months were excluded. For both cohorts, patients’ risk of a UGIE was classified as low, moderate or high, based on the HARM-Wrestling consensus, and the presence of an adequate GPSwas determined. Results A total of 37 578 patients were included in the LDA cohort and 352 025 patients in the NSAID cohort. In both cohorts, an increase in GPSs was observed over time, but prescription of GPAs was lower in the LDA cohort. By 2012, an adequate GPS was present in 31.8% of high-risk LDA initiators, vs. 48.0% of high-risk NSAID initiators. Conclusions Despite a comparable risk of UGIEs, GPSs are prescribed less in high-risk LDA initiators than in high-risk NSAID initiators. For both groups of patients, there is still room for improvement in guideline adherence. PMID:25777983

Safety and Efficacy of Dolutegravir in Treatment-Experienced Subjects With Raltegravir-Resistant HIV Type 1 Infection: 24-Week Results of the VIKING Study

PubMed Central

Eron, Joseph J.; Clotet, Bonaventura; Durant, Jacques; Katlama, Christine; Kumar, Princy; Lazzarin, Adriano; Poizot-Martin, Isabelle; Richmond, Gary; Soriano, Vincent; Ait-Khaled, Mounir; Fujiwara, Tamio; Huang, Jenny; Min, Sherene; Vavro, Cindy; Yeo, Jane; Walmsley, Sharon L.; Cox, Joseph; Reynes, Jacques; Morlat, Philippe; Vittecoq, Daniel; Livrozet, Jean-Michel; Fernández, Pompeyo Viciana; Gatell, Jose M.; DeJesus, Edwin; DeVente, Jerome; Lalezari, Jacob P.; McCurdy, Lewis H.; Sloan, Louis A.; Young, Benjamin; LaMarca, Anthony; Hawkins, Trevor

2013-01-01

Background. Dolutegravir (DTG; S/GSK1349572), a human immunodeficiency virus type 1 (HIV-1) integrase inhibitor, has limited cross-resistance to raltegravir (RAL) and elvitegravir in vitro. This phase IIb study assessed the activity of DTG in HIV-1–infected subjects with genotypic evidence of RAL resistance. Methods. Subjects received DTG 50 mg once daily (cohort I) or 50 mg twice daily (cohort II) while continuing a failing regimen (without RAL) through day 10, after which the background regimen was optimized, when feasible, for cohort I, and at least 1 fully active drug was mandated for cohort II. The primary efficacy end point was the proportion of subjects on day 11 in whom the plasma HIV-1 RNA load decreased by ≥0.7 log10 copies/mL from baseline or was <400 copies/mL. Results. A rapid antiviral response was observed. More subjects achieved the primary end point in cohort II (23 of 24 [96%]), compared with cohort I (21 of 27 [78%]) at day 11. At week 24, 41% and 75% of subjects had an HIV-1 RNA load of <50 copies/mL in cohorts I and II, respectively. Further integrase genotypic evolution was uncommon. Dolutegravir had a good, similar safety profile with each dosing regimen. Conclusion. Dolutegravir 50 mg twice daily with an optimized background provided greater and more durable benefit than the once-daily regimen. These data are the first clinical demonstration of the activity of any integrase inhibitor in subjects with HIV-1 resistant to RAL. PMID:23225901

Biomarkers Predictive of Exacerbations in the SPIROMICS and COPDGene Cohorts

PubMed Central

Keene, Jason D.; Jacobson, Sean; Kechris, Katerina; Kinney, Gregory L.; Foreman, Marilyn G.; Doerschuk, Claire M.; Make, Barry J.; Curtis, Jeffrey L.; Rennard, Stephen I.; Barr, R. Graham; Bleecker, Eugene R.; Kanner, Richard E.; Kleerup, Eric C.; Hansel, Nadia N.; Woodruff, Prescott G.; Han, MeiLan K.; Paine, Robert; Martinez, Fernando J.; O’Neal, Wanda K.

2017-01-01

Rationale: Chronic obstructive pulmonary disease exacerbations are associated with disease progression, higher healthcare cost, and increased mortality. Published predictors of future exacerbations include previous exacerbation, airflow obstruction, poor overall health, home oxygen use, and gastroesophageal reflux. Objectives: To determine the value of adding blood biomarkers to clinical variables to predict exacerbations. Methods: Subjects from the SPIROMICS (Subpopulations and Intermediate Outcomes Measures in COPD Study) (n = 1,544) and COPDGene (Genetic Epidemiology of COPD) (n = 602) cohorts had 90 plasma or serum candidate proteins measured on study entry using Myriad-RBM multiplex panels. We defined total exacerbations as subject-reported worsening in respiratory health requiring therapy with corticosteroids and/or antibiotics, and severe exacerbations as those leading to hospitalizations or emergency room visits. We assessed retrospective exacerbations during the 12 months before enrollment and then documented prospective exacerbations in each cohort. Exacerbations were modeled for biomarker associations with negative binomial regression including clinical covariates (age, sex, percent predicted FEV1, self-reported gastroesophageal reflux, St. George’s Respiratory Questionnaire score, smoking status). We used the Stouffer-Liptak test to combine P values for metaanalysis. Measurements and Main Results: Between the two cohorts, 3,471 total exacerbations (1,044 severe) were reported. We identified biomarkers within each cohort that were significantly associated with a history of exacerbation and with a future exacerbation, but there was minimal replication between the cohorts. Although established clinical features were predictive of exacerbations, of the blood biomarkers only decorin and α2-macroglobulin increased predictive value for future severe exacerbations. Conclusions: Blood biomarkers were significantly associated with the occurrence of exacerbations but were not robust between cohorts and added little to the predictive value of clinical covariates for exacerbations. PMID:27579823

Telomere Shortening and Associated Chromosomal Instability in Peripheral Blood Lymphocytes of Patients With Hodgkin's Lymphoma Prior to Any Treatment Are Predictive of Second Cancers

DOE Office of Scientific and Technical Information (OSTI.GOV)

M'kacher, Radhia; Bennaceur-Griscelli, Annelise; Girinsky, Theodore

Purpose: To investigate a potential link between telomere length, chromosomal instability, and the advent of a second cancer (SC) in patients with Hodgkin's lymphoma (HL), who are known to be at risk for SCs. This study was premised on the finding that telomere dysfunction and DNA repair pathways were related to many pathologic conditions. Methods and Materials: Three cohorts of patients with HL were studied: 73 who were prospectively followed >5 years after diagnosis (prospective HL cohort), 28 who developed a SC (SC HL cohort), and 18 long-term survivors with no evidence of disease or complication since their initial treatmentmore » (NED HL cohort). Telomere length was analyzed by a telomeric restriction fragment assay in peripheral blood lymphocytes. Thirty healthy donors and 70 patients with a newly diagnosed solid tumor were the control population. Results: Compared with controls, patients from the prospective HL cohort, before any treatment, showed age-independent shorter telomeres (mean, 8.3 vs. 11.7 kb in healthy donors; <6 kb in 18% in HL patients), increased spontaneous chromosomal abnormalities, and increased in vitro radiation sensitivity (p < 10{sup -4} each). After treatment, telomere shortening was associated with cytogenetic profiles characterized by the persistence of complex chromosomal rearrangement and clonal aberrations. Moreover, the two cases of SC in the prospective HL patients had short telomeres and CCR initially. In addition, the SC HL cohort was characterized by markedly short telomeres (6.6 vs. 9.7 kb in the NED HL cohort), the presence of complex chromosome rearrangements, and increased in vitro radiation sensitivity. Conclusions: An intimate relationship between pre-treatment telomere shortening, chromosomal instability, radiation sensitivity and occurrence of SC was found in HL patients.« less

[Validity of self-reported metabolic syndrome components in a cohort study].

PubMed

Fernández-Montero, Alejandro; Beunza, Juan J; Bes-Rastrollo, Maira; Barrio, María T; de la Fuente-Arrillaga, Carmen; Moreno-Galarraga, Laura; Martínez-González, Miguel A

2011-01-01

To assess the accuracy of self-reported data needed to constitute the metabolic syndrome in the University of Navarra Follow-Up [Seguimiento Universidad de Navarra (SUN)] cohort. The SUN project is a multi-purpose prospective cohort, formed by more than 20,000 university graduates, followed-up using surface mail questionnaires every 2 years. In a sample of 287 cohort participants, self-reported data on the criteria needed to define the metabolic syndrome (waist circumference, blood pressure, triglycerides, high-density lipoprotein-cholesterol and glucose) were compared with the same biometric data obtained by blood tests or measured by trained medical staff. Intra-class correlation coefficients with 95% confidence intervals (95% CI), relative mean error and agreement limits according to the method proposed by Bland and Altman were calculated for each variable studied. High intraclass correlations were found for the values of waist circumference (r=0.86, 95% CI: 0.80-0.90) and triglycerides (r=0.71, 95%CI: 0.61-0.79). Moderate intraclass correlations were found (between 0.46 and 0.63) for the other factors. Relative mean errors were always<2.5%, and >91% of values were within the limits of agreement for all variables. The results suggest that self-declared data on the criteria of metabolic syndrome obtained in the SUN cohort, though with some caution, are sufficiently accurate to be used in epidemiological studies. Copyright © 2010 SESPAS. Published by Elsevier Espana. All rights reserved.

Comparison of 2 Radiographic Techniques for Measurement of Tibiofemoral Joint Space Width.

PubMed

Mehta, Nabil; Duryea, Jeffrey; Badger, Gary J; Akelman, Matthew R; Jones, Morgan H; Spindler, Kurt P; Fleming, Braden C

2017-09-01

No consensus is available regarding the best method for measuring tibiofemoral joint space width (JSW) on radiographs to quantify joint changes after injury. Studies that track articular cartilage thickness after injury frequently use patients' uninjured contralateral knees as controls, although the literature supporting this comparison is limited. (1) To compare JSW measurements using 2 established measurement techniques in healthy control participants and (2) to determine whether the mean JSW of the uninjured contralateral knee in a cohort with anterior cruciate ligament (ACL) reconstruction is different from that obtained from a true control population. Cohort study (diagnosis); Level of evidence, 2. Medial and lateral JSWs were measured on standardized, bilateral, semiflexed metatarsophalangeal positioning, posteroanterior radiographs of 60 healthy individuals (26 females; mean ± SD age, 25 ± 6.2 years; no history of knee injury) via 2 published techniques: a computerized surface-delineation method (surface-fit method) and a manual digitization method (midpoint method). Bland-Altman method was used to examine the agreement between JSW measurements obtained with the 2 methods and to examine the agreement between measurements obtained on left and right knees within a participant for each measurement method. Within- and between-participant variance components and intraclass correlation coefficients (ICCs) were computed for JSW measurements corresponding to each method. Two-sample t tests were used to compare the surface-fit method measurements of mean JSW of the true control group (n = 60) with the previously published mean JSW measurements from the Multicenter Orthopaedics Outcomes Network (MOON) nested cohort of 262 contralateral uninjured knees 2 to 3 years after ACL reconstruction. For JSW in the medial compartment, the surface-fit method had lower within-participant interknee variability (σ 2 within , 0.064; 95% CI, 0.04-0.09) compared with the midpoint method (σ 2 within , 0.28; 95% CI, 0.20-0.43) and a higher ICC (0.93 vs 0.65; P < .001). Lateral JSW values were similar for the surface-fit method (σ 2 within , 0.27; 95% CI, 0.18-0.43) and the midpoint method (σ 2 within , 0.20; 95% CI, 0.14-0.31), with ICCs of 0.75 and 0.77, respectively ( P = .80). With the surface-fit method, mean JSW measurements of the medial and lateral compartments of a control population were not significantly different from the contralateral uninjured knees of patients after ACL reconstruction. For measuring medial JSW, the surface-fit method was less variable across knees within a participant than the midpoint method, as evidenced by larger ICCs and lower interknee variability. For measuring lateral JSW, the 2 methods were similar. The JSW measurements of uninjured contralateral knees of patients with ACL reconstruction at 2 to 3 years postsurgery were not significantly different from those of a cohort of healthy control participants. Future work should be performed to demonstrate the validity of these methods for documenting change over time in the ACL-reconstructed knee.

Halo-Vest Immobilization in Elderly Odontoid Fracture Patients: Evolution in Treatment Modality and In-Hospital Outcomes.

PubMed

DePasse, J Mason; Palumbo, Mark A; Ahmed, Abdul-Kareem; Adams, Charles A; Daniels, Alan H

2017-11-01

Retrospective cohort study. To evaluate the utilization and effectiveness of halo-vest (HV) immobilization for type II odontoid fractures from 2004 to 2014. Controversy persists regarding the optimal treatment method for odontoid fractures in the elderly. Management options include immobilization in a cervical orthosis, HV immobilization, and operative intervention. Over the past decade, high mortality and morbidity rates have been reported following HV immobilization in this patient population. In a retrospective study, patient demographics, presentation, Charlson comorbidity index, treatment method, and outcome data for patients over 65 who had suffered type II odontoid fractures from 2004 to 2014 were compared with a historical cohort from 1997 to 2004. One hundred twenty-six patients met inclusion criteria. The mean age was 82.7±8.8 compared with 80.7±0.9 in the 1997-2004 cohort. The in-hospital mortality rate from 2004 to 2014 was 11.1% (14/126) compared with 31% in the historical cohort, and 10 (7.9%) patients were treated with HV compared with 49%. Mortality in the HV group was higher than the surgical group (P=0.01) but no different from the orthosis group (P=0.63).There were no differences in injury severity score, Charlson comorbidity index, or complications between treatment groups. Over the past decade, HV use for elderly odontoid fractures has decreased at our institution. Mortality and morbidity of elderly patients treated with HV has also decreased. These findings are likely the result of improved patient selection and greater attention to respiratory care. This study demonstrates that HV immobilization of odontoid fractures in elderly patients can be as safe as cervical orthosis treatment in select patients.

Association between mothers’ screening uptake and daughters’ HPV vaccination: a quasi-experimental study on the effect of an active invitation campaign

PubMed Central

Baldacchini, Flavia; Campari, Cinzia; Perilli, Cinzia; Pascucci, Maria Grazia; Finarelli, Alba Carola; Moscara, Luigi; Rossi, Paolo Giorgi

2017-01-01

Objectives In Emilia-Romagna, the Human Papillomavirus (HPV) vaccination campaign started in 2008 offering free vaccines for 1996 and 1997 cohorts. Systematic active invitation was implemented for the 1997 cohort. Our study aimed at measuring the impact of the active invitation campaign on HPV vaccine coverage and on coverage inequalities in 11-year-old girls. Second, we evaluated the effect of the HPV vaccination campaign on participation in cervical cancer screening by mothers of target girls. Methods We collected information on vaccination status for girls residing in Reggio Emilia in 2008 and mothers’ screening history, before and after the 2008 vaccination campaign. Log-binomial regression models were performed to estimate Relative Risk (RR) and 95% confidence intervals (CIs) of being vaccinated as regarded citizenship, siblings, mothers’ education, marital status and screening history, stratified by birth cohort. We also calculated RR of receiving a Pap test after the vaccination campaign as regarded education, daughter’s cohort and mothers’ decision to have their daughter vaccinated. Interaction between education and cohort in mothers overdue for Pap testing was calculated. Results Vaccination coverage was 46.3% for the uninvited cohort (1046/2260) and 77.9% for the invited cohort (1798/2307). In the uninvited cohort, daughters’ vaccination showed association with mothers’ education (8 to 11 years of education vs. graduated mothers, RR 1.61 95% CI 1.14–2.28), citizenship (foreigners vs. Italians, RR 0.45 95% CI 0.37–0.56) and screening history (regular vs. non-participant; RR 1.72 95% CI 1.26–2.36). In the invited cohort, only a slight association with screening history persisted (regular vs. non-participant; RR 1.20 95% CI 1.04–1.40). Highly educated under-screened mothers of the invited cohort showed a higher probability of receiving a Pap test after the vaccination campaign period (RR 1.27 95% CI 1.04–1.56) compared with those not invited, Conclusion Active invitation could increase overall HPV immunisation coverage and reduce socio-demographic inequalities and the association with mothers’ screening participation. PMID:28951407

Mortality in a Combined Cohort of Uranium Enrichment Workers

PubMed Central

Yiin, James H.; Anderson, Jeri L.; Daniels, Robert D.; Bertke, Stephen J.; Fleming, Donald A.; Tollerud, David J.; Tseng, Chih-Yu; Chen, Pi-Hsueh; Waters, Kathleen M.

2017-01-01

Objective To examine the patterns of cause-specific mortality and relationship between internal exposure to uranium and specific causes in a pooled cohort of 29,303 workers employed at three former uranium enrichment facilities in the United States with follow-up through 2011. Methods Cause-specific standardized mortality ratios (SMRs) for the full cohort were calculated with the U.S. population as referent. Internal comparison of the dose-response relation between selected outcomes and estimated organ doses was evaluated using regression models. Results External comparison with the U.S. population showed significantly lower SMRs in most diseases in the pooled cohort. Internal comparison showed positive associations of absorbed organ doses with multiple myeloma, and to a lesser degree with kidney cancer. Conclusion In general, these gaseous diffusion plant workers had significantly lower SMRs than the U.S. population. The internal comparison however, showed associations between internal organ doses and diseases associated with uranium exposure in previous studies. PMID:27753121

Perceived job insecurity as a risk factor for incident coronary heart disease: systematic review and meta-analysis

PubMed Central

Nyberg, Solja T; Batty, G David; Jokela, Markus; Heikkilä, Katriina; Fransson, Eleonor I; Alfredsson, Lars; Bjorner, Jakob B; Borritz, Marianne; Burr, Hermann; Casini, Annalisa; Clays, Els; De Bacquer, Dirk; Dragano, Nico; Elovainio, Marko; Erbel, Raimund; Ferrie, Jane E; Hamer, Mark; Jöckel, Karl-Heinz; Kittel, France; Knutsson, Anders; Koskenvuo, Markku; Koskinen, Aki; Lunau, Thorsten; Madsen, Ida E H; Nielsen, Martin L; Nordin, Maria; Oksanen, Tuula; Pahkin, Krista; Pejtersen, Jan H; Pentti, Jaana; Rugulies, Reiner; Salo, Paula; Shipley, Martin J; Siegrist, Johannes; Steptoe, Andrew; Suominen, Sakari B; Theorell, Töres; Toppinen-Tanner, Salla; Väänänen, Ari; Vahtera, Jussi; Westerholm, Peter J M; Westerlund, Hugo; Slopen, Natalie; Kawachi, Ichiro; Singh-Manoux, Archana; Kivimäki, Mika

2013-01-01

Objective To determine the association between self reported job insecurity and incident coronary heart disease. Design A meta-analysis combining individual level data from a collaborative consortium and published studies identified by a systematic review. Data sources We obtained individual level data from 13 cohort studies participating in the Individual-Participant-Data Meta-analysis in Working Populations Consortium. Four published prospective cohort studies were identified by searches of Medline (to August 2012) and Embase databases (to October 2012), supplemented by manual searches. Review methods Prospective cohort studies that reported risk estimates for clinically verified incident coronary heart disease by the level of self reported job insecurity. Two independent reviewers extracted published data. Summary estimates of association were obtained using random effects models. Results The literature search yielded four cohort studies. Together with 13 cohort studies with individual participant data, the meta-analysis comprised up to 174 438 participants with a mean follow-up of 9.7 years and 1892 incident cases of coronary heart disease. Age adjusted relative risk of high versus low job insecurity was 1.32 (95% confidence interval 1.09 to 1.59). The relative risk of job insecurity adjusted for sociodemographic and risk factors was 1.19 (1.00 to 1.42). There was no evidence of significant differences in this association by sex, age (<50 v ≥50 years), national unemployment rate, welfare regime, or job insecurity measure. Conclusions The modest association between perceived job insecurity and incident coronary heart disease is partly attributable to poorer socioeconomic circumstances and less favourable risk factor profiles among people with job insecurity. PMID:23929894

The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS): Study Design and Methods

EPA Science Inventory

The Near-road EXposures and effects of urban air pollutants Study (NEXUS) was designed to examine the relationship between near-roadway exposures to air pollutants and respiratory outcomes in a cohort of asthmatic children who live close to major roadways in Detroit, Michigan USA...

Methods of analysis of enteropathogen infection in the MAL-ED Cohort Study.

PubMed

Platts-Mills, James A; McCormick, Benjamin J J; Kosek, Margaret; Pan, William K; Checkley, William; Houpt, Eric R

2014-11-01

Studies of diarrheal etiology in low- and middle-income countries have typically focused on children presenting with severe symptoms to health centers and thus are best equipped to describe the pathogens capable of leading to severe diarrheal disease. The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study was designed to evaluate, via intensive community surveillance, the hypothesis that repeated exposure to enteropathogens has a detrimental effect on growth, vaccine response, and cognitive development, which are the primary outcome measures for this study. In the setting of multiple outcomes of interest, a longitudinal cohort design was chosen. Because many or even the majority of enteric infections are asymptomatic, the collection of asymptomatic surveillance stools was a critical element. However, capturing diarrheal stools additionally allowed for the determination of the principle causes of diarrhea at the community level as well as for a comparison between those enteropathogens associated with diarrhea and those that are associated with poor growth, diminished vaccine response, and impaired cognitive development. Here, we discuss the analytical methods proposed for the MAL-ED study to determine the principal causes of diarrhea at the community level and describe the complex interplay between recurrent exposure to enteropathogens and these critical long-term outcomes. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Comparison of Fecal Collection Methods for Microbiota Studies in Bangladesh

PubMed Central

Chen, Jun; Kibriya, Muhammad G.; Chen, Yu; Islam, Tariqul; Eunes, Mahbubul; Ahmed, Alauddin; Naher, Jabun; Rahman, Anisur; Amir, Amnon; Shi, Jianxin; Abnet, Christian C.; Nelson, Heidi; Knight, Rob; Chia, Nicholas; Ahsan, Habibul; Sinha, Rashmi

2017-01-01

ABSTRACT To our knowledge, fecal microbiota collection methods have not been evaluated in low- and middle-income countries. Therefore, we evaluated five different fecal sample collection methods for technical reproducibility, stability, and accuracy within the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh. Fifty participants from the HEALS provided fecal samples in the clinic which were aliquoted into no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test (FOBT) cards, and fecal immunochemical test (FIT) tubes. Half of the aliquots were frozen immediately at −80°C (day 0) and the remaining samples were left at ambient temperature for 96 h and then frozen (day 4). Intraclass correlation coefficients (ICC) were calculated for the relative abundances of the top three phyla, for two alpha diversity measures, and for four beta diversity measures. The duplicate samples had relatively high ICCs for technical reproducibility at day 0 and day 4 (range, 0.79 to 0.99). The FOBT card and samples preserved in RNAlater and 95% ethanol had the highest ICCs for stability over 4 days. The FIT tube had lower stability measures overall. In comparison to the “gold standard” method using immediately frozen fecal samples with no solution, the ICCs for many of the microbial metrics were low, but the rank order appeared to be preserved as seen by the Spearman correlation. The FOBT cards, 95% ethanol, and RNAlater were effective fecal preservatives. These fecal collection methods are optimal for future cohort studies, particularly in low- and middle-income countries. IMPORTANCE The collection of fecal samples in prospective cohort studies is essential to provide the opportunity to study the effect of the human microbiota on numerous health conditions. However, these collection methods have not been adequately tested in low- and middle-income countries. We present estimates of technical reproducibility, stability at ambient temperature for 4 days, and accuracy comparing a “gold standard” for fecal samples in no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test cards, and fecal immunochemical test tubes in a study conducted in Bangladesh. Fecal occult blood test cards and fecal samples stored in 95% ethanol or RNAlater adequately preserve fecal samples in this setting. Therefore, new studies in low- and middle-income countries should include collection of fecal samples using fecal occult blood test cards, 95% ethanol, or RNAlater for prospective cohort studies. PMID:28258145

Increased risk of stroke in contact dermatitis patients

PubMed Central

Chang, Wei-Lun; Hsu, Min-Hsien; Lin, Cheng-Li; Chan, Po-Chi; Chang, Ko-Shih; Lee, Ching-Hsiao; Hsu, Chung-Yi; Tsai, Min-Tein; Yeh, Chung-Hsin; Sung, Fung-Chang

2017-01-01

Abstract Dermatologic diseases are not traditional risk factors of stroke, but recent studies show atopic dermatitis, psoriasis, and bullous skin disease may increase the risk of stroke and other cardiovascular diseases. No previous studies have focused on the association between contact dermatitis and stroke. We established a cohort comprised of 48,169 contact dermatitis patients newly diagnosed in 2000–2003 and 96,338 randomly selected subjects without the disorder, frequency matched by sex, age, and diagnosis year, as the comparison cohort. None of them had a history of stroke. Stroke incidence was assessed by the end of 2011 for both cohorts. The incidence stroke was 1.1-fold higher in the contact dermatitis cohort than in the comparison cohort (5.93 vs 5.37 per 1000 person-years, P < 0.01). The multivariable Cox method analyzed adjusted hazard ratios (aHRs) were 1.12 (95% confidence interval [CI], 1.05–1.19) for all stroke types and 1.12 (95% CI, 1.05–1.20) for ischemic stroke and 1.11 (95% CI, 0.94–1.30) for hemorrhagic stroke. The age-specific aHR of stroke for contact dermatitis cohort increased with age, from 1.14 (95% CI, 1.03–1.27) for 65 to 74 years; to 1.27 (95% CI, 1.15–1.42) for 75 years and older. The aHR of stroke were 1.16 (95% CI, 1.07–1.27) and 1.09 (95% CI, 1.00–1.18) for men and women, respectively. This study suggests that patients with contact dermatitis were at a modestly increased risk of stroke, significant for ischemic stroke but not for hemorrhagic stroke. Comorbidity, particularly hypertension, increased the hazard of stroke further. PMID:28272195

A new algorithm to build bridges between two patient-reported health outcome instruments: the MOS SF-36® and the VR-12 Health Survey.

PubMed

Selim, Alfredo; Rogers, William; Qian, Shirley; Rothendler, James A; Kent, Erin E; Kazis, Lewis E

2018-04-19

To develop bridging algorithms to score the Veterans Rand-12 (VR-12) scales for comparability to those of the SF-36® for facilitating multi-cohort studies using data from the National Cancer Institute Surveillance, Epidemiology, and End Results Program (SEER) linked to Medicare Health Outcomes Survey (MHOS), and to provide a model for minimizing non-statistical error in pooled analyses stemming from changes to survey instruments over time. Observational study of MHOS cohorts 1-12 (1998-2011). We modeled 2-year follow-up SF-36 scale scores from cohorts 1-6 based on baseline SF-36 scores, age, and gender, yielding 100 clusters using Classification and Regression Trees. Within each cluster, we averaged follow-up SF-36 scores. Using the same cluster specifications, expected follow-up SF-36 scores, based on cohorts 1-6, were computed for cohorts 7-8 (where the VR-12 was the follow-up survey). We created a new criterion validity measure, termed "extensibility," calculated from the square root of the mean square difference between expected SF-36 scale averages and observed VR-12 item score from cohorts 7-8, weighted by cluster size. VR-12 items were rescored to minimize this quantity. Extensibility of rescored VR-12 items and scales was considerably improved from the "simple" scoring method for comparability to the SF-36 scales. The algorithms are appropriate across a wide range of potential subsamples within the MHOS and provide robust application for future studies that span the SF-36 and VR-12 eras. It is possible that these surveys in a different setting outside the MHOS, especially in younger age groups, could produce somewhat different results.

How Computer Literacy and Socioeconomic Status Affect Attitudes Toward a Web-Based Cohort: Results From the NutriNet-Santé Study

PubMed Central

Méjean, Caroline; Andreeva, Valentina A; Kesse-Guyot, Emmanuelle; Fassier, Philippine; Galan, Pilar; Hercberg, Serge; Touvier, Mathilde

2015-01-01

Background In spite of the growing literature in the field of e-epidemiology, clear evidence about computer literacy or attitudes toward respondent burden among e-cohort participants is largely lacking. Objective We assessed the computer and Internet skills of participants in the NutriNet-Santé Web-based cohort. We then explored attitudes toward the study demands/respondent burden according to levels of computer literacy and sociodemographic status. Methods Self-reported data from 43,028 e-cohort participants were collected in 2013 via a Web-based questionnaire. We employed unconditional logistic and linear regression analyses. Results Approximately one-quarter of participants (23.79%, 10,235/43,028) reported being inexperienced in terms of computer use. Regarding attitudes toward participant burden, women tended to be more favorable (eg, “The overall website use is easy”) than were men (OR 0.65, 95% CI 0.59-0.71, P<.001), whereas better educated participants (>12 years of schooling) were less likely to accept the demands associated with participation (eg, “I receive questionnaires too often”) compared to their less educated counterparts (OR 1.62, 95% CI 1.48-1.76, P<.001). Conclusions A substantial proportion of participants had low computer/Internet skills, suggesting that this does not represent a barrier to participation in Web-based cohorts. Our study also suggests that several subgroups of participants with lower computer skills (eg, women or those with lower educational level) might more readily accept the demands associated with participation in the Web cohort. These findings can help guide future Web-based research strategies. PMID:25648178

Development and validation of the Surgical Outcome Risk Tool (SORT)

PubMed Central

Protopapa, K L; Simpson, J C; Smith, N C E; Moonesinghe, S R

2014-01-01

Background Existing risk stratification tools have limitations and clinical experience suggests they are not used routinely. The aim of this study was to develop and validate a preoperative risk stratification tool to predict 30-day mortality after non-cardiac surgery in adults by analysis of data from the observational National Confidential Enquiry into Patient Outcome and Death (NCEPOD) Knowing the Risk study. Methods The data set was split into derivation and validation cohorts. Logistic regression was used to construct a model in the derivation cohort to create the Surgical Outcome Risk Tool (SORT), which was tested in the validation cohort. Results Prospective data for 19 097 cases in 326 hospitals were obtained from the NCEPOD study. Following exclusion of 2309, details of 16 788 patients were analysed (derivation cohort 11 219, validation cohort 5569). A model of 45 risk factors was refined on repeated regression analyses to develop a model comprising six variables: American Society of Anesthesiologists Physical Status (ASA-PS) grade, urgency of surgery (expedited, urgent, immediate), high-risk surgical specialty (gastrointestinal, thoracic, vascular), surgical severity (from minor to complex major), cancer and age 65 years or over. In the validation cohort, the SORT was well calibrated and demonstrated better discrimination than the ASA-PS and Surgical Risk Scale; areas under the receiver operating characteristic (ROC) curve were 0·91 (95 per cent c.i. 0·88 to 0·94), 0·87 (0·84 to 0·91) and 0·88 (0·84 to 0·92) respectively (P < 0·001). Conclusion The SORT allows rapid and simple data entry of six preoperative variables, and provides a percentage mortality risk for individuals undergoing surgery. PMID:25388883

Exhaustively Characterizing a Patient Cohort by Prevalence of EMR Facts: a Generalized, Vendor-Agnostic Method for Quality Control and Research.

PubMed

Alex F, Bokov; Olin, Gail P; Bos, Angela; Tirado-Ramos, Alfredo; Kittrell, Pamela; Jackson, Carlayne

2017-01-01

We present a method for rapidly ranking all distinct facts in an electronic medical record (EMR) system by howover-represented or under-represented they are in a patient cohort of interest relative to some larger referencepopulation of patients in the same EMR. We have implemented this method as a plugin for i2b2, the open sourcedata warehouse platform widely used in research health informatics. Our method is highly flexible in terms of whatmedical terminologies it supports and is vendor-independent thanks to leveraging the i2b2 star schema rather thanany one specific EMR. It can be applied to a wide range of informatics problems including finding healthdisparities, searching for variables to include in a risk calculator or computable phenotype, detection ofcomorbidities, discovery of adverse drug reactions. The case study we present here uses this software to findunlabeled flowsheets for patients suffering from amyotrophic lateral sclerosis.

Research designs and making causal inferences from health care studies.

PubMed

Flannelly, Kevin J; Jankowski, Katherine R B

2014-01-01

This article summarizes the major types of research designs used in healthcare research, including experimental, quasi-experimental, and observational studies. Observational studies are divided into survey studies (descriptive and correlational studies), case-studies and analytic studies, the last of which are commonly used in epidemiology: case-control, retrospective cohort, and prospective cohort studies. Similarities and differences among the research designs are described and the relative strength of evidence they provide is discussed. Emphasis is placed on five criteria for drawing causal inferences that are derived from the writings of the philosopher John Stuart Mill, especially his methods or canons. The application of the criteria to experimentation is explained. Particular attention is given to the degree to which different designs meet the five criteria for making causal inferences. Examples of specific studies that have used various designs in chaplaincy research are provided.

Feasibility of cohort studies in Estonia

PubMed Central

Innos, K.; Rahu, M.; Rahu, K.

1999-01-01

OBJECTIVES: To describe the methodology and feasibility of follow up for vital status in retrospective cohort studies in Estonia. METHODS: A cohort of 7412 workers who had been employed at two factories in Tallinn between 1946 and 1988 was followed up for vital status from the date of first employment until death, emigration, or the end of the study, 31 December 1995, whichever occurred first. The cohort was electronically linked with the National Population Registry of Estonia that was created in 1992 and includes personal identification numbers of Estonian citizens and residents, and the Mortality Database that contains information from death certificates issued in 1983-95. A manual search was carried out on several non-computerised population data sources and archives. RESULTS: By 31 December 1995, the vital status of 6780 (91.5%) subjects could be traced (4495 (60.6%) subjects were alive, 1993 (26.9%) had died, and 292 (3.9%) had emigrated). Analysis by calendar period of leaving work showed that the proportion of subjects traced was lowest in the group of workers who had left work between 1946 and 1955 (58.4%), especially those whose age at leaving work was < 30 (53.2%) or > 60 years (42.3%). Among subjects who left work in 1956-65, 1966-75, and 1976-88, the follow up rate was 84.7%, 94.6%, and 98.2%, respectively. CONCLUSIONS: The findings, which are especially important for occupational epidemiology, confirm the feasibility of conducting retrospective cohort studies in Estonia. Most of the issues discussed in the paper apply to other former Soviet countries.   PMID:10472323

[Application of cohort study in cancer prevention and control].

PubMed

Dai, Min; Bai, Yana; Pu, Hongquan; Cheng, Ning; Li, Haiyan; He, Jie

2016-03-01

Cancer control is a long-term work. Cancer research and intervention really need the support of cohort study. In the recent years, more and more cohort studies on cancer control were conducted in China along with the increased ability of scientific research in China. Since 2010, Cancer Hospital, Chinese Academy of Medical Sciences, collaborated with Lanzhou University and the Worker' s Hospital of Jinchuan Group Company Limited, have carried out a large-scale cohort study on cancer, which covered a population of more than 50 000 called " Jinchang cohort". Since 2012, a National Key Public Health Project, "cancer screening in urban China" , has been conducted in Jinchang, which strengthened the Jinchang cohort study. Based on the Jinchang cohort study, historical cohort study, cross-sectional study and prospective cohort study have been conducted, which would provide a lot of evidence for the cancer control in China.

Accounting for dropout reason in longitudinal studies with nonignorable dropout.

PubMed

Moore, Camille M; MaWhinney, Samantha; Forster, Jeri E; Carlson, Nichole E; Allshouse, Amanda; Wang, Xinshuo; Routy, Jean-Pierre; Conway, Brian; Connick, Elizabeth

2017-08-01

Dropout is a common problem in longitudinal cohort studies and clinical trials, often raising concerns of nonignorable dropout. Selection, frailty, and mixture models have been proposed to account for potentially nonignorable missingness by relating the longitudinal outcome to time of dropout. In addition, many longitudinal studies encounter multiple types of missing data or reasons for dropout, such as loss to follow-up, disease progression, treatment modifications and death. When clinically distinct dropout reasons are present, it may be preferable to control for both dropout reason and time to gain additional clinical insights. This may be especially interesting when the dropout reason and dropout times differ by the primary exposure variable. We extend a semi-parametric varying-coefficient method for nonignorable dropout to accommodate dropout reason. We apply our method to untreated HIV-infected subjects recruited to the Acute Infection and Early Disease Research Program HIV cohort and compare longitudinal CD4 + T cell count in injection drug users to nonusers with two dropout reasons: anti-retroviral treatment initiation and loss to follow-up.

Markers of endothelial cell activation and immune activation are increased in patients with severe leptospirosis and associated with disease severity

USDA-ARS?s Scientific Manuscript database

Objectives: Previous studies concluded that haemorrhage is one of the most accurate prognostic factors of mortality in leptospirosis. Therefore, endothelial cell activation was investigated in relation to disease severity in severe leptospirosis. Methods: Prospective cohort study of severe leptospi...

Prospective Associations between Dietary Patterns and Cognitive Performance during Adolescence

ERIC Educational Resources Information Center

Nyaradi, Anett; Foster, Jonathan K.; Hickling, Siobhan; Li, Jianghong; Ambrosini, Gina L.; Jacques, Angela; Oddy, Wendy H.

2014-01-01

Background: The aim of the study was to investigate prospective associations between dietary patterns and cognitive performance during adolescence. Methods: Participants were sourced from the Western Australian Pregnancy Cohort (Raine) Study that includes 2868 children born between 1989 and 1992 in Perth, Western Australia. When the children were…

Examining the Intergenerational Transmission of Violence in a New Zealand Birth Cohort

ERIC Educational Resources Information Center

Fergusson, David M.; Boden, Joseph M.; Horwood, L. John

2006-01-01

Objective: This paper examines whether exposure to interparental violence in childhood predicts subsequent involvement in interpartner violence and violent crime after controlling for potentially confounding factors. Method: The investigation analyses data from the Christchurch Health and Development Study, a prospective, longitudinal study of a…

"Bounded" empowerment: analyzing tensions in the practice of youth-led participatory research in urban public schools.

PubMed

Ozer, Emily J; Newlan, Sami; Douglas, Laura; Hubbard, Elizabeth

2013-09-01

This multi-method study examines tensions in the practice of youth-led participatory research (YPAR) in urban high schools among 15 semester-cohorts. Student participants in the present study were 77 ethnically diverse youth from four high schools in a major metropolitan school district. Data were gathered using systematic classroom observations, interviews with teachers and students involved in the projects, and participant observation. The two most commonly-constrained phases of the YPAR project were issue selection and action steps. A central tension in the issue selection phase for projects enacted across multiple semester cohorts was the tension between original inquiry and "traction:" Sticking with the same topic enabled sustained building of strategic alliances and expertise for making change, but limited the incoming cohort's power to define the problem to be addressed. In further analyses, we identified processes that promoted student power despite continuity-related constraints-teachers' framing and buy-in strategies, "micro-power" compensation, and alignment of students' interests with the prior cohort-as well as constraints in other phases of the projects. This study's findings regarding the promotion of youth power in the face of constraints advance the integration of theory and practice in youth-led research and have implications for participatory research more broadly.

Cancer risk among patients with multiple sclerosis: A cohort study in Isfahan, Iran

PubMed Central

Etemadifar, Masoud; Jahanbani-Ardakani, Hamidreza; Ghaffari, Sara; Fereidan-Esfahani, Maboobeh; Changaei, Hossein; Aghadoost, Nazila; Jahanbani Ardakani, Ameneh; Moradkhani, Negin

2017-01-01

Background: Multiple sclerosis (MS), a central nervous system (CNS) autoimmune disorder, affects 2.3 million people around the world. Cancer kills around 7.5 million people annually. Both diseases have similar risks and intertwining molecular causes. Most studies focusing on MS and cancer have found an insignificant difference or reduction in the amount of cancer found in the MS community. Methods: We performed a cohort study using data from Isfahan Multiple Sclerosis Society (IMSS) and Isfahan cancer society and followed-up for 8 years on average (2006-2014). All of the 1718 MS patients were diagnosed according to McDonald’s criteria, then standardized incidence ratio and the numbers of expected cancer case were calculated. Results: While patients had an insignificant change in cancer prevalence, men had fewer cancer cases and women showed an increased prevalence of cancer. Certain types of cancer proved statistically significant. Breast cancer, nervous system cancers, and lymphoma were elevated in the cohort. Conclusion: Our results support the hypothesis that MS significantly affects certain cancers in a protective or associative manner. All cancer rates, except breast cancer, cancers located in the nervous system, and lymphomas were reduced in cohort, suggesting that unregulated immune function may provide protective effects to MS patients against cancer. PMID:28932368

Predictors of Low Back Pain Onset in a Prospective British Study

PubMed Central

Power, Chris; Frank, John; Hertzman, Clyde; Schierhout, Gill; Li, Leah

2001-01-01

Objectives. This study examined predictors of low back pain onset in a British birth cohort. Methods. Univariate and multivariate analyses focused on individuals who experienced onset of low back pain at 32 to 33 years of age (n= 571) and individuals who were pain free (n = 5210). Participants were members of the 1958 British birth cohort. Results. Incident pain was elevated among those with psychological distress at 23 years of age (adjusted odds ratio [OR] = 2.52, 95% confidence interval [CI] = 1.65, 3.86) and among persistent moderate or heavy smokers (adjusted OR = 1.63, 95% CI = 1.23, 2.17). Significant univariate associations involving other factors (e.g., social class, childhood emotional status, body mass index, job satisfaction) did not persist in multivariate analyses. Conclusions. This prospectively studied cohort provides evidence that psychological distress more than doubles later risk of low back pain, with smoking having a modest independent effect. Other prospective studies are needed to confirm these findings before implications for low back pain prevention can be assessed. PMID:11574334

The Jerusalem Perinatal Study cohort, 1964–2005: methods and a review of the main results

PubMed Central

Harlap, Susan; Davies, A. Michael; Deutsch, Lisa; Calderon-Margalit, Ronit; Manor, Orly; Paltiel, Ora; Tiram, Efrat; Yanetz, Rivka; Perrin, Mary C.; Terry, Mary B.; Malaspina, Dolores; Friedlander, Yechiel

2010-01-01

Summary The Jerusalem Perinatal Study recorded information on population-based cohorts of 92 408 live- and stillbirths in 1964–76, and their parents, with active surveillance of infant deaths and birth defects. Data on maternal conditions, obstetric complications and interventions during labour and delivery were recorded for 92% of the births. Subsets were surveyed with antenatal interviews in 1965–68 (n = 11 467), paediatric admissions to hospital (n = 17 782) and postpartum interviews in 1975–76 (n = 16 912). Data from some offspring were linked to records of a health examination at age 17. The offspring, mothers and fathers have been traced recently, their vital status assessed, and the data linked to Israel’s Cancer Registry and Psychiatric Registry. This paper describes the different types of data available, their sources, and some potential biases. Characteristics of this unique population are shown. Findings from the study are reviewed and a list of references is provided. The cohorts provide a unique source of data for a wide variety of studies. PMID:17439536

The performance of immigrants in the Norwegian labor market.

PubMed

Hayfron, J E

1998-01-01

"This paper tests the assimilation hypothesis with Norwegian data. Using both cross-section and cohort analyses, the results show that the 1970-1979 immigrant cohort experienced an earnings growth of about 11% between 1980 and 1990, when their earnings profile was compared to that of natives. This is lower than the 19% assimilation rate predicted by the cross-section method. On the contrary, the results reveal a rapid earnings divergence across cohorts, and between the 1960-1969 cohort and natives." excerpt

Trends in socioeconomic inequalities in anthropometric status in a population undergoing the nutritional transition: data from 1982, 1993 and 2004 pelotas birth cohort studies

PubMed Central

2012-01-01

Background Socioeconomic inequalities in child nutrition may change rapidly over time, particularly in populations undergoing the nutrition transition. Yet, the few available studies are repeated cross-sectional surveys. By studying three prospective birth cohorts in the same city over a period of more than two decades, we describe secular trends in overweight and stunting at different ages, according to socioeconomic position. Methods Population-based birth cohort studies were launched in the city of Pelotas (Brazil) in 1982, 1993 and 2004, with follow-up visits at twelve, 24 and 48 months. Children were weighed and measured at every visit. Z-scores of length/height-for-age and body mass index-for-age were calculated using the WHO Child Growth Standards. The slope and relative indices of inequality, based on family income quintiles, were estimated for each follow-up visit. Results Between the 1982 and 2004 cohorts, stunting among four-year-olds declined (from 10.9% to 3.6%), while overweight increased (from 7.6% to 12.3%). In every visit, stunting prevalence was inversely related to income. Both absolute and relative inequalities declined over time; among four-year-olds stunting dropped from 26.0% in the 1982 cohort to 6.7% in the 2004 cohort in the poorest group, while in the richest group stunting prevalence dropped from 2.7% in 1982 to 1.1% in the 2004 cohort study. The secular trend towards increased overweight was evident for four-year-olds, in almost all socioeconomic groups, but not among one and two-year-olds. Among four-year old children, overweight prevalence increased in all income quintiles, by 130% in the middle-income group, 64% in the poorest and 41% in the richest group. Conclusions The decline in stunting is remarkable, but the increase in overweight among four-year olds – particularly among the poorest and the middle-income groups– requires concerted efforts to prevent the long term consequences of child overweight. PMID:22776157

Non-thyroid cancer incidence in Belarusian residents exposed to Chernobyl fallout in childhood and adolescence: Standardized Incidence Ratio analysis, 1997–2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostroumova, Evgenia, E-mail: ostroumovae@iarc.fr; Hatch, Maureen, E-mail: hatchm@mail.nih.gov; Brenner, Alina, E-mail: brennera@mail.nih.gov

Background: While an increased risk of thyroid cancer from post-Chernobyl exposure to Iodine-131 (I-131) in children and adolescents has been well-documented, risks of other cancers or leukemia as a result of residence in radioactively contaminated areas remain uncertain. Methods: We studied non-thyroid cancer incidence in a cohort of about 12,000 individuals from Belarus exposed under age of 18 years to Chernobyl fallout (median age at the time of Chernobyl accident of 7.9 years). During 15 years of follow-up from1997 through 2011, 54 incident cancers excluding thyroid were identified in the study cohort with 142,968 person-years at risk. We performed Standardizedmore » Incidence Ratio (SIR) analysis of all solid cancers excluding thyroid (n=42), of leukemia (n=6) and of lymphoma (n=6). Results: We found no significant increase in the incidence of non-thyroid solid cancer (SIR=0.83, 95% Confidence Interval [CI]: 0.61; 1.11), lymphoma (SIR=0.66, 95% CI: 0.26; 1.33) or leukemia (SIR=1.78, 95% CI: 0.71; 3.61) in the study cohort as compared with the sex-, age- and calendar-time-specific national rates. These findings may in part reflect the relatively young age of study subjects (median attained age of 33.4 years), and long latency for some radiation-related solid cancers. Conclusions: We found no evidence of statistically significant increases in solid cancer, lymphoma and leukemia incidence 25 years after childhood exposure in the study cohort; however, it is important to continue follow-up non-thyroid cancers in individuals exposed to low-level radiation at radiosensitive ages. - Highlights: • We monitor cancers in a Belarusian cohort of exposed as children due to Chernobyl. • No increase in solid cancer rates was found as compared to the national rates. • An elevation of leukemia rates was detected, although statistically insignificant. • Results are consistent with those in a cohort of exposed as children in Ukraine. • Further monitoring of cancer situation in this cohort is warranted.« less

Revisiting the “Golden Hour”: An Evaluation of Out-of-Hospital Time in Shock and Traumatic Brain Injury

PubMed Central

Newgard, Craig D.; Meier, Eric N.; Bulger, Eileen M.; Buick, Jason; Sheehan, Kellie; Lin, Steve; Minei, Joseph P.; Barnes-Mackey, Roxy A.; Brasel, Karen

2015-01-01

Study Objective We evaluated shock and traumatic brain injury (TBI) patients previously enrolled in an out-of-hospital clinical trial to test the association between out-of-hospital time and outcome. Methods This was a secondary analysis of shock and TBI patients ≥ 15 years enrolled in a Resuscitation Outcomes Consortium out-of-hospital clinical trial by 81 EMS agencies transporting to 46 Level I and II trauma centers in 11 sites (May 2006 through May 2009). Inclusion criteria were: SBP ≤ 70 mmHg or SBP 71 - 90 mmHg with heart rate ≥ 108 beats per minute (shock cohort) and Glasgow Coma Scale score ≤ 8 (TBI cohort); patients meeting both criteria were placed in the shock cohort. Primary outcomes were 28-day mortality (shock cohort) and 6-month Glasgow Outcome Scale - Extended (GOSE) ≤ 4 (TBI cohort). Results There were 778 patients in the shock cohort (26% 28-day mortality) and 1,239 patients in the TBI cohort (53% 6-month GOSE ≤ 4). Out-of-hospital time > 60 minutes was not associated with worse outcomes after accounting for important confounders in the shock cohort (adjusted odds ratio [aOR] 1.42, 95% CI 0.77-2.62) or TBI cohort (aOR 0.80, 95% CI 0.52-1.21). However, shock patients requiring early critical hospital resources and arriving > 60 minutes had higher 28-day mortality (aOR 2.37, 95% CI 1.05-5.37); this finding was not observed among a similar TBI subgroup. Conclusions Among out-of-hospital trauma patients meeting physiologic criteria for shock and TBI, there was no association between time and outcome. However, the subgroup of shock patients requiring early critical resources arriving after 60 minutes had higher mortality. PMID:25596960

Tiered protocol implementation improves treatment of hypoglycaemia in a neurosciences critical care and surgical intensive care unit.

PubMed

Van Berkel, Megan A; MacDermott, Jennifer; Dungan, Kathleen M; Cook, Charles H; Murphy, Claire V

2017-12-01

Although studies demonstrate techniques to limit hypoglycaemia in critically ill patients, there are limited data supporting methods to improve management of existing hypoglycaemia. Assess the impact and sustainability of a computerised, three tiered, nurse driven protocol for hypoglycaemia treatment. Retrospective pre and post protocol study. Neurosciences and surgical intensive care units at a tertiary academic medical centre. Patients with a hypoglycaemic episode were included during a pre-protocol or post-protocol implementation period. An additional six-month cohort was evaluated to assess sustainability. Fifty-four patients were included for evaluation (35 pre- and 19 post-protocol); 122 patients were included in the sustainability cohort. Hypoglycaemia treatment significantly improved in the post-protocol cohort (20% vs. 52.6%, p=0.014); with additional improvement to 79.5% in the sustainability cohort. Time to follow-up blood glucose was decreased after treatment from 122 [Q1-Q3: 46-242] minutes pre-protocol to 25 [Q1-Q3: 9-48] minutes post protocol (p<0.0001). This reduction was maintained in the sustainability cohort [median of 29min (Q1-Q3: 20-51)]. Implementation of a nurse-driven, three-tiered protocol for treatment of hypoglyacemia significantly improved treatment rates, as well as reduced time to recheck blood glucose measurement. These benefits were sustained during a six-month period after protocol implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

A comparison of mental health outcomes in persons entering U.S. military service before and after September 11, 2001.

PubMed

Wells, Timothy S; Ryan, Margaret A K; Jones, Kelly A; Hooper, Tomoko I; Boyko, Edward J; Jacobson, Isabel G; Smith, Tyler C; Gackstetter, Gary D

2012-02-01

It has been hypothesized that those who entered military service in the pre-September 11, 2001 era might have expectations incongruent with their subsequent experiences, increasing the risk for posttraumatic stress disorder (PTSD) or other mental disorders. A subset of Millennium Cohort Study participants who joined the military during 1995-1999 was selected and compared with a subset of members who joined the military in 2002 or later. Outcomes included new-onset symptoms of PTSD, depression, panic/anxiety, and alcohol-related problems. Multivariable methods adjusted for differences in demographic and military characteristics. More than 11,000 cohort members were included in the analyses. Those who entered service in the pre-September 11 era had lower odds of new-onset PTSD symptoms (odds ratio [OR] 0.74, 95% CI [0.59, 0.93]) compared with the post-September 11 cohort. There were no statistically significant differences in rates of new-onset symptoms of depression, panic/anxiety, or alcohol-related problems between the groups. The cohort who entered military service in the pre-September 11 era did not experience higher rates of new-onset mental health challenges compared with the cohort who entered service after September 11, 2001. Findings support the concept that the experience of war, and resulting psychological morbidity, is not a function of incongruent expectations. Copyright © 2012 International Society for Traumatic Stress Studies.

Stability of conditioned pain modulation in two musculoskeletal pain models: investigating the influence of shoulder pain intensity and gender

PubMed Central

2013-01-01

Background Several chronic pain populations have demonstrated decreased conditioned pain modulation (CPM). However there is still a need to investigate the stability of CPM paradigms before the measure can be recommended for implementation. The purpose of the present study was to assess whether shoulder pain intensity and gender influence CPM stability within and between sessions. Methods This study examined two different musculoskeletal pain models, clinical shoulder pain and an experimental model of shoulder pain induced with eccentric exercise in healthy participants. Patients in the clinical cohort (N = 134) were tested before surgery and reassessed 3 months post-surgery. The healthy cohort (N = 190) was examined before inducing pain at the shoulder, and 48 and 96 hours later. Results Our results provide evidence that 1) stability of inhibition is not related to changes in pain intensity, and 2) there are sex differences for CPM stability within and between days. Conclusions Fluctuation of pain intensity did not significantly influence CPM stability. Overall, the more stable situations for CPM were females from the clinical cohort and males from the healthy cohort. PMID:23758907

Development and validation of electronic surveillance tool for acute kidney injury: A retrospective analysis.

PubMed

Ahmed, Adil; Vairavan, Srinivasan; Akhoundi, Abbasali; Wilson, Gregory; Chiofolo, Caitlyn; Chbat, Nicolas; Cartin-Ceba, Rodrigo; Li, Guangxi; Kashani, Kianoush

2015-10-01

Timely detection of acute kidney injury (AKI) facilitates prevention of its progress and potentially therapeutic interventions. The study objective is to develop and validate an electronic surveillance tool (AKI sniffer) to detect AKI in 2 independent retrospective cohorts of intensive care unit (ICU) patients. The primary aim is to compare the sensitivity, specificity, and positive and negative predictive values of AKI sniffer performance against a reference standard. This study is conducted in the ICUs of a tertiary care center. The derivation cohort study subjects were Olmsted County, MN, residents admitted to all Mayo Clinic ICUs from July 1, 2010, through December 31, 2010, and the validation cohort study subjects were all patients admitted to a Mayo Clinic, Rochester, campus medical/surgical ICU on January 12, 2010, through March 23, 2010. All included records were reviewed by 2 independent investigators who adjudicated AKI using the Acute Kidney Injury Network criteria; disagreements were resolved by a third reviewer. This constituted the reference standard. An electronic algorithm was developed; its precision and reliability were assessed in comparison with the reference standard in 2 separate cohorts, derivation and validation. Of 1466 screened patients, a total of 944 patients were included in the study: 482 for derivation and 462 for validation. Compared with the reference standard in the validation cohort, the sensitivity and specificity of the AKI sniffer were 88% and 96%, respectively. The Cohen κ (95% confidence interval) agreement between the electronic and the reference standard was 0.84 (0.78-0.89) and 0.85 (0.80-0.90) in the derivation and validation cohorts. Acute kidney injury can reliably and accurately be detected electronically in ICU patients. The presented method is applicable for both clinical (decision support) and research (enrollment for clinical trials) settings. Prospective validation is required. Copyright © 2015 Elsevier Inc. All rights reserved.

Patient-Level DNA Damage and Repair Pathway Profiles and Prognosis After Prostatectomy for High-Risk Prostate Cancer.

PubMed

Evans, Joseph R; Zhao, Shuang G; Chang, S Laura; Tomlins, Scott A; Erho, Nicholas; Sboner, Andrea; Schiewer, Matthew J; Spratt, Daniel E; Kothari, Vishal; Klein, Eric A; Den, Robert B; Dicker, Adam P; Karnes, R Jeffrey; Yu, Xiaochun; Nguyen, Paul L; Rubin, Mark A; de Bono, Johann; Knudsen, Karen E; Davicioni, Elai; Feng, Felix Y

2016-04-01

A substantial number of patients diagnosed with high-risk prostate cancer are at risk for metastatic progression after primary treatment. Better biomarkers are needed to identify patients at the highest risk to guide therapy intensification. To create a DNA damage and repair (DDR) pathway profiling method for use as a prognostic signature biomarker in high-risk prostate cancer. A cohort of 1090 patients with high-risk prostate cancer who underwent prostatectomy and were treated at 3 different academic institutions were divided into a training cohort (n = 545) and 3 pooled validation cohorts (n = 232, 130, and 183) assembled for case-control or case-cohort studies. Profiling of 9 DDR pathways using 17 gene sets for GSEA (Gene Set Enrichment Analysis) of high-density microarray gene expression data from formalin-fixed paraffin-embedded prostatectomy samples with median 10.3 years follow-up was performed. Prognostic signature development from DDR pathway profiles was studied, and DDR pathway gene mutation in published cohorts was analyzed. Biochemical recurrence-free, metastasis-free, and overall survival. Across the training cohort and pooled validation cohorts, 1090 men were studied; mean (SD) age at diagnosis was 65.3 (6.4) years. We found that there are distinct clusters of DDR pathways within the cohort, and DDR pathway enrichment is only weakly correlated with clinical variables such as age (Spearman ρ [ρ], range, -0.07 to 0.24), Gleason score (ρ, range, 0.03 to 0.20), prostate-specific antigen level (ρ, range, -0.07 to 0.10), while 13 of 17 DDR gene sets are strongly correlated with androgen receptor pathway enrichment (ρ, range, 0.33 to 0.82). In published cohorts, DDR pathway genes are rarely mutated. A DDR pathway profile prognostic signature built in the training cohort was significantly associated with biochemical recurrence-free, metastasis-free, and overall survival in the pooled validation cohorts independent of standard clinicopathological variables. The prognostic performance of the signature for metastasis-free survival appears to be stronger in the younger patients (HR, 1.67; 95% CI, 1.12-2.50) than in the older patients (HR, 0.77; 95% CI, 0.29-2.07) on multivariate Cox analysis. DNA damage and repair pathway profiling revealed patient-level variations and the DDR pathways are rarely affected by mutation. A DDR pathway signature showed strong prognostic performance with the long-term outcomes of metastasis-free and overall survival that may be useful for risk stratification of high-risk prostate cancer patients.

[A retrospective cohort study on mortality among silicotic workers in Hong Kong with emphasis on lung cancer].

PubMed

Yu, Ignatius Ts; Tse, Lap Ah; Chi, Chiu-leung; Tze, Wai-wong; Cheuk, Ming-Tam; Alan, Ck-chan

2008-01-01

To investigate the relationship between silica or silicosis and lung cancer in a large cohort of silicotic workers in Hong Kong. All workers with silicosis in Hong Kong diagnosed between 1981 and 1998 were followed up till the end of 1999 to ascertain their vital status and causes of death, using the corresponding mortality rates of Hong Kong males of the same period as external comparison. Standardized mortality ratios (SMR) for lung cancer and other major causes of death were calculated. Person-year method was used. Axelson's indirect method was performed to adjust for the confounding effect of smoking. Penalized smoothing spline (p-spline) models were used to evaluate the exposure-response relationship between silica dust exposure and lung cancer mortality. A total of 2789 newly diagnosed cases of silicosis were included in the cohort, with an overall 24 992.6 person-years of observations. The loss-to-follow-up rate was only 2.9%. Surface construction workers (51%) and underground caisson workers (37%) constituted the major part of the cohort. There were 853 silicotics observed with an average age at death of 63.8 years. The SMR for all causes and all cancers increased significantly. The leading cause of death was non-malignant respiratory diseases. About 86 deaths were from lung cancer, giving a SMR of 1.69 (95% CI: 1.35 approximately 2.09). The risk of lung cancer death among workers in surface construction, underground caisson, and entire cohort was reduced to 1.12 (95% CI: 0.89 approximately 1.38), 1.09 (95% CI: 0.82 approximately 1.42) and 1.56 (95% CI: 0.98 approximately 2.36) respectively, after indirectly adjusting for smoking. from P-spline model did not show a clear exposure-response relationship between silica dust (CDE and MDC) and lung cancer mortality. This cohort study did not show an increased risk of lung cancer mortality among silicotic workers. P-spline model does not support an exposure-response relationship between silica dust exposure and lung cancer mortality.

Does high sugar consumption exacerbate cardiometabolic risk factors and increase the risk of type 2 diabetes and cardiovascular disease?

PubMed Central

Sonestedt, Emily; Øverby, Nina Cecilie; Laaksonen, David E.; Birgisdottir, Bryndis Eva

2012-01-01

Consumption of sugar has been relatively high in the Nordic countries; the impact of sugar intake on metabolic risk factors and related diseases has been debated. The objectives were to assess the effect of sugar intake (sugar-sweetened beverages, sucrose and fructose) on association with type 2 diabetes, cardiovascular disease and related metabolic risk factors (impaired glucose tolerance, insulin sensitivity, dyslipidemia, blood pressure, uric acid, inflammation markers), and on all-cause mortality, through a systematic review of prospective cohort studies and randomised controlled intervention studies published between January 2000 and search dates. The methods adopted were as follows: the first search was run in PubMed in October 2010. A second search with uric acid as risk marker was run in April 2011. The total search strategy was rerun in April 2011 in SveMed+. An update was run in PubMed in January 2012. Two authors independently selected studies for inclusion from the 2,743 abstracts according to predefined eligibility criteria. The outcome was that out of the 17 studies extracted, 15 were prospective cohort studies and two were randomised controlled crossover trials. All of the studies included only adults. With respect to incident type 2 diabetes (nine studies), four of six prospective cohort studies found a significant positive association for sugar-sweetened beverage intake. In general, larger cohort studies with longer follow-up more often reported positive associations, and BMI seemed to mediate part of the increased risk. For other metabolic or cardiovascular risk factors or outcomes, too few studies have been published to draw conclusions. In conclusion, data from prospective cohort studies published in the years 2000–2011 suggest that sugar-sweetened beverages probably increase the risk of type 2 diabetes. For related metabolic risk factors, cardiovascular disease or all-cause mortality and other types of sugars, too few studies were available to draw conclusions. PMID:22855643

Beyond One Hundred: A Cohort Analysis of Italian Centenarians and Semi-supercentenarians.

PubMed

Caselli, Graziella; Battaglini, Marco; Capacci, Giorgia

2018-03-26

Although the increase in the number of centenarians is well documented today in countries with advanced demographic data, the same is not true for those aged 105 and over. The first aim of this paper, was to analyze the demographic characteristics of the 4,626 validated semi-super and 102 supercentenarians for the cohorts born between 1896 and 1910, referring to Italian Semi-Supercentenarians Survey (SSC). Then, starting from this data and from the survival  histories  in old ages - reconstructed by Vincent's Extinct - Cohort Method - for the cohorts born between 1870 and 1904, the most important aim was to analyze longevity history and the trend of gender gap of the Italian oldest cohorts beyond 100 years old.  The Italian centenarians and semi-supercentenarians increase from the first to the last cohort is due to the survival rise in old ages and the increase in the gender gap at extreme ages depends on the higher survival of women than men after 60 years old. Around 110-112 for both genders (for women in particular) a kind of resistance to further progress seems to appear in our analysis as in more recent studies on supercentenarians.

Meat intake and meat preparation in relation to risk of postmenopausal breast cancer in the NIH-AARP diet and health study.

PubMed

Kabat, Geoffrey C; Cross, Amanda J; Park, Yikyung; Schatzkin, Arthur; Hollenbeck, Albert R; Rohan, Thomas E; Sinha, Rashmi

2009-05-15

A number of studies have reported that intake of red meat or meat cooked at high temperatures is associated with increased risk of breast cancer, but other studies have shown no association. We assessed the association between meat, meat-cooking methods, and meat-mutagen intake and postmenopausal breast cancer in the NIH-AARP Diet and Health Study cohort of 120,755 postmenopausal women who completed a food frequency questionnaire at baseline (1995-1996) as well as a detailed meat-cooking module within 6 months following baseline. During 8 years of follow-up, 3,818 cases of invasive breast cancer were identified in this cohort. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). After adjusting for covariates, intake of total meat, red meat, meat cooked at high temperatures, and meat mutagens showed no association with breast cancer risk. This large prospective study with detailed information on meat preparation methods provides no support for a role of meat mutagens in the development of postmenopausal breast cancer. (c) 2008 Wiley-Liss, Inc.

How are European birth-cohort studies engaging and consulting with young cohort members?

PubMed

Lucas, Patricia J; Allnock, Debra; Jessiman, Tricia

2013-04-11

Birth cohort studies, where parents consent for their child to be enrolled in a longitudinal study prior to or soon after birth, are a powerful study design in epidemiology and developmental research. Participation often continues into adulthood. Where participants are enrolled as infants, provision should be made for consent, consultation and involvement in study design as they age. This study aims to audit and describe the extent and types of consultation and engagement currently used in birth cohorts in Europe. Seventy study groups (representing 84 cohorts) were contacted to ask about their practice in engaging and involving study members. Information was gathered from study websites and publications, 15 cohorts provided additional information via email and 17 cohorts were interviewed over the phone. The cohorts identified confirm the growth of this study design, with more than half beginning since 1990, and 4 since 2011. Most studies maintain a website open to the general public, although many are written for the scientific community only. Five studies have web pages specifically for young cohort members and one study provides a dedicated page for fathers. Cohorts send newsletters, cards, and summaries of findings to participants to stay in touch. Six cohorts use Facebook for this purpose. Five cohorts provide feedback opportunities for participants after completing a round of data collection. We know of just 8 cohorts who have a mechanism for consulting with parents and 3 a mechanism for consulting with young people themselves, although these were 'one off' consultations for some groups. Barriers to further consultation with cohort members were: concerns about impact on quality of research, ethical constraints, resource limitations, lack of importance, and previous adverse experiences. Although the children in some of the cohorts are still young (born in the last 10 years) many are old enough to include some element of consultation. Barriers to greater participation identified here have been overcome in some cohorts and in other fields. Within the scope of their funding and resources, birth cohort studies should consider ways in which they could increase engagement, consultation, and co-production with research participants.

Comparison of food and nutrient intakes between cohorts of the HAPIEE and Whitehall II studies

PubMed Central

Pajak, Andrzej; Malyutina, Sofia; Kubinova, Ruzena; Bobak, Martin; Brunner, Eric J.

2016-01-01

Background: Differences in dietary habits have been suggested as an important reason for the large health gap between Eastern and Western European populations. Few studies have compared individual-level nutritional data directly between the two regions. This study addresses this hypothesis by comparing food, drink and nutrient intakes in four large population samples. Methods: Czech, Polish and Russian participants of the Health, Alcohol and Psychosocial Factors in Eastern Europe (HAPIEE) study, and British participants in the Whitehall II study, altogether 29 972 individuals aged 45–73 years, were surveyed in 2002–2005. Dietary data were collected by customised food frequency questionnaires. Reported food, drink and nutrient intake data were harmonised and compared between cohorts using multivariable adjusted quantile regression models. Results: Median fruit and vegetable intakes were lower in the pooled Eastern European sample, but not in all country cohorts, compared with British subjects. Median daily consumption of fruits were 275, 213, 130 and 256 g in the Czech, Polish, Russian and Whitehall II cohort, respectively. The respective median daily intakes of vegetables were 185, 197, 292 and 246 g. Median intakes of animal fat foods and saturated fat, total fat and cholesterol nutrients were significantly higher in the Czech, Polish and Russian cohorts compared with the British; for example, median daily intakes of saturated fatty acids were 31.3, 32.5, 29.2 and 25.4 g, respectively. Conclusion: Our findings suggest that there are important differences in dietary habits between and within Eastern and Western European populations which may have contributed to the health gap between the two regions. PMID:26637342

A comparison of propensity score-based approaches to health service evaluation: a case study of a preoperative physician-led clinic for high-risk surgical patients.

PubMed

Pham, Clarabelle T; Gibb, Catherine L; Mittinty, Murthy N; Fitridge, Robert A; Marshall, Villis R; Karnon, Jonathan D

2016-10-01

A physician-led clinic for the preoperative optimization and management of high-risk surgical patients was implemented in a South Australian public hospital in 2008. This study aimed to estimate the costs and effects of the clinic using a mixed retrospective and prospective observational study design. Alternative propensity score estimation methods were applied to retrospective routinely collected administrative and clinical data, using weighted and matched cohorts. Supplementary survey-based prospective data were collected to inform the analysis of the retrospective data and reduce potential unmeasured confounding. Using weighted cohorts, clinic patients had a significantly longer mean length of stay and higher mean cost. With the matched cohorts, reducing the calliper width resulted in a shorter mean length of stay in the clinic group, but the costs remained significantly higher. The prospective data indicated potential unmeasured confounding in all analyses other than in the most tightly matched cohorts. The application of alternative propensity-based approaches to a large sample of retrospective data, supplemented with a smaller sample of prospective data, informed a pragmatic approach to reducing potential observed and unmeasured confounding in an evaluation of a physician-led preoperative clinic. The need to generate tightly matched cohorts to reduce the potential for unmeasured confounding indicates that significant uncertainty remains around the effects of the clinic. This study illustrates the value of mixed retrospective and prospective observational study designs but also underlines the need to prospectively plan for the evaluation of costs and effects alongside the implementation of significant service innovations. © 2016 John Wiley & Sons, Ltd.

The Mother-Infant Study Cohort (MISC): Methodology, challenges, and baseline characteristics

PubMed Central

Hashim, Mona; Shaker Obaid, Reyad; Hasan, Hayder; Naja, Farah; Al Ghazal, Hessa; Jan Jan Mohamed, Hamid; Al Hilali, Marwa; Rayess, Rana; Izzaldin, Ghamra

2018-01-01

Background The United Arab Emirates (UAE) exhibits alarming high prevalence of Non-Communicable Diseases (NCDs) and their risk factors. Emerging evidence highlighted the role of maternal and early child nutrition in preventing later-onset NCDs. The objectives of this article are to describe the design and methodology of the first Mother and Infant Study Cohort (MISC) in UAE; present the baseline demographic characteristics of the study participants; and discuss the challenges of the cohort and their respective responding strategies. Methods The MISC is an ongoing two-year prospective cohort study which recruited Arab pregnant women in their third trimester from prenatal clinics in Dubai, Sharjah and Ajman. Participants will be interviewed six times (once during pregnancy, at delivery, and at 2, 6, 12 and 24months postpartum). Perinatal information is obtained from hospital records. Collected data include socio-demographic characteristics, lifestyle, dietary intake and anthropometry; infant feeding practices, cognitive development; along with maternal and infant blood profile and breast milk profile. Results The preliminary results reported that 256 completed baseline assessment (mean age: 30.5±6.0 years; 76.6% multiparous; about 60% were either overweight or obese before pregnancy). The prevalence of gestational diabetes was 19.2%. Upon delivery, 208 women-infant pairs were retained (mean gestational age: 38.5±1.5 weeks; 33.3% caesarean section delivery; 5.3% low birthweight; 5.7% macrosomic deliveries). Besides participant retention, the main encountered challenges pertained to cultural complexity, underestimation the necessary start-up time, staff, and costs, and biochemical data collection. Conclusions Despite numerous methodological, logistical and sociocultural challenges, satisfactory follow-up rates are recorded. Strategies addressing challenges are documented, providing information for planning and implementing future birth cohort studies locally and internationally. PMID:29851999

Childhood socioeconomic position and adult mental wellbeing: Evidence from four British birth cohort studies

PubMed Central

Bann, David; Hardy, Rebecca; Gale, Catharine; Goodman, Alissa; Crawford, Claire; Stafford, Mai

2017-01-01

Background There is much evidence showing that childhood socioeconomic position is associated with physical health in adulthood; however existing evidence on how early life disadvantage is associated with adult mental wellbeing is inconsistent. This paper investigated whether childhood socioeconomic position (SEP) is associated with adult mental wellbeing and to what extent any association is explained by adult SEP using harmonised data from four British birth cohort studies. Methods The sample comprised 20,717 participants with mental wellbeing data in the Hertfordshire Cohort Study (HCS), the MRC National Survey of Health and Development (NSHD), the National Child Development Study (NCDS), and the British Cohort Study (BCS70). Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) scores at age 73 (HCS), 60–64 (NSHD), 50 (NCDS), or 42 (BCS70) were used. Harmonised socioeconomic position (Registrar General’s Social Classification) was ascertained in childhood (age 10/11) and adulthood (age 42/43). Associations between childhood SEP, adult SEP, and wellbeing were tested using linear regression and multi-group structural equation models. Results More advantaged father’s social class was associated with better adult mental wellbeing in the BCS70 and the NCDS. This association was independent of adult SEP in the BCS70 but fully mediated by adult SEP in the NCDS. There was no evidence of an association between father’s social class and adult mental wellbeing in the HCS or the NSHD. Conclusions Socioeconomic conditions in childhood are directly and indirectly, through adult socioeconomic pathways, associated with adult mental wellbeing, but findings from these harmonised data suggest this association may depend on cohort or age. PMID:29069091

A class of non-linear exposure-response models suitable for health impact assessment applicable to large cohort studies of ambient air pollution.

PubMed

Nasari, Masoud M; Szyszkowicz, Mieczysław; Chen, Hong; Crouse, Daniel; Turner, Michelle C; Jerrett, Michael; Pope, C Arden; Hubbell, Bryan; Fann, Neal; Cohen, Aaron; Gapstur, Susan M; Diver, W Ryan; Stieb, David; Forouzanfar, Mohammad H; Kim, Sun-Young; Olives, Casey; Krewski, Daniel; Burnett, Richard T

2016-01-01

The effectiveness of regulatory actions designed to improve air quality is often assessed by predicting changes in public health resulting from their implementation. Risk of premature mortality from long-term exposure to ambient air pollution is the single most important contributor to such assessments and is estimated from observational studies generally assuming a log-linear, no-threshold association between ambient concentrations and death. There has been only limited assessment of this assumption in part because of a lack of methods to estimate the shape of the exposure-response function in very large study populations. In this paper, we propose a new class of variable coefficient risk functions capable of capturing a variety of potentially non-linear associations which are suitable for health impact assessment. We construct the class by defining transformations of concentration as the product of either a linear or log-linear function of concentration multiplied by a logistic weighting function. These risk functions can be estimated using hazard regression survival models with currently available computer software and can accommodate large population-based cohorts which are increasingly being used for this purpose. We illustrate our modeling approach with two large cohort studies of long-term concentrations of ambient air pollution and mortality: the American Cancer Society Cancer Prevention Study II (CPS II) cohort and the Canadian Census Health and Environment Cohort (CanCHEC). We then estimate the number of deaths attributable to changes in fine particulate matter concentrations over the 2000 to 2010 time period in both Canada and the USA using both linear and non-linear hazard function models.

Different Pearl Indices in studies of hormonal contraceptives in the United States: Impact of study population

PubMed Central

Gerlinger, Christoph; Trussell, James; Mellinger, Uwe; Merz, Martin; Marr, Joachim; Bannemerschult, Ralf; Schellschmidt, Ilka; Endrikat, Jan

2014-01-01

Objective To examine the impact of subject characteristics on efficacy as measured by the Pearl Index (PI) in clinical trials and to make study populations similar by matching. Methods Our analysis used US data from four large Phase III studies. We compared results from one fertility control patch study with pooled data from three studies with virtually identical design on oral hormonal contraceptives. First, we identified three characteristics that had the most impact on the PI. Second, we used these three variables and matched subjects from the patch study with those from the OC studies. Finally, we calculated the PIs for matched and unmatched subjects from both the patch study and the OC studies. Results A total of 3,706 subjects were included in our analysis. The variables ‘Hispanic ethnicity’, ‘previous pregnancy’ and ‘previous use of hormonal contraceptives’ had the most impact on the PI. The PIs for the matched patch cohort and the matched OC cohort were 2.97 and 2.48, respectively. Those for the unmatched patch cohort and the unmatched OC cohort were 10.17 and 0.90, respectively. Conclusion Subject characteristics strongly influence the PI in clinical studies of hormonal contraceptives. In particular, Hispanic ethnicity, previous pregnancies and no previous use of hormonal contraceptives result in a higher PI. Implications PIs from different clinical trials cannot be meaningfully compared unless subject characteristics that have most impact on the PI are similar, or are made to be similar statistically as we did here by matching. PMID:24813941

Comparing the cohort design and the nested case–control design in the presence of both time-invariant and time-dependent treatment and competing risks: bias and precision

PubMed Central

Austin, Peter C; Anderson, Geoffrey M; Cigsar, Candemir; Gruneir, Andrea

2012-01-01

Purpose Observational studies using electronic administrative healthcare databases are often used to estimate the effects of treatments and exposures. Traditionally, a cohort design has been used to estimate these effects, but increasingly, studies are using a nested case–control (NCC) design. The relative statistical efficiency of these two designs has not been examined in detail. Methods We used Monte Carlo simulations to compare these two designs in terms of the bias and precision of effect estimates. We examined three different settings: (A) treatment occurred at baseline, and there was a single outcome of interest; (B) treatment was time varying, and there was a single outcome; and C treatment occurred at baseline, and there was a secondary event that competed with the primary event of interest. Comparisons were made of percentage bias, length of 95% confidence interval, and mean squared error (MSE) as a combined measure of bias and precision. Results In Setting A, bias was similar between designs, but the cohort design was more precise and had a lower MSE in all scenarios. In Settings B and C, the cohort design was more precise and had a lower MSE in all scenarios. In both Settings B and C, the NCC design tended to result in estimates with greater bias compared with the cohort design. Conclusions We conclude that in a range of settings and scenarios, the cohort design is superior in terms of precision and MSE. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22653805

Age-period-cohort analysis of the suicide rate in Korea.

PubMed

Park, Chiho; Jee, Yon Ho; Jung, Keum Ji

2016-04-01

The suicide rate has been increasing in Korea, and the country now has the highest rank in the world. This study aimed to present the long-term trends in Korea's suicide rate using Joinpoint analysis and age-period-cohort (APC) modeling. The population and the number of suicides for each five-year age group were obtained from the National Statistical Office for the period 1984-2013 for Koreans aged 10 years and older. We determined the changes in the trends in age-standardized mortality rates using Joinpoint. APC modeling was performed to describe the trends in the suicide rate using the intrinsic estimator method. The age-standardized suicide rate in men rapidly increased from 1989 to 2004, and slightly increased thereafter, whereas the suicide rate in women increased from 1989 to 2009 and then decreased thereafter. Within the same period, the suicide rate was higher among the older age groups than in the younger groups. Within the same birth cohort, the suicide rate of the older groups was also higher than that in the younger groups. Within the same age group, the suicide rate of the younger cohorts was higher than it was in the older cohorts. In the APC modeling, old age, recent period, and having been born before 1924 were associated with higher suicide rates. The accuracy and completeness of the suicide rate data may lead to bias. This study showed an increasing trend in the suicide rates for men and women after 1989. These trends may be mainly attributed to cohort effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Association between sexually transmitted disease and church membership. A retrospective cohort study of two Danish religious minorities

PubMed Central

Kørup, Alex Kappel; Thygesen, Lau Caspar; Christensen, René dePont; Johansen, Christoffer; Søndergaard, Jens; Hvidt, Niels Christian

2016-01-01

Objectives Studies comprising Danish Seventh-day Adventists (SDAs) and Danish Baptists found that members have a lower risk of chronic diseases including cancer. Explanations have pointed to differences in lifestyle, but detailed aetiology has only been sparsely examined. Our objective was to investigate the incidence of sexually transmitted diseases (STDs) among Danish SDAs and Baptists as a proxy for cancers related to sexual behaviour. Methods We followed the Danish Cohort of Religious Societies from 1977 to 2009, and linked it with national registers of all inpatient and outpatient care contacts using the National Patient Register. We compared the incidence of syphilis, gonorrhoea and chlamydia among members of the cohort with the general population. Results The cohort comprised 3119 SDA females, 1856 SDA males, 2056 Baptist females and 1467 Baptist males. For the entire cohort, we expected a total of 32.4 events of STD, and observed only 9. Female SDAs and Baptists aged 20–39 years had significant lower incidence of chlamydia (both p<0.001). Male SDAs and Baptists aged 20–39 years also had significant lower incidence of chlamydia (p<0.01 and p<0.05, respectively). No SDA members were diagnosed with gonorrhoea, when 3.4 events were expected, which, according to Hanley's ‘rule of three’, is a significant difference. No SDA or Baptist was diagnosed with syphilis. Conclusions The cohort shows significant lower incidence of STD, most likely including human papillomavirus, which may partly explain the lower incidence of cancers of the cervix, rectum, anus, head and neck. PMID:27016243

Special Education--Non-Special Education Achievement Gap in Math: Effects of Reporting Methods, Analytical Techniques, and Reclassification

ERIC Educational Resources Information Center

Thurlow, Martha L.; Wu, Yi-Chen; Lazarus, Sheryl S.; Ysseldyke, James E.

2016-01-01

Federal regulations indicate that the achievement gap must be closed between subgroups, including the gap between special education and non-special education students. We explored the ways in which achievement trends are influenced by three methods of reporting (cross-sectional, cohort-static, and cohort-dynamic). We also investigated (a) the ways…

Legal Teaching Methods to Diverse Student Cohorts: A Comparison between the United Kingdom, the United States, Australia and New Zealand

ERIC Educational Resources Information Center

Kraal, Diane

2017-01-01

This article makes a comparison across the unique educational settings of law and business schools in the United Kingdom, the United States, Australia and New Zealand to highlight differences in teaching methods necessary for culturally and ethnically mixed student cohorts derived from high migration, student mobility, higher education rankings…

"I Felt Like the Enemy and the Savior All at Once": English Teacher Identity in a Methods Course Wiki

ERIC Educational Resources Information Center

Jewett, Michelle Ann

2012-01-01

This study explores the identity constructions of two cohorts of preservice teachers enrolled in English methods courses during a semester of field experience. This research employs a qualitative methodology and documents the nature of participant's responses posted to online wiki forum. Data sources include archived electronic interactions…

Age-period-cohort analysis of hepatitis A incidence rates in Korea from 2002 to 2012

PubMed Central

2016-01-01

OBJECTIVES This study aimed to evaluate the epidemiology of hepatitis A in Korea from 2002 to 2012 using age-period-cohort analyses. METHODS We used claims data from the Korean National Health Insurance Corporation for the entire population. Census data from 2010 were used as the standard population. The incidence of hepatitis A was assumed to have a Poisson distribution, and the models and effects were evaluated using the intrinsic estimator method, the likelihood ratio, and the Akaike information criterion. RESULTS The incidence of hepatitis A gradually increased until 2007 (from 17.55 to 35.72 per 100,000 population) and peaked in 2009 (177.47 per 100,000 population). The highest incidence was observed among 27-29-year-old individuals when we omitted data from 2005 to 2007. From 2005 to 2007, the peak incidence was observed among 24-26-year-old individuals, followed by 27-29-year-olds. The best model fits were observed when the age-period-cohort variables were all considered at the same time for males, females, and the whole population. CONCLUSIONS The incidence of hepatitis A exhibited significant age-period-cohort effects; its incidence peaked in 2009 and was especially high among Koreans 20-39 years of age. These epidemiological patterns may help predict when high incidence rates of hepatitis A may occur in developing countries during their socioeconomic development. PMID:27703127

Cohort Profile: The Hawai’i Family Study of Cognition

PubMed Central

Onoye, Jane MM; Hishinuma, Earl S; McArdle, John J; Zonderman, Alan B; Takeshita, Junji

2014-01-01

Intergenerational longitudinal studies over the lifespan provide valuable information for understanding the contexts and dynamic relations among cognition, family and health in adults and the elderly. The Hawai‘i Family Study of Cognition (HFSC), initiated in the early 1970s, included a cohort of over 6500 individuals representing over 1800 families of parents and their offspring. The HFSC gathered data on cognitive, personality, biological and other psychosocial variables, and provided novel information on the nature of cognitive abilities, especially on family issues. Some families were reassessed with short-term retesting in the 1970s. A select sample of offspring and their siblings and spouses were re-measured in the 1980s. Decades later, a 40-year follow-up of the original HFSC cohort was facilitated by the availability of contemporary tracking and tracing methods and internet-based testing. A subgroup of the original HFSC participants was re-contacted and retested on contemporary cognitive as well as socio-demographic and health measures. In this paper, we describe the original HFSC cohort and the design and methodology of the re-contact and retest studies of the HFSC, plans for expanding the re-contact and retesting, as well as directions for future research and collaborations. The Principal Investigator may be contacted for more information regarding the application, review and approval process for data access requests from qualified individuals outside the project. PMID:24639439

All Our Babies Cohort Study: recruitment of a cohort to predict women at risk of preterm birth through the examination of gene expression profiles and the environment

PubMed Central

2010-01-01

Background Preterm birth is the leading cause of perinatal morbidity and mortality. Risk factors for preterm birth include a personal or familial history of preterm delivery, ethnicity and low socioeconomic status yet the ability to predict preterm delivery before the onset of preterm labour evades clinical practice. Evidence suggests that genetics may play a role in the multi-factorial pathophysiology of preterm birth. The All Our Babies Study is an on-going community based longitudinal cohort study that was designed to establish a cohort of women to investigate how a women's genetics and environment contribute to the pathophysiology of preterm birth. Specifically this study will examine the predictive potential of maternal leukocytes for predicting preterm birth in non-labouring women through the examination of gene expression profiles and gene-environment interactions. Methods/Design Collaborations have been established between clinical lab services, the provincial health service provider and researchers to create an interdisciplinary study design for the All Our Babies Study. A birth cohort of 2000 women has been established to address this research question. Women provide informed consent for blood sample collection, linkage to medical records and complete questionnaires related to prenatal health, service utilization, social support, emotional and physical health, demographics, and breast and infant feeding. Maternal blood samples are collected in PAXgene™ RNA tubes between 18-22 and 28-32 weeks gestation for transcriptomic analyses. Discussion The All Our Babies Study is an example of how investment in clinical-academic-community partnerships can improve research efficiency and accelerate the recruitment and data collection phases of a study. Establishing these partnerships during the study design phase and maintaining these relationships through the duration of the study provides the unique opportunity to investigate the multi-causal factors of preterm birth. The overall All Our Babies Study results can potentially lead to healthier pregnancies, mothers, infants and children. PMID:21192811

Lifecourse Socioeconomic Position and Racial Disparities in BMI Trajectories among Black and White Women: Exploring Cohort Effects in the Americans Changing Lives' Study

PubMed Central

Insaf, Tabassum Z; Shaw, Benjamin A; Yucel, Recai M; Chasan-Taber, Lisa; Strogatz, David S

2014-01-01

Introduction Few studies have analyzed the cohort effects of lifecourse socioeconomic position (SEP) on racial disparities in body mass index (BMI) trajectories. We assessed the contribution of lifecourse SEP on racial differences in BMI trajectories among two different age cohorts of women. Methods Four waves of the Americans' Changing Lives' study (1986–2002) were used to compute BMI trajectories for 2194 Black and White women. Multivariable associations of lifecourse SEP variables (father's education, perceived childhood family status, education, income, wealth and financial security) with Wave 1(W1) BMI and BMI change were assessed using mixed models. Results Black women had higher W1 BMI than White women in both cohorts (women <40 years in 1986 (+2.6 kg/m2 (95%CI: +1.71, +3.53)) and women>=40 in 1986 (+2.68 kg/m2 (95%CI:+2.12,3.24))); Black women in the younger cohort had a higher change in BMI (+0.73 kg/m2/year (95%CI:+0.17,+1.29)). High education was associated with lower W1 BMI in both cohorts (−1.34 (95%CI:−2.53,−0.15) and −1.08 kg/m2 (95%CI:−0.50,−1.65), respectively). Among the younger cohort, high income was associated with lower W1 BMI (−0.78kg/m2/unit log income (95%CI:−1.32,−0.25)) while among the older cohort, high father's education (−0.78 kg/m2 (95%CI:−0.06,−1.50)) and higher wealth (−0.26 kg/m2(95%CI:−0.43,−0.08))were associated with low W1 BMI. Racial disparities in W1 BMI were attenuated by 20–25% while those for BMI change remained unexplained on adjustment for lifecourse SEP. Conclusion In this large population-based dataset, results suggest that the contribution of lifecourse SEP to racial disparities in BMI may be established early in adulthood. PMID:25506543

Needle age and season influence photosynthetic temperature response and total annual carbon uptake in mature Picea mariana trees

PubMed Central

Jensen, Anna M.; Warren, Jeffrey M.; Hanson, Paul J.; Childs, Joanne; Wullschleger, Stan D.

2015-01-01

Background and Aims The carbon (C) balance of boreal terrestrial ecosystems is sensitive to increasing temperature, but the direction and thresholds of responses are uncertain. Annual C uptake in Picea and other evergreen boreal conifers is dependent on seasonal- and cohort-specific photosynthetic and respiratory temperature response functions, so this study examined the physiological significance of maintaining multiple foliar cohorts for Picea mariana trees within an ombrotrophic bog ecosystem in Minnesota, USA. Methods Measurements were taken on multiple cohorts of needles for photosynthetic capacity, foliar respiration (Rd) and leaf biochemistry and morphology of mature trees from April to October over 4 years. The results were applied to a simple model of canopy photosynthesis in order to simulate annual C uptake by cohort age under ambient and elevated temperature scenarios. Key Results Temperature responses of key photosynthetic parameters [i.e. light-saturated rate of CO2 assimilation (Asat), rate of Rubisco carboxylation (Vcmax) and electron transport rate (Jmax)] were dependent on season and generally less responsive in the developing current-year (Y0) needles compared with 1-year-old (Y1) or 2-year-old (Y2) foliage. Temperature optimums ranged from 18·7 to 23·7, 31·3 to 38·3 and 28·7 to 36·7 °C for Asat, Vcmax and Jmax, respectively. Foliar cohorts differed in their morphology and photosynthetic capacity, which resulted in 64 % of modelled annual stand C uptake from Y1&2 cohorts (LAI 0·67 m2 m−2) and just 36 % from Y0 cohorts (LAI 0·52 m2 m−2). Under warmer climate change scenarios, the contribution of Y0 cohorts was even less; e.g. 31 % of annual C uptake for a modelled 9 °C rise in mean summer temperatures. Results suggest that net annual C uptake by P. mariana could increase under elevated temperature, and become more dependent on older foliar cohorts. Conclusions Collectively, this study illustrates the physiological and ecological significance of different foliar cohorts, and indicates the need for seasonal- and cohort-specific model parameterization when estimating C uptake capacity of boreal forest ecosystems under ambient or future temperature scenarios. PMID:26220656

Autoimmune disease prevalence in a multiple sclerosis cohort in Argentina.

PubMed

Farez, Mauricio F; Balbuena Aguirre, María E; Varela, Francisco; Köhler, Alejandro A; Correale, Jorge

2014-01-01

Background. Comorbid autoimmune diseases in MS patients have been studied extensively with controversial results. Moreover, no such data exists for Latin-American MS patients. Methods. We conducted a case-control study aimed to establish the prevalence of autoimmune disorders in a cohort of Argentinean MS patients. Results. There were no significant differences in autoimmune disease prevalence in MS patients with respect to controls. The presence of one or more autoimmune disorders did not increase risk of MS (OR 0.85, 95% CI 0.6-1.3). Discussion. Our results indicate absence of increased comorbid autoimmune disease prevalence in MS patients, as well as of increased risk of MS in patients suffering from other autoimmune disorders.

Methods and feasibility of collecting occupational data for a large population-based cohort study in the United States: the reasons for geographic and racial differences in stroke study

PubMed Central

2014-01-01

Background Coronary heart disease and stroke are major contributors to preventable mortality. Evidence links work conditions to these diseases; however, occupational data are perceived to be difficult to collect for large population-based cohorts. We report methodological details and the feasibility of conducting an occupational ancillary study for a large U.S. prospective cohort being followed longitudinally for cardiovascular disease and stroke. Methods Current and historical occupational information were collected from active participants of the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study. A survey was designed to gather quality occupational data among this national cohort of black and white men and women aged 45 years and older (enrolled 2003–2007). Trained staff conducted Computer-Assisted Telephone Interviews (CATI). After a brief pilot period, interviewers received additional training in the collection of narrative industry and occupation data before administering the survey to remaining cohort members. Trained coders used a computer-assisted coding system to assign U.S. Census codes for industry and occupation. All data were double coded; discrepant codes were independently resolved. Results Over a 2-year period, 17,648 participants provided consent and completed the occupational survey (87% response rate). A total of 20,427 jobs were assigned Census codes. Inter-rater reliability was 80% for industry and 74% for occupation. Less than 0.5% of the industry and occupation data were uncodable, compared with 12% during the pilot period. Concordance between the current and longest-held jobs was moderately high. The median time to collect employment status plus narrative and descriptive job information by CATI was 1.6 to 2.3 minutes per job. Median time to assign Census codes was 1.3 minutes per rater. Conclusions The feasibility of conducting high-quality occupational data collection and coding for a large heterogeneous population-based sample was demonstrated. We found that training for interview staff was important in ensuring that narrative responses for industry and occupation were adequately specified for coding. Estimates of survey administration time and coding from digital records provide an objective basis for planning future studies. The social and environmental conditions of work are important understudied risk factors that can be feasibly integrated into large population-based health studies. PMID:24512119

Risk of Community-Acquired Pneumonia in Patients with a Diagnosis of Pernicious Anemia: A Population-Based Retrospective Cohort Study

PubMed Central

Almario, Christopher V.; Metz, David C.; Haynes, Kevin; Yang, Yu-Xiao

2015-01-01

Objective Pernicious anemia (PA) is an autoimmune disease that causes achlorhydria or profound hypochlorhydria. We conducted a population-based study to determine whether individuals with PA are at increased risk for community-acquired pneumonia (CAP). Methods We performed a retrospective cohort study using The Health Improvement Network (THIN) from the United Kingdom (1993 to 2009). The eligible study cohort included individuals 18 years of age or older and with at least 1 year of THIN follow-up. The exposed group consisted of individuals with a diagnosis code for PA. The unexposed group consisted of individuals without a diagnosis of PA and was frequency matched with the exposed group with respect to age, sex, and practice site. Cox regression analysis was used to determine the hazard ratio (HR) with 95% confidence interval (CI) for CAP associated with PA, accounting for a comprehensive list of potential confounders. Results The study included 13,605 individuals with PA and 50,586 non-PA subjects. The crude incidence rate of CAP was 9.4 per 1000 person-years for those with PA, versus 6.4 per 1000 person-years for those without PA. The multivariable adjusted HR for CAP associated with PA was 1.18, 95% CI 1.08 – 1.29. Conclusions In this large population-based cohort study, individuals with PA and presumed chronic achlorhydria were at increased risk for CAP. PMID:26225868

Electronic cigarettes as smoking cessation tool: are we there?

PubMed

Ghosh, Sohini; Drummond, M Bradley

2017-03-01

Electronic cigarette (e-cigarette) use is rapidly increasing, with many users reporting trying e-cigarettes as a method to quit combustible cigarettes. This review highlights recently published studies assessing the use of e-cigarettes as a tool for cessation of combustible cigarettes. When evaluating data from four randomized controlled trials and multiple cohort studies, differential association between e-cigarette use and cessation rates was seen. Cessation rates are highest in UK cohort studies and in studies using a multifaceted approach, such as with the addition of varenicline. The largest evidence base is derived from observational cohort studies. Overall, the current evidence remains too small for conclusive results regarding efficacy of e-cigarettes for combustible cessation. There does appear to be a consistent reduction in daily combustible cigarette use in regular e-cigarette users. Currently, there are conflicting data which can be used to support or dismiss e-cigarettes as a tool for smoking cessation. As larger population-based studies become available, the potential harms and benefits of e-cigarettes will become clearer. In the short term, shared decision-making with combustible cigarette users will be imperative when considering e-cigarettes as a smoking cessation tool.

Effects of Physical Activity on Cancer Survival: A Systematic Review

PubMed Central

Barbaric, Mary; Brooks, Eleanor; Moore, Lisa

2010-01-01

ABSTRACT Purpose: Physical activity (PA) has been suggested to help increase the survival of individuals with cancer. The objective of this review was to systematically evaluate and summarize the available evidence investigating the effect of PA on the survival of individuals with cancer. Methods: Electronic databases (CINAHL, EMBASE, and MEDLINE) were systematically searched for randomized controlled trials and cohort studies. Selected studies were assessed by two independent investigators for methodological quality, using the PEDro scale. Results: Ten prospective cohort studies met the inclusion criteria. Quality-assessment scores averaged 5/10 on the PEDro scale, with two articles obtaining a score of 6/10. The majority of studies found that individuals participating in higher levels of physical activity had a reduced risk of cancer-related mortality. This trend was observed specifically for breast, colon, and colorectal cancers. On average, it appears that engaging in higher levels of metabolic equivalent hours per week may help to improve survival rates among individuals diagnosed with cancer. Conclusion: Patients diagnosed with cancer demonstrated a trend toward increased survival with greater levels of PA. However, because only prospective cohort studies were included in the study, the conclusions drawn should be regarded with caution. PMID:21197176

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models.

PubMed

Hoffmann, Sabine; Laurier, Dominique; Rage, Estelle; Guihenneuc, Chantal; Ancelet, Sophie

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies.

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models

PubMed Central

Laurier, Dominique; Rage, Estelle

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies. PMID:29408862

Design, methods, and participant characteristics of the Impact of Personal Genomics (PGen) Study, a prospective cohort study of direct-to-consumer personal genomic testing customers.

PubMed

Carere, Deanna Alexis; Couper, Mick P; Crawford, Scott D; Kalia, Sarah S; Duggan, Jake R; Moreno, Tanya A; Mountain, Joanna L; Roberts, J Scott; Green, Robert C

2014-01-01

Designed in collaboration with 23andMe and Pathway Genomics, the Impact of Personal Genomics (PGen) Study serves as a model for academic-industry partnership and provides a longitudinal dataset for studying psychosocial, behavioral, and health outcomes related to direct-to-consumer personal genomic testing (PGT). Web-based surveys administered at three time points, and linked to individual-level PGT results, provide data on 1,464 PGT customers, of which 71% completed each follow-up survey and 64% completed all three surveys. The cohort includes 15.7% individuals of non-white ethnicity, and encompasses a range of income, education, and health levels. Over 90% of participants agreed to re-contact for future research.

Development of an Automated, Real Time Surveillance Tool for Predicting Readmissions at a Community Hospital

PubMed Central

Gildersleeve, R.; Cooper, P.

2013-01-01

Background The Centers for Medicare and Medicaid Services’ Readmissions Reduction Program adjusts payments to hospitals based on 30-day readmission rates for patients with acute myocardial infarction, heart failure, and pneumonia. This holds hospitals accountable for a complex phenomenon about which there is little evidence regarding effective interventions. Further study may benefit from a method for efficiently and inexpensively identifying patients at risk of readmission. Several models have been developed to assess this risk, many of which may not translate to a U.S. community hospital setting. Objective To develop a real-time, automated tool to stratify risk of 30-day readmission at a semirural community hospital. Methods A derivation cohort was created by extracting demographic and clinical variables from the data repository for adult discharges from calendar year 2010. Multivariate logistic regression identified variables that were significantly associated with 30-day hospital readmission. Those variables were incorporated into a formula to produce a Risk of Readmission Score (RRS). A validation cohort from 2011 assessed the predictive value of the RRS. A SQL stored procedure was created to calculate the RRS for any patient and publish its value, along with an estimate of readmission risk and other factors, to a secure intranet site. Results Eleven variables were significantly associated with readmission in the multivariate analysis of each cohort. The RRS had an area under the receiver operating characteristic curve (c-statistic) of 0.74 (95% CI 0.73-0.75) in the derivation cohort and 0.70 (95% CI 0.69-0.71) in the validation cohort. Conclusion Clinical and administrative data available in a typical community hospital database can be used to create a validated, predictive scoring system that automatically assigns a probability of 30-day readmission to hospitalized patients. This does not require manual data extraction or manipulation and uses commonly available systems. Additional study is needed to refine and confirm the findings. PMID:23874355

A comparison of Cox and logistic regression for use in genome-wide association studies of cohort and case-cohort design.

PubMed

Staley, James R; Jones, Edmund; Kaptoge, Stephen; Butterworth, Adam S; Sweeting, Michael J; Wood, Angela M; Howson, Joanna M M

2017-06-01

Logistic regression is often used instead of Cox regression to analyse genome-wide association studies (GWAS) of single-nucleotide polymorphisms (SNPs) and disease outcomes with cohort and case-cohort designs, as it is less computationally expensive. Although Cox and logistic regression models have been compared previously in cohort studies, this work does not completely cover the GWAS setting nor extend to the case-cohort study design. Here, we evaluated Cox and logistic regression applied to cohort and case-cohort genetic association studies using simulated data and genetic data from the EPIC-CVD study. In the cohort setting, there was a modest improvement in power to detect SNP-disease associations using Cox regression compared with logistic regression, which increased as the disease incidence increased. In contrast, logistic regression had more power than (Prentice weighted) Cox regression in the case-cohort setting. Logistic regression yielded inflated effect estimates (assuming the hazard ratio is the underlying measure of association) for both study designs, especially for SNPs with greater effect on disease. Given logistic regression is substantially more computationally efficient than Cox regression in both settings, we propose a two-step approach to GWAS in cohort and case-cohort studies. First to analyse all SNPs with logistic regression to identify associated variants below a pre-defined P-value threshold, and second to fit Cox regression (appropriately weighted in case-cohort studies) to those identified SNPs to ensure accurate estimation of association with disease.

Filipino women's diet and health study (FiLWHEL): design and methods

PubMed Central

Abris, Grace P.; Hong, Sangmo; Provido, Sherlyn Mae P.

2017-01-01

BACKGROUND Immigration to South Korea from neighboring Asian countries has risen dramatically, primarily due to marriage between Korean men and foreign women. Although Filipino women rank fourth among married immigrant women, little is known about the health condition of this population. This manuscript focuses on the design and methods of Filipino women's diet and health study (FiLWHEL). SUBJECTS/METHODS FiLWHEL is a cohort of Filipino women married to Korean men, aged 19 years old or over. The data collection comprised three parts: questionnaire, physical examination, and biospecimen collection. Questionnaires focused on demographic factors, diet, other health-related behaviors, acculturation and immigration-related factors, medical history, quality of life, and children's health information. Participants visited the recruitment site and answered the structured questionnaires through a face-to-face interview. We also measured their anthropometric features and collected fasting blood samples, toenails, and DNA samples. Recruitment started in 2014. RESULTS/CONCLUSIONS Collection of data is ongoing, and we plan to prospectively follow our cohort participants. We expect that our study, which is focused on married Filipino women immigrants, can elucidate nutritional/health status and the effects of transitional experiences from several lifestyle factors. PMID:28194268

Victimization among Peruvian Adolescents: Insights into Mental/Emotional Health from the Young Lives Study

ERIC Educational Resources Information Center

Lister, Cameron E.; Merrill, Ray M.; Vance, David L.; West, Joshua H.; Hall, Parley C.; Crookston, Benjamin T.

2015-01-01

Background: Bullying is a global problem among children and adolescents. The purpose of this study was to explore bully victimization in Peru and to identify potential adverse mental health and social outcomes resulting from bully victimization. Methods: This study analyzed data from an ongoing prospective cohort of children taking part in the…

The Effect of Foreign Language Study in Tennessee Middle Schools on Mathematics Achievement

ERIC Educational Resources Information Center

Tobias, Keith S.

2012-01-01

This quantitative method, quasi-experimental design study examined the possible effect of foreign language study in Tennessee middle schools on mathematics achievement. The population was 1,708 historical student test scores of a single cohort spanning 6th through 8th Grades from the same schools within a large urban public school district. NCLB…

Prenatal, Perinatal, and Neonatal Risk Factors for Specific Language Impairment: A Prospective Pregnancy Cohort Study

ERIC Educational Resources Information Center

Whitehouse, Andrew J. O.; Shelton, W. M. R.; Ing, Caleb; Newnham, John P.

2014-01-01

Purpose: Although genetic factors are known to play a causal role in specific language impairment (SLI), environmental factors may also be important. This study examined whether there are prenatal, perinatal, and neonatal factors that are associated with childhood SLI. Method: Participants were members of the Raine Study, a prospective cohort…

How Does Childhood Economic Disadvantage Lead to Crime?

ERIC Educational Resources Information Center

Fergusson, David; Swain-Campbell, Nicola; Horwood, John

2004-01-01

Background: This study sought to examine the associations between indices of socio-economic deprivation in childhood and later involvement in crime. Method: Data were gathered as part of the Christchurch Health and Development Study. In this project a cohort of 1,265 children born in Christchurch in 1977 have been studied from birth to age 21…

Late Language Emergence at 24 Months: An Epidemiological Study of Prevalence, Predictors, and Covariates

ERIC Educational Resources Information Center

Zubrick, Stephen R.; Taylor, Catherine L.; Rice, Mabel L.; Slegers, David W.

2007-01-01

Purpose: The primary objectives of this study were to determine the prevalence of late language emergence (LLE) and to investigate the predictive status of maternal, family, and child variables. Method: This is a prospective cohort study of 1,766 epidemiologically ascertained 24-month-old singleton children. The framework was an ecological model…

Age, cohort and period effects in the prevalence of sleep disturbances among older people: the impact of economic downturn.

PubMed

Dregan, Alex; Armstrong, David

2009-11-01

Using two longitudinal and nationally representative datasets, this study employs a cross-cohort analysis to examine age, cohort and period effects in the prevalence of sleep loss through worry for people over the age of 50 in the UK. The likelihood of reporting sleep loss through worry is calculated at two time-points for 7785 respondents from the Health and Activity Survey (HALs) and 21,834 respondents from the English Longitudinal Study of Ageing (ELSA), with baseline information on sleep loss through worry. Descriptive statistical methods were applied to determine the prevalence rates in sleep loss through worry at each survey within both datasets. The results of analysis reveal that sleep loss through worry declined with age, but this pattern was tempered by a temporary increase in the early 1990s. The contemporary economic downturn is suggested as a possible explanation for the significant increase in the prevalence of sleep loss through worry in 1991.

Associations between race, sex and immune response variations to rubella vaccination in two independent cohorts

PubMed Central

Haralambieva, Iana H.; Salk, Hannah M.; Lambert, Nathaniel D.; Ovsyannikova, Inna G.; Kennedy, Richard B.; Warner, Nathaniel D.; Pankratz, V.Shane; Poland, Gregory A.

2014-01-01

Introduction Immune response variations after vaccination are influenced by host genetic factors and demographic variables, such as race, ethnicity and sex. The latter have not been systematically studied in regard to live rubella vaccine, but are of interest for developing next generation vaccines for diverse populations, for predicting immune responses after vaccination, and for better understanding the variables that impact immune response. Methods We assessed associations between demographic variables, including race, ethnicity and sex, and rubella-specific neutralizing antibody levels and secreted cytokines (IFN! , IL-6) in two independent cohorts (1,994 subjects), using linear and linear mixed models approaches, and genetically defined racial and ethnic categorizations. Results Our replicated findings in two independent, large, racially diverse cohorts indicate that individuals of African descent have significantly higher rubella-specific neutralizing antibody levels compared to individuals of European descent and/or Hispanic ethnicity (p! 0.001). Conclusion Our study provides consistent evidence for racial/ethnic differences in humoral immune response following rubella vaccination. PMID:24530932

Brain function and structure and risk for incident diabetes: The Atherosclerosis Risk in Communities Study.

PubMed

Bancks, Michael P; Alonso, Alvaro; Gottesman, Rebecca F; Mosley, Thomas H; Selvin, Elizabeth; Pankow, James S

2017-12-01

Diabetes is prospectively associated with cognitive decline. Whether lower cognitive function and worse brain structure are prospectively associated with incident diabetes is unclear. We analyzed data for 10,133 individuals with cognitive function testing (1990-1992) and 1212 individuals with brain magnetic resonance imaging (1993-1994) from the Atherosclerosis Risk in Communities cohort. We estimated hazard ratios for incident diabetes through 2014 after adjustment for traditional diabetes risk factors and cohort attrition. Higher level of baseline cognitive function was associated with lower risk for diabetes (per 1 standard deviation, hazard ratio = 0.94; 95% confidence interval = 0.90, 0.98). This association did not persist after accounting for baseline glucose level, case ascertainment methods, and cohort attrition. No association was observed between any brain magnetic resonance imaging measure and incident diabetes. This is one of the first studies to prospectively evaluate the association between both cognitive function and brain structure and the incidence of diabetes. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

The Impact of Multiple Malignancies on Patients with Bladder Carcinoma: A Population-Based Study Using the SEER Database

PubMed Central

Ehrlich, Joshua R.; Schwartz, Michael J.; Ng, Casey K.; Kauffman, Eric C.; Scherr, Douglas S.

2009-01-01

Purpose. To date, no study has examined a population-based registry to determine the impact of multiple malignancies on survival of bladder cancer patients. Our experience suggests that bladder cancer patients with multiple malignancies may have relatively positive outcomes. Materials & Methods. We utilized data from the Surveillance Epidemiology and End Results (SEERs) database to examine survival between patients with only bladder cancer (BO) and with bladder cancer and additional cancer(s) antecedent (AB), subsequent (BS), or antecedent and subsequent to bladder cancer (ABS). Results. Analyses demonstrated diminished survival among AB and ABS cohorts. However, when cohorts were substratified by stage, patients in the high-stage BS cohort appeared to have a survival advantage over high-stage BO patients. Conclusions. Bladder cancer patients with multiple malignancies have diminished survival. The survival advantage of high-stage BS patients is likely a statistical phenomenon. Such findings are important to shape future research and to improve our understanding of patients with multiple malignancies. PMID:20069054

Phenotypic Description of the Spanish Multicentre Genetic Glaucoma Group Cohort

PubMed Central

Gamundi, Maria José; Duch, Susana; Rios, Jose; Carballo, Miguel; Study Group, EMEIGG

2017-01-01

Introduction The aim of the study was to make a phenotypic description of the Spanish multicentre glaucoma group cohort of patients. Design Retrospective, observational, multicentre, cohort study. Material and Methods The clinical charts of 152 patients with hereditary glaucoma from18 Spanish eye centres were reviewed in order to make an epidemiologic description of the type of glaucoma and associated factors. True hereditary cases were compared with familiar cases according to the Gong et al. criteria. Results 61% were true hereditary cases and 39% familiar cases. Ocular comorbidity, optic disc damage, and visual field mean defect were significantly more severe in hereditary patients, who required significantly more first-line hypotensive drugs and surgical interventions to control intraocular pressure than familiar patients. Conclusions The strength of the hereditary component of glaucoma seems to worsen the clinical course, causing more structural and functional damage and requiring more intense glaucoma treatment. The family history of glaucoma should be carefully investigated and taken into consideration when making treatment decisions or intensifying previous treatment. PMID:29082038

EUropean prospective cohort study on Enterobacteriaceae showing REsistance to CArbapenems (EURECA): a protocol of a European multicentre observational study.

PubMed

Gutiérrez-Gutiérrez, Belén; Sojo-Dorado, Jesús; Bravo-Ferrer, José; Cuperus, Nienke; de Kraker, Marlieke; Kostyanev, Tomislav; Raka, Lul; Daikos, George; Feifel, Jan; Folgori, Laura; Pascual, Alvaro; Goossens, Herman; O'Brien, Seamus; Bonten, Marc J M; Rodríguez-Baño, Jesús

2017-04-03

The rapid worldwide spread of carbapenem-resistant Enterobacteriaceae (CRE) constitutes a major challenge. The aim of the EUropean prospective cohort study on Enterobacteriaceae showing REsistance to CArbapenems (EURECA), which is part of the Innovative Medicines Initiative Joint Undertaking (IMI JU) funded COMBACTE-CARE project, is to investigate risk factors for and outcome determinants of CRE infections to inform randomised clinical trial designs and to provide a historical cohort that could eventually be used for future comparisons with new drugs targeting CRE. A multicentre (50 sites), multinational (11 European countries), analytical observational project was designed, comprising 3 studies. The aims of study 1 (a prospective cohort study) include characterising the features, clinical management and outcomes of hospitalised patients with intra-abdominal infection, pneumonia, complicated urinary tract infections and bloodstream infections caused by CRE (202 patients in each group). The main outcomes will be 30-day all-cause mortality and clinical response. Study 2 (a nested case-control study) will identify the risk factors for target infections caused by CRE; 248 selected patients from study 1 will be matched with patients with carbapenem-susceptible Enterobacteriaceae (1:1) and with hospitalised patients (1:3) and will provide a historical cohort of patients with CRE infections. Study 3 (a matched cohort study) will follow patients in study 2 in order to assess mortality, length of stay and hospital costs associated with CRE. All patients will be followed for 30 days. Different, up-to-date statistical methods will be applied to come to unbiased estimates for all 3 studies. Before-study sites will be initiated, approval will be sought from appropriate regulatory agencies and local Ethics Committees of Research or Institutional Review Boards (IRBs) to conduct the study in accordance with regulatory requirements. This is an observational study and therefore no intervention in the diagnosis, management or treatment of the patients will be required on behalf of the investigation. Any formal presentation or publication of data collected from this study will be considered as a joint publication by the participating physician(s) and will follow the recommendations of the International Committee of Medical Journal Editors (ICMJE) for authorship. NCT02709408. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Comparison of surgical outcomes after anterior cervical discectomy and fusion: does the intra-operative use of a microscope improve surgical outcomes

PubMed Central

Elsamadicy, Aladine; Reiser, Elizabeth; Ziegler, Cole; Freischlag, Kyle; Cheng, Joseph; Bagley, Carlos A.

2016-01-01

Background The primary aim of this study was to assess and compare the complications profile as well as long-term clinical outcomes between patients undergoing an Anterior Cervical Discectomy and Fusion (ACDF) procedure with and without the use of an intra-operative microscope. Methods One hundred and forty adult patients (non-microscope cohort: 81; microscope cohort: 59) undergoing ACDF at a major academic medical center were included in this study. Enrollment criteria included available demographic, surgical and clinical outcome data. All patients had prospectively collected patient-reported outcomes measures and a minimum 2-year follow-up. Patients completed the neck disability index (NDI), short-form 12 (SF-12) and visual analog pain scale (VAS) before surgery, then at 3, 6, 12, and 24 months after surgery. Clinical outcomes and complication rates were compared between both patient cohorts. Results Baseline characteristics were similar between both cohorts. The mean ± standard deviation duration of surgery was longer in the microscope cohort (microscope: 169±34 minutes vs. non-microscope: 98±42 minutes, P<0.001). There was no significant difference between cohorts in the incidence of nerve root injury (P=0.99) or incidental durotomy (P=0.32). At 3 months post-operatively, both cohorts demonstrated similar improvement in VAS-neck pain (P=0.69), NDI (P=0.86), SF-12 PCS (P=0.84) and SF-12 MCS (P=0.75). At 2-year post-operatively, both the microscope and non-microscope cohorts demonstrated similar improvement from base line in NDI (microscope: 13.52±25.77 vs. non-microscope: 19.51±27.47, P<0.18), SF-12 PCS (microscope: 4.15±26.39 vs. non-microscope: 11.98±22.96, P<0.07), SF-12 MCS (microscope: 9.47±32.38 vs. non-microscope: 16.19±30.44, P<0.21). Interestingly at 2 years, the change in VAS neck pain score was significantly different between cohorts (microscope: 2.22±4.00 vs. non-microscope: 3.69±3.61, P<0.02). Conclusions Our study demonstrates that the intra-operative use of a microscope does not improve overall surgery-related outcomes, nor does it lead to superior long-term outcomes in pain and functional disability, 2 years after index surgery. PMID:27683692

The peroxisome proliferator-activated receptor agonist pioglitazone and 5-lipoxygenase inhibitor zileuton have no effect on lung inflammation in healthy volunteers by positron emission tomography in a single-blind placebo-controlled cohort study

PubMed Central

Huang, Howard J.; Byers, Derek E.; Shifren, Adrian; Belikoff, Bryan; Engle, Jacquelyn T.; Arentson, Elizabeth; Kemp, Debra; Phillips, Sharon; Scherrer, David E.; Fujiwara, Hideji; Spayd, Katherine J.; Brooks, Frank J.; Pierce, Richard A.; Castro, Mario; Isakow, Warren

2018-01-01

Background Anti-inflammatory drug development efforts for lung disease have been hampered in part by the lack of noninvasive inflammation biomarkers and the limited ability of animal models to predict efficacy in humans. We used 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in a human model of lung inflammation to assess whether pioglitazone, a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, and zileuton, a 5-lipoxygenase inhibitor, reduce lung inflammation. Methods For this single center, single-blind, placebo-controlled cohort study, we enrolled healthy volunteers sequentially into the following treatment cohorts (N = 6 per cohort): pioglitazone plus placebo, zileuton plus placebo, or dual placebo prior to bronchoscopic endotoxin instillation. 18F-FDG uptake pre- and post-endotoxin was quantified as the Patlak graphical analysis-determined Ki (primary outcome measure). Secondary outcome measures included the mean standard uptake value (SUVmean), post-endotoxin bronchoalveolar lavage (BAL) cell counts and differentials and blood adiponectin and urinary leukotriene E4 (LTE4) levels, determined by enzyme-linked immunosorbent assay, to verify treatment compliance. One- or two-way analysis of variance assessed for differences among cohorts in the outcome measures (expressed as mean ± standard deviation). Results Ten females and eight males (29±6 years of age) completed all study procedures except for one volunteer who did not complete the post-endotoxin BAL. Ki and SUVmean increased in all cohorts after endotoxin instillation (Ki increased by 0.0021±0.0019, 0.0023±0.0017, and 0.0024±0.0020 and SUVmean by 0.47±0.14, 0.55±0.15, and 0.54±0.38 in placebo, pioglitazone, and zileuton cohorts, respectively, p<0.001) with no differences among treatment cohorts (p = 0.933). Adiponectin levels increased as expected with pioglitazone treatment but not urinary LTE4 levels as expected with zileuton treatment. BAL cell counts (p = 0.442) and neutrophil percentage (p = 0.773) were similar among the treatment cohorts. Conclusions Endotoxin-induced lung inflammation in humans is not responsive to pioglitazone or zileuton, highlighting the challenge in translating anti-inflammatory drug efficacy results from murine models to humans. Trial registration ClinicalTrials.gov NCT01174056. PMID:29414995

[Mortality in the tire plant workers].

PubMed

Wilczyńska, U; Szadkowska-Stańczyk, I; Szeszenia-Dabrowska, N; Sobala, W; Strzelecka, A

2000-01-01

This paper describes a cohort study of the mortality among workers employed in one of Polish tyre plants. The scope of the study was limited to the analysis of mortality from main disease categories. Mortality from particular cancer sites will be discussed in a separate publication. The cohort comprised 17,747 workers (11,660 men and 6,087 women) employed during the years 1950-95 for at least three months in the tyre plant. As of 31 December 1995, the follow-up of the cohort was completed. A detailed analysis of mortality by causes was carried out using standardised mortality ratio (SMR) calculated by the person-years method. The general population of Poland was used as the reference. The results indicated general mortality significantly lower in the cohort (men: SMR = 72; women: SMR = 62), than in the reference population. The number of observed deaths from main disease categories was also lower than those expected. The analysis by specific causes revealed significant excess of deaths, due to hypertensive disease among men (36 deaths, SMR = 142; 95% CI: 99-197). SMRs were also calculated in sub-cohorts identified by activities performed (preparatory works: production of tyres and inner tubes; maintenance; storage; others). General mortality in sub-cohorts was similar to that in the total cohort. After analysis by causes of death, some non-significant excess mortality could be observed. It was very small or it applied only to single cases of death. Excess mortality from hypertensive disease in male maintenance workers (21 deaths, SMR = 262; 95% CI: 162-400) was the only exception. The absence of adverse health effects pronounced by significant excess mortality should be attributed to a relatively short period of exposure among the majority of the followed-up workers (over 58% of workers in the cohort employed in the plant for a period shorter than five years) and to their young age. Almost 56% of workers in the cohort were born in the 1950s or later which means that at the end of the follow-up they were not older than 45 years. In order to complete the final mortality assessment the follow-up should continue.

Operationalizing multimorbidity and autonomy for health services research in aging populations - the OMAHA study

PubMed Central

2011-01-01

Background As part of a Berlin-based research consortium on health in old age, the OMAHA (Operationalizing Multimorbidity and Autonomy for Health Services Research in Aging Populations) study aims to develop a conceptual framework and a set of standardized instruments and indicators for continuous monitoring of multimorbidity and associated health care needs in the population 65 years and older. Methods/Design OMAHA is a longitudinal epidemiological study including a comprehensive assessment at baseline and at 12-month follow-up as well as brief intermediate telephone interviews at 6 and 18 months. In order to evaluate different sampling procedures and modes of data collection, the study is conducted in two different population-based samples of men and women aged 65 years and older. A geographically defined sample was recruited from an age and sex stratified random sample from the register of residents in Berlin-Mitte (Berlin OMAHA study cohort, n = 299) for assessment by face-to-face interview and examination. A larger nationwide sample (German OMAHA study cohort, n = 730) was recruited for assessment by telephone interview among participants in previous German Telephone Health Surveys. In both cohorts, we successfully applied a multi-dimensional set of instruments to assess multimorbidity, functional disability in daily life, autonomy, quality of life (QoL), health care services utilization, personal and social resources as well as socio-demographic and biographical context variables. Response rates considerably varied between the Berlin and German OMAHA study cohorts (22.8% vs. 59.7%), whereas completeness of follow-up at month 12 was comparably high in both cohorts (82.9% vs. 81.2%). Discussion The OMAHA study offers a wide spectrum of data concerning health, functioning, social involvement, psychological well-being, and cognitive capacity in community-dwelling older people in Germany. Results from the study will add to methodological and content-specific discourses on human resources for maintaining quality of life and autonomy throughout old age, even in the face of multiple health complaints. PMID:21352521

Classification of patients with sepsis according to blood genomic endotype: a prospective cohort study.

PubMed

Scicluna, Brendon P; van Vught, Lonneke A; Zwinderman, Aeilko H; Wiewel, Maryse A; Davenport, Emma E; Burnham, Katie L; Nürnberg, Peter; Schultz, Marcus J; Horn, Janneke; Cremer, Olaf L; Bonten, Marc J; Hinds, Charles J; Wong, Hector R; Knight, Julian C; van der Poll, Tom

2017-10-01

Host responses during sepsis are highly heterogeneous, which hampers the identification of patients at high risk of mortality and their selection for targeted therapies. In this study, we aimed to identify biologically relevant molecular endotypes in patients with sepsis. This was a prospective observational cohort study that included consecutive patients admitted for sepsis to two intensive care units (ICUs) in the Netherlands between Jan 1, 2011, and July 20, 2012 (discovery and first validation cohorts) and patients admitted with sepsis due to community-acquired pneumonia to 29 ICUs in the UK (second validation cohort). We generated genome-wide blood gene expression profiles from admission samples and analysed them by unsupervised consensus clustering and machine learning. The primary objective of this study was to establish endotypes for patients with sepsis, and assess the association of these endotypes with clinical traits and survival outcomes. We also established candidate biomarkers for the endotypes to allow identification of patient endotypes in clinical practice. The discovery cohort had 306 patients, the first validation cohort had 216, and the second validation cohort had 265 patients. Four molecular endotypes for sepsis, designated Mars1-4, were identified in the discovery cohort, and were associated with 28-day mortality (log-rank p=0·022). In the discovery cohort, the worst outcome was found for patients classified as having a Mars1 endotype, and at 28 days, 35 (39%) of 90 people with a Mars1 endotype had died (hazard ratio [HR] vs all other endotypes 1·86 [95% CI 1·21-2·86]; p=0·0045), compared with 23 (22%) of 105 people with a Mars2 endotype (HR 0·64 [0·40-1·04]; p=0·061), 16 (23%) of 71 people with a Mars3 endotype (HR 0·71 [0·41-1·22]; p=0·19), and 13 (33%) of 40 patients with a Mars4 endotype (HR 1·13 [0·63-2·04]; p=0·69). Analysis of the net reclassification improvement using a combined clinical and endotype model significantly improved risk prediction to 0·33 (0·09-0·58; p=0·008). A 140-gene expression signature reliably stratified patients with sepsis to the four endotypes in both the first and second validation cohorts. Only Mars1 was consistently significantly associated with 28-day mortality across the cohorts. To facilitate possible clinical use, a biomarker was derived for each endotype; BPGM and TAP2 reliably identified patients with a Mars1 endotype. This study provides a method for the molecular classification of patients with sepsis to four different endotypes upon ICU admission. Detection of sepsis endotypes might assist in providing personalised patient management and in selection for trials. Center for Translational Molecular Medicine, Netherlands. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sport and Other Motor Activities of Warsaw Students

ERIC Educational Resources Information Center

Biernat, Elzbieta

2011-01-01

Study aim: To assess the engagement of students of Warsaw university schools in sports and in recreational motor activities. Material and methods: A cohort (n = 1100) of students attending B.S. or M.S. courses at 6 university schools in Warsaw were studied by applying questionnaire techniques. The questions pertained to participation in…

Predictors of direct cost of diabetes care in pediatric patients with type 1 diabetes

USDA-ARS?s Scientific Manuscript database

This study examines factors that predict elevated direct costs of pediatric patients with type 1 diabetes. Methods: A cohort of 784 children with type 1 diabetes at least 6 months postdiagnosis and managed by pediatric endocrinologists at Texas Children's Hospital were included in this study. Actual...

Physician Assistants and Nurse Practitioners as a Usual Source of Care

ERIC Educational Resources Information Center

Everett, Christine M.; Schumacher, Jessica R.; Wright, Alexandra; Smith, Maureen A.

2009-01-01

Purpose: To identify characteristics and outcomes of patients who use physician assistants and nurse practitioners (PA/NPs) as a usual source of care. Methods: Cross sectional analysis using the telephone and mail surveys of the Wisconsin Longitudinal Study (WLS), a prospective cohort study of Wisconsin high school graduates and selected siblings…

Data Sharing and Reuse within the Academic Pathways Study

ERIC Educational Resources Information Center

Toye, George; Sheppard, Sheri; Chen, Helen L.

2016-01-01

The Academic Pathway Study (APS) research program within National Science Foundation (NSF) Center for Advancement of Engineering Education (CAEE) ran from 2003-2010. It amassed a collection of longitudinal as well as cross-sectional data sets, of varying research method types and formats, from four different primary cohorts that included over…

Residential Modifications and Decline in Physical Function among Community-Dwelling Older Adults

ERIC Educational Resources Information Center

Liu, Sze Y.; Lapane, Kate L.

2009-01-01

Purpose: The purpose of this study is to quantify the effect of residential modification on decreasing risk of physical function decline in 2 years. Design: Cohort study using propensity scores method to control for baseline differences between individuals with residential modifications and those without residential modifications. Participants:…

Risk Factors for Rural Residential Fires

ERIC Educational Resources Information Center

Allareddy, Veerasathpurush; Peek-Asa, Corinne; Yang, Jingzhen; Zwerling, Craig

2007-01-01

Context and Purpose: Rural households report high fire-related mortality and injury rates, but few studies have examined the risk factors for fires. This study aims to identify occupant and household characteristics that are associated with residential fires in a rural cohort. Methods: Of 1,005 households contacted in a single rural county, 691…

National observatory on the therapeutic management in ambulatory care patients aged 65 and over, with type 2 diabetes, chronic pain or atrial fibrillation.

PubMed

Becquemont, Laurent; Benattar-Zibi, Linda; Bertin, Philippe; Berrut, Gilles; Corruble, Emmanuelle; Danchin, Nicolas; Delespierre, Tiba; Derumeaux, Geneviève; Falissard, Bruno; Forette, Francoise; Hanon, Olivier; Pasquier, Florence; Pinget, Michel; Ourabah, Rissane; Piedvache, Céline

2013-01-01

The primary objective of the S.AGES cohort is to describe the real-life therapeutic care of elderly patients. Patients and methods. This is a prospective observational cohort study of 3 700 non-institutionalized patients over the age of 65 years with either type 2 diabetes mellitus (T2DM), chronic pain or atrial fibrillation (AF) recruited by French general practitioners (GPs). Follow-up is planned for 3 years. Baseline characteristics. In the chronic pain sub-cohort, 33% of patients are treated with only grade 1 analgesics, 29% with grade 2 analgesics and 3% with grade 3 analgesics, and 22% have no pain treatment. In the T2DM sub-cohort, 61% of patients have well-controlled diabetes (Hb1c<7%) and 18% are treated with insulin. In the AF sub-cohort, 65% of patients have a CHADS2 score greater than 2, 77% are treated with oral anticoagulants, 17% with platelet inhibitors, 40% with antiarrhythmic drugs and 56% with rate slowing medications. Conclusion. The S.AGES cohort presents a unique opportunity to clarify the real-life therapeutic management of ambulatory elderly subjects and will help to identify the factors associated with the occurrence of major clinical events. © 2013 Société Française de Pharmacologie et de Thérapeutique.

Cohorts, Communities of Inquiry, and Course Delivery Methods: UTC Best Practices in Learning--The Hybrid Learning Community Model

ERIC Educational Resources Information Center

Rausch, David W.; Crawford, Elizabeth K.

2012-01-01

From the early 1990s to present, the practice of cohort-based learning has been on the rise in colleges, universities, organizations, and even some K-12 programs across the nation. This type of learning model uses the power of the interpersonal relationships to enhance the learning process and provide additional support to the cohort members as…

Mortality among people who inject drugs: a systematic review and meta-analysis

PubMed Central

Degenhardt, Louisa; Bucello, Chiara; Lemon, James; Wiessing, Lucas; Hickman, Mathew

2013-01-01

Abstract Objective To systematically review cohort studies of mortality among people who inject drugs, examine mortality rates and causes of death in this group, and identify participant- and study-level variables associated with a higher risk of death. Methods Tailored search strings were used to search EMBASE, Medline and PsycINFO. The grey literature was identified through online grey literature databases. Experts were consulted to obtain additional studies and data. Random effects meta-analyses were performed to estimate pooled crude mortality rates (CMRs) and standardized mortality ratios (SMRs). Findings Sixty-seven cohorts of people who inject drugs were identified, 14 of them from low- and middle-income countries. The pooled CMR was 2.35 deaths per 100 person–years (95% confidence interval, CI: 2.12–2.58). SMRs were reported for 32 cohorts; the pooled SMR was 14.68 (95% CI: 13.01–16.35). Comparison of CMRs and the calculation of CMR ratios revealed mortality to be higher in low- and middle-income country cohorts, males and people who injected drugs that were positive for human immunodeficiency virus (HIV). It was also higher during off-treatment periods. Drug overdose and acquired immunodeficiency syndrome (AIDS) were the primary causes of death across cohorts. Conclusion Compared with the general population, people who inject drugs have an elevated risk of death, although mortality rates vary across different settings. Any comprehensive approach to improving health outcomes in this group must include efforts to reduce HIV infection as well as other causes of death, particularly drug overdose. PMID:23554523

Risk of Suicide Attempt in Poststroke Patients: A Population-Based Cohort Study.

PubMed

Harnod, Tomor; Lin, Cheng-Li; Kao, Chia-Hung

2018-01-10

This nationwide population-based cohort study evaluated the risk of and risk factors for suicide attempt in poststroke patients in Taiwan. The poststroke and nonstroke cohorts consisted of 713 690 patients and 1 426 009 controls, respectively. Adults (aged >18 years) who received new stroke diagnoses according to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM ; codes 430-438) between 2000 and 2011 were included in the poststroke cohort. We calculated the adjusted hazard ratio for suicide attempt ( ICD-9-CM codes E950-E959) after adjustment for age, sex, monthly income, urbanization level, occupation category, and various comorbidities. Kaplan-Meier analysis was used to measure the cumulative incidence of suicide attempt, and the Fine and Gray method was used as a competing event when estimating death subhazard ratios and 95% confidence intervals between groups. The cumulative incidence of suicide attempt was higher in the poststroke cohort, and the adjusted hazard ratio of suicide attempt was 2.20 (95% confidence interval, 2.04-2.37) compared with that of the controls. The leading risk factors for poststroke suicide attempt were earning low monthly income (<660 US dollars), living in less urbanized regions, doing manual labor, and having a stroke before age 50 years. The attempted suicide risk did not differ significantly between male and female patients in this study. These results convey crucial information to clinicians and governments for preventing suicide attempt in poststroke patients in Taiwan and other Asian countries. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Factors Associated with Breastfeeding Initiation: A Comparison between France and French-Speaking Canada

PubMed Central

Girard, Lisa-Christine; Côté, Sylvana M.; de Lauzon-Guillain, Blandine; Dubois, Lise; Falissard, Bruno; Forhan, Anne; Doyle, Orla; Bernard, Jonathan Y.; Heude, Barbara; Saurel-Cubizolles, Marie-Josephe; Kaminski, Monique; Boivin, Michel; Tremblay, Richard E.

2016-01-01

Background Breastfeeding is associated with multiple domains of health for both mothers and children. Nevertheless, breastfeeding initiation is low within certain developed countries. Furthermore, comparative studies of initiation rates using harmonised data across multiple regions is scarce. Objective The aim of the present study was to investigate and compare individual-level determinants of breastfeeding initiation using two French-speaking cohorts. Methods Participants included ~ 3,900 mothers enrolled in two cohort studies in Canada and France. Interviews, questionnaires, and medical records were utilised to collect information on maternal, family, and medical factors associated with breastfeeding initiation. Results Rates of breastfeeding initiation were similar across cohorts, slightly above 70%. Women in both Canada and France who had higher levels of maternal education, were born outside of their respective countries and who did not smoke during pregnancy were more likely to initiate breastfeeding with the cohort infant. Notably, cohort effects of maternal education at the university level were found, whereby having ‘some university’ was not statistically significant for mothers in France. Further, younger mothers in Canada, who delivered by caesarean section and who had previous children, had reduced odds of breastfeeding initiation. These results were not found for mothers in France. Conclusions and Implications for Practice While some similar determinants were observed, programming efforts to increase breastfeeding initiation should be tailored to the characteristics of specific geographical regions which may be heavily impacted by the social, cultural and political climate of the region, in addition to individual and family level factors. PMID:27902741

Social Withdrawal Behaviour at One Year of Age Is Associated with Delays in Reaching Language Milestones in the EDEN Mother-Child Cohort Study

PubMed Central

Guedeney, Antoine; Forhan, Anne; de Agostini, Maria; Pingault, Jean-Baptiste; Heude, Barbara

2016-01-01

Objective The aim of the study was to examine the relationship between social withdrawal behaviour at one year and motor and language milestones. Materials and Methods One-year old children from the EDEN French population-based birth cohort study (Study on the pre- and postnatal determinants of the child’s development and prospective health Birth Cohort Study) were included. Social withdrawal at one year was assessed by trained midwives using the Alarm Distress BaBy (ADBB) scale. Midwives concurrently examined infants’ motor and language milestones. Parents reported on child’s psychomotor and language milestones, during the interview with the midwife. Results After adjusting for potential confounding factors, social withdrawal behaviour was significantly associated with concurrent delays in motor and language milestones assessed by the midwife or the parents. Discussion Higher scores on social withdrawal behaviour as assessed with the ADBB were associated with delays in reaching language milestones, and to a lesser extent with lower motor ability scores. Taking the contribution of social withdrawal behaviour into account may help understand the unfolding of developmental difficulties in children. PMID:27391482

Seremban Cohort Study (SECOST): a prospective study of determinants and pregnancy outcomes of maternal glycaemia in Malaysia

PubMed Central

Mohd Shariff, Zalilah; Rejali, Zulida; Mohd Yusof, Barakatun Nisak; Yasmin, Farah; Palaniveloo, Lalitha

2018-01-01

Introduction Both gestational diabetes mellitus (GDM) and hyperglycaemia less severe than GDM are associated with risk of adverse pregnancy outcomes. We describe the study design of a prospective cohort of pregnant women recruited in early pregnancy with follow-ups of mothers and infants up to 2 years after birth. The primary aim of the study was to identify the determinants and outcomes of maternal glycaemia. Methods and analysis Seremban Cohort Study (SECOST) is an ongoing prospective cohort study in which eligible pregnant women in first trimester (<10 weeks of gestation) are recruited from Maternal and Child Health clinics in Seremban District, Negeri Sembilan with seven follow-ups during pregnancy through 2 years postnatally. Infants are followed up every 6 months after birth until 2 years old. A standard 75 g oral glucose tolerance test is performed between 24 and 32 of weeks of gestation and as close to 28 weeks of gestation. Pregnancy and birth information are obtained from medical records. Sociodemographic, anthropometric, biochemical, dietary, physical activity, smoking, depression, child feeding and other data of mothers and infants are obtained at follow-ups. Ethics and dissemination This study is approved by the Medical Research Ethics Committee (MREC), Universiti Putra Malaysia (UPM/FPSK/100-9/2-MJKEtika) and MREC, Ministry of Health Malaysia (KKM/NIHSEC/08/0804/P12- 613). Permission to conduct this study is also obtained from the Head of Seremban District Health Office. All participants are required to provide written informed consent prior to data collection. The research findings will be disseminated at journals and conference presentations. PMID:29358431

Impact of a Required Pharmaceutical Calculations Course on Mathematics Ability and Knowledge Retention

PubMed Central

Buring, Shauna M.; Papas, Elizabeth

2013-01-01

Objective. To assess doctor of pharmacy (PharmD) students’ mathematics ability by content area before and after completing a required pharmaceutical calculations course and to analyze changes in scores. Methods. A mathematics skills assessment was administered to 2 cohorts of pharmacy students (class of 2013 and 2014) before and after completing a pharmaceutical calculations course. The posttest was administered to the second cohort 6 months after completing the course to assess knowledge retention. Results. Both cohorts performed significantly better on the posttest (cohort 1, 13% higher scores; cohort 2, 15.9% higher scores). Significant improvement on posttest scores was observed in 6 of the 10 content areas for cohorts 1 and 2. Both cohorts scored lower in percentage calculations on the posttest than on the pretest. Conclusions. A required, 1-credit-hour pharmaceutical calculations course improved PharmD students’ overall ability to perform fundamental and application-based calculations. PMID:23966727

Risk of Infection After Allograft Anterior Cruciate Ligament Reconstruction: Are Nonprocessed Allografts More Likely to Get Infected? A Cohort Study of Over 10,000 Allografts.

PubMed

Yu, Anthony; Prentice, Heather A; Burfeind, William E; Funahashi, Tadashi; Maletis, Gregory B

2018-03-01

Allograft tissue is frequently used in anterior cruciate ligament reconstruction (ACLR). It is often irradiated and/or chemically processed to decrease the risk of disease transmission, but some tissue is aseptically harvested without further processing. Irradiated and chemically processed allograft tissue appears to have a higher risk of revision, but whether this processing decreases the risk of infection is not clear. To determine the incidence of deep surgical site infection after ACLR with allograft in a large community-based sample and to evaluate the association of allograft processing and the risk of deep infection. Cohort study; Level of evidence, 3. The authors conducted a cohort study using the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry. Primary isolated unilateral ACLR with allograft were identified from February 1, 2005 to September 30, 2015. Ninety-day postoperative deep infections were identified via an electronic screening algorithm and then validated through chart review. Logistic regression was used to evaluate the likelihood of 90-day postoperative deep infection per allograft processing method: processed (graft treated chemically and/or irradiated) or nonprocessed (graft not irradiated or chemically processed). Of 10,190 allograft cases, 8425 (82.7%) received a processed allograft, and 1765 (17.3%) received a nonprocessed allograft. There were 15 (0.15%) deep infections during the study period: 4 (26.7%) coagulase-negative Staphylococcus, 4 (26.7%) methicillin-sensitive Staphylococcus aureus, 1 (6.7%) Peptostreptococcus micros, and 6 (40.0%) with no growth. There was no difference in the likelihood for 90-day deep infection for processed versus nonprocessed allografts (odds ratio = 1.36, 95% CI = 0.31-6.04). The overall incidence of deep infection after ACLR with allograft tissue was very low (0.15%), suggesting that the methods currently employed by tissue banks to minimize the risk of infection are effective. In this cohort, no difference in the likelihood of infection between processed and nonprocessed allografts could be identified.

Patient-Reported Outcomes of Periacetabular Osteotomy from the Prospective ANCHOR Cohort Study

PubMed Central

Clohisy, John C.; Ackerman, Jeffrey; Baca, Geneva; Baty, Jack; Beaulé, Paul E.; Kim, Young-Jo; Millis, Michael B.; Podeszwa, David A.; Schoenecker, Perry L.; Sierra, Rafael J.; Sink, Ernest L.; Sucato, Daniel J.; Trousdale, Robert T.; Zaltz, Ira

2017-01-01

Background: Current literature describing the periacetabular osteotomy (PAO) is mostly limited to retrospective case series. Larger, prospective cohort studies are needed to provide better clinical evidence regarding this procedure. The goals of the current study were to (1) report minimum 2-year patient-reported outcomes (pain, hip function, activity, overall health, and quality of life), (2) investigate preoperative clinical and disease characteristics as predictors of clinical outcomes, and (3) report the rate of early failures and reoperations in patients undergoing contemporary PAO surgery. Methods: A large, prospective, multicenter cohort of PAO procedures was established, and outcomes at a minimum of 2 years were analyzed. A total of 391 hips were included for analysis (79% of the patients were female, and the average patient age was 25.4 years). Patient-reported outcomes, conversion to total hip replacement, reoperations, and major complications were documented. Variables with a p value of ≤0.10 in the univariate linear regressions were included in the multivariate linear regression. The backward stepwise selection method was used to determine the final risk factors of clinical outcomes. Results: Clinical outcome analysis demonstrated major clinically important improvements in pain, function, quality of life, overall health, and activity level. Increasing age and a body mass index status of overweight or obese were predictive of improved results for certain outcome metrics. Male sex and mild acetabular dysplasia were predictive of lesser improvements in certain outcome measures. Three (0.8%) of the hips underwent early conversion to total hip arthroplasty, 12 (3%) required reoperation, and 26 (7%) experienced a major complication. Conclusions: This large, prospective cohort study demonstrated the clinical success of contemporary PAO surgery for the treatment of symptomatic acetabular dysplasia. Patient and disease characteristics demonstrated predictive value that should be considered in surgical decision-making. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. PMID:28060231

Use of risk projection models to estimate mortality and incidence from radiation-induced breast cancer in screening programs

NASA Astrophysics Data System (ADS)

Ramos, M.; Ferrer, S.; Villaescusa, J. I.; Verdú, G.; Salas, M. D.; Cuevas, M. D.

2005-02-01

The authors report on a method to calculate radiological risks, applicable to breast screening programs and other controlled medical exposures to ionizing radiation. In particular, it has been applied to make a risk assessment in the Valencian Breast Cancer Early Detection Program (VBCEDP) in Spain. This method is based on a parametric approach, through Markov processes, of hazard functions for radio-induced breast cancer incidence and mortality, with mean glandular breast dose, attained age and age-at-exposure as covariates. Excess relative risk functions of breast cancer mortality have been obtained from two different case-control studies exposed to ionizing radiation, with different follow-up time: the Canadian Fluoroscopy Cohort Study (1950-1987) and the Life Span Study (1950-1985 and 1950-1990), whereas relative risk functions for incidence have been obtained from the Life Span Study (1958-1993), the Massachusetts tuberculosis cohorts (1926-1985 and 1970-1985), the New York post-partum mastitis patients (1930-1981) and the Swedish benign breast disease cohort (1958-1987). Relative risks from these cohorts have been transported to the target population undergoing screening in the Valencian Community, a region in Spain with about four and a half million inhabitants. The SCREENRISK software has been developed to estimate radiological detriments in breast screening. Some hypotheses corresponding to different screening conditions have been considered in order to estimate the total risk associated with a woman who takes part in all screening rounds. In the case of the VBCEDP, the total radio-induced risk probability for fatal breast cancer is in a range between [5 × 10-6, 6 × 10-4] versus the natural rate of dying from breast cancer in the Valencian Community which is 9.2 × 10-3. The results show that these indicators could be included in quality control tests and could be adequate for making comparisons between several screening programs.

Characterisation of exposure to non-ionising electromagnetic fields in the Spanish INMA birth cohort: study protocol.

PubMed

Gallastegi, Mara; Guxens, Mònica; Jiménez-Zabala, Ana; Calvente, Irene; Fernández, Marta; Birks, Laura; Struchen, Benjamin; Vrijheid, Martine; Estarlich, Marisa; Fernández, Mariana F; Torrent, Maties; Ballester, Ferrán; Aurrekoetxea, Juan J; Ibarluzea, Jesús; Guerra, David; González, Julián; Röösli, Martin; Santa-Marina, Loreto

2016-02-18

Analysis of the association between exposure to electromagnetic fields of non-ionising radiation (EMF-NIR) and health in children and adolescents is hindered by the limited availability of data, mainly due to the difficulties on the exposure assessment. This study protocol describes the methodologies used for characterising exposure of children to EMF-NIR in the INMA (INfancia y Medio Ambiente- Environment and Childhood) Project, a prospective cohort study. Indirect (proximity to emission sources, questionnaires on sources use and geospatial propagation models) and direct methods (spot and fixed longer-term measurements and personal measurements) were conducted in order to assess exposure levels of study participants aged between 7 and 18 years old. The methodology used varies depending on the frequency of the EMF-NIR and the environment (homes, schools and parks). Questionnaires assessed the use of sources contributing both to Extremely Low Frequency (ELF) and Radiofrequency (RF) exposure levels. Geospatial propagation models (NISMap) are implemented and validated for environmental outdoor sources of RFs using spot measurements. Spot and fixed longer-term ELF and RF measurements were done in the environments where children spend most of the time. Moreover, personal measurements were taken in order to assess individual exposure to RF. The exposure data are used to explore their relationships with proximity and/or use of EMF-NIR sources. Characterisation of the EMF-NIR exposure by this combination of methods is intended to overcome problems encountered in other research. The assessment of exposure of INMA cohort children and adolescents living in different regions of Spain to the full frequency range of EMF-NIR extends the characterisation of environmental exposures in this cohort. Together with other data obtained in the project, on socioeconomic and family characteristics and development of the children and adolescents, this will enable to evaluate the complex interaction between health outcomes in children and adolescents and the various environmental factors that surround them.

Immortal time bias in drug safety cohort studies: spontaneous abortion following nonsteroidal antiinflammatory drug exposure.

PubMed

Daniel, Sharon; Koren, Gideon; Lunenfeld, Eitan; Levy, Amalia

2015-03-01

Experimental research of drug safety in pregnancy is generally not feasible because of ethical issues. Therefore, most of the information about drug safety in general and teratogenicity in particular is obtained through observational studies, which require careful methodologic design to obtain unbiased results. Immortal time bias occurs when some cases do not "survive" sufficient time in the study, and as such, they have reduced chances of being defined as "exposed" simply because the durations of their follow-ups were shorter. For example, studies that examine the risk for spontaneous abortions in women exposed to a drug during pregnancy are susceptible to immortal time bias because the chance of drug exposure increases the longer a pregnancy lasts. Therefore, the drug tested may falsely be found protective against the outcome tested. The objective of the current study was to illustrate the extent of immortal time bias using a cohort study of pregnancies assessing the risk for spontaneous abortions following nonsteroidal antiinflammatory drug exposure. We assembled 3 databases containing data on spontaneous abortions, births and drug dispensions to create the present study's cohort. The risk for spontaneous abortion was assessed using 2 statistical analysis methods that were compared for 2 definitions of exposure (dichotomous, exposed vs unexposed, regular Cox regression vs Cox regression with time-varying exposure). Significant differences were found in the risk for spontaneous abortions between the 2 statistical methods, both for groups and for most specific nonsteroidal antiinflammatory drugs (nonselective Cox inhibitors - hazard ratio, 0.70; 95% confidence interval, 0.61-0.94 vs hazard ratio, 1.10; 95% confidence interval, 0.99-1.22 for dichotomous vs time-varying exposure analyses, respectively). Furthermore, a significant correlation was found between the median misclassified immortal time for each drug and the extent of the bias. Immortal time bias can easily occur in cohort studies assessing the risk for adverse pregnancy outcomes following exposure to drugs. One way to prevent such a bias is by defining exposure only from the time of exposure during follow-up onward using a time-varying exposure analysis. Copyright © 2015 Elsevier Inc. All rights reserved.

Interactive Cohort Identification of Sleep Disorder Patients Using Natural Language Processing and i2b2.

PubMed

Chen, W; Kowatch, R; Lin, S; Splaingard, M; Huang, Y

2015-01-01

Nationwide Children's Hospital established an i2b2 (Informatics for Integrating Biology & the Bedside) application for sleep disorder cohort identification. Discrete data were gleaned from semistructured sleep study reports. The system showed to work more efficiently than the traditional manual chart review method, and it also enabled searching capabilities that were previously not possible. We report on the development and implementation of the sleep disorder i2b2 cohort identification system using natural language processing of semi-structured documents. We developed a natural language processing approach to automatically parse concepts and their values from semi-structured sleep study documents. Two parsers were developed: a regular expression parser for extracting numeric concepts and a NLP based tree parser for extracting textual concepts. Concepts were further organized into i2b2 ontologies based on document structures and in-domain knowledge. 26,550 concepts were extracted with 99% being textual concepts. 1.01 million facts were extracted from sleep study documents such as demographic information, sleep study lab results, medications, procedures, diagnoses, among others. The average accuracy of terminology parsing was over 83% when comparing against those by experts. The system is capable of capturing both standard and non-standard terminologies. The time for cohort identification has been reduced significantly from a few weeks to a few seconds. Natural language processing was shown to be powerful for quickly converting large amount of semi-structured or unstructured clinical data into discrete concepts, which in combination of intuitive domain specific ontologies, allows fast and effective interactive cohort identification through the i2b2 platform for research and clinical use.

Rationale, Design, and Profiles of the New Integrated Suburban Seniority Investigation (NISSIN) Project: A Study of an Age-Specific, Community-Based Cohort of Japanese Elderly

PubMed Central

Kitamura, Tetsuhisa; Kawamura, Takashi; Tamakoshi, Akiko; Wakai, Kenji; Ando, Masahiko; Ohno, Yoshiyuki

2009-01-01

Background Although there have been many studies on aging in a number of developed countries, data on the effects of aging during early senescence are scarce. We designed a study to investigate an age-specific cohort in a suburban Japanese city to determine the factors that contribute to living long and well. Methods In every year from 1996 through 2005, residents of Nissin City, Japan who were about to reach the age of 65 years participated in health check-ups and completed a baseline self-administered questionnaire that included items on demographic and lifestyle characteristics, physical function, and quality of life. When the participants reached 70 years of age, they underwent secondary health check-ups at the same site, or received home visits from public health nurses, and their health-related outcomes were noted. Results A total of 3073 64-year-olds were enrolled in the study (response rate, 43.9%). There was considerable intersexual variation in demographic and lifestyle factors. Among men and women, 24.3% and 3.0% were current smokers, respectively, and 68.7% and 19.5% were current alcohol drinkers. Cohort members were in slightly better physical condition than the Japanese general population: they were less likely to be obese and hypertensive and more likely to have 20 teeth or more. Follow-up of the cohort is ongoing. Conclusions We have established a unique age-specific cohort with a consecutive entry–exit system. This project should provide data on early changes in health and related factors in this new era of longevity. PMID:19652444

The safety and adequacy of antithrombotic therapy for atrial fibrillation: a regional cohort study

PubMed Central

Burton, Chris; Isles, Chris; Norrie, John; Hanson, Ruth; Grubb, Elaine

2006-01-01

Background Atrial fibrillation is a common problem in older people. The evidence base for the safety of warfarin and aspirin in atrial fibrillation is largely derived from selective research studies and secondary care. Further assessment of the safety of warfarin in older people with atrial fibrillation in routine primary care is needed. Aim To measure the complication rates and adequacy of warfarin control in a cohort of patients with atrial fibrillation managed in primary care and compare them with published data from controlled trials and community patients with atrial fibrillation not receiving warfarin. Design of study Retrospective review of regional cohort. Setting Twenty-seven general practices in southwest Scotland. Method Case note review of 601 patients previously identified as having atrial fibrillation by GPs. Results The average age of our cohort was 77 years at recruitment. Two hundred and sixty-four (44%) patients died within 5 years of follow up. Three hundred and nine of the 601 (51%) patients with atrial fibrillation took warfarin at some stage during this study. INR (international normalised ratio) was maintained between 2 and 3 for 68% of the time. Bleeding risk was higher in patients taking warfarin than in those on aspirin or no antithrombotic therapy (warfarin 9.0% per year versus aspirin 4.7% per year versus no therapy 4.6% per year). The annual risk of any bleeding complication on warfarin (9%) was similar to that recorded in randomised trials (9.2%) whereas the annual risk of severe bleeding was approximately double (2.6 versus 1.3%). Conclusion Adequacy of anticoagulant control was broadly comparable to that reported in clinical trials, whereas the risk of severe bleeding was higher, possibly reflecting the older age and the comorbidities of our unselected cohort. PMID:16954003

Population-based breast cancer screening in a primary care network

PubMed Central

Atlas, Steven J.; Ashburner, Jeffrey M.; Chang, Yuchiao; Lester, William T.; Barry, Michael J.; Grant, Richard W.

2013-01-01

Objective To assess up to 3-year follow-up of a health information technology system that facilitated population-based breast cancer screening. Study Design Cohort study with 2-year follow-up after completing a 1-year cluster randomized trial. Methods Women 42-69 years old receiving care within a 12-practice primary care network. The trial tested an integrated, non-visit-based population management informatics system that: 1) identified women overdue for mammograms, 2) connected them to primary care providers using a Web-based tool, 3) created automatically-generated outreach letters for patients specified by providers, 4) monitored for subsequent mammography scheduling and completion, and 5) provided practice delegates a list of women remaining unscreened for reminder phone calls. All practices also provided visit-based cancer screening reminders. Eligible women overdue for a mammogram during a one-year study period included those overdue at study start (prevalent cohort) or becoming overdue during follow-up (incident cohort). The main outcome measure was mammography completion rates over three years. Results Among 32,688 eligible women, 9,795 (30%) were overdue for screening including 4,487 in intervention and 5,308 in control practices. Intervention patients were somewhat younger, more likely to be non-Hispanic white, and have health insurance compared to control patients. Among patients in the prevalent cohort (n=6,697), adjusted completion rates were significantly higher among intervention compared to control patients after 3 years (51.7% vs. 45.8%, p=0.002). For patients in the incident cohort (n=3,098), adjusted completion rates after 2 years were 53.8% vs. 48.7%, p=0.052, respectively. Conclusions Population-based informatics systems can enable sustained increases in mammography screening rates beyond that seen with office-based visit reminders. PMID:23286611

Recruitment and enrollment of African Americans into health promoting programs: the effects of health promoting programs on cardiovascular disease risk study.

PubMed

Okhomina, Victoria I; Seals, Samantha R; Marshall, Gailen D

2018-04-03

Randomized controlled trials (RCT) often employ multiple recruitment methods to attract participants, however, special care must be taken to be inclusive of under-represented populations. We examine how recruiting from an existing observational study affected the recruitment of African Americans into a RCT that included yoga-based interventions. In particular, we report the recruitment success of The Effects of Health Promoting Programs (HPP) on Cardiovascular Disease Risk (NCT02019953), the first yoga-based clinical trial to focus only on African Americans. To recruit participants, a multifaceted recruitment strategy was implemented exclusively in the Jackson Heart Study (JHS) cohort. The HPP recruited from the JHS cohort using direct mailings, signs and flyers placed around JHS study facilities, and through JHS annual follow-up interviews. Enrollment into HPP was open to all active JHS participants that were eligible to return for the third clinic exam (n = 4644). The target sample size was 375 JHS participants over a 24 month recruitment and enrollment period. From the active members of the JHS cohort, 503 were pre-screened for eligibility in HPP. More than 90% of those pre-screened were provisionally eligible for the study. The enrollment goal of 375 was completed after a 16-month enrollment period with over 25% (n = 97) of the required sample size enrolling during the second month of recruitment. The findings show that participants in observational studies can be successfully recruited into RCT. Observational studies provide researchers with a well-defined population that may be of interest when designing clinical trials. This is particularly useful in the recruitment of a high-risk, traditionally underrepresented populations for non-pharmacological clinical trials where traditional recruitment methods may prolong enrollment periods and extend study budgets.

Household and Living Arrangement Projections at the Subnational Level: An Extended Cohort-Component Approach

PubMed Central

Zeng, Yi; Land, Kenneth C.; Wang, Zhenglian; Gu, Danan

2012-01-01

This article presents the core methodological ideas, empirical assessments, and applications of an extended cohort-component approach (known as the “ProFamy model”) to simultaneously project household composition, living arrangements, and population sizes at the subnational level in the United States. Comparisons of projections from 1990 to 2000 using this approach with census counts in 2000 for each of the 50 states and Washington, DC show that 68.0 %, 17.0 %, 11.2 %, and 3.8 % of the absolute percentage errors are <3.0 %, 3.0 % to 4.99 %, 5.0 % to 9.99 %, and ≥10.0 %, respectively. Another analysis compares average forecast errors between the extended cohort-component approach and the still widely used classic headship-rate method, by projecting number-of-bedrooms–specific housing demands from 1990 to 2000 and then comparing those projections with census counts in 2000 for each of the 50 states and Washington, DC. The results demonstrate that, compared with the extended cohort-component approach, the headship-rate method produces substantially more serious forecast errors because it cannot project households by size while the extended cohort-component approach projects detailed household sizes. We also present illustrative household and living arrangement projections for the five decades from 2000 to 2050, with medium-, small-, and large-family scenarios for each of the 50 states; Washington, DC; six counties of southern California, and the Minneapolis–St. Paul metropolitan area. Among many interesting numerical outcomes of household and living arrangement projections with medium, low, and high bounds, the aging of American households over the next few decades across all states/areas is particularly striking. Finally, the limitations of the present study and potential future lines of research are discussed. PMID:23208782

Establishment of an 11-year cohort of 8733 pediatric patients hospitalized at United States free-standing children's hospitals with de novo acute lymphoblastic leukemia from health care administrative data.

PubMed

Fisher, Brian T; Harris, Tracey; Torp, Kari; Seif, Alix E; Shah, Ami; Huang, Yuan-Shung V; Bailey, L Charles; Kersun, Leslie S; Reilly, Anne F; Rheingold, Susan R; Walker, Dana; Li, Yimei; Aplenc, Richard

2014-01-01

Acute lymphoblastic leukemia (ALL) accounts for almost one quarter of pediatric cancer in the United States. Despite cooperative group therapeutic trials, there remains a paucity of large cohort data on which to conduct epidemiology and comparative effectiveness research studies. We designed a 3-step process utilizing International Classification of Diseases-9 Clinical Modification (ICD-9) discharge diagnoses codes and chemotherapy exposure data contained in the Pediatric Health Information System administrative database to establish a cohort of children with de novo ALL. This process was validated by chart review at 1 of the pediatric centers. An ALL cohort of 8733 patients was identified with a sensitivity of 88% [95% confidence interval (CI), 83%-92%] and a positive predictive value of 93% (95% CI, 89%-96%). The 30-day all cause inpatient case fatality rate using this 3-step process was 0.80% (95% CI, 0.63%-1.01%), which was significantly different than the case fatality rate of 1.40% (95% CI, 1.23%-1.60%) when ICD-9 codes alone were used. This is the first report of assembly and validation of a cohort of de novo ALL patients from a database representative of free-standing children's hospitals across the United States. Our data demonstrate that the use of ICD-9 codes alone to establish cohorts will lead to substantial patient misclassification and result in biased outcome estimates. Systematic methods beyond the use of just ICD-9 codes must be used before analysis to establish accurate cohorts of patients with malignancy. A similar approach should be followed when establishing future cohorts from administrative data.

Estimating health state utility values for comorbid health conditions using SF-6D data.

PubMed

Ara, Roberta; Brazier, John

2011-01-01

When health state utility values for comorbid health conditions are not available, data from cohorts with single conditions are used to estimate scores. The methods used can produce very different results and there is currently no consensus on which is the most appropriate approach. The objective of the current study was to compare the accuracy of five different methods within the same dataset. Data collected during five Welsh Health Surveys were subgrouped by health status. Mean short-form 6 dimension (SF-6D) scores for cohorts with a specific health condition were used to estimate mean SF-6D scores for cohorts with comorbid conditions using the additive, multiplicative, and minimum methods, the adjusted decrement estimator (ADE), and a linear regression model. The mean SF-6D for subgroups with comorbid health conditions ranged from 0.4648 to 0.6068. The linear model produced the most accurate scores for the comorbid health conditions with 88% of values accurate to within the minimum important difference for the SF-6D. The additive and minimum methods underestimated or overestimated the actual SF-6D scores respectively. The multiplicative and ADE methods both underestimated the majority of scores. However, both methods performed better when estimating scores smaller than 0.50. Although the range in actual health state utility values (HSUVs) was relatively small, our data covered the lower end of the index and the majority of previous research has involved actual HSUVs at the upper end of possible ranges. Although the linear model gave the most accurate results in our data, additional research is required to validate our findings. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

The Chinese Children and Families Cohort Study

PubMed Central

Potischman, Nancy; Fang, Liwen; Hao, Ling; Bailey, Regan R.; Berrigan, David; Berry, Robert John; Brodie, Alison; Chao, Ann; Chen, Jing; Dodd, Kevin; Feng, Yajing; Ma, Guansheng; He, Yuna; Fan, Jing; Kimlin, Michael; Kitahara, Cari; Linet, Martha; Li, Zhu; Liu, Ailing; Liu, Yashan; Sampson, Joshua; Su, Joseph; Sun, Jiandong; Tasevska, Natasha; Yang, Lichen; Yang, Ruilan; Zhang, Qian; Wang, Ning; Wang, Linhong; Yu, Wang

2018-01-01

This article reports the study design, methodological issues and early results of a pilot study testing methods for collecting nutrition, physical activity, and ultraviolet (UV) radiation exposure data in a groundbreaking study in China. Epidemiological studies suggest that exposures across the entire life course, including in utero, early childhood, and adolescence, may be important in the etiology of adult cancers and other chronic diseases. The Chinese Children and Families Cohort Study intends to follow-up subjects from the 1993 to 1995 Community Intervention Program of folic acid supplementation for the prevention of neural tube defects. This cohort is unique in that only folic acid exposure during pregnancy varies between groups as other supplements were not available, and there were nutrient deficiencies in the populations. Prior to launching a large-scale follow-up effort, a pilot study was conducted to assess the feasibility of recontacting original study participants to collect extensive diet, physical activity, and UV radiation exposure data in this population. The pilot study included 92 mothers and 184 adolescent children aged 14 to 17 years from 1 urban and 1 rural Community Intervention Program site. Subjects completed a Food Frequency Questionnaire, a 3-day food record, a physical activity questionnaire, a 3-day sun exposure diary together with 3 days of personal UV dosimetry, and 7 days of pedometry measurements and provided blood, saliva, and toenail samples. Grip strength and body composition measurements were taken, and ambient solar UV radiation was monitored in both study sites. While most of the assessments were successful, future studies would likely require different dietary intake instruments. The purpose of this report is to describe the study design and methodological issues emerging from this pilot work relevant for the follow-up of this large birth cohort. PMID:29930434

Personal hair dyes use and risk of glioma: a meta-analysis

PubMed Central

Shao, Chuan; Qi, Zhen-Yu; Hui, Guo-Zhen; Wang, Zhong

2013-01-01

Background and Objective: Use of hair dyes for glioma risk has been investigated in numerous epidemiological studies, but the evidence is inconsistent. Therefore, a meta-analysis was performed to estimate the association between hair dyes use and glioma risk. Methods: We searched PubMed and EMBASE databases without any limitations, covering all papers published by the end of March 8, 2013. Cohort and case-control studies reporting relative risk estimates (RRs) with corresponding 95% confidence intervals (CIs) (or data to calculate them) on this issue were included. Random effects models were used to calculate the pooled RRs and corresponding 95% CIs. Results: Four case-control and two cohort studies were included in this meta-analysis. The summary RRs and 95 % CIs for ever users of any hair dyes were 1.132 (0.887-1.446) for all studies, 1.291 (0.938-1.777) for case-control studies, and 0.903 (0.774-1.054) for cohort studies. In the subgroup analysis by geographic regions and sex, the similar results were detected. No significant associations were also observed among the studies which reported data involving permanent hair dye use and duration of any hair dye use. Conclusion: In summary, the results of our study demonstrated that hair dyes use is not associated with risk of glioma. PMID:24179568

The Zambia Children's KS-HHV8 Study: Rationale, Study Design, and Study Methods

PubMed Central

Minhas, Veenu; Crabtree, Kay L.; Chao, Ann; Wojcicki, Janet M.; Sifuniso, Adrian M.; Nkonde, Catherine; Kankasa, Chipepo; Mitchell, Charles D.; Wood, Charles

2011-01-01

The epidemic of human immunodeficiency virus in Zambia has led to a dramatic rise in the incidence of human herpesvirus-8 (HHV-8)–associated Kaposi's sarcoma in both adults and children. However, there is a paucity of knowledge about the routes of HHV-8 transmission to young children. The Zambia Children's KS-HHV8 Study, a large, prospective cohort study in Lusaka, Zambia, was launched in 2004 to investigate the role of household members as a source of HHV-8 infection in young children and social behaviors that may modify the risk of HHV-8 acquisition. This cohort is distinct from other epidemiologic studies designed to investigate HHV-8 incidence and transmission because it recruited and followed complete households in the urban central African context. Between July 2004 and March 2007, 1,600 households were screened; 368 households comprising 464 children and 1,335 caregivers and household members were enrolled. Follow-up of this population continued for 48 months postrecruitment, affording a unique opportunity to study horizontal transmission of HHV-8 and understand the routes and sources of transmission to young children in Zambia. The authors describe the study rationale, design, execution, and characteristics of this cohort, which provides critical data on the epidemiology and transmission of HHV-8 to young children in Zambia. PMID:21447476

Deconstructing the complexity of substance use among young men who have sex with men (YMSM) by optimizing the role of qualitative strategies in a mixed methods study.

PubMed

Kubicek, Katrina; Weiss, George; Iverson, Ellen F; Kipke, Michele D

2010-04-01

Qualitative data can be a powerful tool in developing interventions for substance use and other HIV-risk behaviors. Mixed methods design offers researchers the ability to obtain data that provides both breadth and depth to their research questions. However, the integration of qualitative data in mixed methods research has been limited. This paper describes the qualitative study design of the Healthy Young Men's Study, a longitudinal mixed method study with an ethnically diverse cohort of young men who have sex with men (YMSM) (N = 526) in Los Angeles. Integral to this discussion is how a mixed methods study can address common challenges such as sampling, representation and integration of both datasets.

Quantitative assessment of invasive mena isoforms (Menacalc) as an independent prognostic marker in breast cancer.

PubMed

Agarwal, Seema; Gertler, Frank B; Balsamo, Michele; Condeelis, John S; Camp, Robert L; Xue, Xiaonan; Lin, Juan; Rohan, Thomas E; Rimm, David L

2012-09-12

Mena, an Ena/VASP protein family member, is a key actin regulatory protein. Mena is up-regulated in breast cancers and promotes invasion and motility of tumor cells. Mena has multiple splice variants, including Mena invasive (MenaINV) and Mena11a, which are expressed in invasive or non-invasive tumor cells, respectively. We developed a multiplex quantitative immunofluorescence (MQIF) approach to assess the fraction of Mena lacking 11a sequence as a method to infer the presence of invasive tumor cells represented as total Mena minus Mena11a (called Menacalc) and determined its association with metastasis in breast cancer. The MQIF method was applied to two independent primary breast cancer cohorts (Cohort 1 with 501 and Cohort 2 with 296 patients) using antibodies against Mena and its isoform, Mena11a. Menacalc was determined for each patient and assessed for association with risk of disease-specific death. Total Mena or Mena11a isoform expression failed to show any statistically significant association with outcome in either cohort. However, assessment of Menacalc showed that relatively high levels of this biomarker is associated with poor outcome in two independent breast cancer cohorts (log rank P = 0.0004 for Cohort 1 and 0.0321 for Cohort 2). Multivariate analysis on combined cohorts revealed that high Menacalc is associated with poor outcome, independent of age, node status, receptor status and tumor size. High Menacalc levels identify a subgroup of breast cancer patients with poor disease-specific survival, suggesting that Menacalc may serve as a biomarker for metastasis.

COVARIATE-ADAPTIVE CLUSTERING OF EXPOSURES FOR AIR POLLUTION EPIDEMIOLOGY COHORTS*

PubMed Central

Keller, Joshua P.; Drton, Mathias; Larson, Timothy; Kaufman, Joel D.; Sandler, Dale P.; Szpiro, Adam A.

2017-01-01

Cohort studies in air pollution epidemiology aim to establish associations between health outcomes and air pollution exposures. Statistical analysis of such associations is complicated by the multivariate nature of the pollutant exposure data as well as the spatial misalignment that arises from the fact that exposure data are collected at regulatory monitoring network locations distinct from cohort locations. We present a novel clustering approach for addressing this challenge. Specifically, we present a method that uses geographic covariate information to cluster multi-pollutant observations and predict cluster membership at cohort locations. Our predictive k-means procedure identifies centers using a mixture model and is followed by multi-class spatial prediction. In simulations, we demonstrate that predictive k-means can reduce misclassification error by over 50% compared to ordinary k-means, with minimal loss in cluster representativeness. The improved prediction accuracy results in large gains of 30% or more in power for detecting effect modification by cluster in a simulated health analysis. In an analysis of the NIEHS Sister Study cohort using predictive k-means, we find that the association between systolic blood pressure (SBP) and long-term fine particulate matter (PM2.5) exposure varies significantly between different clusters of PM2.5 component profiles. Our cluster-based analysis shows that for subjects assigned to a cluster located in the Midwestern U.S., a 10 μg/m3 difference in exposure is associated with 4.37 mmHg (95% CI, 2.38, 6.35) higher SBP. PMID:28572869

Applying Classification Trees to Hospital Administrative Data to Identify Patients with Lower Gastrointestinal Bleeding

PubMed Central

Siddique, Juned; Ruhnke, Gregory W.; Flores, Andrea; Prochaska, Micah T.; Paesch, Elizabeth; Meltzer, David O.; Whelan, Chad T.

2015-01-01

Background Lower gastrointestinal bleeding (LGIB) is a common cause of acute hospitalization. Currently, there is no accepted standard for identifying patients with LGIB in hospital administrative data. The objective of this study was to develop and validate a set of classification algorithms that use hospital administrative data to identify LGIB. Methods Our sample consists of patients admitted between July 1, 2001 and June 30, 2003 (derivation cohort) and July 1, 2003 and June 30, 2005 (validation cohort) to the general medicine inpatient service of the University of Chicago Hospital, a large urban academic medical center. Confirmed cases of LGIB in both cohorts were determined by reviewing the charts of those patients who had at least 1 of 36 principal or secondary International Classification of Diseases, Ninth revision, Clinical Modification (ICD-9-CM) diagnosis codes associated with LGIB. Classification trees were used on the data of the derivation cohort to develop a set of decision rules for identifying patients with LGIB. These rules were then applied to the validation cohort to assess their performance. Results Three classification algorithms were identified and validated: a high specificity rule with 80.1% sensitivity and 95.8% specificity, a rule that balances sensitivity and specificity (87.8% sensitivity, 90.9% specificity), and a high sensitivity rule with 100% sensitivity and 91.0% specificity. Conclusion These classification algorithms can be used in future studies to evaluate resource utilization and assess outcomes associated with LGIB without the use of chart review. PMID:26406318

Pteridine levels and head weights are correlated with age and colony task in the honey bee, Apis mellifera

PubMed Central

Rinkevich, Frank D.; Margotta, Joseph W.; Pittman, Jean M.; Ottea, James A.

2016-01-01

Background. The age of an insect strongly influences many aspects of behavior and reproduction. The interaction of age and behavior is epitomized in the temporal polyethism of honey bees in which young adult bees perform nurse and maintenance duties within the colony, while older bees forage for nectar and pollen. Task transition is dynamic and driven by colony needs. However, an abundance of precocious foragers or overage nurses may have detrimental effects on the colony. Additionally, honey bee age affects insecticide sensitivity. Therefore, determining the age of a set of individual honey bees would be an important measurement of colony health. Pteridines are purine-based pigment molecules found in many insect body parts. Pteridine levels correlate well with age, and wild caught insects may be accurately aged by measuring pteridine levels. The relationship between pteridines and age varies with a number of internal and external factors among many species. Thus far, no studies have investigated the relationship of pteridines with age in honey bees. Methods. We established single-cohort colonies to obtain age-matched nurse and forager bees. Bees of known ages were also sampled from colonies with normal demographics. Nurses and foragers were collected every 3–5 days for up to 42 days. Heads were removed and weighed before pteridines were purified and analyzed using previously established fluorometric methods. Results. Our analysis showed that pteridine levels significantly increased with age in a linear manner in both single cohort colonies and colonies with normal demography. Pteridine levels were higher in foragers than nurses of the same age in bees from single cohort colonies. Head weight significantly increased with age until approximately 28-days of age and then declined for both nurse and forager bees in single cohort colonies. A similar pattern of head weight in bees from colonies with normal demography was observed but head weight was highest in 8-day old nurse bees and there was no relationship of head weight with age of foragers. Discussion. Although the relationship between pteridine levels and age was significant, variation in the data yielded a +4-day range in age estimation. This allows an unambiguous method to determine whether a bee may be a young nurse or old forager in colonies with altered demographics as in the case of single cohort colonies. Pteridine levels in bees do not correlate with age as well as in other insects. However, most studies used insects reared under tightly controlled laboratory conditions, while we used free-living bees. The dynamics of head weight change with age is likely to be due to growth and atrophy of the hypopharyngeal glands. Taken together, these methods represent a useful tool for assessing the age of an insect. Future studies utilizing these methods will provide a more holistic view of colony health. PMID:27413635

Compression or expansion of disability among two birth cohorts of US adults with diabetes during the past 20 years?

PubMed Central

Bardenheier, Barbara H; Lin, Ji; Zhuo, Xiaohui; Ali, Mohammed K; Thompson, Theodore J; Cheng, Yiling J; Gregg, Edward W

2016-01-01

Summary Background The life expectancy of the average American with diabetes has increased, but the level of health and functioning of those extra years are not known. Methods Comparing adults aged 50 to 70 with (n=3,027) and without diabetes (n=9,750), we assessed incident disability, remission from disability, and mortality between population-based Cohort 1 (born 1931-1941, followed 1992 to 2002) and Cohort 2 (born 1942-1947, followed 2002 to 2012), from the Health and Retirement Study. Disability was defined by mobility loss, some difficulty with ≥1 instrumental activities of daily living (IADL), and some difficulty with ≥1 activities of daily living (ADL). Age-specific probabilities representing the two birth cohorts in the U.S. were entered into a five-state Markov model to estimate the number of years of disabled and disability-free life by age 70. Findings Among persons with diabetes, compared with Cohort 1(n=1,071), Cohort 2 (n=300) experienced more disability-free and total years of life, later onset of disability, and fewer disabled years lost. Solutions to the simulations of the Markov models suggest that among 50 year old diabetic men this amounted to a 0.8 to 2.3 year delay in disability across the 3 metrics (mobility p=0.01, IADL p=0.24, ADL p=0.01), while living 0.7 to 1.3 years longer (mobility p<0.0001, IADL p=0.001, ADL p<0.0001); results were similar for women. Parallel improvements in disabled life were gained across cohorts of non-diabetic adults (cohort 1 n=9,218; cohort 2 n=2,727), although non-diabetic adults in both cohort 1 and cohort 2 had significantly more disability-free years (e.g., cohort 1: non-diabetic men from age 50: 17.0 vs diabetic men: 13.0; cohort 2: non-diabetic men from age 50: 17.9 vs diabetic men: 14.8) and fewer life years lost (e.g., cohort 1: non-diabetic men from age 50: 1.2 vs diabetic men: 2.8; cohort 2: non-diabetic men from age 50: 0.6 vs diabetic men: 1.5) than diabetic adults within the two cohorts (p< 0.0001). Interpretation Regardless of diabetes status, adults experienced compression of disability and gains in disability-free life years. Funding None PMID:27298181

Venous Thromboembolism and Cerebrovascular Events in Patients with Giant Cell Arteritis: A Population-Based Retrospective Cohort Study

PubMed Central

Crowson, Cynthia S.; Makol, Ashima; Ytterberg, Steven R.; Saitta, Antonino; Salvarani, Carlo; Matteson, Eric L.; Warrington, Kenneth J.

2016-01-01

Objective To investigate the incidence of venous thromboembolism (VTE) and cerebrovascular events in a community-based incidence cohort of patients with giant cell arteritis (GCA) compared to the general population. Methods A population-based inception cohort of patients with incident GCA between January 1, 1950 and December 31, 2009 in Olmsted County, Minnesota and a cohort of non-GCA subjects from the same population were assembled and followed until December 31, 2013. Confirmed VTE and cerebrovascular events were identified through direct medical record review. Results The study population included 244 patients with GCA with a mean ± SD age at diagnosis of 76.2 ± 8.2 years (79% women) and an average length of follow-up of 10.2 ± 6.8 years. Compared to non-GCA subjects of similar age and sex, patients diagnosed with GCA had a higher incidence (%) of amaurosis fugax (cumulative incidence ± SE: 2.1 ± 0.9 versus 0, respectively; p = 0.014) but similar rates of stroke, transient ischemic attack (TIA), and VTE. Among patients with GCA, neither baseline characteristics nor laboratory parameters at diagnosis reliably predicted risk of VTE or cerebrovascular events. Conclusion In this population-based study, the incidence of VTE, stroke and TIA was similar in patients with GCA compared to non-GCA subjects. PMID:26901431

Social networks and patterns of health risk behaviours over two decades: A multi-cohort study.

PubMed

Kauppi, Maarit; Elovainio, Marko; Stenholm, Sari; Virtanen, Marianna; Aalto, Ville; Koskenvuo, Markku; Kivimäki, Mika; Vahtera, Jussi

2017-08-01

To determine the associations between social network size and subsequent long-term health behaviour patterns, as indicated by alcohol use, smoking, and physical activity. Repeat data from up to six surveys over a 15- or 20-year follow-up were drawn from the Finnish Public Sector study (Raisio-Turku cohort, n=986; Hospital cohort, n=7307), and the Health and Social Support study (n=20,115). Social network size was determined at baseline, and health risk behaviours were assessed using repeated data from baseline and follow-up. We pooled cohort-specific results from repeated-measures log-binomial regression with the generalized estimating equations (GEE) method using fixed-effects meta-analysis. Participants with up to 10 members in their social network at baseline had an unhealthy risk factor profile throughout the follow-up. The pooled relative risks adjusted for age, gender, survey year, chronic conditions and education were 1.15 for heavy alcohol use (95% CI: 1.06-1.24), 1.19 for smoking (95% CI: 1.12-1.27), and 1.25 for low physical activity (95% CI: 1.21-1.29), as compared with those with >20 members in their social network. These associations appeared to be similar in subgroups stratified according to gender, age and education. Social network size predicted persistent behaviour-related health risk patterns up to at least two decades. Copyright © 2017 Elsevier Inc. All rights reserved.

Incidence of schizophrenia among second-generation immigrants in the jerusalem perinatal cohort.

PubMed

Corcoran, Cheryl; Perrin, Mary; Harlap, Susan; Deutsch, Lisa; Fennig, Shmuel; Manor, Orly; Nahon, Daniella; Kimhy, David; Malaspina, Dolores; Susser, Ezra

2009-05-01

Increased incidence of schizophrenia is observed among some immigrant groups in Europe, with the offspring of immigrants, ie "second-generation" immigrants particularly vulnerable. Few contemporary studies have evaluated the risk of schizophrenia among second-generation immigrants in other parts of the world. We studied the incidence of schizophrenia in relation to parental immigrant status in a population-based cohort of 88 829 offspring born in Jerusalem in 1964-1976. Parental countries of birth were obtained from birth certificates and grouped together as (1) Israel, (2) Other West Asia, (3) North Africa, and (4) Europe and industrialized countries. Cox proportional hazards methods were used in adjusting for sex, parents' ages, maternal education, social class, and birth order. Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. Incidence of schizophrenia was not increased among second-generation immigrants in this birth cohort, neither overall nor by specific group. The difference in risk of schizophrenia among second-generation immigrants in Europe and in this Israeli birth cohort suggests that the nature of the immigration experience may be relevant to risk, including reasons for migration, the nature of entry, and subsequent position in the host country for immigrants and their offspring. Minority status may be of importance as, in later studies, immigrants to Israel from Ethiopia had increased risk of schizophrenia.

Gynecological malignancy risk in colorectal cancer survivors: A population-based cohort study.

PubMed

Chang, Wei-Chun; Muo, Chih-Hsin; Liang, Ji-An; Sung, Fung-Chang; Kao, Chia-Hung

2015-10-01

This study was carried out to assess the risk of gynecological malignancy in colorectal cancer survivors using a population-based retrospective cohort study. Using the National Health Insurance Research Database (NHIRD) of Taiwan, we identified 37,176 patients with colorectal cancer diagnosed in 1998-2009, aged 20 years and above, without other cancer history. We also randomly selected 148,700 women without any cancer in the comparison cohort, frequency matched by age and diagnosis date. Incidences and hazards of breast, cervix, endometrial and ovarian cancers were evaluated by 201l. The overall incidence of the 4 types of gynecological cancer was 39.0% higher in colorectal cancer patients than in comparisons (2.99 vs. 2.14 per 1000 person-years) with an adjusted hazard ratio (HR) of 1.46 (95% confidence interval (CI) = 1.31-1.62). Breast cancer accounted for most subsequent cancer. The multivariable Cox method measured HR was the highest for endometrial cancer (3.40, 95% CI = 2.59-4.47) for the colorectal cohort relative to comparisons, followed by ovarian cancer and breast cancer, except cervix cancer. The risk of gynecological malignancies was apparently elevated for colorectal cancer survivors <50 years of age. Follow-up measures are suggested for women with colorectal cancer for early detection and prevention of the subsequent gynecological malignancy. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Study of Group Dynamics in Educational Leadership Cohort and Non-Cohort Groups

ERIC Educational Resources Information Center

Greenlee, Bobbie J.; Karanxha, Zorka

2010-01-01

The purpose of this study was to examine group dynamics of educational leadership students in cohorts and make comparisons with the group dynamics characteristics of non-cohort students. Cohorts have emerged as dynamic and adaptive entities with attendant group dynamic processes that shape collective learning and action. Cohort (n=42) and…

Methods to Develop an Electronic Medical Record Phenotype Algorithm to Compare the Risk of Coronary Artery Disease across 3 Chronic Disease Cohorts.

PubMed

Liao, Katherine P; Ananthakrishnan, Ashwin N; Kumar, Vishesh; Xia, Zongqi; Cagan, Andrew; Gainer, Vivian S; Goryachev, Sergey; Chen, Pei; Savova, Guergana K; Agniel, Denis; Churchill, Susanne; Lee, Jaeyoung; Murphy, Shawn N; Plenge, Robert M; Szolovits, Peter; Kohane, Isaac; Shaw, Stanley Y; Karlson, Elizabeth W; Cai, Tianxi

2015-01-01

Typically, algorithms to classify phenotypes using electronic medical record (EMR) data were developed to perform well in a specific patient population. There is increasing interest in analyses which can allow study of a specific outcome across different diseases. Such a study in the EMR would require an algorithm that can be applied across different patient populations. Our objectives were: (1) to develop an algorithm that would enable the study of coronary artery disease (CAD) across diverse patient populations; (2) to study the impact of adding narrative data extracted using natural language processing (NLP) in the algorithm. Additionally, we demonstrate how to implement CAD algorithm to compare risk across 3 chronic diseases in a preliminary study. We studied 3 established EMR based patient cohorts: diabetes mellitus (DM, n = 65,099), inflammatory bowel disease (IBD, n = 10,974), and rheumatoid arthritis (RA, n = 4,453) from two large academic centers. We developed a CAD algorithm using NLP in addition to structured data (e.g. ICD9 codes) in the RA cohort and validated it in the DM and IBD cohorts. The CAD algorithm using NLP in addition to structured data achieved specificity >95% with a positive predictive value (PPV) 90% in the training (RA) and validation sets (IBD and DM). The addition of NLP data improved the sensitivity for all cohorts, classifying an additional 17% of CAD subjects in IBD and 10% in DM while maintaining PPV of 90%. The algorithm classified 16,488 DM (26.1%), 457 IBD (4.2%), and 245 RA (5.0%) with CAD. In a cross-sectional analysis, CAD risk was 63% lower in RA and 68% lower in IBD compared to DM (p<0.0001) after adjusting for traditional cardiovascular risk factors. We developed and validated a CAD algorithm that performed well across diverse patient populations. The addition of NLP into the CAD algorithm improved the sensitivity of the algorithm, particularly in cohorts where the prevalence of CAD was low. Preliminary data suggest that CAD risk was significantly lower in RA and IBD compared to DM.

Associations between Aspirin and other non-steroidal anti-inflammatory drugs and aortic valve or coronary artery calcification: The Multi-Ethnic Study of Atherosclerosis and the Heinz Nixdorf Recall Study

PubMed Central

Delaney, Joseph A; Lehmann, Nils; Jöckel, Karl-Heinz; Elmariah, Sammy; Psaty, Bruce M; Mahabadi, Amir; Budoff, Matt; Kronmal, Richard A; Nasir, Khurram; O’Brien, Kevin D.; Möhlenkamp, Stefan; Moebus, Susanne; Dragano, Nico; Winterstein, Almut; Erbel, Raimund; Kälsch, Hagen

2013-01-01

Background The association between non-steroidal anti-inflammatory drugs (NSAIDs) and the incidence of valvular and arterial calcification is not well established despite known associations between these drugs and cardiovascular events. Objective To compare the association between the baseline use of aspirin with other NSAID class medications with the incidence and prevalence of aortic valve calcification (AVC) and coronary artery calcium (CAC). Methods The relationship of NSAID use to AVC and CAC detected by computed tomography was assessed in 6,814 participants within the Multi-Ethnic Study of Atherosclerosis (MESA) using regression modeling. Results were adjusted for age, sex, ethnicity, study site, anti-hypertensive medication use, education, income, health insurance status, diabetes, smoking, exercise, body mass index, blood pressure, serum lipids, inflammatory markers, fasting glucose, statin medication use, and a simple diet score. Medication use was assessed by medication inventory at baseline which includes the use of non-prescription NSAIDs. MESA collects information on both incident and prevalent calcification. The 4,814 participants of the Heinz Nixdorf Recall (HNR) Study, a German prospective cohort study with similar measures of calcification, were included in this analysis to enable replication. Results Mean age of the MESA participants was 62 years (51% female). After adjustment for possible confounding factors, a possible association between aspirin use and incident AVC (Relative Risk(RR): 1.60; 95%Confidence Interval (CI): 1.19–2.15) did not replicate in the HNR cohort (RR: 1.06; 95%CI: 0.87–1.28). There was no significant association between aspirin use and incident CAC in the MESA cohort (RR 1.08; 95%CI: 0.91–1.29) or in the HNR cohort (RR 1.24; 95%CI: 0.87–1.77). Non-aspirin NSAID use was not associated with either AVC or CAC in either cohort. There were no associations between regular cardiac dose aspirin and incident calcification in either cohort. Conclusion Baseline NSAID use, as assessed by medication inventory, appears to have no protective effect regarding the onset of calcification in either coronary arteries or aortic valves. PMID:23880181

Comparison of cohort smoking intensities in Denmark and the Netherlands.

PubMed Central

Barendregt, Jan J.; Looman, Caspar W. N.; Brønnum-Hansen, Henrik

2002-01-01

OBJECTIVE: To assess the usefulness of the general framework of the smoking epidemic. METHODS: We use lung cancer mortality as an indicator for smoking intensity and employ an age-cohort model to accommodate the long-lasting and cumulative effects. RESULTS: Dutch males have higher risks than Danish males, but the risks for the younger cohorts have been declining faster in the Netherlands than in Denmark. Danish women have about twice the risk of Dutch women, and in both countries the risks for the younger cohorts are increasing. The smoking epidemic began at about the same time in Denmark and the Netherlands. Dutch males, however, seem to have smoked more but to have given up smoking more quickly than Danish males. Danish females were quicker to take up smoking than Dutch females. CONCLUSIONS: Within the general framework of the smoking epidemic, differences in timing and levels can produce large differences between countries. For the purposes of assessing smoking-related risks, including projections, the smoking epidemic framework therefore has to be tailored to each study population. PMID:11884970

Regional cyst concentration as a prognostic biomarker for polycystic kidney disease

NASA Astrophysics Data System (ADS)

Warner, Joshua D.; Irazabal, Maria V.; Torres, Vicente E.; King, Bernard F.; Erickson, Bradley J.

2014-03-01

Polycystic kidney disease (PKD) is a major cause of renal failure. Despite recent advances in understanding the biochemistry and genetics of PKD, the functional mechanisms underpinning the declines in renal function observed in the disorder are not well established. No studies investigating the distribution of cysts within polycystic kidneys exist. This work introduces regional cyst concentration as a new biomarker for evaluation of patients suffering from PKD. We derive a method to define central and peripheral regions of the kidney, approximating the anatomical division between cortex and medulla, and apply it to two cohorts of ten patients with early/mild or late/severe disease. Our results from the late/severe cohort show peripheral cyst concentration correlates with the current standard PKD biomarker, total kidney volume (TKV), signi cantly better than central cyst concentration (p < 0.05). We also find that cyst concentration was globally increased in the late/severe cohort (p << 0.01) compared to the early/mild cohort, for both central and peripheral regions. These findings show cysts in PKD are not distributed homogeneously throughout the renal tissues.

China’s marriage squeeze: A decomposition into age and sex structure

PubMed Central

LI, Xiaomin; LI, Shuzhuo; FELDMAN, Marcus W.

2016-01-01

Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China’s male marriage squeeze. In this paper we develop an index we call “spousal sex ratio” (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China’s marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market. PMID:27242390

China's marriage squeeze: A decomposition into age and sex structure.

PubMed

Jiang, Quanbao; Li, Xiaomin; Li, Shuzhuo; Feldman, Marcus W

2016-06-01

Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China's male marriage squeeze. In this paper we develop an index we call "spousal sex ratio" (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China's marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market.

Life and Living in Advanced Age: A Cohort Study in New Zealand -Te Puāwaitanga o Nga Tapuwae Kia Ora Tonu, LiLACS NZ: Study protocol

PubMed Central

2012-01-01

Background The number of people of advanced age (85 years and older) is increasing and health systems may be challenged by increasing health-related needs. Recent overseas evidence suggests relatively high levels of wellbeing in this group, however little is known about people of advanced age, particularly the indigenous Māori, in Aotearoa, New Zealand. This paper outlines the methods of the study Life and Living in Advanced Age: A Cohort Study in New Zealand. The study aimed to establish predictors of successful advanced ageing and understand the relative importance of health, frailty, cultural, social & economic factors to successful ageing for Māori and non-Māori in New Zealand. Methods/design A total population cohort study of those of advanced age. Two cohorts of equal size, Māori aged 80–90 and non-Māori aged 85, oversampling to enable sufficient power, were enrolled. A defined geographic region, living in the Bay of Plenty and Lakes District Health Board areas of New Zealand, defined the sampling frame. Rūnanga (Māori tribal organisations) and Primary Health Organisations were subcontracted to recruit on behalf of the University. Measures - a comprehensive interview schedule was piloted and administered by a trained interviewer using standardised techniques. Socio-demographic and personal history included tribal affiliation for Māori and participation in cultural practices; physical and psychological health status used standardised validated research tools; health behaviours included smoking, alcohol use and nutrition risk; and environmental data included local amenities, type of housing and neighbourhood. Social network structures and social support exchanges are recorded. Measures of physical function; gait speed, leg strength and balance, were completed. Everyday interests and activities, views on ageing and financial interests complete the interview. A physical assessment by a trained nurse included electrocardiograph, blood pressure, hearing and vision, anthropometric measures, respiratory function testing and blood samples. Discussion A longitudinal study of people of advanced age is underway in New Zealand. The health status of a population based sample of older people will be established and predictors of successful ageing determined. PMID:22747503

Active aging - resilience and external support as modifiers of the disablement outcome: AGNES cohort study protocol.

PubMed

Rantanen, Taina; Saajanaho, Milla; Karavirta, Laura; Siltanen, Sini; Rantakokko, Merja; Viljanen, Anne; Rantalainen, Timo; Pynnönen, Katja; Karvonen, Anu; Lisko, Inna; Palmberg, Lotta; Eronen, Johanna; Palonen, Eeva-Maija; Hinrichs, Timo; Kauppinen, Markku; Kokko, Katja; Portegijs, Erja

2018-05-02

Population aging increases the need for knowledge on positive aspects of aging, and contributions of older people to their own wellbeing and that of others. We defined active aging as an individual's striving for elements of wellbeing with activities as per their goals, abilities and opportunities. This study examines associations of health, health behaviors, health literacy and functional abilities, environmental and social support with active aging and wellbeing. We will develop and validate assessment methods for physical activity and physical resilience suitable for research on older people, and examine their associations with active aging and wellbeing. We will examine cohort effects on functional phenotypes underlying active aging and disability. For this population-based study, we plan to recruit 1000 participants aged 75, 80 or 85 years living in central Finland, by drawing personal details from the population register. Participants are interviewed on active aging, wellbeing, disability, environmental and social support, mobility, health behavior and health literacy. Physical activity and heart rate are monitored for 7 days with wearable sensors. Functional tests include hearing, vision, muscle strength, reaction time, exercise tolerance, mobility, and cognitive performance. Clinical examination by a nurse and physician includes an electrocardiogram, tests of blood pressure, orthostatic regulation, arterial stiffness, and lung function, as well as a review of chronic and acute conditions and prescribed medications. C-reactive protein, small blood count, cholesterol and vitamin D are analyzed from blood samples. Associations of factors potentially underlying active aging and wellbeing will be studied using multivariate methods. Cohort effects will be studied by comparing test results of physical and cognitive functioning with results of a cohort examined in 1989-90. The current study will renew research on positive gerontology through the novel approach to active aging and by suggesting new biomarkers of resilience and active aging. Therefore, high interdisciplinary impact is expected. This cross-sectional study will not provide knowledge on temporal order of events or causality, but an innovative cross-sectional dataset provides opportunities for emergence of novel creative hypotheses and theories.