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.

[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.

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.

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.

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…

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.

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

Improving Evaluation of Dental Hygiene Students' Cultural Competence with a Mixed-Methods Approach.

PubMed

Flynn, Priscilla; Sarkarati, Nassim

2018-02-01

Most dental hygiene educational programs include cultural competence education, but may not evaluate student outcomes. The aim of this study was to design and implement a mixed-methods evaluation to measure dental hygiene students' progression toward cultural competence. Two cohorts consisting of consecutive classes in one U.S. dental hygiene program participated in the study. A total of 47 dental hygiene students (100% response rate) completed self-assessments to measure their attitudes and knowledge at three time points between 2014 and 2016. Mean scores were calculated for three domains: Physical Environment, Communication, and Values. Qualitative analysis of the students' cultural diversity papers was also conducted to further evaluate students' knowledge and skills. Bennett's five-level conceptual framework was used to code phrases or sentences to place students in the general categories of ethnocentric or ethno-relative. The quantitative and qualitative results yielded different outcomes for Cohort 1, but not for Cohort 2. The Cohort 1 students assessed themselves statistically significantly lower over time in one of the three measured domains. However, the Cohort 2 students assessed themselves as statistically significantly more culturally competent in all three domains. Qualitative results placed 72% of Cohort 1 students and 83% of Cohort 2 students in the more desirable ethno-relative category. Since quantitative methods consisting of student self-assessments may not adequately measure students' cultural competence, adding qualitative methods to measure skills specific to patient care in this study added a robust dimension to evaluating this complex dental hygiene student competence.

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.

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.

Selection of the initial design for the two-stage continual reassessment method.

PubMed

Jia, Xiaoyu; Ivanova, Anastasia; Lee, Shing M

2017-01-01

In the two-stage continual reassessment method (CRM), model-based dose escalation is preceded by a pre-specified escalating sequence starting from the lowest dose level. This is appealing to clinicians because it allows a sufficient number of patients to be assigned to each of the lower dose levels before escalating to higher dose levels. While a theoretical framework to build the two-stage CRM has been proposed, the selection of the initial dose-escalating sequence, generally referred to as the initial design, remains arbitrary, either by specifying cohorts of three patients or by trial and error through extensive simulations. Motivated by a currently ongoing oncology dose-finding study for which clinicians explicitly stated their desire to assign at least one patient to each of the lower dose levels, we proposed a systematic approach for selecting the initial design for the two-stage CRM. The initial design obtained using the proposed algorithm yields better operating characteristics compared to using a cohort of three initial design with a calibrated CRM. The proposed algorithm simplifies the selection of initial design for the two-stage CRM. Moreover, initial designs to be used as reference for planning a two-stage CRM are provided.

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

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.

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

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.

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...

Epidemiological designs for vaccine safety assessment: methods and pitfalls.

PubMed

Andrews, Nick

2012-09-01

Three commonly used designs for vaccine safety assessment post licensure are cohort, case-control and self-controlled case series. These methods are often used with routine health databases and immunisation registries. This paper considers the issues that may arise when designing an epidemiological study, such as understanding the vaccine safety question, case definition and finding, limitations of data sources, uncontrolled confounding, and pitfalls that apply to the individual designs. The example of MMR and autism, where all three designs have been used, is presented to help consider these issues. Copyright © 2011 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Evaluating performance of risk identification methods through a large-scale simulation of observational data.

PubMed

Ryan, Patrick B; Schuemie, Martijn J

2013-10-01

There has been only limited evaluation of statistical methods for identifying safety risks of drug exposure in observational healthcare data. Simulations can support empirical evaluation, but have not been shown to adequately model the real-world phenomena that challenge observational analyses. To design and evaluate a probabilistic framework (OSIM2) for generating simulated observational healthcare data, and to use this data for evaluating the performance of methods in identifying associations between drug exposure and health outcomes of interest. Seven observational designs, including case-control, cohort, self-controlled case series, and self-controlled cohort design were applied to 399 drug-outcome scenarios in 6 simulated datasets with no effect and injected relative risks of 1.25, 1.5, 2, 4, and 10, respectively. Longitudinal data for 10 million simulated patients were generated using a model derived from an administrative claims database, with associated demographics, periods of drug exposure derived from pharmacy dispensings, and medical conditions derived from diagnoses on medical claims. Simulation validation was performed through descriptive comparison with real source data. Method performance was evaluated using Area Under ROC Curve (AUC), bias, and mean squared error. OSIM2 replicates prevalence and types of confounding observed in real claims data. When simulated data are injected with relative risks (RR) ≥ 2, all designs have good predictive accuracy (AUC > 0.90), but when RR < 2, no methods achieve 100 % predictions. Each method exhibits a different bias profile, which changes with the effect size. OSIM2 can support methodological research. Results from simulation suggest method operating characteristics are far from nominal properties.

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

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

Using Team-based Learning to Teach a Hybrid Pharmacokinetics Course Online and in Class.

PubMed

Franklin, Ann Snyder; Markowsky, Susan; De Leo, Justin; Normann, Sven; Black, Erik

2016-12-25

Objective. To compare the effectiveness of face-to-face and online team-based learning (TBL) to teach phenytoin pharmacokinetics. Design. A TBL format was used to teach an online cohort of 222 pharmacy students and two face-to-face cohorts (Tampa and Las Vegas) of pharmacy students. Students in all cohorts completed individual and team readiness tests (iRATs and tRATs), and a self-assessment survey to determine teamwork and content understanding. Knowledge retention questions also were added to the final examination. Assessment. Mean scores on iRATs were: 54% for the Tampa group; 72% for the Las Vegas group; and 58% for the online. Mean tRAT scores were 78.5% for the Tampa cohort and 82.2% for the Las Vegas cohort, compared to 89.5% for the online cohort. The mean tRAT scores for the online cohorts were significantly higher than those of the face-to-face cohorts. Data from the teamwork survey provided evidence of positive interactions among teams for all cohorts. Conclusion. Team-based learning can be an effective method for teaching applied pharmacokinetics in both face-to-face and online classes.

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.

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

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

Lestini, Giulia; Dumont, Cyrielle; Mentré, France

2015-10-01

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. 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*. Estimation results of two-stage ADs and ξ * were close and much better than those obtained with ξ 0. 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. 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.

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

"Do I really want to do this?" Longitudinal cohort study participants' perspectives on postal survey design: a qualitative study

PubMed Central

2011-01-01

Background Randomised controlled trials have investigated aspects of postal survey design yet cannot elaborate on reasons behind participants' decision making and survey behaviour. This paper reports participants' perspectives of the design of, and participation in, a longitudinal postal cohort survey. It describes strengths and weaknesses in study design from the perspectives of study participants and aims to contribute to the: 1) design of future cohort surveys and questionnaires generally and, 2) design of cohort surveys for people with musculoskeletal disorders (MSDs) specifically. Methods In-depth interviews explored the design of postal surveys previously completed by participants. Interviews used open ended questioning with a topic guide for prompts if areas of interest were not covered spontaneously. Thematic data analysis was undertaken based on the framework method. A second researcher verified all coding. Results Data from fourteen interviews were analysed within three main themes; participation, survey design and survey content. One of the main findings was the importance of clear communication aimed at the correct audience both when inviting potential participants to take part and within the survey itself. Providing enough information about the study, having a topic of interest and an explanation of likely benefits of the study were important when inviting people to participate. The neutrality of the survey and origination from a reputable source were both important; as was an explanation about why information was being collected within the survey itself. Study findings included participants' impressions when invited to take part, why they participated, the acceptability of follow-up of non-responders and why participants completed the follow-up postal survey. Also discussed were participants' first impression of the survey, its length, presentation and participants' views about specific questions within the survey. Conclusions Ideas generated in this study provide an insight into participants' decision making and survey behaviour and may enhance the acceptability of future surveys to potential participants. As well as clear communication, participants valued incentives and survey questions that were relevant to them. However, opinions varied as to the preferred format for responses with some advising more opportunity for open-ended feedback. We also found that some standard format questions can raise quandaries for individual participants. PMID:21269515

Utilizing harmonization and common surveillance methods to consolidate 4 cohorts: the Western Alaska Tribal Collaborative for Health (WATCH) study

PubMed Central

Koller, Kathryn R.; Wolfe, Abbie W.; Metzger, Jesse S.; Austin, Melissa A.; Hopkins, Scarlett E.; Kaufmann, Cristiane; Jolly, Stacey E.; Ebbesson, Sven O.E.; Umans, Jason G.; Howard, Barbara V.; Boyer, Bert B.

2013-01-01

Background According to health status reports, chronic disease prevalence appears to be rising in western Alaska Native (AN) people, and accurate population-based data are needed. Four cohort studies of western AN people were conducted in the Norton Sound and Yukon-Kuskokwim regions, but none have been large enough to allow reliable estimates of rates of chronic diseases and evaluate their risk factors. Objective In this article, the methods used to combine 4 major cohort studies of rural western AN people are described and the benefits and challenges encountered in combining data and standardizing surveillance methods for these studies are discussed. Design Tribal permission was obtained for each cohort study and the consolidated study. Data from baseline exams were directly combined or harmonized into new variables. Common surveillance methods were developed and implemented to identify incidence and risk factors for cardiovascular disease (CVD) events and type 2 diabetes. Results A cohort of 4,569 western AN participants (2,116 men and 2,453 women), aged 18–95 years, was established to study CVD and diabetes prevalence. Prospective surveillance data over an average 6.7-year follow-up can now be used to study CVD and diabetes incidence and associated risk factors in a subset of 2,754 western AN participants (1,218 men and 1,536 women) who consented to initial surveillance. Conclusions The combined cohort provides statistical power to examine incidence rates and risk factors for CVD and diabetes and allows for analyses by geographic region. The data can be used to develop intervention programmes in these populations and others. PMID:23671836

Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

PubMed Central

2013-01-01

Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts) project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second hand tobacco smoke (SHS), persistent organic pollutants (POPs), noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts), occupational exposures (N=33), outdoor air pollution, and allergens and microbial agents (N=27). Exposure modeling is increasingly used for long-term air pollution exposure assessment; biomonitoring is used for assessment of exposure to metals, POPs and other chemicals; and environmental monitoring for house dust mite exposure assessment. Collaborative analyses with data from several birth cohorts have already been performed successfully for outdoor air pollution, water contamination, allergens, biological contaminants, molds, POPs and SHS. Key success factors for collaborative analyses are common definitions of main exposure and health variables. Our review emphasizes that such common definitions need ideally be arrived at in the study design phase. However, careful comparison of methods used in existing studies also offers excellent opportunities for collaborative analyses. Investigators can use this review to evaluate the potential for future collaborative analyses with respect to data availability and methods used in the different cohorts and to identify potential partners for a specific research question. PMID:23343014

Legal Outcomes of Sexually Abused Children Evaluated at the Philippine General Hospital Child Protection Unit

ERIC Educational Resources Information Center

Sugue-Castillo, Mariella

2009-01-01

Objectives: To describe the legal outcomes and factors associated with case reaching court and conviction for sexual abuse of children seen at the Philippine General Hospital Child Protection Unit (PGH-CPU) from 1997 to 2000. Methods: Mixed transdisciplinary research design combined longitudinal cohort with qualitative methods. Data were obtained…

Using Predictive Evaluation to Design, Evaluate, and Improve Training for Polio Volunteers

PubMed Central

Traicoff, Denise A.; Basarab, Dave; Ehrhardt, Derek T.; Brown, Sandi; Celaya, Martin; Jarvis, Dennis; Howze, Elizabeth H.

2018-01-01

Background Predictive Evaluation (PE) uses a four-step process to predict results then designs and evaluates a training intervention accordingly. In 2012, the Sustainable Management Development Program (SMDP) at the Centers for Disease Control and Prevention used PE to train Stop Transmission of Polio (STOP) program volunteers. Methods Stakeholders defined specific beliefs and practices that volunteers should demonstrate. These predictions and adult learning practices were used to design a curriculum to train four cohorts. At the end of each workshop, volunteers completed a beliefs survey and wrote goals for intended actions. The goals were analyzed for acceptability based on four PE criteria. The percentage of acceptable goals and the beliefs survey results were used to define the quality of the workshop. A postassignment adoption evaluation was conducted for two cohorts, using an online survey and telephone or in-person structured interviews. The results were compared with the end of workshop findings. Results The percentage of acceptable goals across the four cohorts ranged from 49% to 85%. In the adoption evaluation of two cohorts, 88% and 94% of respondents reported achieving or making significant progress toward their goal. A comparison of beliefs survey responses across the four cohorts indicated consistencies in beliefs that aligned with stakeholders’ predictions. Conclusions Goal statements that participants write at the end of a workshop provide data to evaluate training quality. Beliefs surveys surface attitudes that could help or hinder workplace performance. The PE approach provides an innovative framework for health worker training and evaluation that emphasizes performance. PMID:29457126

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.

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.

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

Estimating effect of environmental contaminants on women's subfecundity for the MoBa study data with an outcome-dependent sampling scheme

PubMed Central

Ding, Jieli; Zhou, Haibo; Liu, Yanyan; Cai, Jianwen; Longnecker, Matthew P.

2014-01-01

Motivated by the need from our on-going environmental study in the Norwegian Mother and Child Cohort (MoBa) study, we consider an outcome-dependent sampling (ODS) scheme for failure-time data with censoring. Like the case-cohort design, the ODS design enriches the observed sample by selectively including certain failure subjects. We present an estimated maximum semiparametric empirical likelihood estimation (EMSELE) under the proportional hazards model framework. The asymptotic properties of the proposed estimator were derived. Simulation studies were conducted to evaluate the small-sample performance of our proposed method. Our analyses show that the proposed estimator and design is more efficient than the current default approach and other competing approaches. Applying the proposed approach with the data set from the MoBa study, we found a significant effect of an environmental contaminant on fecundability. PMID:24812419

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

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.

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.

The Misconception of Case-Control Studies in the Plastic Surgery Literature: A Literature Audit.

PubMed

Hatchell, Alexandra C; Farrokhyar, Forough; Choi, Matthew

2017-06-01

Case-control study designs are commonly used. However, many published case-control studies are not true case-controls and are in fact mislabeled. The purpose of this study was to identify all case-control studies published in the top three plastic surgery journals over the past 10 years, assess which were truly case-control studies, clarify the actual design of the articles, and address common misconceptions. MEDLINE, Embase, and Web of Science databases were searched for case-control studies in the three highest-impact factor plastic surgery journals (2005 to 2015). Two independent reviewers screened the resulting titles, abstracts, and methods, if applicable, to identify articles labeled as case-control studies. These articles were appraised and classified as true case-control studies or non-case-control studies. The authors found 28 articles labeled as case-control studies. However, only six of these articles (21 percent) were truly case-control designs. Of the 22 incorrectly labeled studies, one (5 percent) was a randomized controlled trial, three (14 percent) were nonrandomized trials, two (9 percent) were prospective comparative cohort designs, 14 (64 percent) were retrospective comparative cohort designs, and two (9 percent) were cross-sectional designs. The mislabeling was worse in recent years, despite increases in evidence-based medicine awareness. The majority of published case-control studies are not in fact case-control studies. This misunderstanding is worsening with time. Most of these studies are actually comparative cohort designs. However, some studies are truly clinical trials and thus a higher level of evidence than originally proposed.

How Are the Costs of Care for Medical Falls Distributed? The Costs of Medical Falls by Component of Cost, Timing, and Injury Severity

ERIC Educational Resources Information Center

Bohl, Alex A.; Phelan, Elizabeth A.; Fishman, Paul A.; Harris, Jeffrey R.

2012-01-01

Purpose of the Study: To examine the components of cost that drive increased total costs after a medical fall over time, stratified by injury severity. Design and Methods: We used 2004-2007 cost and utilization data for persons enrolled in an integrated care delivery system. We used a longitudinal cohort study design, where each individual…

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

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.

Outcome-Dependent Sampling with Interval-Censored Failure Time Data

PubMed Central

Zhou, Qingning; Cai, Jianwen; Zhou, Haibo

2017-01-01

Summary Epidemiologic studies and disease prevention trials often seek to relate an exposure variable to a failure time that suffers from interval-censoring. When the failure rate is low and the time intervals are wide, a large cohort is often required so as to yield reliable precision on the exposure-failure-time relationship. However, large cohort studies with simple random sampling could be prohibitive for investigators with a limited budget, especially when the exposure variables are expensive to obtain. Alternative cost-effective sampling designs and inference procedures are therefore desirable. We propose an outcome-dependent sampling (ODS) design with interval-censored failure time data, where we enrich the observed sample by selectively including certain more informative failure subjects. We develop a novel sieve semiparametric maximum empirical likelihood approach for fitting the proportional hazards model to data from the proposed interval-censoring ODS design. This approach employs the empirical likelihood and sieve methods to deal with the infinite-dimensional nuisance parameters, which greatly reduces the dimensionality of the estimation problem and eases the computation difficulty. The consistency and asymptotic normality of the resulting regression parameter estimator are established. The results from our extensive simulation study show that the proposed design and method works well for practical situations and is more efficient than the alternative designs and competing approaches. An example from the Atherosclerosis Risk in Communities (ARIC) study is provided for illustration. PMID:28771664

Overview of clinical research design.

PubMed

Hartung, Daniel M; Touchette, Daniel

2009-02-15

Basic concepts and terminology of clinical research design are presented for new clinical investigators. Clinical research, research involving human subjects, can be described as either observational or experimental. The findings of all clinical research can be threatened by issues of bias and confounding. Biases are systematic errors in how study subjects are selected or measured, which result in false inferences. Confounding is a distortion in findings that is attributable to mixing variable effects. Uncontrolled observation research is generally more prone to bias and confounding than experimental research. Observational research includes designs such as the cohort study, case-control study, and cross-sectional study, while experimental research typically involves a randomized controlled trial (RCT). The cohort study, which includes the RCT, defines subject allocation on the basis of exposure interest (e.g., drug, disease-management program) and follows the patients to assess the outcomes. The case-control study uses the primary outcome of interest (e.g., adverse event) to define subject allocation, and different exposures are assessed in a retrospective manner. Cross-sectional research evaluates both exposure and outcome concurrently. Each of these design methods possesses different strengths and weaknesses in answering research questions, as well as underlying many study subtypes. While experimental research is the strongest method for establishing causality, it can be difficult to accomplish under many scenarios. Observational clinical research offers many design alternatives that may be appropriate if planned and executed carefully.

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.

Signatures of tumour immunity distinguish Asian and non-Asian gastric adenocarcinomas

PubMed Central

Lin, Suling J; Gagnon-Bartsch, Johann A; Tan, Iain Beehuat; Earle, Sophie; Ruff, Louise; Pettinger, Katherine; Ylstra, Bauke; van Grieken, Nicole; Rha, Sun Young; Chung, Hyun Cheol; Lee, Ju-Seog; Cheong, Jae Ho; Noh, Sung Hoon; Aoyama, Toru; Miyagi, Yohei; Tsuburaya, Akira; Yoshikawa, Takaki; Ajani, Jaffer A; Boussioutas, Alex; Yeoh, Khay Guan; Yong, Wei Peng; So, Jimmy; Lee, Jeeyun; Kang, Won Ki; Kim, Sung; Kameda, Yoichi; Arai, Tomio; zur Hausen, Axel; Speed, Terence P; Grabsch, Heike I; Tan, Patrick

2015-01-01

Objective Differences in gastric cancer (GC) clinical outcomes between patients in Asian and non-Asian countries has been historically attributed to variability in clinical management. However, recent international Phase III trials suggest that even with standardised treatments, GC outcomes differ by geography. Here, we investigated gene expression differences between Asian and non-Asian GCs, and if these molecular differences might influence clinical outcome. Design We compared gene expression profiles of 1016 GCs from six Asian and three non-Asian GC cohorts, using a two-stage meta-analysis design and a novel biostatistical method (RUV-4) to adjust for technical variation between cohorts. We further validated our findings by computerised immunohistochemical analysis on two independent tissue microarray (TMA) cohorts from Asian and non-Asian localities (n=665). Results Gene signatures differentially expressed between Asians and non-Asian GCs were related to immune function and inflammation. Non-Asian GCs were significantly enriched in signatures related to T-cell biology, including CTLA-4 signalling. Similarly, in the TMA cohorts, non-Asian GCs showed significantly higher expression of T-cell markers (CD3, CD45R0, CD8) and lower expression of the immunosuppressive T-regulatory cell marker FOXP3 compared to Asian GCs (p<0.05). Inflammatory cell markers CD66b and CD68 also exhibited significant cohort differences (p<0.05). Exploratory analyses revealed a significant relationship between tumour immunity factors, geographic locality-specific prognosis, and postchemotherapy outcomes. Conclusions Analyses of >1600 GCs suggest that Asian and non-Asian GCs exhibit distinct tumour immunity signatures related to T-cell function. These differences may influence geographical differences in clinical outcome, and the design of future trials particularly in immuno-oncology. PMID:25385008

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

Systematic review finds major deficiencies in sample size methodology and reporting for stepped-wedge cluster randomised trials

PubMed Central

Martin, James; Taljaard, Monica; Girling, Alan; Hemming, Karla

2016-01-01

Background Stepped-wedge cluster randomised trials (SW-CRT) are increasingly being used in health policy and services research, but unless they are conducted and reported to the highest methodological standards, they are unlikely to be useful to decision-makers. Sample size calculations for these designs require allowance for clustering, time effects and repeated measures. Methods We carried out a methodological review of SW-CRTs up to October 2014. We assessed adherence to reporting each of the 9 sample size calculation items recommended in the 2012 extension of the CONSORT statement to cluster trials. Results We identified 32 completed trials and 28 independent protocols published between 1987 and 2014. Of these, 45 (75%) reported a sample size calculation, with a median of 5.0 (IQR 2.5–6.0) of the 9 CONSORT items reported. Of those that reported a sample size calculation, the majority, 33 (73%), allowed for clustering, but just 15 (33%) allowed for time effects. There was a small increase in the proportions reporting a sample size calculation (from 64% before to 84% after publication of the CONSORT extension, p=0.07). The type of design (cohort or cross-sectional) was not reported clearly in the majority of studies, but cohort designs seemed to be most prevalent. Sample size calculations in cohort designs were particularly poor with only 3 out of 24 (13%) of these studies allowing for repeated measures. Discussion The quality of reporting of sample size items in stepped-wedge trials is suboptimal. There is an urgent need for dissemination of the appropriate guidelines for reporting and methodological development to match the proliferation of the use of this design in practice. Time effects and repeated measures should be considered in all SW-CRT power calculations, and there should be clarity in reporting trials as cohort or cross-sectional designs. PMID:26846897

Evaluating the Impact of Database Heterogeneity on Observational Study Results

PubMed Central

Madigan, David; Ryan, Patrick B.; Schuemie, Martijn; Stang, Paul E.; Overhage, J. Marc; Hartzema, Abraham G.; Suchard, Marc A.; DuMouchel, William; Berlin, Jesse A.

2013-01-01

Clinical studies that use observational databases to evaluate the effects of medical products have become commonplace. Such studies begin by selecting a particular database, a decision that published papers invariably report but do not discuss. Studies of the same issue in different databases, however, can and do generate different results, sometimes with strikingly different clinical implications. In this paper, we systematically study heterogeneity among databases, holding other study methods constant, by exploring relative risk estimates for 53 drug-outcome pairs and 2 widely used study designs (cohort studies and self-controlled case series) across 10 observational databases. When holding the study design constant, our analysis shows that estimated relative risks range from a statistically significant decreased risk to a statistically significant increased risk in 11 of 53 (21%) of drug-outcome pairs that use a cohort design and 19 of 53 (36%) of drug-outcome pairs that use a self-controlled case series design. This exceeds the proportion of pairs that were consistent across databases in both direction and statistical significance, which was 9 of 53 (17%) for cohort studies and 5 of 53 (9%) for self-controlled case series. Our findings show that clinical studies that use observational databases can be sensitive to the choice of database. More attention is needed to consider how the choice of data source may be affecting results. PMID:23648805

Optimising Web Site Designs for People with Learning Disabilities

ERIC Educational Resources Information Center

Williams, Peter; Hennig, Christian

2015-01-01

Much relevant internet-mediated information is inaccessible to people with learning disabilities because of difficulties in navigating the web. This paper reports on the methods undertaken to determine how information can be optimally presented for this cohort. Qualitative work is outlined where attributes relating to site layout affecting…

Does a Socio-Ecological School Model Promote Resilience in Primary Schools?

ERIC Educational Resources Information Center

Lee, Patricia C.; Stewart, Donald E.

2013-01-01

Background: This research investigates the extent to which the holistic, multistrategy "health-promoting school" (HPS) model using a resilience intervention can lead to improved resilience among students. Methods: A quasi-experimental design using a study cohort selected from 20 primary schools in Queensland, Australia was employed. Ten…

Designing for Learner Engagement with Computer Based Testing

ERIC Educational Resources Information Center

Walker, Richard; Handley, Zoe

2016-01-01

The issues influencing student engagement with high-stakes computer-based exams were investigated, drawing on feedback from two cohorts of international MA Education students encountering this assessment method for the first time. Qualitative data from surveys and focus groups on the students' examination experience were analysed, leading to the…

Age, Marital Processes, and Depressed Affect

ERIC Educational Resources Information Center

Bookwala, Jamila; Jacobs, Jamie

2004-01-01

Purpose: We examined age-cohort differences in the interrelationships among marital processes and depressed affect. Design and Methods: We used data from individuals in first marriages that participated in the National Survey of Families and Households (NSFH). The NSFH interviewed one adult per household of a nationally representative sample.…

Progression of Cohort Learning Style during an Intensive Education Program

ERIC Educational Resources Information Center

Compton, David A.; Compton, Cynthia M.

2017-01-01

The authors describe an intensive graduate program involving compressed classroom preparation followed by a period of experiential activities designed to reinforce and enhance the knowledge base. Beginning with a brief review of the andragogical issues, they describe methods undertaken to track learning styles via the Kolb Learning Styles…

Circulating microRNA-based screening tool for breast cancer

PubMed Central

Boukerroucha, Meriem; Fasquelle, Corinne; Thiry, Jérôme; Bovy, Nicolas; Struman, Ingrid; Geurts, Pierre; Collignon, Joëlle; Schroeder, Hélène; Kridelka, Frédéric; Lifrange, Eric; Jossa, Véronique

2016-01-01

Circulating microRNAs (miRNAs) are increasingly recognized as powerful biomarkers in several pathologies, including breast cancer. Here, their plasmatic levels were measured to be used as an alternative screening procedure to mammography for breast cancer diagnosis. A plasma miRNA profile was determined by RT-qPCR in a cohort of 378 women. A diagnostic model was designed based on the expression of 8 miRNAs measured first in a profiling cohort composed of 41 primary breast cancers and 45 controls, and further validated in diverse cohorts composed of 108 primary breast cancers, 88 controls, 35 breast cancers in remission, 31 metastatic breast cancers and 30 gynecologic tumors. A receiver operating characteristic curve derived from the 8-miRNA random forest based diagnostic tool exhibited an area under the curve of 0.81. The accuracy of the diagnostic tool remained unchanged considering age and tumor stage. The miRNA signature correctly identified patients with metastatic breast cancer. The use of the classification model on cohorts of patients with breast cancers in remission and with gynecologic cancers yielded prediction distributions similar to that of the control group. Using a multivariate supervised learning method and a set of 8 circulating miRNAs, we designed an accurate, minimally invasive screening tool for breast cancer. PMID:26734993

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

Crude incidence in two-phase designs in the presence of competing risks.

PubMed

Rebora, Paola; Antolini, Laura; Glidden, David V; Valsecchi, Maria Grazia

2016-01-11

In many studies, some information might not be available for the whole cohort, some covariates, or even the outcome, might be ascertained in selected subsamples. These studies are part of a broad category termed two-phase studies. Common examples include the nested case-control and the case-cohort designs. For two-phase studies, appropriate weighted survival estimates have been derived; however, no estimator of cumulative incidence accounting for competing events has been proposed. This is relevant in the presence of multiple types of events, where estimation of event type specific quantities are needed for evaluating outcome. We develop a non parametric estimator of the cumulative incidence function of events accounting for possible competing events. It handles a general sampling design by weights derived from the sampling probabilities. The variance is derived from the influence function of the subdistribution hazard. The proposed method shows good performance in simulations. It is applied to estimate the crude incidence of relapse in childhood acute lymphoblastic leukemia in groups defined by a genotype not available for everyone in a cohort of nearly 2000 patients, where death due to toxicity acted as a competing event. In a second example the aim was to estimate engagement in care of a cohort of HIV patients in resource limited setting, where for some patients the outcome itself was missing due to lost to follow-up. A sampling based approach was used to identify outcome in a subsample of lost patients and to obtain a valid estimate of connection to care. A valid estimator for cumulative incidence of events accounting for competing risks under a general sampling design from an infinite target population is derived.

Information content of household-stratified epidemics.

PubMed

Kinyanjui, T M; Pellis, L; House, T

2016-09-01

Household structure is a key driver of many infectious diseases, as well as a natural target for interventions such as vaccination programs. Many theoretical and conceptual advances on household-stratified epidemic models are relatively recent, but have successfully managed to increase the applicability of such models to practical problems. To be of maximum realism and hence benefit, they require parameterisation from epidemiological data, and while household-stratified final size data has been the traditional source, increasingly time-series infection data from households are becoming available. This paper is concerned with the design of studies aimed at collecting time-series epidemic data in order to maximize the amount of information available to calibrate household models. A design decision involves a trade-off between the number of households to enrol and the sampling frequency. Two commonly used epidemiological study designs are considered: cross-sectional, where different households are sampled at every time point, and cohort, where the same households are followed over the course of the study period. The search for an optimal design uses Bayesian computationally intensive methods to explore the joint parameter-design space combined with the Shannon entropy of the posteriors to estimate the amount of information in each design. For the cross-sectional design, the amount of information increases with the sampling intensity, i.e., the designs with the highest number of time points have the most information. On the other hand, the cohort design often exhibits a trade-off between the number of households sampled and the intensity of follow-up. Our results broadly support the choices made in existing epidemiological data collection studies. Prospective problem-specific use of our computational methods can bring significant benefits in guiding future study designs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

"Do I really want to do this?" Longitudinal cohort study participants' perspectives on postal survey design: a qualitative study.

PubMed

Harcombe, Helen; Derrett, Sarah; Herbison, Peter; McBride, David

2011-01-27

Randomised controlled trials have investigated aspects of postal survey design yet cannot elaborate on reasons behind participants' decision making and survey behaviour. This paper reports participants' perspectives of the design of, and participation in, a longitudinal postal cohort survey. It describes strengths and weaknesses in study design from the perspectives of study participants and aims to contribute to the: 1) design of future cohort surveys and questionnaires generally and, 2) design of cohort surveys for people with musculoskeletal disorders (MSDs) specifically. In-depth interviews explored the design of postal surveys previously completed by participants. Interviews used open ended questioning with a topic guide for prompts if areas of interest were not covered spontaneously. Thematic data analysis was undertaken based on the framework method. A second researcher verified all coding. Data from fourteen interviews were analysed within three main themes; participation, survey design and survey content. One of the main findings was the importance of clear communication aimed at the correct audience both when inviting potential participants to take part and within the survey itself. Providing enough information about the study, having a topic of interest and an explanation of likely benefits of the study were important when inviting people to participate. The neutrality of the survey and origination from a reputable source were both important; as was an explanation about why information was being collected within the survey itself. Study findings included participants' impressions when invited to take part, why they participated, the acceptability of follow-up of non-responders and why participants completed the follow-up postal survey. Also discussed were participants' first impression of the survey, its length, presentation and participants' views about specific questions within the survey. Ideas generated in this study provide an insight into participants' decision making and survey behaviour and may enhance the acceptability of future surveys to potential participants. As well as clear communication, participants valued incentives and survey questions that were relevant to them. However, opinions varied as to the preferred format for responses with some advising more opportunity for open-ended feedback. We also found that some standard format questions can raise quandaries for individual participants.

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

Design and Cohort Characteristics of the Social Spectrum Study: A Multicenter Study of the Autism Spectrum among Clinically Referred Children

ERIC Educational Resources Information Center

Duvekot, Jorieke; Hoopen, Leontine W.; Slappendel, Geerte; van der Ende, Jan; Verhulst, Frank C.; van der Sijde, Ad; Greaves-Lord, Kirstin

2017-01-01

This paper provides an overview of the design and cohort characteristics of the Social Spectrum Study: a clinical cohort study that used a two-phase sampling design to identify children at risk for ASD. After screening 1281 children aged 2.5-10 years who had been consecutively referred to one of six mental health services in the Netherlands,…

Cohort studies in health sciences librarianship.

PubMed

Eldredge, Jonathan

2002-10-01

What are the key characteristics of the cohort study design and its varied applications, and how can this research design be utilized in health sciences librarianship? The health, social, behavioral, biological, library, earth, and management sciences literatures were used as sources. All fields except for health sciences librarianship were scanned topically for either well-known or diverse applications of the cohort design. The health sciences library literature available to the author principally for the years 1990 to 2000, supplemented by papers or posters presented at annual meetings of the Medical Library Association. A narrative review for the health, social, behavioral, biological, earth, and management sciences literatures and a systematic review for health sciences librarianship literature for the years 1990 to 2000, with three exceptions, were conducted. The author conducted principally a manual search of the health sciences librarianship literature for the years 1990 to 2000 as part of this systematic review. The cohort design has been applied to answer a wide array of theoretical or practical research questions in the health, social, behavioral, biological, and management sciences. Health sciences librarianship also offers several major applications of the cohort design. The cohort design has great potential for answering research questions in the field of health sciences librarianship, particularly evidence-based librarianship (EBL), although that potential has not been fully explored.

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

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

Cohort profile: the Italian Network of Longitudinal Metropolitan Studies (IN-LiMeS), a multicentre cohort for socioeconomic inequalities in health monitoring

PubMed Central

Giorgi Rossi, Paolo; Spadea, Teresa; Pacelli, Barbara; Broccoli, Serena; Ballotari, Paola; Costa, Giuseppe; Zengarini, Nicolás; Agabiti, Nera; Bargagli, Anna Maria; Cacciani, Laura; Canova, Cristina; Cestari, Laura; Biggeri, Annibale; Grisotto, Laura; Terni, Gianna; Costanzo, Gianfranco; Mirisola, Concetta; Petrelli, Alessio

2018-01-01

Purpose The Italian Network of Longitudinal Metropolitan Studies (IN-LiMeS) is a system of integrated data on health outcomes, demographic and socioeconomic information, and represents a powerful tool to study health inequalities. Participants IN-LiMeS is a multicentre and multipurpose pool of metropolitan population cohorts enrolled in nine Italian cities: Turin, Venice, Reggio Emilia, Modena, Bologna, Florence, Leghorn, Prato and Rome. Data come from record linkage of municipal population registries, the 2001 population census, mortality registers and hospital discharge archives. Depending on the source of enrolment, cohorts can be closed or open. The census-based closed cohort design includes subjects resident in any of the nine cities at the 2001 census day; 4 466 655 individuals were enrolled in 2001 in the nine closed cohorts. The open cohort design includes subjects resident in 2001 or subsequently registered by birth or immigration until the latest available follow-up (currently 31 December 2013). The open cohort design is available for Turin, Venice, Reggio Emilia, Modena, Bologna, Prato and Rome. Detailed socioeconomic data are available for subjects enrolled in the census-based cohorts; information on demographic characteristics, education and citizenship is available from population registries. Findings to date The first IN-LiMeS application was the study of differentials in mortality between immigrants and Italians. Either using a closed cohort design (nine cities) or an open one (Turin and Reggio Emilia), individuals from high migration pressure countries generally showed a lower mortality risk. However, a certain heterogeneity between the nine cities was noted, especially among men, and an excess mortality risk was reported for some macroareas of origin and specific causes of death. Future plans We are currently working on the linkage of the 2011 population census data, the expansion of geographical coverage and the implementation of the open design in all the participating cohorts. PMID:29678981

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.

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 Central

Kubicek, Katrina; Weiss, George; Iverson, Ellen F.; Kipke, Michele D.

2010-01-01

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. However, the integration of qualitative data in mixed-methods research has been limited. This paper describes the qualitative 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. PMID:20222783

Accelerated longitudinal designs: An overview of modelling, power, costs and handling missing data.

PubMed

Galbraith, Sally; Bowden, Jack; Mander, Adrian

2017-02-01

Longitudinal studies are often used to investigate age-related developmental change. Whereas a single cohort design takes a group of individuals at the same initial age and follows them over time, an accelerated longitudinal design takes multiple single cohorts, each one starting at a different age. The main advantage of an accelerated longitudinal design is its ability to span the age range of interest in a shorter period of time than would be possible with a single cohort longitudinal design. This paper considers design issues for accelerated longitudinal studies. A linear mixed effect model is considered to describe the responses over age with random effects for intercept and slope parameters. Random and fixed cohort effects are used to cope with the potential bias accelerated longitudinal designs have due to multiple cohorts. The impact of other factors such as costs and the impact of dropouts on the power of testing or the precision of estimating parameters are examined. As duration-related costs increase relative to recruitment costs the best designs shift towards shorter duration and eventually cross-sectional design being best. For designs with the same duration but differing interval between measurements, we found there was a cutoff point for measurement costs relative to recruitment costs relating to frequency of measurements. Under our model of 30% dropout there was a maximum power loss of 7%.

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

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.

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

Multiple Trajectories of Successful Aging of Older and Younger Cohorts

ERIC Educational Resources Information Center

Hsu, Hui-Chuan; Jones, Bobby L.

2012-01-01

Purpose: The purpose of this study was to apply group-based trajectory analysis to identify multiple successful aging trajectories by multiple indicators and to examine the factors related to successful aging among the elderly population in Taiwan. Design and Methods: Nation-representative longitudinal data collected from 1993 to 2007 and…

Evidence That Classroom-Based Behavioral Interventions Reduce Pregnancy-Related School Dropout among Nairobi Adolescents

ERIC Educational Resources Information Center

Sarnquist, Clea; Sinclair, Jake; Omondi Mboya, Benjamin; Langat, Nickson; Paiva, Lee; Halpern-Felsher, Bonnie; Golden, Neville H.; Maldonado, Yvonne A.; Baiocchi, Michael T.

2017-01-01

Purpose: To evaluate the effect of behavioral, empowerment-focused interventions on the incidence of pregnancy-related school dropout among girls in Nairobi's informal settlements. Method: Retrospective data on pregnancy-related school dropout from two cohorts were analyzed using a matched-pairs quasi-experimental design. The primary outcome was…

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:…

Eliciting Web Site Preferences of People with Learning Disabilities

ERIC Educational Resources Information Center

Williams, Peter

2017-01-01

The Internet can be an excellent tool to help people with learning disabilities access relevant and appropriately written information. However, little work has been undertaken to ascertain web design or content preferences for this cohort. This paper examines methods to address this issue. Twenty five participants were presented with three web…

Destination Unknown? Study Choices and Graduate Destinations of Hungarian Youth in Slovakia

ERIC Educational Resources Information Center

Pásztor, Adél

2018-01-01

Focusing on Hungarian minority youth in a rural Slovakian setting, this article analyses their higher education aspirations and choices amidst significant economic, political and educational reforms. Relying on mixed methods and a longitudinal design, the research follows a cohort of high school students from their last year of secondary school…

Filipino women's diet and health study (FiLWHEL): design and methods.

PubMed

Abris, Grace P; Hong, Sangmo; Provido, Sherlyn Mae P; Lee, Jung Eun; Lee, Chang Beom

2017-02-01

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). 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. 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.

Reliability of dose volume constraint inference from clinical data.

PubMed

Lutz, C M; Møller, D S; Hoffmann, L; Knap, M M; Alber, M

2017-04-21

Dose volume histogram points (DVHPs) frequently serve as dose constraints in radiotherapy treatment planning. An experiment was designed to investigate the reliability of DVHP inference from clinical data for multiple cohort sizes and complication incidence rates. The experimental background was radiation pneumonitis in non-small cell lung cancer and the DVHP inference method was based on logistic regression. From 102 NSCLC real-life dose distributions and a postulated DVHP model, an 'ideal' cohort was generated where the most predictive model was equal to the postulated model. A bootstrap and a Cohort Replication Monte Carlo (CoRepMC) approach were applied to create 1000 equally sized populations each. The cohorts were then analyzed to establish inference frequency distributions. This was applied to nine scenarios for cohort sizes of 102 (1), 500 (2) to 2000 (3) patients (by sampling with replacement) and three postulated DVHP models. The Bootstrap was repeated for a 'non-ideal' cohort, where the most predictive model did not coincide with the postulated model. The Bootstrap produced chaotic results for all models of cohort size 1 for both the ideal and non-ideal cohorts. For cohort size 2 and 3, the distributions for all populations were more concentrated around the postulated DVHP. For the CoRepMC, the inference frequency increased with cohort size and incidence rate. Correct inference rates  >[Formula: see text] were only achieved by cohorts with more than 500 patients. Both Bootstrap and CoRepMC indicate that inference of the correct or approximate DVHP for typical cohort sizes is highly uncertain. CoRepMC results were less spurious than Bootstrap results, demonstrating the large influence that randomness in dose-response has on the statistical analysis.

Reliability of dose volume constraint inference from clinical data

NASA Astrophysics Data System (ADS)

Lutz, C. M.; Møller, D. S.; Hoffmann, L.; Knap, M. M.; Alber, M.

2017-04-01

Dose volume histogram points (DVHPs) frequently serve as dose constraints in radiotherapy treatment planning. An experiment was designed to investigate the reliability of DVHP inference from clinical data for multiple cohort sizes and complication incidence rates. The experimental background was radiation pneumonitis in non-small cell lung cancer and the DVHP inference method was based on logistic regression. From 102 NSCLC real-life dose distributions and a postulated DVHP model, an ‘ideal’ cohort was generated where the most predictive model was equal to the postulated model. A bootstrap and a Cohort Replication Monte Carlo (CoRepMC) approach were applied to create 1000 equally sized populations each. The cohorts were then analyzed to establish inference frequency distributions. This was applied to nine scenarios for cohort sizes of 102 (1), 500 (2) to 2000 (3) patients (by sampling with replacement) and three postulated DVHP models. The Bootstrap was repeated for a ‘non-ideal’ cohort, where the most predictive model did not coincide with the postulated model. The Bootstrap produced chaotic results for all models of cohort size 1 for both the ideal and non-ideal cohorts. For cohort size 2 and 3, the distributions for all populations were more concentrated around the postulated DVHP. For the CoRepMC, the inference frequency increased with cohort size and incidence rate. Correct inference rates  >85 % were only achieved by cohorts with more than 500 patients. Both Bootstrap and CoRepMC indicate that inference of the correct or approximate DVHP for typical cohort sizes is highly uncertain. CoRepMC results were less spurious than Bootstrap results, demonstrating the large influence that randomness in dose-response has on the statistical analysis.

A rule-based, dose-finding design for use in stroke rehabilitation research: methodological development.

PubMed

Colucci, E; Clark, A; Lang, C E; Pomeroy, V M

2017-12-01

Dose-optimisation studies as precursors to clinical trials are rare in stroke rehabilitation. To develop a rule-based, dose-finding design for stroke rehabilitation research. 3+3 rule-based, dose-finding study. Dose escalation/de-escalation was undertaken according to preset rules and a mathematical sequence (modified Fibonacci sequence). The target starting daily dose was 50 repetitions for the first cohort. Adherence was recorded by an electronic counter. At the end of the 2-week training period, the adherence record indicated dose tolerability (adherence to target dose) and the outcome measure indicated dose benefit (10% increase in motor function). The preset increment/decrease and checking rules were then applied to set the dose for the subsequent cohort. The process was repeated until preset stopping rules were met. Participants had a mean age of 68 (range 48 to 81) years, and were a mean of 70 (range 9 to 289) months post stroke with moderate upper limb paresis. A custom-built model of exercise-based training to enhance ability to open the paretic hand. Repetitions per minute of extension/flexion of paretic digits against resistance. Usability of the preset rules and whether the maximally tolerated dose was identifiable. Five cohorts of three participants were involved. Discernibly different doses were set for each subsequent cohort (i.e. 50, 100, 167, 251 and 209 repetitions/day). The maximally tolerated dose for the model training task was 209 repetitions/day. This dose-finding design is a feasible method for use in stroke rehabilitation research. Copyright © 2017 Chartered Society of Physiotherapy. All rights reserved.

Cohort studies in health sciences librarianship

PubMed Central

Eldredge, Jonathan

2002-01-01

Question: What are the key characteristics of the cohort study design and its varied applications, and how can this research design be utilized in health sciences librarianship? Data Sources: The health, social, behavioral, biological, library, earth, and management sciences literatures were used as sources. Study Selection: All fields except for health sciences librarianship were scanned topically for either well-known or diverse applications of the cohort design. The health sciences library literature available to the author principally for the years 1990 to 2000, supplemented by papers or posters presented at annual meetings of the Medical Library Association. Data Extraction: A narrative review for the health, social, behavioral, biological, earth, and management sciences literatures and a systematic review for health sciences librarianship literature for the years 1990 to 2000, with three exceptions, were conducted. The author conducted principally a manual search of the health sciences librarianship literature for the years 1990 to 2000 as part of this systematic review. Main Results: The cohort design has been applied to answer a wide array of theoretical or practical research questions in the health, social, behavioral, biological, and management sciences. Health sciences librarianship also offers several major applications of the cohort design. Conclusion: The cohort design has great potential for answering research questions in the field of health sciences librarianship, particularly evidence-based librarianship (EBL), although that potential has not been fully explored. PMID:12398244

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

A Controlled Evaluation of a High School Biomedical Pipeline Program: Design and Methods

NASA Astrophysics Data System (ADS)

Winkleby, Marilyn A.; Ned, Judith; Ahn, David; Koehler, Alana; Fagliano, Kathleen; Crump, Casey

2014-02-01

Given limited funding for school-based science education, non-school-based programs have been developed at colleges and universities to increase the number of students entering science- and health-related careers and address critical workforce needs. However, few evaluations of such programs have been conducted. We report the design and methods of a controlled trial to evaluate the Stanford Medical Youth Science Program's Summer Residential Program (SRP), a 25-year-old university-based biomedical pipeline program. This 5-year matched cohort study uses an annual survey to assess educational and career outcomes among four cohorts of students who participate in the SRP and a matched comparison group of applicants who were not chosen to participate in the SRP. Matching on sociodemographic and academic background allows control for potential confounding. This design enables the testing of whether the SRP has an independent effect on educational- and career-related outcomes above and beyond the effects of other factors such as gender, ethnicity, socioeconomic background, and pre-intervention academic preparation. The results will help determine which curriculum components contribute most to successful outcomes and which students benefit most. After 4 years of follow-up, the results demonstrate high response rates from SRP participants and the comparison group with completion rates near 90 %, similar response rates by gender and ethnicity, and little attrition with each additional year of follow-up. This design and methods can potentially be replicated to evaluate and improve other biomedical pipeline programs, which are increasingly important for equipping more students for science- and health-related careers.

A CONTROLLED EVALUATION OF A HIGH SCHOOL BIOMEDICAL PIPELINE PROGRAM: DESIGN AND METHODS.

PubMed

Winkleby, Marilyn A; Ned, Judith; Ahn, David; Koehler, Alana; Fagliano, Kathleen; Crump, Casey

2014-02-01

Given limited funding for school-based science education, non-school-based programs have been developed at colleges and universities to increase the number of students entering science- and health-related careers and address critical workforce needs. However, few evaluations of such programs have been conducted. We report the design and methods of a controlled trial to evaluate the Stanford Medical Youth Science Program's Summer Residential Program (SRP), a 25-year-old university-based biomedical pipeline program. This 5-year matched cohort study uses an annual survey to assess educational and career outcomes among four cohorts of students who participate in the SRP and a matched comparison group of applicants who were not chosen to participate in the SRP. Matching on sociodemographic and academic background allows control for potential confounding. This design enables the testing of whether the SRP has an independent effect on educational- and career-related outcomes above and beyond the effects of other factors such as gender, ethnicity, socioeconomic background, and pre-intervention academic preparation. The results will help determine which curriculum components contribute most to successful outcomes and which students benefit most. After 4 years of follow-up, the results demonstrate high response rates from SRP participants and the comparison group with completion rates near 90%, similar response rates by gender and ethnicity, and little attrition with each additional year of follow-up. This design and methods can potentially be replicated to evaluate and improve other biomedical pipeline programs, which are increasingly important for equipping more students for science- and health-related careers.

A CONTROLLED EVALUATION OF A HIGH SCHOOL BIOMEDICAL PIPELINE PROGRAM: DESIGN AND METHODS

PubMed Central

Winkleby, Marilyn A.; Ned, Judith; Ahn, David; Koehler, Alana; Fagliano, Kathleen; Crump, Casey

2013-01-01

Given limited funding for school-based science education, non-school-based programs have been developed at colleges and universities to increase the number of students entering science- and health-related careers and address critical workforce needs. However, few evaluations of such programs have been conducted. We report the design and methods of a controlled trial to evaluate the Stanford Medical Youth Science Program’s Summer Residential Program (SRP), a 25-year-old university-based biomedical pipeline program. This 5-year matched cohort study uses an annual survey to assess educational and career outcomes among four cohorts of students who participate in the SRP and a matched comparison group of applicants who were not chosen to participate in the SRP. Matching on sociodemographic and academic background allows control for potential confounding. This design enables the testing of whether the SRP has an independent effect on educational- and career-related outcomes above and beyond the effects of other factors such as gender, ethnicity, socioeconomic background, and pre-intervention academic preparation. The results will help determine which curriculum components contribute most to successful outcomes and which students benefit most. After 4 years of follow-up, the results demonstrate high response rates from SRP participants and the comparison group with completion rates near 90%, similar response rates by gender and ethnicity, and little attrition with each additional year of follow-up. This design and methods can potentially be replicated to evaluate and improve other biomedical pipeline programs, which are increasingly important for equipping more students for science- and health-related careers. PMID:24563603

Recent progresses in outcome-dependent sampling with failure time data.

PubMed

Ding, Jieli; Lu, Tsui-Shan; Cai, Jianwen; Zhou, Haibo

2017-01-01

An outcome-dependent sampling (ODS) design is a retrospective sampling scheme where one observes the primary exposure variables with a probability that depends on the observed value of the outcome variable. When the outcome of interest is failure time, the observed data are often censored. By allowing the selection of the supplemental samples depends on whether the event of interest happens or not and oversampling subjects from the most informative regions, ODS design for the time-to-event data can reduce the cost of the study and improve the efficiency. We review recent progresses and advances in research on ODS designs with failure time data. This includes researches on ODS related designs like case-cohort design, generalized case-cohort design, stratified case-cohort design, general failure-time ODS design, length-biased sampling design and interval sampling design.

Recent progresses in outcome-dependent sampling with failure time data

PubMed Central

Ding, Jieli; Lu, Tsui-Shan; Cai, Jianwen; Zhou, Haibo

2016-01-01

An outcome-dependent sampling (ODS) design is a retrospective sampling scheme where one observes the primary exposure variables with a probability that depends on the observed value of the outcome variable. When the outcome of interest is failure time, the observed data are often censored. By allowing the selection of the supplemental samples depends on whether the event of interest happens or not and oversampling subjects from the most informative regions, ODS design for the time-to-event data can reduce the cost of the study and improve the efficiency. We review recent progresses and advances in research on ODS designs with failure time data. This includes researches on ODS related designs like case–cohort design, generalized case–cohort design, stratified case–cohort design, general failure-time ODS design, length-biased sampling design and interval sampling design. PMID:26759313

Using a multi-user virtual simulation to promote science content: Mastery, scientific reasoning, and academic self-efficacy in fifth grade science

NASA Astrophysics Data System (ADS)

Ronelus, Wednaud J.

The purpose of this study was to examine the impact of using a role-playing game versus a more traditional text-based instructional method on a cohort of general education fifth grade students' science content mastery, scientific reasoning abilities, and academic self-efficacy. This is an action research study that employs an embedded mixed methods design model, involving both quantitative and qualitative data. The study is guided by the critical design ethnography theoretical lens: an ethnographic process involving participatory design work aimed at transforming a local context while producing an instructional design that can be used in multiple contexts. The impact of an immersive 3D multi-user web-based educational simulation game on a cohort of fifth-grade students was examined on multiple levels of assessments--immediate, close, proximal and distal. A survey instrument was used to assess students' self-efficacy in technology and scientific inquiry. Science content mastery was assessed at the immediate (participation in game play), close (engagement in-game reports) and proximal (understanding of targeted concepts) levels; scientific reasoning was assessed at the distal (domain general critical thinking test) level. This quasi-experimental study used a convenient sampling method. Seven regular fifth-grade classes participated in this study. Three of the classes were the control group and the other four were the intervention group. A cohort of 165 students participated in this study. The treatment group contained 38 boys and 52 girls, and the control group contained 36 boys and 39 girls. Two-tailed t-test, Analysis of Covariance (ANCOVA), and Pearson Correlation were used to analyze data. The data supported the rejection of the null hypothesis for the three research questions. The correlational analyses showed strong relationship among three of the four variables. There were no correlations between gender and the three dependent variables. The findings of this study support the hypothesis that the intervention group students will obtain dramatically larger gains on the three measures: Cornell Critical Thinking Test, Curriculum-Oriented Test, and the Self-Efficacy in Technology and Science (SETS) survey.

Evaluating Long-Term Complex Professional Development: Using a Variation of the Cohort Control Design

ERIC Educational Resources Information Center

Sample Mcmeeking, Laura B.; Cobb, R. Brian; Basile, Carole

2010-01-01

This paper introduces a variation on the post-test only cohort control design and addresses questions concerning both the methodological credibility and the practical utility of employing this design variation in evaluations of large-scale complex professional development programmes in mathematics education. The original design and design…

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.

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.

Cohort profile: the Italian Network of Longitudinal Metropolitan Studies (IN-LiMeS), a multicentre cohort for socioeconomic inequalities in health monitoring.

PubMed

Caranci, Nicola; Di Girolamo, Chiara; Giorgi Rossi, Paolo; Spadea, Teresa; Pacelli, Barbara; Broccoli, Serena; Ballotari, Paola; Costa, Giuseppe; Zengarini, Nicolás; Agabiti, Nera; Bargagli, Anna Maria; Cacciani, Laura; Canova, Cristina; Cestari, Laura; Biggeri, Annibale; Grisotto, Laura; Terni, Gianna; Costanzo, Gianfranco; Mirisola, Concetta; Petrelli, Alessio

2018-04-20

The Italian Network of Longitudinal Metropolitan Studies (IN-LiMeS) is a system of integrated data on health outcomes, demographic and socioeconomic information, and represents a powerful tool to study health inequalities. IN-LiMeS is a multicentre and multipurpose pool of metropolitan population cohorts enrolled in nine Italian cities: Turin, Venice, Reggio Emilia, Modena, Bologna, Florence, Leghorn, Prato and Rome. Data come from record linkage of municipal population registries, the 2001 population census, mortality registers and hospital discharge archives. Depending on the source of enrolment, cohorts can be closed or open. The census-based closed cohort design includes subjects resident in any of the nine cities at the 2001 census day; 4 466 655 individuals were enrolled in 2001 in the nine closed cohorts. The open cohort design includes subjects resident in 2001 or subsequently registered by birth or immigration until the latest available follow-up (currently 31 December 2013). The open cohort design is available for Turin, Venice, Reggio Emilia, Modena, Bologna, Prato and Rome. Detailed socioeconomic data are available for subjects enrolled in the census-based cohorts; information on demographic characteristics, education and citizenship is available from population registries. The first IN-LiMeS application was the study of differentials in mortality between immigrants and Italians. Either using a closed cohort design (nine cities) or an open one (Turin and Reggio Emilia), individuals from high migration pressure countries generally showed a lower mortality risk. However, a certain heterogeneity between the nine cities was noted, especially among men, and an excess mortality risk was reported for some macroareas of origin and specific causes of death. We are currently working on the linkage of the 2011 population census data, the expansion of geographical coverage and the implementation of the open design in all the participating cohorts. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Modular design, application architecture, and usage of a self-service model for enterprise data delivery: The Duke Enterprise Data Unified Content Explorer (DEDUCE)

PubMed Central

Horvath, Monica M.; Rusincovitch, Shelley A.; Brinson, Stephanie; Shang, Howard C.; Evans, Steve; Ferranti, Jeffrey M.

2015-01-01

Purpose Data generated in the care of patients are widely used to support clinical research and quality improvement, which has hastened the development of self-service query tools. User interface design for such tools, execution of query activity, and underlying application architecture have not been widely reported, and existing tools reflect a wide heterogeneity of methods and technical frameworks. We describe the design, application architecture, and use of a self-service model for enterprise data delivery within Duke Medicine. Methods Our query platform, the Duke Enterprise Data Unified Content Explorer (DEDUCE), supports enhanced data exploration, cohort identification, and data extraction from our enterprise data warehouse (EDW) using a series of modular environments that interact with a central keystone module, Cohort Manager (CM). A data-driven application architecture is implemented through three components: an application data dictionary, the concept of “smart dimensions”, and dynamically-generated user interfaces. Results DEDUCE CM allows flexible hierarchies of EDW queries within a grid-like workspace. A cohort “join” functionality allows switching between filters based on criteria occurring within or across patient encounters. To date, 674 users have been trained and activated in DEDUCE, and logon activity shows a steady increase, with variability between months. A comparison of filter conditions and export criteria shows that these activities have different patterns of usage across subject areas. Conclusions Organizations with sophisticated EDWs may find that users benefit from development of advanced query functionality, complimentary to the user interfaces and infrastructure used in other well-published models. Driven by its EDW context, the DEDUCE application architecture was also designed to be responsive to source data and to allow modification through alterations in metadata rather than programming, allowing an agile response to source system changes. PMID:25051403

Effects of Progressive Addition Lens Wear on Digital Work in Pre-presbyopes

PubMed Central

Kee, Chea-su; Leung, Tsz Wing; Kan, Ka-hung; Lam, Christie Hang-I

2018-01-01

SIGNIFICANCE Growing popularity of handheld digital devices imposes significant challenges to our visual system and clinical management. This study aimed to determine the effects of lens design on parameters that may influence the refractive management of pre-presbyopic adult computer users. PURPOSE To determine the effects of wearing conventional single-vision lenses (SVL) versus progressive addition lenses (PAL) on the working distance and refractive status. METHODS Adult computer users, recruited from two age cohorts (18 to 25 years, n = 19; 30 to 40 years, n = 45), were prescribed SVLs and PALs designed for use with handheld digital devices. For each lens type, the working distance and refractive shift (post-task − pre-task) were measured immediately after lens delivery (T0) and after 1 month of lens wear (T1). Working distances were recorded with an automatic ultrasound device while the participants were playing a video game. Refractive status through the subjects' glasses was measured before (pre-task) and after playing the game (post-task). Questionnaires assessing the frequencies of 10 digital work–related visual symptoms were conducted for both lens types at T1. RESULTS Switching from SVL to PAL increased the working distance in both cohorts (mean ± SEM = 1.88 ± 0.60 cm; P = .002) and induced a small but significant positive refractive shift (+0.08 ± 0.04 D, P = .021) in the older cohort at T1. In the younger cohort, the changes in working distance due to the switching lens design were correlated with myopic error (r = +0.66, P = .002). In the older cohort, the changes in refractive shift due to switching lens design were correlated with amplitude of accommodation at both time points (r for T0 and T1 = −0.32 and −0.30, respectively; both P < .05). Progressive addition lens was rated as causing less “increased sensitivity to light” compared with SVL. CONCLUSIONS Switching from SVL to PAL increased the working distance and induced a positive refractive shift in the majority of pre-presbyopic adults. PMID:29683984

How Do Technology-Enhanced Inquiry Science Units Impact Classroom Learning?

ERIC Educational Resources Information Center

Lee, Hee-Sun; Linn, Marcia C.; Varma, Keisha; Liu, Ou Lydia

2010-01-01

We investigated how student understanding of complex science topics was impacted when 27 teachers switched from typical to inquiry instruction in a delayed cohort comparison design study. For the same set of science topics, the teachers used typical methods of instruction in the first year and online, visualization rich inquiry units in the second…

Facilitating Students' Conceptual Understanding of Boiling Using a Four-Step Constructivist Teaching Method

ERIC Educational Resources Information Center

Calik, Muammer

2008-01-01

The aim of the work presented here was to devise an activity associated with factors affecting boiling points. The intervention used a four-step constructivist-based teaching strategy, which was subsequently evaluated by a cohort of students. Data collection consisted of application of a purpose designed questionnaire consisting of four open-ended…

"What Do These Words Mean?": A Qualitative Approach to Explore Oral Health Literacy in Vietnamese Immigrant Mothers in Australia

ERIC Educational Resources Information Center

Arora, Amit; Nguyen, Deon; Do, Quang Vinh; Nguyen, Bao; Hilton, Glen; Do, Loc Giang; Bhole, Sameer

2014-01-01

Objective: This study, nested within a large cohort study, sought to explore how well Vietnamese mothers with pre-school children understood the dental health education material commonly available in New South Wales, Australia. Design: Qualitative research. Setting: Home-based interviews. Method: Vietnamese-speaking mothers ("n" = 24)…

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…

The Prevalence of Undiagnosed Geriatric Health Conditions among Adult Protective Service Clients

ERIC Educational Resources Information Center

Heath, John M.; Brown, Merle; Kobylarz, Fred A.; Castano, Susan

2005-01-01

Purpose: We sought to determine the prevalence of remediable health conditions from in-home geriatric assessments of referred adult protective service (APS) clients suffering elder mistreatment. Design and Methods: We used a retrospective cohort study of 211 APS clients (74% female; age, M = 77 years) in two central New Jersey counties. Results:…

Relative Immaturity and ADHD: Findings from Nationwide Registers, Parent- and Self-Reports

ERIC Educational Resources Information Center

Halldner, Linda; Tillander, Annika; Lundholm, Cecilia; Boman, Marcus; Långström, Niklas; Larsson, Henrik; Lichtenstein, Paul

2014-01-01

Background: We addressed if immaturity relative to peers reflected in birth month increases the likelihood of ADHD diagnosis and treatment. Methods: We linked nationwide Patient and Prescribed Drug Registers and used prospective cohort and nested case-control designs to study 6-69 year-old individuals in Sweden from July 2005 to December 2009…

Interventions to Reduce Distress in Adult Victims of Rape and Sexual Violence: A Systematic Review

ERIC Educational Resources Information Center

Regehr, Cheryl; Alaggia, Ramona; Dennis, Jane; Pitts, Annabel; Saini, Michael

2013-01-01

Objectives: This article presents a systematic evaluation of the effectiveness of interventions aimed at reducing distress in adult victims of rape and sexual violence. Method: Studies were eligible for the review if the assignment of study participants to experimental or control groups was by random allocation or parallel cohort design. Results:…

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.

Stargardt macular dystrophy: common ABCA4 mutations in South Africa—establishment of a rapid genetic test and relating risk to patients

PubMed Central

Nossek, Christel A.; Greenberg, L. Jacquie; Ramesar, Rajkumar S.

2012-01-01

Purpose Based on the previous indications of founder ATP-binding cassette sub-family A member 4 gene (ABCA4) mutations in a South African subpopulation, the purpose was to devise a mechanism for identifying common disease-causing mutations in subjects with ABCA4-associated retinopathies (AARs). Facilitating patient access to this data and determining the frequencies of the mutations in the South African population would enhance the current molecular diagnostic service offered. Methods The majority of subjects in this study were of Caucasian ancestry and affected with Stargardt macular dystrophy. The initial cohort consisted of DNA samples from 181 patients, and was screened using the ABCR400 chip. An assay was then designed to screen a secondary cohort of 72 patients for seven of the most commonly occurring ABCA4 mutations in this population. A total of 269 control individuals were also screened for the seven ABCA4 mutations. Results Microarray screening results from a cohort of 181 patients affected with AARs revealed that seven ABCA4 mutations (p.Arg152*, c.768G>T, p.Arg602Trp, p.Gly863Ala, p.Cys1490Tyr, c.5461–10T>C, and p.Leu2027Phe) occurred at a relatively high frequency. The newly designed genetic assay identified two of the seven disease-associated mutations in 28/72 patients in a secondary patient cohort. In the control cohort, 12/269 individuals were found to be heterozygotes, resulting in an estimated background frequency of these mutations in this particular population of 4.46 per 100 individuals. Conclusions The relatively high detection rate of seven ABCA4 mutations in the primary patient cohort led to the design and subsequent utility of a multiplex assay. This assay can be used as a viable screening tool and to reduce costs and laboratory time. The estimated background frequency of the seven ABCA4 mutations, together with the improved diagnostic service, could be used by counselors to facilitate clinical and genetic management of South African families with AARs. PMID:22328824

A nomogram to predict the survival of stage IIIA-N2 non-small cell lung cancer after surgery.

PubMed

Mao, Qixing; Xia, Wenjie; Dong, Gaochao; Chen, Shuqi; Wang, Anpeng; Jin, Guangfu; Jiang, Feng; Xu, Lin

2018-04-01

Postoperative survival of patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) is highly heterogeneous. Here, we aimed to identify variables associated with postoperative survival and develop a tool for survival prediction. A retrospective review was performed in the Surveillance, Epidemiology, and End Results database from January 2004 to December 2009. Significant variables were selected by use of the backward stepwise method. The nomogram was constructed with multivariable Cox regression. The model's performance was evaluated by concordance index and calibration curve. The model was validated via an independent cohort from the Jiangsu Cancer Hospital Lung Cancer Center. A total of 1809 patients with stage IIIA-N2 NSCLC who underwent surgery were included in the training cohort. Age, sex, grade, histology, tumor size, visceral pleural invasion, positive lymph nodes, lymph nodes examined, and surgery type (lobectomy vs pneumonectomy) were identified as significant prognostic variables using backward stepwise method. A nomogram was developed from the training cohort and validated using an independent Chinese cohort. The concordance index of the model was 0.673 (95% confidence interval, 0.654-0.692) in training cohort and 0.664 in validation cohort (95% confidence interval, 0.614-0.714). The calibration plot showed optimal consistency between nomogram predicted survival and observed survival. Survival analyses demonstrated significant differences between different subgroups stratified by prognostic scores. This nomogram provided the individual survival prediction for patients with stage IIIA-N2 NSCLC after surgery, which might benefit survival counseling for patients and clinicians, clinical trial design and follow-up, as well as postoperative strategy-making. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

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

Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research.

PubMed

Gong, Tong; Brew, Bronwyn; Sjölander, Arvid; Almqvist, Catarina

2017-07-01

Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs. Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs. When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma. We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.

Commentary: considerations for using the 'Trials within Cohorts' design in a clinical trial of an investigational medicinal product.

PubMed

Bibby, Anna C; Torgerson, David J; Leach, Samantha; Lewis-White, Helen; Maskell, Nick A

2018-01-08

The 'trials within cohorts' (TwiC) design is a pragmatic approach to randomised trials in which trial participants are randomly selected from an existing cohort. The design has multiple potential benefits, including the option of conducting multiple trials within the same cohort. To date, the TwiC design methodology been used in numerous clinical settings but has never been applied to a clinical trial of an investigational medicinal product (CTIMP). We have recently secured the necessary approvals to undertake the first CTIMP using the TwiC design. In this paper, we describe some of the considerations and modifications required to ensure such a trial is compliant with Good Clinical Practice and international clinical trials regulations. We advocate using a two-stage consent process and using the consent stages to explicitly differentiate between trial participants and cohort participants who are providing control data. This distinction ensured compliance but had consequences with respect to costings, recruitment and the trial assessment schedule. We have demonstrated that it is possible to secure ethical and regulatory approval for a CTIMP TwiC. By including certain considerations at the trial design stage, we believe this pragmatic and efficient methodology could be utilised in other CTIMPs in future.

Recruitment and Retention Strategies for Minority or Poor Clinical Research Participants: Lessons From the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study

PubMed Central

Ejiogu, Ngozi; Norbeck, Jennifer H.; Mason, Marc A.; Cromwell, Bridget C.; Zonderman, Alan B.; Evans, Michele K.

2011-01-01

Purpose of the study: Investigating health disparities requires studies designed to recruit and retain racially and socioeconomically diverse cohorts. It is critical to address the barriers that disproportionately affect participation in clinical research by minorities and the socioeconomically disadvantaged. This study sought to identify and rectify these barriers to recruit and retain a biracial (African American and non-Hispanic White) and socioeconomically diverse cohort for a longitudinal study. Design and Method: The Healthy Aging in Neighborhoods of Diversity across the Life Span study is a 20-year longitudinal examination of how race and socioeconomic status influence the development of age-related health disparities. One goal was to create a multifactorial recruitment and retention strategy. The recruitment paradigm targeted known barriers and identified those unique to the study's urban environment. The retention paradigm mirrored the recruitment plan but was based on specifically developed approaches. Results: This cohort recruitment required attention to developing community partnerships, designing the research study to meet the study hypotheses and to provide benefit to participants, providing a safe community-based site for the research and creating didactics to develop staff cultural proficiency. These efforts facilitated study implementation and enhanced recruitment resulting in accrual of a biracial and socioeconomically diverse cohort of 3,722 participants. Implications: Recruiting and retaining minority or poor research participants is challenging but possible. The essential facets include clear communication of the research hypothesis, focus on providing a direct benefit for participants, and selection of a hypothesis that is directly relevant to the community studied PMID:21565817

Breaking Cancer Bad News to Patients With Cancer: A Comprehensive Perspective of Patients, Their Relatives, and the Public—Example From a Middle Eastern Country

PubMed Central

Zekri, Jamal

2016-01-01

Purpose Empowering patients with cancer requires that they be continuously informed about their condition. In some Eastern cultures, this concept is often opposed by caregivers. We aim to compare the extent of disclosure desired by actual and presumed patients with cancer and their relatives in our practice. Methods Nine questions reflecting possible bad news communication to patients from diagnosis to the end of life were designed to investigate the extent of desired disclosure and were answered by 100 patients (cohort I) and 103 accompanying relatives (cohort II) in an outpatient setting. In addition, 103 public participants attending a family medicine clinic (cohort III) each answered the questions from the perspective of a presumed patient (cohort IIIA) and the perspective of a relative (cohort IIIB). The primary end point was affirmative response to six or more questions (AR ≥ 6), reflecting a preference to be informed of the majority (≥ 67%) of possible bad news. Results AR ≥ 6 was reported in 85% of cohort I and 52% of cohort II (χ2 P < .001). On multivariable analysis, AR ≥ 6 showed significant association with being a patient (in cohorts I and II) and having nonmetastatic disease (only in cohort I). In the public cohort, AR ≥ 6 was reported in 91% in cohort IIIA and 63% in cohort IIIB (χ2 P < .001). On multivariable analysis, AR ≥ 6 in cohort III was significantly associated with being a presumed patient and having at least a college education. Conclusion Patients desire disclosure of the majority of cancer-related bad news. This is in contrast to the views and requests of relatives. The public participants would also desire similar disclosure if they were to be diagnosed with cancer. PMID:28717713

[Application of nested case-control study on safe evaluation of post-marketing traditional Chinese medicine injection].

PubMed

Xiao, Ying; Zhao, Yubin; Xie, Yanming

2011-10-01

The nested case-control study design (or the case-control in a cohort study) is described here as a new study design used in safe evaluation of post-marketing traditional Chinese medicine injection. In the nested case-control study, cases of a disease that occur in a defined cohort are identified and, for each, a specified number of matched controls is selected from among those in the cohort who have not developed the disease by the time of disease occurrence in the case. For many research questions, the nested case-control design potentially offers impressive reductions in costs and efforts of data collection and analysis compared with the full cohort approach, with relatively minor loss in statistical efficiency. The nested case-control design is particularly advantageous for studies in safe evaluation of post-marketing traditional Chinese medicine injection. Some examples of the application of nested case-control study were given.

Ascertainment and verification of end-stage renal disease and end-stage liver disease in the north american AIDS cohort collaboration on research and design.

PubMed

Kitahata, Mari M; Drozd, Daniel R; Crane, Heidi M; Van Rompaey, Stephen E; Althoff, Keri N; Gange, Stephen J; Klein, Marina B; Lucas, Gregory M; Abraham, Alison G; Lo Re, Vincent; McReynolds, Justin; Lober, William B; Mendes, Adell; Modur, Sharada P; Jing, Yuezhou; Morton, Elizabeth J; Griffith, Margaret A; Freeman, Aimee M; Moore, Richard D

2015-01-01

The burden of HIV disease has shifted from traditional AIDS-defining illnesses to serious non-AIDS-defining comorbid conditions. Research aimed at improving HIV-related comorbid disease outcomes requires well-defined, verified clinical endpoints. We developed methods to ascertain and verify end-stage renal disease (ESRD) and end-stage liver disease (ESLD) and validated screening algorithms within the largest HIV cohort collaboration in North America (NA-ACCORD). Individuals who screened positive among all participants in twelve cohorts enrolled between January 1996 and December 2009 underwent medical record review to verify incident ESRD or ESLD using standardized protocols. We randomly sampled 6% of contributing cohorts to determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ESLD and ESRD screening algorithms in a validation subcohort. Among 43,433 patients screened for ESRD, 822 screened positive of which 620 met clinical criteria for ESRD. The algorithm had 100% sensitivity, 99% specificity, 82% PPV, and 100% NPV for ESRD. Among 41,463 patients screened for ESLD, 2,024 screened positive of which 645 met diagnostic criteria for ESLD. The algorithm had 100% sensitivity, 95% specificity, 27% PPV, and 100% NPV for ESLD. Our methods proved robust for ascertainment of ESRD and ESLD in persons infected with HIV.

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.

Analysis of Formant Frequencies in Patients with Oral or Oropharyngeal Cancers Treated by Glossectomy

ERIC Educational Resources Information Center

Kazi, Rehan; Prasad, Vyas M. N.; Kanagalingam, Jeeve; Georgalas, Christos; Venkitaraman, Ramachandran; Nutting, Christopher M.; Clarke, Peter; Rhys-Evans, Peter; Harrington, Kevin J.

2007-01-01

Aims: To compare voice quality as defined by formant analysis using a sustained vowel in patients who have undergone a partial glossectomy with a group of normal subjects. Methods & Procedures: The design consisted of a single centre, cross-sectional cohort study. The setting was an Adult Tertiary Referral Unit. A total of 26 patients (19…

The Relative Benefits and Cost of Medicaid Home- and Community-Based Services in Florida

ERIC Educational Resources Information Center

Mitchell, Glenn, II; Salmon, Jennifer R.; Polivka, Larry; Soberon-Ferrer, Horacio

2006-01-01

Purpose: We compared inpatient days, nursing home days, and total Medicaid claims for five Medicaid-funded home- and community-based services (HCBS) programs for in-home and assisted living services in Florida. Design and Methods: We studied a single cohort of Medicaid enrollees in Florida aged 60 and older, who were enrolled for the first time in…

Differences in Learning Preferences by Generational Cohort: Implications for Instructional Design in Corporate Web-Based Learning

ERIC Educational Resources Information Center

Kriegel, Jessica

2013-01-01

In today's global and high-tech economy, the primary contributing factor to sustainable competitive advantage is the strategic development of employees, an organization's only unique asset. However, with four generations actively present in the workforce and the proliferation of web-based learning as a key method for developing…

The Effect of Self-Reported and Performance-Based Functional Impairment on Future Hospital Costs of Community-Dwelling Older Persons

ERIC Educational Resources Information Center

Reuben, David B.; Seeman, Teresa E.; Keeler, Emmett; Hayes, Risa P.; Bowman, Lee; Sewall, Ase; Hirsch, Susan H.; Wallace, Robert B.; Guralnik, Jack M.

2004-01-01

Purpose: We determined the prognostic value of self-reported and performance-based measurement of function, including functional transitions and combining different measurement approaches, on utilization. Design and Methods: Our cohort study used the 6th, 7th, and 10th waves of three sites of the Established Populations for Epidemiologic Studies…

Adapting the Community of Inquiry Survey for an Online Graduate Program: Implications for Online Programs

ERIC Educational Resources Information Center

Kumar, Swapna; Ritzhaupt, Albert D.

2014-01-01

A cohort-based online professional doctorate program that consisted of both online coursework and research activities was designed using Garrison et al's community of inquiry (CoI) framework. The evaluation of the program proved a challenge because all existing CoI assessment methods in the past have dealt with online courses, not with online…

NWHSS Implement Family Member Assessment Component in the Millennium Cohort Study

DTIC Science & Technology

2014-12-01

Surveys: The Tailored Design Method, 3rd edition , Hoboken, NJ, John Wiley & Sons. Dillman D.A., Smyth J.D., Christian L.M., O’Neill A. (2008) Will a...TYPE Final Report 3 . DATES COVERED (From - To) 28 Sep 2009 – 27 Sep 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER NWHSS...23 3 . Key Research Accomplishments

The Role of Perceived Control in Explaining Depressive Symptoms Associated with Driving Cessation in a Longitudinal Study

ERIC Educational Resources Information Center

Windsor, Timothy D.; Anstey, Kaarin J.; Butterworth, Peter; Luszcz, Mary A.; Andrews, Gary R.

2007-01-01

Purpose: The purpose of this article was to investigate the role of control beliefs in mediating the relationship between driving cessation and change in depressive symptoms in a population-based sample of older adults. Design and Methods: We report results from a prospective, community-based cohort study that included two waves of data collected…

MICE 2.0: Designing Multimedia Content to Foster Active Learning in a Malaysian Classroom

ERIC Educational Resources Information Center

Neo, Tse-Kian; Neo, Mai; Kwok, Wai-Jing; Tan, Yeen-Ju; Lai, Chen-Haw; Zarina, Che Embi

2012-01-01

With the strong emphasis of social constructivism, many educators are finding new ways to stimulate and enhance social activities within the classroom. One such method is the use of cooperative learning. A cohort of students worked in small teams cooperatively to complete an assignment while using blogs to document and reflect their work.…

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.

Understanding resilience in same-sex parented families: the work, love, play study

PubMed Central

2010-01-01

Background While families headed by same-sex couples have achieved greater public visibility in recent years, there are still many challenges for these families in dealing with legal and community contexts that are not supportive of same-sex relationships. The Work, Love, Play study is a large longitudinal study of same-sex parents. It aims to investigate many facets of family life among this sample and examine how they change over time. The study focuses specifically on two key areas missing from the current literature: factors supporting resilience in same-sex parented families; and health and wellbeing outcomes for same-sex couples who undergo separation, including the negotiation of shared parenting arrangements post-separation. The current paper aims to provide a comprehensive overview of the design and methods of this longitudinal study and discuss its significance. Methods/Design The Work, Love, Play study is a mixed design, three wave, longitudinal cohort study of same-sex attracted parents. The sample includes lesbian, gay, bisexual and transgender parents in Australia and New Zealand (including single parents within these categories) caring for any children under the age of 18 years. The study will be conducted over six years from 2008 to 2014. Quantitative data are to be collected via three on-line surveys in 2008, 2010 and 2012 from the cohort of parents recruited in Wave1. Qualitative data will be collected via interviews with purposively selected subsamples in 2012 and 2013. Data collection began in 2008 and 355 respondents to Wave One of the study have agreed to participate in future surveys. Work is currently underway to increase this sample size. The methods and survey instruments are described. Discussion This study will make an important contribution to the existing research on same-sex parented families. Strengths of the study design include the longitudinal method, which will allow understanding of changes over time within internal family relationships and social supports. Further, the mixed method design enables triangulation of qualitative and quantitative data. A broad recruitment strategy has already enabled a large sample size with the inclusion of both gay men and lesbians. PMID:20211027

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.

Sample size for post-marketing safety studies based on historical controls.

PubMed

Wu, Yu-te; Makuch, Robert W

2010-08-01

As part of a drug's entire life cycle, post-marketing studies are an important part in the identification of rare, serious adverse events. Recently, the US Food and Drug Administration (FDA) has begun to implement new post-marketing safety mandates as a consequence of increased emphasis on safety. The purpose of this research is to provide exact sample size formula for the proposed hybrid design, based on a two-group cohort study with incorporation of historical external data. Exact sample size formula based on the Poisson distribution is developed, because the detection of rare events is our outcome of interest. Performance of exact method is compared to its approximate large-sample theory counterpart. The proposed hybrid design requires a smaller sample size compared to the standard, two-group prospective study design. In addition, the exact method reduces the number of subjects required in the treatment group by up to 30% compared to the approximate method for the study scenarios examined. The proposed hybrid design satisfies the advantages and rationale of the two-group design with smaller sample sizes generally required. 2010 John Wiley & Sons, Ltd.

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.

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

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

Improving Student Commitment to Healthcare-Related Design Practice by Improving the Studio Learning Experience.

PubMed

Tan, Lindsay; Hong, Miyoung; Albert, Taneshia West

2017-10-01

This case study explores the influence of the healthcare design studio experience on students' short-term professional goals as measured through rates of healthcare-related certification and internship/employment. The value and relevance of interior design is evident in the healthcare design sector. However, interior design students may not perceive this value if it is not communicated through their design education. Students' experience in the design studio plays a crucial role in determining career choices, and students may be more committed to career goals when there is clear connection between major coursework and professional practice. The authors compared healthcare-related certification and internship/employment levels between two student cohorts in a capstone undergraduate interior design healthcare design studio course. The first cohort was led by the existing curriculum. The second cohort was led by the revised curriculum that specifically aimed at encouraging students to commit to healthcare-related design practice. When measured at 3 months from graduation, the second cohort, led by the revised curriculum, saw a 30% increase in Evidence-based Design Accreditation and Certification exam pass rates and a 40% increase in healthcare-related internship/employment. The challenge of interior design education is to instill in emerging professionals not only professional competence but also those professional attitudes that will make them better prepared to design spaces that improve quality of life, particularly in healthcare environments. The results exceeded the project goals, and so this could be considered a promising practice for courses focused on healthcare design education.

Evolution of epidemiologic methods and concepts in selected textbooks of the 20th century.

PubMed

Zhang, Fang F; Michaels, Desireé C; Mathema, Barun; Kauchali, Shuaib; Chatterjee, Anjan; Ferris, David C; James, Tamarra M; Knight, Jennifer; Dounel, Matthew; Tawfik, Hebatullah O; Frohlich, Janet A; Kuang, Li; Hoskin, Elena K; Veldman, Frederick J; Baldi, Giulia; Mlisana, Koleka P; Mametja, Lerole D; Diaz, Angela; Khan, Nealia L; Sternfels, Pamela; Sevigny, Jeffery J; Shamam, Asher; Morabia, Alfredo

2004-01-01

Textbooks are an expression of the state of development of a discipline at a given moment in time. By reviewing eight epidemiology textbooks published over the course of a century, we have attempted to trace the evolution of five epidemiologic concepts and methods: study design (cohort studies and case-control studies), confounding, bias, interaction and causal inference. Overall, these eight textbooks can be grouped into three generations. Greenwood (1935) and Hill (first edition 1937; version reviewed 1961)'s textbooks belong to the first generation, "early epidemiology", which comprise early definitions of bias and confounding. The second generation, "classic epidemiology", represented by the textbooks of Morris (first edition 1957; version reviewed 1964), MacMahon & Pugh (first edition 1960; version reviewed 1970), Susser (1973), and Lilienfeld & Lilienfeld (first edition 1976; version reviewed 1980), clarifies the properties of cohort and case-control study designs and the theory of disease causation. Miettinen (1985) and Rothman (1986)'s textbooks belong to a third generation, "modern epidemiology", presenting an integrated perspective on study designs and their measures of outcome, as well as distinguishing and formalizing the concepts of confounding and interaction. Our review demonstrates that epidemiology, as a scientific discipline, is in constant evolution and transformation. It is likely that new methodological tools, able to assess the complexity of the causes of human health, will be proposed in future generations of textbooks.

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

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

Cohort Default Rate Guide.

ERIC Educational Resources Information Center

Department of Education, Washington, DC. Default Management Div.

This guide is designed to assist schools with their Federal Family Education Loan Program (FFEL) and the William D. Ford Federal Direct Loan (Direct Loan) Program cohort default rate. The guide is a reference tool in understanding cohort default rates and processes. This guide incorporates two former guides, the "Draft Cohort Default Rate…

75 FR 37812 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

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Follow-up methods for retrospective cohort studies in New Zealand.

PubMed

Fawcett, Jackie; Garrett, Nick; Bates, Michael N

2002-01-01

To define a general methodology for maximising the success of follow-up processes for retrospective cohort studies in New Zealand, and to illustrate an approach to developing country-specific follow-up methodologies. We recently conducted a cohort study of mortality and cancer incidence in New Zealand professional fire fighters. A number of methods were used to trace vital status, including matching with records of the New Zealand Health Information Service (NZHIS), pension records of Work and Income New Zealand (WINZ), and electronic electoral rolls. Non-electronic methods included use of paper electoral rolls and the records of the Registrar of Births Deaths and Marriages. 95% of the theoretical person-years of follow-up of the cohort were traced using these methods. In terms of numbers of cohort members traced to end of follow-up, the most useful tracing methods were fire fighter employment records, the NZHIS, WINZ, and the electronic electoral rolls. The follow-up process used for the cohort study was highly successful. On the basis of this experience, we propose a generic, but flexible, model for follow-up of retrospective cohort studies in New Zealand. Similar models could be constructed for other countries. Successful follow-up of cohort studies is possible in New Zealand using established methods. This should encourage the use of cohort studies for the investigation of epidemiological issues. Similar models for follow-up processes could be constructed for other countries.

Research Methods in Healthcare Epidemiology and Antimicrobial Stewardship-Observational Studies.

PubMed

Snyder, Graham M; Young, Heather; Varman, Meera; Milstone, Aaron M; Harris, Anthony D; Munoz-Price, Silvia

2016-10-01

Observational studies compare outcomes among subjects with and without an exposure of interest, without intervention from study investigators. Observational studies can be designed as a prospective or retrospective cohort study or as a case-control study. In healthcare epidemiology, these observational studies often take advantage of existing healthcare databases, making them more cost-effective than clinical trials and allowing analyses of rare outcomes. This paper addresses the importance of selecting a well-defined study population, highlights key considerations for study design, and offers potential solutions including biostatistical tools that are applicable to observational study designs. Infect Control Hosp Epidemiol 2016;1-6.

Medication safety research by observational study design.

PubMed

Lao, Kim S J; Chui, Celine S L; Man, Kenneth K C; Lau, Wallis C Y; Chan, Esther W; Wong, Ian C K

2016-06-01

Observational studies have been recognised to be essential for investigating the safety profile of medications. Numerous observational studies have been conducted on the platform of large population databases, which provide adequate sample size and follow-up length to detect infrequent and/or delayed clinical outcomes. Cohort and case-control are well-accepted traditional methodologies for hypothesis testing, while within-individual study designs are developing and evolving, addressing previous known methodological limitations to reduce confounding and bias. Respective examples of observational studies of different study designs using medical databases are shown. Methodology characteristics, study assumptions, strengths and weaknesses of each method are discussed in this review.

SMART trial: A randomized clinical trial of self-monitoring in behavioral weight management-design and baseline findings

PubMed Central

Burke, Lora E.; Styn, Mindi A.; Glanz, Karen; Ewing, Linda J.; Elci, Okan U.; Conroy, Margaret B.; Sereika, Susan M.; Acharya, Sushama D.; Music, Edvin; Keating, Alison L.; Sevick, Mary Ann

2009-01-01

Background The primary form of treatment for obesity today is behavioral therapy. Self-monitoring diet and physical activity plays an important role in interventions targeting behavior and weight change. The SMART weight loss trial examined the impact of replacing the standard paper record used for self-monitoring with a personal digital assistant (PDA). This paper describes the design, methods, intervention, and baseline sample characteristics of the SMART trial. Methods The SMART trial used a 3-group design to determine the effects of different modes of self-monitoring on short- and long-term weight loss and on adherence to self-monitoring in a 24-month intervention. Participants were randomized to one of three conditions (1) use of a standard paper record (PR); (2) use of a PDA with dietary and physical activity software (PDA); or (3), use of a PDA with the same software plus a customized feedback program (PDA + FB). Results We screened 704 individuals and randomized 210. There were statistically but not clinically significant differences among the three cohorts in age, education, HDL cholesterol, blood glucose and systolic blood pressure. At 24 months, retention rate for the first of three cohorts was 90%. Conclusions To the best of our knowledge, the SMART trial is the first large study to compare different methods of self-monitoring in a behavioral weight loss intervention and to compare the use of PDAs to conventional paper records. This study has the potential to reveal significant details about self-monitoring patterns and whether technology can improve adherence to this vital intervention component. PMID:19665588

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

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

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

Optimal design of studies of influenza transmission in households. II: comparison between cohort and case-ascertained studies.

PubMed

Klick, B; Nishiura, H; Leung, G M; Cowling, B J

2014-04-01

Both case-ascertained household studies, in which households are recruited after an 'index case' is identified, and household cohort studies, where a household is enrolled before the start of the epidemic, may be used to test and estimate the protective effect of interventions used to prevent influenza transmission. A simulation approach parameterized with empirical data from household studies was used to evaluate and compare the statistical power of four study designs: a cohort study with routine virological testing of household contacts of infected index case, a cohort study where only household contacts with acute respiratory illness (ARI) are sampled for virological testing, a case-ascertained study with routine virological testing of household contacts, and a case-ascertained study where only household contacts with ARI are sampled for virological testing. We found that a case-ascertained study with ARI-triggered testing would be the most powerful design while a cohort design only testing household contacts with ARI was the least powerful. Sensitivity analysis demonstrated that these conclusions varied by model parameters including the serial interval and the risk of influenza virus infection from outside the household.

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

Design and Methods of the Mood Disorder Cohort Research Consortium (MDCRC) Study

PubMed Central

Cho, Chul-Hyun; Ahn, Yong-Min; Kim, Se Joo; Ha, Tae Hyun; Jeon, Hong Jin; Cha, Boseok; Moon, Eunsoo; Park, Dong Yeon; Baek, Ji Hyun; Kang, Hee-Ju; Ryu, Vin; An, Hyonggin

2017-01-01

The Mood Disorder Cohort Research Consortium (MDCRC) study is designed as a naturalistic observational prospective cohort study for early-onset mood disorders (major depressive disorders, bipolar disorders type 1 and 2) in South Korea. The study subjects consist of two populations: 1) patients with mood disorders under 25 years old and 2) patients with mood disorders within 2 years of treatment under 35 years old. After successful screening, the subjects are evaluated using baseline assessments and serial follow-up assessments at 3-month intervals. Between the follow-up assessments, subjects are dictated to check their own daily mood status before bedtime using the eMood chart application or a paper mood diary. At the regular visits every 3 months, inter-visit assessments are evaluated based on daily mood charts and interviews with patients. In addition to the daily mood chart, sleep quality, inter-visit major and minor mood episodes, stressful life events, and medical usage pattern with medical expenses are also assessed. Genomic DNA from blood is obtained for genomic analyses. From the MDCRC study, the clinical course, prognosis, and related factors of early-onset mood disorders can be clarified. The MDCRC is also able to facilitate translational research for mood disorders and provide a resource for the convergence study of mood disorders. PMID:28096882

Investing in Prospective Cohorts for Etiologic Study of Occupational Exposures

PubMed Central

Blair, A.; Hines, C.J.; Thomas, K.W.; Alavanja, M.C.R.; Beane Freeman, L.E.; Hoppin, J.A.; Kamel, F.; Lynch, C.F.; Lubin, J.H.; Silverman, D.T.; Whelan, E.; Zahm, S. H.; Sandler, D. P.

2015-01-01

Prospective cohorts have played a major role in understanding the contribution of diet, physical activity, medical conditions, and genes to the development of many diseases, but have not been widely used for occupational exposures. Studies in agriculture are an exception. We draw upon our experience using this design to study agricultural workers to identify conditions that might foster use of prospective cohorts to study other occupational settings. Prospective cohort studies are perceived by many as the strongest epidemiologic design. It allows updating of information on exposure and other factors, collection of biologic samples before disease diagnosis for biomarker studies, assessment of effect modification by genes, lifestyle, and other occupational exposures, and evaluation of a wide range of health outcomes. Increased use of prospective cohorts would be beneficial in identifying hazardous exposures in the workplace. Occupational epidemiologists should seek opportunities to initiate prospective cohorts to investigate high priority, occupational exposures. PMID:25603935

75 FR 27785 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

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76 FR 7852 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-11

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... concerning the final effect of the HHS decision to designate a class of employees from Simonds Saw and Steel...

75 FR 27784 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... concerning the final effect of the decision to designate a class of employees from the Nevada Test Site as an...

An EVS Clicker Based Hybrid Assessment to Engage Students with Marking Criteria

ERIC Educational Resources Information Center

Bennett, Steve; Barker, Trevor; Lilley, Mariana

2014-01-01

Over 4 iterations of a large course (>180 students) in introductory emedia design in a first year computer science course we have seen a year on year improvement. We believe this is due to the use of EVS clickers for feed-forward assessment: that is to say a method of getting the whole class to evaluate previous cohorts' submissions in public…

Cross-Sectional and Longitudinal Risk Factors for Falls, Fear of Falling, and Falls Efficacy in a Cohort of Middle-Aged African Americans

ERIC Educational Resources Information Center

Anderson, Elena M.; Wolinsky, Fredric D.; Miller, J. Phillip; Wilson, Margaret-Mary G.; Malmstrom, Theodore K.; Miller, Douglas K.

2006-01-01

Purpose: The purpose of this study is to cross-sectionally and longitudinally identify risk factors for falls, fear of falling, and falls efficacy in late-middle-aged African Americans. Design and Methods: We performed in-home assessments on a probability sample of 998 African Americans and conducted two annual follow-up interviews. Multiple…

Predictors and Pathways of Language and Motor Development in Four Prospective Cohorts of Young Children in Ghana, Malawi, and Burkina Faso

ERIC Educational Resources Information Center

Prado, Elizabeth L.; Abbeddou, Souheila; Adu-Afarwuah, Seth; Arimond, Mary; Ashorn, Per; Ashorn, Ulla; Bendabenda, Jaden; Brown, Kenneth H.; Hess, Sonja Y.; Kortekangas, Emma; Lartey, Anna; Maleta, Kenneth; Oaks, Brietta M.; Ocansey, Eugenia; Okronipa, Harriet; Ouédraogo, Jean Bosco; Pulakka, Anna; Somé, Jérôme W.; Stewart, Christine P.; Stewart, Robert C.; Vosti, Stephen A.; Yakes Jimenez, Elizabeth; Dewey, Kathryn G.

2017-01-01

Background: Previous reviews have identified 44 risk factors for poor early child development (ECD) in low- and middle-income countries. Further understanding of their relative influence and pathways is needed to inform the design of interventions targeting ECD. Methods: We conducted path analyses of factors associated with 18-month language and…

Changes in Cancer Incidence Patterns among a Northeastern American Indian Population: 1955-1969 versus 1990-2004

ERIC Educational Resources Information Center

Mahoney, Martin C.; Va, Puthiery; Stevens, Adrian; Kahn, Amy R.; Michalek, Arthur M.

2009-01-01

Purpose: This manuscript examines shifts in patterns of cancer incidence among the Seneca Nation of Indians (SNI) for the interval 1955-1969 compared to 1990-2004. Methods: A retrospective cohort design was used to examine cancer incidence among the SNI during 2 time intervals: 1955-1969 and 1990-2004. Person-years at risk were multiplied by…

Examination of the Philadelphia Geriatric Morale Scale as a Subjective Quality-of-Life Measure in Elderly Hong Kong Chinese

ERIC Educational Resources Information Center

Wong, Eric; Woo, Jean; Hui, Elsie; Ho, Suzanne C.

2004-01-01

Purpose: We examine the psychometric properties of the Philadelphia Geriatric Morale Scale (PGMS) in an elderly Chinese population in Hong Kong. Design and Methods: The study consisted of two cohorts: (a) 759 participants aged 70 years and older living in the community who were recruited as part of a territory-wide health survey and interviewed in…

Racial Differences in Hospice Use and In-Hospital Death among Medicare and Medicaid Dual-Eligible Nursing Home Residents

ERIC Educational Resources Information Center

Kwak, Jung; Haley, William E.; Chiriboga, David A.

2008-01-01

Purpose: We investigated the role of race in predicting the likelihood of using hospice and dying in a hospital among dual-eligible (Medicare and Medicaid) nursing home residents. Design and Methods: This follow-back cohort study examined factors associated with hospice use and in-hospital death among non-Hispanic Black and non-Hispanic White…

Student-Centered Pedagogy and Real-World Research: Using Documents as Sources of Data in Teaching Social Science Skills and Methods

ERIC Educational Resources Information Center

Peyrefitte, Magali; Lazar, Gillian

2018-01-01

This teaching note describes the design and implementation of an activity in a 90-minute teaching session that was developed to introduce a diverse cohort of first-year criminology and sociology students to the use of documents as sources of data. This approach was contextualized in real-world research through scaffolded, student-centered tasks…

Next-generation, personalised, model-based critical care medicine: a state-of-the art review of in silico virtual patient models, methods, and cohorts, and how to validation them.

PubMed

Chase, J Geoffrey; Preiser, Jean-Charles; Dickson, Jennifer L; Pironet, Antoine; Chiew, Yeong Shiong; Pretty, Christopher G; Shaw, Geoffrey M; Benyo, Balazs; Moeller, Knut; Safaei, Soroush; Tawhai, Merryn; Hunter, Peter; Desaive, Thomas

2018-02-20

Critical care, like many healthcare areas, is under a dual assault from significantly increasing demographic and economic pressures. Intensive care unit (ICU) patients are highly variable in response to treatment, and increasingly aging populations mean ICUs are under increasing demand and their cohorts are increasingly ill. Equally, patient expectations are growing, while the economic ability to deliver care to all is declining. Better, more productive care is thus the big challenge. One means to that end is personalised care designed to manage the significant inter- and intra-patient variability that makes the ICU patient difficult. Thus, moving from current "one size fits all" protocolised care to adaptive, model-based "one method fits all" personalised care could deliver the required step change in the quality, and simultaneously the productivity and cost, of care. Computer models of human physiology are a unique tool to personalise care, as they can couple clinical data with mathematical methods to create subject-specific models and virtual patients to design new, personalised and more optimal protocols, as well as to guide care in real-time. They rely on identifying time varying patient-specific parameters in the model that capture inter- and intra-patient variability, the difference between patients and the evolution of patient condition. Properly validated, virtual patients represent the real patients, and can be used in silico to test different protocols or interventions, or in real-time to guide care. Hence, the underlying models and methods create the foundation for next generation care, as well as a tool for safely and rapidly developing personalised treatment protocols over large virtual cohorts using virtual trials. This review examines the models and methods used to create virtual patients. Specifically, it presents the models types and structures used and the data required. It then covers how to validate the resulting virtual patients and trials, and how these virtual trials can help design and optimise clinical trial. Links between these models and higher order, more complex physiome models are also discussed. In each section, it explores the progress reported up to date, especially on core ICU therapies in glycemic, circulatory and mechanical ventilation management, where high cost and frequency of occurrence provide a significant opportunity for model-based methods to have measurable clinical and economic impact. The outcomes are readily generalised to other areas of medical care.

N-of-1-pathways MixEnrich: advancing precision medicine via single-subject analysis in discovering dynamic changes of transcriptomes.

PubMed

Li, Qike; Schissler, A Grant; Gardeux, Vincent; Achour, Ikbel; Kenost, Colleen; Berghout, Joanne; Li, Haiquan; Zhang, Hao Helen; Lussier, Yves A

2017-05-24

Transcriptome analytic tools are commonly used across patient cohorts to develop drugs and predict clinical outcomes. However, as precision medicine pursues more accurate and individualized treatment decisions, these methods are not designed to address single-patient transcriptome analyses. We previously developed and validated the N-of-1-pathways framework using two methods, Wilcoxon and Mahalanobis Distance (MD), for personal transcriptome analysis derived from a pair of samples of a single patient. Although, both methods uncover concordantly dysregulated pathways, they are not designed to detect dysregulated pathways with up- and down-regulated genes (bidirectional dysregulation) that are ubiquitous in biological systems. We developed N-of-1-pathways MixEnrich, a mixture model followed by a gene set enrichment test, to uncover bidirectional and concordantly dysregulated pathways one patient at a time. We assess its accuracy in a comprehensive simulation study and in a RNA-Seq data analysis of head and neck squamous cell carcinomas (HNSCCs). In presence of bidirectionally dysregulated genes in the pathway or in presence of high background noise, MixEnrich substantially outperforms previous single-subject transcriptome analysis methods, both in the simulation study and the HNSCCs data analysis (ROC Curves; higher true positive rates; lower false positive rates). Bidirectional and concordant dysregulated pathways uncovered by MixEnrich in each patient largely overlapped with the quasi-gold standard compared to other single-subject and cohort-based transcriptome analyses. The greater performance of MixEnrich presents an advantage over previous methods to meet the promise of providing accurate personal transcriptome analysis to support precision medicine at point of care.

Design and process of the EMA Cohort Study: the value of antenatal education in childbirth and breastfeeding

PubMed Central

Paz-Pascual, Carmen; Pinedo, Isabel Artieta; Grandes, Gonzalo; de Gamboa, Gurutze Remiro Fernandez; Hermosilla, Itziar Odriozola; de la Hera, Amaia Bacigalupe; Gordon, Janire Payo; Garcia, Guadalupe Manzano; de Pedro, Magdalena Ureta

2008-01-01

Background Antenatal education (AE) started more than 30 years ago with the purpose of decreasing pain during childbirth. Epidural anaesthesia has achieved this objective, and the value of AE is therefore currently questioned. This article describes the protocol and process of a study designed to assess AE results today. Methods/Design A prospective study was designed in which a cohort of 616 nulliparous pregnant women attending midwife offices of the Basque Health Service were followed for 13 months. Three exposure groups were considered based on the number of AE sessions attended: (a) women attending no session, (b) women attending 1 to 4, and (c) women attending 5 or more sessions. Sociodemographic, personality, and outcome variables related to childbirth and breastfeeding were measured. It was expected 40% of pregnant women not to have participated in any AE session. However, 93% had attended at least one session. This low exposure variability decreased statistical power of the study as compared to the initially planned power. Despite this, there was a greater than 80% power for detecting as significant differences between exposure groups of, for instance, 10% in continuation of breastfeeding at one and a half months and in visits for false labour. Women attending more sessions were seen to have a mean higher age and educational level, and to belong to a higher socioeconomic group (p < 0.01). Follow-up was completed in 99% of participants. Discussion Adequate prior estimation of variability in the exposure under study is essential for designing cohort studies. Sociodemographic characteristics may play a confounding role in studies assessing AE and should be controlled in design and analyses. Quality control during the study process and continued collaboration from both public system midwives and eligible pregnant women resulted in a negligible loss rate. PMID:18435856

Statins and Risk of Lower Limb Revision Surgery: The Influence of Differences in Study Design Using Electronic Health Records From the United Kingdom and Denmark

PubMed Central

Lalmohamed, Arief; van Staa, Tjeerd P.; Vestergaard, Peter; Leufkens, Hubertus G. M.; de Boer, Anthonius; Emans, Pieter; Cooper, Cyrus; de Vries, Frank

2016-01-01

Abstract Previous observational studies on statins have shown variable results based on the methodology used. Our objective was to study the association between statins and orthopedic implant failure and to explore the influence of methodological differences in study design. Our study base consisted of patients with a primary total joint replacement in Denmark and the United Kingdom (n = 189,286; 1987–2012). We used 4 study designs: 1) case-control (each patient with revision surgery matched to 4 controls), 2) time-dependent cohort (postoperative statin use as a time-varying exposure variable), 3) immortal time cohort (misclassifying the time postoperatively before statin use), and 4) time-exclusion cohort (excluding the time postoperatively before statin use). Cox proportional hazards models and logistic regression were used to estimate incidence rate ratios. In the time-dependent cohort design, statin use was associated with a decreased risk of revision surgery (adjusted incidence rate ratio (IRR) = 0.90, 95% confidence interval (CI): 0.85, 0.96), which was similar to our case-control results (IRR = 0.87, 95% CI: 0.81, 0.93). In contrast, both time-fixed cohort designs yielded substantially lower risk estimates (IRR = 0.36 (95% CI: 0.34, 0.38) and IRR = 0.65 (95% CI: 0.63, 0.68), respectively). We discourage the use of time-fixed cohort studies, which may falsely suggest protective effects. The simple choice of how to classify exposure can substantially change results from biologically plausible to implausible. PMID:27317693

Prospective cohort studies of newly marketed medications: using covariate data to inform the design of large-scale studies.

PubMed

Franklin, Jessica M; Rassen, Jeremy A; Bartels, Dorothee B; Schneeweiss, Sebastian

2014-01-01

Nonrandomized safety and effectiveness studies are often initiated immediately after the approval of a new medication, but patients prescribed the new medication during this period may be substantially different from those receiving an existing comparator treatment. Restricting the study to comparable patients after data have been collected is inefficient in prospective studies with primary collection of outcomes. We discuss design and methods for evaluating covariate data to assess the comparability of treatment groups, identify patient subgroups that are not comparable, and decide when to transition to a large-scale comparative study. We demonstrate methods in an example study comparing Cox-2 inhibitors during their postmarketing period (1999-2005) with nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). Graphical checks of propensity score distributions in each treatment group showed substantial problems with overlap in the initial cohorts. In the first half of 1999, >40% of patients were in the region of nonoverlap on the propensity score, and across the study period this fraction never dropped below 10% (the a priori decision threshold for transitioning to the large-scale study). After restricting to patients with no prior NSAID use, <1% of patients were in the region of nonoverlap, indicating that a large-scale study could be initiated in this subgroup and few patients would need to be trimmed from analysis. A sequential study design that uses pilot data to evaluate treatment selection can guide the efficient design of large-scale outcome studies with primary data collection by focusing on comparable patients.

Newly designed 11-gene panel reveals first case of hereditary amyloidosis captured by massive parallel sequencing.

PubMed

Chyra Kufova, Zuzana; Sevcikova, Tereza; Januska, Jaroslav; Vojta, Petr; Boday, Arpad; Vanickova, Pavla; Filipova, Jana; Growkova, Katerina; Jelinek, Tomas; Hajduch, Marian; Hajek, Roman

2018-02-17

Amyloidosis is caused by deposition of abnormal protein fibrils, leading to damage of organ function. Hereditary amyloidosis represents a monogenic disease caused by germline mutations in 11 amyloidogenic precursor protein genes. One of the important but non-specific symptoms of amyloidosis is hypertrophic cardiomyopathy. Diagnostics of hereditary amyloidosis is complicated and the real cause can remain overlooked. We aimed to design hereditary amyloidosis gene panel and to introduce new next-generation sequencing (NGS) approach to investigate hereditary amyloidosis in a cohort of patients with hypertrophic cardiomyopathy of unknown significance. Design of target enrichment DNA library preparation using Haloplex Custom Kit containing 11 amyloidogenic genes was followed by MiSeq Illumina sequencing and bioinformatics identification of germline variants using tool VarScan in a cohort of 40 patients. We present design of NGS panel for 11 genes ( TTR , FGA , APOA1 , APOA2 , LYZ , GSN , CST3 , PRNP , APP , B2M , ITM2B ) connected to various forms of amyloidosis. We detected one mutation, which is responsible for hereditary amyloidosis. Some other single nucleotide variants are so far undescribed or rare variants or represent common polymorphisms in European population. We report one positive case of hereditary amyloidosis in a cohort of patients with hypertrophic cardiomyopathy of unknown significance and set up first panel for NGS in hereditary amyloidosis. This work may facilitate successful implementation of the NGS method by other researchers or clinicians and may improve the diagnostic process after validation. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Block Constraints in Age-Period-Cohort Models with Unequal-Width Intervals

ERIC Educational Resources Information Center

Luo, Liying; Hodges, James S.

2016-01-01

Age-period-cohort (APC) models are designed to estimate the independent effects of age, time periods, and cohort membership. However, APC models suffer from an identification problem: There are no unique estimates of the independent effects that fit the data best because of the exact linear dependency among age, period, and cohort. Among methods…

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

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

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.

Determinants of cardiovascular disease and other non-communicable diseases in Central and Eastern Europe: Rationale and design of the HAPIEE study

PubMed Central

Peasey, Anne; Bobak, Martin; Kubinova, Ruzena; Malyutina, Sofia; Pajak, Andrzej; Tamosiunas, Abdonas; Pikhart, Hynek; Nicholson, Amanda; Marmot, Michael

2006-01-01

Background Over the last five decades, a wide gap in mortality opened between western and eastern Europe; this gap increased further after the dramatic fluctuations in mortality in the former Soviet Union (FSU) in the 1990s. Recent rapid increases in mortality among lower socioeconomic groups in eastern Europe suggests that socioeconomic factors are powerful determinants of mortality in these populations but the more proximal factors linking the social conditions with health remain unclear. The HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe) study is a prospective cohort study designed to investigate the effect of classical and non-conventional risk factors and social and psychosocial factors on cardiovascular and other non-communicable diseases in eastern Europe and the FSU. The main hypotheses of the HAPIEE study relate to the role of alcohol, nutrition and psychosocial factors. Methods and design The HAPIEE study comprises four cohorts in Russia, Poland, the Czech Republic and Lithuania; each consists of a random sample of men and women aged 45–69 years old at baseline, stratified by gender and 5 year age groups, and selected from population registers. The total planned sample size is 36,500 individuals. Baseline information from the Czech Republic, Russia and Poland was collected in 2002–2005 and includes data on health, lifestyle, diet (food frequency), socioeconomic circumstances and psychosocial factors. A short examination included measurement of anthropometric parameters, blood pressure, lung function and cognitive function, and a fasting venous blood sample. Re-examination of the cohorts in 2006–2008 focuses on healthy ageing and economic well-being using face-to-face computer assisted personal interviews. Recruitment of the Lithuanian cohort is ongoing, with baseline and re-examination data being collected simultaneously. All cohorts are being followed up for mortality and non-fatal cardiovascular events. Discussion The HAPIEE study will provide important new insights into social, behavioural and biological factors influencing mortality and cardiovascular risk in the region. PMID:17049075

The All Our Babies pregnancy cohort: design, methods, and participant characteristics.

PubMed

McDonald, Sheila W; Lyon, Andrew W; Benzies, Karen M; McNeil, Deborah A; Lye, Stephen J; Dolan, Siobhan M; Pennell, Craig E; Bocking, Alan D; Tough, Suzanne C

2013-01-01

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. 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. 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. 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.

Effects of imperfect test sensitivity and specificity on observational studies of influenza vaccine effectiveness.

PubMed

Jackson, Michael L; Rothman, Kenneth J

2015-03-10

The recently developed test-negative design is now standard for observational studies of influenza vaccine effectiveness (VE). It is unclear how influenza test misclassification biases test-negative VE estimates relative to VE estimates from traditional cohort or case-control studies. We simulated populations whose members may develop acute respiratory illness (ARI) due to influenza and to non-influenza pathogens. In these simulations, vaccination reduces the risk of influenza but not of non-influenza ARI. Influenza test sensitivity and specificity, risks of influenza and non-influenza ARI, and VE were varied across the simulations. In each simulation, we estimated influenza VE using a cohort design, a case-control design, and a test-negative design. In the absence of influenza test misclassification, all three designs accurately estimated influenza VE. In the presence of misclassification, all three designs underestimated VE. Bias in VE estimates was slightly greater in the test-negative design than in cohort or case-control designs. Assuming the use of highly sensitive and specific reverse-transcriptase polymerase chain reaction tests for influenza, bias in the test-negative studies was trivial across a wide range of realistic values for VE. Although influenza test misclassification causes more bias in test-negative studies than in traditional cohort or case-control studies, the difference is trivial for realistic combinations of attack rates, test sensitivity/specificity, and VE. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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

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

Comparative effectiveness of colony-stimulating factors in febrile neutropenia prophylaxis: how results are affected by research design.

PubMed

Henk, Henry J; Li, Xiaoyan; Becker, Laura K; Xu, Hairong; Gong, Qi; Deeter, Robert G; Barron, Richard L

2015-01-01

To examine the impact of research design on results in two published comparative effectiveness studies. Guidelines for comparative effectiveness research have recommended incorporating disease process in study design. Based on the recommendations, we develop a checklist of considerations and apply the checklist in review of two published studies on comparative effectiveness of colony-stimulating factors. Both studies used similar administrative claims data, but different methods, which resulted in directionally different estimates. Major design differences between the two studies include: whether the timing of intervention in disease process was identified and whether study cohort and outcome assessment period were defined based on this temporal relationship. Disease process and timing of intervention should be incorporated into the design of comparative effectiveness studies.

Design and methods in a survey of living conditions in the Arctic - the SLiCA study.

PubMed

Eliassen, Bent-Martin; Melhus, Marita; Kruse, Jack; Poppel, Birger; Broderstad, Ann Ragnhild

2012-03-19

The main objective of this study is to describe the methods and design of the survey of living conditions in the Arctic (SLiCA), relevant participation rates and the distribution of participants, as applicable to the survey data in Alaska, Greenland and Norway. This article briefly addresses possible selection bias in the data and also the ways to tackle it in future studies. Population-based cross-sectional survey. Indigenous individuals aged 16 years and older, living in Greenland, Alaska and in traditional settlement areas in Norway, were invited to participate. Random sampling methods were applied in Alaska and Greenland, while non-probability sampling methods were applied in Norway. Data were collected in 3 periods: in Alaska, from January 2002 to February 2003; in Greenland, from December 2003 to August 2006; and in Norway, in 2003 and from June 2006 to June 2008. The principal method in SLiCA was standardised face-to-face interviews using a questionnaire. A total of 663, 1,197 and 445 individuals were interviewed in Alaska, Greenland and Norway, respectively. Very high overall participation rates of 83% were obtained in Greenland and Alaska, while a more conventional rate of 57% was achieved in Norway. A predominance of female respondents was obtained in Alaska. Overall, the Sami cohort is older than the cohorts from Greenland and Alaska. Preliminary assessments suggest that selection bias in the Sami sample is plausible but not a major threat. Few or no threats to validity are detected in the data from Alaska and Greenland. Despite different sampling and recruitment methods, and sociocultural differences, a unique database has been generated, which shall be used to explore relationships between health and other living conditions variables.

Early Performance of Accountable Care Organizations in Medicare

PubMed Central

McWilliams, J. Michael; Hatfield, Laura A.; Chernew, Michael E.; Landon, Bruce E.; Schwartz, Aaron L.

2016-01-01

BACKGROUND In the Medicare Shared Savings Program (MSSP), accountable care organizations (ACOs) have financial incentives to lower spending and improve quality. We used quasi-experimental methods to assess the early performance of MSSP ACOs. METHODS Using Medicare claims from 2009 through 2013 and a difference-in-differences design, we compared changes in spending and in performance on quality measures from before the start of ACO contracts to after the start of the contracts between beneficiaries served by the 220 ACOs entering the MSSP in mid-2012 (2012 ACO cohort) or January 2013 (2013 ACO cohort) and those served by non-ACO providers (control group), with adjustment for geographic area and beneficiary characteristics. We analyzed the 2012 and 2013 ACO cohorts separately because entry time could reflect the capacity of an ACO to achieve savings. We compared ACO savings according to organizational structure, baseline spending, and concurrent ACO contracting with commercial insurers. RESULTS Adjusted Medicare spending and spending trends were similar in the ACO cohorts and the control group during the precontract period. In 2013, the differential change (i.e., the between-group difference in the change from the precontract period) in total adjusted annual spending was −$144 per beneficiary in the 2012 ACO cohort as compared with the control group (P = 0.02), consistent with a 1.4% savings, but only −$3 per beneficiary in the 2013 ACO cohort as compared with the control group (P = 0.96). Estimated savings were consistently greater in independent primary care groups than in hospital-integrated groups among 2012 and 2013 MSSP entrants (P = 0.005 for interaction). MSSP contracts were associated with improved performance on some quality measures and unchanged performance on others. CONCLUSIONS The first full year of MSSP contracts was associated with early reductions in Medicare spending among 2012 entrants but not among 2013 entrants. Savings were greater in independent primary care groups than in hospital-integrated groups. PMID:27075832

Blood manganese as an exposure biomarker: State of the evidence

PubMed Central

Baker, Marissa G.; Simpson, Christopher D.; Stover, Bert; Sheppard, Lianne; Checkoway, Harvey; Racette, Brad A.; Seixas, Noah S.

2014-01-01

Despite evidence of adverse health effects resulting from exposure to manganese (Mn), biomarkers of exposure are poorly understood. To enhance understanding, mean blood Mn (MnB) and mean air Mn (MnA) were extracted from 63 exposure groups in 24 published papers, and the relationship was modeled using segmented regression. On a log/log scale, a positive association between MnA and MnB was observed among studies reporting MnA concentrations above about 10 μg/m3, although interpretation is limited by largely cross-sectional data, study design variability, and differences in exposure monitoring methods. Based on the results of the segmented regression, we hypothesize that below the concentration of about 10 μg/m3, Mn in the body is dominated by dietary Mn, and additional inhaled Mn only causes negligible changes in Mn levels unless the inhaled amount is substantial. However, stronger study designs are required to account for temporal characteristics of the MnA to MnB relationships which reflect the underlying physiology and toxicokinetics of Mn uptake and distribution. Thus, we present an inception cohort study design we have conducted among apprentice welders, and the analytical strengths this study design offers. To determine if blood could be a useful biomarker for Mn to be utilized by industrial hygienists in general industry requires additional time-specific analyses, which our inception cohort study design will allow. PMID:24579750

Designing Reliable Cohorts of Cardiac Patients across MIMIC and eICU

PubMed Central

Chronaki, Catherine; Shahin, Abdullah; Mark, Roger

2016-01-01

The design of the patient cohort is an essential and fundamental part of any clinical patient study. Knowledge of the Electronic Health Records, underlying Database Management System, and the relevant clinical workflows are central to an effective cohort design. However, with technical, semantic, and organizational interoperability limitations, the database queries associated with a patient cohort may need to be reconfigured in every participating site. i2b2 and SHRINE advance the notion of patient cohorts as first class objects to be shared, aggregated, and recruited for research purposes across clinical sites. This paper reports on initial efforts to assess the integration of Medical Information Mart for Intensive Care (MIMIC) and Philips eICU, two large-scale anonymized intensive care unit (ICU) databases, using standard terminologies, i.e. LOINC, ICD9-CM and SNOMED-CT. Focus of this work is lab and microbiology observations and key demographics for patients with a primary cardiovascular ICD9-CM diagnosis. Results and discussion reflecting on reference core terminology standards, offer insights on efforts to combine detailed intensive care data from multiple ICUs worldwide. PMID:27774488

Risk factors associated with asbestos-related diseases: a community-based case–control study

PubMed Central

2013-01-01

Background Asbestos is a first level carcinogen. However, few epidemiological studies analyse the risk and protective factors associated with asbestos-related diseases and follow up these conditions in the general population. Pleural mesothelioma, caused by inhalation of asbestos fibres at work, at home or in the environment, is the most representative asbestos-related disease. The objectives of this study are to analyse the risk and protective factors associated with asbestos-related diseases and to investigate the incidence of new clinical manifestations in patients already diagnosed with some form of ARD. Methods/Design We have designed a matched case–control study with follow up of both cohorts from a population of a health district of the Barcelona province that has been exposed to asbestos for a period of 90 years. Discussion A better understanding of asbestos-related diseases should improve i) the clinical and epidemiological follow up of patients with this condition; ii) the design of new treatment strategies; iii) and the development of preventive activities. At the end of the study, the two cohorts created in this study (affected cases and healthy controls) will constitute the basis for future research. PMID:23915043

The Nicaraguan Pediatric Dengue Cohort Study: Study Design, Methods, Use of Information Technology, and Extension to Other Infectious Diseases

PubMed Central

Kuan, Guillermina; Gordon, Aubree; Avilés, William; Ortega, Oscar; Hammond, Samantha N.; Elizondo, Douglas; Nuñez, Andrea; Coloma, Josefina; Balmaseda, Angel

2009-01-01

Dengue is a mosquito-borne viral disease that is a major public health problem worldwide. In 2004, the Pediatric Dengue Cohort Study was established in Managua, Nicaragua, to study the natural history and transmission of dengue in children. Here, the authors describe the study design, methods, and results from 2004 to 2008. Initially, 3,721 children 2–9 years of age were recruited through door-to-door visits. Each year, new children aged 2 years are enrolled in the study to maintain the age structure. Children are provided with medical care through the study, and data from each medical visit are recorded on systematic study forms. All participants presenting with suspected dengue or undifferentiated fever are tested for dengue by virologic, serologic, and molecular biologic assays. Yearly blood samples are collected to detect inapparent dengue virus infections. Numerous information and communications technologies are used to manage study data, track samples, and maintain quality control, including personal data assistants, barcodes, global information systems, and fingerprint scans. Close collaboration with the Nicaraguan Ministry of Health and use of almost entirely local staff are essential components for success. This study is providing critical data on the epidemiology and transmission of dengue in the Americas needed for future vaccine trials. PMID:19435864

Prospective Dutch colorectal cancer cohort: an infrastructure for long-term observational, prognostic, predictive and (randomized) intervention research.

PubMed

Burbach, J P M; Kurk, S A; Coebergh van den Braak, R R J; Dik, V K; May, A M; Meijer, G A; Punt, C J A; Vink, G R; Los, M; Hoogerbrugge, N; Huijgens, P C; Ijzermans, J N M; Kuipers, E J; de Noo, M E; Pennings, J P; van der Velden, A M T; Verhoef, C; Siersema, P D; van Oijen, M G H; Verkooijen, H M; Koopman, M

2016-11-01

Systematic evaluation and validation of new prognostic and predictive markers, technologies and interventions for colorectal cancer (CRC) is crucial for optimizing patients' outcomes. With only 5-15% of patients participating in clinical trials, generalizability of results is poor. Moreover, current trials often lack the capacity for post-hoc subgroup analyses. For this purpose, a large observational cohort study, serving as a multiple trial and biobanking facility, was set up by the Dutch Colorectal Cancer Group (DCCG). The Prospective Dutch ColoRectal Cancer cohort is a prospective multidisciplinary nationwide observational cohort study in the Netherlands (yearly CRC incidence of 15 500). All CRC patients (stage I-IV) are eligible for inclusion, and longitudinal clinical data are registered. Patients give separate consent for the collection of blood and tumor tissue, filling out questionnaires, and broad randomization for studies according to the innovative cohort multiple randomized controlled trial design (cmRCT), serving as an alternative study design for the classic RCT. Objectives of the study include: 1) systematically collected long-term clinical data, patient-reported outcomes and biomaterials from daily CRC practice; and 2) to facilitate future basic, translational and clinical research including interventional and cost-effectiveness studies for both national and international research groups with short inclusion periods, even for studies with stringent inclusion criteria. Seven months after initiation 650 patients have been enrolled, eight centers participate, 15 centers await IRB approval and nine embedded cohort- or cmRCT-designed studies are currently recruiting patients. This cohort provides a unique multidisciplinary data, biobank, and patient-reported outcomes collection initiative, serving as an infrastructure for various kinds of research aiming to improve treatment outcomes in CRC patients. This comprehensive design may serve as an example for other tumor types.

User-only design to assess drug effectiveness in clinical practice: application to bisphosphonates and secondary prevention of fractures.

PubMed

Corrao, Giovanni; Ghirardi, Arianna; Segafredo, Giulia; Zambon, Antonella; Della Vedova, Gianluca; Lapi, Francesco; Cipriani, Francesco; Caputi, Achille; Vaccheri, Alberto; Gregori, Dario; Gesuita, Rosaria; Vestri, Annarita; Staniscia, Tommaso; Mazzaglia, Giampiero; Di Bari, Mauro

2014-08-01

Different strategies applicable to control for confounding by indication in observational studies were compared in a large population-based study regarding the effect of bisphosphonates (BPs) for secondary prevention of fractures. The cohort was drawn from healthcare utilization databases of 13 Italian territorial units. Patients aged 55 years or more who were hospitalized for fracture during 2003-2005 entered into the cohort. A nested case-control design was used to compare BPs use in cohort members who did (cases) and who did not experience (controls) a new fracture until 2007 (outcome). Three designs were employed: conventional-matching (D1 ), propensity score-matching (D2 ), and user-only (D3 ) designs. They differed for (i) cohort composition, restricted to patients who received BPs straight after cohort entry (D3 ); (ii) using propensity score for case-control matching (D2 ); and (iii) compared groups of BPs users versus no users (D1 and D2 ) and long-term versus short-term users (D3 ). Bisphosphonate users had odds ratios (95% confidence interval) of 1.20 (1.01 to 1.44) and 0.95 (0.74 to 1.24) by applying D1 and D2 designs, respectively. Statistical evidence that long-term BPs use protects the outcome onset with respect to short-term use was observed for user-only design (D3 ) being the corresponding odds ratio (95% confidence interval) 0.64 (0.44 to 0.93). User-only design yielded closer results to those seen in RCTs. This approach is one possible strategy to account for confounding by indication. Copyright © 2014 John Wiley & Sons, Ltd.

Are quantitative trait-dependent sampling designs cost-effective for analysis of rare and common variants?

PubMed

Yilmaz, Yildiz E; Bull, Shelley B

2011-11-29

Use of trait-dependent sampling designs in whole-genome association studies of sequence data can reduce total sequencing costs with modest losses of statistical efficiency. In a quantitative trait (QT) analysis of data from the Genetic Analysis Workshop 17 mini-exome for unrelated individuals in the Asian subpopulation, we investigate alternative designs that sequence only 50% of the entire cohort. In addition to a simple random sampling design, we consider extreme-phenotype designs that are of increasing interest in genetic association analysis of QTs, especially in studies concerned with the detection of rare genetic variants. We also evaluate a novel sampling design in which all individuals have a nonzero probability of being selected into the sample but in which individuals with extreme phenotypes have a proportionately larger probability. We take differential sampling of individuals with informative trait values into account by inverse probability weighting using standard survey methods which thus generalizes to the source population. In replicate 1 data, we applied the designs in association analysis of Q1 with both rare and common variants in the FLT1 gene, based on knowledge of the generating model. Using all 200 replicate data sets, we similarly analyzed Q1 and Q4 (which is known to be free of association with FLT1) to evaluate relative efficiency, type I error, and power. Simulation study results suggest that the QT-dependent selection designs generally yield greater than 50% relative efficiency compared to using the entire cohort, implying cost-effectiveness of 50% sample selection and worthwhile reduction of sequencing costs.

Immortal time bias in pharmaco-epidemiology.

PubMed

Suissa, Samy

2008-02-15

Immortal time is a span of cohort follow-up during which, because of exposure definition, the outcome under study could not occur. Bias from immortal time was first identified in the 1970s in epidemiology in the context of cohort studies of the survival benefit of heart transplantation. It recently resurfaced in pharmaco-epidemiology, with several observational studies reporting that various medications can be extremely effective at reducing morbidity and mortality. These studies, while using different cohort designs, all involved some form of immortal time and the corresponding bias. In this paper, the author describes various cohort study designs leading to this bias, quantifies its magnitude under different survival distributions, and illustrates it by using data from a cohort of lung cancer patients. The author shows that for time-based, event-based, and exposure-based cohort definitions, the bias in the rate ratio resulting from misclassified or excluded immortal time increases proportionately to the duration of immortal time. The bias is more pronounced with a decreasing hazard function for the outcome event, as illustrated with the Weibull distribution compared with a constant hazard from the exponential distribution. In conclusion, observational studies of drug benefit in which computerized databases are used must be designed and analyzed properly to avoid immortal time bias.

Feasibility of Conducting a Longitudinal, Transnational Study of Filipino Migrants to the United States: A Dual-Cohort Design

PubMed Central

Gee, Gilbert C.; de Castro, A.B.; Wang, May C.; Crespi, Catherine M.; Morey, Brittany N.; Fujishiro, Kaori

2015-01-01

Most studies of immigrant health are cross-sectional and fail to collect information prior to migration, leading to potential bias and confounding. The present pilot study examines the feasibility of studying migrants prospectively, with baseline data collected before migration. The study followed two cohorts of Filipinos for one year, a migrant cohort (n=27) that emigrated to the U.S. and a second non-migrant cohort (n=26) in the Philippines. The one-year retention rate was 96% The migrant cohort arrived in the U.S. within 2 months of their baseline assessment. Migrants and non-migrants did not differ with regard to body mass index, waist circumference or waist to hip ratio at baseline or at follow-up. It is feasible to conduct a transnational, longitudinal study of two cohorts of Filipinos. This design provides important pre-migration information, is analogous to a natural experiment, can be upscaled, and allows for a rigorous examination of immigrant health. PMID:25913346

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

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

Predictors of attrition from care at 2 years in a prospective cohort of HIV-infected adults in Tigray, Ethiopia

PubMed Central

Bucciardini, Raffaella; Fragola, Vincenzo; Abegaz, Teshome; Lucattini, Stefano; Halifom, Atakilt; Tadesse, Eskedar; Berhe, Micheal; Pugliese, Katherina; Fucili, Luca; Gregorio, Massimiliano Di; Mirra, Marco; Castro, Paola De; Terlizzi, Roberta; Tatarelli, Paola; Binelli, Andrea; Zegeye, Teame; Campagnoli, Michela; Vella, Stefano; Abraham, Loko; Godefay, Hagos

2017-01-01

Introduction Ethiopia has experienced rapid expansion of antiretroviral therapy (ART). However, as long-term retention in ART therapy is key for ART effectiveness, determinants of attrition need to be identified so appropriate interventions can be designed. Methods We used data from the ‘Cohort of African people Starting Antiretroviral therapy’ (CASA) project, a prospective study of a cohort of HIV-infected patients who started ART in seven health facilities (HFs). We analysed the data of patients who had started first-line ART between January 2013 and December 2014. The Kaplan–Meier method was used to estimate the probability of retention at different time points. The Cox proportional hazards model was used to identify factors associated with attrition. Results A total of 1198 patients were included in the study. Kaplan–Meier estimates of retention in care were 83.9%, 82.1% and 79.8% at 12, 18 and 24 months after starting ART, respectively. Attrition was mainly due to loss to follow-up, transferred-out patients and documented mortality. A multivariate Cox proportional hazard model showed that male sex, CD4 count <200 cells/µL and the type of HF were significantly associated with attrition. Conclusions The observed attrition differences according to gender suggest that separate interventions designed for women and men should be explored. Moreover, innovative strategies to increase HIV testing should be supported to avoid CD4 levels falling too low, a factor significantly associated with higher attrition in our study. Finally, specific studies to analyse the reasons for different levels of attrition among HFs are required. PMID:29082011

Cumulative exposure to air pollution and long term outcomes after first acute myocardial infarction: A population-based cohort study. Objectives and methodology

PubMed Central

2010-01-01

Background Cardiovascular disease is a leading cause of morbidity and mortality worldwide and epidemiological studies have consistently shown an increased risk for cardiovascular events in relation to exposure to air pollution. The Israel Study of First Acute Myocardial Infarction was designed to longitudinally assess clinical outcomes, psychosocial adjustment and quality of life in patients hospitalized with myocardial infarction. The current study, by introducing retrospective air pollution data, will examine the association between exposure to air pollution and outcome in myocardial infarction survivors. This report will describe the methods implemented and measures employed. The study specifically aims to examine the relationship between residential exposure to air pollution and long-term risk of recurrent coronary event, heart failure, stroke, cardiac and all-cause death in a geographically defined cohort of patients with myocardial infarction. Methods/Design All 1521 patients aged ≤65 years, admitted with first myocardial infarction between February 1992 and February 1993 to the 8 hospitals serving the population of central Israel, were followed for a median of 13 years. Data were collected on sociodemographic, clinical and environmental factors. Data from air quality monitoring stations will be incorporated retrospectively. Daily measures of air pollution will be summarised, allowing detailed maps to be developed in order to reflect chronic exposure for each participant. Discussion This study addresses some of the gaps in understanding of the prognostic importance of air pollution exposure after myocardial infarction, by allowing a sufficient follow-up period, using a well-defined community cohort, adequately controlling for multiple and multilevel confounding factors and providing extensive data on various outcomes. PMID:20576121

Transforming the Economics Curriculum by Integrating Threshold Concepts

ERIC Educational Resources Information Center

Karunaratne, Prashan Shayanka Mendis; Breyer, Yvonne A.; Wood, Leigh N.

2016-01-01

Purpose: Economics is catering to a diverse student cohort. This cohort needs to be equipped with transformative concepts that students can integrate beyond university. When a curriculum is content-driven, threshold concepts are a useful tool in guiding curriculum re-design. The paper aims to discuss these issues. Design/Methodology/Approach: The…

77 FR 9251 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-16

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Centers for..., for a number of work days aggregating at least 250 work days, occurring either solely under this...

77 FR 32640 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-01

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Centers for... Occupational Illness Compensation Program Act of 2000. On May 11, 2012, the Secretary of HHS designated the... submitted by email to [email protected] . John Howard, Director, National Institute for Occupational Safety and...

The radiologic technologists' health study in South Korea: study design and baseline results.

PubMed

Lee, Won Jin; Ha, Mina; Hwang, Seung-sik; Lee, Kyoung-Mu; Jin, Young-Woo; Jeong, Meeseon; Jun, Jae Kwan; Cha, Eun Shil; Ko, Yousun; Choi, Kyung-Hwa; Lee, Jung-Eun

2015-08-01

To describe the study design, methods, and baseline results of a prospective cohort of radiologic technologists which we have initiated in South Korea. The cohort participants were enrolled through a self-administered questionnaire survey administered from April 2012 to May 2013. Survey data were linked with radiation dosimetry, a cancer registry, and health insurance data by personal identification numbers. A nationwide representative survey was also conducted using a stratified random sampling design with face-to-face interviews. A total of 12,387 radiologic technologists were enrolled, which accounted for approximately 63% of all diagnostic radiologic technologists working in South Korea. For nationwide survey, 585 workers were interviewed using the detailed questionnaire, and buccal cells were also collected by scraping the inside of the cheek. The majority of study subjects were under 50-year-old and male workers. The average annual effective dose of radiation declined both men (from 2.75 to 1.43 mSv) and women (from 1.34 to 0.95 mSv) over the period of 1996-2011. A total of 99 cancers (66 cancers in men and 33 in women) were reported from 1992 to 2010. The standardized incidence ratio of all cancer combined was significantly lower in men (SIR = 0.75, 95% CI 0.58-0.96) than general population, but the ratios for thyroid cancer were significantly higher than expected among both men and women. This cohort provides comprehensive information on work activities and health status of diagnostic radiologic technologists. In addition, the nationwide representative sample provides unique opportunities compared with previous radiologic technologist studies.

Effects of physical activity calorie expenditure (PACE) labeling: study design and baseline sample characteristics.

PubMed

Viera, Anthony J; Tuttle, Laura; Olsson, Emily; Gras-Najjar, Julie; Gizlice, Ziya; Hales, Derek; Linnan, Laura; Lin, Feng-Chang; Noar, Seth M; Ammerman, Alice

2017-09-12

Obesity and physical inactivity are responsible for more than 365,000 deaths per year and contribute substantially to rising healthcare costs in the US, making clear the need for effective public health interventions. Calorie labeling on menus has been implemented to guide consumer ordering behaviors, but effects on calories purchased has been minimal. In this project, we tested the effect of physical activity calorie expenditure (PACE) food labels on actual point-of-decision food purchasing behavior as well as physical activity. Using a two-group interrupted time series cohort study design in three worksite cafeterias, one cafeteria was assigned to the intervention condition, and the other two served as controls. Calories from food purchased in the cafeteria were assessed by photographs of meals (accompanied by notes made on-site) using a standardized calorie database and portion size-estimation protocol. Primary outcomes will be average calories purchased and minutes of moderate to vigorous physical activity (MVPA) by individuals in the cohorts. We will compare pre-post changes in study outcomes between study groups using piecewise generalized linear mixed model regressions (segmented regressions) with a single change point in our interrupted time-series study. The results of this project will provide evidence of the effectiveness of worksite cafeteria menu labeling, which could potentially inform policy intervention approaches. Labels that convey information in a more readily understandable manner may be more effective at motivating behavior change. Strengths of this study include its cohort design and its robust data capture methods using food photographs and accelerometry.

Induction of Labor in a Contemporary Obstetric Cohort

PubMed Central

Laughon, S. Katherine; Zhang, Jun; Grewal, Jagteshwar; Sundaram, Rajeshwari; Beaver, Julie; Reddy, Uma M.

2012-01-01

Objective To describe details of labor induction, including precursors and methods, and associated vaginal delivery rates. Study Design A retrospective cohort study of 208,695 electronic medical records from 19 hospitals across the United States, 2002–2008. Results Induction occurred in 42.9% of nulliparas and 31.8% of multiparas and elective or no recorded indication for induction at term occurred in 35.5% and 44.1%, respectively. Elective induction at term in multiparas was highly successful (vaginal delivery 97%) compared to nulliparas (76.2%). For all precursors, cesarean delivery was more common in nulliparas in the latent compared to active phase of labor. Regardless of method, vaginal delivery rates were higher with a ripe versus unripe cervix, particularly for multiparas (86.6 – 100%). Conclusions Induction of labor was a common obstetric intervention. Selecting appropriate candidates and waiting longer for labor to progress into the active phase would make an impact on decreasing the national cesarean delivery rate. PMID:22520652

Loss of Magnet® Designation and Changes in RN Work Engagement: A Report on How 1 Hospital's Culture Changed Over Time.

PubMed

Wonder, Amy Hagedorn; York, Jacki; Jackson, Kathryn L; Sluys, Teresa D

2017-10-01

The aim of this study was to examine the loss of Magnet® designation and how RNs' work engagement changed at 1 community hospital. The importance of RN work engagement to promote quality and safety is widely recognized in healthcare. Ongoing consistent research is critical to determine what organizational structures are needed to support RN work engagement. This was a comparative, descriptive, correlational study of RN cohorts at 2 time points: time 1 (T1), in 2011 during Magnet designation (n = 119), and time 2 (T2), in 2016, approximately 2 years after the loss of Magnet designation (n = 140). The cohort of RNs at T2 reported significantly lower work engagement in the time period after the loss of Magnet designation when compared with the RN cohort at T1 during Magnet designation (P ≤ .0002). These results provide insights for clinical leaders striving to support a culture of RN work engagement and quality care.

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.

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

HIV Incidence and Risk Factors in Chinese Young Men Who Have Sex with Men—A Prospective Cohort Study

PubMed Central

Zhang, Hongbo; Dou, Zhi; Mi, Guodong; Ruan, Yuhua; Shen, Limei; Min, Xiangdong; Lan, Guanghua; Li, Fan; Li, Tian; Ning, Zhen; Wu, Guohui; She, Min; Wu, Zunyou

2014-01-01

Objectives To assess HIV incidence and its associated risk factors among young men who have sex with men (YMSM) in urban areas, China. Design The study used a prospective cohort study design and standard diagnostic tests. Methods A twelve-month prospective cohort study was conducted among YMSM (18–25 years old) in 8 large cities in China. The participants were recruited via snowball sampling. A total of 1102 HIV-negative YMSM completed baseline assessment, 878 YMSM participants completed 6-month follow-up, and 902 completed 12-month follow-up. HIV was screened by an enzyme-linked immunosorbent assay and confirmed with Western Blot. Syphilis was screened via rapid plasma reagent and confirmed by treponema pallidum particle agglutination assay. Results 78 HIV seroconversions were identified within 1168.4 person-year observations yielding an incidence rate of 6.7 per 100 person-years. HIV seroconversion was associated with non-student status (RR = 2.61, 90% CI = 1.3–5.26), low HIV transmission knowledge (RR = 8.87, 90% CI = 2.16–36.43), and syphilis infection (RR = 5.04, 90% CI = 2.57–9.90). Conclusions Incidence of HIV among YMSM is high in urban areas of China. Interventions measures are required to contain the HIV epidemic within this population. PMID:24878586

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.

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

Virtual Reality for Management of Pain in Hospitalized Patients: Results of a Controlled Trial

PubMed Central

Mosadeghi, Sasan; Lopez, Mayra; Dupuy, Taylor; Reid, Mark; Martinez, Bibiana; Ahmed, Shahzad; Dailey, Francis; Robbins, Karen; Rosen, Bradley; Fuller, Garth; Danovitch, Itai; IsHak, Waguih

2017-01-01

Background Improvements in software and design and reduction in cost have made virtual reality (VR) a practical tool for immersive, three-dimensional (3D), multisensory experiences that distract patients from painful stimuli. Objective The objective of the study was to measure the impact of a onetime 3D VR intervention versus a two-dimensional (2D) distraction video for pain in hospitalized patients. Methods We conducted a comparative cohort study in a large, urban teaching hospital in medical inpatients with an average pain score of ≥3/10 from any cause. Patients with nausea, vomiting, dementia, motion sickness, stroke, seizure, and epilepsy and those placed in isolation were excluded. Patients in the intervention cohort viewed a 3D VR experience designed to reduce pain using the Samsung Gear Oculus VR headset; control patients viewed a high-definition, 2D nature video on a 14-inch bedside screen. Pre- and postintervention pain scores were recorded. Difference-in-difference scores and the proportion achieving a half standard deviation pain response were compared between groups. Results There were 50 subjects per cohort (N=100). The mean pain reduction in the VR cohort was greater than in controls (−1.3 vs −0.6 points, respectively; P=.008). A total of 35 (65%) patients in the VR cohort achieved a pain response versus 40% of controls (P=.01; number needed to treat=4). No adverse events were reported from VR. Conclusions Use of VR in hospitalized patients significantly reduces pain versus a control distraction condition. These results indicate that VR is an effective and safe adjunctive therapy for pain management in the acute inpatient setting; future randomized trials should confirm benefit with different visualizations and exposure periods. Trial Registration Clinicaltrials.gov NCT02456987; https://clinicaltrials.gov/ct2/show/NCT02456987 (Archived by WebCite at http://www.webcitation.org/6pJ1P644S) PMID:28356241

Signatures of tumour immunity distinguish Asian and non-Asian gastric adenocarcinomas.

PubMed

Lin, Suling J; Gagnon-Bartsch, Johann A; Tan, Iain Beehuat; Earle, Sophie; Ruff, Louise; Pettinger, Katherine; Ylstra, Bauke; van Grieken, Nicole; Rha, Sun Young; Chung, Hyun Cheol; Lee, Ju-Seog; Cheong, Jae Ho; Noh, Sung Hoon; Aoyama, Toru; Miyagi, Yohei; Tsuburaya, Akira; Yoshikawa, Takaki; Ajani, Jaffer A; Boussioutas, Alex; Yeoh, Khay Guan; Yong, Wei Peng; So, Jimmy; Lee, Jeeyun; Kang, Won Ki; Kim, Sung; Kameda, Yoichi; Arai, Tomio; Zur Hausen, Axel; Speed, Terence P; Grabsch, Heike I; Tan, Patrick

2015-11-01

Differences in gastric cancer (GC) clinical outcomes between patients in Asian and non-Asian countries has been historically attributed to variability in clinical management. However, recent international Phase III trials suggest that even with standardised treatments, GC outcomes differ by geography. Here, we investigated gene expression differences between Asian and non-Asian GCs, and if these molecular differences might influence clinical outcome. We compared gene expression profiles of 1016 GCs from six Asian and three non-Asian GC cohorts, using a two-stage meta-analysis design and a novel biostatistical method (RUV-4) to adjust for technical variation between cohorts. We further validated our findings by computerised immunohistochemical analysis on two independent tissue microarray (TMA) cohorts from Asian and non-Asian localities (n=665). Gene signatures differentially expressed between Asians and non-Asian GCs were related to immune function and inflammation. Non-Asian GCs were significantly enriched in signatures related to T-cell biology, including CTLA-4 signalling. Similarly, in the TMA cohorts, non-Asian GCs showed significantly higher expression of T-cell markers (CD3, CD45R0, CD8) and lower expression of the immunosuppressive T-regulatory cell marker FOXP3 compared to Asian GCs (p<0.05). Inflammatory cell markers CD66b and CD68 also exhibited significant cohort differences (p<0.05). Exploratory analyses revealed a significant relationship between tumour immunity factors, geographic locality-specific prognosis, and postchemotherapy outcomes. Analyses of >1600 GCs suggest that Asian and non-Asian GCs exhibit distinct tumour immunity signatures related to T-cell function. These differences may influence geographical differences in clinical outcome, and the design of future trials particularly in immuno-oncology. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Inter-examiner classification reliability of Mechanical Diagnosis and Therapy for extremity problems - Systematic review.

PubMed

Takasaki, Hiroshi; Okuyama, Kousuke; Rosedale, Richard

2017-02-01

Mechanical Diagnosis and Therapy (MDT) is used in the treatment of extremity problems. Classifying clinical problems is one method of providing effective treatment to a target population. Classification reliability is a key factor to determine the precise clinical problem and to direct an appropriate intervention. To explore inter-examiner reliability of the MDT classification for extremity problems in three reliability designs: 1) vignette reliability using surveys with patient vignettes, 2) concurrent reliability, where multiple assessors decide a classification by observing someone's assessment, 3) successive reliability, where multiple assessors independently assess the same patient at different times. Systematic review with data synthesis in a quantitative format. Agreement of MDT subgroups was examined using the Kappa value, with the operational definition of acceptable reliability set at ≥ 0.6. The level of evidence was determined considering the methodological quality of the studies. Six studies were included and all studies met the criteria for high quality. Kappa values for the vignette reliability design (five studies) were ≥ 0.7. There was data from two cohorts in one study for the concurrent reliability design and the Kappa values ranged from 0.45 to 1.0. Kappa values for the successive reliability design (data from three cohorts in one study) were < 0.6. The current review found strong evidence of acceptable inter-examiner reliability of MDT classification for extremity problems in the vignette reliability design, limited evidence of acceptable reliability in the concurrent reliability design and unacceptable reliability in the successive reliability design. Copyright © 2017 Elsevier Ltd. All rights reserved.

77 FR 15759 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... Services (HHS). ACTION: Notice. SUMMARY: HHS gives notice concerning the final effect of the HHS decision...

78 FR 3897 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-17

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... number of work days aggregating at least 250 work days, occurring either solely under this employment or...

78 FR 3898 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-17

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... number of work days aggregating at least 250 work days, occurring either solely under this employment or...

78 FR 3898 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-17

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health..., 1955, for a number of work days aggregating at least 250 work days, occurring either solely under this...

Cultivating cohort studies for observational translational research.

PubMed

Ransohoff, David F

2013-04-01

"Discovery" research about molecular markers for diagnosis, prognosis, or prediction of response to therapy has frequently produced results that were not reproducible in subsequent studies. What are the reasons, and can observational cohorts be cultivated to provide strong and reliable answers to those questions? Experimental Selected examples are used to illustrate: (i) what features of research design provide strength and reliability in observational studies about markers of diagnosis, prognosis, and response to therapy? (ii) How can those design features be cultivated in existing observational cohorts, for example, within randomized controlled clinical trial (RCT), other existing observational research studies, or practice settings like health maintenance organization (HMOs)? Examples include a study of RNA expression profiles of tumor tissue to predict prognosis of breast cancer, a study of serum proteomics profiles to diagnose ovarian cancer, and a study of stool-based DNA assays to screen for colon cancer. Strengths and weaknesses of observational study design features are discussed, along with lessons about how features that help assure strength might be "cultivated" in the future. By considering these examples and others, it may be possible to develop a process of "cultivating cohorts" in ongoing RCTs, observational cohort studies, and practice settings like HMOs that have strong features of study design. Such an effort could produce sources of data and specimens to reliably answer questions about the use of molecular markers in diagnosis, prognosis, and response to therapy.

A prospective cohort and extended comprehensive-cohort design provided insights about the generalizability of a pragmatic trial: the ProtecT prostate cancer trial.

PubMed

Donovan, Jenny L; Young, Grace J; Walsh, Eleanor I; Metcalfe, Chris; Lane, J Athene; Martin, Richard M; Tazewell, Marta K; Davis, Michael; Peters, Tim J; Turner, Emma L; Mills, Nicola; Khazragui, Hanan; Khera, Tarnjit K; Neal, David E; Hamdy, Freddie C

2018-04-01

Randomized controlled trials (RCTs) deliver robust internally valid evidence but generalizability is often neglected. Design features built into the Prostate testing for cancer and Treatment (ProtecT) RCT of treatments for localized prostate cancer (PCa) provided insights into its generalizability. Population-based cluster randomization created a prospective study of prostate-specific antigen (PSA) testing and a comprehensive-cohort study including groups choosing treatment or excluded from the RCT, as well as those randomized. Baseline information assessed selection and response during RCT conduct. The prospective study (82,430 PSA-tested men) represented healthy men likely to respond to a screening invitation. The extended comprehensive cohort comprised 1,643 randomized, 997 choosing treatment, and 557 excluded with advanced cancer/comorbidities. Men choosing treatment were very similar to randomized men except for having more professional/managerial occupations. Excluded men were similar to the randomized socio-demographically but different clinically, representing less healthy men with more advanced PCa. The design features of the ProtecT RCT provided data to assess the representativeness of the prospective cohort and generalizability of the findings of the RCT. Greater attention to collecting data at the design stage of pragmatic trials would better support later judgments by clinicians/policy-makers about the generalizability of RCT findings in clinical practice. Copyright © 2018 The Authors. Published by Elsevier Inc. 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.

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.

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.

What's in a Name? The Incorrect Use of Case Series as a Study Design Label in Studies Involving Dogs and Cats.

PubMed

Sargeant, J M; O'Connor, A M; Cullen, J N; Makielski, K M; Jones-Bitton, A

2017-07-01

Study design labels are used to identify relevant literature to address specific clinical and research questions and to aid in evaluating the evidentiary value of research. Evidence from the human healthcare literature indicates that the label "case series" may be used inconsistently and inappropriately. Our primary objective was to determine the proportion of studies in the canine and feline veterinary literature labeled as case series that actually corresponded to descriptive cohort studies, population-based cohort studies, or other study designs. Our secondary objective was to identify the proportion of case series in which potentially inappropriate inferential statements were made. Descriptive evaluation of published literature. One-hundred published studies (from 19 journals) labeled as case series. Studies were identified by a structured literature search, with random selection of 100 studies from the relevant citations. Two reviewers independently characterized each study, with disagreements resolved by consensus. Of the 100 studies, 16 were case series. The remaining studies were descriptive cohort studies (35), population-based cohort studies (36), or other observational or experimental study designs (13). Almost half (48.8%) of the case series or descriptive cohort studies, with no control group and no formal statistical analysis, included inferential statements about the efficacy of treatment or statistical significance of potential risk factors. Authors, peer-reviewers, and editors should carefully consider the design elements of a study to accurately identify and label the study design. Doing so will facilitate an understanding of the evidentiary value of the results. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Methodology Series Module 3: Cross-sectional Studies.

PubMed

Setia, Maninder Singh

2016-01-01

Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.

Methodology Series Module 3: Cross-sectional Studies

PubMed Central

Setia, Maninder Singh

2016-01-01

Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case–control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design. PMID:27293245

A Review of the Study Designs and Statistical Methods Used in the Determination of Predictors of All-Cause Mortality in HIV-Infected Cohorts: 2002–2011

PubMed Central

Otwombe, Kennedy N.; Petzold, Max; Martinson, Neil; Chirwa, Tobias

2014-01-01

Background Research in the predictors of all-cause mortality in HIV-infected people has widely been reported in literature. Making an informed decision requires understanding the methods used. Objectives We present a review on study designs, statistical methods and their appropriateness in original articles reporting on predictors of all-cause mortality in HIV-infected people between January 2002 and December 2011. Statistical methods were compared between 2002–2006 and 2007–2011. Time-to-event analysis techniques were considered appropriate. Data Sources Pubmed/Medline. Study Eligibility Criteria Original English-language articles were abstracted. Letters to the editor, editorials, reviews, systematic reviews, meta-analysis, case reports and any other ineligible articles were excluded. Results A total of 189 studies were identified (n = 91 in 2002–2006 and n = 98 in 2007–2011) out of which 130 (69%) were prospective and 56 (30%) were retrospective. One hundred and eighty-two (96%) studies described their sample using descriptive statistics while 32 (17%) made comparisons using t-tests. Kaplan-Meier methods for time-to-event analysis were commonly used in the earlier period (n = 69, 76% vs. n = 53, 54%, p = 0.002). Predictors of mortality in the two periods were commonly determined using Cox regression analysis (n = 67, 75% vs. n = 63, 64%, p = 0.12). Only 7 (4%) used advanced survival analysis methods of Cox regression analysis with frailty in which 6 (3%) were used in the later period. Thirty-two (17%) used logistic regression while 8 (4%) used other methods. There were significantly more articles from the first period using appropriate methods compared to the second (n = 80, 88% vs. n = 69, 70%, p-value = 0.003). Conclusion Descriptive statistics and survival analysis techniques remain the most common methods of analysis in publications on predictors of all-cause mortality in HIV-infected cohorts while prospective research designs are favoured. Sophisticated techniques of time-dependent Cox regression and Cox regression with frailty are scarce. This motivates for more training in the use of advanced time-to-event methods. PMID:24498313

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

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

2015-05-04

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. 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. We used referrals, Facebook, formal advertising, and incentives in order to recruit the cohort. 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. 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.

Impact of the Good Behavior Game, a Universal Classroom–Based Behavior Intervention, on Young Adult Service Use for Problems with Emotions, Behavior, or Drugs or Alcohol

PubMed Central

Poduska, Jeanne; Kellam, Sheppard; Wang, Wei; Brown, C. Hendricks; Ialongo, Nicholas; Toyinbo, Peter

2009-01-01

Background The Good Behavior Game (GBG) is a classroom behavior management strategy focused on socializing children to the role of student and aimed at reducing early aggressive, disruptive behavior, a confirmed antecedent to service use. The GBG was tested in a randomized field trial in 19 elementary schools in two cohorts of children as they attended first and second grades. This article reports on the impact of the GBG on service use through young adulthood. Methods Three or four schools in each of five urban areas were matched and randomly assigned to one of three conditions: 1) GBG, 2) an intervention aimed at academic achievement, or 3) the standard program of the school system. Children were assigned to classrooms to ensure balance, and teachers and classrooms were randomly assigned to intervention conditions. Results This study provides evidence of a positive impact of a universal preventive intervention on later service use by males, although not by females, for problems with emotions, behavior, or drugs or alcohol. For both cohorts, males in GBG classrooms who had been rated as highly aggressive, disruptive by their teachers in the fall of first grade had a lower rate of school-based service use than their counterparts in control classrooms. Replication The design employed two cohorts of students. Although both first- and second-grade teachers received less training and support with the second cohorts of students than with the first cohort, the impact of GBG was similar across both cohorts. PMID:18249508

Longitudinal Study of New and Prevalent Use of Self-Monitoring of Blood Glucose

PubMed Central

Karter, Andrew J.; Parker, Melissa M.; Moffet, Howard H.; Spence, Michele M.; Chan, James; Ettner, Susan L.; Selby, Joe V.

2008-01-01

OBJECTIVE We sought to assess longitudinal association between self-monitoring of blood glucose (SMBG) and glycemic control in diabetic patients from an integrated health plan (Kaiser Permanente Northern California). RESEARCH DESIGN AND METHODS Longitudinal analyses of glycemic control among 1) 16,091 patients initiating SMBG (new-user cohort) and 2) 15,347 ongoing users of SMBG (prevalent-user cohort). SMBG frequency was based on pharmacy use (number of blood glucose test strips dispensed), and glycemic control was based on HbA1c (A1C). In the new-user cohort, ANCOVA models (pre- and posttest design) were used to assess the effect of initiating SMBG. In the prevalent-user cohort, repeated-measure, mixed-effects models with random-intercept and time-dependent covariates were used to assess changes in SMBG and A1C. All models were stratified by therapy (no medications, oral agents only, or insulin) and adjusted for baseline A1C, sociodemographics, insulin injection frequency, comorbidity index, medication adherence, smoking status, health care use, and provider specialty. RESULTS Greater SMBG practice frequency among new users was associated with a graded decrease in A1C (relative to nonusers) regardless of diabetes therapy (P < 0.0001). Changes in SMBG frequency among prevalent users were associated with an inverse graded change in A1C only among pharmacologically treated patients (P < 0.0001). CONCLUSIONS These observational findings are consistent with short-term benefits of initiating SMBG practice for all patients but continuing benefits only for pharmacologically treated patients. Differences in effectiveness between new versus prevalent users of SMBG have implications for guideline development and interpretation of observational outcomes data. PMID:16873776

Current management and prognostic factors in physiotherapy practice for patients with shoulder pain: design of a prospective cohort study.

PubMed

Karel, Yasmaine H J M; Scholten-Peeters, Wendy G M; Thoomes-de Graaf, Marloes; Duijn, Edwin; Ottenheijm, Ramon P G; van den Borne, Maaike P J; Koes, Bart W; Verhagen, Arianne P; Dinant, Geert-Jan; Tetteroo, Eric; Beumer, Annechien; van Broekhoven, Joost B; Heijmans, Marcel

2013-02-11

Shoulder pain is disabling and has a considerable socio-economic impact. Over 50% of patients presenting in primary care still have symptoms after 6 months; moreover, prognostic factors such as pain intensity, age, disability level and duration of complaints are associated with poor outcome. Most shoulder complaints in this group are categorized as non-specific. Musculoskeletal ultrasound might be a useful imaging method to detect subgroups of patients with subacromial disorders.This article describes the design of a prospective cohort study evaluating the influence of known prognostic and possible prognostic factors, such as findings from musculoskeletal ultrasound outcome and working alliance, on the recovery of shoulder pain. Also, to assess the usual physiotherapy care for shoulder pain and examine the inter-rater reliability of musculoskeletal ultrasound between radiologists and physiotherapists for patients with shoulder pain. A prospective cohort study including an inter-rater reliability study. Patients presenting in primary care physiotherapy practice with shoulder pain are enrolled. At baseline validated questionnaires are used to measure patient characteristics, disease-specific characteristics and social factors. Physical examination is performed according to the expertise of the physiotherapists. Follow-up measurements will be performed 6, 12 and 26 weeks after inclusion. Primary outcome measure is perceived recovery, measured on a 7-point Likert scale. Logistic regression analysis will be used to evaluate the association between prognostic factors and recovery. The ShoCoDiP (Shoulder Complaints and using Diagnostic ultrasound in Physiotherapy practice) cohort study will provide information on current management of patients with shoulder pain in primary care, provide data to develop a prediction model for shoulder pain in primary care and to evaluate whether musculoskeletal ultrasound can improve prognosis.

Regression of Moral Reasoning during Medical Education: Combined Design Study to Evaluate the Effect of Clinical Study Years

PubMed Central

Hren, Darko; Marušić, Matko; Marušić, Ana

2011-01-01

Background Moral reasoning is important for developing medical professionalism but current evidence for the relationship between education and moral reasoning does not clearly apply to medical students. We used a combined study design to test the effect of clinical teaching on moral reasoning. Methods We used the Defining Issues Test-2 as a measure of moral judgment, with 3 general moral schemas: Personal Interest, Maintaining Norms, and Postconventional Schema. The test was applied to 3 consecutive cohorts of second year students in 2002 (n = 207), 2003 (n = 192), and 2004 (n = 139), and to 707 students of all 6 study years in 2004 cross-sectional study. We also tested 298 age-matched controls without university education. Results In the cross-sectional study, there was significant main effect of the study year for Postconventional (F(5,679) = 3.67, P = 0.003) and Personal Interest scores (F(5,679) = 3.38, P = 0.005). There was no effect of the study year for Maintaining Norms scores. 3rd year medical students scored higher on Postconventional schema score than all other study years (p<0.001). There were no statistically significant differences among 3 cohorts of 2nd year medical students, demonstrating the absence of cohort or point-of-measurement effects. Longitudinal study of 3 cohorts demonstrated that students regressed from Postconventional to Maintaining Norms schema-based reasoning after entering the clinical part of the curriculum. Interpretation Our study demonstrated direct causative relationship between the regression in moral reasoning development and clinical teaching during medical curriculum. The reasons may include hierarchical organization of clinical practice, specific nature of moral dilemmas faced by medical students, and hidden medical curriculum. PMID:21479204

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

Rationale and design of a multicenter echocardiographic study to assess the relationship between cardiac structure and function and heart failure risk in a biracial cohort of community-dwelling elderly persons: the Atherosclerosis Risk in Communities study.

PubMed

Shah, Amil M; Cheng, Susan; Skali, Hicham; Wu, Justina; Mangion, Judy R; Kitzman, Dalane; Matsushita, Kunihiro; Konety, Suma; Butler, Kenneth R; Fox, Ervin R; Cook, Nakela; Ni, Hanyu; Coresh, Josef; Mosley, Thomas H; Heiss, Gerardo; Folsom, Aaron R; Solomon, Scott D

2014-01-01

Heart failure is an important public health concern, particularly among persons>65 years of age. Women and blacks are critically understudied populations that carry a sizeable portion of the heart failure burden. Limited normative and prognostic data exist on measures of cardiac structure, diastolic function, and novel measures of systolic deformation in older adults living in the community. The Atherosclerosis Risk in Communities (ARIC) study is a large, predominantly biracial, National Heart, Lung, and Blood Institute-sponsored epidemiological cohort study. Between 2011 and 2013, ≈6000 surviving participants, now in their seventh to ninth decade of life, are expected to return for a fifth study visit during which comprehensive 2-dimensional, Doppler, tissue Doppler, and speckle-tracking echocardiography will be performed uniformly in all cohort clinic visit participants. The following objectives will be addressed: (1) to characterize cardiac structural and functional abnormalities among the elderly and to determine how they differ by sex and race/ethnicity, (2) to determine the relationship between ventricular and vascular abnormalities, and (3) to prospectively examine the extent to which these noninvasive measures associate with incident heart failure. We describe the design, imaging acquisition and analysis methods, and quality assurance metrics for echocardiography in visit 5 of the ARIC cohort. A better understanding of the differences in cardiac structure and function through the spectrum of heart failure stages in elderly persons generally, and between sexes and racial/ethnic groups specifically, will deepen our understanding of the pathophysiology driving heart failure progression in these at-risk populations and may inform novel prevention or therapeutic strategies.

Fretting and Corrosion at the Backside of Modular Cobalt Chromium Acetabular Inserts: A Retrieval Analysis.

PubMed

Tarity, T David; Koch, Chelsea N; Burket, Jayme C; Wright, Timothy M; Westrich, Geoffrey H

2017-03-01

Adverse local tissue reaction formation has been suggested to occur with the Modular Dual Mobility (MDM) acetabular design. Few reports in the literature have evaluated fretting and corrosion damage between the acetabular shell and modular metal inserts in this modular system. We evaluated a series of 18 retrieved cobalt chromium MDM inserts for evidence of fretting and corrosion. We assessed the backsides of 18 MDM components for evidence of fretting and corrosion in polar and taper regions based on previously established methods. We collected and assessed 30 similarly designed modular inserts retrieved from metal-on-metal (MoM) total hip arthroplasties as a control. No specific pattern of fretting or corrosion was identified on the MDM inserts. Both fretting and corrosion were significantly greater in the MoM cohort than the MDM cohort, driven by higher fretting and corrosion scores in the engaged taper region of the MoM inserts. MoM components demonstrated more fretting and corrosion than MDM designs, specifically at the taper region, likely driven by differences in the taper engagement mechanism and geometry among the insert designs. The lack of significant fretting and corrosion observed in the MDM inserts are inconsistent with recent claims that this interface may produce clinically significant metallosis and adverse local tissue reactions. Copyright © 2016 Elsevier Inc. All rights reserved.

Study designs may influence results: the problems with questionnaire-based case-control studies on the epidemiology of glioma.

PubMed

Johansen, Christoffer; Schüz, Joachim; Andreasen, Anne-Marie Serena; Dalton, Susanne Oksbjerg

2017-03-28

Glioma is a rare brain tumour with a very poor prognosis and the search for modifiable factors is intense. We reviewed the literature concerning risk factors for glioma obtained in case-control designed epidemiological studies in order to discuss the influence of this methodology on the observed results. When reviewing the association between three exposures, medical radiation, exogenous hormone use and allergy, we critically appraised the evidence from both case-control and cohort studies. For medical radiation and hormone replacement therapy (HRT), questionnaire-based case-control studies appeared to show an inverse association, whereas nested case-control and cohort studies showed no association. For allergies, the inverse association was observed irrespective of study design. We recommend that the questionnaire-based case-control design be placed lower in the hierarchy of studies for establishing cause-and-effect for diseases such as glioma. We suggest that a state-of-the-art case-control study should, as a minimum, be accompanied by extensive validation of the exposure assessment methods and the representativeness of the study sample with regard to the exposures of interest. Otherwise, such studies cannot be regarded as 'hypothesis testing' but only 'hypothesis generating'. We consider that this holds true for all questionnaire-based case-control studies on cancer and other chronic diseases, although perhaps not to the same extent for each exposure-outcome combination.

Understanding resilience in same-sex parented families: the work, love, play study.

PubMed

Power, Jennifer J; Perlesz, Amaryll; Schofield, Margot J; Pitts, Marian K; Brown, Rhonda; McNair, Ruth; Barrett, Anna; Bickerdike, Andrew

2010-03-09

While families headed by same-sex couples have achieved greater public visibility in recent years, there are still many challenges for these families in dealing with legal and community contexts that are not supportive of same-sex relationships. The Work, Love, Play study is a large longitudinal study of same-sex parents. It aims to investigate many facets of family life among this sample and examine how they change over time. The study focuses specifically on two key areas missing from the current literature: factors supporting resilience in same-sex parented families; and health and wellbeing outcomes for same-sex couples who undergo separation, including the negotiation of shared parenting arrangements post-separation. The current paper aims to provide a comprehensive overview of the design and methods of this longitudinal study and discuss its significance. The Work, Love, Play study is a mixed design, three wave, longitudinal cohort study of same-sex attracted parents. The sample includes lesbian, gay, bisexual and transgender parents in Australia and New Zealand (including single parents within these categories) caring for any children under the age of 18 years. The study will be conducted over six years from 2008 to 2014. Quantitative data are to be collected via three on-line surveys in 2008, 2010 and 2012 from the cohort of parents recruited in Wave1. Qualitative data will be collected via interviews with purposively selected subsamples in 2012 and 2013. Data collection began in 2008 and 355 respondents to Wave One of the study have agreed to participate in future surveys. Work is currently underway to increase this sample size. The methods and survey instruments are described. This study will make an important contribution to the existing research on same-sex parented families. Strengths of the study design include the longitudinal method, which will allow understanding of changes over time within internal family relationships and social supports. Further, the mixed method design enables triangulation of qualitative and quantitative data. A broad recruitment strategy has already enabled a large sample size with the inclusion of both gay men and lesbians.

77 FR 42500 - Designation of a Class of Employees for Addition to the Special Exposure Cohort; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-19

... Special Exposure Cohort; Correction AGENCY: National Institute for Occupational Safety and Health (NIOSH... Production Center (FMPC) in Fernald, Ohio, also known as the Fernald Environmental Management Project (FEMP), as an addition to the Special Exposure Cohort (SEC) under the Energy Employees Occupational Illness...

Cohort Default Rate Guide. Revised August 2006

ERIC Educational Resources Information Center

US Department of Education, 2006

2006-01-01

This guide is designed to assist schools with their Federal Family Education Loan (FFEL) Program and William D. Ford Federal Direct Loan (Direct Loan) Program cohort default rate data. The guide is intended as a reference tool in understanding cohort default rates and processes. Material is organized into four parts: (1) Introduction; (2) General…

Value of the small cohort study including a physical examination for minor structural defects in identifying new human teratogens.

PubMed

Chambers, Christina D

2011-03-01

Most known human teratogens are associated with a unique or characteristic pattern of major and minor malformations and this pattern helps to establish the causal link between the teratogenic exposure and the outcome. Although traditional case-control and cohort study designs can help identify potential teratogens, there is an important role for small cohort studies that include a dysmorphological examination of exposed and unexposed infants for minor structural defects. In combination with other study design approaches, the small cohort study with a specialized physical examination fulfills a necessary function in screening for new potential teratogens and can help to better delineate the spectrum and magnitude of risk for known teratogens. © 2011 The Author. Congenital Anomalies © 2011 Japanese Teratology Society.

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

The incident user design in comparative effectiveness research.

PubMed

Johnson, Eric S; Bartman, Barbara A; Briesacher, Becky A; Fleming, Neil S; Gerhard, Tobias; Kornegay, Cynthia J; Nourjah, Parivash; Sauer, Brian; Schumock, Glen T; Sedrakyan, Art; Stürmer, Til; West, Suzanne L; Schneeweiss, Sebastian

2013-01-01

Comparative effectiveness research includes cohort studies and registries of interventions. When investigators design such studies, how important is it to follow patients from the day they initiated treatment with the study interventions? Our article considers this question and related issues to start a dialogue on the value of the incident user design in comparative effectiveness research. By incident user design, we mean a study that sets the cohort's inception date according to patients' new use of an intervention. In contrast, most epidemiologic studies enroll patients who were currently or recently using an intervention when follow-up began. We take the incident user design as a reasonable default strategy because it reduces biases that can impact non-randomized studies, especially when investigators use healthcare databases. We review case studies where investigators have explored the consequences of designing a cohort study by restricting to incident users, but most of the discussion has been informed by expert opinion, not by systematic evidence. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

efficient association study design via power-optimized tag SNP selection

PubMed Central

HAN, BUHM; KANG, HYUN MIN; SEO, MYEONG SEONG; ZAITLEN, NOAH; ESKIN, ELEAZAR

2008-01-01

Discovering statistical correlation between causal genetic variation and clinical traits through association studies is an important method for identifying the genetic basis of human diseases. Since fully resequencing a cohort is prohibitively costly, genetic association studies take advantage of local correlation structure (or linkage disequilibrium) between single nucleotide polymorphisms (SNPs) by selecting a subset of SNPs to be genotyped (tag SNPs). While many current association studies are performed using commercially available high-throughput genotyping products that define a set of tag SNPs, choosing tag SNPs remains an important problem for both custom follow-up studies as well as designing the high-throughput genotyping products themselves. The most widely used tag SNP selection method optimizes over the correlation between SNPs (r2). However, tag SNPs chosen based on an r2 criterion do not necessarily maximize the statistical power of an association study. We propose a study design framework that chooses SNPs to maximize power and efficiently measures the power through empirical simulation. Empirical results based on the HapMap data show that our method gains considerable power over a widely used r2-based method, or equivalently reduces the number of tag SNPs required to attain the desired power of a study. Our power-optimized 100k whole genome tag set provides equivalent power to the Affymetrix 500k chip for the CEU population. For the design of custom follow-up studies, our method provides up to twice the power increase using the same number of tag SNPs as r2-based methods. Our method is publicly available via web server at http://design.cs.ucla.edu. PMID:18702637

Correction of confounding bias in non-randomized studies by appropriate weighting.

PubMed

Schmoor, Claudia; Gall, Christine; Stampf, Susanne; Graf, Erika

2011-03-01

In non-randomized studies, the assessment of a causal effect of treatment or exposure on outcome is hampered by possible confounding. Applying multiple regression models including the effects of treatment and covariates on outcome is the well-known classical approach to adjust for confounding. In recent years other approaches have been promoted. One of them is based on the propensity score and considers the effect of possible confounders on treatment as a relevant criterion for adjustment. Another proposal is based on using an instrumental variable. Here inference relies on a factor, the instrument, which affects treatment but is thought to be otherwise unrelated to outcome, so that it mimics randomization. Each of these approaches can basically be interpreted as a simple reweighting scheme, designed to address confounding. The procedures will be compared with respect to their fundamental properties, namely, which bias they aim to eliminate, which effect they aim to estimate, and which parameter is modelled. We will expand our overview of methods for analysis of non-randomized studies to methods for analysis of randomized controlled trials and show that analyses of both study types may target different effects and different parameters. The considerations will be illustrated using a breast cancer study with a so-called Comprehensive Cohort Study design, including a randomized controlled trial and a non-randomized study in the same patient population as sub-cohorts. This design offers ideal opportunities to discuss and illustrate the properties of the different approaches. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Assay for the Identification of NOTCH1 PEST Domain Mutations in Chronic Lymphocytic Leukemia

PubMed Central

Petroni, Roberta Cardoso; Muto, Nair Hideko; Sitnik, Roberta; de Carvalho, Flavia Pereira; Bacal, Nydia Strachman; Velloso, Elvira Deolinda Rodrigues Pereira; Oliveira, Gislaine Borba; Pinho, João Renato Rebello; Torres, Davi Coe; Mansur, Marcela Braga; Hassan, Rocio; Lorand-Metze, Irene Gyongyvér Heidemarie; Chiattone, Carlos Sérgio; Hamerschlak, Nelson; Mangueira, Cristovão Luis Pitangueira

2016-01-01

Aims. To develop a fast and robust DNA-based assay to detect insertions and deletions mutations in exon 34 that encodes the PEST domain of NOTCH1 in order to evaluate patients with chronic lymphocytic leukemia (CLL). Methods. We designed a multiplexed allele-specific polymerase chain reaction (PCR) combined with a fragment analysis assay to detect specifically the mutation c.7544_7545delCT and possibly other insertions and deletions in exon 34 of NOTCH1. Results. We evaluated our assay in peripheral blood samples from two cohorts of patients with CLL. The frequency of NOTCH1 mutations was 8.4% in the first cohort of 71 unselected CLL patients. We then evaluated a second cohort of 26 CLL patients with known cytogenetic abnormalities that were enriched for patients with trisomy 12. NOTCH1 mutations were detected in 43.7% of the patients with trisomy 12. Conclusions. We have developed a fast and robust assay combining allele-specific PCR and fragment analysis able to detect NOTCH1 PEST domain insertions and deletions. PMID:28074183

Validation of the Diabetes Prevention Trial–Type 1 Risk Score in the TrialNet Natural History Study

PubMed Central

Sosenko, Jay M.; Skyler, Jay S.; Mahon, Jeffrey; Krischer, Jeffrey P.; Beam, Craig A.; Boulware, David C.; Greenbaum, Carla J.; Rafkin, Lisa E.; Cowie, Catherine; Cuthbertson, David; Palmer, Jerry P.

2011-01-01

OBJECTIVE We assessed the accuracy of the Diabetes Prevention Trial–Type 1 Risk Score (DPTRS), developed from the Diabetes Prevention Trial–Type 1 (DPT-1), in the TrialNet Natural History Study (TNNHS). RESEARCH DESIGN AND METHODS Prediction accuracy of the DPTRS was assessed with receiver-operating characteristic curve areas. The type 1 diabetes cumulative incidence within the DPTRS intervals was compared between the TNNHS and DPT-1 cohorts. RESULTS Receiver-operating characteristic curve areas for the DPTRS were substantial in the TNNHS (P < 0.001 at both 2 and 3 years). The type 1 diabetes cumulative incidence did not differ significantly between the TNNHS and DPT-1 cohorts within DPTRS intervals. In the TNNHS, 2-year and 3-year risks were low for DPTRS intervals <6.50 (<0.10 and <0.20, respectively). Thresholds ≥7.50 were indicative of high risk in both cohorts (2-year risks: 0.49 in the TNNHS and 0.51 in DPT-1). CONCLUSIONS The DPTRS is an accurate and robust predictor of type 1 diabetes in autoantibody-positive populations. PMID:21680724

Direct medical costs and medication compliance among fibromyalgia patients: duloxetine initiators vs. pregabalin initiators.

PubMed

Sun, Peter; Peng, Xiaomei; Sun, Steve; Novick, Diego; Faries, Douglas E; Andrews, Jeffrey S; Wohlreich, Madelaine M; Wu, Andrew

2014-01-01

To assess and compare direct medical costs and medication compliance between patients with fibromyalgia who initiated duloxetine and patients with fibromyalgia who initiated pregabalin in 2008. A retrospective cohort study design was used based on a large US national commercial claims database (2006 to 2009). Patients with fibromyalgia aged 18 to 64 who initiated duloxetine or pregabalin in 2008 and who had continuous health insurance 1 year preceding and 1 year following the initiation were selected into duloxetine cohort or pregabalin cohort based on their initiated agent. Medication compliance was measured by total supply days, medication possession ratio (MPR), and proportion of patients with MPR ≥ 0.8. Direct medical costs were measured by annual costs per patient and compared between the cohorts in the year following the initiation. Propensity score stratification and bootstrapping methods were used to adjust for distribution bias, as well as cross-cohort differences in demographic, clinical and economic characteristics, and medication history prior to the initiation. Both the duloxetine (n = 3,033) and pregabalin (n = 4,838) cohorts had a mean initiation age around 49 years, 89% were women. During the postindex year, compared to the pregabalin cohort, the duloxetine cohort had higher totally annual supply days (273.5 vs. 176.6, P < 0.05), higher MPR (0.7 vs. 0.5, P < 0.05), and more patients with MPR ≥ 0.8 (45.1% vs. 29.4%, P < 0.05). Further, relative to pregabalin cohort, duloxetine cohort had lower inpatient costs ($2,994.9 vs. $4,949.6, P < 0.05), lower outpatient costs ($8,259.6 vs. $10,312.2, P < 0.05), similar medication costs ($5,214.6 vs. $5,290.8, P > 0.05), and lower total medical costs ($16,469.1 vs. $20,552.6, P < 0.05) in the postinitiation year. In a real-world setting, patients with fibromyalgia who initiated duloxetine in 2008 had better medication compliance and consumed less inpatient, outpatient, and total medical costs than those who initiated pregabalin. © 2013 The Authors Pain Practice © 2013 World Institute of Pain.

Multidisciplinary design and analytic approaches to advance prospective research on the multilevel determinants of child health.

PubMed

Johnson, Sara B; Little, Todd D; Masyn, Katherine; Mehta, Paras D; Ghazarian, Sharon R

2017-06-01

Characterizing the determinants of child health and development over time, and identifying the mechanisms by which these determinants operate, is a research priority. The growth of precision medicine has increased awareness and refinement of conceptual frameworks, data management systems, and analytic methods for multilevel data. This article reviews key methodological challenges in cohort studies designed to investigate multilevel influences on child health and strategies to address them. We review and summarize methodological challenges that could undermine prospective studies of the multilevel determinants of child health and ways to address them, borrowing approaches from the social and behavioral sciences. Nested data, variation in intervals of data collection and assessment, missing data, construct measurement across development and reporters, and unobserved population heterogeneity pose challenges in prospective multilevel cohort studies with children. We discuss innovations in missing data, innovations in person-oriented analyses, and innovations in multilevel modeling to address these challenges. Study design and analytic approaches that facilitate the integration across multiple levels, and that account for changes in people and the multiple, dynamic, nested systems in which they participate over time, are crucial to fully realize the promise of precision medicine for children and adolescents. Copyright © 2017 Elsevier Inc. All rights reserved.

[Methodologies of publications in the Revista de Investigación Clínica during the last 20 years].

PubMed

López-Jiménez, F; Borovoy, J

1997-01-01

To characterize the clinical research methods published in the Revista de Investigación Clínica for the past 20 years. Comparative study of methods used in the RIC articles published in 3-years periods representing three decades (1972-74, 1982-84, 1992-94). Out of 273 original papers, 218 (80%) were of clinical research. There was an increased percentage of longitudinal vs cross-sectional studies, with cohort and randomized clinical trials showing the largest increase. The total number of research manuscripts also increased. The clinical research methods of the papers in the RIC have shown an increased rate of designs with a higher scientific value.

Worklife Improvement and Leadership Development study: a learning experience in leadership development and "planned" organizational change.

PubMed

Cummings, Greta G; Spiers, Judith A; Sharlow, Janice; Germann, Paula; Yurtseven, Ozden; Bhatti, Aslam

2013-01-01

In response to increasing recognition of the importance of quality health care work environments, the Alberta Cancer Board initiated a province-wide leadership development program to plan for organizational change through a series of stages. In 2004, the Leadership Development Initiative (LDI) was implemented to facilitate organizational learning using a cohort-based leadership intervention based on a communities of practice framework. The aim of the Worklife Improvement and Leadership Development study was to examine both the outcomes and experiences of participants of the LDI program to better understand leadership development, implementation, and its impact on worklife quality among 5 cohorts of health care managers and staff at the Alberta Cancer Board. This study used both structured survey and interview methods, using a pretest-intervention-posttest quasi-experiment without a control group design, to assess the effects of LDI on worklife of leaders and staff. Surveys included the Leadership Practices Inventory and Areas of Worklife Scale, which looked at meaningfulness of work and organizational engagement. Interviews and focus group data provided a more detailed description of the experience of leadership development and perceptions of organizational worklife. The study revealed layers of information about the complexity of individual and collective leadership in a cohort-based design, perceptions of leadership initiatives, organizational worklife, and planned organizational change. Our findings suggest that early changes in how leaders reflected on their own skills and practices (Leading Self) were positive; however, growing disengagement as the LDI continued was evident in the focus group data, particularly when change in behavior of others was not perceived to be evident. To support the effectiveness and success of a leadership initiative, managers and administrators need to implement strategies designed to help leaders grow and cope with ongoing flux of organizational change and stagnation.

Clinical Diagnoses before Age 75 and Men's Survival to Their 85th Birthday: The Manitoba Follow-Up Study

ERIC Educational Resources Information Center

Tate, Robert B.; Michaels, Leon; Cuddy, T. Edward; Bayomi, Dennis J.

2013-01-01

Purpose: Of all Canadian and American men who live to age 75 years, about half can expect to live to age 85. Our objective is to examine how clinical diagnoses made before age 75 relate to a man's survival to age 85 years. Design and Methods: Since 1948, a cohort of 3,983 young men (mean age of 31 years at entry) has been followed with routine…

Whole-Exome Sequencing in Familial Parkinson Disease

PubMed Central

Farlow, Janice L.; Robak, Laurie A.; Hetrick, Kurt; Bowling, Kevin; Boerwinkle, Eric; Coban-Akdemir, Zeynep H.; Gambin, Tomasz; Gibbs, Richard A.; Gu, Shen; Jain, Preti; Jankovic, Joseph; Jhangiani, Shalini; Kaw, Kaveeta; Lai, Dongbing; Lin, Hai; Ling, Hua; Liu, Yunlong; Lupski, James R.; Muzny, Donna; Porter, Paula; Pugh, Elizabeth; White, Janson; Doheny, Kimberly; Myers, Richard M.; Shulman, Joshua M.; Foroud, Tatiana

2016-01-01

IMPORTANCE Parkinson disease (PD) is a progressive neurodegenerative disease for which susceptibility is linked to genetic and environmental risk factors. OBJECTIVE To identify genetic variants contributing to disease risk in familial PD. DESIGN, SETTING, AND PARTICIPANTS A 2-stage study design that included a discovery cohort of families with PD and a replication cohort of familial probands was used. In the discovery cohort, rare exonic variants that segregated in multiple affected individuals in a family and were predicted to be conserved or damaging were retained. Genes with retained variants were prioritized if expressed in the brain and located within PD-relevant pathways. Genes in which prioritized variants were observed in at least 4 families were selected as candidate genes for replication in the replication cohort. The setting was among individuals with familial PD enrolled from academic movement disorder specialty clinics across the United States. All participants had a family history of PD. MAIN OUTCOMES AND MEASURES Identification of genes containing rare, likely deleterious, genetic variants in individuals with familial PD using a 2-stage exome sequencing study design. RESULTS The 93 individuals from 32 families in the discovery cohort (49.5% [46 of 93] female) had a mean (SD) age at onset of 61.8 (10.0) years. The 49 individuals with familial PD in the replication cohort (32.6% [16 of 49] female) had a mean (SD) age at onset of 50.1 (15.7) years. Discovery cohort recruitment dates were 1999 to 2009, and replication cohort recruitment dates were 2003 to 2014. Data analysis dates were 2011 to 2015. Three genes containing a total of 13 rare and potentially damaging variants were prioritized in the discovery cohort. Two of these genes (TNK2 and TNR) also had rare variants that were predicted to be damaging in the replication cohort. All 9 variants identified in the 2 replicated genes in 12 families across the discovery and replication cohorts were confirmed via Sanger sequencing. CONCLUSIONS AND RELEVANCE TNK2 and TNR harbored rare, likely deleterious, variants in individuals having familial PD, with similar findings in an independent cohort. To our knowledge, these genes have not been previously associated with PD, although they have been linked to critical neuronal functions. Further studies are required to confirm a potential role for these genes in the pathogenesis of PD. PMID:26595808

Circulating 25-hydroxyvitamin D and the risk of rarer cancers: Design and methods of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers.

PubMed

Gallicchio, Lisa; Helzlsouer, Kathy J; Chow, Wong-Ho; Freedman, D Michal; Hankinson, Susan E; Hartge, Patricia; Hartmuller, Virginia; Harvey, Chinonye; Hayes, Richard B; Horst, Ronald L; Koenig, Karen L; Kolonel, Laurence N; Laden, Francine; McCullough, Marjorie L; Parisi, Dominick; Purdue, Mark P; Shu, Xiao-Ou; Snyder, Kirk; Stolzenberg-Solomon, Rachael Z; Tworoger, Shelley S; Varanasi, Arti; Virtamo, Jarmo; Wilkens, Lynne R; Xiang, Yong-Bing; Yu, Kai; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Abnet, Christian C; Albanes, Demetrius; Bertrand, Kimberly; Weinstein, Stephanie J

2010-07-01

The Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP), a consortium of 10 prospective cohort studies from the United States, Finland, and China, was formed to examine the associations between circulating 25-hydroxyvitamin D (25(OH)D) concentrations and the risk of rarer cancers. Cases (total n = 5,491) included incident primary endometrial (n = 830), kidney (n = 775), ovarian (n = 516), pancreatic (n = 952), and upper gastrointestinal tract (n = 1,065) cancers and non-Hodgkin lymphoma (n = 1,353) diagnosed in the participating cohorts. At least 1 control was matched to each case on age, date of blood collection (1974-2006), sex, and race/ethnicity (n = 6,714). Covariate data were obtained from each cohort in a standardized manner. The majority of the serum or plasma samples were assayed in a central laboratory using a direct, competitive chemiluminescence immunoassay on the DiaSorin LIAISON platform (DiaSorin, Inc., Stillwater, Minnesota). Masked quality control samples included serum standards from the US National Institute of Standards and Technology. Conditional logistic regression analyses were conducted using clinically defined cutpoints, with 50-<75 nmol/L as the reference category. Meta-analyses were also conducted using inverse-variance weights in random-effects models. This consortium approach permits estimation of the association between 25(OH)D and several rarer cancers with high accuracy and precision across a wide range of 25(OH)D concentrations.

Circulating 25-Hydroxyvitamin D and the Risk of Rarer Cancers: Design and Methods of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers

PubMed Central

Gallicchio, Lisa; Helzlsouer, Kathy J.; Chow, Wong-Ho; Freedman, D. Michal; Hankinson, Susan E.; Hartge, Patricia; Hartmuller, Virginia; Harvey, Chinonye; Hayes, Richard B.; Horst, Ronald L.; Koenig, Karen L.; Kolonel, Laurence N.; Laden, Francine; McCullough, Marjorie L.; Parisi, Dominick; Purdue, Mark P.; Shu, Xiao-Ou; Snyder, Kirk; Stolzenberg-Solomon, Rachael Z.; Tworoger, Shelley S.; Varanasi, Arti; Virtamo, Jarmo; Wilkens, Lynne R.; Xiang, Yong-Bing; Yu, Kai; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Abnet, Christian C.; Albanes, Demetrius; Bertrand, Kimberly; Weinstein, Stephanie J.

2010-01-01

The Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP), a consortium of 10 prospective cohort studies from the United States, Finland, and China, was formed to examine the associations between circulating 25-hydroxyvitamin D (25(OH)D) concentrations and the risk of rarer cancers. Cases (total n = 5,491) included incident primary endometrial (n = 830), kidney (n = 775), ovarian (n = 516), pancreatic (n = 952), and upper gastrointestinal tract (n = 1,065) cancers and non-Hodgkin lymphoma (n = 1,353) diagnosed in the participating cohorts. At least 1 control was matched to each case on age, date of blood collection (1974–2006), sex, and race/ethnicity (n = 6,714). Covariate data were obtained from each cohort in a standardized manner. The majority of the serum or plasma samples were assayed in a central laboratory using a direct, competitive chemiluminescence immunoassay on the DiaSorin LIAISON platform (DiaSorin, Inc., Stillwater, Minnesota). Masked quality control samples included serum standards from the US National Institute of Standards and Technology. Conditional logistic regression analyses were conducted using clinically defined cutpoints, with 50–<75 nmol/L as the reference category. Meta-analyses were also conducted using inverse-variance weights in random-effects models. This consortium approach permits estimation of the association between 25(OH)D and several rarer cancers with high accuracy and precision across a wide range of 25(OH)D concentrations. PMID:20562188

Mapping Anterior Temporal Lobe Language Areas with FMRI: A Multi-Center Normative Study

PubMed Central

Binder, Jeffrey R.; Gross, William L.; Allendorfer, Jane B.; Bonilha, Leonardo; Chapin, Jessica; Edwards, Jonathan C.; Grabowski, Thomas J.; Langfitt, John T.; Loring, David W.; Lowe, Mark J.; Koenig, Katherine; Morgan, Paul S.; Ojemann, Jeffrey G.; Rorden, Christopher; Szaflarski, Jerzy P.; Tivarus, Madalina E.; Weaver, Kurt E.

2010-01-01

Removal of the anterior temporal lobe (ATL) is an effective surgical treatment for intractable temporal lobe epilepsy but carries a risk of language and verbal memory deficits. Preoperative localization of functional zones in the ATL might help reduce these risks, yet fMRI protocols in current widespread use produce very little activation in this region. Based on recent evidence suggesting a role for the ATL in semantic integration, we designed an fMRI protocol comparing comprehension of brief narratives (Story task) with a semantically shallow control task involving serial arithmetic (Math task). The Story > Math contrast elicited strong activation throughout the ATL, lateral temporal lobe, and medial temporal lobe bilaterally in an initial cohort of 18 healthy participants. The task protocol was then implemented at 6 other imaging centers using identical methods. Data from a second cohort of participants scanned at these centers closely replicated the results from the initial cohort. The Story-Math protocol provides a reliable method for activation of surgical regions of interest in the ATL. The bilateral activation supports previous claims that conceptual processing involves both temporal lobes. Used in combination with language lateralization measures, reliable ATL activation maps may be useful for predicting cognitive outcome in ATL surgery, though the validity of this approach needs to be established in a prospective surgical series. PMID:20884358

Understanding and Harnessing the Power of the Cohort Model in Preparing Educational Leaders.

ERIC Educational Resources Information Center

Teitel, Lee

1997-01-01

The University of Massachusetts at Boston (UMB) shifted all of its school leadership programs to the cohort model. This article reviews UMB's school leadership programs, describes the survey methodology used to take stock of the program and its cohort design, then summarizes survey findings to identify five different types of impacts reported by…

Social cohesion through football: a quasi-experimental mixed methods design to evaluate a complex health promotion program

PubMed Central

2010-01-01

Social isolation and disengagement fragments local communities. Evidence indicates that refugee families are highly vulnerable to social isolation in their countries of resettlement. Research to identify approaches to best address this is needed. Football United is a program that aims to foster social inclusion and cohesion in areas with high refugee settlement in New South Wales, Australia, through skills and leadership development, mentoring, and the creation of links with local community and corporate leaders and organisations. The Social Cohesion through Football study's broad goal is to examine the implementation of a complex health promotion program, and to analyse the processes involved in program implementation. The study will consider program impact on individual health and wellbeing, social inclusion and cohesion, as well as analyse how the program by necessity interacts and adapts to context during implementation, a concept we refer to as plasticity. The proposed study will be the first prospective cohort impact study to our knowledge to assess the impact of a comprehensive integrated program using football as a vehicle for fostering social inclusion and cohesion in communities with high refugee settlement. Methods/design A quasi-experimental cohort study design with treatment partitioning involving four study sites. The study employs a 'dose response' model, comparing those with no involvement in the Football United program with those with lower or higher levels of participation. A range of qualitative and quantitative measures will be used in the study. Study participants' emotional well being, resilience, ethnic identity and other group orientation, feelings of social inclusion and belonging will be measured using a survey instrument complemented by relevant data drawn from in-depth interviews, self reporting measures and participant observation. The views of key informants from the program and the wider community will also be solicited. Discussion The complexity of the Football United program poses challenges for measurement, and requires the study design to be responsive to the dynamic nature of the program and context. Assessment of change is needed at multiple levels, drawing on mixed methods and multidisciplinary approaches in implementation and evaluation. Attention to these challenges has underpinned the design and methods in the Social Cohesion through Football study, which will use a unique and innovative combination of measures that have not been applied together previously in social inclusion/cohesion and sport and social inclusion/cohesion program research. PMID:20920361

The Fender Stratocaster Electric Guitar: A Case Study for both Nontransferable and Transferable Skills Learning in a Generalist Electronic Engineering Cohort

ERIC Educational Resources Information Center

Joyce, M. J.

2010-01-01

A case-study approach to teaching electronics system design that has been used since 2004 to demonstrate the importance of both nontransferable and transferable design issues to first-year undergraduate students is described. The student cohort of relevance to this work represents a diverse group comprising both students studying for a four-year…

The Study of the Prevention of Anal Cancer (SPANC): design and methods of a three-year prospective cohort study

PubMed Central

2013-01-01

Background The incidence of human papillomavirus (HPV)-associated anal cancer is increasing in men who have sex with men (MSM). Screening for the presumed cancer precursor, high-grade anal squamous intraepithelial lesions (HSIL) in a manner analogous to cervical cancer screening has been proposed. Uncertainty remains regarding anal HPV natural history and the role of anal cytology and high-resolution anoscopy (HRA) as screening tests. Well-designed cohort studies are required to address these issues. Methods/design The SPANC study is a prospective study of the epidemiology of low-risk and high-risk anal HPV infection and related cytological and histological abnormalities in HIV-negative and HIV-positive homosexual men aged 35 years and over. The study aims to recruit 600 men from community-based settings in Sydney, Australia. There are six study visits over three years. At the first five visits men undergo a digital ano-rectal examination (DARE), an anal “Papanicolaou” (Pap) test for HPV detection, genotyping and anal cytology, followed by HRA and directed biopsy of any visible abnormalities. The men also complete a behavioural questionnaire before each visit. Questions include a detailed history of sexual behaviour, of anal symptoms, possible anal cancer risk factors and validated quality of life and psychosocial questions. Questionnaires are also completed 2 weeks and 3 months following the provision of test results and include questions on participant experience during the procedure and post-procedure symptoms, including pain and bleeding in addition to quality of life/ psychosocial outcomes. Discussion Recruitment for the study began in September 2010 and will conclude in mid-2015, with follow up continuing to 2018. Thus far, over 350 men have been recruited from a variety of community-based settings and are broadly representative of the target screening population. The SPANC study is one of only a small number of cohort studies globally to perform HPV, cytology and HRA screening on all participants over multiple time points. The study results will contribute to understanding of the natural history of anal HPV and inform the possible development of guidelines for implementing anal cancer screening programs in this population. PMID:24107134

A tangled web: Interactions and structures in university-school collaborations

NASA Astrophysics Data System (ADS)

Ohana, Christina Pickerell

1999-10-01

In this volume, I examine some of the structures and beliefs embedded in a university-school partnership. I try to untangle the complex web of interests, ideologies, and information that participants bring to the project. This dissertation includes three research papers. In the first paper, "Integration of Theory with Practice: A Comparison of Two Science Methods Courses," I studied the work of students in two science methods courses. One class was a preservice cohort involved in an experimental program with significant levels of field experiences. Their work was compared to students in the regular program who have a modest field component. In this analysis, cohort students made many more references to field placements than students in the regular program. Cohort students also used peers as sources of information and authority. Students in the regular program used sources from university coursework to help them interpret field experiences. They rarely mentioned peers. These differences were interpreted in light of their meaning for efforts to improve teacher education. In the second paper, "Preservice Cohorts and their Implications for Mathematics and Science Education," I surveyed the literature on cohorts in preservice teacher education. I described the structure of three preservice programs at different universities that have mathematics- or science-focused preservice cohorts. While some progress is apparent, there are many areas which were unaffected by the new structure. There are also effects that may be undesirable. Both the literature and site visits highlighted the need for program developers in teacher education to attend to both design and purpose. In the final paper, "Interests, Ideology, Information, and Institutions in a University-School Partnership," I examined the programs from a broader perspective. I used a model of interests, ideology, information, and institution (the "4 I's,") to examine how university-school partnerships link two very complex institutions. I found that in order for the two institutions to work together, they must accommodate the interests, ideology, and information of the other. This accommodation allowed the two organizations to work together but prevents more fundamental change.

Current estimates of the cure fraction: a feasibility study of statistical cure for breast and colorectal cancer.

PubMed

Stedman, Margaret R; Feuer, Eric J; Mariotto, Angela B

2014-11-01

The probability of cure is a long-term prognostic measure of cancer survival. Estimates of the cure fraction, the proportion of patients "cured" of the disease, are based on extrapolating survival models beyond the range of data. The objective of this work is to evaluate the sensitivity of cure fraction estimates to model choice and study design. Data were obtained from the Surveillance, Epidemiology, and End Results (SEER)-9 registries to construct a cohort of breast and colorectal cancer patients diagnosed from 1975 to 1985. In a sensitivity analysis, cure fraction estimates are compared from different study designs with short- and long-term follow-up. Methods tested include: cause-specific and relative survival, parametric mixture, and flexible models. In a separate analysis, estimates are projected for 2008 diagnoses using study designs including the full cohort (1975-2008 diagnoses) and restricted to recent diagnoses (1998-2008) with follow-up to 2009. We show that flexible models often provide higher estimates of the cure fraction compared to parametric mixture models. Log normal models generate lower estimates than Weibull parametric models. In general, 12 years is enough follow-up time to estimate the cure fraction for regional and distant stage colorectal cancer but not for breast cancer. 2008 colorectal cure projections show a 15% increase in the cure fraction since 1985. Estimates of the cure fraction are model and study design dependent. It is best to compare results from multiple models and examine model fit to determine the reliability of the estimate. Early-stage cancers are sensitive to survival type and follow-up time because of their longer survival. More flexible models are susceptible to slight fluctuations in the shape of the survival curve which can influence the stability of the estimate; however, stability may be improved by lengthening follow-up and restricting the cohort to reduce heterogeneity in the data. Published by Oxford University Press 2014.

Modular design, application architecture, and usage of a self-service model for enterprise data delivery: the Duke Enterprise Data Unified Content Explorer (DEDUCE).

PubMed

Horvath, Monica M; Rusincovitch, Shelley A; Brinson, Stephanie; Shang, Howard C; Evans, Steve; Ferranti, Jeffrey M

2014-12-01

Data generated in the care of patients are widely used to support clinical research and quality improvement, which has hastened the development of self-service query tools. User interface design for such tools, execution of query activity, and underlying application architecture have not been widely reported, and existing tools reflect a wide heterogeneity of methods and technical frameworks. We describe the design, application architecture, and use of a self-service model for enterprise data delivery within Duke Medicine. Our query platform, the Duke Enterprise Data Unified Content Explorer (DEDUCE), supports enhanced data exploration, cohort identification, and data extraction from our enterprise data warehouse (EDW) using a series of modular environments that interact with a central keystone module, Cohort Manager (CM). A data-driven application architecture is implemented through three components: an application data dictionary, the concept of "smart dimensions", and dynamically-generated user interfaces. DEDUCE CM allows flexible hierarchies of EDW queries within a grid-like workspace. A cohort "join" functionality allows switching between filters based on criteria occurring within or across patient encounters. To date, 674 users have been trained and activated in DEDUCE, and logon activity shows a steady increase, with variability between months. A comparison of filter conditions and export criteria shows that these activities have different patterns of usage across subject areas. Organizations with sophisticated EDWs may find that users benefit from development of advanced query functionality, complimentary to the user interfaces and infrastructure used in other well-published models. Driven by its EDW context, the DEDUCE application architecture was also designed to be responsive to source data and to allow modification through alterations in metadata rather than programming, allowing an agile response to source system changes. Copyright © 2014 Elsevier Inc. All rights reserved.

Growth rates of young-of-year shovelnose sturgeon in the Upper Missouri River

USGS Publications Warehouse

Braaten, P. J.; Fuller, D.B.

2007-01-01

Information on growth during the larval and young-of-year life stages in natural river environments is generally lacking for most sturgeon species. In this study, methods for estimating ages and quantifying growth were developed for field-sampled larval and young-of-year shovelnose sturgeon Scaphirhynchus platorynchus in the upper Missouri River. First, growth was assessed by partitioning samples of young-of-year shovelnose sturgeon into cohorts, and regressing weekly increases in cohort mean length on sampling date. This method quantified relative growth because ages of the cohorts were unknown. Cohort increases in mean length among sampling dates were positively related (P < 0.05, r2 > 0.59 for all cohorts) to sampling date, and yielded growth rate estimates of 0.80–2.95 mm day−1 (2003) and 0.44–2.28 mm day−1 (2004). Highest growth rates occurred in the largest (and earliest spawned) cohorts. Second, a method was developed to estimate cohort hatch dates, thus age on date of sampling could be determined. This method included quantification of post-hatch length increases as a function of water temperature (growth capacity; mm per thermal unit, mm TU−1), and summation of mean daily water temperatures to achieve the required number of thermal units that corresponded to post-hatch lengths of shovelnose sturgeon on sampling dates. For six of seven cohorts of shovelnose sturgeon analyzed, linear growth models (r2 ≥ 0.65, P < 0.0001) or Gompertz growth models (r2 ≥ 0.83, P < 0.0001) quantified length-at-age from hatch through 55 days post-hatch (98–100 mm). Comparisons of length-at-age derived from the growth models indicated that length-at-age was greater for the earlier-hatched cohorts than later-hatched cohorts. Estimated hatch dates for different cohorts were corroborated based on the dates that newly-hatched larval shovelnose sturgeon were sampled in the drift. These results provide the first quantification of growth dynamics for field-sampled age-0 shovelnose sturgeon in a natural river environment, and provide an accurate method for estimating age of wild-caught individuals. Methods of age determination used in this study have applications to sturgeons in other regions, but require additional testing and validation.

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.

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

Design innovations and baseline findings in a long-term Parkinson’s trial: NET-PD LS-1

PubMed Central

2012-01-01

Background Based on the pre-clinical and the results of a phase 2 futility study, creatine was selected for an efficacy trial in Parkinson’s disease (PD). We present the design rationale and a description of the study cohort at baseline. Methods A randomized, multicenter, double-blind, parallel group, placebo controlled Phase 3 study of creatine (10 gm daily) in participants with early, treated PD, the Long-term Study – 1 (LS-1) is being conducted by the NINDS Exploratory Trials in Parkinson’s Disease (NET-PD) network. The study utilizes a global statistical test (GST) encompassing multiple clinical rating scales to provide a multidimensional assessment of disease progression. Results A total of 1,741 PD participants from 45 sites in the U.S. and Canada were randomized 1:1 to either 10-gm creatine/day or matching placebo. Participants are being evaluated for a minimum of 5 years. The LS-1 baseline cohort includes participants treated with dopaminergic therapy and generally mild PD. Conclusions LS-1 represents the largest cohort of patients with early treated PD ever enrolled in a clinical trial. The GST approach should provide high power to test the hypothesis that daily administration of creatine (10gm/day) is more effective than placebo in slowing clinical decline in PD between baseline and the 5 year follow-up visit against the background of dopaminergic therapy and best PD care. PMID:23079770

Service-Learning Enhances Physical Therapy Students' Ability to Examine Fall Risk in Older Adults.

PubMed

Nordon-Craft, Amy; Schwarz, Brandy; Kowalewski, Victoria; Hartos, Jessica; Jurado Severance, Jennifer; Bugnariu, Nicoleta

2017-01-01

Service-learning (SL) is one educational methodology that provides students opportunities to practice and refine affective, cognitive and psychomotor skills in a community-based setting. The aims of this study were: 1) to investigate the impact of SL on physical therapy (PT) students' attitudes and perceived clinical competence when working with older adults, and 2) to evaluate the difference between perceptions of students who developed and implemented the SL activity vs those who implemented only. Eighty PT students, (from two consecutive cohorts) enrolled in a first-year geriatrics course, participated in this study. The first cohort designed and implemented the SL activities, while the second cohort only implemented these activities. Student self-perceived anxiety, confidence, knowledge and skills were assessed by pre- and post-SL surveys using a 5- point Likert-like scale. Both cohorts reported similar anxiety and confidence levels pre-SL. For both cohorts, with the exception of one item, all responses to anxiety items significantly decreased from pre- to post-SL. All students' confidence levels for assessing and mitigating fall risk in older adults increased post-SL (p<0.01). Moreover, students in cohort 1, who designed and delivered SL activities, expressed self-perceived improvement in their ability to interpret results of evaluations, to determine type and severity of balance impairments, and to serve a geriatric population (p<0.05) compared to students in cohort 2 who only implemented the activities. Embedding SL into a geriatrics course decreased self-perceived anxiety and improved student confidence regarding working with older adults. Also, empowering students to be actively involved in the design and implementation of SL increased self-perceived ability in interpreting results from assessments.

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

Prevalence rates for dementia and Alzheimer’s disease in African Americans: 1992 vs. 2001

PubMed Central

Hall, KS; Gao, S; Baiyewu, O; Lane, KA; Gureje, O; Shen, J; Ogunniyi, A; Murrell, JR; Unverzagt, FW; Dickens, J; Smith-Gamble, V; Hendrie, HC

2009-01-01

Background This study compares age-specific and overall prevalence rates for dementia and Alzheimer’s disease (AD) in two non overlapping population-based cohorts of elderly African Americans in Indianapolis in 2001 and 1992. Methods Two-stage design, first stage is Community Screening Interview for Dementia (CSI-D). CSI-D scores grouped into good, intermediate and poor performance for selection into clinical assessment. Diagnosis was made using standard criteria in consensus diagnosis conference; clinicians blind to performance group. In 1992, interviewers went to randomly sampled addresses enrolling self identified African Americans age ≥ 65; of 2,582 eligible, 2,212 enrolled, (9.6% refused, 4.7% too sick). In 2001, Medicare roles were used for African Americans age ≥ 70 years; of 4,260 eligible, 1,892 (44%) enrolled, 1,999 (47%) refused, the remainder had other reasons. Results The overall age adjusted prevalence rate for dementia for age ≥ 70 years in 2001 was 7.45% (95 confidence interval [CI] 4.27–10.64) and for the 1992 cohort was 6.75% (95% CI 5.77–7.74). The overall age adjusted prevalence rate for age ≥ 70 years, for AD for the 2001 cohort was 6.77% (95% CI 3.65–9.90), and for the 1992 cohort was 5.47% (95% CI 4.51–6.42). Rates for dementia and AD were not significantly different in the two cohorts (dementia, p=0.3534, AD, p=0.2649). Conclusions We find no differences in prevalence rates of dementia and AD between 1992 and 2001 in spite of significant medical history and medical treatment differences in these population-based cohorts of African American elderly. PMID:19426950

Derivation and Validation of a Renal Risk Score for People With Type 2 Diabetes

PubMed Central

Elley, C. Raina; Robinson, Tom; Moyes, Simon A.; Kenealy, Tim; Collins, John; Robinson, Elizabeth; Orr-Walker, Brandon; Drury, Paul L.

2013-01-01

OBJECTIVE Diabetes has become the leading cause of end-stage renal disease (ESRD). Renal risk stratification could assist in earlier identification and targeted prevention. This study aimed to derive risk models to predict ESRD events in type 2 diabetes in primary care. RESEARCH DESIGN AND METHODS The nationwide derivation cohort included adults with type 2 diabetes from the New Zealand Diabetes Cohort Study initially assessed during 2000–2006 and followed until December 2010, excluding those with pre-existing ESRD. The outcome was fatal or nonfatal ESRD event (peritoneal dialysis or hemodialysis for ESRD, renal transplantation, or death from ESRD). Risk models were developed using Cox proportional hazards models, and their performance was assessed in a separate validation cohort. RESULTS The derivation cohort included 25,736 individuals followed for up to 11 years (180,497 person-years; 86% followed for ≥5 years). At baseline, mean age was 62 years, median diabetes duration 5 years, and median HbA1c 7.2% (55 mmol/mol); 37% had albuminuria; and median estimated glomerular filtration rate (eGFR) was 77 mL/min/1.73 m2. There were 637 ESRD events (2.5%) during follow-up. Models that included sex, ethnicity, age, diabetes duration, albuminuria, serum creatinine, systolic blood pressure, HbA1c, smoking status, and previous cardiovascular disease status performed well with good discrimination and calibration in the derivation cohort and the validation cohort (n = 5,877) (C-statistics 0.89–0.92), improving predictive performance compared with previous models. CONCLUSIONS These 5-year renal risk models performed very well in two large primary care populations with type 2 diabetes. More accurate risk stratification could facilitate earlier intervention than using eGFR and/or albuminuria alone. PMID:23801726

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.

Risk of Pneumonia with Inhaled Corticosteroid versus Long-Acting Bronchodilator Regimens in Chronic Obstructive Pulmonary Disease: A New-User Cohort Study

PubMed Central

DiSantostefano, Rachael L.; Sampson, Tim; Le, Hoa Van; Hinds, David; Davis, Kourtney J.; Bakerly, Nawar Diar

2014-01-01

Introduction Observational studies using case-control designs have showed an increased risk of pneumonia associated with inhaled corticosteroid (ICS)-containing medications in patients with chronic obstructive pulmonary disease (COPD). New-user observational cohort designs may minimize biases associated with previous case-control designs. Objective To estimate the association between ICS and pneumonia among new users of ICS relative to inhaled long-acting bronchodilator (LABD) monotherapy. Methods Pneumonia events in COPD patients ≥45 years old were compared among new users of ICS medications (n = 11,555; ICS, ICS/long-acting β2-agonist [LABA] combination) and inhaled LABD monotherapies (n = 6,492; LABA, long-acting muscarinic antagonists) using Cox proportional hazards models, with propensity scores to adjust for confounding. Setting: United Kingdom electronic medical records with linked hospitalization and mortality data (2002–2010). New users were censored at earliest of: pneumonia event, death, changing/discontinuing treatment, or end of follow-up. Outcomes: severe pneumonia (primary) and any pneumonia (secondary). Results Following adjustment, new use of ICS-containing medications was associated with an increased risk of pneumonia hospitalization (n = 322 events; HR = 1.55, 95% CI: 1.14, 2.10) and any pneumonia (n = 702 events; HR = 1.49, 95% CI: 1.22, 1.83). Crude incidence rates of any pneumonia were 48.7 and 30.9 per 1000 person years among the ICS-containing and LABD cohorts, respectively. Excess risk of pneumonia with ICS was reduced when requiring ≥1 month or ≥ 6 months of new use. There was an apparent dose-related effect, with greater risk at higher daily doses of ICS. There was evidence of channeling bias, with more severe patients prescribed ICS, for which the analysis may not have completely adjusted. Conclusions The results of this new-user cohort study are consistent with published findings; ICS were associated with a 20–50% increased risk of pneumonia in COPD, which reduced with exposure time. This risk must be weighed against the benefits when prescribing ICS to patients with COPD. PMID:24878543

A follow-up study of heroin addicts (VEdeTTE2): study design and protocol

PubMed Central

Vigna-Taglianti, Federica D; Mathis, Federica; Diecidue, Roberto; Burroni, Paola; Iannaccone, Antonio; Lampis, Fabio; Zuccaro, Piergiorgio; Pacifici, Roberta; Versino, Elisabetta; Davoli, Marina; Faggiano, Fabrizio

2007-01-01

Background In Italy, a large cohort study (VEdeTTE1) was conducted between 1998–2001 to evaluate the effectiveness of treatments in reducing mortality and increasing treatment retention among heroin addicts. The follow-up of this cohort (VEdeTTE2) was designed to evaluate the effectiveness of treatments on long-term outcomes, such as rehabilitation and social re-integration. The purpose of this paper is to describe the protocol of the VEdeTTE2 study, and to present the results of the pilot study carried out to assess the feasibility of the study and to improve study procedures. Methods The source population for the VEdeTTE2 study was the VEdeTTE1 cohort, from which a sample of 2,200 patients, traced two or more years after enrolment in the cohort, were asked to participate. An interview investigates drug use; overdose; family and social re-integration. Illegal activity are investigated separately in a questionnaire completed by the patient. Patients are also asked to provide a hair sample to test for heroin and cocaine use. Information on treatments and HIV, HBV and HCV morbidity are obtained from clinical records. A pilot phase was planned and carried out on 60 patients. Results The results of the pilot phase pointed out the validity of the procedures designed to limit attrition: the number of traced subjects was satisfactory (88%). Moreover, the pilot phase was very useful in identifying possible causes of delays and attrition, and flaws in the instruments. Improvements to the procedures and the instruments were subsequently implemented. Sensitivity of the biological test was quite good for heroin (78%) but lower for cocaine (42.3%), highlighting the need to obtain a hair sample from all patients. Conclusion In drug addiction research, studies investigating health status and social re-integration of subjects at long-term follow-up are lacking. The VEdeTTE2 study aims to investigate these outcomes at long-term follow-up. Results of the pilot phase underline the importance of the pilot phase when planning a follow-up study. PMID:17362515

A novel method to value real options in health care: the case of a multicohort human papillomavirus vaccination strategy.

PubMed

Favato, Giampiero; Baio, Gianluca; Capone, Alessandro; Marcellusi, Andrea; Saverio Mennini, Francesco

2013-07-01

A large number of economic evaluations have already confirmed the cost-effectiveness of different human papillomavirus (HPV) vaccination strategies. Standard analyses might not capture the full economic value of novel vaccination programs because the cost-effectiveness paradigm fails to take into account the value of active management. Management decisions can be seen as real options, a term used to refer to the application of option pricing theory to the valuation of investments in nonfinancial assets in which much of the value is attributable to flexibility and learning over time. The aim of this article was to discuss the potential advantages shown by using the payoff method in the valuation of the cost-effectiveness of competing HPV immunization programs. This was the first study, to the best of our knowledge, to use the payoff method to determine the real option values of 4 different HPV vaccination strategies targeting female subjects aged 12, 15, 18, and 25 years. The payoff method derives the real option value from the triangular payoff distribution of the project's net present value, which is treated as a triangular fuzzy number. To inform the real option model, cost-effectiveness data were derived from an empirically calibrated Bayesian model designed to assess the cost-effectiveness of a multicohort HPV vaccination strategy in the context of the current cervical cancer screening program in Italy. A net health benefit approach was used to calculate the expected fuzzy net present value for each of the 4 vaccination strategies evaluated. Costs per quality-adjusted life-year gained seemed to be related to the number of cohorts targeted: a single cohort of girls aged 12 years (€10,955 [95% CI, -1,021 to 28,212]) revealed the lowest cost among the 4 alternative strategies evaluated. The real option valuation challenged the cost-effectiveness dominance of a single cohort of 12-year-old girls. The simultaneous vaccination of 2 cohorts of girls aged 12 and 15 years yielded a real option value (€17,723) equivalent to that attributed to a single cohort of 12-year-old girls (€17,460). The payoff method showed distinctive advantages in the valuation of the cost-effectiveness of competing health care interventions, essentially determined by the replacement of the nonfuzzy numbers that are commonly used in cost-effectiveness analysis models, with fuzzy numbers as an input to inform the real option pricing method. The real option approach to value uncertainty makes policy making in health care an evolutionary process and creates a new "space" for decision-making choices. Copyright © 2013 Elsevier HS Journals, Inc. All rights reserved.

The Trend-in-trend Research Design for Causal Inference.

PubMed

Ji, Xinyao; Small, Dylan S; Leonard, Charles E; Hennessy, Sean

2017-07-01

Cohort studies can be biased by unmeasured confounding. We propose a hybrid ecologic-epidemiologic design called the trend-in-trend design, which requires a strong time trend in exposure, but is unbiased unless there are unmeasured factors affecting outcome for which there are time trends in prevalence that are correlated with time trends in exposure across strata with different exposure trends. Thus, the conditions under which the trend-in-trend study is biased are a subset of those under which a cohort study is biased. The trend-in-trend design first divides the study population into strata based on the cumulative probability of exposure given covariates, which effectively stratifies on time trend in exposure, provided there is a trend. Next, a covariates-free maximum likelihood model estimates the odds ratio (OR) using data on exposure prevalence and outcome frequency within cumulative probability of exposure strata, across multiple periods. In simulations, the trend-in-trend design produced ORs with negligible bias in the presence of unmeasured confounding. In empiric applications, trend-in-trend reproduced the known positive association between rofecoxib and myocardial infarction (observed OR: 1.2, 95% confidence interval: 1.1, 1.4), and known null associations between rofecoxib and severe hypoglycemia (OR = 1.1 [0.92, 1.3]) and nonvertebral fracture (OR = 0.84 [0.64, 1.1]). The trend-in-trend method may be useful in settings where there is a strong time trend in exposure, such as a newly approved drug or other medical intervention. See video abstract at, http://links.lww.com/EDE/B178.

Lung cancer mortality in North Carolina and South Carolina chrysotile asbestos textile workers.

PubMed

Elliott, Leslie; Loomis, Dana; Dement, John; Hein, Misty J; Richardson, David; Stayner, Leslie

2012-06-01

Studies of workers in two US cohorts of asbestos textile workers exposed to chrysotile (North Carolina (NC) and South Carolina (SC)) found increasing risk of lung cancer mortality with cumulative fibre exposure. However, the risk appeared to increase more steeply in SC, possibly due to differences in study methods. The authors conducted pooled analyses of the cohorts and investigated the exposure-disease relationship using uniform cohort inclusion criteria and statistical methods. Workers were included after 30 days of employment in a production job during qualifying years, and vital status ascertained through 2003 (2001 for SC). Poisson regression was used to estimate the exposure-response relationship between asbestos and lung cancer, using both exponential and linear relative rate models adjusted for age, sex, race, birth cohort and decade of follow-up. The cohort included 6136 workers, contributing 218,631 person-years of observation and 3356 deaths. Cumulative exposures at the four study facilities varied considerably. The pooled relative rate for lung cancer, comparing 100 f-yr/ml to 0 f-yr/ml, was 1.11 (95% CI 1.06 to 1.16) for the combined cohort, with different effects in the NC cohort (RR=1.10, 95% CI 1.03 to 1.16) and the SC cohort (RR = 1.67, 95% CI 1.44 to 1.93). Increased rates of lung cancer were significantly associated with cumulative fibre exposure overall and in both the Carolina asbestos-textile cohorts. Previously reported differences in exposure-response between the cohorts do not appear to be related to inclusion criteria or analytical methods.

42 CFR 83.17 - How will the Secretary report a final decision to add a class of employees to the Cohort and any...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Secretary report a final decision to add a class of employees to the Cohort and any action of Congress... to the Cohort, the Secretary will transmit to Congress a report providing the designation, the... as defined by the Board, then the Secretary will transmit to Congress the report specified in...

42 CFR 83.17 - How will the Secretary report a final decision to add a class of employees to the Cohort and any...

Code of Federal Regulations, 2011 CFR

2011-10-01

... Secretary report a final decision to add a class of employees to the Cohort and any action of Congress... to the Cohort, the Secretary will transmit to Congress a report providing the designation, the... as defined by the Board, then the Secretary will transmit to Congress the report specified in...

42 CFR 83.17 - How will the Secretary report a final decision to add a class of employees to the Cohort and any...

Code of Federal Regulations, 2014 CFR

2014-10-01

... Secretary report a final decision to add a class of employees to the Cohort and any action of Congress... to the Cohort, the Secretary will transmit to Congress a report providing the designation, the... as defined by the Board, then the Secretary will transmit to Congress the report specified in...

42 CFR 83.17 - How will the Secretary report a final decision to add a class of employees to the Cohort and any...

Code of Federal Regulations, 2010 CFR

2010-10-01

... Secretary report a final decision to add a class of employees to the Cohort and any action of Congress... to the Cohort, the Secretary will transmit to Congress a report providing the designation, the... as defined by the Board, then the Secretary will transmit to Congress the report specified in...

42 CFR 83.17 - How will the Secretary report a final decision to add a class of employees to the Cohort and any...

Code of Federal Regulations, 2013 CFR

2013-10-01

... Secretary report a final decision to add a class of employees to the Cohort and any action of Congress... to the Cohort, the Secretary will transmit to Congress a report providing the designation, the... as defined by the Board, then the Secretary will transmit to Congress the report specified in...

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/.

Risk factors and study designs used in research of youths' suicide behaviour-an epidemiological discussion with focus on level of evidence.

PubMed

Christiansen, Erik; Larsen, Kim Juul; Agerbo, Esben; Bilenberg, Niels; Stenager, Elsebeth

2014-11-01

Abstract Introduction: Many different epidemiology study designs have been used to analyse risk factors for suicide behaviour. The purpose of this study was to obtain an insight into the current study design used in research on youths' risk factors for suicide behaviour and to rank the studies according to level of evidence (LoE). We searched PubMed and psycINFO in order to identify relevant individual studies. We included 36 studies of children and youth on suicidal behaviour and ideation-many rank low on LoE. For suicide, cohort design was often used, and mental illness (depression, substance abuse and severity of mental illness) was the most common risk factor. Cohort studies are ranked 2b, which is high according to LoE. For suicide attempts, survey was often used, and psychopathology, substance abuse and being exposed to suicidal behaviour were the most common risk factors. For suicidal ideation, survey was the only design used, and substance abuse and psychopathology the most common risk factors. Surveys are ranked 4, which are low according to LoE. Many risk factors were broad and unspecific, and standard definitions of outcome and exposure were rarely used. A good study of risk factors for suicidal behaviour would need a high LoE, as a high-powered longitudinal epidemiological study (cohort or case-control) of very specific risk factors. The factors would have high prevention potential, compared with more broad and unspecific risk factors, to which many people are exposed. We would recommend a cohort design (in high-risk populations) or a case-control design to identify risk factors, using clinical and/or register data instead of self-reported information, reporting adjusted estimates and using standard definition of suicidal outcome and risk factors.

CARRS Surveillance study: design and methods to assess burdens from multiple perspectives

PubMed Central

2012-01-01

Background Cardio-metabolic diseases (CMDs) are a growing public health problem, but data on incidence, trends, and costs in developing countries is scarce. Comprehensive and standardised surveillance for non-communicable diseases was recommended at the United Nations High-level meeting in 2011. Aims: To develop a model surveillance system for CMDs and risk factors that could be adopted for continued assessment of burdens from multiple perspectives in South-Asian countries. Methods Design: Hybrid model with two cross-sectional serial surveys three years apart to monitor trend, with a three-year prospective follow-up of the first cohort. Sites: Three urban settings (Chennai and New Delhi in India; Karachi in Pakistan), 4000 participants in each site stratified by gender and age. Sampling methodology: Multi-stage cluster random sampling; followed by within-household participant selection through a combination of Health Information National Trends Study (HINTS) and Kish methods. Culturally-appropriate and methodologically-relevant data collection instruments were developed to gather information on CMDs and their risk factors; quality of life, health-care utilisation and costs, along with objective measures of anthropometric, clinical and biochemical parameters. The cohort follow-up is designed as a pilot study to understand the feasibility of estimating incidence of risk factors, disease events, morbidity, and mortality. Results The overall participant response rate in the first cross-sectional survey was 94.1% (Chennai 92.4%, n = 4943; Delhi 95.7%, n = 4425; Karachi 94.3%, n = 4016). 51.8% of the participants were females, 61.6% < 45years, 27.5% 45–60years and 10.9% >60 years. Discussion This surveillance model will generate data on prevalence and trends; help study the complex life-course patterns of CMDs, and provide a platform for developing and testing interventions and tools for prevention and control of CMDs in South-Asia. It will also help understanding the challenges and opportunities in establishing a surveillance system across countries. PMID:22928740

Uranium and other natural radionuclides in drinking water and risk of leukemia: a case-cohort study in Finland.

PubMed

Auvinen, Anssi; Kurttio, Päivi; Pekkanen, Juha; Pukkala, Eero; Ilus, Taina; Salonen, Laina

2002-11-01

We assessed the effect of natural uranium and other radionuclides in drinking water on risk of leukemia. The subjects (n = 144,627) in the base cohort had lived outside the municipal tapwater system during 1967-1980. A subcohort was formed as a stratified random sample of the base cohort and subjects using drinking water from drilled wells prior to 1981 were identified. A case-cohort design was used comparing exposure among cases with leukemia (n = 35) with a stratified random sample (n = 274) from the subcohort. Activity concentrations of uranium, radium-226, and radon in the drinking water were analyzed using radiochemical and alpha-spectrometric methods. The median activity concentration of uranium in well water was 0.08 Bq/L for the leukemia cases and 0.06 Bq/L for the reference group, radon concentrations 80 and 130 Bq/L, respectively, and radium-226 concentrations 0.01 Bq/L for both groups. The hazard ratio of leukemia for uranium was 0.91 (95% confidence interval 0.73-1.13) per Bq/L. for radon 0.79 per Bq/L (95% CI 0.27-2.29), and for radium-226 0.80 (95% CI 0.46-1.39) per Bq/L. Our results do not indicate an increased risk of leukemia from ingestion of natural uranium or other radionuclides through drinking water at these exposure levels.

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

Rationale of the FIBROTARGETS study designed to identify novel biomarkers of myocardial fibrosis

PubMed Central

Ferreira, João Pedro; Machu, Jean‐Loup; Girerd, Nicolas; Jaisser, Frederic; Thum, Thomas; Butler, Javed; González, Arantxa; Diez, Javier; Heymans, Stephane; McDonald, Kenneth; Gyöngyösi, Mariann; Firat, Hueseyin; Rossignol, Patrick; Pizard, Anne

2017-01-01

Abstract Aims Myocardial fibrosis alters the cardiac architecture favouring the development of cardiac dysfunction, including arrhythmias and heart failure. Reducing myocardial fibrosis may improve outcomes through the targeted diagnosis and treatment of emerging fibrotic pathways. The European‐Commission‐funded ‘FIBROTARGETS’ is a multinational academic and industrial consortium with the main aims of (i) characterizing novel key mechanistic pathways involved in the metabolism of fibrillary collagen that may serve as biotargets, (ii) evaluating the potential anti‐fibrotic properties of novel or repurposed molecules interfering with the newly identified biotargets, and (iii) characterizing bioprofiles based on distinct mechanistic phenotypes involving the aforementioned biotargets. These pathways will be explored by performing a systematic and collaborative search for mechanisms and targets of myocardial fibrosis. These mechanisms will then be translated into individualized diagnostic tools and specific therapeutic pharmacological options for heart failure. Methods and results The FIBROTARGETS consortium has merged data from 12 patient cohorts in a common database available to individual consortium partners. The database consists of >12 000 patients with a large spectrum of cardiovascular clinical phenotypes. It integrates community‐based population cohorts, cardiovascular risk cohorts, and heart failure cohorts. Conclusions The FIBROTARGETS biomarker programme is aimed at exploring fibrotic pathways allowing the bioprofiling of patients into specific ‘fibrotic’ phenotypes and identifying new therapeutic targets that will potentially enable the development of novel and tailored anti‐fibrotic therapies for heart failure. PMID:28988439

Education in Care and Technology; Development and Evaluation of a First Cohort of an International Master Course.

PubMed

Willems, Charles G

2017-01-01

A report written as a personal communication based on the experience gathered by developing and delivery of a international professional master course. The organization of the curriculum consists of 16 modules. Using a framework of the user centered design and development cycle students receive domain knowledge related to user-orientation, business, innovation and implementation. Also, introduction is given to tools that can be used to investigate certain aspects. The course will be completed by the performance of master thesis research related of a practice oriented problem relevant to the work environment of the student. This master-course has been followed by a first cohort of 8 students. In this report, an evaluation is given on this first delivery. Organization of this course is complicated by the marketing conditions that have to be used. Students and teachers are well supported by the distance based learning environment. The 16 modules representing the content of the course contains a variety of subjects and methods and represents a huge educational load to the students. Translating this content to the development of the own applied research subject contributes to the learning process. The first cohort of students will complete their master thesis in July 2017. Further introduction of new cohorts will mainly depend on the possibility to reduce the financial constraints to participation.

Early Childhood Longitudinal Study, Birth Cohort (ECLS-B): Methodology Report for the 9-Month Data Collection (2001-02). Volume 2: Sampling. NCES 2005-147

ERIC Educational Resources Information Center

Bethel, James; Green, James L.; Nord, Christine; Kalton, Graham; West, Jerry

2005-01-01

This report is Volume 2 of the methodology report that provides information about the development, design, and conduct of the 9-month data collection of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B). This volume begins with a brief overview of the ECLS-B, but focuses on the sample design, calculation of response rates, development…

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.

Indian chronic kidney disease study: Design and methods.

PubMed

Kumar, Vivek; Yadav, Ashok Kumar; Gang, Sishir; John, Oommen; Modi, Gopesh K; Ojha, Jai Prakash; Pandey, Rajendra; Parameswaran, Sreejith; Prasad, Narayan; Sahay, Manisha; Varughese, Santosh; Baid-Agarwal, Seema; Jha, Vivekanand

2017-04-01

The rate and factors that influence progression of chronic kidney disease (CKD) in developing countries like India are unknown. A pan-country prospective, observational cohort study is needed to address these knowledge gaps. The Indian Chronic Kidney Disease (ICKD) study will be a cohort study of approximately 5000 patients with mild to moderate CKD presenting to centres that represent different geographical regions in India. Time to 50% decline in baseline estimated glomerular filtration rate, need of renal replacement therapy or any new cardiovascular disease (CVD) event or death from CVD are the primary end points. This study will provide the opportunity to determine risk factors for CKD progression and development of CVD in Indian subjects and perform international comparisons to determine ethnic and geographical differences. A bio-repository will provide a chance to discover biomarkers and explore genetic risk factors. © 2016 Asian Pacific Society of Nephrology.

Premature death of adult adoptees: analyses of a case-cohort sample.

PubMed

Petersen, Liselotte; Andersen, Per Kragh; Sørensen, Thorkild I A

2005-05-01

Genetic and environmental influence on risk of premature death in adulthood was investigated by estimating the associations in total and cause-specific mortality of adult Danish adoptees and their biological and adoptive parents. Among all 14,425 non-familial adoptions formally granted in Denmark during the period 1924 through 1947, we selected the study population according to a case-cohort sampling design. As the case-control design, the case-cohort design has the advantage of economic data collection and little loss in statistical efficiency, but the case-cohort sample has the additional advantages that rate ratio estimates may be obtained, and re-use of the cohort sample in future studies of other outcomes is possible. Analyses were performed using Kalbfleisch and Lawless's estimator for hazard ratio, and robust estimation for variances. In the main analyses the sample was restricted to birth years of the adoptees 1924 and after, and age of transfer to the adoptive parents before 7 years, and age at death was restricted to 16 to 70 years. The results showed a higher mortality among adoptees, whose biological parents died in the age range of 16 to 70 years; this was significant for deaths from natural causes, vascular causes and all causes. No influence was seen from early death of adoptive parents, regardless of cause of death. (c) 2005 Wiley-Liss, Inc.

Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis.

PubMed

Bougma, Karim; Aboud, Frances E; Harding, Kimberly B; Marquis, Grace S

2013-04-22

Several reviews and meta-analyses have examined the effects of iodine on mental development. None focused on young children, so they were incomplete in summarizing the effects on this important age group. The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under. A systematic review of articles using Medline (1980-November 2011) was carried out. We organized studies according to four designs: (1) randomized controlled trial with iodine supplementation of mothers; (2) non-randomized trial with iodine supplementation of mothers and/or infants; (3) prospective cohort study stratified by pregnant women's iodine status; (4) prospective cohort study stratified by newborn iodine status. Average effect sizes for these four designs were 0.68 (2 RCT studies), 0.46 (8 non-RCT studies), 0.52 (9 cohort stratified by mothers' iodine status), and 0.54 (4 cohort stratified by infants' iodine status). This translates into 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children. Thus, regardless of study design, iodine deficiency had a substantial impact on mental development. Methodological concerns included weak study designs, the omission of important confounders, small sample sizes, the lack of cluster analyses, and the lack of separate analyses of verbal and non-verbal subtests. Quantifying more precisely the contribution of iodine deficiency to delayed mental development in young children requires more well-designed randomized controlled trials, including ones on the role of iodized salt.

Use of Multiple Metabolic and Genetic Markers to Improve the Prediction of Type 2 Diabetes: the EPIC-Potsdam Study

PubMed Central

Schulze, Matthias B.; Weikert, Cornelia; Pischon, Tobias; Bergmann, Manuela M.; Al-Hasani, Hadi; Schleicher, Erwin; Fritsche, Andreas; Häring, Hans-Ulrich; Boeing, Heiner; Joost, Hans-Georg

2009-01-01

OBJECTIVE We investigated whether metabolic biomarkers and single nucleotide polymorphisms (SNPs) improve diabetes prediction beyond age, anthropometry, and lifestyle risk factors. RESEARCH DESIGN AND METHODS A case-cohort study within a prospective study was designed. We randomly selected a subcohort (n = 2,500) from 26,444 participants, of whom 1,962 were diabetes free at baseline. Of the 801 incident type 2 diabetes cases identified in the cohort during 7 years of follow-up, 579 remained for analyses after exclusions. Prediction models were compared by receiver operatoring characteristic (ROC) curve and integrated discrimination improvement. RESULTS Case-control discrimination by the lifestyle characteristics (ROC-AUC: 0.8465) improved with plasma glucose (ROC-AUC: 0.8672, P < 0.001) and A1C (ROC-AUC: 0.8859, P < 0.001). ROC-AUC further improved with HDL cholesterol, triglycerides, γ-glutamyltransferase, and alanine aminotransferase (0.9000, P = 0.002). Twenty SNPs did not improve discrimination beyond these characteristics (P = 0.69). CONCLUSIONS Metabolic markers, but not genotyping for 20 diabetogenic SNPs, improve discrimination of incident type 2 diabetes beyond lifestyle risk factors. PMID:19720844

A pragmatic method for electronic medical record-based observational studies: developing an electronic medical records retrieval system for clinical research

PubMed Central

Yamamoto, Keiichi; Sumi, Eriko; Yamazaki, Toru; Asai, Keita; Yamori, Masashi; Teramukai, Satoshi; Bessho, Kazuhisa; Yokode, Masayuki; Fukushima, Masanori

2012-01-01

Objective The use of electronic medical record (EMR) data is necessary to improve clinical research efficiency. However, it is not easy to identify patients who meet research eligibility criteria and collect the necessary information from EMRs because the data collection process must integrate various techniques, including the development of a data warehouse and translation of eligibility criteria into computable criteria. This research aimed to demonstrate an electronic medical records retrieval system (ERS) and an example of a hospital-based cohort study that identified both patients and exposure with an ERS. We also evaluated the feasibility and usefulness of the method. Design The system was developed and evaluated. Participants In total, 800 000 cases of clinical information stored in EMRs at our hospital were used. Primary and secondary outcome measures The feasibility and usefulness of the ERS, the method to convert text from eligible criteria to computable criteria, and a confirmation method to increase research data accuracy. Results To comprehensively and efficiently collect information from patients participating in clinical research, we developed an ERS. To create the ERS database, we designed a multidimensional data model optimised for patient identification. We also devised practical methods to translate narrative eligibility criteria into computable parameters. We applied the system to an actual hospital-based cohort study performed at our hospital and converted the test results into computable criteria. Based on this information, we identified eligible patients and extracted data necessary for confirmation by our investigators and for statistical analyses with our ERS. Conclusions We propose a pragmatic methodology to identify patients from EMRs who meet clinical research eligibility criteria. Our ERS allowed for the efficient collection of information on the eligibility of a given patient, reduced the labour required from the investigators and improved the reliability of the results. PMID:23117567

Risk factors associated with endometriosis: importance of study population for characterizing disease in the ENDO Study

PubMed Central

Peterson, C. Matthew; Johnstone, Erica B.; Hammoud, Ahmad O.; Stanford, Joseph B.; Varner, Michael W.; Kennedy, Anne; Chen, Zhen; Sun, Liping; Fujimoto, Victor Y.; Hediger, Mary L.; Buck Louis, Germaine M.

2014-01-01

OBJECTIVE We sought to identify risk factors for endometriosis and their consistency across study populations in the Endometriosis: Natural History, Diagnosis, and Outcomes (ENDO) Study. STUDY DESIGN In this prospective matched, exposure cohort design, 495 women aged 18–44 years undergoing pelvic surgery (exposed to surgery, operative cohort) were compared to an age- and residence-matched population cohort of 131 women (unexposed to surgery, populationcohort). Endometriosis was diagnosed visually at laparoscopy/laparotomy or by pelvic magnetic resonance imaging in the operative and population cohorts, respectively. Logistic regression estimated the adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for each cohort. RESULTS The incidence of visualized endometriosis was 40% in the operative cohort (11.8% stage 3–4 by revised criteria from the American Society for Reproductive Medicine), and 11% stage 3–4 in the population cohort by magnetic resonance imaging. An infertility history increased the odds of an endometriosis diagnosis in both the operative (AOR, 2.43; 95% CI, 1.57–3.76) and population (AOR, 7.91; 95% CI, 1.69–37.2) cohorts. In the operative cohort only, dysmenorrhea (AOR, 2.46; 95% CI, 1.28–4.72) and pelvic pain (AOR, 3.67; 95% CI, 2.44–5.50) increased the odds of diagnosis, while gravidity (AOR, 0.49; 95% CI, 0.32–0.75), parity (AOR, 0.42; 95% CI, 0.28–0.64), and body mass index (AOR, 0.95; 95% CI, 0.93–0.98) decreased the odds of diagnosis. In all sensitivity analyses for different diagnostic subgroups, infertility history remained a strong risk factor. CONCLUSION An infertility history was a consistent risk factor for endometriosis in both the operative and population cohorts of the ENDO Study. Additionally, identified risk factors for endometriosis vary based upon cohort selection and diagnostic accuracy. Finally, endometriosis in the population may be more common than recognized. PMID:23454253

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

Subjective Grading of Subclinical Vitreous Floaters

PubMed Central

Tassignon, Marie-José; Ní Dhubhghaill, Sorcha; Ruiz Hidalgo, Irene; Rozema, Jos J.

2016-01-01

Purpose This study aimed to objectively grade the perception of subclinical floaters in an asymptomatic cohort. Design A prospective observational cohort study. Methods One hundred eighty-two volunteers (49 men, 133 women) with ages ranging from 17.7 to 78.6 years were recruited for floater assessment. Participants were assessed by a light box and by vitreoscope, after which they graded the floaters using a graphic classification system. They also completed a questionnaire to estimate the impact of floaters on daily life. In addition, biometric and refractive data were documented for all participants. Results Using the light box method, 67.6% of participants reported seeing transparent floaters, which increased to 84.1% when using the vitreoscope. Opaque floaters were seen by 15.9% (light box) and 6.5% (vitreoscope). Reported levels of floater discomfort varied between participants, with 80.2% of participants reporting no discomfort and 6.6% reporting moderate to manifest discomfort. The perceived discomfort was weakly correlated with the amount of visualized floaters (light box: Pearson r = 0.323, P < 0.001; vitreoscope: r = 0.174, P < 0.001). Both floater perception and discomfort increased with age (r = 0.203, P = 0.006; r = 0.194, P = 0.009, respectively), although neither changed with axial length or refraction (P = 0.131, P = 0.070, respectively). Conclusions The light box and the vitreoscope demonstrate that subclinical floaters are very common, even in nonsymptomatic subjects. The amount of perceived floaters in this cohort correlates only weakly with floater-related discomfort. PMID:26918903

Development of an In-House Multiplex Nested RT-PCR Method for Detecting Acute HIV-1 Infection in High Risk Populations.

PubMed

Liu, Zhiying; Li, Wei; Xu, Meng; Sheng, Bo; Yang, Zixuan; Jiao, Yanmei; Zhang, Tong; Mou, Danlei; Chen, Dexi; Wu, Hao

2015-01-01

The detection of acute HIV infection (AHI) among high risk populations can help reduce secondary transmission of HIV. The nucleic acid testing (NAT) can shorten the test window period by up to 7-12 days. In this study, we describe an in-house NAT based on the multiplex nested RT-PCR method to detect the HIV RNA. We also evaluated it in a high risk cohort in Beijing. Four primer pairs were designed and evaluated for the detection of different HIV-1 subtypes in group M. Multiplex RT-PCR and nested PCR were performed. The sensitivity, specialty, primers compatibility among HIV subtypes were evaluated simultaneously. In an MSM cohort in Beijing during a 3-year period, a total of 11,808 blood samples that were negative by ELISA or indeterminate by Western blot were analyzed by this multiplex nested RT-PCR with pooling strategy. The multiplex nested RT-PCR was successfully applied for the detection of at least six HIV-1 subtypes. The sensitivity was 40 copies/ml and the specificity was 100%. A total of 29 people were tested HIV-1 positive with acute infection in a MSM cohort of Beijing during a 3 years period. This multiplex nested RT-PCR provides a useful tool for the rapid detection of acute HIV-1 infection. When used in combination with the 3(rd) generation ELISA, it can improve the detection rate of HIV infection, especially in the source limited regions.

The Perils of Ignoring Design Effects in Experimental Studies: Lessons from a Mammography Screening Trial

PubMed Central

Glenn, Beth A.; Bastani, Roshan; Maxwell, Annette E.

2013-01-01

Objective Threats to external validity including pretest sensitization and the interaction of selection and an intervention are frequently overlooked by researchers despite their potential to significantly influence study outcomes. The purpose of this investigation was to conduct secondary data analyses to assess the presence of external validity threats in the setting of a randomized trial designed to promote mammography use in a high risk sample of women. Design During the trial, recruitment and intervention implementation took place in three cohorts (with different ethnic composition), utilizing two different designs (pretest-posttest control group design; posttest only control group design). Results Results reveal that the intervention produced different outcomes across cohorts, dependent upon the research design used and the characteristics of the sample. Conclusion These results illustrate the importance of weighing the pros and cons of potential research designs before making a selection and attending more closely to issues of external validity. PMID:23289517

The Self-Sufficiency Project at 36 Months: Effects on Children of a Program That Increased Parental Employment and Income.

ERIC Educational Resources Information Center

Morris, Pamela; Michalopoulos, Charles

This report examines effects of the Self-Sufficiency Project (SSP) for three age groups of children (younger cohort aged 3-5, middle cohort aged 6-11, and older cohort aged 12-18) at the 36-month interview. A companion report on effects of the SSP on adults is available separately. Chapter 1 describes the SSP incentive, project design, and SSP…

MODUL-a multicenter randomized clinical trial of biomarker-driven maintenance therapy following first-line standard induction treatment of metastatic colorectal cancer: an adaptable signal-seeking approach.

PubMed

Schmoll, Hans-Joachim; Arnold, Dirk; de Gramont, Aimery; Ducreux, Michel; Grothey, Axel; O'Dwyer, Peter J; Van Cutsem, Eric; Hermann, Frank; Bosanac, Ivan; Bendahmane, Belguendouz; Mancao, Christoph; Tabernero, Josep

2018-06-01

The old approach of one therapeutic for all patients with mCRC is evolving with a need to target specific molecular aberrations or cell-signalling pathways. Molecular screening approaches and new biomarkers are required to fully characterize tumours, identify patients most likely to benefit, and predict treatment response. MODUL is a signal-seeking trial with a design that is highly adaptable, permitting modification of different treatment cohorts and inclusion of further additional cohorts based on novel evidence on new compounds/combinations that emerge during the study. MODUL is ongoing and its adaptable nature permits timely and efficient recruitment of patients into the most appropriate cohort. Recruitment will take place over approximately 5 years in Europe, Asia, Africa, and South America. The design of MODUL with ongoing parallel/sequential treatment cohorts means that the overall size and duration of the trial can be modified/prolonged based on accumulation of new data. The early success of the current trial suggests that the design may provide definitive leads in a patient-friendly and relatively economical trial structure. Along with other biomarker-driven trials that are currently underway, it is hoped that MODUL will contribute to the continuing evolution of clinical trial design and permit a more 'tailored' approach to the treatment of patients with mCRC.

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…

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

Across-cohort QC analyses of GWAS summary statistics from complex traits.

PubMed

Chen, Guo-Bo; Lee, Sang Hong; Robinson, Matthew R; Trzaskowski, Maciej; Zhu, Zhi-Xiang; Winkler, Thomas W; Day, Felix R; Croteau-Chonka, Damien C; Wood, Andrew R; Locke, Adam E; Kutalik, Zoltán; Loos, Ruth J F; Frayling, Timothy M; Hirschhorn, Joel N; Yang, Jian; Wray, Naomi R; Visscher, Peter M

2016-01-01

Genome-wide association studies (GWASs) have been successful in discovering SNP trait associations for many quantitative traits and common diseases. Typically, the effect sizes of SNP alleles are very small and this requires large genome-wide association meta-analyses (GWAMAs) to maximize statistical power. A trend towards ever-larger GWAMA is likely to continue, yet dealing with summary statistics from hundreds of cohorts increases logistical and quality control problems, including unknown sample overlap, and these can lead to both false positive and false negative findings. In this study, we propose four metrics and visualization tools for GWAMA, using summary statistics from cohort-level GWASs. We propose methods to examine the concordance between demographic information, and summary statistics and methods to investigate sample overlap. (I) We use the population genetics F st statistic to verify the genetic origin of each cohort and their geographic location, and demonstrate using GWAMA data from the GIANT Consortium that geographic locations of cohorts can be recovered and outlier cohorts can be detected. (II) We conduct principal component analysis based on reported allele frequencies, and are able to recover the ancestral information for each cohort. (III) We propose a new statistic that uses the reported allelic effect sizes and their standard errors to identify significant sample overlap or heterogeneity between pairs of cohorts. (IV) To quantify unknown sample overlap across all pairs of cohorts, we propose a method that uses randomly generated genetic predictors that does not require the sharing of individual-level genotype data and does not breach individual privacy.

Across-cohort QC analyses of GWAS summary statistics from complex traits

PubMed Central

Chen, Guo-Bo; Lee, Sang Hong; Robinson, Matthew R; Trzaskowski, Maciej; Zhu, Zhi-Xiang; Winkler, Thomas W; Day, Felix R; Croteau-Chonka, Damien C; Wood, Andrew R; Locke, Adam E; Kutalik, Zoltán; Loos, Ruth J F; Frayling, Timothy M; Hirschhorn, Joel N; Yang, Jian; Wray, Naomi R; Visscher, Peter M

2017-01-01

Genome-wide association studies (GWASs) have been successful in discovering SNP trait associations for many quantitative traits and common diseases. Typically, the effect sizes of SNP alleles are very small and this requires large genome-wide association meta-analyses (GWAMAs) to maximize statistical power. A trend towards ever-larger GWAMA is likely to continue, yet dealing with summary statistics from hundreds of cohorts increases logistical and quality control problems, including unknown sample overlap, and these can lead to both false positive and false negative findings. In this study, we propose four metrics and visualization tools for GWAMA, using summary statistics from cohort-level GWASs. We propose methods to examine the concordance between demographic information, and summary statistics and methods to investigate sample overlap. (I) We use the population genetics Fst statistic to verify the genetic origin of each cohort and their geographic location, and demonstrate using GWAMA data from the GIANT Consortium that geographic locations of cohorts can be recovered and outlier cohorts can be detected. (II) We conduct principal component analysis based on reported allele frequencies, and are able to recover the ancestral information for each cohort. (III) We propose a new statistic that uses the reported allelic effect sizes and their standard errors to identify significant sample overlap or heterogeneity between pairs of cohorts. (IV) To quantify unknown sample overlap across all pairs of cohorts, we propose a method that uses randomly generated genetic predictors that does not require the sharing of individual-level genotype data and does not breach individual privacy. PMID:27552965

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.

Exposure enriched outcome dependent designs for longitudinal studies of gene-environment interaction.

PubMed

Sun, Zhichao; Mukherjee, Bhramar; Estes, Jason P; Vokonas, Pantel S; Park, Sung Kyun

2017-08-15

Joint effects of genetic and environmental factors have been increasingly recognized in the development of many complex human diseases. Despite the popularity of case-control and case-only designs, longitudinal cohort studies that can capture time-varying outcome and exposure information have long been recommended for gene-environment (G × E) interactions. To date, literature on sampling designs for longitudinal studies of G × E interaction is quite limited. We therefore consider designs that can prioritize a subsample of the existing cohort for retrospective genotyping on the basis of currently available outcome, exposure, and covariate data. In this work, we propose stratified sampling based on summaries of individual exposures and outcome trajectories and develop a full conditional likelihood approach for estimation that adjusts for the biased sample. We compare the performance of our proposed design and analysis with combinations of different sampling designs and estimation approaches via simulation. We observe that the full conditional likelihood provides improved estimates for the G × E interaction and joint exposure effects over uncorrected complete-case analysis, and the exposure enriched outcome trajectory dependent design outperforms other designs in terms of estimation efficiency and power for detection of the G × E interaction. We also illustrate our design and analysis using data from the Normative Aging Study, an ongoing longitudinal cohort study initiated by the Veterans Administration in 1963. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Impact of Just-in-Time and Just-in-Place Simulation on Intern Success With Infant Lumbar Puncture.

PubMed

Kessler, David; Pusic, Martin; Chang, Todd P; Fein, Daniel M; Grossman, Devin; Mehta, Renuka; White, Marjorie; Jang, Jaewon; Whitfill, Travis; Auerbach, Marc

2015-05-01

Simulation-based skill trainings are common; however, optimal instructional designs that improve outcomes are not well specified. We explored the impact of just-in-time and just-in-place training (JIPT) on interns' infant lumbar puncture (LP) success. This prospective study enrolled pediatric and emergency medicine interns from 2009 to 2012 at 34 centers. Two distinct instructional design strategies were compared. Cohort A (2009-2010) completed simulation-based training at commencement of internship, receiving individually coached practice on the LP simulator until achieving a predefined mastery performance standard. Cohort B (2010-2012) had the same training plus JIPT sessions immediately before their first clinical LP. Main outcome was LP success, defined as obtaining fluid with first needle insertion and <1000 red blood cells per high-power field. Process measures included use of analgesia, early stylet removal, and overall attempts. A total of 436 first infant LPs were analyzed. The LP success rate in cohort A was 35% (13/37), compared with 38% (152/399) in cohort B (95% confidence interval for difference [CI diff], -15% to +18%). Cohort B exhibited greater analgesia use (68% vs 19%; 95% CI diff, 33% to 59%), early stylet removal (69% vs 54%; 95% CI diff, 0% to 32%), and lower mean number of attempts (1.4 ± 0.6 vs 2.1 ± 1.6, P < .01) compared with cohort A. Across multiple institutions, intern success rates with infant LP are poor. Despite improving process measures, adding JIPT to training bundles did not improve success rate. More research is needed on optimal instructional design strategies for infant LP. Copyright © 2015 by the American Academy of Pediatrics.

The perils of ignoring design effects in experimental studies: lessons from a mammography screening trial.

PubMed

Glenn, Beth A; Bastani, Roshan; Maxwell, Annette E

2013-01-01

Threats to external validity, including pretest sensitisation and the interaction of selection and an intervention, are frequently overlooked by researchers despite their potential to significantly influence study outcomes. The purpose of this investigation was to conduct secondary data analyses to assess the presence of external validity threats in the setting of a randomised trial designed to promote mammography use in a high-risk sample of women. During the trial, recruitment and intervention, implementation took place in three cohorts (with different ethnic composition), utilising two different designs (pretest-posttest control group design and posttest only control group design). Results reveal that the intervention produced different outcomes across cohorts, dependent upon the research design used and the characteristics of the sample. These results illustrate the importance of weighing the pros and cons of potential research designs before making a selection and attending more closely to issues of external validity.

Foodborne gastroenteritis outbreak in an Austrian healthcare facility caused by asymptomatic, norovirus-excreting kitchen staff.

PubMed

Schmid, D; Kuo, H-W; Hell, M; Kasper, S; Lederer, I; Mikula, C; Springer, B; Allerberger, F

2011-03-01

An outbreak of norovirus GGII.4 2006b affected an Austrian 600-bed healthcare facility from 15 to 27 March 2009. A total of 204 patients, residents and staff fitted the outbreak case definition; 17 (8.3%) were laboratory-confirmed. Foodborne origin was suspected in the 114 patient and resident cases with onset 15-18 March. A case-cohort study was performed to test the hypothesis that consumption of dishes offered on 14, 15 and 16 March (risk days) was associated with increased risk of infection. Data on food exposure of 62% (317/510) of the patient and resident cohort were available for a simultaneous retrospective cohort study. The case-cohort analysis revealed that consumption of sliced cold sausage offered on 15 March [odds ratio (OR): 3.98; 95% confidence interval (CI): 1.18-14.1], a meat dish with salad (adjusted OR: 2.2; 95% CI: 1.19-4.08) and a rolled spinach pancake (adjusted OR: 2.17; 95% CI: 1.27-3.71) on 16 March were independent risk factors. It is likely that one of the five asymptomatic excretors among the kitchen staff on duty on the risk days was the source of food contamination. The case-cohort study design was found to be a valid alternative to the retrospective cohort study design for the investigation of a suspected foodborne outbreak in a large cohort. Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

Differentiation of Period, Age, and Cohort Effects on Drug Use 1976-1986. Monitoring the Future Occasional Paper Series, Paper 22.

ERIC Educational Resources Information Center

O'Malley, Patrick M.; And Others

Conducted as part of the Monitoring the Future project, this study used a cohort-sequential design to examine period, age, and cohort effects on substance use among American youth between the ages of 18 and 28 from the high school classes of 1976 to 1986. This manuscript supersedes Paper 14 in the series which reported on American youth from 18-24…

Analyzing change in short-term longitudinal research using cohort-sequential designs.

PubMed

Anderson, E R

1993-12-01

This article illustrates a method for approximating longitudinal data analysis by combining information from different overlapping age groups to form a single developmental growth curve. Using this method, hypotheses about the form of growth, the extent of individual differences in growth, and factors that affect the rate and pattern of growth are investigated. The example used to illustrate this method examines the growth of externalizing behavior and of negativity in parent-child relationships during early adolescence using assessments from multiple methods and multiple informants. These 3 dimensions changed significantly during this period, with parental negativity increasing more rapidly after age 12. However, there were substantial individual differences in the pattern of change in these dimensions. Gender of child and type of family situation (nondivorced, divorced, and remarried) were investigated as possible factors affecting change.

REGRESSION MODELS FOR COHORT MORTALITY STUDIES

EPA Science Inventory

Cohort studies evaluate suspect health hazards from occupational or environmental exposures by recording tile facts and causes of deaths in the exposed group as they occur over an extended time period. his article reviews several methods for analyzing cohort: mortality data and s...

Methodology of the Pelotas birth cohort study from 1982 to 2004-5, Southern Brazil

PubMed Central

Barros, Fernando C; Victora, Cesar G; Horta, Bernardo L; Gigante, Denise P

2009-01-01

OBJECTIVE: To describe the methods employed in the longitudinal and follow-up studies of children born in Pelotas (Southern Brazil) in 1982. METHODS: The cohort began with a perinatal health survey that included all 6,011 children born in maternity wards in Pelotas in 1982. The 5,914 children born alive in the city were included in the follow-up studies. By 2004-5, we had conducted eight follow-ups, which consisted of the administration of questionnaires to mothers and/or cohort members, depending on age, in addition to anthropometric and clinical examination. Cohort subjects are described in terms of demographic, socioeconomic, and health-related variables collected during early follow-up studies, which are used as exposure variables. RESULTS: The majority of subjects in the cohort were followed for 23 years and on multiple occasions. The most successful follow-ups were those preceded by a city census. Using this method, we were able to locate 87.2% of subjects in 1984 (mean age 19 months), 84.1% in 1986 (mean age 43 months), and 77.4% in 2004-5, and 77.4% in 2004-5 (mean age 23 years). CONCLUSIONS: Birth cohort studies can be carried out successfully in developing countries, and the methods employed in this life-cycle study have allowed us to investigate the influence of early exposures in determining disease outcomes in adult life. PMID:19142340

DEMONSTRATION OF LOW COST, LOW BURDEN EXPOSURE MONITORING STRATEGIES FOR USE IN LONGITUDINAL COHORT STUDIES

EPA Science Inventory

A large longitudinal cohort study designed to evaluate the association between children's exposures to environmental agents and health outcomes presents many challenges for exposure monitoring. Exposure of the child must be measured for multiple chemicals through multiple path...

Integrated methods for teaching population health.

PubMed

Sistrom, Maria Gilson; Zeigen, Laura; Jones, Melissa; Durham, Korana Fiol; Boudrot, Thomas

2011-01-01

The Institute of Medicine recommends reforms to public health education to better prepare the public health workforce. This study addresses the application of two of the recommended reforms in the population health nursing curriculum at one university: use of an ecological model and distance learning methods. Using interdisciplinary faculty, integrated teaching and learning methods, and a multimedia curriculum, this study examined the following question: can distance learning be designed to support learning goals and outcomes specific to an ecological approach and population health concepts in general? Course content was evaluated using students' perception of practice utility and understanding of population health concepts. Integrated teaching methods were evaluated using a scale as well as comparison to other student distance learning experiences within the university. Findings demonstrated that both the ecological model and distance learning methods were successfully used to teach population health to a large nursing student cohort. 2011, SLACK Incorporated.

The Robert Wood Johnson Foundation Nurse Faculty Scholars Program: An opportunity for junior nurse faculty

PubMed Central

Coffman, Maren J.; Goodman, Janice H.; Thomas, Tami L.; Roberson, Donna

2014-01-01

The Robert Wood Johnson Foundation Nurse Faculty Scholars program provides promising junior faculty extramural funding, expert mentoring, and the training needed to be successful in the academic role. The Nurse Faculty Scholars program, which admitted its first cohort in 2008, is designed to address the nursing faculty shortage by enhancing leadership, educational, and research skills in junior nursing faculty. This article provides an overview of the program, its purpose, and its eligibility requirements. The authors give strategies for selecting mentors, developing the written application, and preparing for an oral interview. Finally, the authors provide an analysis of funded institutions, research design and methods from current and recently funded projects, and rank and positions held by nursing mentors. PMID:22818282

Treatment of pregnancy-related pelvic girdle and/or low back pain after delivery design of a randomized clinical trial within a comprehensive prognostic cohort study [ISRCTN08477490

PubMed Central

Bastiaenen, Caroline HG; de Bie, Rob A; Wolters, Pieter MJC; Vlaeyen, Johan WS; Bastiaanssen, Janneke M; Klabbers, Aldegonda BA; Heuts, Annie; van den Brandt, Piet A; Essed, Gerard GM

2004-01-01

Background Pregnancy-related pelvic girdle and/or low back pain is a controversial syndrome because insight in etiology and prognosis is lacking. The controversy relates to factors eliciting pain and some prognostic factors such as the interpretation of pain at the symphysis. Recent research about treatment strategies also reflects those various opinions, in fact suggesting there is professional uncertainty about the optimal approach. Currently, physiotherapists often prescribe a pain-contingent treatment regime of relative rest and avoiding several day-to-day activities. Additionally, treatment more often includes an exercise program to guide rectification of the muscle imbalance and alignment of the pelvic girdle. Effectiveness of those interventions is not proven and the majority of the studies are methodologically flawed. Investigators draw particular attention to biomedical factors but there is growing evidence that important prognostic issues such as biopsychosocial factors appear to be even more important as point of action in a treatment program. Methods/design This pragmatic randomized controlled trial is designed to evaluate the effectiveness of a tailor-made treatment program with respect to biopsychosocial factors in primary care. The effect of the experimental intervention and usual care are evaluated as they are applied in primary health care. The trial is embedded in a cohort study that is designed as a longitudinal, prospective study, which studies prevalence, etiology, severity and prognosis during pregnancy until one year after delivery. The present paper focuses on choices regarding recruitment procedures, in-/exclusion criteria and the development of a well-timed intervention. Discussion This section briefly discusses the actions taken to minimize bias in the design, the proper time-window for the experimental intervention and the contrast between the experimental intervention and usual care. PMID:15619331

Individual Patterns of Enrolment in Primary Schools in the Republic of Honduras

ERIC Educational Resources Information Center

Sekiya, Takeshi

2014-01-01

The Reconstructed Cohort Method is often used to examine the status of national education. However, this method does not account for individual details and we know little about the status of school enrolments by tracking individual students from entrance until dropout or graduation. This study employs the True Cohort Method to analyse data for…

Design and Phenomenology of the FEBSTAT Study

PubMed Central

Hesdorffer, Dale C; Shinnar, Shlomo; Lewis, Darrell V; Moshé, Solomon L; Nordli, Douglas R; Pellock, John M; MacFall, James; Shinnar, Ruth C; Masur, David; Frank, L Matthew; Epstein, Leon G; Litherland, Claire; Seinfeld, Syndi; Bello, Jacqueline A; Chan, Stephen; Bagiella, Emilia; Sun, Shumei

2012-01-01

Purpose Febrile status epilepticus (FSE) has been associated with hippocampal injury and subsequent hipppocampal sclerosis (HS) and temporal lobe epilepsy. The FEBSTAT study was designed to prospectively examine the association between prolonged febrile seizures and development of HS and associated temporal lobe epilepsy, one of the most controversial issues in epilepsy. We report on the baseline phenomenology of the final cohorts as well as detailed aims and methodology. Methods The “Consequences of Prolonged Febrile Seizures in Childhood” (FEBSTAT) study is a prospective, multicenter study. Enrolled are children, aged 1 month to 6 years, presenting with a febrile seizure lasting 30 minutes or more based upon ambulance, emergency department, and hospital records, and parental interview. At baseline, procedures included an MRI and EEG done within 72 hours of FSE, and a detailed history and neurological examination. Baseline development and behavior are assessed at one month. The baseline assessment is repeated, with age- appropriate developmental testing at one and five years after enrollment as well as at the development of epilepsy and one year after that. Telephone calls every three months document further seizures. Two other groups of children are included: a ‘control’ group consisting of children with a first febrile seizure ascertained at Columbia University and with almost identical baseline and one year follow-up examinations and a pilot cohort of FSE from Duke University. Key findings The FEBSTAT cohort consists of 199 children with a median age at baseline of 16.0 months (Interquartile range (IQR)=12.0–24.0) and a median duration of FSE of 70.0 minutes (IQR=47.0–110.0). Seizures were continuous in 57.3% and behaviorally intermittent (without recovery in between) in 31.2%; most were partial (4;2.0%) or secondary generalized (65.8%), and almost all (98.0%) culminated in a generalized tonic clonic seizure. Of the 199 children, 86.4% had normal development and 20% had prior febrile seizures. In one third of cases, FSE was unrecognized in the emergency department. The Duke existing cohort consists of 23 children with a median age of FSE onset of 18.0 months (IQR 14.0–28.0) and median duration of FSE of 90.0 minutes (IQR 50.0–170.0). The Columbia control cohort consists of 159 children with a first febrile seizure who received almost the same work-up as the FEBSTAT cohort at baseline and at one-year. They were followed by telephone every 4 months for a median of 42 months. Among the control cohort, 64.2% had a first simple FS, 26.4% had a first complex FS that was not FSE, and 9.4% had FSE. Among the 15 with FSE, the median age at onset was 14.0 months (IQR 12.0–20.0) and the median duration of FSE was 43.0 minutes (IQR 35.0–75.0). Significance The FEBSTAT study presents an opportunity to prospectively study the relationship between FSE and acute hippocampal damage, the development of MTS, epilepsy (particularly TLE), and impaired hippocampal function in a large cohort. It is hoped that this study may illuminate a major mystery in clinical epilepsy today, and permit the development of interventions designed to prevent the sequelae of FSE. PMID:22742587

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

Radial Neck Dilatory Remodeling After Radial Head Arthroplasty With an Uncemented, Press Fit, Fully Chemically Etched Stem Design.

PubMed

Sullivan, Matthew P; Firoozabadi, Reza; Kennedy, Stephen A; Agel, Julie; Magnusson, Eric; Schiffman, Brett; Folchert, Matthew; Beingessner, Daphne

2017-09-01

To compare the radiographic outcomes of 2 widely used side loading, press fit, RHA implants used to reconstruct complex elbow trauma. Retrospective cohort study. Level-1 Academic trauma center. Patients undergoing RHA. Cohort 1 received Synthes Radial Head Prosthesis. Cohort 2 received Biomet ExploR Radial Head Replacement. Radial neck dilatory remodeling. Eighty-two subjects were included in final analysis, 63 from the Biomet Cohort, and 19 from Synthes cohort. Demographic and injury characteristics were similar among cohorts. Radial neck dilatory remodeling as well as periprosthetic radiographic lucency were seen significantly more frequently and to a significantly greater degree in the Synthes cohort. The average percentage of dilatory remodeling of the Synthes cohort was 34.9% and that of the Biomet cohort was 2.7%. There were no differences in rates of revision surgery. Our study demonstrates significant radiographic differences between 2 frequently used RHA implants. Radial neck dilatory remodeling is a common, rapidly progressive, and dramatic finding frequently seen with the Synthes Radial Head Prosthesis. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The First Six Years of Building and Implementing a Return-to-Work Service for Patients with Acquired Brain Injury. The Rapid-Return-to-Work-Cohort-Study.

PubMed

Haveraaen, L; Brouwers, E P M; Sveen, U; Skarpaas, L S; Sagvaag, H; Aas, R W

2017-12-01

Background and objective Despite large activity worldwide in building and implementing new return-to-work (RTW) services, few studies have focused on how such implementation processes develop. The aim of this study was to examine the development in patient and service characteristics the first six years of implementing a RTW service for persons with acquired brain injury (ABI). Methods The study was designed as a cohort study (n=189). Data were collected by questionnaires, filled out by the service providers. The material was divided into, and analyzed with, two implementation phases. Non-parametrical statistical methods and hierarchical regression analyses were applied on the material. Results The number of patients increased significantly, and the patient group became more homogeneous. Both the duration of the service, and the number of consultations and group session days were significantly reduced. Conclusion The patient group became more homogenous, but also significantly larger during the first six years of building the RTW service. At the same time, the duration of the service decreased. This study therefore questions if there is a lack of consensus on the intensity of work rehabilitation for this group.

Analysis of Sequence Data Under Multivariate Trait-Dependent Sampling.

PubMed

Tao, Ran; Zeng, Donglin; Franceschini, Nora; North, Kari E; Boerwinkle, Eric; Lin, Dan-Yu

2015-06-01

High-throughput DNA sequencing allows for the genotyping of common and rare variants for genetic association studies. At the present time and for the foreseeable future, it is not economically feasible to sequence all individuals in a large cohort. A cost-effective strategy is to sequence those individuals with extreme values of a quantitative trait. We consider the design under which the sampling depends on multiple quantitative traits. Under such trait-dependent sampling, standard linear regression analysis can result in bias of parameter estimation, inflation of type I error, and loss of power. We construct a likelihood function that properly reflects the sampling mechanism and utilizes all available data. We implement a computationally efficient EM algorithm and establish the theoretical properties of the resulting maximum likelihood estimators. Our methods can be used to perform separate inference on each trait or simultaneous inference on multiple traits. We pay special attention to gene-level association tests for rare variants. We demonstrate the superiority of the proposed methods over standard linear regression through extensive simulation studies. We provide applications to the Cohorts for Heart and Aging Research in Genomic Epidemiology Targeted Sequencing Study and the National Heart, Lung, and Blood Institute Exome Sequencing Project.

Does stent strut design impact clinical outcomes: comparative safety and efficacy of Endeavor Resolute versus Resolute Integrity zotarolimus-eluting stents.

PubMed

Di Santo, Pietro; Simard, Trevor; Ramirez, F Daniel; Pourdjabbar, Ali; Harnett, David T; Singh, Kuljit; Moreland, Robert; Chong, Aun-Yeong; Dick, Alexander; Labinaz, Marino; Froeschl, Michael; Froeschl, Michael; Le May, Michael R; So, Derek Y; Hibbert, Benjamin

2015-10-07

Percutaneous coronary intervention is the most commonly performed method of revascularizing obstructive coronary artery disease. The impact of stent strut design on clinical outcomes remains unclear. The Endeavour Resolute (ER-ZES) and the Resolute Integrity (RI-ZES) zotarolimus-eluting stents utilize identical polymers and anti-proliferative agents, differing only in their respective strut design. This study assessed the comparative safety and efficacy of these two stents in unrestricted contemporary real-world practice. A total of 542 patients were identified, corresponding to 340 ER-ZES and 480 RI-ZES. The primary endpoint was major adverse cardiac events (MACE) defined by a composite of death, nonfatal myocardial infarction and stroke. Secondary endpoints included post-procedural length of stay, in-stent restenosis, target lesion revascularization, target vessel revascularization, coronary artery bypass grafting and stent thrombosis. MACE occurred in 3.2% of the ER-ZES cohort and 5.0% of the RI-ZES cohort (p= 0.43). Adjusted analysis utilizing propensity score-adjusted odds ratio for MACE, was 1.37 (95% CI 0.46-4.07, p=0.57). The mortality rate (0.9% ER-ZES vs. 1.9% RI-ZES, p=0.59), non-fatal MI (2.3% ER-ZES vs. 3.1% RI-ZES, p=0.75) and stroke (0.0% ER-ZES vs. 0.3% RI-ZES, p=0.85) were not different. Additionally, there was no difference in any of secondary outcomes. The clinical performance and safety of both ER-ZES and RI-ZES were not statistically different, despite differences in stent strut design.

TEAM-HF Cost-Effectiveness Model: A Web-Based Program Designed to Evaluate the Cost-Effectiveness of Disease Management Programs in Heart Failure

PubMed Central

Reed, Shelby D.; Neilson, Matthew P.; Gardner, Matthew; Li, Yanhong; Briggs, Andrew H.; Polsky, Daniel E.; Graham, Felicia L.; Bowers, Margaret T.; Paul, Sara C.; Granger, Bradi B.; Schulman, Kevin A.; Whellan, David J.; Riegel, Barbara; Levy, Wayne C.

2015-01-01

Background Heart failure disease management programs can influence medical resource use and quality-adjusted survival. Because projecting long-term costs and survival is challenging, a consistent and valid approach to extrapolating short-term outcomes would be valuable. Methods We developed the Tools for Economic Analysis of Patient Management Interventions in Heart Failure (TEAM-HF) Cost-Effectiveness Model, a Web-based simulation tool designed to integrate data on demographic, clinical, and laboratory characteristics, use of evidence-based medications, and costs to generate predicted outcomes. Survival projections are based on a modified Seattle Heart Failure Model (SHFM). Projections of resource use and quality of life are modeled using relationships with time-varying SHFM scores. The model can be used to evaluate parallel-group and single-cohort designs and hypothetical programs. Simulations consist of 10,000 pairs of virtual cohorts used to generate estimates of resource use, costs, survival, and incremental cost-effectiveness ratios from user inputs. Results The model demonstrated acceptable internal and external validity in replicating resource use, costs, and survival estimates from 3 clinical trials. Simulations to evaluate the cost-effectiveness of heart failure disease management programs across 3 scenarios demonstrate how the model can be used to design a program in which short-term improvements in functioning and use of evidence-based treatments are sufficient to demonstrate good long-term value to the health care system. Conclusion The TEAM-HF Cost-Effectiveness Model provides researchers and providers with a tool for conducting long-term cost-effectiveness analyses of disease management programs in heart failure. PMID:26542504

Design, implementation, and quality control in the Pathways American-Indian multicenter trial

PubMed Central

Stone, Elaine J.; Norman, James E.; Davis, Sally M.; Stewart, Dawn; Clay, Theresa E.; Caballero, Ben; Lohman, Timothy G.; Murray, David M.

2016-01-01

Background Pathways was the first multicenter American-Indian school-based study to test the effectiveness of an obesity prevention program promoting healthy eating and physical activity. Methods Pathways employed a nested cohort design in which 41 schools were randomized to intervention or control conditions and students within these schools were followed as a cohort (1,704 third graders at baseline). The study’s primary endpoint was percent body fat. Secondary endpoints were levels of fat in school lunches; time spent in physical activity; and knowledge, attitudes, and behaviors regarding diet and exercise. Quality control (QC) included design of data management systems which provided standardization and quality assurance of data collection and processing. Data QC procedures at study centers included manuals of operation, training and certification, and monitoring of performance. Process evaluation was conducted to monitor dose and fidelity of the interventions. Registration and tracking systems were used for students and schools. Results No difference in mean percent body fat at fifth grade was found between the intervention and control schools. Percent of calories from fat and saturated fat in school lunches was significantly reduced in the intervention schools as was total energy intake from 24-hour recalls. Significant increases in self-reported physical activity levels and knowledge of healthy behaviors were found for the intervention school students. Conclusions The Pathways study results provide evidence demonstrating the role schools can play in public health promotion. Its study design and QC systems and procedures provide useful models for other similar school based multi- or single-site studies. PMID:14636805

The Cohort for Childhood Origin of Asthma and allergic diseases (COCOA) study: design, rationale and methods

PubMed Central

2014-01-01

Background This paper describes the background, aim, and design of a prospective birth-cohort study in Korea called the COhort for Childhood Origin of Asthma and allergic diseases (COCOA). COCOA objectives are to investigate the individual and interactive effects of genetics, perinatal environment, maternal lifestyle, and psychosocial stress of mother and child on pediatric susceptibility to allergic diseases. Methods/Design The participants in COCOA represents a Korean inner-city population. Recruitment started on 19 November, 2007 and will continue until 31 December, 2015. Recruitment is performed at five medical centers and eight public-health centers for antenatal care located in Seoul. Participating mother-baby pairs are followed from before birth to adolescents. COCOA investigates whether the following five environmental variables contribute causally to the development and natural course of allergic diseases: (1) perinatal indoor factors (i.e. house-dust mite, bacterial endotoxin, tobacco smoking, and particulate matters 2.5 and 10), (2) perinatal outdoor pollutants, (3) maternal prenatal psychosocial stress and the child’s neurodevelopment, (4) perinatal nutrition, and (5) perinatal microbiome. Cord blood and blood samples from the child are used to assess whether the child’s genes and epigenetic changes influence allergic-disease susceptibility. Thus, COCOA aims to investigate the contributions of genetics, epigenetics, and various environmental factors in early life to allergic-disease susceptibility in later life. How these variables interact to shape allergic-disease susceptibility is also a key aim. The COCOA data collection schedule includes 11 routine standardized follow-up assessments of all children at 6 months and every year until 10 years of age, regardless of allergic-disease development. The mothers will complete multiple questionnaires to assess the baseline characteristics, the child’s exposure to environmental factors, maternal pre- and post-natal psychological stress, and the child’s neurodevelopment, nutritional status, and development of allergic and respiratory illnesses. The child’s microbiome, genes, epigenetics, plasma cytokine levels, and neuropsychological status, the microbiome of the residence, and the levels of indoor and outdoor pollutants are measured by standard procedures. Discussion The COCOA study will improve our understanding of how individual genetic or environmental risk factors influence susceptibility to allergic disease and how these variables interact to shape the phenotype of allergic diseases. PMID:24990471

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.

Long-Term Unemployment and Suicide: A Systematic Review and Meta-Analysis

PubMed Central

Milner, Allison; Page, Andrew; LaMontagne, Anthony D.

2013-01-01

Purpose There have been a number of reviews on the association+ between unemployment and suicide, but none have investigated how this relationship is influenced by duration of unemployment. Method A systematic review and meta-analysis was conducted of those studies that assessed duration of unemployment as a risk factor for suicide. Studies considered as eligible for inclusion were population-based cohort or case-control designs; population-based ecological designs, or hospital based clinical cohort or case-control designs published in the year 1980 or later. Results The review identified 16 eligible studies, out of a possible 10,358 articles resulting from a search of four databases: PubMed, Web of Knowledge, Scopus and Proquest. While all 16 studies measured unemployment duration in different ways, a common finding was that longer duration of unemployment was related to greater risk of suicide and suicide attempt. A random effects meta-analysis on a subsample of six cohort studies indicated that the pooled relative risk of suicide in relation to average follow-up time after unemployment was 1.70 (95% CI 1.22 to 2.18). However, results also suggested a possible habituation effect to unemployment over time, with the greatest risk of suicide occurring within five years of unemployment compared to the employed population (RR = 2.50, 95% CI 1.83 to 3.17). Relative risk appeared to decline in studies of those unemployed between 12 and 16 years compared to those currently employed (RR = 1.21, 95% CI 1.10 to 1.33). Conclusion Findings suggest that long-term unemployment is associated with greater incidence of suicide. Results of the meta-analysis suggest that risk is greatest in the first five years, and persists at a lower but elevated level up to 16 years after unemployment. These findings are limited by the paucity of data on this topic. PMID:23341881

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.

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

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.

Genetic vasopressin 1b receptor variance in overweight and diabetes mellitus

PubMed Central

Enhörning, Sofia; Sjögren, Marketa; Hedblad, Bo; Nilsson, Peter M; Struck, Joachim; Melander, Olle

2016-01-01

Objective Recently, imbalance in the vasopressin (AVP) system, measured as elevated levels of copeptin (the C-terminal part of the AVP pro-hormone) in plasma, was linked to the development of abdominal obesity and diabetes mellitus (DM). Here, we aim to investigate if the genetic variation of the human AVP receptor 1b gene (AVPR1B) is associated with measures of obesity and DM. Design Malmö Diet and Cancer study (MDC) is a population-based prospective cohort examined 1991–1996. Methods Four tag single nucleotide polymorphisms (SNPs: rs35810727, rs28373064, rs35439639, rs35608965) of AVPR1B were genotyped in the cardiovascular cohort (n=6103) of MDC (MDC-CC) and associated with measures of obesity and DM. Significant SNPs were replicated in another 24 344 MDC individuals (MDC replication cohort). Results In MDC-CC, the major allele of rs35810727 was associated with elevated BMI (β-coefficient±s.e.m.; 0.30±0.14, P=0.03) and waist (0.78±0.36, P=0.03) after age and gender adjustment. The association with BMI was replicated in the MDC replication cohort (0.21±0.07, P=0.003), whereas that with waist was not significant. In MDC-CC there was no association between the major allele of rs35810727 and DM, but in the complete MDC cohort (n=30 447) the major allele of rs35810727 was associated with DM (OR (95% CI); 1.10 (1.00–1.20), P=0.04). Conclusions Genetic variance of AVPR1B contributes to overweight. Furthermore, our data indicate a link between AVPR1B variance and DM development. Our data point at a relationship between the disturbance of the pharmacologically modifiable AVP system and the body weight regulation. PMID:26503846

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

Improving medication titration in heart failure by embedding a structured medication titration plan.

PubMed

Hickey, Annabel; Suna, Jessica; Marquart, Louise; Denaro, Charles; Javorsky, George; Munns, Andrew; Mudge, Alison; Atherton, John J

2016-12-01

To improve up-titration of medications to target dose in heart failure patients by improving communication from hospital to primary care. This quality improvement project was undertaken within three heart failure disease management (HFDM) services in Queensland, Australia. A structured medication plan was collaboratively designed and implemented in an iterative manner, using methods including awareness raising and education, audit and feedback, integration into existing work practice, and incentive payments. Evaluation was undertaken using sequential audits, and included process measures (use of the titration plan, assignment of responsibility) and outcome measures (proportion of patients achieving target dose) in HFDM service patients with reduced left ventricular ejection fraction. Comparison of the three patient cohorts (pre-intervention cohort A n=96, intervention cohort B n=95, intervention cohort C n=89) showed increase use of the titration plan, a shift to greater primary care responsibility for titration, and an increase in the proportion of patients achieving target doses of angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEI/ARB) (A 37% vs B 48% vs C 55%, p=0.051) and beta-blockers (A 38% vs B 33% vs C 51%, p=0.045). Combining all three cohorts, patients not on target doses when discharged from hospital were more likely to achieve target doses of ACEI/ARB (p<0.0001) and beta blockers (p<0.0001) within six months if they received a medication titration plan. A medication titration plan was successfully implemented in three HFDM services and improved transitional communication and achievement of target doses of evidence-based therapies within six months of hospital discharge. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A nationwide population-based retrospective cohort study of the risk of uterine, ovarian and breast cancer in women with polycystic ovary syndrome.

PubMed

Shen, Cheng-Che; Yang, Albert C; Hung, Jeng-Hsiu; Hu, Li-Yu; Tsai, Shih-Jen

2015-01-01

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women of reproductive age. We used a nationwide population-based retrospective cohort study to explore the relationship between PCOS and the subsequent development of gynecological cancers including uterine, breast, or ovarian cancer. We identified subjects who were diagnosed with PCOS between January 1, 2000, and December 31, 2004, in the Taiwan National Health Insurance (NHI) Research Database. A comparison cohort was constructed for patients without known PCOS who were also matched according to age. All PCOS and control patients were observed until diagnosed with breast cancer, ovarian cancer, or uterine cancer or until death, withdrawal from the NHI system, or December 31, 2009. The PCOS cohort consisted of 3,566 patients, and the comparison cohort consisted of 14,264 matched control patients without PCOS. The adjusted hazard ratio (HR) of uterine cancer and breast cancer in subjects with PCOS were higher (HR: 8.42 [95% confidence interval: 1.62-43.89] and HR: 1.99 [95% confidence interval: 1.05-3.77], respectively) than that of the controls during the follow-up. With the Monte Carlo method, only the mean adjusted HR of 1,000 comparisons for developing uterine cancer during the follow-up period was greater for the PCOS group than for the control groups (HR: 4.71, 95% confidence interval: 1.57-14.11). PCOS might increase the risk of subsequent newly diagnosed uterine cancer. It is critical that further large-scale, well-designed studies be conducted to confirm the association between PCOS and gynecological cancer risk. ©AlphaMed Press.

Double jeopardy: the influence of excessive daytime sleepiness and impaired cognition on health-related quality of life in adults with heart failure

PubMed Central

Riegel, Barbara; Ratcliffe, Sarah J.; Weintraub, William S.; Sayers, Steven L.; Goldberg, Lee R.; Potashnik, Sheryl; Weaver, Terri E.; Pressler, Susan J.

2012-01-01

Aims To determine how excessive daytime sleepiness (EDS) and impaired cognition contribute to health-related quality of life (HRQL) in heart failure (HF). Methods and results Adults with chronic HF were enrolled into a prospective cohort study. Data were obtained from 280 subjects enrolled from three sites in the northeastern USA; 242 completed the 6-month study. At baseline, cohorts with and without EDS were identified using the Epworth Sleepiness Scale. Each EDS group was further subdivided into those with and without impaired cognition using a battery of five neuropsychological tests. Two disease-specific measures, the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the Functional Outcomes of Sleep Questionnaire (FOSQ), were used to measure HRQL. General linear modelling of square-transformed variables was used to test the hypothesis that cohort membership was a significant predictor of HRQL. At 6 months the remaining sample was 62.5 [standard deviation (SD) 12] years old, mostly male (63%), white (65%), and functionally compromised [72% New York Heart Association (NYHA) class III/IV]. The cohort with both EDS and impaired cognition had the lowest KCCQ overall summary score (60.5 ± 22.5) compared with the cohort without EDS or impaired cognition (74.6 ± 17.4, P ≤ 0.001). A similar effect was seen on the FOSQ (16.0 ± 2.8 vs. 18.5 ± 2.2, P < 0.001). Conclusion Impaired cognition alone did not explain poor HRQL, but the addition of EDS poses a significant risk for poor HRQL. Interventions designed to influence EDS may improve HRQL in this population. PMID:22510422

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

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

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

The Danish Youth Cohort: characteristics of participants and non-participants and determinants of attrition.

PubMed

Vinther-Larsen, Mathilde; Riegels, Mette; Rod, Morten Hulvej; Schiøtz, Michaela; Curtis, Tine; Grønbaek, Morten

2010-08-01

The aim of this paper is to describe the design and methods used in the Danish Youth Cohort and to give a description of the study participants with special attention to a comparison between participants and non-participants regarding sociodemographic characteristics. A total of 1,945 schools were invited, out of which 506 participated. The participating 7th grades comprised a total of 12,498 responding adolescents. The response rate for the Danish Youth Cohort established in 2005 was 63%. The sample of 12,498 adolescents represents 18.2% of all pupils (n = 68,764) in the 7th grade (mean age: 13.4 years) in Danish schools in 2005. The cohort was followed up in spring 2006 and spring 2007, where the adolescents were in the 8th (mean age: 14.4 years) and 9th (mean age: 15.3 years) grades, respectively. We found that compared with non-participants the participants were significantly more likely to be girls, to be of Danish ethnicity, and to live in one-family houses. Furthermore, participants more often came from families with two or three children, were more likely to have parents with a high occupational status, parents who were married and parents with a higher total income. Loss to follow-up was only associated with adolescents' higher probability of drinking and use of tobacco, and none of the other factors were associated with attrition. The participants in the Danish Youth Cohort represent a great variety of different groups of socio-demographic factors, although they differ from non-participants as regards a range of socio-demographic factors. This should be taken into account in future analyses.

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

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.

The Natural History of the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) Studies: Design and Baseline Characteristics: ProgStar Report No. 1.

PubMed

Strauss, Rupert W; Ho, Alex; Muñoz, Beatriz; Cideciyan, Artur V; Sahel, José-Alain; Sunness, Janet S; Birch, David G; Bernstein, Paul S; Michaelides, Michel; Traboulsi, Elias I; Zrenner, Eberhart; Sadda, SriniVas; Ervin, Ann-Margret; West, Sheila; Scholl, Hendrik P N

2016-04-01

To describe the design and baseline characteristics of patients enrolled into 2 natural history studies of Stargardt disease (STGD1). Multicenter retrospective and prospective cohort studies. Three hundred sixty-five unique patients aged 6 years and older at baseline harboring disease-causing variants in the ABCA4 gene and with specified ocular lesions were enrolled from 9 centers in the United States and Europe. In the retrospective study, patients contributed medical record data from at least 2 and up to 4 visits for at least 1 examination modality: fundus autofluorescence (FAF), spectral-domain (SD) optical coherence tomography (SD OCT), and/or microperimetry (MP). The total observational period was at least 2 years and up to 5 years between single visits. Demographic and visual acuity (VA) data also were obtained. In the prospective study, eligible patients were examined at baseline using a standard protocol, with 6-month follow-up visits planned for a 2-year period for serial Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected VA, SD OCT, FAF, and MP. Design and rationale of a multicenter study to determine the progression of STGD1 in 2 large retrospective and prospective international cohorts. Detailed baseline characteristics of both cohorts are presented, including demographics, and structural and functional retinal metrics. Into the retrospective study, 251 patients (458 eyes) were enrolled; mean follow-up ± standard deviation was 3.9±1.6 years. At baseline, 36% had no or mild VA loss, and 47% of the study eyes had areas of definitely decreased autofluorescence (DDAF) with an average lesion area of 2.5±2.9 mm(2) (range, 0.02-16.03 mm(2)). Two hundred fifty-nine patients (489 eyes) were enrolled in the prospective study. At baseline, 20% had no or mild VA loss, and 64% had areas of DDAF with an average lesion area of 4.0±4.4 mm(2) (range, 0.03-24.24 mm(2)). The mean retinal sensitivity with MP was 10.8±5.0 dB. The ProgStar cohorts have baseline characteristics that encompass a wide range of disease severity and are expected to provide valuable data on progression based on serial quantitative measurements derived from multiple methods, which will be critical to the design of planned clinical trials. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Exploring generational cohort work satisfaction in hospital nurses.

PubMed

Gordon, Pamela Ann

2017-07-03

Purpose Although extensive research exists regarding job satisfaction, many previous studies used a more restrictive, quantitative methodology. The purpose of this qualitative study is to capture the perceptions of hospital nurses within generational cohorts regarding their work satisfaction. Design/methodology/approach A preliminary qualitative, phenomenological study design explored hospital nurses' work satisfaction within generational cohorts - Baby Boomers (1946-1964), Generation X (1965-1980) and Millennials (1981-2000). A South Florida hospital provided the venue for the research. In all, 15 full-time staff nurses, segmented into generational cohorts, participated in personal interviews to determine themes related to seven established factors of work satisfaction: pay, autonomy, task requirements, administration, doctor-nurse relationship, interaction and professional status. Findings An analysis of the transcribed interviews confirmed the importance of the seven factors of job satisfaction. Similarities and differences between the generational cohorts related to a combination of stages of life and generational attributes. Practical implications The results of any qualitative research relate only to the specific venue studied and are not generalizable. However, the information gleaned from this study is transferable and other organizations are encouraged to conduct their own research and compare the results. Originality/value This study is unique, as the seven factors from an extensively used and highly respected quantitative research instrument were applied as the basis for this qualitative inquiry into generational cohort job satisfaction in a hospital setting.

Common Polymorphisms in the PKP3-SIGIRR-TMEM16J Gene Region Are Associated With Susceptibility to Tuberculosis

PubMed Central

Randhawa, April K.; Chau, Tran T. H.; Bang, Nguyen D.; Yen, Nguyen T. B.; Farrar, Jeremy J.; Dunstan, Sarah J.; Hawn, Thomas R.

2012-01-01

(See the editorial commentary by Wilkinson, on pages 525–7.) Background. Tuberculosis has been associated with genetic variation in host immunity. We hypothesized that single-nucleotide polymorphisms (SNPs) in SIGIRR, a negative regulator of Toll-like receptor/IL-1R signaling, are associated with susceptibility to tuberculosis. Methods. We used a case-population study design in Vietnam with cases that had either tuberculous meningitis or pulmonary tuberculosis. We genotyped 6 SNPs in the SIGIRR gene region (including the adjacent genes PKP3 and TMEM16J) in a discovery cohort of 352 patients with tuberculosis and 382 controls. Significant associations were genotyped in a validation cohort (339 patients with tuberculosis, 376 controls). Results. Three SNPs (rs10902158, rs7105848, rs7111432) were associated with tuberculosis in discovery and validation cohorts. The polymorphisms were associated with both tuberculous meningitis and pulmonary tuberculosis and were strongest with a recessive genetic model (odds ratios, 1.5–1.6; P = .0006–.001). Coinheritance of these polymorphisms with previously identified risk alleles in Toll-like receptor 2 and TIRAP was associated with an additive risk of tuberculosis susceptibility. Conclusions. These results demonstrate a strong association of SNPs in the PKP3-SIGIRR-TMEM16J gene region and tuberculosis in discovery and validation cohorts. To our knowledge, these are the first associations of polymorphisms in this region with any disease. PMID:22223854

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

Cohen, Ezra E.W.; Rosine, Dominique; Haraf, Daniel J.

Purpose: Reirradiation (re-RT) with concurrent chemotherapy offers a therapeutic option in patients who have locoregional recurrence of head and neck cancer (HNC). The hypoxic cell sensitizer, tirapazamine (TPZ), has demonstrated promising results in first-line therapy for HNC. This phase I trial was designed to test the feasibility of giving TPZ in the re-RT setting. Methods and Materials: Patients with recurrent HNC who received prior radiotherapy (RT) were enrolled and received TPZ (260 mg/m{sup 2}) and cisplatin (50 mg/m{sup 2}) Weeks 1, 3, and 5 concurrently with RT (72 Gy, 42 fractions over 6 weeks). TPZ (160 mg/m{sup 2}) alone wasmore » added on Days 1, 3, and 5 of Week 2 (cohort 1) or Weeks 2 and 4 (cohort 2). Results: Twenty-five subjects were enrolled, 7 and 18 on cohorts 1 and 2, respectively. Significant toxicities included Grade 3 dermatitis (20%) and Grade 3 mucositis (40%). Dose-limiting toxicity was observed on cohort 2 (1 patient with aspiration pneumonia). Four deaths occurred during treatment. Two fatalities occurred after completing therapy as a result of carotid artery rupture. With a minimum and median follow-up of 14 and 24 months, respectively, median overall survival was 14 months with actuarial 1-year and 2-year survival of 56% and 27%, respectively. Conclusion: Reirradiation with concomitant chemotherapy including TPZ in patients with unresectable recurrent HNC is feasible and results in long-term survival in a significant proportion of patients.« less

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

Cardiac structure and function predicts functional decline in the oldest old.

PubMed

Leibowitz, David; Jacobs, Jeremy M; Lande-Stessman, Irit; Gilon, Dan; Stessman, Jochanan

2018-02-01

Background This study examined the association between cardiac structure and function and the deterioration in activities of daily living (ADLs) in an age-homogenous, community-dwelling population of patients born in 1920-1921 over a five-year follow-up period. Design Longitudinal cohort study. Methods Patients were recruited from the Jerusalem Longitudinal Cohort Study, which has followed an age-homogenous cohort of Jerusalem residents born in 1920-1921. Patients underwent home echocardiography and were followed up for five years. Dependence was defined as needing assistance with one or more basic ADL. Standard echocardiographic assessment of cardiac structure and function, including systolic and diastolic function, was performed. Reassessment of ADLs was performed at the five-year follow-up. Results A total of 459 patients were included in the study. Of these, 362 (79%) showed a deterioration in at least one ADL at follow-up. Patients with functional deterioration had a significantly higher left ventricular mass index and left atrial volume with a lower ejection fraction. There was no significant difference between the diastolic parameters the groups in examined. When the data were examined categorically, a significantly larger percentage of patients with functional decline had an abnormal left ventricular ejection fraction and left ventricular hypertrophy. The association between left ventricular mass index and functional decline remained significant in all multivariate models. Conclusions In this cohort of the oldest old, an elevated left ventricular mass index, higher left atrial volumes and systolic, but not diastolic dysfunction, were predictive of functional disability.

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

Associations between ASA Physical Status and postoperative mortality at 48 h: a contemporary dataset analysis compared to a historical cohort.

PubMed

Hopkins, Thomas J; Raghunathan, Karthik; Barbeito, Atilio; Cooter, Mary; Stafford-Smith, Mark; Schroeder, Rebecca; Grichnik, Katherine; Gilbert, Richard; Aronson, Solomon

2016-01-01

In this study, we examined the association between American Society of Anesthesiologists Physical Status (ASA PS) designation and 48-h mortality for both elective and emergent procedures in a large contemporary dataset (patient encounters between 2009 and 2014) and compared this association with data from a landmark study published by Vacanti et al. in 1970. Patient history, hospital characteristics, anesthetic approach, surgical procedure, efficiency and quality indicators, and patient outcomes were prospectively collected for 732,704 consecutive patient encounters between January 1, 2009, and December 31, 2014, at 233 anesthetizing locations across 19 facilities in two US states and stored in the Quantum™ Clinical Navigation System (QCNS) database. The outcome (death within 48 h of procedure) was tabulated against ASA PS designations separately for patients with and without "E" status labels. To maintain consistency with the historical cohort from the landmark study performed by Vacanti et al. on adult men at US naval hospitals in 1970, we then created a comparison cohort in the contemporary dataset that consisted of 242,103 adult male patients (with/without E designations) undergoing elective and emergent procedures. Differences in the relationship between ASA PS and 48-h mortality in the historical and contemporary cohorts were assessed for patients undergoing elective and emergent procedures. As reported nearly five decades ago, we found a significant trend toward increased mortality with increasing ASA PS for patients undergoing both elective and emergent procedures in a large contemporary cohort ( p  < 0.0001). Additionally, the overall mortality rate at 48 h was significantly higher among patients undergoing emergent compared to elective procedures in the large contemporary cohort (1.27 versus 0.03 %, p  < 0.0001). In the comparative analysis with the historical cohort that focused on adult males, we found the overall 48-h mortality rate was significantly lower among patients undergoing elective procedures in the contemporary cohort (0.05 % now versus 0.24 % in 1970, p  < 0.0001) but not significantly lower among those undergoing emergent procedures (1.88 % now versus 1.22 % in 1970, p  < 0.0001). The association between increasing ASA PS designation (1-5) and mortality within 48 h of surgery is significant for patients undergoing both elective and emergent procedures in a contemporary dataset consisting of over 700,000 patient encounters. Emergency surgery was associated with a higher risk of patient death within 48 h of surgery in this contemporary dataset. These data trends are similar to those observed nearly five decades ago in a landmark study evaluating the association between ASA PS and 48-h surgical mortality on adult men at US naval hospitals. When a comparison cohort was created from the contemporary dataset and compared to this landmark historical cohort, the absolute 48-h mortality rate was significantly lower in the contemporary cohort for elective procedures but not significantly lower for emergency procedures. The underlying implications of these findings remain to be determined.

Examining the pathways for young people with drug and alcohol dependence: a mixed-method design to examine the role of a treatment programme

PubMed Central

Nathan, Sally; Rawstorne, Patrick; Hayen, Andrew; Bryant, Joanne; Baldry, Eileen; Ferry, Mark; Williams, Megan; Shanahan, Marian; Jayasinha, Ranmalie

2016-01-01

Introduction Young people with drug and alcohol problems are likely to have poorer health and other psychosocial outcomes than other young people. Residential treatment programmes have been shown to lead to improved health and related outcomes for young people in the short term. There is very little robust research showing longer term outcomes or benefits of such programmes. This paper describes an innovative protocol to examine the longer term outcomes and experiences of young people referred to a residential life management and treatment programme in Australia designed to address alcohol and drug issues in a holistic manner. Methods and analysis This is a mixed-methods study that will retrospectively and prospectively examine young people's pathways into and out of a residential life management programme. The study involves 3 components: (1) retrospective data linkage of programme data to health and criminal justice administrative data sets, (2) prospective cohort (using existing programme baseline data and a follow-up survey) and (3) qualitative in-depth interviews with a subsample of the prospective cohort. The study will compare findings among young people who are referred and (a) stay 30 days or more in the programme (including those who go on to continuing care and those who do not); (b) start, but stay fewer than 30 days in the programme; (c) are assessed, but do not start the programme. Ethics and dissemination Ethics approval has been sought from several ethics committees including a university ethics committee, state health departments and an Aboriginal-specific ethics committee. The results of the study will be published in peer-reviewed journals, presented at research conferences, disseminated via a report for the general public and through Facebook communications. The study will inform the field more broadly about the value of different methods in evaluating programmes and examining the pathways and trajectories of vulnerable young people. PMID:27225650

Randomized controlled trials and neuro-oncology: should alternative designs be considered?

PubMed

Mansouri, Alireza; Shin, Samuel; Cooper, Benjamin; Srivastava, Archita; Bhandari, Mohit; Kondziolka, Douglas

2015-09-01

Deficiencies in design and reporting of randomized controlled trials (RCTs) hinders interpretability and critical appraisal. The reporting quality of recent RCTs in neuro-oncology was analyzed to assess adequacy of design and reporting. The MEDLINE and EMBASE databases were searched to identify non-surgical RCTs (years 2005-2014, inclusive). The CONSORT and Jadad scales were used to assess the quality of design/reporting. Studies published in 2005-2010 were compared as a cohort against studies published in 2011-2014, in terms of general characteristics and reporting quality. A PRECIS-based scale was used to designate studies on the pragmatic-explanatory continuum. Spearman's test was used to assess correlations. Regression analysis was used to assess associations. Overall 68 RCTs were identified. Studies were often chemotherapy-based (n = 41 studies) focusing upon high grade gliomas (46 %) and metastases (41 %) as the top pathologies. Multi-center trials (71 %) were frequent. The overall median CONSORT and Jadad scores were 34.5 (maximum 44) and 2 (maximum 5), respectively; these scores were similar in radiation and chemotherapy-based trials. Major areas of deficiency pertained to allocation concealment, implementation of methods, and blinding whereby less than 20 % of articles fulfilled all criteria. Description of intervention, random sequence generation, and the details regarding recruitment were also deficient; less than 50 % of studies fulfilled all criteria. Description of sample size calculations and blinding improved in later published cohorts. Journal impact factor was significantly associated with higher quality (p = 0.04). Large academic consortia, multi-center designs, ITT analysis, collaboration with biostatisticians, larger sample sizes, and studies with pragmatic objectives were more likely to achieve positive primary outcomes on univariate analysis; none of these variables were significant on multivariate analysis. Deficiencies in the quality of design/reporting of RCTs in neuro-oncology persist. Quality improvement is necessary. Consideration of alternative strategies should be considered.

Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC): Design and Characteristics of Linked and Unlinked Participants

PubMed Central

Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W.; Krajden, Mel

2016-01-01

Background The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. Methods The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Results Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90–100%). Conclusion Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV. PMID:26954020

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

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

Establishing a birth cohort to investigate the course and aetiology of asthma and allergies across three generations - rationale, design, and methods of the ACROSSOLAR study.

PubMed

Weinmann, Tobias; Gerlich, Jessica; Heinrich, Sabine; Nowak, Dennis; Gerdes, Jennifer; Schlichtiger, Jenny; von Mutius, Erika; Schaub, Bianca; Vogelberg, Christian; Roller, Diana; Radon, Katja

2015-12-04

Atopic diseases are a major burden of disease on a global scale. Regarding their aetiology, the early years of life are assumed to play a crucial role. In addition, there is growing evidence that elucidating the impact of cross-generational effects and epigenetic mechanisms such as DNA methylation can substantially widen the scientific knowledge of the occurrence and progression of these diseases. We are thus aiming at following the course of asthma, allergies, and potential risk factors for their occurrence across three generations by establishing a birth cohort in the offspring of an existing population-based cohort. 2051 young adults who have been recruited in 1995 for Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC) and who have subsequently been followed-up by the Study on Occupational Allergy Risks (SOLAR) are asked bi-annually since 2009 if they conceived a child in the meantime. If parenthood is reported, parents are invited to enrol along with their children in the ACROSSOLAR cohort. Participation involves completing a questionnaire assessing general and health-related information about the course of the pregnancy and the first year of life of their children. Subsequently, the children are followed up until primary school age when asthma and allergies can be diagnosed reliably. In addition, DNA for epigenetic analysis will be collected and analysed. Longitudinal data analysis techniques will then be used to assess potential associations between early-life exposures and onset of childhood asthma and allergies taking into account epigenetics. Birth cohorts are especially suited to elucidate the impact of genetic predisposition, epigenetics, exposures during the first years of life, and gene-environment interactions on the occurrence and progression of asthma and allergies. By building upon an existing cohort, ACROSSOLAR offers a unique and cost-effective opportunity to investigate the aetiology of atopic disease in a prospective and cross-generational way.

Obesity paradox and mortality in adults with and without incident type 2 diabetes: a matched population-level cohort study

PubMed Central

Badrick, Ellena; Sperrin, Matthew; Buchan, Iain E

2017-01-01

Objective Among adults with type 2 diabetes (T2D), several (but not all) studies show that being overweight (body mass index (BMI): 25.0–29.9 kg/m2) or obese I (BMI: 30.0–34.9 kg/m2) near the time of diagnosis, is unexpectedly associated with reduced all-cause mortality compared with normal weight—the obesity paradox. We addressed whether this observation is causal (eg, a true protective effect); due to confounding (including effect modification); or due to selection (‘collider’) bias. Research design and methods We performed a matched population-level cohort study using primary care records from Salford, UK (1995–2012) in 10 464 patients with incident T2D paired (1:3) with 31 020 individuals who never developed T2D. We estimated HRs for associations of BMI with all-cause mortality using Cox models, stratified by smoking status. Results Median follow-up was 8.7 years. For never smokers, the hazard of all-cause mortality increased from 25 kg/m2, in a linear manner, with increasing BMI in the T2D cohort (HR per 5 kg/m2: 1.23, ptrend<0.001) and in the non-diabetes cohort (HR per 5 kg/m2: 1.34, ptrend<0.001). In contrast, among ever smokers, BMI-mortality relationships were U-shaped in the T2D and non-diabetes cohorts. Evidence of the obesity paradox in ever smokers, with and without T2D, argued against a selection bias, but supported a contribution of effect modification by smoking (pinteraction=0.009). Results were stable to various sensitivity analyses. Conclusions In this cohort, the obesity paradox is mainly explained by smoking as an effect modifier. These findings indicate that the obesity paradox does not challenge standard weight management recommendations among T2D patients. PMID:28321314

A brief dietary assessment predicts executive dysfunction in an elderly cohort: results from the Einstein Aging Study

USDA-ARS?s Scientific Manuscript database

Objectives: To examine the association between diet and executive function, episodic memory and global verbal cognition in the Einstein Aging Study (EAS) cohort and determine whether race modifies this relationship. Design: Cross-sectional. Setting: Community. Participants: EAS participants without ...

76 FR 3907 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-21

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Department... for Occupational Safety and Health (NIOSH), 4676 Columbia Parkway, MS C-46, Cincinnati, OH 45226... . John Howard, Director, National Institute for Occupational Safety and Health. [FR Doc. 2011-1228 Filed...

Variation in choice of study design: findings from the Epidemiology Design Decision Inventory and Evaluation (EDDIE) survey.

PubMed

Stang, Paul E; Ryan, Patrick B; Overhage, J Marc; Schuemie, Martijn J; Hartzema, Abraham G; Welebob, Emily

2013-10-01

Researchers using observational data to understand drug effects must make a number of analytic design choices that suit the characteristics of the data and the subject of the study. Review of the published literature suggests that there is a lack of consistency even when addressing the same research question in the same database. To characterize the degree of similarity or difference in the method and analysis choices made by observational database research experts when presented with research study scenarios. On-line survey using research scenarios on drug-effect studies to capture method selection and analysis choices that follow a dependency branching based on response to key questions. Voluntary participants experienced in epidemiological study design solicited for participation through registration on the Observational Medical Outcomes Partnership website, membership in particular professional organizations, or links in relevant newsletters. Description (proportion) of respondents selecting particular methods and making specific analysis choices based on individual drug-outcome scenario pairs. The number of questions/decisions differed based on stem questions of study design, time-at-risk, outcome definition, and comparator. There is little consistency across scenarios, by drug or by outcome of interest, in the decisions made for design and analyses in scenarios using large healthcare databases. The most consistent choice was the cohort study design but variability in the other critical decisions was common. There is great variation among epidemiologists in the design and analytical choices that they make when implementing analyses in observational healthcare databases. These findings confirm that it will be important to generate empiric evidence to inform these decisions and to promote a better understanding of the impact of standardization on research implementation.

Benefits and challenges of using the cohort multiple randomised controlled trial design for testing an intervention for depression.

PubMed

Viksveen, Petter; Relton, Clare; Nicholl, Jon

2017-07-06

Trials which test the effectiveness of interventions compared with the status quo frequently encounter challenges. The cohort multiple randomised controlled trial (cmRCT) design is an innovative approach to the design and conduct of pragmatic trials which seeks to address some of these challenges. In this article, we report our experiences with the first completed randomised controlled trial (RCT) using the cmRCT design. This trial-the Depression in South Yorkshire (DEPSY) trial-involved comparison of treatment as usual (TAU) with TAU plus the offer of an intervention for people with self-reported long-term moderate to severe depression. In the trial, we used an existing large population-based cohort: the Yorkshire Health Study. We discuss our experiences with recruitment, attrition, crossover, data analysis, generalisability of results, and cost. The main challenges in using the cmRCT design were the high crossover to the control group and the lower questionnaire response rate among patients who refused the offer of treatment. However, the design did help facilitate efficient and complete recruitment of the trial population as well as analysable data that were generalisable to the population of interest. Attrition rates were also smaller than those reported in other depression trials. This first completed full trial using the cmRCT design testing an intervention for self-reported depression was associated with a number of important benefits. Further research is required to compare the acceptability and cost effectiveness of standard pragmatic RCT design with the cmRCT design. ISRCTN registry: ISRCTN02484593 . Registered on 7 Jan 2013.

The Alberta moving beyond breast cancer (AMBER) cohort study: a prospective study of physical activity and health-related fitness in breast cancer survivors

PubMed Central

2012-01-01

Background Limited research has examined the association between physical activity, health-related fitness, and disease outcomes in breast cancer survivors. Here, we present the rationale and design of the Alberta Moving Beyond Breast Cancer (AMBER) Study, a prospective cohort study designed specifically to examine the role of physical activity and health-related fitness in breast cancer survivorship from the time of diagnosis and for the balance of life. The AMBER Study will examine the role of physical activity and health-related fitness in facilitating treatment completion, alleviating treatment side effects, hastening recovery after treatments, improving long term quality of life, and reducing the risks of disease recurrence, other chronic diseases, and premature death. Methods/Design The AMBER Study will enroll 1500 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a 5 year period. Assessments will be made at baseline (within 90 days of surgery), 1 year, and 3 years consisting of objective and self-reported measurements of physical activity, health-related fitness, blood collection, lymphedema, patient-reported outcomes, and determinants of physical activity. A final assessment at 5 years will measure patient-reported data only. The cohort members will be followed for an additional 5 years for disease outcomes. Discussion The AMBER cohort will answer key questions related to physical activity and health-related fitness in breast cancer survivors including: (1) the independent and interactive associations of physical activity and health-related fitness with disease outcomes (e.g., recurrence, breast cancer-specific mortality, overall survival), treatment completion rates, symptoms and side effects (e.g., pain, lymphedema, fatigue, neuropathy), quality of life, and psychosocial functioning (e.g., anxiety, depression, self-esteem, happiness), (2) the determinants of physical activity and health-related fitness including demographic, medical, social cognitive, and environmental variables, (3) the mediators of any observed associations between physical activity, health-related fitness, and health outcomes including biological, functional, and psychosocial, and (4) the moderators of any observed associations including demographic, medical, and biological/disease factors. Taken together, these data will provide a comprehensive inquiry into the outcomes, determinants, mechanisms, and moderators of physical activity and health-related fitness in breast cancer survivors. PMID:23153358

Clinical Trials Targeting Aging and Age-Related Multimorbidity

PubMed Central

Crimmins, Eileen M; Grossardt, Brandon R; Crandall, Jill P; Gelfond, Jonathan A L; Harris, Tamara B; Kritchevsky, Stephen B; Manson, JoAnn E; Robinson, Jennifer G; Rocca, Walter A; Temprosa, Marinella; Thomas, Fridtjof; Wallace, Robert; Barzilai, Nir

2017-01-01

Abstract Background There is growing interest in identifying interventions that may increase health span by targeting biological processes underlying aging. The design of efficient and rigorous clinical trials to assess these interventions requires careful consideration of eligibility criteria, outcomes, sample size, and monitoring plans. Methods Experienced geriatrics researchers and clinical trialists collaborated to provide advice on clinical trial design. Results Outcomes based on the accumulation and incidence of age-related chronic diseases are attractive for clinical trials targeting aging. Accumulation and incidence rates of multimorbidity outcomes were developed by selecting at-risk subsets of individuals from three large cohort studies of older individuals. These provide representative benchmark data for decisions on eligibility, duration, and assessment protocols. Monitoring rules should be sensitive to targeting aging-related, rather than disease-specific, outcomes. Conclusions Clinical trials targeting aging are feasible, but require careful design consideration and monitoring rules. PMID:28364543

miR-758-3p: a blood-based biomarker that’s influence on the expression of CERP/ABCA1 may contribute to the progression of obesity to metabolic syndrome

PubMed Central

O’Neill, Sadhbh; Larsen, Mette Bohl; Gregersen, Søren; Hermansen, Kjeld; O’Driscoll, Lorraine

2018-01-01

Due to increasing prevalence of obesity, a simple method or methods for the diagnosis of metabolic syndrome are urgently required to reduce the risk of associated cardiovascular disease, diabetes and cancer. This study aimed to identify a miRNA biomarker that may distinguish metabolic syndrome from obesity and to investigate if such a miRNA may have functional relevance for metabolic syndrome. 52 adults with clinical obesity (n=26) or metabolic syndrome (n=26) were recruited. Plasma specimens were procured from all and were randomly designated to discovery and validation cohorts. miRNA discovery profiling was performed, using array technology, on plasma RNA. Validation was performed by quantitative polymerase chain reaction. The functional effect of miR-758-3p on its predicted target, cholesterol efflux regulatory protein/ATP-binding cassette transporter, was investigated using HepG2 liver cells. Custom miRNA profiling of 25 miRNAs in the discovery cohort found miR-758-3p to be detected in the obese cohort but undetected in the metabolic syndrome cohort. miR-758-3p was subsequently validated as a potential biomarker for metabolic syndrome by quantitative polymerase chain reaction. Bioinformatics analysis identified cholesterol efflux regulatory protein/ATP-binding cassette transporter as miR-758-3p’s predicted target. Specifically, mimicking miR-758-3p in HepG2 cells suppressed cholesterol efflux regulatory protein/ATP-binding cassette transporter protein expression; conversely, inhibiting miR-758-3p increased cholesterol efflux regulatory protein/ATP-binding cassette transporter protein expression. miR-758-3p holds potential as a blood-based biomarker for distinguishing progression from obesity to metabolic syndrome and as a driver in controlling cholesterol efflux regulatory protein/ATP-binding cassette transporter expression, indicating it potential role in cholesterol control in metabolic syndrome. PMID:29507696

miR-758-3p: a blood-based biomarker that's influence on the expression of CERP/ABCA1 may contribute to the progression of obesity to metabolic syndrome.

PubMed

O'Neill, Sadhbh; Larsen, Mette Bohl; Gregersen, Søren; Hermansen, Kjeld; O'Driscoll, Lorraine

2018-02-06

Due to increasing prevalence of obesity, a simple method or methods for the diagnosis of metabolic syndrome are urgently required to reduce the risk of associated cardiovascular disease, diabetes and cancer. This study aimed to identify a miRNA biomarker that may distinguish metabolic syndrome from obesity and to investigate if such a miRNA may have functional relevance for metabolic syndrome. 52 adults with clinical obesity (n=26) or metabolic syndrome (n=26) were recruited. Plasma specimens were procured from all and were randomly designated to discovery and validation cohorts. miRNA discovery profiling was performed, using array technology, on plasma RNA. Validation was performed by quantitative polymerase chain reaction. The functional effect of miR-758-3p on its predicted target, cholesterol efflux regulatory protein/ATP-binding cassette transporter, was investigated using HepG2 liver cells. Custom miRNA profiling of 25 miRNAs in the discovery cohort found miR-758-3p to be detected in the obese cohort but undetected in the metabolic syndrome cohort. miR-758-3p was subsequently validated as a potential biomarker for metabolic syndrome by quantitative polymerase chain reaction. Bioinformatics analysis identified cholesterol efflux regulatory protein/ATP-binding cassette transporter as miR-758-3p's predicted target. Specifically, mimicking miR-758-3p in HepG2 cells suppressed cholesterol efflux regulatory protein/ATP-binding cassette transporter protein expression; conversely, inhibiting miR-758-3p increased cholesterol efflux regulatory protein/ATP-binding cassette transporter protein expression. miR-758-3p holds potential as a blood-based biomarker for distinguishing progression from obesity to metabolic syndrome and as a driver in controlling cholesterol efflux regulatory protein/ATP-binding cassette transporter expression, indicating it potential role in cholesterol control in metabolic syndrome.

A cohort study of Chlamydia trachomatis treatment failure in women: a study protocol

PubMed Central

2013-01-01

Background Chlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in the developed world and diagnosis rates have increased dramatically over the last decade. Repeat infections of chlamydia are very common and may represent re-infection from an untreated partner or treatment failure. The aim of this cohort study is to estimate the proportion of women infected with chlamydia who experience treatment failure after treatment with 1 gram azithromycin. Methods/design This cohort study will follow women diagnosed with chlamydia for up to 56 days post treatment. Women will provide weekly genital specimens for further assay. The primary outcome is the proportion of women who are classified as having treatment failure 28, 42 or 56 days after recruitment. Comprehensive sexual behavior data collection and the detection of Y chromosome DNA and high discriminatory chlamydial genotyping will be used to differentiate between chlamydia re-infection and treatment failure. Azithromycin levels in high-vaginal specimens will be measured using a validated liquid chromatography – tandem mass spectrometry method to assess whether poor azithromycin absorption could be a cause of treatment failure. Chlamydia culture and minimal inhibitory concentrations will be performed to further characterize the chlamydia infections. Discussion Distinguishing between treatment failure and re-infection is important in order to refine treatment recommendations and focus infection control mechanisms. If a large proportion of repeat chlamydia infections are due to antibiotic treatment failure, then international recommendations on chlamydia treatment may need to be re-evaluated. If most are re-infections, then strategies to expedite partner treatment are necessary. PMID:23957327

Recall and Believability of the Tips From Former Smokers Campaign Among University Students

PubMed Central

Ickes, Melinda. J.; Butler, Karen; Rayens, Mary Kay; Noland, Melody; Wiggins, Amanda T.; Hahn, Ellen J.

2016-01-01

Background Tobacco media campaigns are effective, but less is known regarding the impact on college students. Purpose The purpose was to test the effects of an on-campus Tips television campaign on frequency and believability of ads recalled and to assess demographic and personal factors associated with believability. Methods A quasi-experimental pre-post design was used to assess the 8-week campaign with three Tips ads. Two randomly-selected cohorts of college students (N = 1,593) from a large public university completed online surveys pre- and post-campaign. Group comparisons using chi-square tests, two-sample t-tests, and logistic regression, controlling for residence or cohort; predictors of believability using proportional odds modeling. Results Ads were recalled by significantly more students (68%) post-campaign. Believability for one or more ads was lower for males, undergraduates, those belonging to fraternity/sorority, and current polytobacco users (p<.05). Believability was greater for those who recalled seeing the ads more often (p<.05). Discussion Sub-groups of college students, including males and undergraduates, reported less ad believability, which should be considered when designing communication strategies. Translation to Health Education Practice Considering the potential impact and cost-effective nature of on-campus TV media campaigns, these ads need to be integrated into current campus tobacco control strategies. PMID:28396713

Rationale and study design of the Japan environment and children’s study (JECS)

PubMed Central

2014-01-01

Background There is global concern over significant threats from a wide variety of environmental hazards to which children face. Large-scale and long-term birth cohort studies are needed for better environmental management based on sound science. The primary objective of the Japan Environment and Children’s Study (JECS), a nation-wide birth cohort study that started its recruitment in January 2011, is to elucidate environmental factors that affect children’s health and development. Methods/Design Approximately 100,000 expecting mothers who live in designated study areas will be recruited over a 3-year period from January 2011. Participating children will be followed until they reach 13 years of age. Exposure to environmental factors will be assessed by chemical analyses of bio-specimens (blood, cord blood, urine, breast milk, and hair), household environment measurements, and computational simulations using monitoring data (e.g. ambient air quality monitoring) as well as questionnaires. JECS’ priority outcomes include reproduction/pregnancy complications, congenital anomalies, neuropsychiatric disorders, immune system disorders, and metabolic/endocrine system disorders. Genetic factors, socioeconomic status, and lifestyle factors will also be examined as covariates and potential confounders. To maximize representativeness, we adopted provider-mediated community-based recruitment. Discussion Through JECS, chemical substances to which children are exposed during the fetal stage or early childhood will be identified. The JECS results will be translated to better risk assessment and management to provide healthy environment for next generations. PMID:24410977

Human papillomavirus (HPV) perinatal transmission and risk of HPV persistence among children: Design, methods and preliminary results of the HERITAGE study.

PubMed

Trottier, Helen; Mayrand, Marie-Hélène; Coutlée, François; Monnier, Patricia; Laporte, Louise; Niyibizi, Joseph; Carceller, Ana-Maria; Fraser, William D; Brassard, Paul; Lacroix, Jacques; Francoeur, Diane; Bédard, Marie-Josée; Girard, Isabelle; Audibert, François

2016-12-01

Perinatal route of transmission of human papillomavirus (HPV) has been demonstrated in several small studies. We designed a large prospective cohort study (HERITAGE) to better understand perinatal HPV. The objective of this article is to present the study design and preliminary data. In the first phase of the study, we recruited 167 women in Montreal, Canada, during the first trimester of pregnancy. An additional 850 are currently being recruited in the ongoing phase. Cervicovaginal samples were obtained from mothers in the first trimester and tested for HPV DNA from 36 mucosal genotypes (and repeated in the third trimester for HPV-positive mothers). Placental samples were also taken for HPV DNA testing. Conjunctival, oral, pharyngeal and genital samples were collected for HPV DNA testing in children of HPV-positive mothers at every 3-6 months from birth until 2 years of age. Blood samples were collected in mother and children for HPV serology testing. We found a high prevalence of HPV in pregnant women (45%[95%CI:37-53%]) and in placentas (14%[8-21%]). The proportion of HPV positivity (any site) among children at birth/3-months was 11%[5-22%]. HPV was detected in children in multiple sites including the conjunctiva (5%[10-14%]). The ongoing HERITAGE cohort will help provide a better understanding of perinatal HPV. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

The human early-life exposome (HELIX): project rationale and design.

PubMed

Vrijheid, Martine; Slama, Rémy; Robinson, Oliver; Chatzi, Leda; Coen, Muireann; van den Hazel, Peter; Thomsen, Cathrine; Wright, John; Athersuch, Toby J; Avellana, Narcis; Basagaña, Xavier; Brochot, Celine; Bucchini, Luca; Bustamante, Mariona; Carracedo, Angel; Casas, Maribel; Estivill, Xavier; Fairley, Lesley; van Gent, Diana; Gonzalez, Juan R; Granum, Berit; Gražulevičienė, Regina; Gutzkow, Kristine B; Julvez, Jordi; Keun, Hector C; Kogevinas, Manolis; McEachan, Rosemary R C; Meltzer, Helle Margrete; Sabidó, Eduard; Schwarze, Per E; Siroux, Valérie; Sunyer, Jordi; Want, Elizabeth J; Zeman, Florence; Nieuwenhuijsen, Mark J

2014-06-01

Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure-health effect relationships. The "exposome" concept encompasses the totality of exposures from conception onward, complementing the genome. The Human Early-Life Exposome (HELIX) project is a new collaborative research project that aims to implement novel exposure assessment and biomarker methods to characterize early-life exposure to multiple environmental factors and associate these with omics biomarkers and child health outcomes, thus characterizing the "early-life exposome." Here we describe the general design of the project. In six existing birth cohort studies in Europe, HELIX will estimate prenatal and postnatal exposure to a broad range of chemical and physical exposures. Exposure models will be developed for the full cohorts totaling 32,000 mother-child pairs, and biomarkers will be measured in a subset of 1,200 mother-child pairs. Nested repeat-sampling panel studies (n = 150) will collect data on biomarker variability, use smartphones to assess mobility and physical activity, and perform personal exposure monitoring. Omics techniques will determine molecular profiles (metabolome, proteome, transcriptome, epigenome) associated with exposures. Statistical methods for multiple exposures will provide exposure-response estimates for fetal and child growth, obesity, neurodevelopment, and respiratory outcomes. A health impact assessment exercise will evaluate risks and benefits of combined exposures. HELIX is one of the first attempts to describe the early-life exposome of European populations and unravel its relation to omics markers and health in childhood. As proof of concept, it will form an important first step toward the life-course exposome.

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.

Cost effectiveness of total knee arthroplasty from a health care providers' perspective before and after introduction of an interdisciplinary clinical pathway - is investment always improvement?

PubMed Central

2011-01-01

Background Total knee arthroplasty (TKA) is an effective, but also cost-intensive health care intervention for end stage osteoarthritis. This investigation was designed to evaluate the cost-effectiveness of TKA before versus after introduction of an interdisciplinary clinical pathway from a University Orthopedic Surgery Department's cost perspective as an interdisciplinary full service health care provider. Methods A prospective trial recruited two sequential cohorts of 132 and 128 consecutive patients, who were interviewed by means of the WOMAC questionnaire. Direct process costs from the health care providers' perspective were estimated according to the German DRG calculation framework. The health economic evaluation was based on margiual cost-effectveness ratios (MCERs); an individual marginal cost effectiveness relation ≤ 100 € per % WOMAC index increase was considered as primary endpoint of the confirmatory cohort comparison. The interdisciplinary clinical pathway under consideration primarily consisted of a voluntary preoperative personal briefing of patients concerning postoperatively expectable progess in health status and optimum use of walking aids after surgery. All patients were supplied with written information on these topics, attendance of the personal briefing also included preoperative training for postoperative mobilisation by the Department's physiotherapeutic staff. Results An individual marginal cost effectiveness relation ≤ 100 €/% WOMAC index increase was found in 38% of the patients in the pre pathway implementation cohort versus in 30% of the post pathway implementation cohort (Fisher p = 0.278). Both cohorts showed substantial improvement in WOMAC scores (39 versus 35% in median), whereas the cohort did not differ significantly in the median WOMAC score before surgery (41% for the pre pathway cohort versus 44% for the post pathway cohort). Despite a locally significant decrease in costs (4303 versus 4194 € in median), the individual cost/benefit relation became worse after introduction of the pathway: for the first cohort the MCER was estimated 108 € per gained % WOMAC index increase (86 - 150 €/%) versus 118 €/% WOMAC gain (93 - 173 €/%) in the second cohort after pathway implementation. In summary, the proposed critical pathway for TKA could be shown to be significantly cost efficient, but not cost effective concerning functional outcome, when the above individual marginal cost effectiveness criterion was concentrated on. Conclusions The introduction of an interdisciplinary clinical pathway does not necessarily improve patient related outcomes. On the contrary, cost effectiveness from the health care providers' perspective may even turn out remarkably reduced in the setting considered here (functional outcome assessment after treatment by a full service health care provider). PMID:22168149

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.

Exchangeability in the case-crossover design

PubMed Central

Mittleman, Murray A; Mostofsky, Elizabeth

2014-01-01

In cohort and case-control studies, confounding that arises as a result of differences in the distribution of determinants of the outcome between exposure groups leading to non-exchangeability are addressed by restriction, matching or with statistical models. In case-only studies, this issue is addressed by comparing each individual with his/herself. Although case-only designs use self-matching and only include individuals who develop the outcome of interest, issues of non-exchangeability are identical to those that arise in traditional case-control and cohort studies. In this review, we describe one type of case-only design, the case-crossover design, and discuss how the concept of exchangeability can be used to understand issues of confounding, carryover effects, period effects and selection bias in case-crossover studies. PMID:24756878

A Comparison of Liver Disease Mortality With HIV and Overdose Mortality Among Georgia Prisoners and Releasees: A 2-Decade Cohort Study of Prisoners Incarcerated in 1991

PubMed Central

Sharma, Akshay; Messina, Lauren C.; Zlotorzynska, Maria; Miller, Lesley; Binswanger, Ingrid A.

2015-01-01

Objectives. We investigated whether eventual causes of death among a cohort of inmates imprisoned in the southeastern United States differed from those in previous prisoner studies. Methods. We matched 23 510 prisoners in Georgia, a state with historically low levels of heroin consumption but moderate amounts of injection drug use, who were incarcerated on June 30, 1991, to death registries through 2010. Main exposure was 4-year time intervals over 2 decades of observation; main outcome was mortality from liver disease, HIV, and overdose. Results. Although the HIV-related mortality rate exceeded that from liver-related conditions before 2003, liver disease subsequently surpassed HIV as a cause of death. Among 3863 deaths, 22 (0.6%) occurred within 2 weeks after release from prison. Of these, only 2 were caused by accidental poisoning (likely drug overdose). Cardiovascular disease and cancer were the most frequent causes of death in this aging cohort. Conclusions. Our study design deemphasized immediate deaths but highlighted long-term sequelae of exposure to viral hepatitis and alcohol. Treating hepatitis C and implementing interventions to manage alcohol use disorders may improve survival among prisoners in the Southeast. PMID:25790417

Using social-emotional and character development to improve academic outcomes: a matched-pair, cluster-randomized controlled trial in low-income, urban schools

PubMed Central

Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.

2013-01-01

BACKGROUND School-based social-emotional and character development (SECD) programs can influence not only SECD, but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. METHODS The longitudinal study used a matched-pair, cluster-randomized controlled design. Student-reported disaffection with learning and academic grades, and teacher ratings of academic ability and motivation were assessed for a cohort followed from grades 3 to 8. Aggregate school records were used to assess standardized test performance (for entire school, cohort, and demographic subgroups) and absenteeism (entire school). Multilevel growth-curve analyses tested program effects. RESULTS PA significantly improved growth in academic motivation and mitigated disaffection with learning. There was a positive impact of PA on absenteeism and marginally significant impact on math performance of all students. There were favorable program effects on reading for African American boys and cohort students transitioning between grades 7 and 8, and on math for girls and low-income students. CONCLUSIONS A school-based SECD program was found to influence academic outcomes among students living in low-income, urban communities. Future research should examine mechanisms by which changes in SECD influence changes in academic outcomes. PMID:24138347

Elevated Maternal C-Reactive Protein is Associated with Increased Risk of Schizophrenia in a National Birth Cohort

PubMed Central

Canetta, Sarah; Sourander, Andre; Surcel, Helja-Marja; Hinkka-Yli-Salomäki, Susanna; Leiviskä, Jaana; Kellendonk, Christoph; McKeague, Ian W.; Brown, Alan S.

2014-01-01

Objective The goal of the present study was to investigate an association between early gestational C-reactive protein (CRP), an established inflammatory biomarker, prospectively assayed in maternal sera, and schizophrenia in a large national birth cohort with an extensive serum biobank. Methods This study utilized a nested case-control design from the Finnish Prenatal Study of Schizophrenia cohort. 777 schizophrenia cases (630 with schizophrenia, 147 with schizoaffective disorder) that had maternal sera available for CRP testing were identified and matched to 777 controls in the analysis. Maternal CRP levels were assessed using a latex immunoassay from archived maternal serum specimens. Results Increasing maternal CRP levels, classified as a continuous variable, were significantly associated with schizophrenia in offspring (adjusted odds ratio (OR)=1.31, 95% confidence interval (CI)=1.10-1.56, p=0.003). This finding remained significant after adjusting for potential confounders including maternal and parental history of psychiatric disorders, twin/singleton birth, urbanicity, province of birth, and maternal socioeconomic status. Conclusion This finding provides the most robust evidence to date that maternal inflammation may play a significant role in schizophrenia, with possible implications for identifying preventive strategies and pathogenic mechanisms in schizophrenia and other neurodevelopmental disorders. PMID:24969261

Are flexibility and muscle-strengthening activities associated with a higher risk of developing low back pain?

PubMed Central

Sandler, Robert D.; Sui, Xuemei; Church, Timothy S.; Fritz, Stacy L.; Beattie, Paul F.; Blair, Steven N.

2013-01-01

Objective To examine the association between participation in flexibility or muscle-strengthening activities with the development of low back pain (LBP). Design Observational cohort study. Methods The cohort included 4,610 adults, 17% female, between 20 and 81 years of age (mean 46.6, s.d. 4.96). The cohort was followed for a mean of 4.9 years for self-reported LBP. All participants reported at baseline whether they performed flexibility or muscle-strengthening activities, including specific sub-types. Results Neither general performance of flexibility or muscle-strengthening activities were associated with a higher incidence of LBP compared to those who did not perform these activities. Those who reported stretching, as a specific flexibility activity were at a higher risk of developing LBP compared with those who performed no flexibility exercises, reported calisthenic flexibility activities, or attended exercise classes. Those who reported using weight training machines, as part of muscle-strengthening activities, had a higher risk of reporting LBP, compared with those who did not perform muscle-strengthening activities or performed calisthenic or free weight activities. Conclusion In this sample, stretching or use of weight training machines is associated with increased risk of developing LBP compared to use of free weights, calisthenics or flexibility classes. PMID:23988784

A patient-centered electronic tool for weight loss outcomes after Roux-en-Y gastric bypass.

PubMed

Wood, G Craig; Benotti, Peter; Gerhard, Glenn S; Miller, Elaina K; Zhang, Yushan; Zaccone, Richard J; Argyropoulos, George A; Petrick, Anthony T; Still, Christopher D

2014-01-01

BACKGROUND. Current patient education and informed consent regarding weight loss expectations for bariatric surgery candidates are largely based on averages from large patient cohorts. The variation in weight loss outcomes illustrates the need for establishing more realistic weight loss goals for individual patients. This study was designed to develop a simple web-based tool which provides patient-specific weight loss expectations. METHODS. Postoperative weight measurements after Roux-en-Y gastric bypass (RYGB) were collected and analyzed with patient characteristics known to influence weight loss outcomes. Quantile regression was used to create expected weight loss curves (25th, 50th, and 75th %tile) for the 24 months after RYGB. The resulting equations were validated and used to develop web-based tool for predicting weight loss outcomes. RESULTS. Weight loss data from 2986 patients (2608 in the primary cohort and 378 in the validation cohort) were included. Preoperative body mass index (BMI) and age were found to have a high correlation with weight loss accomplishment (P < 0.0001 for each). An electronic tool was created that provides easy access to patient-specific, 24-month weight loss trajectories based on initial BMI and age. CONCLUSIONS. This validated, patient-centered electronic tool will assist patients and providers in patient teaching, informed consent, and postoperative weight loss management.

Determinants of health after hospital discharge: rationale and design of the Vanderbilt Inpatient Cohort Study (VICS)

PubMed Central

2014-01-01

Background The period following hospital discharge is a vulnerable time for patients when errors and poorly coordinated care are common. Suboptimal care transitions for patients admitted with cardiovascular conditions can contribute to readmission and other adverse health outcomes. Little research has examined the role of health literacy and other social determinants of health in predicting post-discharge outcomes. Methods The Vanderbilt Inpatient Cohort Study (VICS), funded by the National Institutes of Health, is a prospective longitudinal study of 3,000 patients hospitalized with acute coronary syndromes or acute decompensated heart failure. Enrollment began in October 2011 and is planned through October 2015. During hospitalization, a set of validated demographic, cognitive, psychological, social, behavioral, and functional measures are administered, and health status and comorbidities are assessed. Patients are interviewed by phone during the first week after discharge to assess the quality of hospital discharge, communication, and initial medication management. At approximately 30 and 90 days post-discharge, interviewers collect additional data on medication adherence, social support, functional status, quality of life, and health care utilization. Mortality will be determined with up to 3.5 years follow-up. Statistical models will examine hypothesized relationships of health literacy and other social determinants on medication management, functional status, quality of life, utilization, and mortality. In this paper, we describe recruitment, eligibility, follow-up, data collection, and analysis plans for VICS, as well as characteristics of the accruing patient cohort. Discussion This research will enhance understanding of how health literacy and other patient factors affect the quality of care transitions and outcomes after hospitalization. Findings will help inform the design of interventions to improve care transitions and post-discharge outcomes. PMID:24397292

The German Chronic Kidney Disease (GCKD) study: design and methods.

PubMed

Eckardt, Kai-Uwe; Bärthlein, Barbara; Baid-Agrawal, Seema; Beck, Andreas; Busch, Martin; Eitner, Frank; Ekici, Arif B; Floege, Jürgen; Gefeller, Olaf; Haller, Hermann; Hilge, Robert; Hilgers, Karl F; Kielstein, Jan T; Krane, Vera; Köttgen, Anna; Kronenberg, Florian; Oefner, Peter; Prokosch, Hans-Ulrich; Reis, André; Schmid, Matthias; Schaeffner, Elke; Schultheiss, Ulla T; Seuchter, Susanne A; Sitter, Thomas; Sommerer, Claudia; Walz, Gerd; Wanner, Christoph; Wolf, Gunter; Zeier, Martin; Titze, Stephanie

2012-04-01

Chronic kidney disease (CKD) is increasingly recognized as a global health problem. The conditions leading to CKD, the health impact of CKD and the prognosis differ markedly between affected individuals. In particular, renal failure and cardiovascular mortality are competing risks for CKD patients. Opportunities for targeted intervention are very limited so far and require an improved understanding of the natural course of CKD, of the risk factors associated with various clinical end points and co-morbidities as well as of the underlying pathogenic mechanisms. The German Chronic Kidney Disease (GCKD) study is a prospective observational national cohort study. It aims to enrol a total of 5000 patients with CKD of various aetiologies, who are under nephrological care, and to follow them for up to 10 years. At the time of enrolment, male and female patients have an estimated glomerular filtration rate (eGFR) of 30-60 mL/min×1.73 m2 or overt proteinuria in the presence of an eGFR>60 mL/min×1.73 m2. Standardized collection of biomaterials, including DNA, serum, plasma and urine will allow identification and validation of biomarkers associated with CKD, CKD progression and related complications using hypothesis-driven and hypothesis-free approaches. Patient recruitment and follow-up is organized through a network of academic nephrology centres collaborating with practising nephrologists throughout the country. The GCKD study will establish one of the largest cohorts to date of CKD patients not requiring renal replacement therapy. Similarities in its design with other observational CKD studies, including cohorts that have already been established in the USA and Japan, will allow comparative and joint analyses to identify important ethnic and geographic differences and to enhance opportunities for identification of relevant risk factors and markers.

Associations of welding and manganese exposure with Parkinson disease

PubMed Central

Borenstein, Amy R.; Nelson, Lorene M.

2012-01-01

Objective: To examine associations of welding and manganese exposure with Parkinson disease (PD) using meta-analyses of data from cohort, case-control, and mortality studies. Methods: Epidemiologic studies related to welding or manganese exposure and PD were identified in a PubMed search, article references, published reviews, and abstracts. Inclusion criteria were 1) cohort, case-control, or mortality study with relative risk (RR), odds ratio (OR), or mortality OR (MOR) and 95 confidence intervals (95% CI); 2) RR, OR, and MOR matched or adjusted for age and sex; 3) valid study design and analysis. When participants of a study were a subgroup of those in a larger study, only results of the larger study were included to assure independence of datasets. Pooled RR/OR estimates and 95% CIs were obtained using random effects models; heterogeneity of study effects were evaluated using the Q statistic and I2 index in fixed effect models. Results: Thirteen studies met inclusion criteria for the welding meta-analysis and 3 studies for the manganese exposure meta-analysis. The pooled RR for the association between welding and PD for all study designs was 0.86 (95% CI 0.80–0.92), with absence of between-study heterogeneity (I2 = 0.0). Effect measures for cohort, case-control, and mortality studies were similar (0.91, 0.82, 0.87). For the association between manganese exposure and PD, the pooled OR was 0.76 (95% CI 0.41–1.42). Conclusions: Welding and manganese exposure are not associated with increased PD risk. Possible explanations for the inverse association between welding and PD include confounding by smoking, healthy worker effect, and hormesis. PMID:22965675

Soy intake is associated with lower lung cancer risk: results from a meta-analysis of epidemiologic studies123

PubMed Central

Yang, Wan-Shui; Va, Puthiery; Wong, Man-Yu; Zhang, Huan-Ling

2011-01-01

Background: Although several in vitro and animal in vivo studies have suggested that soy or soy isoflavones may exert inhibitory effects on lung carcinogenesis, epidemiologic studies have reported inconclusive results on the association between soy intake and lung cancer. Objective: The aim of this meta-analysis was to investigate whether an association exists between soy and lung cancer in epidemiologic studies. Design: We searched PubMed, EMBASE, and the Cochrane Library from their inception to February 2011 for both case-control and cohort studies that assessed soy consumption and lung cancer risk. Study-specific risk estimates were combined by using fixed-effect or random-effect models. Results: A total of 11 epidemiologic studies that consisted of 8 case-control and 3 prospective cohort studies were included. A significantly inverse association was shown between soy intake and lung cancer with an overall RR of 0.77 (95% CI: 0.65, 0.92). Findings were slightly different when analyses were restricted to 5 high-quality studies (RR: 0.70; 95% CI: 0.45, 0.99). In a subgroup meta-analysis, a statistically significant protective effect of soy consumption was observed in women (RR: 0.79; 95% CI: 0.67, 0.93), never smokers (RR: 0.62; 95% CI: 0.51, 0.76), and Asian populations (RR: 0.86; 95% CI: 0.74, 0.98). Conclusions: Our findings indicate that the consumption of soy food is associated with lower lung cancer risk. Because of different methods used to assess soy consumption across studies, more well-designed cohort studies or intervention studies that use unified measures of soy intake are needed to fully characterize such an association. PMID:22071712

XRCC1 Polymorphism Associated With Late Toxicity After Radiation Therapy in Breast Cancer Patients

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

Seibold, Petra; Behrens, Sabine; Schmezer, Peter

Purpose: To identify single-nucleotide polymorphisms (SNPs) in oxidative stress–related genes associated with risk of late toxicities in breast cancer patients receiving radiation therapy. Methods and Materials: Using a 2-stage design, 305 SNPs in 59 candidate genes were investigated in the discovery phase in 753 breast cancer patients from 2 prospective cohorts from Germany. The 10 most promising SNPs in 4 genes were evaluated in the replication phase in up to 1883 breast cancer patients from 6 cohorts identified through the Radiogenomics Consortium. Outcomes of interest were late skin toxicity and fibrosis of the breast, as well as an overall toxicity score (Standardized Totalmore » Average Toxicity). Multivariable logistic and linear regression models were used to assess associations between SNPs and late toxicity. A meta-analysis approach was used to summarize evidence. Results: The association of a genetic variant in the base excision repair gene XRCC1, rs2682585, with normal tissue late radiation toxicity was replicated in all tested studies. In the combined analysis of discovery and replication cohorts, carrying the rare allele was associated with a significantly lower risk of skin toxicities (multivariate odds ratio 0.77, 95% confidence interval 0.61-0.96, P=.02) and a decrease in Standardized Total Average Toxicity scores (−0.08, 95% confidence interval −0.15 to −0.02, P=.016). Conclusions: Using a stage design with replication, we identified a variant allele in the base excision repair gene XRCC1 that could be used in combination with additional variants for developing a test to predict late toxicities after radiation therapy in breast cancer patients.« less

Prospective Observational Study of Implantable Cardioverter‐Defibrillators in Primary Prevention of Sudden Cardiac Death: Study Design and Cohort Description

PubMed Central

Cheng, Alan; Dalal, Darshan; Butcher, Barbara; Norgard, Sanaz; Zhang, Yiyi; Dickfeld, Timm; Eldadah, Zayd A.; Ellenbogen, Kenneth A.; Guallar, Eliseo; Tomaselli, Gordon F.

2013-01-01

Background Primary‐prevention implantable cardioverter‐defibrillators (ICDs) reduce total mortality in patients with severe left ventricular systolic function. However, only a minority of patients benefit from these devices. We designed the Prospective Observational Study of Implantable Cardioverter‐Defibrillators (PROSE‐ICD) to identify risk factors and enhance our understanding of the biological mechanisms that predispose to arrhythmic death in patients undergoing ICD implantation for primary prevention of sudden death. Methods and Results This is a multicenter prospective cohort study with a target enrollment of 1200 patients. The primary end point is ICD shocks for adjudicated ventricular tachyarrhythmias. The secondary end point is total mortality. All patients undergo a comprehensive evaluation including history and physical examination, signal‐averaged electrocardiograms, and blood sampling for genomic, proteomic, and metabolomic analyses. Patients are evaluated every 6 months and after every known ICD shock for additional electrocardiographic and blood sampling. As of December 2011, a total of 1177 patients have been enrolled with more nonwhite and female patients compared to previous randomized trials. A total of 143 patients have reached the primary end point, whereas a total of 260 patients died over an average follow‐up of 59 months. The PROSE‐ICD study represents a real‐world cohort of individuals with systolic heart failure receiving primary‐prevention ICDs. Conclusions Extensive electrophysiological and structural phenotyping as well as the availability of serial DNA and serum samples will be important resources for evaluating novel metrics for risk stratification and identifying patients at risk for arrhythmic sudden death. Clinical Trial Registration URL: http://clinicaltrials.gov/ Unique Identifier: NCT00733590. PMID:23525420

The Women and Their Children’s Health (WaTCH) study: methods and design of a prospective cohort study in Louisiana to examine the health effects from the BP oil spill

PubMed Central

Rung, Ariane L; Bronson, Megan H; Brashear, Meghan M; Peres, Lauren C; Gaston, Symielle; Sullivan, Samaah M; Peak, Kate; Abramson, David M; Fontham, Elizabeth T H; Harrington, Daniel; Oral, Evrim; Trapido, Edward J

2017-01-01

Purpose The Deepwater Horizon Oil Spill is the largest marine oil spill in US history. Few studies have evaluated the potential health effects of this spill on the Gulf Coast community. The Women and Their Children’s Health (WaTCH) study is a prospective cohort designed to investigate the midterm to long-term physical, mental and behavioural health effects of exposure to the oil spill. Participants Women were recruited by telephone from pre-existing lists of individuals and households using an address-based sampling frame between 2012 and 2014. Baseline interviews obtained information on oil spill exposure, demographics, physical and mental health, and health behaviours. Women were also asked to provide a household roster, from which a child between 10 and 17 years was randomly selected and recruited into a child substudy. Telephone respondents were invited to participate in a home visit in which blood samples, anthropometrics and neighbourhood characteristics were measured. A follow-up interview was completed between 2014 and 2016. Findings to date 2852 women completed the baseline interview, 1231 of whom participated in the home visit, and 628 children participated in the child’s health substudy. The follow-up interview successfully reinterviewed 2030 women and 454 children. Future plans WaTCH continues to conduct follow-up surveys, with a third wave of interviews planned in 2017. Also, we are looking to enhance the collection of spatially related environmental data to facilitate assessment of health risks in the study population. In addition, opportunities to participate in behavioural interventions for subsets of the cohort have been initiated. There are ongoing studies that examine the relationship between genetic and immunological markers with mental health. PMID:28698324

HIV and risk of cardiovascular disease in sub-Saharan Africa: Rationale and design of the Ndlovu Cohort Study.

PubMed

Vos, Alinda; Tempelman, Hugo; Devillé, Walter; Barth, Roos; Wensing, Annemarie; Kretzschmar, Mirjam; Klipstein-Grobusch, Kerstin; Hoepelman, Andy; Tesselaar, Kiki; Aitken, Sue; Madzivhandila, Mashudu; Uiterwaal, Cuno; Venter, Francois; Coutinho, Roel; Grobbee, Diederick E

2017-07-01

Background The largest proportion of people living with HIV resides in sub-Saharan Africa (SSA). Evidence from developed countries suggests that HIV infection increases the relative risk of cardiovascular disease (CVD) by up to 50%. Differences in lifestyle, gender distribution, routes of HIV transmission and HIV subtype preclude generalisation of data from Western countries to the SSA situation. The Ndlovu Cohort Study aims to provide insight into the burden of cardiovascular risk factors and disease, the mechanisms driving CVD risk and the contribution of HIV infection and its treatment to the development of CVD in a rural area of SSA. Design The Ndlovu Cohort Study is a prospective study in the Moutse area, Limpopo Province, South Africa. Methods A total of 1000 HIV-positive and 1000 HIV-negative participants aged 18 years and older with a male to female ratio of 1:1 will be recruited. Measurements of CVD risk factors and HIV-related characteristics will be performed at baseline, and participants will be followed-up over time at 6-month intervals. The burden of CVD will be assessed with repeated carotid intima-media thickness and pulse wave velocity measurements, as well as by recording clinical cardiovascular events that occur during the follow-up period. Conclusion This project will contribute to the understanding of the epidemiology and pathogenesis of CVD in the context of HIV infection in a rural area of SSA. The ultimate goal is to improve cardiovascular risk prediction and to indicate preventive approaches in the HIV-infected population and, potentially, for non-infected high-risk populations in a low-resource setting.

Gender-Specific Combination HIV Prevention for Youth in High-Burden Settings: The MP3 Youth Observational Pilot Study Protocol

PubMed Central

Agot, Kawango

2017-01-01

Background Nearly three decades into the epidemic, sub-Saharan Africa (SSA) remains the region most heavily affected by human immunodeficiency virus (HIV), with nearly 70% of the 34 million people living with HIV globally residing in the region. In SSA, female and male youth (15 to 24 years) are at a disproportionately high risk of HIV infection compared to adults. As such, there is a need to target HIV prevention strategies to youth and to tailor them to a gender-specific context. This protocol describes the process for the multi-staged approach in the design of the MP3 Youth pilot study, a gender-specific, combination, HIV prevention intervention for youth in Kenya. Objective The objective of this multi-method protocol is to outline a rigorous and replicable methodology for a gender-specific combination HIV prevention pilot study for youth in high-burden settings, illustrating the triangulated methods undertaken to ensure that age, sex, and context are integral in the design of the intervention. Methods The mixed-methods, cross-sectional, longitudinal cohort pilot study protocol was developed by first conducting a systematic review of the literature, which shaped focus group discussions around prevention package and delivery options, and that also informed age- and sex- stratified mathematical modeling. The review, qualitative data, and mathematical modeling created a triangulated evidence base of interventions to be included in the pilot study protocol. To design the pilot study protocol, we convened an expert panel to select HIV prevention interventions effective for youth in SSA, which will be offered in a mobile health setting. The goal of the pilot study implementation and evaluation is to apply lessons learned to more effective HIV prevention evidence and programming. Results The combination HIV prevention package in this protocol includes (1) offering HIV testing and counseling for all youth; (2) voluntary medical circumcision and condoms for males; (3) pre-exposure prophylaxis (PrEP), conditional cash transfer (CCT), and contraceptives for females; and (4) referrals for HIV care among those identified as HIV-positive. The combination package platform selected is mobile health teams in an integrated services delivery model. A cross-sectional analysis will be conducted to determine the uptake of the interventions. To determine long-term impact, the protocol outlines enrolling selected participants in mutually exclusive longitudinal cohorts (HIV-positive, PrEP, CCT, and HIV-negative) followed by using mobile phone text messages (short message service, SMS) and in-person surveys to prospectively assess prevention method uptake, adherence, and risk compensation behaviors. Cross-sectional and sub-cohort analyses will be conducted to determine intervention packages uptake. Conclusions The literature review, focus groups, and modeling indicate that offering age- and gender- specific combination HIV prevention interventions that include biomedical, behavioral, and structural interventions can have an impact on HIV risk reduction. Implementing this protocol will show the feasibility of delivering these services at scale. The MP3 Youth study is one of the few combination HIV prevention intervention protocols incorporating youth- and gender-specific interventions in one delivery setting. Lessons learned from the design of the protocol can be incorporated into the national guidance for combination HIV prevention for youth in Kenya and other high-burden SSA settings. Trial Registration ClinicalTrials.gov NCT01571128; http://clinicaltrials.gov/ct2/show/NCT01571128?term=MP3+youth&rank=1 (Archived by WebCite at http://www.webcitation.org/6nmioPd54) PMID:28274904

Literacy Learning Cohorts: Content-Focused Approach to Improving Special Education Teachers' Reading Instruction

ERIC Educational Resources Information Center

Brownell, Mary; Kiely, Mary Theresa; Haager, Diane; Boardman, Alison; Corbett, Nancy; Algina, James; Dingle, Mary Patricia; Urbach, Jennifer

2017-01-01

Two professional development (PD) models for teachers were compared on teacher and student outcomes. Special education teachers participated in Literacy Learning Cohorts (LLC), a PD innovation designed to improve content and pedagogical knowledge for providing reading instruction to upper elementary students with learning disabilities. The LLC,…

Correlation between Sustainability Education and Engineering Students' Attitudes towards Sustainability

ERIC Educational Resources Information Center

Tang, Kuok Ho Daniel

2018-01-01

Purpose: The purpose of this study is to investigate the impacts of a sustainable development course on the beliefs, attitudes and intentions of a cohort of engineering students in a university in Miri, Malaysia, towards sustainability. Design/methodology/approach: Questionnaire survey was conducted among the cohort of students encompassing the…

Using Multiple Imputation to Assign Pesticide Use for Non-Responders in the Follow-Up Questionnaire in the Agricultural Health Study

EPA Science Inventory

The Agricultural Health Study (AHS), a large prospective cohort, was designed to elucidate associations between pesticide use and other agricultural exposures and health outcomes. The cohort includes 57,310 pesticide applicators who were enrolled between 1993 and 1997 in Iowa and...

76 FR 51035 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-17

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Department... Mexico, from January 1, 1949 through December 31, 1962, for a number of work days aggregating at least..., Division of Compensation Analysis and Support, National Institute for Occupational Safety and Health (NIOSH...

77 FR 58382 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Centers for... aggregating at least 250 work days, occurring either solely under this employment, or in combination with work[email protected] . John Howard, Director, National Institute for Occupational Safety and Health. [FR Doc. 2012...

77 FR 58382 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Centers for... predecessor agencies, and their contractors and subcontractors who worked at the Hanford Engineer Works in... at least 250 work days, occurring either solely under this employment or in combination with work...

76 FR 26299 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Department... at least 250 work days, occurring either solely under this employment, or in combination with work... Safety and Health (NIOSH), 4676 Columbia Parkway, MS C-46, Cincinnati, OH 45226, Telephone 877-222-7570...

Clinical Research Methodology 2: Observational Clinical Research.

PubMed

Sessler, Daniel I; Imrey, Peter B

2015-10-01

Case-control and cohort studies are invaluable research tools and provide the strongest feasible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. Observational studies are subject to errors attributable to selection bias, confounding, measurement bias, and reverse causation-in addition to errors of chance. Confounding can be statistically controlled to the extent that potential factors are known and accurately measured, but, in practice, bias and unknown confounders usually remain additional potential sources of error, often of unknown magnitude and clinical impact. Causality-the most clinically useful relation between exposure and outcome-can rarely be definitively determined from observational studies because intentional, controlled manipulations of exposures are not involved. In this article, we review several types of observational clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects.

Observational methods to assess the effectiveness of screening colonoscopy in reducing right colon cancer mortality risk: SCOLAR.

PubMed

Goodman, Michael; Fletcher, Robert H; Doria-Rose, V Paul; Jensen, Christopher D; Zebrowski, Alexis M; Becerra, Tracy A; Quinn, Virginia P; Zauber, Ann G; Corley, Douglas A; Doubeni, Chyke A

2015-11-01

Screening colonoscopy's effectiveness in reducing risk of death from right colon cancers remains unclear. Methodological challenges of existing observational studies addressing this issue motivated the design of 'Effectiveness of Screening for Colorectal Cancer in Average-Risk Adults (SCOLAR)'. SCOLAR is a nested case-control study based on two large integrated health systems. This affords access to a large, well-defined historical cohort linked to integrated data on cancer outcomes, patient eligibility, test indications and important confounders. We found electronic data adequate for excluding ineligible patients (except family history), but not the detailed information needed for test indication assignment. The lessons of SCOLAR's design and implementation may be useful for future studies seeking to evaluate the effectiveness of screening tests in community settings.

A multinational clinical approach to assessing the effectiveness of catheter-based ultrasound renal denervation: The RADIANCE-HTN and REQUIRE clinical study designs.

PubMed

Mauri, Laura; Kario, Kazuomi; Basile, Jan; Daemen, Joost; Davies, Justin; Kirtane, Ajay J; Mahfoud, Felix; Schmieder, Roland E; Weber, Michael; Nanto, Shinsuke; Azizi, Michel

2018-01-01

Catheter-based renal denervation is a new approach to treat hypertension via modulation of the renal sympathetic nerves. Although nonrandomized and small, open-label randomized studies resulted in significant reductions in office blood pressure 6months after renal denervation with monopolar radiofrequency catheters, the first prospective, randomized, sham-controlled study (Symplicity HTN-3) failed to meet its blood pressure efficacy end point. New clinical trials with new catheters have since been designed to address the limitations of earlier studies. Accordingly, the RADIANCE-HTN and REQUIRE studies are multicenter, blinded, randomized, sham-controlled trials designed to assess the blood pressure-lowering efficacy of the ultrasound-based renal denervation system (Paradise) in patients with established hypertension either on or off antihypertensive medications, is designed to evaluate patients in 2 cohorts-SOLO and TRIO, in the United States and Europe. The SOLO cohort includes patients with essential hypertension, at low cardiovascular risk, and either controlled on 1 to 2 antihypertensive medications or uncontrolled on 0 to 2 antihypertensive medications. Patients undergo a 4-week medication washout period before randomization to renal denervation (treatment) or renal angiogram (sham). The TRIO cohort includes patients with hypertension resistant to at least 3 antihypertensive drugs including a diuretic. Patients will be stabilized on a single-pill, triple-antihypertensive-drug combination for 4weeks before randomization to treatment or sham. Reduction in daytime ambulatory systolic blood pressure (primary end point) will be assessed at 2months in both cohorts. A predefined medication escalation protocol, as needed for blood pressure control, is implemented between 2 and 6months in both cohorts by a study staff member blinded to the randomization process. At 6months, daytime ambulatory blood pressure and antihypertensive treatment score will be assessed. REQUIRE is designed to evaluate patients with resistant hypertension on standard of care medication in Japan and Korea. Reduction in 24-hour ambulatory systolic blood pressure will be assessed at 3months (primary end point). Both studies are enrolling patients, and their results are expected in 2018. Copyright © 2017 Elsevier Inc. All rights reserved.

Social cohesion through football: a quasi-experimental mixed methods design to evaluate a complex health promotion program.

PubMed

Nathan, Sally; Bunde-Birouste, Anne; Evers, Clifton; Kemp, Lynn; MacKenzie, Julie; Henley, Robert

2010-10-05

Social isolation and disengagement fragments local communities. Evidence indicates that refugee families are highly vulnerable to social isolation in their countries of resettlement. Research to identify approaches to best address this is needed. Football United is a program that aims to foster social inclusion and cohesion in areas with high refugee settlement in New South Wales, Australia, through skills and leadership development, mentoring, and the creation of links with local community and corporate leaders and organisations. The Social Cohesion through Football study's broad goal is to examine the implementation of a complex health promotion program, and to analyse the processes involved in program implementation. The study will consider program impact on individual health and wellbeing, social inclusion and cohesion, as well as analyse how the program by necessity interacts and adapts to context during implementation, a concept we refer to as plasticity. The proposed study will be the first prospective cohort impact study to our knowledge to assess the impact of a comprehensive integrated program using football as a vehicle for fostering social inclusion and cohesion in communities with high refugee settlement. A quasi-experimental cohort study design with treatment partitioning involving four study sites. The study employs a 'dose response' model, comparing those with no involvement in the Football United program with those with lower or higher levels of participation. A range of qualitative and quantitative measures will be used in the study. Study participants' emotional well being, resilience, ethnic identity and other group orientation, feelings of social inclusion and belonging will be measured using a survey instrument complemented by relevant data drawn from in-depth interviews, self reporting measures and participant observation. The views of key informants from the program and the wider community will also be solicited. The complexity of the Football United program poses challenges for measurement, and requires the study design to be responsive to the dynamic nature of the program and context. Assessment of change is needed at multiple levels, drawing on mixed methods and multidisciplinary approaches in implementation and evaluation. Attention to these challenges has underpinned the design and methods in the Social Cohesion through Football study, which will use a unique and innovative combination of measures that have not been applied together previously in social inclusion/cohesion and sport and social inclusion/cohesion program research.

Developing a science teacher education course that supports student teachers' thinking and teaching about the nature of science

NASA Astrophysics Data System (ADS)

Sorensen, Pete; Newton, Len; McCarthy, Sue

2012-04-01

Background and purpose . This paper reports on part of an ongoing research project in England concerning the Nature of Science (NOS). The particular focus is on the initial thinking of the graduate scientists starting a one-year, Postgraduate Certificate of Education (PGCE) course and the way the course approaches adopted influence their views and understanding of NOS and their teaching. The research is set against a wealth of literature indicating that teachers find it difficult to teach curricula that emphasise NOS. Thus a key impetus for research in this area has been to look for ways that beginning teachers might be better prepared to face such challenges. Sample The paper draws on data from three cohorts of secondary PGCE students in a university-schools partnership, involving a total of 169 students. Design and method The research lies within a design research tradition. It has used mixed methods, involving written tasks, interviews and focus groups, with an iterative approach where the outcomes from one cohort have been used to inform course developments in successive years. Results The results from these cohorts suggest that, while the students starting the course have a less restricted view of NOS than indicated by some other studies, in most cases there is a lack of breadth and depth to their understanding. There is some evidence that the use of specific tasks focusing on NOS in university-based sessions may be helping to develop and deepen understanding. However, the impact of current approaches remains fairly limited and attempts to develop teaching practices often face considerable barriers in the school-based practicum. Conclusions Graduate science students' understanding of NOS as they embark on the PGCE is not highly developed. Hence, the emphasis on aspects of NOS in the school curriculum presents a considerable challenge. This study suggests that there is a need to both further develop an explicit focus on NOS in university-based sessions and to develop closer relationships between schools and university faculty in seeking to support developments in classroom practice in this difficult area.

Phase II Trial of Atezolizumab As First-Line or Subsequent Therapy for Patients With Programmed Death-Ligand 1-Selected Advanced Non-Small-Cell Lung Cancer (BIRCH).

PubMed

Peters, Solange; Gettinger, Scott; Johnson, Melissa L; Jänne, Pasi A; Garassino, Marina C; Christoph, Daniel; Toh, Chee Keong; Rizvi, Naiyer A; Chaft, Jamie E; Carcereny Costa, Enric; Patel, Jyoti D; Chow, Laura Q M; Koczywas, Marianna; Ho, Cheryl; Früh, Martin; van den Heuvel, Michel; Rothenstein, Jeffrey; Reck, Martin; Paz-Ares, Luis; Shepherd, Frances A; Kurata, Takayasu; Li, Zhengrong; Qiu, Jiaheng; Kowanetz, Marcin; Mocci, Simonetta; Shankar, Geetha; Sandler, Alan; Felip, Enriqueta

2017-08-20

Purpose BIRCH was designed to examine the efficacy of atezolizumab, a humanized anti-programmed death-ligand 1 (PD-L1) monoclonal antibody, in advanced non-small-cell lung cancer (NSCLC) across lines of therapy. Patients were selected on the basis of PD-L1 expression on tumor cells (TC) or tumor-infiltrating immune cells (IC). Patients and Methods Eligible patients had advanced-stage NSCLC, no CNS metastases, and zero to two or more lines of prior chemotherapy. Patients whose tumors expressed PD-L1 using the SP142 immunohistochemistry assay on ≥ 5% of TC or IC (TC2/3 or IC2/3 [TC or IC ≥ 5% PD-L1-expressing cells, respectively]) were enrolled. Atezolizumab 1,200 mg was administered intravenously every 3 weeks. Efficacy-evaluable patients (N = 659) comprised three cohorts: first line (cohort 1; n = 139); second line (cohort 2; n = 268); and third line or higher (cohort 3; n = 252). The primary end point was independent review facility-assessed objective response rate (ORR; Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1). Secondary end points included median duration of response, progression-free survival, and overall survival (OS). Results BIRCH met its primary objective of demonstrating a significant ORR versus historical controls. With a minimum of 12 months of follow-up, the independent review facility-assessed ORR was 18% to 22% for the three cohorts, and 26% to 31% for the TC3 or IC3 subgroup; most responses are ongoing. Responses occurred regardless of EGFR or KRAS mutation status. The median OS from an updated survival analysis (minimum of 20 month follow up) for cohort 1 was 23.5 months (26.9 months for TC3 or IC3 patients); the median OS in cohorts 2 and 3 was 15.5 and 13.2 months, respectively. The safety profile was similar across cohorts and consistent with previous atezolizumab monotherapy trials. Conclusion BIRCH demonstrated responses with atezolizumab monotherapy in patients with PD-L1-selected advanced NSCLC, with good tolerability. PD-L1 status may serve as a predictive biomarker for identifying patients most likely to benefit from atezolizumab.

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

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.…

Patient-Level DNA Damage and Repair Pathway Profiles and Prognosis After Prostatectomy for High-Risk Prostate Cancer

PubMed Central

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.

2017-01-01

IMPORTANCE 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. OBJECTIVE To create a DNA damage and repair (DDR) pathway profiling method for use as a prognostic signature biomarker in high-risk prostate cancer. DESIGN, SETTING, AND PARTICIPANTS 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. MAIN OUTCOMES AND MEASURES Biochemical recurrence-free, metastasis-free, and overall survival. RESULTS 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. CONCLUSIONS AND RELEVANCE 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. PMID:26746117

The QUALYOR (QUalité Osseuse LYon Orléans) study: a new cohort for non invasive evaluation of bone quality in postmenopausal osteoporosis. Rationale and study design.

PubMed

Chapurlat, Roland; Pialat, Jean-Baptiste; Merle, Blandine; Confavreux, Elisabeth; Duvert, Florence; Fontanges, Elisabeth; Khacef, Farida; Peres, Sylvie Loiseau; Schott, Anne-Marie; Lespessailles, Eric

2017-12-27

The diagnostic performance of densitometry is inadequate. New techniques of non-invasive evaluation of bone quality may improve fracture risk prediction. Testing the value of these techniques is the goal of the QUALYOR cohort. The bone mineral density (BMD) of postmenopausal women who sustain osteoporotic fracture is generally above the World Health Organization definition for osteoporosis. Therefore, new approaches to improve the detection of women at high risk for fracture are warranted. We have designed and recruited a new cohort to assess the predictive value of several techniques to assess bone quality, including high-resolution peripheral quantitative computerized tomography (HRpQCT), hip QCT, calcaneus texture analysis, and biochemical markers. We have enrolled 1575 postmenopausal women, aged at least 50, with an areal BMD femoral neck or lumbar spine T-score between - 1.0 and - 3.0. Clinical risk factors for fracture have been collected along with serum and blood samples. We describe the design of the QUALYOR study. Among these 1575 women, 80% were aged at least 60. The mean femoral neck T-score was - 1.6 and the mean lumbar spine T-score was -1.2. This cohort is currently being followed up. QUALYOR will provide important information on the relationship between bone quality variables and fracture risk in women with moderately decreased BMD.

European Birth Cohorts for Environmental Health Research

PubMed Central

Casas, Maribel; Bergström, Anna; Carmichael, Amanda; Cordier, Sylvaine; Eggesbø, Merete; Eller, Esben; Fantini, Maria P.; Fernández, Mariana F.; Fernández-Somoano, Ana; Gehring, Ulrike; Grazuleviciene, Regina; Hohmann, Cynthia; Karvonen, Anne M.; Keil, Thomas; Kogevinas, Manolis; Koppen, Gudrun; Krämer, Ursula; Kuehni, Claudia E.; Magnus, Per; Majewska, Renata; Andersen, Anne-Marie Nybo; Patelarou, Evridiki; Petersen, Maria Skaalum; Pierik, Frank H.; Polanska, Kinga; Porta, Daniela; Richiardi, Lorenzo; Santos, Ana Cristina; Slama, Rémy; Sram, Radim J.; Thijs, Carel; Tischer, Christina; Toft, Gunnar; Trnovec, Tomáš; Vandentorren, Stephanie; Vrijkotte, Tanja G.M.; Wilhelm, Michael; Wright, John; Nieuwenhuijsen, Mark

2011-01-01

Background: Many pregnancy and birth cohort studies investigate the health effects of early-life environmental contaminant exposure. An overview of existing studies and their data is needed to improve collaboration, harmonization, and future project planning. Objectives: Our goal was to create a comprehensive overview of European birth cohorts with environmental exposure data. Methods: Birth cohort studies were included if they a) collected data on at least one environmental exposure, b) started enrollment during pregnancy or at birth, c) included at least one follow-up point after birth, d) included at least 200 mother–child pairs, and e) were based in a European country. A questionnaire collected information on basic protocol details and exposure and health outcome assessments, including specific contaminants, methods and samples, timing, and number of subjects. A full inventory can be searched on www.birthcohortsenrieco.net. Results: Questionnaires were completed by 37 cohort studies of > 350,000 mother–child pairs in 19 European countries. Only three cohorts did not participate. All cohorts collected biological specimens of children or parents. Many cohorts collected information on passive smoking (n = 36), maternal occupation (n = 33), outdoor air pollution (n = 27), and allergens/biological organisms (n = 27). Fewer cohorts (n = 12–19) collected information on water contamination, ionizing or nonionizing radiation exposures, noise, metals, persistent organic pollutants, or other pollutants. All cohorts have information on birth outcomes; nearly all on asthma, allergies, childhood growth and obesity; and 26 collected information on child neurodevelopment. Conclusion: Combining forces in this field will yield more efficient and conclusive studies and ultimately improve causal inference. This impressive resource of existing birth cohort data could form the basis for longer-term and worldwide coordination of research on environment and child health. PMID:21878421

Roogle: an information retrieval engine for clinical data warehouse.

PubMed

Cuggia, Marc; Garcelon, Nicolas; Campillo-Gimenez, Boris; Bernicot, Thomas; Laurent, Jean-François; Garin, Etienne; Happe, André; Duvauferrier, Régis

2011-01-01

High amount of relevant information is contained in reports stored in the electronic patient records and associated metadata. R-oogle is a project aiming at developing information retrieval engines adapted to these reports and designed for clinicians. The system consists in a data warehouse (full-text reports and structured data) imported from two different hospital information systems. Information retrieval is performed using metadata-based semantic and full-text search methods (as Google). Applications may be biomarkers identification in a translational approach, search of specific cases, and constitution of cohorts, professional practice evaluation, and quality control assessment.

Back Complaints in the Elders (BACE); design of cohort studies in primary care: an international consortium

PubMed Central

2011-01-01

Background Although back complaints are common among older people, limited information is available in the literature about the clinical course of back pain in older people and the identification of older persons at risk for the transition from acute back complaints to chronic back pain. The aim of this study is to assess the course of back complaints and identify prognostic factors for the transition from acute back complaints to chronic back complaints in older people who visit a primary health care physician. Methods/design The design is a prospective cohort study with one-year follow-up. There will be no interference with usual care. Patients older than 55 years who consult a primary health care physician with a new episode of back complaints will be included in this study. Data will be collected using a questionnaire, physical examination and X-ray at baseline, and follow-up questionnaires after 6 weeks and 3, 6, 9 and 12 months. The study 'Back Complaints in the Elders' (BACE) will take place in different countries: starting in the Netherlands, Brazil and Australia. The research groups collaborate in the BACE consortium. The design and basic objectives of the study will be the same across the studies. Discussion This consortium is a collaboration between different research groups, aiming to provide insight into the course of back complaints in older people and to identify prognostic factors for the transition from acute back complaints to chronic back complaints in older persons. The BACE consortium allows to investigate differences between older people with back complaints and the health care systems in the different countries and to increase the statistical power by enabling meta-analyses using the individual patient data. Additional research groups worldwide are invited to join the BACE consortium. PMID:21854620

Identifying Neck and Back Pain in Administrative Data: Defining the right cohort

PubMed Central

Siroka, Andrew M.; Shane, Andrea C.; Trafton, Jodie A.; Wagner, Todd H.

2017-01-01

Structured Abstract Study design We reviewed existing methods for identifying patients with neck and back pain in administrative data. We compared these methods using data from the Department of Veterans Affairs. Objective To answer the following questions: 1) what diagnosis codes should be used to identify patients with neck and back pain in administrative data; 2) because the majority of complaints are characterized as non-specific or mechanical, what diagnosis codes should be used to identify patients with non-specific or mechanical problems in administrative data; and 3) what procedure and surgical codes should be used to identify patients who have undergone a surgical procedure on the neck or back. Summary of background data Musculoskeletal neck and back pain are pervasive problems, associated with chronic pain, disability, and high rates of healthcare utilization. Administrative data have been widely used in formative research which has largely relied on the original work of Volinn, Cherkin, Deyo and Einstadter and the Back Pain Patient Outcomes Assessment Team first published in 1992. Significant variation in reports of incidence, prevalence, and morbidity associated with these problems may be due to non standard or conflicting methods to define study cohorts. Methods A literature review produced seven methods for identifying neck and back pain in administrative data. These code lists were used to search VA data for patients with back and neck problems, and to further categorize each case by spinal segment involved, as non- specific/mechanical and as surgical or not. Results There is considerable overlap in most algorithms. However, gaps remain. Conclusions Gaps are evident in existing methods and a new framework to identify patients with neck and back pain in administrative data is proposed. PMID:22127268

Provision of No-Cost, Long-Acting Contraception and Teenage Pregnancy

PubMed Central

Secura, Gina M.; Madden, Tessa; McNicholas, Colleen; Mullersman, Jennifer; Buckel, Christina M.; Zhao, Qiuhong; Peipert, Jeffrey F.

2014-01-01

Background The rate of teenage pregnancy in the United States is higher than in other developed nations. Teenage births result in substantial costs, including public assistance, health care costs, and income losses due to lower educational attainment and reduced earning potential. Methods The Contraceptive CHOICE Project was a large prospective cohort study designed to promote the use of long-acting, reversible contraceptive (LARC) methods to reduce unintended pregnancy in the St. Louis region. Participants were educated about reversible contraception, with an emphasis on the benefits of LARC methods, were provided with their choice of reversible contraception at no cost, and were followed for 2 to 3 years. We analyzed pregnancy, birth, and induced-abortion rates among teenage girls and women 15 to 19 years of age in this cohort and compared them with those observed nationally among U.S. teens in the same age group. Results Of the 1404 teenage girls and women enrolled in CHOICE, 72% chose an intrauterine device or implant (LARC methods); the remaining 28% chose another method. During the 2008–2013 period, the mean annual rates of pregnancy, birth, and abortion among CHOICE participants were 34.0, 19.4, and 9.7 per 1000 teens, respectively. In comparison, rates of pregnancy, birth, and abortion among sexually experienced U.S. teens in 2008 were 158.5, 94.0, and 41.5 per 1000, respectively. Conclusions Teenage girls and women who were provided contraception at no cost and educated about reversible contraception and the benefits of LARC methods had rates of pregnancy, birth, and abortion that were much lower than the national rates for sexually experienced teens. (Funded by the Susan Thompson Buffett Foundation and others.) PMID:25271604

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

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

Tracking of Medicine Use and Self-Medication From Infancy to Adolescence: 1993 Pelotas (Brazil) Birth Cohort Study

PubMed Central

Bertoldi, Andréa Dâmaso; Telis Silveira, Marysabel Pinto; Menezes, Ana M.B.; Formoso Assunção, Maria Cecília; Gonçalves, Helen; Hallal, Pedro Curi

2012-01-01

Purpose To track the use of medicine and self-medication from infancy to adolescence. Methods All newborns in the city of Pelotas, Brazil, were monitored and enrolled in the 1993 Pelotas (Brazil) Birth Cohort Study. Subsamples of the cohort were visited at 1, 3, and 6 months and at 1 and 4 years of age. At 11 and 15 years of age, all cohort members were sought. In each of these visits, information on medicine use in the 15 days before the interview was collected. Two outcomes were analyzed: prevalence of medicine use and prevalence of self-medication. Results Prevalence of medicine use in the first year of life ranged from 52.0% to 68.6%. From 4 to 15 years of age, the prevalence decreased, ranging from 30.9% to 37.2%. At age 15, girls presented a 33% higher prevalence of medicine use than boys. The proportion of self-medication ranged from 12.4% to 29.0% and was higher in girls aged 11 and 15 years than boys of the same age. In all follow-up periods, use of medicines was significantly higher among children who used medicines in the earlier period. Prevalence of self-medication was higher among those who were self-medicated in the previous periods. Conclusions Tracking studies are important to public health because they can predict future behavior by analyzing past behavior, thus helping in designing preventive actions. In this study, previous use of medicines predicts future use, thus creating an opportunity to plan actions that promote the rational use of medicines. PMID:23283153

Patterns and Prevalence of Arrest in a Statewide Cohort of Mental Health Care Consumers

PubMed Central

Fisher, William H.; Roy-Bujnowski, Kristen M.; Grudzinskas, Albert J.; Clayfield, Jonathan C.; Banks, Steven M.; Wolff, Nancy

2010-01-01

Objective Although criminal justice involvement among persons with severe mental illness is a much discussed topic, few large-scale studies systematically describe the patterns and prevalence of arrest in this population. This study examined rates, patterns, offenses, and sociodemographic correlates of arrest in a large cohort of mental health service recipients. Methods The arrest records of 13,816 individuals receiving services from the Massachusetts Department of Mental Health from 1991 to 1992 were examined over roughly a ten-year period. Bivariate relationships between sociodemographic factors and arrest were also examined. Results About 28 percent of the cohort experienced at least one arrest. The most common charges were crimes against public order followed by serious violent offenses and minor property crime. The number of arrests per individual ranged from one to 71. Five percent of arrestees (roughly 1.5 percent of the cohort) accounted for roughly 17 percent of arrests. The proportion of men arrested was double that of women. Persons 18 to 25 years of age had a 50 percent chance of at least one arrest. This rate declined with age but did so unevenly across offense types. Conclusions The likelihood of arrest appeared substantial among persons with severe mental illness, but the bulk of offending appeared concentrated in a small group of persons and among persons with sociodemographic features similar to those of offenders in the general population. Data such as these could provide a platform for designing jail diversion and other services to reduce both initial and repeat offending among persons with serious mental illness. PMID:17085611

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.

77 FR 32640 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

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77 FR 38835 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

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77 FR 58381 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

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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

The Tohoku Medical Megabank Project: Design and Mission.

PubMed

Kuriyama, Shinichi; Yaegashi, Nobuo; Nagami, Fuji; Arai, Tomohiko; Kawaguchi, Yoshio; Osumi, Noriko; Sakaida, Masaki; Suzuki, Yoichi; Nakayama, Keiko; Hashizume, Hiroaki; Tamiya, Gen; Kawame, Hiroshi; Suzuki, Kichiya; Hozawa, Atsushi; Nakaya, Naoki; Kikuya, Masahiro; Metoki, Hirohito; Tsuji, Ichiro; Fuse, Nobuo; Kiyomoto, Hideyasu; Sugawara, Junichi; Tsuboi, Akito; Egawa, Shinichi; Ito, Kiyoshi; Chida, Koichi; Ishii, Tadashi; Tomita, Hiroaki; Taki, Yasuyuki; Minegishi, Naoko; Ishii, Naoto; Yasuda, Jun; Igarashi, Kazuhiko; Shimizu, Ritsuko; Nagasaki, Masao; Koshiba, Seizo; Kinoshita, Kengo; Ogishima, Soichi; Takai-Igarashi, Takako; Tominaga, Teiji; Tanabe, Osamu; Ohuchi, Noriaki; Shimosegawa, Toru; Kure, Shigeo; Tanaka, Hiroshi; Ito, Sadayoshi; Hitomi, Jiro; Tanno, Kozo; Nakamura, Motoyuki; Ogasawara, Kuniaki; Kobayashi, Seiichiro; Sakata, Kiyomi; Satoh, Mamoru; Shimizu, Atsushi; Sasaki, Makoto; Endo, Ryujin; Sobue, Kenji; Tohoku Medical Megabank Project Study Group, The; Yamamoto, Masayuki

2016-09-05

The Great East Japan Earthquake (GEJE) and resulting tsunami of March 11, 2011 gave rise to devastating damage on the Pacific coast of the Tohoku region. The Tohoku Medical Megabank Project (TMM), which is being conducted by Tohoku University Tohoku Medical Megabank Organization (ToMMo) and Iwate Medical University Iwate Tohoku Medical Megabank Organization (IMM), has been launched to realize creative reconstruction and to solve medical problems in the aftermath of this disaster. We started two prospective cohort studies in Miyagi and Iwate Prefectures: a population-based adult cohort study, the TMM Community-Based Cohort Study (TMM CommCohort Study), which will recruit 80 000 participants, and a birth and three-generation cohort study, the TMM Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study), which will recruit 70 000 participants, including fetuses and their parents, siblings, grandparents, and extended family members. The TMM CommCohort Study will recruit participants from 2013 to 2016 and follow them for at least 5 years. The TMM BirThree Cohort Study will recruit participants from 2013 to 2017 and follow them for at least 4 years. For children, the ToMMo Child Health Study, which adopted a cross-sectional design, was also started in November 2012 in Miyagi Prefecture. An integrated biobank will be constructed based on the two prospective cohort studies, and ToMMo and IMM will investigate the chronic medical impacts of the GEJE. The integrated biobank of TMM consists of health and clinical information, biospecimens, and genome and omics data. The biobank aims to establish a firm basis for personalized healthcare and medicine, mainly for diseases aggravated by the GEJE in the two prefectures. Biospecimens and related information in the biobank will be distributed to the research community. TMM itself will also undertake genomic and omics research. The aims of the genomic studies are: 1) to construct an integrated biobank; 2) to return genomic research results to the participants of the cohort studies, which will lead to the implementation of personalized healthcare and medicine in the affected areas in the near future; and 3) to contribute the development of personalized healthcare and medicine worldwide. Through the activities of TMM, we will clarify how to approach prolonged healthcare problems in areas damaged by large-scale disasters and how useful genomic information is for disease prevention.

The SLUScore: A Novel Method for Detecting Hazardous Hypotension in Adult Patients Undergoing Noncardiac Surgical Procedures

PubMed Central

Yuan, Hui; Dryden, Jefferson K.; Strehl, Kristen E.; Cywinski, Jacek B.; Ehrenfeld, Jesse M.; Bromley, Pamela

2017-01-01

BACKGROUND: It has been suggested that longer-term postsurgical outcome may be adversely affected by less than severe hypotension under anesthesia. However, evidence-based guidelines are unavailable. The present study was designed to develop a method for identifying patients at increased risk of death within 30 days in association with the severity and duration of intraoperative hypotension. METHODS: Intraoperative mean arterial blood pressure recordings of 152,445 adult patients undergoing noncardiac surgery were analyzed for periods of time accumulated below each one of the 31 thresholds between 75 and 45 mm Hg (hypotensive exposure times). In a development cohort of 35,904 patients, the associations were sought between each of these 31 cumulative hypotensive exposure times and 30-day postsurgical mortality. On the basis of covariable-adjusted percentage increases in the odds of mortality per minute elapsed of hypotensive exposure time, certain sets of exposure time limits were calculated that portended certain percentage increases in the odds of mortality. A novel risk-scoring method was conceived by counting the number of exposure time limits that had been exceeded within each respective set, one of them being called the SLUScore. The validity of this new method in identifying patients at increased risk was tested in a multicenter validation cohort consisting of 116,541 patients from Cleveland Clinic, Vanderbilt and Saint Louis Universities. Data were expressed as 95% confidence interval, P < .05 considered significant. RESULTS: Progressively greater hypotensive exposures were associated with greater 30-day mortality. In the development cohort, covariable-adjusted (age, Charlson score, case duration, history of hypertension) exposure limits were identified for time accumulated below each of the thresholds that portended certain identical (5%–50%) percentage expected increases in the odds of mortality. These exposure time limit sets were shorter in patients with a history of hypertension. A novel risk score, the SLUScore (range 0–31), was conceived as the number of exposure limits exceeded for one of these sets (20% set). A SLUScore > 0 (average 13.8) was found in 40% of patients who had twice the mortality, adjusted odds increasing by 5% per limit exceeded. When tested in the validation cohort, a SLUScore > 0 (average 14.1) identified 35% of patients who had twice the mortality, each incremental limit exceeded portending a 5% compounding increase in adjusted odds of mortality, independent of age and Charlson score (C = 0.73, 0.72–0.74, P < .05). CONCLUSIONS: The SLUScore represents a novel method for identifying nearly 1 in every 3 patients experiencing greater 30-day mortality portended by more severe intraoperative hypotensive exposures. PMID:28107274

The impact of constructivist teaching strategies on the acquisition of higher order cognition and learning

NASA Astrophysics Data System (ADS)

Merrill, Alison Saricks

The purpose of this quasi-experimental quantitative mixed design study was to compare the effectiveness of brain-based teaching strategies versus a traditional lecture format in the acquisition of higher order cognition as determined by test scores. A second purpose was to elicit student feedback about the two teaching approaches. The design was a 2 x 2 x 2 factorial design study with repeated measures on the last factor. The independent variables were type of student, teaching method, and a within group change over time. Dependent variables were a between group comparison of pre-test, post-test gain scores and a within and between group comparison of course examination scores. A convenience sample of students enrolled in medical-surgical nursing was used. One group (n=36) was made up of traditional students and the other group (n=36) consisted of second-degree students. Four learning units were included in this study. Pre- and post-tests were given on the first two units. Course examinations scores from all four units were compared. In one cohort two of the units were taught via lecture format and two using constructivist activities. These methods were reversed for the other cohort. The conceptual basis for this study derives from neuroscience and cognitive psychology. Learning is defined as the growth of new dendrites. Cognitive psychologists view learning as a constructive activity in which new knowledge is built on an internal foundation of existing knowledge. Constructivist teaching strategies are designed to stimulate the brain's natural learning ability. There was a statistically significant difference based on type of teaching strategy (t = -2.078, df = 270, p = .039, d = .25)) with higher mean scores on the examinations covering brain-based learning units. There was no statistical significance based on type of student. Qualitative data collection was conducted in an on-line forum at the end of the semester. Students had overall positive responses about the constructivist activities. Major themes were described. Constructivist strategies help bridge the gap between neurological and cognitive sciences and classroom teaching and learning. A variety of implications for nursing educators are outlined as well as directions for future research.

The Swiss Cystic Fibrosis Infant Lung Development (SCILD) cohort.

PubMed

Korten, Insa; Kieninger, Elisabeth; Yammine, Sophie; Regamey, Nicolas; Nyilas, Sylvia; Ramsey, Kathryn; Casaulta, Carmen; Latzin, Philipp; For The Scild Study Group

2018-04-26

The Swiss Cystic Fibrosis Infant Lung Development (SCILD) cohort is a prospective birth cohort study investigating the initiating events of cystic fibrosis lung disease during infancy, and their influence on the trajectory of disease progression throughout early childhood. Infants with cystic fibrosis are recruited throughout Switzerland after diagnosis by new-born screening. It is the first European population-based prospective cohort study of infants with cystic fibrosis taking advantage of a nationwide new-born screening programme. The study was established in 2011 and recruitment is ongoing. The cohort study is currently divided into three study phases (phase 1: diagnosis to age 1 year; phase 2: age 1 to 3 years; and phase 3: age 3 to 6 years). Study participants have weekly telephone interviews, weekly anterior nasal swab collection and two study visits in the first year of life. They also complete follow-up study visits at 3 and 6 years of age. Data for this study are derived from questionnaires, lung function measurements, telephone interviews, nasal swab material and magnetic resonance imaging. To date, 70 infants have been recruited into the study and 56 have completed phase 1, including a baseline study visit at 6 weeks of age, weekly surveillance and a study visit at one year of age. More than 2500 data points on respiratory health and almost 2000 nasal samples have been collected. Phases 2 and 3 will commence in 2018. The dataset of the SCILD cohort combines lung function data, the collection of environmental and sociodemographic factors, documentation of respiratory symptoms, and microbiological analyses. The design not only allows tracking of the cystic fibrosis lung disease independent of clinical status, but also surveillance of early disease prior to severe clinical symptoms. This cohort profile provides details on the study design and summarizes the first published results of the SCILD cohort.

A Prospective Cohort of American Indian and Alaska Native People: Study Design, Methods, and Implementation

PubMed Central

Slattery, M. L.; Schumacher, M. C.; Lanier, A. P.; Edwards, S.; Edwards, R.; Murtaugh, M. A.; Sandidge, J.; Day, G. E.; Kaufman, D.; Kanekar, S.; Tom-Orme, L.; Henderson, J. A.

2008-01-01

In 2001, the National Cancer Institute funded three centers to test the feasibility of establishing a cohort of American Indian and Alaska Native people. Participating tribal organizations named the study EARTH (Education and Research Towards Health). This paper describes the study methods. A computerized data collection and tracking system was developed using audio computer-assisted survey methodology with touch screens. Data were collected on diet, physical activity, lifestyle and cultural practices, medical and reproductive history, and family history of heart disease, diabetes, and cancer. In addition, a small panel of medical measurements was obtained, including height, weight, waist and hip circumferences, blood pressure, and a lipid panel plus glucose. At the completion of the enrollment visit, data were used to provide immediate health feedback to study participants. During the initial funding period, the authors anticipate enrolling 16,000 American Indian and Alaska Native participants. The age distribution of the study population was similar to that reported in the 2000 US Census for the relevant populations. A component critical to the success of the EARTH Study has been the partnerships with tribal members. The study has focused on involvement of American Indian and Alaska Native communities in development and implementation and on provision of feedback to participants and communities. PMID:17586578

Blinatumomab vs historical standard therapy of adult relapsed/refractory acute lymphoblastic leukemia.

PubMed

Gökbuget, N; Kelsh, M; Chia, V; Advani, A; Bassan, R; Dombret, H; Doubek, M; Fielding, A K; Giebel, S; Haddad, V; Hoelzer, D; Holland, C; Ifrah, N; Katz, A; Maniar, T; Martinelli, G; Morgades, M; O'Brien, S; Ribera, J-M; Rowe, J M; Stein, A; Topp, M; Wadleigh, M; Kantarjian, H

2016-09-23

We compared outcomes from a single-arm study of blinatumomab in adult patients with B-precursor Ph-negative relapsed/refractory acute lymphoblastic leukemia (R/R ALL) with a historical data set from Europe and the United States. Estimates of complete remission (CR) and overall survival (OS) were weighted by the frequency distribution of prognostic factors in the blinatumomab trial. Outcomes were also compared between the trial and historical data using propensity score methods. The historical cohort included 694 patients with CR data and 1112 patients with OS data compared with 189 patients with CR and survival data in the blinatumomab trial. The weighted analysis revealed a CR rate of 24% (95% CI: 20-27%) and a median OS of 3.3 months (95% CI: 2.8-3.6) in the historical cohort compared with a CR/CRh rate of 43% (95% CI: 36-50%) and a median OS of 6.1 months (95% CI: 4.2-7.5) in the blinatumomab trial. Propensity score analysis estimated increased odds of CR/CRh (OR=2.68, 95% CI: 1.67-4.31) and improved OS (HR=0.536, 95% CI: 0.394-0.730) with blinatumomab. The analysis demonstrates the application of different study designs and statistical methods to compare novel therapies for R/R ALL with historical data.

Reducing case ascertainment costs in US population studies of Alzheimer's disease, dementia, and cognitive impairment—Part 1*

PubMed Central

Weir, David R.; Wallace, Robert B.; Langa, Kenneth M.; Plassman, Brenda L.; Wilson, Robert S.; Bennett, David A.; Duara, Ranjan; Loewenstein, David; Ganguli, Mary; Sano, Mary

2011-01-01

Establishing methods for ascertainment of dementia and cognitive impairment that are accurate and also cost effective is a challenging enterprise. Large population-based studies often using administrative data sets offer relatively inexpensive but reliable estimates of severe conditions including moderate to advanced dementia that are useful for public health planning, but they can miss less severe cognitive impairment which may be the most effective point for intervention. Clinical and epidemiological cohorts, intensively assessed, provide more sensitive detection of less severe cognitive impairment but are often costly. Here, several approaches to ascertainment are evaluated for validity, reliability, and cost. In particular, the methods of ascertainment from the Health and Retirement Study (HRS) are described briefly, along with those of the Aging, Demographics, and Memory Study (ADAMS). ADAMS, a resource-intense sub-study of the HRS, was designed to provide diagnostic accuracy among persons with more advanced dementia. A proposal to streamline future ADAMS assessments is offered. Also considered are decision tree, algorithmic, and web-based approaches to diagnosis that can reduce the expense of clinical expertise and, in some contexts, can reduce the extent of data collection. These approaches are intended for intensively assessed epidemiological cohorts. The goal is valid and reliable detection with efficient and cost-effective tools. PMID:21255747

e-Vita: design of an innovative approach to COPD disease management in primary care through eHealth application.

PubMed

Talboom-Kamp, E P W A; Verdijk, N A; Blom, C M G; Harmans, L M; Talboom, I J S H; Numans, M E; Chavannes, N H

2016-08-17

COPD is a highly complex disease to manage as patients show great variation in symptoms and limitations in daily life. In the last decade self-management support of COPD has been introduced as an effective method to improve quality and efficiency of care, and to reduce healthcare costs. Despite the urge to change the organisation of health care and the potential of eHealth to support this, large-scale implementation in daily practice remains behind, especially in the Netherlands. We designed a multilevel study, called e-Vita, to investigate different organisational implementation methods of a self-management web portal to support and empower patients with COPD in three different primary care settings. Using a parallel cohort design, the clinical effects of the web portal will be assessed using an interrupted times series (ITS) study design and measured according to changes in health status with the Clinical COPD Questionnaire (CCQ). The different implementations and net benefits of self-management through eHealth on clinical outcomes will be evaluated from human, organisational, and technical perspectives. To our knowledge this is the first study to combine different study designs that enable simultaneous investigation of clinical effects, as well as effects of different organisational implementation methods whilst controlling for confounding effects of the organisational characteristics. We hypothesize that an implementation with higher levels of personal assistance, and integrated in an existing care program will result in increased use of and satisfaction with the platform, thereby increasing health status and diminishing exacerbation and hospitalisation. NTR4098 (31-07-2013).

e-Vita: design of an innovative approach to COPD disease management in primary care through eHealth application.

PubMed

Talboom-Kamp, E P W A; Verdijk, N A; Blom, C M G; Harmans, L M; Talboom, I J S H; Numans, M E; Chavannes, N H

2016-08-16

COPD is a highly complex disease to manage as patients show great variation in symptoms and limitations in daily life. In the last decade self-management support of COPD has been introduced as an effective method to improve quality and efficiency of care, and to reduce healthcare costs. Despite the urge to change the organisation of health care and the potential of eHealth to support this, large-scale implementation in daily practice remains behind, especially in the Netherlands. We designed a multilevel study, called e-Vita, to investigate different organisational implementation methods of a self-management web portal to support and empower patients with COPD in three different primary care settings. Using a parallel cohort design, the clinical effects of the web portal will be assessed using an interrupted times series (ITS) study design and measured according to changes in health status with the Clinical COPD Questionnaire (CCQ). The different implementations and net benefits of self-management through eHealth on clinical outcomes will be evaluated from human, organisational, and technical perspectives. To our knowledge this is the first study to combine different study designs that enable simultaneous investigation of clinical effects, as well as effects of different organisational implementation methods whilst controlling for confounding effects of the organisational characteristics. We hypothesize that an implementation with higher levels of personal assistance, and integrated in an existing care program will result in increased use of and satisfaction with the platform, thereby increasing health status and diminishing exacerbation and hospitalisation. NTR4098 (31-07-2013).

The HIV-Brazil Cohort Study: Design, Methods and Participant Characteristics

PubMed Central

Grangeiro, Alexandre; Escuder, Maria Mercedes; Cassanote, Alex Jones Flores; Souza, Rosa Alencar; Kalichman, Artur O.; Veloso, Valdiléa; Ikeda, Maria Letícia Rodrigues; Barcellos, Nêmora Tregnago; Brites, Carlos; Tupinanbás, Unai; Lucena, Noaldo O.; da Silva, Carlos Lima; Lacerda, Heloisa Ramos; Grinsztejn, Beatriz; Castilho, Euclides Ayres

2014-01-01

Background The HIV-Brazil Cohort Study was established to analyze the effectiveness of combination antiretroviral therapy (cART) and the impact of this treatment on morbidity, quality of life (QOL) and mortality. The study design, patients’ profiles and characteristics of cART initiation between 2003 and 2010 were described. Methodology/Principal Findings Since 2003, the HIV-Brazil Cohort has been following HIV-infected adults receiving cART at 26 public health care facilities, using routine clinical care data and self-reported QOL questionnaires. When not otherwise available, data are obtained from national information systems. The main outcomes of interest are diseases related or unrelated to HIV; suppression of viral replication; adverse events; virological, clinical and immunological failures; changes in the cART; and mortality. For the 5,061 patients who started cART between 2003 and 2010, the median follow-up time was 4.1 years (IQR 2.2–5.9 years) with an 83.4% retention rate. Patient profiles were characterized by a predominance of men (male/female ratio 1.7∶1), with a mean age of 36.9 years (SD 9.9 years); 55.2% had been infected with HIV via heterosexual contact. The majority of patients (53.4%) initiated cART with a CD4+ T-cell count ≤200 cells/mm3. The medications most often used in the various treatment regimens were efavirenz (59.7%) and lopinavir/ritonavir (18.2%). The proportion of individuals achieving viral suppression within the first 12 months of cART use was 77.4% (95% CI 76.1–78.6). Nearly half (45.4%) of the patients presented HIV-related clinical manifestations after starting cART, and the AIDS mortality rate was 13.9 per 1,000 person-years. Conclusions/Significance Results from cART use in the daily practice of health services remain relatively unknown in low- and middle-income countries, and studies with the characteristics of the HIV-Brazil Cohort contribute to minimizing these shortcomings, given its scope and patient profile, which is similar to that of the AIDS epidemic in the country. PMID:24789106

Is volunteering a public health intervention? A systematic review and meta-analysis of the health and survival of volunteers

PubMed Central

2013-01-01

Background Volunteering has been advocated by the United Nations, and American and European governments as a way to engage people in their local communities and improve social capital, with the potential for public health benefits such as improving wellbeing and decreasing health inequalities. Furthermore, the US Corporation for National and Community Service Strategic Plan for 2011–2015 focused on increasing the impact of national service on community needs, supporting volunteers’ wellbeing, and prioritising recruitment and engagement of underrepresented populations. The aims of this review were to examine the effect of formal volunteering on volunteers’ physical and mental health and survival, and to explore the influence of volunteering type and intensity on health outcomes. Methods Experimental and cohort studies comparing the physical and mental health outcomes and mortality of a volunteering group to a non-volunteering group were identified from twelve electronic databases (Cochrane Library, Medline, Embase, PsychINFO, CINAHL, ERIC, HMIC, SSCI, ASSIA, Social Care Online, Social Policy and Practice) and citation tracking in January 2013. No language, country or date restrictions were applied. Data synthesis was based on vote counting and random effects meta-analysis of mortality risk ratios. Results Forty papers were selected: five randomised controlled trials (RCTs, seven papers); four non-RCTs; and 17 cohort studies (29 papers). Cohort studies showed volunteering had favourable effects on depression, life satisfaction, wellbeing but not on physical health. These findings were not confirmed by experimental studies. Meta-analysis of five cohort studies found volunteers to be at lower risk of mortality (risk ratio: 0.78; 95% CI: 0.66, 0.90). There was insufficient evidence to demonstrate a consistent influence of volunteering type or intensity on outcomes. Conclusion Observational evidence suggested that volunteering may benefit mental health and survival although the causal mechanisms remain unclear. Consequently, there was limited robustly designed research to guide the development of volunteering as a public health promotion intervention. Future studies should explicitly map intervention design to clear health outcomes as well as use pragmatic RCT methodology to test effects. PMID:23968220

Do shorter delays to care and mental health system renewal translate into better occupational outcome after mental disorder diagnosis in a cohort of Canadian military personnel who returned from an Afghanistan deployment?

PubMed Central

Boulos, David; Zamorski, Mark A

2015-01-01

Objective Mental disorders in military personnel result in high rates of attrition. Military organisations have strengthened their mental health systems and attempted to overcome barriers to care in order to see better outcomes. This study investigated the roles of mental health services renewal and delay to care in Canadian Armed Forces (CAF) personnel diagnosed with mental disorders. Design Administrative data were used to identify a retrospective cohort of 30 513 CAF personnel who deployed in support of the mission in Afghanistan. Study participants included 508 individuals with a mental disorder diagnosis identified from CAF medical records of a weighted, stratified random sample of 2014 individuals selected from the study cohort. Weighted Cox proportional hazards regression assessed the association of diagnosis era and delay to care with the outcome, after controlling for a broad range of potential confounders (eg, disorder severity, comorbidity). Taylor series linearisation methods and sample design weights were applied in generating descriptive and regression analysis statistics. Primary outcome The outcome was release from military service for medical reasons, assessed using administrative data for the 508 individuals with a mental disorder diagnosis. Results 17.5% (95% CI 16.0% to 19.0%) of the cohort had a mental disorder diagnosis after an Afghanistan-related deployment, of which 21.3% (95% CI 17.2% to 25.5%) had a medical release over a median follow-up of 3.5 years. Medical release risk was elevated for individuals diagnosed before 30 April 2008 relative to those with recent diagnoses (adjusted HR (aHR)=1.77 (95% CI 1.01 to 3.11)) and for individuals with a long delay to care (>21 months after return) relative to those with intermediate delays (8–21 months, aHR 2.47=(95% CI 1.28 to 4.76)). Conclusions Mental health services renewal in the CAF was associated with a better occupational outcome for those diagnosed with mental disorders. Longer delays to care were associated with a less favourable outcome. PMID:26644121

Effects of Preoperative Simulation on Minimally Invasive Hybrid Lumbar Interbody Fusion.

PubMed

Rieger, Bernhard; Jiang, Hongzhen; Reinshagen, Clemens; Molcanyi, Marek; Zivcak, Jozef; Grönemeyer, Dietrich; Bosche, Bert; Schackert, Gabriele; Ruess, Daniel

2017-10-01

The main focus of this study was to evaluate how preoperative simulation affects the surgical work flow, radiation exposure, and outcome of minimally invasive hybrid lumbar interbody fusion (MIS-HLIF). A total of 132 patients who underwent single-level MIS-HLIF were enrolled in a cohort study design. Dose area product was analyzed in addition to surgical data. Once preoperative simulation was established, 66 cases (SIM cohort) were compared with 66 patients who had previously undergone MIS-HLIF without preoperative simulation (NO-SIM cohort). Dose area product was reduced considerably in the SIM cohort (320 cGy·cm 2 NO-SIM cohort: 470 cGy·cm 2 ; P < 0.01). Surgical time was shorter for the SIM cohort (155 minutes; NO-SIM cohort, 182 minutes; P < 0.05). SIM cohort had a better outcome in Numeric Rating Scale back at 6 months follow-up compared with the NO-SIM cohort (P < 0.05). Preoperative simulation reduced radiation exposure and resulted in less back pain at the 6 months follow-up time point. Preoperative simulation provided guidance in determining the correct cage height. Outcome controls enabled the surgeon to improve the procedure and the software algorithm. Copyright © 2017 Elsevier Inc. All rights reserved.

Predictive validity of the UK clinical aptitude test in the final years of medical school: a prospective cohort study

PubMed Central

2014-01-01

Background The UK Clinical Aptitude Test (UKCAT) was designed to address issues identified with traditional methods of selection. This study aims to examine the predictive validity of the UKCAT and compare this to traditional selection methods in the senior years of medical school. This was a follow-up study of two cohorts of students from two medical schools who had previously taken part in a study examining the predictive validity of the UKCAT in first year. Methods The sample consisted of 4th and 5th Year students who commenced their studies at the University of Aberdeen or University of Dundee medical schools in 2007. Data collected were: demographics (gender and age group), UKCAT scores; Universities and Colleges Admissions Service (UCAS) form scores; admission interview scores; Year 4 and 5 degree examination scores. Pearson’s correlations were used to examine the relationships between admissions variables, examination scores, gender and age group, and to select variables for multiple linear regression analysis to predict examination scores. Results Ninety-nine and 89 students at Aberdeen medical school from Years 4 and 5 respectively, and 51 Year 4 students in Dundee, were included in the analysis. Neither UCAS form nor interview scores were statistically significant predictors of examination performance. Conversely, the UKCAT yielded statistically significant validity coefficients between .24 and .36 in four of five assessments investigated. Multiple regression analysis showed the UKCAT made a statistically significant unique contribution to variance in examination performance in the senior years. Conclusions Results suggest the UKCAT appears to predict performance better in the later years of medical school compared to earlier years and provides modest supportive evidence for the UKCAT’s role in student selection within these institutions. Further research is needed to assess the predictive validity of the UKCAT against professional and behavioural outcomes as the cohort commences working life. PMID:24762134

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.

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.

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

Leveraging electronic healthcare record standards and semantic web technologies for the identification of patient cohorts

PubMed Central

Fernández-Breis, Jesualdo Tomás; Maldonado, José Alberto; Marcos, Mar; Legaz-García, María del Carmen; Moner, David; Torres-Sospedra, Joaquín; Esteban-Gil, Angel; Martínez-Salvador, Begoña; Robles, Montserrat

2013-01-01

Background The secondary use of electronic healthcare records (EHRs) often requires the identification of patient cohorts. In this context, an important problem is the heterogeneity of clinical data sources, which can be overcome with the combined use of standardized information models, virtual health records, and semantic technologies, since each of them contributes to solving aspects related to the semantic interoperability of EHR data. Objective To develop methods allowing for a direct use of EHR data for the identification of patient cohorts leveraging current EHR standards and semantic web technologies. Materials and methods We propose to take advantage of the best features of working with EHR standards and ontologies. Our proposal is based on our previous results and experience working with both technological infrastructures. Our main principle is to perform each activity at the abstraction level with the most appropriate technology available. This means that part of the processing will be performed using archetypes (ie, data level) and the rest using ontologies (ie, knowledge level). Our approach will start working with EHR data in proprietary format, which will be first normalized and elaborated using EHR standards and then transformed into a semantic representation, which will be exploited by automated reasoning. Results We have applied our approach to protocols for colorectal cancer screening. The results comprise the archetypes, ontologies, and datasets developed for the standardization and semantic analysis of EHR data. Anonymized real data have been used and the patients have been successfully classified by the risk of developing colorectal cancer. Conclusions This work provides new insights in how archetypes and ontologies can be effectively combined for EHR-driven phenotyping. The methodological approach can be applied to other problems provided that suitable archetypes, ontologies, and classification rules can be designed. PMID:23934950

Internet-based data inclusion in a population-based European collaborative follow-up study of inflammatory bowel disease patients: Description of methods used and analysis of factors influencing response rates

PubMed Central

Wolters, Frank L; van Zeijl, Gilbert; Sijbrandij, Jildou; Wessels, Frederik; O’Morain, Colm; Limonard, Charles; Russel, Maurice G; Stockbrügger, Reinhold W

2005-01-01

AIM: To describe an Internet-based data acquisition facility for a European 10-year clinical follow-up study project of a population-based cohort of inflammatory bowel disease (IBD) patients and to investigate the influence of demographic and disease related patient characteristics on response rates. METHODS: Thirteen years ago, the European Collaborative study group of IBD (EC-IBD) initiated a population-based prospective inception cohort of 2 201 uniformly diagnosed IBD patients within 20 well-described geographical areas in 11 European countries and Israel. For the 10-year follow-up of this cohort, an electronic patient questionnaire (ePQ) and electronic physician per patient follow-up form (ePpPFU) were designed as two separate data collecting instruments and made available through an Internet-based website. Independent demographic and clinical determinants of ePQ participation were analyzed using multivariate logistic regression. RESULTS: In 958 (316 CD and 642 UC) out of a total number of 1 505 (64%) available IBD patients, originating from 13 participating centers from nine different countries, both ePQ and ePpPFU were completed. Patients older than 40 years at ePQ completion (OR: 1.53 (95%CI: 1.14-2.05)) and those with active disease during the 3 mo previous to ePQ completion (OR: 3.32 (95%CI: 1.57-7.03)) were significantly more likely to respond. CONCLUSION: An Internet-based data acquisition tool appeared successful in sustaining a unique Western-European and Israelian multi-center 10-year clinical follow-up study project in patients afflicted with IBD. PMID:16437663

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.

Do student nurses experience Imposter Phenomenon? An international comparison of Final Year Undergraduate Nursing Students readiness for registration.

PubMed

Christensen, Martin; Aubeeluck, Aimee; Fergusson, Diana; Craft, Judy; Knight, Jessica; Wirihana, Lisa; Stupple, Ed

2016-11-01

The transition shock or Imposter Phenomena sometimes associated with moving from student to Registered Nurse can lead to feelings of self-doubt and insecurity especially with the increased expectations and responsibilities that registration brings. The aim of this study was to examine the extent at which imposter phenomenon is evident in four final year nursing student cohorts in Australia, New Zealand and the UK. A survey design. The study took place at four higher education institutes - two metropolitan campuses and two regional campuses between October 2014 - February 2015 in Australia, New Zealand and the UK. A sample of 223 final year nursing students undertaking nationally accredited nursing programmes were approached. Each cohort exhibited mild to moderate feelings of Imposter Phenomena. A positive weak correlation between imposter phenomena and preparedness for practice was found. The New Zealand cohort scored higher than both the Australian and UK cohorts on both feelings of imposterism and preparedness for practice. Nursing students possess internalized feelings which suggest their performance and competence once qualified could be compromised. There is some speculation that the respective curriculums may have some bearing on preparing students for registration and beyond. It is recommended that educational programmes designed for this student cohort should be mindful of this internal conflict and potential external hostility. © 2016 John Wiley & Sons Ltd.

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.

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

Neighborhood Socioeconomic Status and Barriers to Peritoneal Dialysis: A Mixed Methods Study

PubMed Central

Perzynski, Adam T.; Austin, Peter C.; Wu, C. Fangyun; Lawless, Mary Ellen; Paterson, J. Michael; Quinn, Rob R.; Sehgal, Ashwini R.; Oliver, Matthew James

2013-01-01

Summary Background and objectives The objective of this study was to evaluate the association between neighborhood socioeconomic status and barriers to peritoneal dialysis eligibility and choice. Design, setting, participants, & measurements This study was a mixed methods parallel design study using quantitative and qualitative data from a prospective clinical database of ESRD patients. The eligibility and choice cohorts were assembled from consecutive incident chronic dialysis patients entering one of five renal programs in the province of Ontario, Canada, between January 1, 2004 and December 31, 2010. Socioeconomic status was measured as median household income and percentage of residents with at least a high school education using Statistics Canada dissemination area-level data. Multivariable models described the relationship between socioeconomic status and likelihood of peritoneal dialysis eligibility and choice. Barriers to peritoneal dialysis eligibility and choice were classified into qualitative categories using the thematic constant comparative approach. Results The peritoneal dialysis eligibility and choice cohorts had 1314 and 857 patients, respectively; 65% of patients were deemed eligible for peritoneal dialysis, and 46% of eligible patients chose peritoneal dialysis. Socioeconomic status was not a significant predictor of peritoneal dialysis eligibility or choice in this study. Qualitative analyses identified 16 barriers to peritoneal dialysis choice. Patients in lower- versus higher-income Statistics Canada dissemination areas cited built environment or space barriers to peritoneal dialysis (4.6% versus 2.7%) and family or social support barriers (8.3% versus 3.5%) more frequently. Conclusions Peritoneal dialysis eligibility and choice were not associated with socioeconomic status. However, socioeconomic status may influence specific barriers to peritoneal dialysis choice. Additional studies to determine the effect of targeting interventions to specific barriers to peritoneal dialysis choice in low socioeconomic status patients on peritoneal dialysis use are needed. PMID:23970135

Innovations in curriculum design: A multi-disciplinary approach to teaching statistics to undergraduate medical students

PubMed Central

Freeman, Jenny V; Collier, Steve; Staniforth, David; Smith, Kevin J

2008-01-01

Background Statistics is relevant to students and practitioners in medicine and health sciences and is increasingly taught as part of the medical curriculum. However, it is common for students to dislike and under-perform in statistics. We sought to address these issues by redesigning the way that statistics is taught. Methods The project brought together a statistician, clinician and educational experts to re-conceptualize the syllabus, and focused on developing different methods of delivery. New teaching materials, including videos, animations and contextualized workbooks were designed and produced, placing greater emphasis on applying statistics and interpreting data. Results Two cohorts of students were evaluated, one with old style and one with new style teaching. Both were similar with respect to age, gender and previous level of statistics. Students who were taught using the new approach could better define the key concepts of p-value and confidence interval (p < 0.001 for both). They were more likely to regard statistics as integral to medical practice (p = 0.03), and to expect to use it in their medical career (p = 0.003). There was no significant difference in the numbers who thought that statistics was essential to understand the literature (p = 0.28) and those who felt comfortable with the basics of statistics (p = 0.06). More than half the students in both cohorts felt that they were comfortable with the basics of medical statistics. Conclusion Using a variety of media, and placing emphasis on interpretation can help make teaching, learning and understanding of statistics more people-centred and relevant, resulting in better outcomes for students. PMID:18452599

Reducing selection bias in case-control studies from rare disease registries.

PubMed

Cole, J Alexander; Taylor, John S; Hangartner, Thomas N; Weinreb, Neal J; Mistry, Pramod K; Khan, Aneal

2011-09-12

In clinical research of rare diseases, where small patient numbers and disease heterogeneity limit study design options, registries are a valuable resource for demographic and outcome information. However, in contrast to prospective, randomized clinical trials, the observational design of registries is prone to introduce selection bias and negatively impact the validity of data analyses. The objective of the study was to demonstrate the utility of case-control matching and the risk-set method in order to control bias in data from a rare disease registry. Data from the International Collaborative Gaucher Group (ICGG) Gaucher Registry were used as an example. A case-control matching analysis using the risk-set method was conducted to identify two groups of patients with type 1 Gaucher disease in the ICGG Gaucher Registry: patients with avascular osteonecrosis (AVN) and those without AVN. The frequency distributions of gender, decade of birth, treatment status, and splenectomy status were presented for cases and controls before and after matching. Odds ratios (and 95% confidence intervals) were calculated for each variable before and after matching. The application of case-control matching methodology results in cohorts of cases (i.e., patients with AVN) and controls (i.e., patients without AVN) who have comparable distributions for four common parameters used in subject selection: gender, year of birth (age), treatment status, and splenectomy status. Matching resulted in odds ratios of approximately 1.00, indicating no bias. We demonstrated bias in case-control selection in subjects from a prototype rare disease registry and used case-control matching to minimize this bias. Therefore, this approach appears useful to study cohorts of heterogeneous patients in rare disease registries.

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…

Predictors of Cerebral Palsy in Very Preterm Infants: The EPIPAGE Prospective Population-Based Cohort Study

ERIC Educational Resources Information Center

Beaino, Ghada; Khoshnood, Babak; Kaminski, Monique; Pierrat, Veronique; Marret, Stephane; Matis, Jacqueline; Ledesert, Bernard; Thiriez, Gerard; Fresson, Jeanne; Roze, Jean-Christophe; Zupan-Simunek, Veronique; Arnaud, Catherine; Burguet, Antoine; Larroque, Beatrice; Breart, Gerard; Ancel, Pierre-Yves

2010-01-01

Aim: The aim of this study was to assess the independent role of cerebral lesions on ultrasound scan, and several other neonatal and obstetric factors, as potential predictors of cerebral palsy (CP) in a large population-based cohort of very preterm infants. Method: As part of EPIPAGE, a population-based prospective cohort study, perinatal data…

Social Information-Processing Skills and Aggression: A Quasi-Experimental Trial of the Making Choices and Making Choices Plus Programs

ERIC Educational Resources Information Center

Terzian, Mary A.; Li, Jilan; Fraser, Mark W.; Day, Steven H.; Rose, Roderick A.

2015-01-01

This article describes the findings from an efficacy trial of a school-based, universal prevention program designed to reduce aggressive behavior of by strengthening emotion regulation and social information-processing (SIP) skills. Three cohorts of third graders (N = 479) participated in this study. The first cohort participated in the Making…

Longitudinal Investigation of Source Memory Reveals Different Developmental Trajectories for Item Memory and Binding

ERIC Educational Resources Information Center

Riggins, Tracy

2014-01-01

The present study used a cohort-sequential design to examine developmental changes in children's ability to bind items in memory during early and middle childhood. Three cohorts of children (aged 4, 6, or 8 years) were followed longitudinally for 3 years. Each year, children completed a source memory paradigm assessing memory for items and…

Learning Alone, Together: Closed-Cohort Structure in an Online Journalism and Mass Communication Graduate Program

ERIC Educational Resources Information Center

Blankenship, Justin C.; Gibson, Rhonda

2016-01-01

In a closed-cohort educational program design, students enter a program together, take the same courses together, and, ideally, graduate together. In an effort to increase interaction and communication among students, it has been utilized more and more for online graduate programs. This article surveyed students in one of the few closed-cohort…

78 FR 18350 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... Supply Company in Fort Wayne, Indiana, as an addition to the Special Exposure Cohort (SEC) under the... Employees who worked for Joslyn Manufacturing and Supply Company at the covered facility in Fort Wayne, Indiana, from March 1, 1943, through December 31, 1947, for a number of work days aggregating at least 250...

Low Birth Weight and Cognitive Outcomes: Evidence for a Gradient Relationship in an Urban, Poor, African American Birth Cohort

ERIC Educational Resources Information Center

Dombrowski, Stefan C.; Noonan, Kelly; Martin, Roy P.

2007-01-01

This study is one of the first to investigate the relationship between low birth weight and cognitive outcomes in an urban, poor, prospectively designed African-American birth cohort. Multivariate analyses of the Pathways to Adulthood study, a subset of the Johns Hopkins Collaborative Perinatal study, compared low birth weight African-American…

Developmental Personality Types from Childhood to Adolescence: Associations with Parenting and Adjustment

ERIC Educational Resources Information Center

de Haan, Amaranta D.; Dekovic, Maja; van den Akker, Alithe L.; Stoltz, Sabine E. M. J.; Prinzie, Peter

2013-01-01

This study examined whether changes in children's self-reported Big Five dimensions are represented by (developmental) personality types, using a cohort-sequential design with three measurement occasions across 5 years (four cohorts, 9-12 years at T1; N = 523). Correlates of, and gender differences in, type membership were examined. Latent…

77 FR 58382 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health (NIOSH), Centers for... December 31, 1961, for a number of work days aggregating at least 250 work days, occurring either solely... Institute for Occupational Safety and Health. [FR Doc. 2012-23272 Filed 9-19-12; 8:45 am] BILLING CODE 4163...

77 FR 38835 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... Addition to the Special Exposure Cohort AGENCY: National Institute for Occupational Safety and Health... aggregating at least 250 work days, occurring either solely under this employment, or in combination with work... Occupational Safety and Health. [FR Doc. 2012-15968 Filed 6-28-12; 8:45 am] BILLING CODE 4163-19-P ...