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

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.

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

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.

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

PubMed

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

2017-06-06

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

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%.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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

PubMed Central

2013-01-01

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

Developing and Refining the Taiwan Birth Cohort Study (TBCS): Five Years of Experience

ERIC Educational Resources Information Center

Lung, For-Wey; Chiang, Tung-Liang; Lin, Shio-Jean; Shu, Bih-Ching; Lee, Meng-Chih

2011-01-01

The Taiwan Birth Cohort Study (TBCS) is the first nationwide birth cohort database in Asia designed to establish national norms of children's development. Several challenges during database development and data analysis were identified. Challenges include sampling methods, instrument development and statistical approach to missing data. The…

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

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…

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.

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

A regularized variable selection procedure in additive hazards model with stratified case-cohort design.

PubMed

Ni, Ai; Cai, Jianwen

2018-07-01

Case-cohort designs are commonly used in large epidemiological studies to reduce the cost associated with covariate measurement. In many such studies the number of covariates is very large. An efficient variable selection method is needed for case-cohort studies where the covariates are only observed in a subset of the sample. Current literature on this topic has been focused on the proportional hazards model. However, in many studies the additive hazards model is preferred over the proportional hazards model either because the proportional hazards assumption is violated or the additive hazards model provides more relevent information to the research question. Motivated by one such study, the Atherosclerosis Risk in Communities (ARIC) study, we investigate the properties of a regularized variable selection procedure in stratified case-cohort design under an additive hazards model with a diverging number of parameters. We establish the consistency and asymptotic normality of the penalized estimator and prove its oracle property. Simulation studies are conducted to assess the finite sample performance of the proposed method with a modified cross-validation tuning parameter selection methods. We apply the variable selection procedure to the ARIC study to demonstrate its practical use.

[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.

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.

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.

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.

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

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.

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

PubMed

Rivera, C L; Lumley, T

2016-08-15

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

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.

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

PubMed

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

2012-04-02

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

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

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…

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.

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.

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.

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.

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...

Piecewise exponential survival times and analysis of case-cohort data.

PubMed

Li, Yan; Gail, Mitchell H; Preston, Dale L; Graubard, Barry I; Lubin, Jay H

2012-06-15

Case-cohort designs select a random sample of a cohort to be used as control with cases arising from the follow-up of the cohort. Analyses of case-cohort studies with time-varying exposures that use Cox partial likelihood methods can be computer intensive. We propose a piecewise-exponential approach where Poisson regression model parameters are estimated from a pseudolikelihood and the corresponding variances are derived by applying Taylor linearization methods that are used in survey research. The proposed approach is evaluated using Monte Carlo simulations. An illustration is provided using data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of male smokers in Finland, where a case-cohort study of serum glucose level and pancreatic cancer was analyzed. Copyright © 2012 John Wiley & Sons, Ltd.

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.

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.

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.

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

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.

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

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

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.

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

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 ...

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.

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

ERIC Educational Resources Information Center

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

2010-01-01

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

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

ERIC Educational Resources Information Center

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

2012-01-01

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

Review of the literature on benzene exposure and leukemia subtypes.

PubMed

Schnatter, A Robert; Rosamilia, Kim; Wojcik, Nancy C

2005-05-30

The epidemiologic literature on benzene exposure and leukemia in the MEDLINE and TOXNET databases was examined through October 2004 using the keywords "benzene", "leukemia" and "adverse health effects". This search was complemented by reviewing the reference lists from extant literature reviews and criteria documents on benzene. Published studies were characterized according to the type of industry studied and design, exposure assessment, disease classification, and control for confounding variables. Study design consisted of either cohort studies or case-control studies, which were further categorized into population-based and nested case-control studies. Disease classification considered the source of diagnostic information, whether there was clinical confirmation from medical records or histopathological, morphological and/or cytogenetic reviews, and as to whether the International Classification of Diseases (ICD) or the French-American-British (FAB) schemes were used (no studies used the Revised European-American Lymphoma (REAL) classification scheme). Nine cohort and 13 case-control studies met inclusion criteria for this review. High and significant acute myeloid leukemia risks with positive dose response relationships were identified across study designs, particularly in the "well-conducted" cohort studies and especially in more highly exposed workers in rubber, shoe, and paint industries. Risks for chronic lymphocytic leukemia (CLL) tended to show elevations in nested case-control studies, with possible dose response relationships in at least two of the three studies. However, cohort studies on CLL show no such risks. Data for chronic myeloid leukemia and acute lymphocytic leukemia are sparse and inconclusive.

"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.

A comparison of the results of prospective and retrospective cohort studies in the field of digestive surgery.

PubMed

Ukai, Tomohiko; Shikata, Satoru; Nakayama, Takeo; Takemura, Yousuke C

2017-07-01

We compared the results of prospective and retrospective cohort studies in the field of digestive surgery to clarify whether the results of prospective cohort studies were more similar to those of randomized controlled trials (RCTs). We conducted a secondary analysis of the results to compare the results of RCTs with those of cohort studies in meta-analyses of 18 digestive surgical topics. The data from the prospective and retrospective cohort studies were combined. The summary estimates of each design were compared with those of RCTs. We used the Z score to investigate discrepancies. Twenty-nine outcomes of 11 topics were investigated in 289 cohort studies (prospective, n = 69; retrospective, n = 220). These were compared with the outcomes of 123 RCTs. In comparison to retrospective studies, the summary estimates of the prospective cohort studies were more similar to those of the RCTs [19/29 (prospective) vs. 10/29 (retrospective), P = 0.035). Five of the 29 outcomes of prospective studies and 6 of 29 outcomes of retrospective studies (P = 0.99) showed significant discrepancies in comparison to RCTs. In the digestive surgical field, the results of prospective cohort studies tended to be more similar to those of RCTs than retrospective studies; however, there were no significant discrepancies between the two types of cohort study.

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

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.

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

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...

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

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

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.

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.

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…

Global Quality of Life (QOL), Health and Ability Are Primarily Determined by Our Consciousness: Research Findings from Denmark 1991-2004

ERIC Educational Resources Information Center

Ventegodt, Soren; Flensborg-Madsen, Trine; Andersen, Niels Jorgen; Nielsen, Michael; Mohammed, Morad; Merrick, Joav

2005-01-01

Objective: To explain the global quality of life (QOL) from 2000 indicators representing all aspects of life. Design and setting: Two cross sectional population studies, one prospective cohort study and one retrospective cohort study. Participants: (1) Representative sample of 2500 Danes (18-88 years), (2) 7222 members of the Copenhagen Perinatal…

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.

The healthy men study: design and recruitment considerations for environmental epidemiologic studies in male reproductive health

EPA Science Inventory

Study Objective: To describe study conduct and response and participant characteristics. Design: Prospective cohort study. Setting: Participants were male partners of women enrolled in a community-based study of drinking water disinfection by-products and pregnancy healt...

Preschool: First Findings from the Preschool Follow-Up of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B). First Look. NCES 2008-025

ERIC Educational Resources Information Center

Chernoff, Jodi Jacobson; Flanagan, Kristin Denton; McPhee, Cameron; Park, Jennifer

2007-01-01

The Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) is designed to provide detailed information on children's development, health, and early learning experiences in the years leading up to entry into school. The ECLS-B is the first nationally representative study within the United States to directly assess children's early mental and…

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.

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…

Quality of Reporting and Study Design of CKD Cohort Studies Assessing Mortality in the Elderly Before and After STROBE: A Systematic Review.

PubMed

Rao, Anirudh; Brück, Katharina; Methven, Shona; Evans, Rebecca; Stel, Vianda S; Jager, Kitty J; Hooft, Lotty; Ben-Shlomo, Yoav; Caskey, Fergus

2016-01-01

The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement was published in October 2007 to improve quality of reporting of observational studies. The aim of this review was to assess the impact of the STROBE statement on observational study reporting and study design quality in the nephrology literature. Systematic literature review. European and North American, Pre-dialysis Chronic Kidney Disease (CKD) cohort studies. Studies assessing the association between CKD and mortality in the elderly (>65 years) published from 1st January 2002 to 31st December 2013 were included, following systematic searching of MEDLINE & EMBASE. Time period before and after the publication of the STROBE statement. Quality of study reporting using the STROBE statement and quality of study design using the Newcastle Ottawa Scale (NOS), Scottish Intercollegiate Guidelines Network (SIGN) and Critical Appraisal Skills Programme (CASP) tools. 37 papers (11 Pre & 26 Post STROBE) were identified from 3621 potential articles. Only four of the 22 STROBE items and their sub-criteria (objectives reporting, choice of quantitative groups and description of and carrying out sensitivity analysis) showed improvements, with the majority of items showing little change between the period before and after publication of the STROBE statement. Pre- and post-period analysis revealed a Manuscript STROBE score increase (median score 77.8% (Inter-quartile range [IQR], 64.7-82.0) vs 83% (IQR, 78.4-84.9, p = 0.05). There was no change in quality of study design with identical median scores in the two periods for NOS (Manuscript NOS score 88.9), SIGN (Manuscript SIGN score 83.3) and CASP (Manuscript CASP score 91.7) tools. Only 37 Studies from Europe and North America were included from one medical specialty. Assessment of study design largely reliant on good reporting. This study highlights continuing deficiencies in the reporting of STROBE items and their sub-criteria in cohort studies in nephrology. There was weak evidence of improvement in the overall reporting quality, with no improvement in methodological quality of CKD cohort studies between the period before and after publication of the STROBE statement.

"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

Cohort profile: cerebral palsy in the Norwegian and Danish birth cohorts (MOBAND-CP)

PubMed Central

Tollånes, Mette C; Strandberg-Larsen, Katrine; Forthun, Ingeborg; Petersen, Tanja Gram; Moster, Dag; Andersen, Anne-Marie Nybo; Stoltenberg, Camilla; Olsen, Jørn; Wilcox, Allen J

2016-01-01

Purpose The purpose of MOthers and BAbies in Norway and Denmark cerebral palsy (MOBAND-CP) was to study CP aetiology in a prospective design. Participants MOBAND-CP is a cohort of more than 210 000 children, created as a collaboration between the world's two largest pregnancy cohorts—the Norwegian Mother and Child Cohort study (MoBa) and the Danish National Birth Cohort. MOBAND-CP includes maternal interview/questionnaire data collected during pregnancy and follow-up, plus linked information from national health registries. Findings to date Initial harmonisation of data from the 2 cohorts has created 140 variables for children and their mothers. In the MOBAND-CP cohort, 438 children with CP have been identified through record linkage with validated national registries, providing by far the largest such sample with prospectively collected detailed pregnancy data. Several studies investigating various hypotheses regarding CP aetiology are currently on-going. Future plans Additional data can be harmonised as necessary to meet requirements of new projects. Biological specimens collected during pregnancy and at delivery are potentially available for assay, as are results from assays conducted on these specimens for other projects. The study size allows consideration of CP subtypes, which is rare in aetiological studies of CP. In addition, MOBAND-CP provides a platform within the context of a merged birth cohort of exceptional size that could, after appropriate permissions have been sought, be used for cohort and case-cohort studies of other relatively rare health conditions of infants and children. PMID:27591025

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

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

Quality of Reporting and Study Design of CKD Cohort Studies Assessing Mortality in the Elderly Before and After STROBE: A Systematic Review

PubMed Central

Brück, Katharina; Methven, Shona; Evans, Rebecca; Stel, Vianda S.; Jager, Kitty J.; Hooft, Lotty; Ben-Shlomo, Yoav; Caskey, Fergus

2016-01-01

Background The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement was published in October 2007 to improve quality of reporting of observational studies. The aim of this review was to assess the impact of the STROBE statement on observational study reporting and study design quality in the nephrology literature. Study Design Systematic literature review. Setting & Population European and North American, Pre-dialysis Chronic Kidney Disease (CKD) cohort studies. Selection Criteria for Studies Studies assessing the association between CKD and mortality in the elderly (>65 years) published from 1st January 2002 to 31st December 2013 were included, following systematic searching of MEDLINE & EMBASE. Predictor Time period before and after the publication of the STROBE statement. Outcome Quality of study reporting using the STROBE statement and quality of study design using the Newcastle Ottawa Scale (NOS), Scottish Intercollegiate Guidelines Network (SIGN) and Critical Appraisal Skills Programme (CASP) tools. Results 37 papers (11 Pre & 26 Post STROBE) were identified from 3621 potential articles. Only four of the 22 STROBE items and their sub-criteria (objectives reporting, choice of quantitative groups and description of and carrying out sensitivity analysis) showed improvements, with the majority of items showing little change between the period before and after publication of the STROBE statement. Pre- and post-period analysis revealed a Manuscript STROBE score increase (median score 77.8% (Inter-quartile range [IQR], 64.7–82.0) vs 83% (IQR, 78.4–84.9, p = 0.05). There was no change in quality of study design with identical median scores in the two periods for NOS (Manuscript NOS score 88.9), SIGN (Manuscript SIGN score 83.3) and CASP (Manuscript CASP score 91.7) tools. Limitations Only 37 Studies from Europe and North America were included from one medical specialty. Assessment of study design largely reliant on good reporting. Conclusions This study highlights continuing deficiencies in the reporting of STROBE items and their sub-criteria in cohort studies in nephrology. There was weak evidence of improvement in the overall reporting quality, with no improvement in methodological quality of CKD cohort studies between the period before and after publication of the STROBE statement. PMID:27168187

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.

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.

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

DEMOGRAPHIC CHARACTERISTICS OF THE NHEXAS-ARIZONA BORDER STUDY POPULATION

EPA Science Inventory

The NHEXAS-Arizona Border Study employed a population based probability design to recruit a representative cohort residing within 40 Km of the US-Mexico Border in Arizona. As an extension of the NHEXAS Arizona statewide survey, the border study was designed to determine the dis...

Understanding the Declining Canadian Homicide Rate: A Test of Holinger's Relative Cohort Size Hypothesis

ERIC Educational Resources Information Center

Leenaars, Antoon A.; Lester, David

2004-01-01

Homicide rates in Canada have shown a decline since 1975, but there has been little empirical study of this trend. P. Holinger (1987) predicted and confirmed that the size of the cohort aged 15-24 in the United States population was associated with the rise and fall of the homicide rate in that country. This study was designed to test this…

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.

Aragon workers' health study - design and cohort description

USDA-ARS?s Scientific Manuscript database

Spain, a Mediterranean country with relatively low rates of coronary heart disease, has a high prevalence of traditional cardiovascular risk factors and is experiencing a severe epidemic of overweight/obesity. We designed the Aragon Workers' Health Study (AWHS) to characterize the factors associated...

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…

Crohn's disease and ulcerative colitis are associated with elevated standardized mortality ratios: a meta-analysis.

PubMed

Bewtra, Meenakshi; Kaiser, Lisa M; TenHave, Tom; Lewis, James D

2013-03-01

Evidence regarding all-cause and cause-specific mortality in inflammatory bowel disease (IBD) is conflicting, and debate exists over appropriate study design to examine these important outcomes. We conducted a comprehensive meta-analysis of all-cause and cause-specific mortality in both Crohn's disease (CD) and ulcerative colitis (UC), and additionally examined various effects of study design on this outcome. A systematic search of PubMed and EMBASE was conducted to identify studies examining mortality rates relative to the general population. Pooled summary standardized mortality ratios (SMR) were calculated using random effect models. Overall, 35 original articles fulfilled the inclusion and exclusion criteria, reporting all-cause mortality SMRs varying from 0.44 to 7.14 for UC and 0.71 to 3.20 for CD. The all-cause mortality summary SMR for inception cohort and population cohort UC studies was 1.19 (95% confidence interval, 1.06-1.35). The all-cause mortality summary SMR for inception cohort and population cohort CD studies was 1.38 (95% confidence interval, 1.23-1.55). Mortality from colorectal cancer, pulmonary disease, and nonalcoholic liver disease was increased, whereas mortality from cardiovascular disease was decreased. Patients with UC and CD have higher rates of death from all causes, colorectal-cancer, pulmonary disease, and nonalcoholic liver disease.

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

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.

Evaluation of statistical designs in phase I expansion cohorts: the Dana-Farber/Harvard Cancer Center experience.

PubMed

Dahlberg, Suzanne E; Shapiro, Geoffrey I; Clark, Jeffrey W; Johnson, Bruce E

2014-07-01

Phase I trials have traditionally been designed to assess toxicity and establish phase II doses with dose-finding studies and expansion cohorts but are frequently exceeding the traditional sample size to further assess endpoints in specific patient subsets. The scientific objectives of phase I expansion cohorts and their evolving role in the current era of targeted therapies have yet to be systematically examined. Adult therapeutic phase I trials opened within Dana-Farber/Harvard Cancer Center (DF/HCC) from 1988 to 2012 were identified for sample size details. Statistical designs and study objectives of those submitted in 2011 were reviewed for expansion cohort details. Five hundred twenty-two adult therapeutic phase I trials were identified during the 25 years. The average sample size of a phase I study has increased from 33.8 patients to 73.1 patients over that time. The proportion of trials with planned enrollment of 50 or fewer patients dropped from 93.0% during the time period 1988 to 1992 to 46.0% between 2008 and 2012; at the same time, the proportion of trials enrolling 51 to 100 patients and more than 100 patients increased from 5.3% and 1.8%, respectively, to 40.5% and 13.5% (χ(2) test, two-sided P < .001). Sixteen of the 60 trials (26.7%) in 2011 enrolled patients to three or more sub-cohorts in the expansion phase. Sixty percent of studies provided no statistical justification of the sample size, although 91.7% of trials stated response as an objective. Our data suggest that phase I studies have dramatically changed in size and scientific scope within the last decade. Additional studies addressing the implications of this trend on research processes, ethical concerns, and resource burden are needed. © The Author 2014. Published by Oxford University Press. All rights reserved.

Cohort profile: cerebral palsy in the Norwegian and Danish birth cohorts (MOBAND-CP).

PubMed

Tollånes, Mette C; Strandberg-Larsen, Katrine; Forthun, Ingeborg; Petersen, Tanja Gram; Moster, Dag; Andersen, Anne-Marie Nybo; Stoltenberg, Camilla; Olsen, Jørn; Wilcox, Allen J

2016-09-02

The purpose of MOthers and BAbies in Norway and Denmark cerebral palsy (MOBAND-CP) was to study CP aetiology in a prospective design. MOBAND-CP is a cohort of more than 210 000 children, created as a collaboration between the world's two largest pregnancy cohorts-the Norwegian Mother and Child Cohort study (MoBa) and the Danish National Birth Cohort. MOBAND-CP includes maternal interview/questionnaire data collected during pregnancy and follow-up, plus linked information from national health registries. Initial harmonisation of data from the 2 cohorts has created 140 variables for children and their mothers. In the MOBAND-CP cohort, 438 children with CP have been identified through record linkage with validated national registries, providing by far the largest such sample with prospectively collected detailed pregnancy data. Several studies investigating various hypotheses regarding CP aetiology are currently on-going. Additional data can be harmonised as necessary to meet requirements of new projects. Biological specimens collected during pregnancy and at delivery are potentially available for assay, as are results from assays conducted on these specimens for other projects. The study size allows consideration of CP subtypes, which is rare in aetiological studies of CP. In addition, MOBAND-CP provides a platform within the context of a merged birth cohort of exceptional size that could, after appropriate permissions have been sought, be used for cohort and case-cohort studies of other relatively rare health conditions of infants and children. 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/

Factors Associated with Participation and Attrition in a Longitudinal Study of Bacterial Vaginosis in Australian Women Who Have Sex with Women

PubMed Central

Forcey, Dana S.; Walker, Sandra M.; Vodstrcil, Lenka A.; Fairley, Christopher K.; Bilardi, Jade E.; Law, Matthew; Hocking, Jane S.; Fethers, Katherine A.; Petersen, Susan; Bellhouse, Clare; Chen, Marcus Y.; Bradshaw, Catriona S.

2014-01-01

Objective A number of social and sexual risk factors for bacterial vaginosis (BV) have been described. It is important to understand whether these factors are associated with non-participation or attrition of participants from longitudinal studies in order to examine potential for recruitment or attrition bias. We describe factors associated with participation and attrition in a 24-month prospective cohort study, investigating incident BV among Australian women who have sex with women. Study Design and Setting Participants negative for prevalent BV were offered enrolment in a longitudinal cohort study. Participants self-collected vaginal samples and completed questionnaires 3-monthly to endpoint (BV-positive/BV-negative by 24 months). Factors associated with participation in the cohort study were examined by logistic regression and factors associated with attrition from the cohort were examined by Cox regression. Results The cross-sectional study recruited 457 women. 334 BV-negative women were eligible for the cohort and 298 (89%, 95%CI 85, 92) enrolled. Lower educational levels (aOR 2.72, 95%CI 1.09, 6.83), smoking (aOR 2.44, 95%CI 1.13, 5.27), past BV symptoms (aOR 3.42, 95%CI 1.16, 10.10) and prior genital warts (aOR 2.71, 95%CI 1.14, 6.46) were associated with non-participation; a partner co-enrolling increased participation (aOR 3.73, 95%CI 1.43, 9.70). 248 participants (83%, 95%CI 78, 87) were retained to study endpoint (BV-negative at 24 months or BV-positive at any stage). Attrition was associated being <30 yrs (aHR 2.15, 95%CI 1.13, 4.10) and a male partner at enrolment (aHR 6.12, 95%CI 1.99, 18.82). Conclusion We achieved high participation and retention levels in a prospective cohort study and report factors influencing participation and retention of participants over a 24-month study period, which will assist in the design and implementation of future cohort studies in sexual health and disease. PMID:25412421

Active cigarette smoking and the risk of breast cancer: a cohort study.

PubMed

Catsburg, Chelsea; Kirsh, Victoria A; Soskolne, Colin L; Kreiger, Nancy; Rohan, Thomas E

2014-08-01

Tobacco use has been implicated in the etiology of a large number of cancers, and there exists substantial biological plausibility that it could also be involved in breast carcinogenesis. Despite this, epidemiological evidence to date is inconsistent. The aim of this study was to investigate the role of active smoking and the risk of incident, invasive breast cancer using a prospective cohort of women from the Canadian Study of Diet, Lifestyle and Health. Using a case-cohort design, an age-stratified subcohort of 3314 women was created from 39,532 female participants who returned completed self-administered lifestyle and dietary questionnaires at baseline. A total of 1096 breast cancer cases were identified in the entire cohort (including 141 cases from the subcohort) by linkage to the Canadian Cancer Registry. Cox regression models were used to estimate hazard ratios for the association between the different smoking exposures and the risk of breast cancer, using a modification for the case-cohort design. After carefully considering early-life exposures and potential confounders, we found no association between any smoking exposure and risk of breast cancer in this study (Hazard ratio=1.00, 95% confidence interval=0.87-1.17 for ever vs never smokers). Although these results cannot rule out an association between smoking and breast cancer, they do agree with the current literature suggesting that, if an association does exist, it is relatively weak. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pregnancy as a Window to Future Cardiovascular Health: Design and Implementation of the nuMoM2b Heart Health Study

PubMed Central

Haas, David M; Ehrenthal, Deborah B; Koch, Matthew A; Catov, Janet M; Barnes, Shannon E; Facco, Francesca; Parker, Corette B; Mercer, Brian M; Bairey-Merz, C Noel; Silver, Robert M; Wapner, Ronald J; Simhan, Hyagriv N; Hoffman, Matthew K; Grobman, William A; Greenland, Philip; Wing, Deborah A; Saade, George R; Parry, Samuel; Zee, Phyllis C; Reddy, Uma M; Pemberton, Victoria L; Burwen, Dale R

2016-01-01

Abstract The National Institute of Child Health and Human Development's Nulliparous Pregnancy Outcomes Study-Monitoring Mothers-to-Be (nuMoM2b) Heart Health Study (HHS) was designed to investigate the relationships between adverse pregnancy outcomes and modifiable risk factors for cardiovascular disease. The ongoing nuMoM2b-HHS, which started in 2013, is a prospective follow-up of the nuMoM2b cohort, which included 10,038 women recruited between 2010 and 2013 from 8 centers across the United States who were initially observed over the course of their first pregnancies. In this report, we detail the design and study procedures of the nuMoM2b-HHS. Women in the pregnancy cohort who consented to be contacted for participation in future studies were approached at 6-month intervals to ascertain health information and to maintain ongoing contact. Two to 5 years after completion of the pregnancy documented in the nuMoM2b, women in the nuMoM2b-HHS were invited to an in-person study visit. During this visit, they completed psychosocial and medical history questionnaires and had clinical measurements and biological specimens obtained. A subcohort of participants who had objective assessments of sleep-disordered breathing during pregnancy were asked to repeat this investigation. This unique prospective observational study includes a large, geographically and ethnically diverse cohort, rich depth of phenotypic information about adverse pregnancy outcomes, and clinical data and biospecimens from early in the index pregnancy onward. Data obtained from this cohort will provide mechanistic and clinical insights into how data on a first pregnancy can provide information about the potential development of subsequent risk factors for cardiovascular disease. PMID:26825925

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

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…

Design and implementation of observational studies to measure disease burden with a focus on stroke.

PubMed

Howard, George; Howard, Virginia J

2018-02-01

Observational epidemiological studies have the dual goals of measuring disease burden and assessing the association between exposures and outcomes. This report focuses on the first of these goals and provides an overview of design considerations of commonly used approaches, specifically community surveillance studies, cross-sectional studies, and longitudinal cohort studies. Each of these designs has strengths and weaknesses, with no study design being superior in all cases. Rather, these designs are complementary to achieve a better understanding of the burden of stroke.

The International Childhood Cardiovascular Cohort (i3C) consortium outcomes study of childhood cardiovascular risk factors and adult cardiovascular morbidity and mortality: Design and recruitment.

PubMed

Sinaiko, Alan R; Jacobs, David R; Woo, Jessica G; Bazzano, Lydia; Burns, Trudy; Hu, Tian; Juonala, Markus; Prineas, Ronald; Raitakari, Olli; Steinberger, Julia; Urbina, Elaine; Venn, Alison; Jaquish, Cashell; Dwyer, Terry

2018-04-22

Although it is widely thought that childhood levels of cardiovascular (CV) risk factors are related to adult CV disease, longitudinal data directly linking the two are lacking. This paper describes the design and organization of the International Childhood Cardiovascular Cohort Consortium Outcomes Study (i3C Outcomes), the first longitudinal cohort study designed to locate adults with detailed, repeated, childhood biological, physical, and socioeconomic measurements and a harmonized database. I3C Outcomes uses a Heart Health Survey (HHS) to obtain information on adult CV endpoints, using mail, email, telephone, and clinic visits in the United States (U.S.) and Australia and a national health database in Finland. Microsoft Access, REsearch Data Capture (REDCap) (U.S.), LimeSurvey (Australia), and Medidata™ Rave data systems are used to collect, transfer and organize data. Self-reported CV events are adjudicated via hospital and doctor-released medical records. After the first two study years, participants (N = 10,968) were more likely to be female (56% vs. 48%), non-Hispanic white (90% vs. 80%), and older (10.4 ± 3.8 years vs. 9.4 ± 3.3 years) at their initial childhood study visit than the currently non-recruited cohort members. Over 48% of cohort members seen during both adulthood and childhood have been found and recruited, to date, vs. 5% of those not seen since childhood. Self-reported prevalences were 0.7% Type 1 Diabetes, 7.5% Type 2 Diabetes, 33% hypertension, and 12.8% CV event. 32% of CV events were judged to be true. I3C Outcomes is uniquely able to establish evidence-based guidelines for child health care and to clarify relations to adult CV disease. Copyright © 2018 Elsevier Inc. All rights reserved.

Students' perceptions of vertical and horizontal integration in a discipline-based dental school.

PubMed

Postma, T C; White, J G

2017-05-01

Integration is a key concern in discipline-based undergraduate dental curricula. Therefore, this study compared feedback on integration from students who participated in different instructional designs in a Comprehensive Patient Care course. The study was conducted at the University of Pretoria (2009-2011). Third-year cohorts (Cohorts A, B and C) participated in pre-clinical case-based learning, whilst fourth-year cohorts (Cohorts D and E) received didactic teaching in Comprehensive Patient Care. Cohorts A, D and E practised clinical Comprehensive Patient Care in a discipline-based clinic. Cohort B conducted their Comprehensive Patient Care patient examinations in a dedicated facility supervised by dedicated faculty responsible to teach integration. Students had to indicate on visual analogue scales whether the way they were taught at the school helped them to integrate knowledge from the same (horizontal integration) and preceding (vertical integration) year of study. The end-points of the scales were defined as 'definitely' and 'not at all'. Analysis of variance (ANOVA) was employed to measure the differences between cohorts according to the year of study. Third-year case-based learning cohorts rated the horizontal integration close to 80/100 and vertical integration ranging from 64 to 71/100. In year four, Cohort B rated vertical and horizontal integration 9-15% higher (ANOVA, P < 0.05) than Cohorts A and D. In year five, Cohort A rated vertical and horizontal integration 11-18% higher (ANOVA, P < 0.05) than Cohorts D and E. Pre-clinical case-based learning and Comprehensive Patient Care supervised by dedicated faculty were associated with more favourable perceptions about integration in the discipline-based undergraduate dental curriculum. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Maternal SSRI discontinuation, use, psychiatric disorder and the risk of autism in children: a meta-analysis of cohort studies.

PubMed

Kaplan, Yusuf Cem; Keskin-Arslan, Elif; Acar, Selin; Sozmen, Kaan

2017-12-01

We undertook an exclusive meta-analysis of cohort studies investigating the possible link between prenatal selective serotonin reuptake inhibitor (SSRI) exposure and autism spectrum disorders (ASD) in children to further investigate our previous suggestion of confounding by indication. The point estimates regarding the following cohorts were extracted and pooled: (1) pregnant women who discontinued SSRI until 3 months before pregnancy; (2) pregnant women who were exposed to SSRI during pregnancy; and (3) pregnant women with maternal psychiatric disorder but no exposure to SSRI during pregnancy. Although the pooled point estimate of the first cohort showed a trend for increase, it did not reach significance. The pooled point estimates of the latter cohorts showed a significant association with ASD which strengthens our previous suggestion of confounding by indication. Future studies should be adequately designed to differentiate whether the previously suggested association is a result of maternal psychiatric disorder or SSRI exposure or both. © 2017 The British Pharmacological Society.

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...

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…

Estimating the Occurrence of Child Maltreatment and Risk-Factor Effects: Benefits of a Mixed-Design Strategy in Epidemiologic Research.

ERIC Educational Resources Information Center

Bertolli, Jeanne; And Others

1995-01-01

This article discusses methodologic limitations of four observational study designs (ecologic, case-control, cross-sectional, and cohort) that dominate the child abuse and neglect literature and identifies key features of an "ideal" study of child maltreatment. It proposes a new mixed-design strategy, which improves ability to identify child…

Assessing Health Professional Students' Cultural Competence Using a Global Perspective.

PubMed

Jones, Sophia; Pinto-Zipp, Genevieve

2017-01-01

The United States has become a diverse society, and healthcare professionals must view culture from a global perspective. The purpose of this study was to determine cultural competence levels of entering and exiting health science students within and across differing professional programs using the Global Worldview Cultural Competence Survey (GWCCS). 196 students participated in the study: 146 were entering students and 59 were exiting students. From the 146 entering students, 138 surveys were usable in the data analysis, and 58 of the 59 exiting were usable. Two separate cohorts of health professional students completed the GWCCS. Cohort 1 completed the GWCCS during the first 2 weeks of their academic program, and Cohort 2 completed the GWCCS in their final-year post-clinical experience. A significant difference in GWCCS total score was observed between entering and exiting students in health sciences, with the exiting students being more culturally competent. Although this study did not utilize a longitudinal study design, the findings demonstrate that the exiting cohort of health science students was more culturally competent than the entering cohort of health science students as determined by the GWCCS. However, neither cohort of students reached the level of proficiency.

[Quality standards for epidemiologic cohort studies : An evaluated catalogue of requirements for the conduct and preparation of cohort studies].

PubMed

Schmidt, Carsten Oliver; Krabbe, Christine E M; Schössow, Janka; Berger, Klaus; Enzenbach, Cornelia; Kamtsiuris, Panagiotis; Schöne, Gina; Houben, Robin; Meisinger, Christa; Bamberg, Fabian; Hendel, Thomas; Selder, Sonja; Nonnemacher, Michael; Moebus, Susanne; Stausberg, Jürgen

2018-01-01

Cohort studies are a longitudinal observational study type. They are firmly established within epidemiology to assess the course of diseases and risk factors. Yet, standards to describe and evaluate quality characteristics of cohort studies need further development. Within the TMF ("Technologie- und Methodenplattform für die vernetzte medizinische Forschung e. V.") project "Quality management standards in cohort studies", a catalogue of requirements was compiled and evaluated, focusing on the preparation and conduct of epidemiologic cohort studies. The catalogue of requirements was established based on a consensus process between representatives of seven German epidemiologic cohort studies. For this purpose, a set of expert meetings (telephone, face-to-face, web-based) was conducted and the importance of each element of the catalogue was assessed as well as its implementation. A catalogue of requirements with 138 requirements was consented. It is structured into ten sections: 1. Study documentation; 2. Selection of instruments; 3. Study implementation, 4. Organizational structure; 5. Qualification and certification; 6. Participant recruitment; 7. Preparation, conduct and follow-up processing of examinations; 8. Study logistics and maintenance, 9. Data capture and data management; 10. Reporting and monitoring. In total, 41 elements were categorized as being essential, 91 as important, and 6 as less important. The catalogue of requirements provides a guideline to improve the preparation and operation of cohort studies. The evaluation of the importance and degree of implementation of requirements depended on the study design. With adaptations, the catalogue might be transferable to other study types.

Age, time period, and birth cohort differences in self-esteem: Reexamining a cohort-sequential longitudinal study.

PubMed

Twenge, Jean M; Carter, Nathan T; Campbell, W Keith

2017-05-01

Orth, Trzesniewski, and Robins (2010) concluded that the nationally representative Americans' Changing Lives (ACL) cohort-sequential study demonstrated moderate to large age differences in self-esteem, and no birth cohort (generational) differences in the age trajectory. In a reanalysis of these data using 2 different statistical techniques, we find significant increases in self-esteem that could be attributed to birth cohort or time period. First, hierarchical linear modeling analyses with birth cohort as a continuous variable (vs. the multiple group formulation used by Orth et al.) find that birth cohort has a measurable influence on self-esteem through its interaction with age. Participants born in later years (e.g., 1960) were higher in self-esteem and were more likely to increase in self-esteem as they aged than participants born in earlier years (e.g., 1920). However, the estimated age trajectory up to age 60 is similar in Orth et al.'s results and in the results from our analyses including cohort. Second, comparing ACL respondents of the same age in 1986 versus 2002 (a time-lag design) yields significant birth cohort differences in self-esteem, with 2002 participants of the same age higher in self-esteem than those in 1986. Combined with some previous studies finding significant increases in self-esteem and positive self-views over time, these results suggest that cultural change in the form of cohort and time period cannot be ignored as influences in cross-sectional and longitudinal studies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

How does the size and shape of local populations in China compare to general anthropometric surveys currently used for product design?

PubMed

Daniell, Nathan; Fraysse, François; Paul, Gunther

2012-01-01

Anthropometry has long been used for a range of ergonomic applications & product design. Although products are often designed for specific cohorts, anthropometric data are typically sourced from large scale surveys representative of the general population. Additionally, few data are available for emerging markets like China and India. This study measured 80 Chinese males that were representative of a specific cohort targeted for the design of a new product. Thirteen anthropometric measurements were recorded and compared to two large databases that represented a general population, a Chinese database and a Western database. Substantial differences were identified between the Chinese males measured in this study and both databases. The subjects were substantially taller, heavier and broader than subjects in the older Chinese database. However, they were still substantially smaller, lighter and thinner than Western males. Data from current Western anthropometric surveys are unlikely to accurately represent the target population for product designers and manufacturers in emerging markets like China.

The Environment and Reproductive Health (EARTH) Study: A Prospective Preconception Cohort.

PubMed

Messerlian, Carmen; Williams, Paige L; Ford, Jennifer B; Chavarro, Jorge E; Mínguez-Alarcón, Lidia; Dadd, Ramace; Braun, Joseph M; Gaskins, Audrey J; Meeker, John D; James-Todd, Tamarra; Chiu, Yu-Han; Nassan, Feiby L; Souter, Irene; Petrozza, John; Keller, Myra; Toth, Thomas L; Calafat, Antonia M; Hauser, Russ

2018-02-01

The Environment and Reproductive Health (EARTH) Study is an ongoing prospective preconception cohort designed to investigate the impact of environmental, nutritional, and lifestyle factors among both women and men on fertility and pregnancy outcomes. The EARTH Study recruits women 18 to 45 years and men 18 to 55 years seeking fertility evaluation and treatment at the Massachusetts General Hospital (MGH) Fertility Center, Boston, USA. Women and men are eligible to join either independently or as a couple. Participants are followed from study entry throughout each fertility treatment cycle, once per trimester of pregnancy (for those achieving pregnancy), and up to labor and delivery, or until they discontinue treatment or withdraw from the study. The study collects biological samples, self-reported questionnaire data (including a food frequency questionnaire) and clinically abstracted information. As of June 2017, the study cohort included 799 women and 487 men (447 couples; 40 men joined without female partners). Women were on average 34.7 years old at time of enrolment and predominantly Caucasian (81%), educated (49% have a graduate degree), and nulliparous (83%). Men were on average 36.6 years at baseline and mostly Caucasian (86%) and never-smokers (67%). The EARTH Study is one of the few cohorts designed to examine multiple potentially critical windows of vulnerability, including the paternal and maternal preconception windows and the periconception and prenatal windows in pregnancy. It is also one of the few human studies that has assessed potential interactions between environmental exposures and dietary factors.

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.

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.

Prevalent new-user cohort designs for comparative drug effect studies by time-conditional propensity scores.

PubMed

Suissa, Samy; Moodie, Erica E M; Dell'Aniello, Sophie

2017-04-01

Studies of the real-world comparative effectiveness of drugs conducted using computerized healthcare databases typically involve an incident new-user cohort design for head-to-head comparisons between two medications, using exclusively treatment-naïve patients. However, the desired contrast often involves one new drug compared with an older drug, of which many users of the new drug may have switched from, seriously restricting the scope of incident new-user studies. We introduce prevalent new-user cohort designs for head-to-head comparative drug effect studies, where incident new users are scarce. We define time-based and prescription-based exposure sets to compute time-conditional propensity scores of initiating the newer drug and to identify matched subjects receiving the comparator drug. We illustrate this approach using data from the UK's Clinical Practice Research Datalink to evaluate whether the newer glucagon-like peptide-1 receptor agonists (GLP-1 analogs) used to treat type 2 diabetes increase the risk of heart failure, in comparison with the older similarly indicated sulfonylureas. Of the 170 031 users of antidiabetic agents from 2000 onwards, 79 682 used sulfonylureas (first use 2000), while 6196 used GLP-1 analogs (first use 2007), 75% of which had previously used a sulfonylurea. After matching each GLP-1 analog user to a sulfonylurea user on the time-conditional propensity scores from prescription-based exposure sets, the hazard ratio of heart failure with GLP-1 use was 0.73 (95%CI: 0.57-0.93). The proposed prevalent new-user cohort design for comparative drug effects studies allows the use of all or most patients exposed to the newer drug, thus permitting a more comprehensive assessment of a new drug's safety. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Apparent and internal validity of a Monte Carlo-Markov model for cardiovascular disease in a cohort follow-up study.

PubMed

Nijhuis, Rogier L; Stijnen, Theo; Peeters, Anna; Witteman, Jacqueline C M; Hofman, Albert; Hunink, M G Myriam

2006-01-01

To determine the apparent and internal validity of the Rotterdam Ischemic heart disease & Stroke Computer (RISC) model, a Monte Carlo-Markov model, designed to evaluate the impact of cardiovascular disease (CVD) risk factors and their modification on life expectancy (LE) and cardiovascular disease-free LE (DFLE) in a general population (hereinafter, these will be referred to together as (DF)LE). The model is based on data from the Rotterdam Study, a cohort follow-up study of 6871 subjects aged 55 years and older who visited the research center for risk factor assessment at baseline (1990-1993) and completed a follow-up visit 7 years later (original cohort). The transition probabilities and risk factor trends used in the RISC model were based on data from 3501 subjects (the study cohort). To validate the RISC model, the number of simulated CVD events during 7 years' follow-up were compared with the observed number of events in the study cohort and the original cohort, respectively, and simulated (DF)LEs were compared with the (DF)LEs calculated from multistate life tables. Both in the study cohort and in the original cohort, the simulated distribution of CVD events was consistent with the observed number of events (CVD deaths: 7.1% v. 6.6% and 7.4% v. 7.6%, respectively; non-CVD deaths: 11.2% v. 11.5% and 12.9% v. 13.0%, respectively). The distribution of (DF)LEs estimated with the RISC model consistently encompassed the (DF)LEs calculated with multistate life tables. The simulated events and (DF)LE estimates from the RISC model are consistent with observed data from a cohort follow-up study.

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…

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…

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

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.

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.

Facilitating the Development of Study Skills through a Blended Learning Approach

ERIC Educational Resources Information Center

Smith, Julian; Groves, Mark; Bowd, Belinda; Barber, Alison

2012-01-01

This study examined the effectiveness of a Blended Learning (BL) environment designed to facilitate the learning of study skills with a large (over 200) and diverse undergraduate student cohort in a Higher Education (HE) institution in the UK. A BL environment was designed using the model provided by Kerres & De Witt (2003), and was also…

The Subjective Visual Vertical: Validation of a Simple Test

ERIC Educational Resources Information Center

Tesio, Luigi; Longo, Stefano; Rota, Viviana

2011-01-01

The study sought to provide norms for a simple test of visual perception of verticality (subjective visual vertical). The study was designed as a cohort study with a balanced design. The setting was the Rehabilitation Department of a University Hospital. Twenty-two healthy adults, of 23-58 years, 11 men (three left handed) and 11 women (three left…

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

Cancer incidence and mortality in workers employed at a transformer manufacturing plant: update to a cohort study.

PubMed

Yassi, Annalee; Tate, Robert B; Routledge, Michael

2003-07-01

This study is an extension of a previously published analysis of cancer mortality in a transformer manufacturing plant where there had been extensive use of mineral oil transformer fluid. The objectives of the present study were to update the mortality analysis and include deaths for the past 6 years as well as to do an analysis of cancer incidence of the cohort. A cohort of 2,222 males working at a transformer manufacturing plant between 1946 and 1975 was constructed. Using a classical historical cohort study design, cancer incidence and mortality were determined through record linkage with Canadian provincial and national registries. The rates of cancer incidence and mortality experienced by this cohort were compared to that of the Canadian male population. A statistically significant increased risk of developing and dying of pancreatic cancer was found but not an increase in overall cancer mortality. This was consistent with the previous report from this group. Interestingly, the cohort demonstrated a statistically significant risk of overall cancer incidence and specific increased incidence of gallbladder cancer. This study contributes further evidence to the growing body of literature indicating the carcinogenic properties of mineral oils used in occupational settings, in particular those used prior to 1970s. Copyright 2003 Wiley-Liss, Inc.

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.

Eczema in early life: Genetics, the skin barrier, and lessons learned from birth cohort studies

PubMed Central

Biagini Myers, Jocelyn M.; Khurana Hershey, Gurjit K.

2010-01-01

Eczema is a chronic inflammatory disorder of the skin that affects up to 30% of children. It often afflicts infants in the first few months of life and can be the first indicator of the atopic march. Recent results from birth cohort studies have uncovered novel information regarding genetic and environmental factors that promote the development of eczema. Birth cohort studies provide an optimal study design to elucidate these associations and prospectively track longitudinal data including exposure assessment and health outcomes from birth into early life and childhood. This is especially relevant for eczema given the age specific emergence of this disease. In this review, we will provide a general overview of pediatric eczema and discuss the important findings in the literature with respect to genetics and environmental exposures, highlighting those derived from birth cohort studies. Additionally, we will review how these relate to the atopic march, the hygiene hypothesis and the integrity of the skin barrier. PMID:20739029

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

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.

A non-interventional comparative study of the 20:1 combination of cafedrine/theodrenaline versus ephedrine for the treatment of intra-operative arterial hypotension: the 'HYPOTENS' study design and rationale.

PubMed

Eberhart, Leopold; Geldner, Götz; Huljic, Susanne; Marggraf, Kerstin; Keller, Thomas; Koch, Tilo; Kranke, Peter

2018-06-01

To compare the effectiveness of 20:1 cafedrine/theodrenaline approved for use in Germany to ephedrine in the restoration of arterial blood pressure and on post-operative outcomes in patients with intra-operative arterial hypotension of any origin under standard clinical practice conditions. 'HYPOTENS' is a national, multi-center, prospective, open-label, two-armed, non-interventional study. Effectiveness and post-operative outcome following cafedrine/theodrenaline or ephedrine therapy will be evaluated in two cohorts of hypotensive patients. Cohort A includes patients aged ≥50 years with ASA-classification 2-4 undergoing non-emergency surgical procedures under general anesthesia. Cohort B comprises patients undergoing Cesarean section under spinal anesthesia. Participating surgical departments will be assigned to a treatment arm by routinely used anti-hypotensive agent. To minimize bias, matched department pairs will be compared in a stratified selection process. The composite primary end-point is the lower absolute deviation from individually determined target blood pressure (IDTBP) and the incidence of heart rate ≥100 beats/min in the first 15 min. Secondary end-points include incidence and degree of early post-operative delirium (cohort A), severity of fetal acidosis in the newborn (cohort B), upper absolute deviation from IDTBP, percentage increase in systolic blood pressure, and time to IDTBP. This open-label, non-interventional study design mirrors daily practice in the treatment of patients with intra-operative hypotension and ensures full treatment decision autonomy with respect to each patient's individual condition. Selection of participating sites by a randomization process addresses bias without interfering with the non-interventional nature of the study. First results are expected in 2018. ClinicalTrials.gov identifier: NCT02893241; DRKS identifier: DRKS00010740.

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.

Pediatric Severe Sepsis in US Children’s Hospitals

PubMed Central

Balamuth, Fran; Weiss, Scott L.; Neuman, Mark I.; Scott, Halden; Brady, Patrick W.; Paul, Raina; Farris, Reid W.D.; McClead, Richard; Hayes, Katie; Gaieski, David; Hall, Matt; Shah, Samir S.; Alpern, Elizabeth R.

2014-01-01

Objective To compare the prevalence, resource utilization, and mortality for pediatric severe sepsis identified using two established identification strategies. Design Observational cohort study from 2004–2012. Setting Forty-four pediatric hospitals contributing data to the Pediatric Health Information Systems database. Patients Children ≤18 years of age. Measurements and Main Results We identified patients with severe sepsis or septic shock by using two International Classification of Diseases, 9th edition-Clinical Modification (ICD9-CM) based coding strategies: 1) combinations of ICD9-CM codes for infection plus organ dysfunction (combination code cohort); 2) ICD9-CM codes for severe sepsis and septic shock (sepsis code cohort). Outcomes included prevalence of severe sepsis, as well as hospital and intensive care unit (ICU) length of stay (LOS), and mortality. Outcomes were compared between the two cohorts examining aggregate differences over the study period and trends over time. The combination code cohort identified, 176,124 hospitalizations (3.1% of all hospitalizations), while the sepsis code cohort identified 25,236 hospitalizations (0.45%), a 7-fold difference. Between 2004 and 2012, the prevalence of sepsis increased from 3.7% to 4.4% using the combination code cohort and from 0.4% to 0.7% using the sepsis code cohort (p<0.001 for trend in each cohort). LOS (hospital and ICU) and costs decreased in both cohorts over the study period (p<0.001). Overall hospital mortality was higher in the sepsis code cohort than the combination code cohort (21.2%, (95% CI: 20.7–21.8 vs. 8.2%,(95% CI: 8.0–8.3). Over the 9 year study period, there was an absolute reduction in mortality of 10.9% (p<0.001) in the sepsis code cohort and 3.8% (p<0.001) in the combination code cohort. Conclusions Prevalence of pediatric severe sepsis increased in the studied US children’s hospitals over the past 9 years, though resource utilization and mortality decreased. Epidemiologic estimates of pediatric severe sepsis varied up to 7-fold depending on the strategy used for case ascertainment. PMID:25162514

Patient Decision Aids Improve Decision Quality and Patient Experience and Reduce Surgical Rates in Routine Orthopaedic Care: A Prospective Cohort Study.

PubMed

Sepucha, Karen; Atlas, Steven J; Chang, Yuchiao; Dorrwachter, Janet; Freiberg, Andrew; Mangla, Mahima; Rubash, Harry E; Simmons, Leigh H; Cha, Thomas

2017-08-02

Patient decision aids are effective in randomized controlled trials, yet little is known about their impact in routine care. The purpose of this study was to examine whether decision aids increase shared decision-making when used in routine care. A prospective study was designed to evaluate the impact of a quality improvement project to increase the use of decision aids for patients with hip or knee osteoarthritis, lumbar disc herniation, or lumbar spinal stenosis. A usual care cohort was enrolled before the quality improvement project and an intervention cohort was enrolled after the project. Participants were surveyed 1 week after a specialist visit, and surgical status was collected at 6 months. Regression analyses adjusted for clustering of patients within clinicians and examined the impact on knowledge, patient reports of shared decision-making in the visit, and surgical rates. With 550 surveys, the study had 80% to 90% power to detect a difference in these key outcomes. The response rates to the 1-week survey were 70.6% (324 of 459) for the usual care cohort and 70.2% (328 of 467) for the intervention cohort. There was no significant difference (p > 0.05) in any patient characteristic between the 2 cohorts. More patients received decision aids in the intervention cohort at 63.6% compared with the usual care cohort at 27.3% (p = 0.007). Decision aid use was associated with higher knowledge scores, with a mean difference of 18.7 points (95% confidence interval [CI], 11.4 to 26.1 points; p < 0.001) for the usual care cohort and 15.3 points (95% CI, 7.5 to 23.0 points; p = 0.002) for the intervention cohort. Patients reported more shared decision-making (p = 0.009) in the visit with their surgeon in the intervention cohort, with a mean Shared Decision-Making Process score (and standard deviation) of 66.9 ± 27.5 points, compared with the usual care cohort at 62.5 ± 28.6 points. The majority of patients received their preferred treatment, and this did not differ by cohort or decision aid use. Surgical rates were lower in the intervention cohort for those who received the decision aids at 42.3% compared with 58.8% for those who did not receive decision aids (p = 0.023) and in the usual care cohort at 44.3% for those who received decision aids compared with 55.7% for those who did not receive them (p = 0.45). The quality improvement project successfully integrated patient decision aids into a busy orthopaedic clinic. When used in routine care, decision aids are associated with increased knowledge, more shared decision-making, and lower surgical rates. There is increasing pressure to design systems of care that inform and involve patients in decisions about elective surgery. In this study, the authors found that patient decision aids, when used as part of routine orthopaedic care, were associated with increased knowledge, more shared decision-making, higher patient experience ratings, and lower surgical rates.

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.

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

Impact of Exercise Counseling on Physical Function in Chronic Kidney Disease: An Observational Study

PubMed Central

Storsley, Leroy J.; Hiebert, Brett M.; Nelko, Serena; Cheskin, Lawrence J.; McAdams-DeMarco, Mara A.; Rigatto, Claudio

2018-01-01

Background: Individuals with chronic kidney disease (CKD) have low levels of physical activity and physical function. Although guidelines endorse exercise counseling for individuals with CKD, it is not yet part of routine care. Objective: We investigated the effect of attending a real-life exercise counseling clinic (ECC) on physical function in individuals with CKD. Design: Retrospective analysis of prospectively collected observational data with quasi-experimental design. Setting and Participants: Patients with all stages of CKD registered in a large provincial renal program were eligible. The exposed cohort who attended the ECC between January 1, 2011, and March 15, 2014, included 214 individuals. The control cohort included 292 individuals enrolled in an observational study investigating longitudinal change in frailty during the same time period. Predictor/Factor: Attendance at an ECC. Outcomes and Measurements: Change in physical function as measured by Short Physical Performance Battery (SPPB) score, physical activity level (Human Activity Profile [HAP]/Physical Activity Scale for the Elderly [PASE]), and health-related quality of life (HRQOL; EQ5D/VAS) over 1 year. Results: Eighty-seven individuals in the ECC cohort and 125 participants in the control cohort completed 1-year follow-up. Baseline median SPPB score was 10 (interquartile range [IQR]: 9-12) and 9 (IQR: 7-11) in the ECC and control cohorts, respectively (P < .01). At 1 year, SPPB scores were 10 (IQR: 8-12) and 9 (IQR: 6-11) in the ECC and control cohorts, respectively (P = .04). Mean change in SPPB over 1 year was not significantly different between groups: −0.33 (95% confidence interval [CI]: −0.81 to 0.15) in ECC and −0.22 (95% CI: −0.61 to 0.17) in control (P = .72). There was no significant difference in the proportion of individuals in each cohort with an increase/decrease in SPPB score over time. There was no significant change in physical activity or HRQOL over time between groups. Limitations: Quasi-experimental design, low rate of follow-up attendance. Conclusions: In this pragmatic study, exercise counseling had no significant effect on change in SPPB score, suggesting that a single exercise counseling session alone is inadequate to improve physical function in CKD. PMID:29487746

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.

Design of the Chicago Health and Aging Project (CHAP).

PubMed

Bienias, Julia L; Beckett, Laurel A; Bennett, David A; Wilson, Robert S; Evans, Denis A

2003-10-01

The design of the Chicago Health and Aging Project (CHAP) is described. CHAP is a longitudinal population study of common chronic health problems of older persons, especially of risk factors for incident Alzheimer's disease, in a biracial neighborhood of the south side of Chicago. Special attention is given to three unusual design features of the study. One feature is that clinical evaluation for Alzheimer's disease is confined to a stratified random sample of all participants. This feature results in substantial cost savings and substantially less bias than screening approaches but has the disadvantages of adding analytic complexity and requiring the use of indirect means to identify a disease-free cohort for the development of incident Alzheimer's disease. The second unusual feature is efficiently combining in analyses the successive independent multiple samples that are drawn, one from each data collection cycle. The third unusual feature is entering successive age cohorts of community residents into the study as they attain 65 years of age. This has the advantages of enhancing direct investigation of the effect of age on the action of risk factors for Alzheimer's disease and direct examination of cohort effects. The interaction of these features is described, especially as they pertain to a study in which data are collected in successive waves. The results from these waves must be combined for effective analysis of the relation among risk factors and incident disease.

Better cancer biomarker discovery through better study design.

PubMed

Rundle, Andrew; Ahsan, Habibul; Vineis, Paolo

2012-12-01

High-throughput laboratory technologies coupled with sophisticated bioinformatics algorithms have tremendous potential for discovering novel biomarkers, or profiles of biomarkers, that could serve as predictors of disease risk, response to treatment or prognosis. We discuss methodological issues in wedding high-throughput approaches for biomarker discovery with the case-control study designs typically used in biomarker discovery studies, especially focusing on nested case-control designs. We review principles for nested case-control study design in relation to biomarker discovery studies and describe how the efficiency of biomarker discovery can be effected by study design choices. We develop a simulated prostate cancer cohort data set and a series of biomarker discovery case-control studies nested within the cohort to illustrate how study design choices can influence biomarker discovery process. Common elements of nested case-control design, incidence density sampling and matching of controls to cases are not typically factored correctly into biomarker discovery analyses, inducing bias in the discovery process. We illustrate how incidence density sampling and matching of controls to cases reduce the apparent specificity of truly valid biomarkers 'discovered' in a nested case-control study. We also propose and demonstrate a new case-control matching protocol, we call 'antimatching', that improves the efficiency of biomarker discovery studies. For a valid, but as yet undiscovered, biomarker(s) disjunctions between correctly designed epidemiologic studies and the practice of biomarker discovery reduce the likelihood that true biomarker(s) will be discovered and increases the false-positive discovery rate. © 2012 The Authors. European Journal of Clinical Investigation © 2012 Stichting European Society for Clinical Investigation Journal Foundation.

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

Postnatal paternal depressive symptoms associated with fathers' subsequent parenting: findings from the Millennium Cohort Study.

PubMed

Nath, Selina; Russell, Ginny; Ford, Tamsin; Kuyken, Willem; Psychogiou, Lamprini

2015-12-01

Impaired parenting may lie on the causal pathway between paternal depression and children's outcomes. We use the first four surveys of the Millennium Cohort Study to investigate the association between paternal depressive symptoms and fathers' parenting (negative, positive and involvement). Findings suggest that postnatal paternal depressive symptoms are associated with fathers' negative parenting. This has implications for the design of intervention programmes for parents with depression and young children. © The Royal College of Psychiatrists 2015.

iPad versus Traditional Tools in Art and Design: A Complementary Association

ERIC Educational Resources Information Center

Souleles, Nicos

2017-01-01

There is continuous debate on the role of digital media tools in art and design Higher Education, and in particular their potential contribution towards teaching and learning. The related literature indicates that there is a dichotomy between digital and traditional tools. This study investigates the views of a cohort of art and design students…

Comparison of sexual behavior and HIV risk between two HIV-1 serodiscordant couple cohorts: the CHAVI 002 study.

PubMed

Ritchie, Adam J; Kuldanek, Kristin; Moodie, Zoe; Wang, Z Maggie; Fox, Julie; Nsubuga, Rebecca N; Legg, Kenneth; Birabwa, Esther F; Kaleebu, Pontiano; McMichael, Andrew J; Watera, Christine; Goonetilleke, Nilu; Fidler, Sarah

2012-01-01

The CHAVI002 study was designed to characterize immune responses, particularly HIV-specific T-cell responses, amongst 2 cohorts of HIV-exposed seronegative (HESN) individuals. The absence of a clear definition of HESNs has impaired comparison of research within and between such cohorts. This report describes two distinct HESN cohorts and attempts to quantify HIV exposure using a 'HIV risk index' (RI) model. HIV serodiscordant couples (UK; 24, Uganda; 72) and HIV unexposed seronegative (HUSN) controls (UK; 14, Uganda; 26 couples, 3 individuals) completed sexual behavior questionnaires every 3 months over a 9 month period. The two cohorts were heterogeneous, with most HESNs in the UK men who have sex with men (MSM), while all HESNs in Uganda were in heterosexual relationships. Concordance of responses between partners was determined. Each participant's sexual behavior score (SBS) was estimated based on the number and type of unprotected sex acts carried out in defined time periods. Independent HIV acquisition risk factors (partner plasma viral load, STIs, male circumcision, pregnancy) were integrated with the SBS, generating a RI for each HESN. 96 HIV serodiscordant couples completed 929 SBQs. SBSs remained relatively stable amongst the UK cohort, whilst decreasing from Visit 1 to 2 in the Ugandan cohort. Compared to the Ugandan cohort, SBSs and RIs in the UK cohort were lower at visit 1, and generally higher at later visits. Differences between the cohorts, with lower rates of ART use in Uganda and higher risk per-act sex in the UK, had major impacts on the SBSs and RIs of each cohort. There was one HIV transmission event in the UK cohort. Employment of a risk quantification model facilitated quantification and comparison of HIV acquisition risk across two disparate HIV serodiscordant couple cohorts.

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

PubMed Central

2013-01-01

Background The prospective cohort study design is ideal for examining diseases of public health importance, as its inherent temporal nature renders it advantageous for studying early life influences on health outcomes and research questions of aetiological significance. This paper will describe the development and characteristics of the All Our Babies (AOB) study, a prospective pregnancy cohort in Calgary, Alberta, Canada designed to examine determinants of maternal, infant, and child outcomes and identify barriers and facilitators in health care utilization. Methods Women were recruited from health care offices, communities, and through Calgary Laboratory Services before 25 weeks gestation from May 2008 to December 2010. Participants completed two questionnaires during pregnancy, a third at 4 months postpartum, and are currently being followed-up with questionnaires at 12, 24, and 36 months. Data was collected on pregnancy history, demographics, lifestyle, health care utilization, physical and mental health, parenting, and child developmental outcomes and milestones. In addition, biological/serological and genetic markers can be extracted from collected maternal and cord blood samples. Results A total of 4011 pregnant women were eligible for recruitment into the AOB study. Of this, 3388 women completed at least one survey. The majority of participants were less than 35 years of age, Caucasian, Canadian born, married or in a common-law relationship, well-educated, and reported household incomes above the Calgary median. Women who discontinued after the first survey (n=123) were typically younger, non-Caucasian, foreign-born, had lower education and household income levels, were less likely to be married or in a common-law relationship, and had poor psychosocial health in early pregnancy. In general, AOB participants reflect the pregnant and parenting population at local and provincial levels, and perinatal indicators from the study are comparable to perinatal surveillance data. Conclusions The extensive and rich data collected in the AOB cohort provides the opportunity to answer complex questions about the relationships between biology, early experiences, and developmental outcomes. This cohort will contribute to the understanding of the biologic mechanisms and social/environmental pathways underlying associations between early and later life outcomes, gene-environment interactions, and developmental trajectories among children. PMID:23445747

The 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.

Pregnancy as a Window to Future Cardiovascular Health: Design and Implementation of the nuMoM2b Heart Health Study.

PubMed

Haas, David M; Ehrenthal, Deborah B; Koch, Matthew A; Catov, Janet M; Barnes, Shannon E; Facco, Francesca; Parker, Corette B; Mercer, Brian M; Bairey-Merz, C Noel; Silver, Robert M; Wapner, Ronald J; Simhan, Hyagriv N; Hoffman, Matthew K; Grobman, William A; Greenland, Philip; Wing, Deborah A; Saade, George R; Parry, Samuel; Zee, Phyllis C; Reddy, Uma M; Pemberton, Victoria L; Burwen, Dale R

2016-03-15

The National Institute of Child Health and Human Development's Nulliparous Pregnancy Outcomes Study-Monitoring Mothers-to-Be (nuMoM2b) Heart Health Study (HHS) was designed to investigate the relationships between adverse pregnancy outcomes and modifiable risk factors for cardiovascular disease. The ongoing nuMoM2b-HHS, which started in 2013, is a prospective follow-up of the nuMoM2b cohort, which included 10,038 women recruited between 2010 and 2013 from 8 centers across the United States who were initially observed over the course of their first pregnancies. In this report, we detail the design and study procedures of the nuMoM2b-HHS. Women in the pregnancy cohort who consented to be contacted for participation in future studies were approached at 6-month intervals to ascertain health information and to maintain ongoing contact. Two to 5 years after completion of the pregnancy documented in the nuMoM2b, women in the nuMoM2b-HHS were invited to an in-person study visit. During this visit, they completed psychosocial and medical history questionnaires and had clinical measurements and biological specimens obtained. A subcohort of participants who had objective assessments of sleep-disordered breathing during pregnancy were asked to repeat this investigation. This unique prospective observational study includes a large, geographically and ethnically diverse cohort, rich depth of phenotypic information about adverse pregnancy outcomes, and clinical data and biospecimens from early in the index pregnancy onward. Data obtained from this cohort will provide mechanistic and clinical insights into how data on a first pregnancy can provide information about the potential development of subsequent risk factors for cardiovascular disease. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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…

The Hokkaido Birth Cohort Study on Environment and Children's Health: cohort profile-updated 2017.

PubMed

Kishi, Reiko; Araki, Atsuko; Minatoya, Machiko; Hanaoka, Tomoyuki; Miyashita, Chihiro; Itoh, Sachiko; Kobayashi, Sumitaka; Ait Bamai, Yu; Yamazaki, Keiko; Miura, Ryu; Tamura, Naomi; Ito, Kumiko; Goudarzi, Houman

2017-05-18

The Hokkaido Study on Environment and Children's Health is an ongoing study consisting of two birth cohorts of different population sizes: the Sapporo cohort and the Hokkaido cohort. Our primary study goals are (1) to examine the effects of low-level environmental chemical exposures on birth outcomes, including birth defects and growth retardation; (2) to follow the development of allergies, infectious diseases, and neurobehavioral developmental disorders and perform a longitudinal observation of child development; (3) to identify high-risk groups based on genetic susceptibility to environmental chemicals; and (4) to identify the additive effects of various chemicals, including tobacco smoking. The purpose of this report is to update the progress of the Hokkaido Study, to summarize the recent results, and to suggest future directions. In particular, this report provides the basic characteristics of the cohort populations, discusses the population remaining in the cohorts and those who were lost to follow-up at birth, and introduces the newly added follow-up studies and case-cohort study design. In the Sapporo cohort of 514 enrolled pregnant women, various specimens, including maternal and cord blood, maternal hair, and breast milk, were collected for the assessment of exposures to dioxins, polychlorinated biphenyls, organochlorine pesticides, perfluoroalkyl substances, phthalates, bisphenol A, and methylmercury. As follow-ups, face-to-face neurobehavioral developmental tests were conducted at several different ages. In the Hokkaido cohort of 20,926 enrolled pregnant women, the prevalence of complicated pregnancies and birth outcomes, such as miscarriage, stillbirth, low birth weight, preterm birth, and small for gestational age were examined. The levels of exposure to environmental chemicals were relatively low in these study populations compared to those reported previously. We also studied environmental chemical exposure in association with health outcomes, including birth size, neonatal hormone levels, neurobehavioral development, asthma, allergies, and infectious diseases. In addition, genetic and epigenetic analyses were conducted. The results of this study demonstrate the effects of environmental chemical exposures on genetically susceptible populations and on DNA methylation. Further study and continuous follow-up are necessary to elucidate the combined effects of chemical exposure on health outcomes.

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

Designing clinical trials for amblyopia

PubMed Central

Holmes, Jonathan M.

2015-01-01

Randomized clinical trial (RCT) study design leads to one of the highest levels of evidence, and is a preferred study design over cohort studies, because randomization reduces bias and maximizes the chance that even unknown confounding factors will be balanced between treatment groups. Recent randomized clinical trials and observational studies in amblyopia can be taken together to formulate an evidence-based approach to amblyopia treatment, which is presented in this review. When designing future clinical studies of amblyopia treatment, issues such as regression to the mean, sample size and trial duration must be considered, since each may impact study results and conclusions. PMID:25752747

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-30

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

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2010-05-18

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

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2012-03-16

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77 FR 60438 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

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

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77 FR 69845 - Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort

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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

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

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.

The Minnesota Adolescent Community Cohort Study: Design and Baseline Results

PubMed Central

Forster, Jean; Chen, Vincent; Perry, Cheryl; Oswald, John; Willmorth, Michael

2014-01-01

The Minnesota Adolescent Community Cohort (MACC) Study is a population-based, longitudinal study that enrolled 3636 youth from Minnesota and 605 youth from comparison states age 12 to 16 years in 2000–2001. Participants have been surveyed by telephone semi-annually about their tobacco-related attitudes and behaviors. The goals of the study are to evaluate the effects of the Minnesota Youth Tobacco Prevention Initiative and its shutdown on youth smoking patterns, and to better define the patterns of development of tobacco use in adolescents. A multilevel sample was constructed representing individuals, local jurisdictions and the entire state, and data are collected to characterize each of these levels. This paper presents the details of the multilevel study design. We also provide baseline information about MACC participants including demographics and tobacco-related attitudes and behaviors. This paper describes smoking prevalence at the local level, and compares MACC participants to the state as a whole. PMID:21360063

Dietary guideline adherence index and kidney measures in the framingham heart study

USDA-ARS?s Scientific Manuscript database

BACKGROUND: No observational studies have directly considered dietary guidelines when examining the prospective association between dietary intake and kidney measures. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: We examined participants who attended examinations 7 (1998-2001) a...

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/.

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.

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

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.

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

Comparison of motor diagnoses by Chicago Classification versions 2.0 and 3.0 on esophageal high-resolution manometry.

PubMed

Patel, A; Cassell, B; Sainani, N; Wang, D; Shahid, B; Bennett, M; Mirza, F A; Munigala, S; Gyawali, C P

2017-07-01

The Chicago Classification (CC) uses high-resolution manometry (HRM) software tools to designate esophageal motor diagnoses. We evaluated changes in diagnostic designations between two CC versions, and determined motor patterns not identified by either version. In this observational cohort study of consecutive patients undergoing esophageal HRM over a 6-year period, proportions meeting CC 2.0 and 3.0 criteria were segregated into esophageal outflow obstruction, hypermotility, and hypomotility disorders. Contraction wave abnormalities (CWA), and 'normal' cohorts were recorded. Symptom burden was characterized using dominant symptom intensity and global symptom severity. Motor diagnoses, presenting symptoms, and symptom burden were compared between CC 2.0 and 3.0, and in cohorts not meeting CC diagnoses. Of 2569 eligible studies, 49.9% met CC 2.0 criteria, but only 40.3% met CC 3.0 criteria (P<.0001). Between CC 2.0 and 3.0, 82.8% of diagnoses were concordant. Discordance resulted from decreasing proportions of hypermotility (4.4%) and hypomotility (9.0%) disorders, and increase in 'normal' designations (13.0%); esophageal outflow obstruction showed the least variation between CC versions. Symptom burden was higher with CC 3.0 diagnoses (P≤.005) but not with CC 2.0 diagnoses (P≥.1). Within 'normal' cohorts for both CC versions, CWA were associated with higher likelihood of esophageal symptoms, especially dysphagia, regurgitation, and heartburn, compared to truly normal studies (P≤.02 for each comparison). Despite lower sensitivity, CC 3.0 identifies esophageal motor disorders with higher symptom burden compared to CC 2.0. CWA, which are associated with both transit and perceptive symptoms, are not well identified by either version. © 2017 John Wiley & Sons Ltd.

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

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

Incidence of cancer among UK Gulf war veterans: cohort study

PubMed Central

Macfarlane, Gary J; Biggs, Anne-Marie; Maconochie, Noreen; Hotopf, Matthew; Doyle, Patricia; Lunt, Mark

2003-01-01

Objectives To determine whether incidence rates of cancer are higher in UK service personnel who were deployed in the Gulf war than in those not deployed and whether any increased risk of cancer is related to self reported exposures to potentially hazardous material during the period of deployment. Design A cohort study with follow up from 1 April 1991 (the end of the Gulf war) to 31 July 2002. Participants 51 721 Gulf war veterans and 50 755 service personnel matched for age, sex, rank, service, and level of fitness who were not deployed in the Gulf (the Era cohort). Main outcome measures Incident cancers, identified on the NHS central register. Results There were 270 incident cancers among the Gulf cohort and 269 among the Era cohort (incidence rate ratio 0.99, 95% confidence interval 0.83 to 1.17). There was no excess in site specific cancers among the Gulf cohort. Adjustment for lifestyle factors (smoking and alcohol consumption) did not alter these results. In the Gulf cohort, risk of cancer was not related to multiple vaccinations or exposure to pesticides or depleted uranium during deployment. Conclusion There is no current excess risk of cancer overall nor of site specific cancers in Gulf war veterans. Specific exposures during deployment have not resulted in a subsequent increased risk of cancer. The long latent period for cancer, however, necessitates the continued follow up of these cohorts. PMID:14670879

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

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

Venous thromboembolism in cancer patients receiving neoadjuvant chemotherapy: a systematic review and meta-analysis.

PubMed

Di Nisio, M; Candeloro, M; Rutjes, A W S; Porreca, E

2018-05-13

Venous thromboembolism (VTE) is a frequent complication in cancer patients receiving adjuvant treatment. The risk of VTE during neoadjuvant chemo-radiotherapy remains unclear. This systematic review evaluated the incidence of VTE in patients with cancer receiving neoadjuvant treatment. MEDLINE and EMBASE databases were searched from inception to October 2017. Search results were supplemented with screening of conference proceedings of the American Society of Clinical Oncology (2009-2016) and the International Society of Thrombosis and Haemostasis (2003-2016). Two review authors independently screened titles and abstracts, and extracted data onto standardized forms. Twenty-eight cohort studies (7827 cancer patients, range 11 to 1398) were included. Twenty-five had a retrospective design. Eighteen cohorts included patients with gastrointestinal cancer representing over two-thirds of the whole study population (n = 6002, 78%). In total, 508 of 7768 patients were diagnosed with at least one VTE during neoadjuvant treatment for a pooled VTE incidence of 7% (95% CI, 5% to 10%) in absence of substantial between study heterogeneity. Heterogeneity was not explained by site of cancer or study design characteristics. VTE presented as pulmonary embolism in 22% to 96% of cases (16 cohorts), and it was symptomatic in 22% to 100% of patients (11 cohorts). Highest VTE rates were observed in patients with bladder (10.6%) or esophageal (8.4%) cancer. This review found a relatively high incidence of VTE in cancer patients receiving neoadjuvant therapy in the presence of some between study variation, which deserves further evaluation in prospective studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Development of a Web Portal for Physical Activity and Symptom Tracking in Oncology Patients: Protocol for a Prospective Cohort Study.

PubMed

Marthick, Michael; Dhillon, Haryana M; Alison, Jennifer A; Cheema, Birinder S; Shaw, Tim

2018-05-15

Significant benefits accrue from increasing physical activity levels in people with a history of cancer. Physical activity levels can be increased using behavioral change interventions in this population. Access to Web portals and provision of activity monitors to provide feedback may support behavior change by encouraging patient engagement in physical therapy. The Web portal evaluated in this study will provide a system to monitor physical activity and sleep, for use by both clinician and patient, along with symptom and health-related quality of life tracking capabilities. The aim of this study was to outline a protocol for a feasibility study focused on a Web-based portal that provides activity monitoring and personalized messaging to increase physical activity in people with cancer. Using a longitudinal cohort design, people with cancer will be serially allocated to 3 intervention cohorts of 20 participants each and followed for 10 weeks. Cohort 1 will be provided a wearable activity monitor and access to a Web-based portal. Cohort 2 will receive the same content as Cohort 1 and in addition will receive a weekly activity summary message. Cohort 3 will receive the same content as Cohorts 1 and 2 and in addition will receive a personalized weekly coaching message. Feasibility of the use of the portal is the primary outcome. Results are expected in early 2018. Outcome measures will include goal attainment and completion rate. This study will provide information about the feasibility of investigating eHealth initiatives to promote physical activity in people with cancer. RR1-10.2196/9586. ©Michael Marthick, Haryana M Dhillon, Jennifer A Alison, Birinder S Cheema, Tim Shaw. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 15.05.2018.

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

... 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 Area IV of the Santa...

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...

Dietary Cholesterol Intake and Risk of Lung Cancer: A Meta-Analysis.

PubMed

Lin, Xiaojing; Liu, Lingli; Fu, Youyun; Gao, Jing; He, Yunyun; Wu, Yang; Lian, Xuemei

2018-02-08

Multiple epidemiologic studies have evaluated the relationship between dietary cholesterol and lung cancer risk, but the association is controversial and inconclusive. A meta-analysis of case-control studies and cohort studies was conducted to evaluate the relationship between dietary cholesterol intake and lung cancer risk in this study. A relevant literature search up to October 2017 was performed in Web of Science, PubMed, China National Knowledge Infrastructure, Sinomed, and VIP Journal Integration Platform. Ten case-control studies and six cohort studies were included in the meta-analysis, and the risk estimates were pooled using either fixed or random effects models. The case-control studies with a total of 6894 lung cancer cases and 29,736 controls showed that dietary cholesterol intake was positively associated with lung cancer risk (Odds Ratio = 1.70, 95% Confidence Interval: 1.43-2.03). However, there was no evidence of an association between dietary cholesterol intake and risk of lung cancer among the 241,920 participants and 1769 lung cancer cases in the cohort studies (Relative Risk = 1.08, 95% Confidence Interval: 0.94-1.25). Due to inconsistent results from case-control and cohort studies, it is difficult to draw any conclusion regarding the effects of dietary cholesterol intake on lung cancer risk. Carefully designed and well-conducted cohort studies are needed to identify the association between dietary cholesterol and lung cancer risk.

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.

Change in social status and risk of low birth weight in Denmark: population based cohort study.

PubMed Central

Basso, O.; Olsen, J.; Johansen, A. M.; Christensen, K.

1997-01-01

OBJECTIVE: To estimate the risk of having a low birthweight infant associated with changes in social, environmental, and genetic factors. DESIGN: Population based, historical cohort study using the Danish medical birth registry and Statistic Denmark's fertility database. SUBJECTS: All women who had a low birthweight infant (< 2500 g) (index birth) and a subsequent liveborn infant (outcome birth) in Denmark between 1980 and 1992 (exposed cohort, n = 11,069) and a random sample of the population who gave birth to an infant weighing > or = 2500 g and to a subsequent liveborn infant (unexposed cohort, n = 10,211). MAIN OUTCOME MEASURES: Risk of having a low birthweight infant in the outcome birth as a function of changes in male partner, area of residence, type of job, and social status between the two births. RESULTS: Women in the exposed cohort showed a high risk (18.5%) of having a subsequent low birthweight infant while women in the unexposed cohort had a risk of 2.8%. After adjustment for initial social status, a decline in social status increased the absolute risk of having a low birthweight infant by about 5% in both cohorts, though this was significant only in the unexposed cohort. Change of male partner did not modify the risk of low birth weight in either cohort. CONCLUSION: Having had a low birthweight infant and a decline in social status are strong risk factors for having a low birthweight infant subsequently. PMID:9420490

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.

HIV Risk Reduction Among Young Adult Chronic Psychiatric Patients

DTIC Science & Technology

1990-08-28

was noted in a cohort of gay men in California. The human immunodeficiency virus (HIV) was discovered as the cause of AIDS and the HI V antibody...sexual practices among homosexual and bisexual men provide a framework for the development of any prevention program designed to reduce the risk of HIV...and the Multicenter Aids Cohort Study and note that many gay men have significantly reduced the frequency of unprotected anal Intercourse. Winkelstein

Higher serum levels of vitamin D at diagnosis are associated with better survival in a prospective cohort of 1,666 women with breast cancer: A case-cohort analysis in the Pathways Study

PubMed Central

Yao, Song; Kwan, Marilyn L.; Ergas, Isaac J.; Roh, Janise M.; Cheng, Ting-Yuan David; Hong, Chi-Chen; McCann, Susan E.; Tang, Li; Davis, Warren; Liu, Song; Quesenberry, Charles P.; Lee, Marion M.; Ambrosone, Christine B.; Kushi, Lawrence H.

2017-01-01

Importance There are long-standing interests in the potential benefits of vitamin D for preventing breast cancer recurrence and mortality; yet data from prospective cohort studies are limited. Objective We investigated a serum biomarker of vitamin D status, 25-hydroxyvitamin D (25OHD) measured at the time of breast cancer diagnosis, with prognosis. Design The Pathways Study is a prospective cohort study of breast cancer survivors established in 2006. Enrollment was completed in 2013; follow up is ongoing. Setting The cohort was established in Kaiser Permanente Northern California (KPNC), a large integrated healthcare delivery system in San Francisco Bay Area and central valley, California. Participants Women diagnosed with incident invasive breast cancer were typically consented and enrolled within 2 months of diagnosis. The overall enrollment rate was 46%. Participants are followed for health outcomes and comorbidities at 12, 24, 48, 72 and 96 months after baseline interview. A case-cohort design was used for efficiency assay of 25OHD, selecting 1,666 cohort members with serum samples and ensuring representation in the sub-cohort of races and clinical subtypes. Main Outcome Measures Primary outcomes are breast cancer recurrence, second primary cancer (SPC), and death. Results Serum 25OHD concentrations were lower in women with advanced stage tumors, and the lowest in premenopausal women with triple-negative cancer. Levels were also inversely associated with hazards of disease progression and death. Compared with the lowest tertile (T1), women with the highest (T3) 25OHD levels had superior overall survival (OS). This association remained after adjustment for clinical prognostic factors [hazards ratio (HR)=0.72, 95% confidence interval (CI): 0.54, 0.98]. Among premenopausal women, the association with OS was stronger, and there were also associations with breast cancer-specific survival (BCSS) and invasive disease-free survival (IDFS) (OS: HR=0.45, 95% CI, 0.21–0.96; BCSS: HR=0.37, 95% CI, 0.15–0.93; IDFS: HR=0.58, 95% CI, 0.34–1.01; all after full adjustment.) Conclusions and Relevance Serum 25OHD levels were independently associated with breast cancer prognostic characteristics and patient prognosis, most prominently among premenopausal women. Our findings from a large, well-characterized prospective cohort provide compelling observational evidence on associations of vitamin D with lower risk of breast cancer morbidity and mortality. PMID:27832250

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

Overview of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers.

PubMed

Helzlsouer, Kathy J

2010-07-01

The Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP) brought together 10 cohorts to conduct a prospective study of the association between vitamin D status, measured as serum concentrations of 25-hydroxyvitamin D (25(OH)D), and the development of 7 rarer cancer sites: endometrial, esophageal, gastric, kidney, non-Hodgkin lymphoma, ovarian, and pancreatic cancers. The cohorts come from 3 continents, with participants from a wide range of latitude who are racially diverse. Across each cancer site, there was no evidence of a protective association between higher concentrations of 25-hydroxyvitamin D (>75 nmol/L) and cancer outcome. An increased risk at very high levels (> or =100 nmol/L) was noted for pancreatic cancer, confirming previous reports. The articles included in this issue detail the overall design and governance of the project, correlates of vitamin D status, and results from the cancer site-specific investigations. The Vitamin D Pooling Project realizes a major goal of consortium efforts, namely, to rigorously test hypotheses for rarer cancer outcomes that may not be adequately addressed in any one prospective cohort study. The results of this study have application for the planning and conduct of intervention trials, especially in determining potential risks.

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

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 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

Pregnancy gingivitis and causal inference.

PubMed

Niederman, Richard

2013-12-01

The PubMed and Embase databases were searched together with hand searching of the Journal of Periodontology, Journal of Periodontal Research and Journal of Clinical Periodontology. The reference lists of identified articles were also searched. Prospective cohort or cross-sectional studies assessing the effect of pregnancy on gingival inflammation evaluated by the gingival index and/or bleeding on probing were included. Study quality was assessed using the Newcastle-Ottawa scale (NOS). Study assessment and data extraction were carried out independently by two reviewers, with disputes resolved by a third reviewer. Mean values of primary and secondary outcomes were directly pooled and analysed with weighted mean differences (WMDs) and 95% confidence intervals (CIs), considering independently each study design (cohort and cross-sectional). Study specific estimates were pooled with both the fixed- and random-effect models. Forty-four articles representing 33 studies (14 cohort and 19 cross-sectional) were included. Meta-analyses revealed a significantly lower GI in pregnant women in the first term compared with those in their second or third term of pregnancy; a lower mean GI score in post-partum women compared with women in their second [WMD = 0.143; 95% CI (0.031; 0.255); p = 0.012] or third term [WMD = 0.256; 95% CI (0.151; 0.360); p < 0.001] of pregnancy, when considering cohort studies; non-pregnant women had lower mean GI values than women in their second or third term of pregnancy. Small changes in plaque levels were reported. The results of this systematic review confirm that gingival inflammation is significantly increased throughout pregnancy and when comparing pregnant versus post-partum or non-pregnant women, without a concomitant increase in plaque levels. However, this information should be considered with caution, due to the small number of studies included in the meta-analyses, the low quality of the included studies, differences in study design, absence of a periodontal diagnosis at baseline and performance of periodontal treatment in some cases. No conclusions could be drawn regarding secondary outcomes such as microbiological, immunological and patient-centred data, because no meta-analyses were possible for these factors. Future studies with higher quality should be designed to answer these questions.

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

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

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.

Replication of an association of variation in the FOXO3A gene with human longevity using both case–control and longitudinal data

PubMed Central

Soerensen, Mette; Dato, Serena; Christensen, Kaare; McGue, Matt; Stevnsner, Tinna; Bohr, Vilhelm A.; Christiansen, Lene

2010-01-01

Summary Genetic variation in FOXO3A has previously been associated with human longevity. Studies published so far have been case–control studies and hence vulnerable to bias introduced by cohort effects. In this study we extended the previous findings in the cohorts of oldest old Danes (the Danish 1905 cohort, N = 1089) and middle-aged Danes (N = 736), applying a longitudinal study design as well as the case–control study design. Fifteen SNPs were chosen in order to cover the known common variation in FOXO3A. Comparing SNP frequencies in the oldest old with middle-aged individuals, we found association (after correction for multiple testing) of eight SNPs; 4 (rs13217795, rs2764264, rs479744, and rs9400239) previously reported to be associated with longevity and four novel SNPs (rs12206094, rs13220810, rs7762395, and rs9486902 (corrected P-values 0.001–0.044). Moreover, we found association of the haplotypes TAC and CAC of rs9486902, rs10499051, and rs12206094 (corrected P-values: 0.01–0.03) with longevity. Finally, we here present data applying a longitudinal study design; when using follow-up survival data on the oldest old in a longitudinal analysis, we found no SNPs to remain significant after the correction for multiple testing (Bonferroni correction). Hence, our results support and extent the proposed role of FOXO3A as a candidate longevity gene for survival from younger ages to old age, yet not during old age. PMID:20849522

Increased risk of pyogenic liver abscess in patients with alcohol intoxication: A population-based retrospective cohort study.

PubMed

Wang, Yao-Chien; Yang, Kai-Wei; Lee, Tien-Ying Peter; Lin, Cheng-Li; Liaw, Geng-Wang; Hung, Dong-Zong; Kao, Chia-Hung; Chen, Wei-Kung; Yang, Tse-Yen

2017-11-01

We designed a population-based retrospective cohort study to investigate the association between the event of alcohol intoxication and the risk of pyogenic liver abscess. The present study enrolled 245,076 patients with a history of alcohol intoxication from 2000 to 2010 and matched each of them with four comparison patients, with similar mean age and sex ratios. We determined the cumulative incidences and adjusted hazard ratios (aHRs) of liver abscess. A significant association was observed between alcohol intoxication and liver abscess. The incidence density rate of liver abscess was 3.47-fold greater in the alcohol intoxication (AI) cohort than in the non-AI cohort (12.2 vs. 3.43 per 10,000 person-years), with an adjusted HR (aHR) of 2.64 (95% CI = 2.26 to 3.08). This population-based study positively associated the event of alcohol intoxication with increased risk of liver abscess. Our findings warrant further large-scale and in-depth investigations in this area. Copyright © 2017 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.

Quasi-Experiments in Schools: The Case for Historical Cohort Control Groups

ERIC Educational Resources Information Center

Walser, Tamara M.

2014-01-01

There is increased emphasis on using experimental and quasi-experimental methods to evaluate educational programs; however, educational evaluators and school leaders are often faced with challenges when implementing such designs in educational settings. Use of a historical cohort control group design provides a viable option for conducting…

Cancer-related Imaging in the Veterans Affairs Health Care System versus Medicare: Does a System with Lower Use Exhibit Less Geographic Variation?

PubMed Central

McWilliams, J. Michael; Dalton, Jesse B.; Landrum, Mary Beth; Frakt, Austin B.; Pizer, Steven D.; Keating, Nancy L.

2014-01-01

Background Geographic variations in use of medical services have been interpreted as indirect evidence of wasteful care. Less overuse of services, however, may not be reliably associated with less geographic variation. Objective To compare average use and geographic variation in use of cancer-related imaging between fee-for-service Medicare and the Department of Veterans Affairs (VA) health care system. Design Observational analysis of cancer-related imaging from 2003–2005, using Medicare and VA utilization data linked to cancer registry data. We used multilevel models to estimate mean differences in annual imaging use between cohorts of Medicare and VA patients within geographic areas and variation in use across areas for each cohort, adjusting for sociodemographic and tumor characteristics. Setting 40 hospital referral regions. Patients Older men with lung, colorectal, or prostate cancer, including 34,475 traditional Medicare beneficiaries (Medicare cohort) and 6,835 VA patients (VA cohort). Measurements 1)Per-patient count of imaging studies for which lung, colorectal, or prostate cancer was the primary diagnosis (each study weighted by a standardized price); 2)a direct measure of overuse—advanced imaging for prostate cancer at low risk of metastasis. Results Adjusted annual use of cancer-related imaging was lower in the VA cohort than the Medicare cohort (price-weighted count, $197 vs. $379/patient; P<0.001), as was annual use of advanced imaging for prostate cancer at low risk of metastasis ($41 vs. $117/patient; P<0.001). Geographic variation in cancer-related imaging use was similar in magnitude in the VA and Medicare cohorts. Limitations Observational study design. Conclusions Use of cancer-related imaging was lower in the VA health care system than in fee-for-service Medicare, but lower use was not associated with less geographic variation. Geographic variation in service use may not be a reliable indicator of the extent of overuse. Primary Funding Source Doris Duke Charitable Foundation and Department of Veterans Affairs Office of Policy and Planning. PMID:25437407

Impact of Exercise Counseling on Physical Function in Chronic Kidney Disease: An Observational Study.

PubMed

Bohm, Clara J; Storsley, Leroy J; Hiebert, Brett M; Nelko, Serena; Tangri, Navdeep; Cheskin, Lawrence J; McAdams-DeMarco, Mara A; Rigatto, Claudio

2018-01-01

Individuals with chronic kidney disease (CKD) have low levels of physical activity and physical function. Although guidelines endorse exercise counseling for individuals with CKD, it is not yet part of routine care. We investigated the effect of attending a real-life exercise counseling clinic (ECC) on physical function in individuals with CKD. Retrospective analysis of prospectively collected observational data with quasi-experimental design. Patients with all stages of CKD registered in a large provincial renal program were eligible. The exposed cohort who attended the ECC between January 1, 2011, and March 15, 2014, included 214 individuals. The control cohort included 292 individuals enrolled in an observational study investigating longitudinal change in frailty during the same time period. Attendance at an ECC. Change in physical function as measured by Short Physical Performance Battery (SPPB) score, physical activity level (Human Activity Profile [HAP]/Physical Activity Scale for the Elderly [PASE]), and health-related quality of life (HRQOL; EQ5D/VAS) over 1 year. Eighty-seven individuals in the ECC cohort and 125 participants in the control cohort completed 1-year follow-up. Baseline median SPPB score was 10 (interquartile range [IQR]: 9-12) and 9 (IQR: 7-11) in the ECC and control cohorts, respectively ( P < .01). At 1 year, SPPB scores were 10 (IQR: 8-12) and 9 (IQR: 6-11) in the ECC and control cohorts, respectively ( P = .04). Mean change in SPPB over 1 year was not significantly different between groups: -0.33 (95% confidence interval [CI]: -0.81 to 0.15) in ECC and -0.22 (95% CI: -0.61 to 0.17) in control ( P = .72). There was no significant difference in the proportion of individuals in each cohort with an increase/decrease in SPPB score over time. There was no significant change in physical activity or HRQOL over time between groups. Quasi-experimental design, low rate of follow-up attendance. In this pragmatic study, exercise counseling had no significant effect on change in SPPB score, suggesting that a single exercise counseling session alone is inadequate to improve physical function in CKD.

Does educational status impact adult mortality in Denmark? A twin approach.

PubMed

Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

2010-07-15

To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921-1950 and followed during 1980-2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921-1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men.

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

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.

Apparently-Different Clearance Rates from Cohort Studies of Mycoplasma genitalium Are Consistent after Accounting for Incidence of Infection, Recurrent Infection, and Study Design.

PubMed

Smieszek, Timo; White, Peter J

2016-01-01

Mycoplasma genitalium is a potentially major cause of urethritis, cervicitis, pelvic inflammatory disease, infertility, and increased HIV risk. A better understanding of its natural history is crucial to informing control policy. Two extensive cohort studies (students in London, UK; Ugandan sex workers) suggest very different clearance rates; we aimed to understand the reasons and obtain improved estimates by making maximal use of the data from the studies. As M. genitalium is a sexually-transmitted infectious disease, we developed a model for time-to-event analysis that incorporates the processes of (re)infection and clearance, and fitted to data from the two cohort studies to estimate incidence and clearance rates under different scenarios of sexual partnership dynamics and study design (including sample handling and associated test sensitivity). In the London students, the estimated clearance rate is 0.80 p.a. (mean duration 15 months), with incidence 1.31%-3.93% p.a. Without adjusting for study design, corresponding estimates from the Ugandan data are 3.44 p.a. (mean duration 3.5 months) and 58% p.a. Apparent differences in clearance rates are probably mostly due to lower testing sensitivity in the Uganda study due to differences in sample handling, with 'true' clearance rates being similar, and adjusted incidence in Uganda being 28% p.a. Some differences are perhaps due to the sex workers having more-frequent antibiotic treatment, whilst reinfection within ongoing sexual partnerships might have caused some of the apparently-persistent infection in the London students. More information on partnership dynamics would inform more accurate estimates of natural-history parameters. Detailed studies in men are also required.

Impact of Study Design on Reported Incidences of Acute Mountain Sickness: A Systematic Review.

PubMed

Waeber, Baptiste; Kayser, Bengt; Dumont, Lionel; Lysakowski, Christopher; Tramèr, Martin R; Elia, Nadia

2015-09-01

Published incidences of acute mountain sickness (AMS) vary widely. Reasons for this variation, and predictive factors of AMS, are not well understood. We aimed to identify predictive factors that are associated with the occurrence of AMS, and to test the hypothesis that study design is an independent predictive factor of AMS incidence. We did a systematic search (Medline, bibliographies) for relevant articles in English or French, up to April 28, 2013. Studies of any design reporting on AMS incidence in humans without prophylaxis were selected. Data on incidence and potential predictive factors were extracted by two reviewers and crosschecked by four reviewers. Associations between predictive factors and AMS incidence were sought through bivariate and multivariate analyses for different study designs separately. Association between AMS incidence and study design was assessed using multiple linear regression. We extracted data from 53,603 subjects from 34 randomized controlled trials, 44 cohort studies, and 33 cross-sectional studies. In randomized trials, the median of AMS incidences without prophylaxis was 60% (range, 16%-100%); mode of ascent and population were significantly associated with AMS incidence. In cohort studies, the median of AMS incidences was 51% (0%-100%); geographical location was significantly associated with AMS incidence. In cross-sectional studies, the median of AMS incidences was 32% (0%-68%); mode of ascent and maximum altitude were significantly associated with AMS incidence. In a multivariate analysis, study design (p=0.012), mode of ascent (p=0.003), maximum altitude (p<0.001), population (p=0.002), and geographical location (p<0.001) were significantly associated with AMS incidence. Age, sex, speed of ascent, duration of exposure, or history of AMS were inconsistently reported and therefore not further analyzed. Reported incidences and identifiable predictive factors of AMS depend on study design.

Study design and hierarchy of evidence for surgical decision making.

PubMed

Sprague, Sheila; McKay, Paula; Thoma, Achilleas

2008-04-01

This article provides a historical overview of the hierarchy of evidence for surgical decision making and discusses key study designs in the hierarchy of evidence. This encompasses meta-analyses, randomized controlled trials, and observational studies, including cohort and case-controlled studies, case series and case reports, and basic science studies. This article also reviews the principles and importance of evidence-based plastic surgery and describes several systems to rate the strength of the scientific evidence.

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.

A trigger-based design for evaluating the safety of in utero antiretroviral exposure in uninfected children of human immunodeficiency virus-infected mothers.

PubMed

Williams, Paige L; Seage, George R; Van Dyke, Russell B; Siberry, George K; Griner, Raymond; Tassiopoulos, Katherine; Yildirim, Cenk; Read, Jennifer S; Huo, Yanling; Hazra, Rohan; Jacobson, Denise L; Mofenson, Lynne M; Rich, Kenneth

2012-05-01

The Pediatric HIV/AIDS Cohort Study's Surveillance Monitoring of ART Toxicities Study is a prospective cohort study conducted at 22 US sites between 2007 and 2011 that was designed to evaluate the safety of in utero antiretroviral drug exposure in children not infected with human immunodeficiency virus who were born to mothers who were infected. This ongoing study uses a "trigger-based" design; that is, initial assessments are conducted on all children, and only those meeting certain thresholds or "triggers" undergo more intensive evaluations to determine whether they have had an adverse event (AE). The authors present the estimated rates of AEs for each domain of interest in the Surveillance Monitoring of ART Toxicities Study. They also evaluated the efficiency of this trigger-based design for estimating AE rates and for testing associations between in utero exposures to antiretroviral drugs and AEs. The authors demonstrate that estimated AE rates from the trigger-based design are unbiased after correction for the sensitivity of the trigger for identifying AEs. Even without correcting for bias based on trigger sensitivity, the trigger approach is generally more efficient for estimating AE rates than is evaluating a random sample of the same size. Minor losses in efficiency when comparing AE rates between persons exposed and unexposed in utero to particular antiretroviral drugs or drug classes were observed under most scenarios.

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.

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.

Variation in Definition of Prolonged Mechanical Ventilation.

PubMed

Rose, Louise; McGinlay, Michael; Amin, Reshma; Burns, Karen Ea; Connolly, Bronwen; Hart, Nicholas; Jouvet, Philippe; Katz, Sherri; Leasa, David; Mawdsley, Cathy; McAuley, Danny F; Schultz, Marcus J; Blackwood, Bronagh

2017-10-01

Consistency of definitional criteria for terminology applied to describe subject cohorts receiving mechanical ventilation within ICU and post-acute care settings is important for understanding prevalence, risk stratification, effectiveness of interventions, and projections for resource allocation. Our objective was to quantify the application and definition of terms for prolonged mechanical ventilation. We conducted a scoping review of studies (all designs except single-case study) reporting a study population (adult and pediatric) using the term prolonged mechanical ventilation or a synonym. We screened 5,331 references, reviewed 539 full-text references, and excluded 120. Of the 419 studies (representing 38 countries) meeting inclusion criteria, 297 (71%) reported data on a heterogeneous subject cohort, and 66 (16%) included surgical subjects only (46 of those 66, 70% cardiac surgery). Other studies described COPD (16, 4%), trauma (22, 5%), neuromuscular (17, 4%), and sepsis (1, 0.2%) cohorts. A total of 741 terms were used to refer to the 419 study cohorts. The most common terms were: prolonged mechanical ventilation (253, 60%), admission to specialized unit (107, 26%), and long-term mechanical ventilation (79, 19%). Some authors (282, 67%) defined their cohorts based on duration of mechanical ventilation, with 154 studies (55%) using this as the sole criterion. We identified 37 different durations of ventilation ranging from 5 h to 1 y, with > 21 d being the most common (28 of 282, 7%). For studies describing a surgical cohort, minimum ventilation duration required for inclusion was ≥ 24 h for 20 of 66 studies (30%). More than half of all studies (237, 57%) did not provide a reason/rationale for definitional criteria used, with only 28 studies (7%) referring to a consensus definition. We conclude that substantial variation exists in the terminology and definitional criteria for cohorts of subjects receiving prolonged mechanical ventilation. Standardization of terminology and definitional criteria is required for study data to be maximally informative. Copyright © 2017 by Daedalus Enterprises.

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

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

Chinese college freshmen's mental health problems and their subsequent help-seeking behaviors: A cohort design (2005-2011).

PubMed

Liu, Fenge; Zhou, Nan; Cao, Hongjian; Fang, Xiaoyi; Deng, Linyuan; Chen, Wenrui; Lin, Xiuyun; Liu, Lu; Zhao, Huichun

2017-01-01

Based on cohort data obtained from 13,085 college freshmen's (2005 to 2011) SCL-90 (the Symptom Check-List-90) reports and their subsequent 4-year psychological counseling help-seeking records, this study examined the association between college students' mental health problems and help-seeking behaviors across four college years. Female students' mental health problems and help-seeking behaviors increased from the 2005 to the 2011 cohorts and no changes emerged for male students across cohorts. Overall, male students reported higher levels of mental health problems than did female students in the first college year, whereas female students reported more help-seeking behaviors than did male students in the following four college years. College students' mental health problems was associated positively with help-seeking behaviors. College students were more likely to seek help from the college psychological counselling center when they experienced relatively few or quite a lot of mental health issues (i.e., an inversed U shape). Implications for future studies and practices are discussed.

Progression to insulin for patients with diabetes mellitus on dual oral antidiabetic therapy using the US Department of Defense Database.

PubMed

Rascati, K; Richards, K; Lopez, D; Cheng, L-I; Wilson, J

2013-10-01

To compare 'progression to insulin' for three cohorts on oral antidiabetic medication combinations: metformin/sulphonylurea (Met/SU), metformin/thiazolidinedione (Met/TZD) and sulphonylurea/thiazolidinedione (SU/TZD). Retrospective cohort analysis design was used. The subjects were US nationwide members of military and their families. A total of 5608 patients who were on antidiabetic monotherapy for at least 1 year before adding a second agent to their medication regimen between October 2001 and September 2008 participated in this study. Mean age ranged from 64 to 71 years among the cohorts. Cox regression compared the progression to insulin, adjusting for demographics, months of follow-up and co-morbidities [measured with Chronic Disease Score (CDS)]. By the end of the 2- to 6-year follow-up period, 14.3% of the Met/TZD cohort, 23.6% of the Met/SU cohort and 28.2% of the SU/TZD cohort had insulin added to their regimen. Those in the Met/SU cohort had a 1.8 times higher probability of progression to insulin than those in the Met/TZD cohort [odds ratio (OR) = 1.80, 95% confidence interval (CI) = 1.51-2.14), and those in the SU/TZD cohort had a 2.5 times higher probability of progression to insulin than those in the Met/TZD cohort (OR = 2.51, 95% CI = 2.04-3.08). When sensitizers were paired (Met/TZD), a lower percentage of patients progressed to insulin during the study period, as opposed to patients who used a combination of a secretagogue with a sensitizer (SU/TZD or Met/SU). © 2013 John Wiley & Sons Ltd.

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...

Multicenter AIDS Cohort Study Quantitative Coronary Plaque Progression Study: rationale and design.

PubMed

Nakanishi, Rine; Post, Wendy S; Osawa, Kazuhiro; Jayawardena, Eranthi; Kim, Michael; Sheidaee, Nasim; Nezarat, Negin; Rahmani, Sina; Kim, Nicholas; Hathiramani, Nicolai; Susarla, Shriraj; Palella, Frank; Witt, Mallory; Blaha, Michael J; Brown, Todd T; Kingsley, Lawrence; Haberlen, Sabina A; Dailing, Christopher; Budoff, Matthew J

2018-01-01

The association of HIV with coronary atherosclerosis has been established; however, the progression of coronary atherosclerosis over time among participants with HIV is not well known. The Multicenter AIDS Cohort Study Quantitative Coronary Plaque Progression Study is a large prospective multicenter study quantifying progression of coronary plaque assessed by serial coronary computed tomography angiography (CTA). HIV-infected and uninfected men who were enrolled in the Multicenter AIDS Cohort Study Cardiovascular Substudy were eligible to complete a follow-up contrast coronary CTA 3-6 years after baseline. We measured coronary plaque volume and characteristics (calcified and noncalcified plaque including fibrous, fibrous-fatty, and low attenuation) and vulnerable plaque among HIV-infected and uninfected men using semiautomated plaque software to investigate the progression of coronary atherosclerosis over time. We describe a novel, large prospective multicenter study investigating incidence, transition of characteristics, and progression in coronary atherosclerosis quantitatively assessed by serial coronary CTAs among HIV-infected and uninfected men.

Dinitrotoluene exposure in the copper mining industry and renal cancer: a case-cohort study.

PubMed

Seidler, Andreas; Harth, Volker; Taeger, Dirk; Möhner, Matthias; Gawrych, Katarzyna; Bergmann, Annekatrin; Haerting, Johannes; Kahmann, Hans-Joachim; Bolt, Hermann Maximilian; Straif, Kurt; Brüning, Thomas

2014-04-01

To evaluate the association between dinitrotoluene (DNT) exposure and renal cancer in a case-cohort study. This case-cohort study was conducted among men born between 1920 and 1974 (n=16 441) who were gainfully employed between 1953 and 1990 in one of two copper mines in Mansfeld, Saxony-Anhalt, former German Democratic Republic, and followed up till 31 December 2006. The study included 109 cases with renal cancer identified by record linkage with the Common Cancer Registry of the New Federal States of Germany (GKR) or by a network of pathology institutes. A comparison subcohort of 999 cohort members was selected at random from the total cohort. Duration and intensity of inhalation and dermal exposure to DNT were assessed on the basis of a job exposure matrix. A time-dependent Cox proportional hazards model modified for case-cohort design was used to assess the relationship between cumulative inhalation and dermal DNT exposure and renal cancer. Elevated risks were found for medium (HR=2.73; 95% CI 1.00 to 7.42) and high (HR=1.81; 95% CI 0.75 to 4.33) dermal exposure to DNT. Relative risks for medium inhalation exposure to DNT were not increased (HR=0.93; 95% CI 0.48 to 1.79) while relative risks for high inhalation exposure to DNT were elevated to 1.36 (95% CI 0.84 to 2.21). We found a statistically significant HR of 2.12 (95% CI 1.03 to 4.37) for combined medium or high inhalation and medium or high dermal exposure to DNT. According to our case-cohort study, dermal and inhalation exposure to DNT is associated with increased renal cancer risk.

An innovation in curriculum content and delivery of cancer education within undergraduate nurse training in the UK. What impact does this have on the knowledge, attitudes and confidence in delivering cancer care?

PubMed

Edwards, Deborah; Anstey, Sally; Kelly, Daniel; Hopkinson, Jane

2016-04-01

This was an evaluation of an innovation in curriculum content and delivery within undergraduate nursing education in the UK. Its purpose was to investigate the effect on knowledge, attitudes and confidence in delivering cancer care. The study design was a pre-test post-test survey design with a comparison group. Participants were two cohorts of undergraduate nursing students (n(intervention) = 84, n(comparison) = 91). The intervention cohort were exposed to a new 3.5 day programme of cancer education, coproduced with patients, carers and health professionals, which focused on cancer as a life changing long-term condition. The comparison cohort had been exposed to a 2 day programme produced by a lecturer. Following exposure to the new model for the delivery of undergraduate nurse cancer education, the intervention cohort demonstrated good overall knowledge of the impact of cancer, more positive attitudes towards cancer treatment and more confidence in their ability to deliver cancer care. Attitudes were more positive and confidence in ability to support cancer patients at all stages of the cancer journey were greater than in the comparison group. Insights gained into the cancer patient and carer perspectives were highly valued. This study has found that a new model for the delivery of cancer education focusing on survivorship and delivered in partnership with patients, carers and clinicians, may improve knowledge, attitudes and confidence in the delivery of cancer care. Further work is now needed, using a more robust experimental design, to investigate the generalisability of the results to other education programs. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

Effect of technological advances on cochlear implant performance in adults.

PubMed

Lenarz, Minoo; Joseph, Gert; Sönmez, Hasibe; Büchner, Andreas; Lenarz, Thomas

2011-12-01

To evaluate the effect of technological advances in the past 20 years on the hearing performance of a large cohort of adult cochlear implant (CI) patients. Individual, retrospective, cohort study. According to technological developments in electrode design and speech-processing strategies, we defined five virtual intervals on the time scale between 1984 and 2008. A cohort of 1,005 postlingually deafened adults was selected for this study, and their hearing performance with a CI was evaluated retrospectively according to these five technological intervals. The test battery was composed of four standard German speech tests: Freiburger monosyllabic test, speech tracking test, Hochmair-Schulz-Moser (HSM) sentence test in quiet, and HSM sentence test in 10 dB noise. The direct comparison of the speech perception in postlingually deafened adults, who were implanted during different technological periods, reveals an obvious improvement in the speech perception in patients who benefited from the recent electrode designs and speech-processing strategies. The major influence of technological advances on CI performance seems to be on speech perception in noise. Better speech perception in noisy surroundings is strong proof for demonstrating the success rate of new electrode designs and speech-processing strategies. Standard (internationally comparable) speech tests in noise should become an obligatory part of the postoperative test battery for adult CI patients. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Cohort Study of Severe Bronchiolitis during Infancy and Risk of Asthma by Age 5 Years.

PubMed

Balekian, Diana S; Linnemann, Rachel W; Hasegawa, Kohei; Thadhani, Ravi; Camargo, Carlos A

Severe bronchiolitis (ie, bronchiolitis requiring hospital admission) is thought to markedly increase asthma risk, with 30%-50% developing asthma by age 5 years. To date, studies of this association are small, and most are from outside the United States. The objective of this study was to investigate the association between severe bronchiolitis and risk of asthma in a US birth cohort. We studied a cohort nested within the Massachusetts General Hospital Obstetric Maternal Study (MOMS), a prospective cohort of pregnant women enrolled during 1998-2006. Children of mothers enrolled in MOMS were included in the analysis if they received care within our health system (n = 3653). Diagnoses and medications were extracted from the children's electronic health records; we also examined pregnancy and perinatal risk factors collected for the underlying pregnancy study. The birth cohort was 52% male, 49% white, and 105 infants (2.9%) had severe bronchiolitis. Overall, 421 children (11.5%) developed asthma by age 5 years. Among the children with severe bronchiolitis, 27.6% developed asthma by age 5 years. In multivariable logistic regression adjusting for 12 risk factors, severe bronchiolitis remained a strong risk factor for developing asthma by age 5 years (odds ratio 2.57; 95% confidence interval 1.61-4.09). In a large Boston birth cohort, the frequency of severe bronchiolitis and childhood asthma was similar to published data. Among children with severe bronchiolitis, the risk of developing asthma was lower than prior studies but still high (27.6%). This difference may be due to different study designs, populations, and outcome definitions studied. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

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.

DEMONSTRATION OF LOW COST, LOW BURDEN EXPOSURE MONITORING STRATEGIES - BIRTH COHORT

EPA Science Inventory

This study was designed to develop and demonstrate relevant, low cost, low burden monitoring strategies that can be used in a longitudinal epidemiological study that focuses on pregnant women and young children. The focus of this study was on (1) recruiting and retaining partici...

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.

Cognitive performance in childhood and early adult illness: a prospective cohort study

PubMed Central

Martin, L.; Fitzmaurice, G.; Kindlon, D.; Buka, S.

2004-01-01

Study objective: To evaluate whether cognitive performance in childhood is an early determinant of adult illness. Design: Prospective cohort study covering over 30 years. Setting: Providence, Rhode Island, USA. Participants: 633 people ages 30–39 followed up since birth as part of the Providence cohort of the national collaborative perinatal project. Main results: Higher cognitive performance at age 7 was related to a significantly reduced risk of serious illness in adulthood, OR = 0.65 (95%CI: 0.47 to 0.89) for a one standard deviation (15 point) increase in IQ score. This association was independent of both parental socioeconomic status and participant's attained level of education. Conclusions: General cognitive performance may be an important and informative early determinant of adult health. Further evaluation of this association and mechanisms linking cognitive performance and health may provide new and innovative strategies to improve disease management and reduce morbidity. PMID:15252070

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

Student Mobility, Dosage, and Principal Stratification in School-Based RCTs

ERIC Educational Resources Information Center

Schochet, Peter Z.

2013-01-01

In school-based randomized control trials (RCTs), a common design is to follow student cohorts over time. For such designs, education researchers usually focus on the place-based (PB) impact parameter, which is estimated using data collected on all students enrolled in the study schools at each data collection point. A potential problem with this…

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…

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

Gender and psychosocial factors associated with healthy lifestyle in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort: a cross-sectional study

PubMed Central

Patrão, Ana Luísa; Almeida, Maria da Conceição; Matos, Sheila Maria Alvim; Chor, Dora; Aquino, Estela M. L.

2017-01-01

Objectives It has been estimated that over 50% of the premature deaths occurring in Western countries can be attributed to causes rooted in lifestyle. In turn, leading a healthy lifestyle has also been associated with a wide range of psychosocial factors. Today, it is known that these differ among men and women. The present article aimed to identify, from a gender-based perspective, the psychosocial factors associated with healthy lifestyles in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort, the largest study concerning adult health conducted in Latin America to date. Design This cross-sectional study was conducted using ELSA-Brasil baseline data, collected between 2008 and 2010. Setting Six Brazilian public higher education and research institutions. Participants The ELSA-Brasil cohort consists of approximately 15 000 employees (8218 women and 6887 men), both currently working and retired. Main outcome measures The lifestyle indicator was constructed by summing the scores attributed to four different behaviours. Results The women of the ELSA-Brasil cohort have healthier lifestyles than men. In women, strong associations were found between a healthy lifestyle and age 60 years or older, Asian race and university level of education or higher. In men, being 60 years or older, of Asian or Caucasian race, having a high-school equivalent level of education or higher, being retired, having a housekeeper, having a good or very good self-perception of health and being satisfied with body image were the psychosocial factors associated with leading a healthy lifestyle. Conclusions The factors that influenced healthy lifestyles were found to differ among men and women, a fact that must be addressed when developing programmes designed to promote health. PMID:28851775

Risk of acute liver injury associated with use of antibiotics. Comparative cohort and nested case-control studies using two primary care databases in Europe.

PubMed

Brauer, Ruth; Douglas, Ian; Garcia Rodriguez, Luis Alberto; Downey, Gerald; Huerta, Consuelo; de Abajo, Francisco; Bate, Andrew; Feudjo Tepie, Maurille; de Groot, Mark C H; Schlienger, Raymond; Reynolds, Robert; Smeeth, Liam; Klungel, Olaf; Ruigómez, Ana

2016-03-01

To assess the impact of varying study designs, exposure and outcome definitions on the risk of acute liver injury (ALI) associated with antibiotic use. The source population comprised of patients registered in two primary care databases, in the UK and in Spain. We identified a cohort consisting of new users of antibiotics during the study period (2004-2009) and non-users during the study period or in the previous year. Cases with ALI were identified within this cohort and classified as definite or probable, based on recorded medical information. The relative risk (RR) of ALI associated with antibiotic use was computed using Poisson regression. For the nested case-control analyses, up to five controls were matched to each case by age, sex, date and practice (in CPRD) and odds ratios (OR) were computed with conditional logistic regression. The age, sex and year adjusted RRs of definite ALI in the current antibiotic use periods was 10.04 (95% CI: 6.97-14.47) in CPRD and 5.76 (95% CI: 3.46-9.59) in BIFAP. In the case-control analyses adjusting for life-style, comorbidities and use of medications, the OR of ALI for current users of antibiotics was and 5.7 (95% CI: 3.46-9.36) in CPRD and 2.6 (95% CI: 1.26-5.37) in BIFAP. Guided by a common protocol, both cohort and case-control study designs found an increased risk of ALI associated with the use of antibiotics in both databases, independent of the exposure and case definitions used. However, the magnitude of the risk was higher in CPRD compared to BIFAP. Copyright © 2016 John Wiley & Sons, Ltd.

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.

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.

On the confounds among retest gains and age-cohort differences in the estimation of within-person change in longitudinal studies: a simulation study.

PubMed

Hoffman, Lesa; Hofer, Scott M; Sliwinski, Martin J

2011-12-01

Although longitudinal designs are the only way in which age changes can be directly observed, a recurrent criticism involves to what extent retest effects may downwardly bias estimates of true age-related cognitive change. Considerable attention has been given to the problem of retest effects within mixed effects models that include separate parameters for longitudinal change over time (usually specified as a function of age) and for the impact of retest (specified as a function of number of exposures). Because time (i.e., intervals between assessment) and number of exposures are highly correlated (and are perfectly correlated in equal interval designs) in most longitudinal studies, the separation of effects of within-person change from effects of retest gains is only possible given certain assumptions (e.g., age convergence). To the extent that cross-sectional and longitudinal effects of age differ, obtained estimates of aging and retest may not be informative. The current simulation study investigated the recovery of within-person change (i.e., aging) and retest effects from repeated cognitive testing as a function of number of waves, age range at baseline, and size and direction of age-cohort differences on the intercept and age slope in age-based models of change. Significant bias and Type I error rates in the estimated effects of retest were observed when these convergence assumptions were not met. These simulation results suggest that retest effects may not be distinguishable from effects of aging-related change and age-cohort differences in typical long-term traditional longitudinal designs.

Embedding clinical interventions into observational studies

PubMed Central

Newman, Anne B.; Avilés-Santa, M. Larissa; Anderson, Garnet; Heiss, Gerardo; Howard, Wm. James; Krucoff, Mitchell; Kuller, Lewis H.; Lewis, Cora E.; Robinson, Jennifer G.; Taylor, Herman; Treviño, Roberto P.; Weintraub, William

2017-01-01

Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed. PMID:26611435

Birth cohorts in asthma and allergic diseases: Report of a NIAID, NHLBI, MeDALL joint workshop

PubMed Central

Bousquet, J; Gern, JE; Martinez, FD; Anto, JM; Johnson, CC; Holt, PG; Lemanske, RF; Le Souef, PN; Tepper, R; von Mutius, ERM; Arshad, SH; Bacharier, LB; Becker, A; Belanger, K; Bergstrom, A; Bernstein, D; Cabana, MD; Carroll, KN; Castro, M; Cooper, PJ; Gillman, MW; Gold, DR; Henderson, J; Heinrich, J; S-J, Hong; Jackson, DJ; Keil, T; Kozyrskyj, AL; Lodrup-Carlsen, K; Miller, RL; Momas, I; Morgan, WJ; Noel, P; Ownby, DR; Pinart, M; Ryan, P; Schwaninger, JM; Sears, MR; Simpson, A; Smit, HA; Stern, D; Subbarao, P; Valenta, R; Wang, X; Weiss, ST; Wood, R; Wright, AL; Wright, RJ; Togias, A; Gergen, PJ

2014-01-01

Population-based birth cohorts on asthma and allergies increasingly provide new insights into the development and natural history of the diseases. Over 130 birth cohorts focusing on asthma and allergy have been initiated in the last 30 years. A NIAID (National Institute of Allergy and Infectious Diseases), NHLBI (National Heart Lung and Blood Institute), MeDALL (Mechanisms of the Development of Allergy, Framework Programme 7 of the European Commission) joint workshop was held in Bethesda, MD, USA September 11–12, 2012 with 3 objectives (1) documenting the knowledge that asthma/allergy birth cohorts have provided, (2) identifying the knowledge gaps and inconsistencies and (3) developing strategies for moving forward, including potential new study designs and the harmonization of existing asthma birth cohort data. The meeting was organized around the presentations of 5 distinct workgroups: (1) clinical phenotypes, (2) risk factors, (3) immune development of asthma and allergy, (4) pulmonary development and (5) harmonization of existing birth cohorts. This manuscript presents the workgroup reports and provides web links (AsthmaBirthCohorts.niaid.nih.gov or www.medall-fp7.eu) where the reader will find tables describing the characteristics of the birth cohorts included in this report, type of data collected at differing ages, and a selected bibliography provided by the participating birth cohorts. PMID:24636091

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.

The Coordination and Activity Tracking in CHildren (CATCH) study: rationale and design.

PubMed

Cairney, John; Missiuna, Cheryl; Timmons, Brian W; Rodriguez, Christine; Veldhuizen, Scott; King-Dowling, Sara; Wellman, Sarah; Le, Tuyen

2015-12-21

Past studies have found that children with Developmental Coordination Disorder (DCD) engage in less physical activity than typically developing children. This "activity deficit" may result in children with DCD being less physically fit and more likely to be overweight or obese, potentially increasing later risk for poor cardiovascular health. Unfortunately, the majority of DCD research has been limited to cross-sectional designs, leading to questions about the complex relationship among motor ability, inactivity and health-related fitness. Of the few longitudinal studies on the topic, determining precedence amongst these factors is difficult because study cohorts typically focus on mid to late childhood. By this age, both decreased physical fitness and obesity are often established. The Coordination and Activity Tracking in CHildren (CATCH) study will examine the pathways connecting DCD, physical activity, physical fitness, and body composition from early to middle childhood. The CATCH study is a prospective cohort study. We aim to recruit a cohort of 600 children aged 4 to 5 years (300 probable DCD [pDCD] and 300 controls) and test them once a year for 4 years. At Phase 1 of baseline testing, we assess motor skills, cognitive ability (IQ), basic anthropometry, flexibility and lower body muscle strength, while parents complete an interview and questionnaires regarding family demographics, their child's physical activity, and behavioural characteristics. Children who move on to Phase 2 (longitudinal cohort) have their body fat percentage, foot structure, aerobic and anaerobic fitness assessed. An accelerometer to measure physical activity is then given to the child and interested family members. The family also receives an accelerometer logbook and 3-day food dairy. At years 2 to 4, children in the longitudinal cohort will have all baseline assessments repeated (excluding the IQ test), and complete an additional measure of perceived self-efficacy. Parents will complete an ADHD index twice within the follow-up period. To assess the association between DCD, fitness and adiposity, our primary analysis will involve longitudinal growth models with fixed effects. The CATCH study will provide a clearer understanding of pathways between DCD and health-related fitness necessary to determine the types of interventions children with DCD require.

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

Cohort Profile: Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) prospective cohort study.

PubMed

Malan, Leoné; Hamer, Mark; Frasure-Smith, Nancy; Steyn, Hendrik S; Malan, Nicolaas T

2015-12-01

Adapting to an over-demanding stressful urban environment may exhaust the psychophysiological resources to cope with these demands, and lead to sympathetic nervous system dysfunction. The evidence that an urban-dwelling lifestyle may be detrimental to the cardiometabolic health of Africans motivated the design of the Sympathetic activity and Ambulatory Blood Pressure in African Prospective cohort study. We aimed to determine neural mechanistic pathways involved in emotional distress and vascular remodelling. The baseline sample included 409 teachers representing a bi-ethnic sex cohort from South Africa. The study was conducted in 2008-09 and repeated after 3-year follow-up in 2011-12, with an 87.8% successful follow-up rate. Seasonal changes were avoided and extensive clinical assessments were performed in a well-controlled setting. Data collection included sociodemographics, lifestyle habits, psychosocial battery and genetic analysis, mental stress responses mimicking daily life stress (blood pressure and haemostatic, cardiometabolic, endothelial and stress hormones). Target organ damage was assessed in the brain, heart, kidney, blood vessels and retina. A unique highly phenotyped cohort is presented that can address the role of a hyperactive sympathetic nervous system and neural response pathways contributing to the burden of cardiometabolic diseases in Africans. © The Author 2014. Published by Oxford University Press on behalf of the International Epidemiological Association.

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

CAPR - Theresa Guerin | Center for Cancer Research

Cancer.gov

Theresa Guerin oversees animal colony management and provides support in breeding experimental animal cohort, preparing documentation for CAPR preclinical studies, as well as assistance in designing drug treatment plans. She also maintains multiple database resources. Expertise

HARVARD PARTICLE CENTER

EPA Science Inventory

The Center encompassed four highly interdisciplinary and integrated projects designed to address the four scientific questions presented above. Project 1 investigated the health effects of PM in the Normative Aging Study cohort, in Eastern Massachusetts; 

International trends in clozapine use: a study in 17 countries.

PubMed

Bachmann, C J; Aagaard, L; Bernardo, M; Brandt, L; Cartabia, M; Clavenna, A; Coma Fusté, A; Furu, K; Garuoliené, K; Hoffmann, F; Hollingworth, S; Huybrechts, K F; Kalverdijk, L J; Kawakami, K; Kieler, H; Kinoshita, T; López, S C; Machado-Alba, J E; Machado-Duque, M E; Mahesri, M; Nishtala, P S; Piovani, D; Reutfors, J; Saastamoinen, L K; Sato, I; Schuiling-Veninga, C C M; Shyu, Y-C; Siskind, D; Skurtveit, S; Verdoux, H; Wang, L-J; Zara Yahni, C; Zoëga, H; Taylor, D

2017-07-01

There is some evidence that clozapine is significantly underutilised. Also, clozapine use is thought to vary by country, but so far no international study has assessed trends in clozapine prescribing. Therefore, this study aimed to assess clozapine use trends on an international scale, using standardised criteria for data analysis. A repeated cross-sectional design was applied to data extracts (2005-2014) from 17 countries worldwide. In 2014, overall clozapine use prevalence was greatest in Finland (189.2/100 000 persons) and in New Zealand (116.3/100 000), and lowest in the Japanese cohort (0.6/100 000), and in the privately insured US cohort (14.0/100 000). From 2005 to 2014, clozapine use increased in almost all studied countries (relative increase: 7.8-197.2%). In most countries, clozapine use was highest in 40-59-year-olds (range: 0.6/100 000 (Japan) to 344.8/100 000 (Finland)). In youths (10-19 years), clozapine use was highest in Finland (24.7/100 000) and in the publicly insured US cohort (15.5/100 000). While clozapine use has increased in most studied countries over recent years, clozapine is still underutilised in many countries, with clozapine utilisation patterns differing significantly between countries. Future research should address the implementation of interventions designed to facilitate increased clozapine utilisation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dietary flavonoid intake and the risk of stroke: a dose-response meta-analysis of prospective cohort studies

PubMed Central

Tang, Zhenyu; Li, Min; Zhang, Xiaowei; Hou, Wenshang

2016-01-01

Objective To clarify and quantify the potential association between intake of flavonoids and risk of stroke. Design Meta-analysis of prospective cohort studies. Data source Studies published before January 2016 identified through electronic searches using PubMed, Embase and the Cochrane Library. Eligibility criteria for selecting studies Prospective cohort studies with relative risks and 95% CIs for stroke according to intake of flavonoids (assessed as dietary intake). Results The meta-analysis yielded 11 prospective cohort studies involving 356 627 participants and more than 5154 stroke cases. The pooled estimate of the multivariate relative risk of stroke for the highest compared with the lowest dietary flavonoid intake was 0.89 (95% CI 0.82 to 0.97; p=0.006). Dose-response analysis indicated that the summary relative risk of stroke for an increase of 100 mg flavonoids consumed per day was 0.91 (95% CI 0.77 to 1.08) without heterogeneity among studies (I2=0%). Stratifying by follow-up duration, the relative risk of stroke for flavonoid intake was 0.89 (95% CI 0.81 to 0.99) in studies with more than 10 years of follow-up. Conclusions Results from this meta-analysis suggest that higher dietary flavonoid intake may moderately lower the risk of stroke. PMID:27279473

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...

Intensive mode delivery of a neuroanatomy unit: lower final grades but higher student satisfaction.

PubMed

Whillier, Stephney; Lystad, Reidar P

2013-01-01

In 2011, Macquarie University moved to a three-session academic year which included two 13-week sessions (traditional mode) and one seven-week session (intensive mode). This study was designed to compare the intensive and traditional modes of delivery in a unit of undergraduate neuroanatomy. The new intensive mode neuroanatomy unit provided the same quantity and quality of material to the same standard, delivered by the same teachers and over the same total hours, but in a shorter timeframe. All students enrolled in session 2 (traditional mode) and session 3 (intensive mode) were invited to participate in this study. The main outcome measures were the final course grades and level of satisfaction with the course. Although there was no significant difference between the two cohorts in self-rated level of knowledge (P = 0.148), the traditional mode cohort achieved significantly higher final grades compared to the intensive mode cohort (P = 0.001). Similarly, the distribution of final grades was also different between the two cohorts. The two cohorts were equally satisfied with the unit overall, and with the lectures and tutorials. However, the intensive mode cohort was more satisfied with the laboratory practical classes compared to the traditional mode cohort (P < 0.001). Thus this study demonstrates that in the case of neuroanatomy, which is high in content, when the course is taught to the same standards as exist in the traditional mode of delivery, the students do not do as well even though they enjoy the course equally. Copyright © 2013 American Association of Anatomists.

The UAE healthy future study: a pilot for a prospective cohort study of 20,000 United Arab Emirates nationals.

PubMed

Abdulle, Abdishakur; Alnaeemi, Abdullah; Aljunaibi, Abdullah; Al Ali, Abdulrahman; Al Saedi, Khaled; Al Zaabi, Eiman; Oumeziane, Naima; Al Bastaki, Marina; Al-Houqani, Mohammed; Al Maskari, Fatma; Al Dhaheri, Ayesha; Shah, Syed M; Loney, Tom; El-Sadig, Mohamed; Oulhaj, Abderrahim; Wareth, Leila Abdel; Al Mahmeed, Wael; Alsafar, Habiba; Hirsch, Benjamin; Al Anouti, Fatme; Yaaqoub, Jamila; Inman, Claire K; Al Hamiz, Aisha; Al Hosani, Ayesha; Haji, Muna; Alsharid, Teeb; Al Zaabi, Thekra; Al Maisary, Fatima; Galani, Divya; Sprosen, Tim; El Shahawy, Omar; Ahn, Jiyoung; Kirchhoff, Tomas; Ramasamy, Ravichandran; Schmidt, Ann Marie; Hayes, Richard; Sherman, Scott; Ali, Raghib

2018-01-05

The United Arab Emirates (UAE) is faced with a rapidly increasing burden of non-communicable diseases including obesity, diabetes, and cardiovascular disease. The UAE Healthy Future study is a prospective cohort designed to identify associations between risk factors and these diseases amongst Emiratis. The study will enroll 20,000 UAE nationals aged ≥18 years. Environmental and genetic risk factors will be characterized and participants will be followed for future disease events. As this was the first time a prospective cohort study was being planned in the UAE, a pilot study was conducted in 2015 with the primary aim of establishing the feasibility of conducting the study. Other objectives were to evaluate the implementation of the main study protocols, and to build adequate capacity to conduct advanced clinical laboratory analyses. Seven hundred sixty nine UAE nationals aged ≥18 years were invited to participate voluntarily in the pilot study. Participants signed an informed consent, completed a detailed questionnaire, provided random blood, urine, and mouthwash samples and were assessed for a series of clinical measures. All specimens were transported to the New York University Abu Dhabi laboratories where samples were processed and analyzed for routine chemistry and hematology. Plasma, serum, and a small whole blood sample for DNA extraction were aliquoted and stored at -80 °C for future analyses. Overall, 517 Emirati men and women agreed to participate (68% response rate). Of the total participants, 495 (95.0%), 430 (82.2%), and 492 (94.4%), completed the questionnaire, physical measurements, and provided biological samples, respectively. The pilot study demonstrated the feasibility of recruitment and completion of the study protocols for the first large-scale cohort study designed to identify emerging risk factors for the major non-communicable diseases in the region.

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

Long-term dietary sodium, potassium and fluid intake; exploring potential novel risk factors for renal cell cancer in the Netherlands Cohort Study on diet and cancer.

PubMed

Deckers, I A G; van den Brandt, P A; van Engeland, M; Soetekouw, P M M B; Baldewijns, M M L L; Goldbohm, R A; Schouten, L J

2014-02-04

As sodium, potassium and fluid intake are related to hypertension, an established risk factor for renal cell cancer (RCC), they may be independent risk factors for RCC. The Netherlands Cohort Study (NLCS) with case-cohort design included 120,852 participants aged 55-69 years. At baseline, diet and lifestyle were assessed with questionnaires. After 17.3 years of follow-up, 485 RCC cases and 4438 subcohort members were available for analyses. Sodium intake increased RCC risk (P-trend=0.03), whereas fluid and potassium intake did not. For high sodium and low fluid intake, the RCC risk additionally increased (P-interaction=0.02). Sodium intake is a potential risk factor for RCC, particularly if fluid consumption is low.

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.

Longevity of anterior resin-bonded bridges: survival rates of two tooth preparation designs.

PubMed

Abuzar, M; Locke, J; Burt, G; Clausen, G; Escobar, K

2018-04-16

Significant developments have occurred in the design of resin-bonded bridges (RBB) over the past two decades. They are commonly used as an alternative treatment option for a single missing tooth. The longevity of these bridges needs to be further investigated to evaluate long-term outcomes for this option to remain relevant. A cohort of patients who received anterior resin-bonded bridges (ARBB) over two decades was studied retrospectively. Longevity of 206 ARBB was assessed using Kaplan-Meier probability estimates. The two modified tooth preparation designs investigated were: (A) mesial and distal vertical grooves only; and (B) one proximal groove adjacent to the pontic and two palatal grooves. Age and gender of the patient cohort were also recorded. Overall survival rate of ARBB was 98% at 5 years, 97.2% at 10 years, and 95.1% from 12 years till 21 years. Survival curves showed minor differences when compared for the two designs, age groups and gender of ARBB recipients. Differences in the proportion of surviving bridges for design A (95.96%) and design B (98.13%) were not statistically significant (Fisher's exact test). Anterior RBB with described tooth preparation designs demonstrate a high survival rate. © 2018 Australian Dental Association.

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.

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.

IN UTERO ENVIRONMENTAL EXPOSURES IN THE NATIONAL CHILDREN'S STUDY - MEASUREMENT STRATEGIES

EPA Science Inventory

The National Children¿s Study (NCS) is a longitudinal cohort study which is designed to follow a nationally representative sample of American children from prior to conception or early pregnancy until age 21 years. The Children's Health Act of 2000 directs a consortium of United...

Associations between anthropometric characteristics, physical activity, and breast cancer risk in a Canadian cohort.

PubMed

Catsburg, Chelsea; Kirsh, Victoria A; Soskolne, Colin L; Kreiger, Nancy; Bruce, Erin; Ho, Thi; Leatherdale, Scott T; Rohan, Thomas E

2014-06-01

Obesity, physical inactivity, and sedentary behavior, concomitants of the modern environment, are potentially modifiable breast cancer risk factors. This study investigated the association of anthropometric measurements, physical activity and sedentary behavior, with the risk of incident, invasive breast cancer using a prospective cohort of women enrolled in the Canadian Study of Diet, Lifestyle and Health. Using a case-cohort design, an age-stratified subcohort of 3,320 women was created from 39,532 female participants who returned completed self-administered lifestyle and dietary questionnaires at baseline. A total of 1,097 incident breast cancer cases were identified from the entire cohort via linkage to the Canadian Cancer Registry. Cox regression models, modified to account for the case-cohort design, were used to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for the association between anthropometric characteristics, physical activity, and the risk of breast cancer. Weight gain as an adult was positively associated with risk of post-menopausal breast cancer, with a 6 % increase in risk for every 5 kg gained since age 20 (HR 1.06; 95 % CI 1.01-1.11). Women who exercised more than 30.9 metabolic equivalent task (MET) hours per week had a 21 % decreased risk of breast cancer compared to women who exercised less than 3 MET hours per week (HR  0.79; 95 % CI 0.62-1.00), most evident in pre-menopausal women (HR  0.62; 95 % CI 0.43-0.90). As obesity reaches epidemic proportions and sedentary lifestyles have become more prevalent in modern populations, programs targeting adult weight gain and promoting physical activity may be beneficial with respect to reducing breast cancer morbidity.

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

Preservice Teacher Talk Surrounding Gender

ERIC Educational Resources Information Center

Engebretson, Kathryn Ellerhoff

2012-01-01

This dissertation examines the discourses around gender present among a cohort of preservice secondary social studies teachers (n = 25) and how gender discourses manifested throughout their preparatory year with particular interest paid to their thoughts about curricula, schools, and students. Using ethnographic study design, the author presents…

Realization of entry-to-practice milestones by Canadians who studied medicine abroad and other international medical graduates: a retrospective cohort study.

PubMed

Mathews, Maria; Kandar, Rima; Slade, Steve; Yi, Yanqing; Beardall, Sue; Bourgeault, Ivy

2017-06-19

International medical graduates must realize a series of milestones to obtain full licensure. We examined the realization of milestones by Canadian and non-Canadian graduates of Western or Caribbean medical schools, and Canadian and non-Canadian graduates from other medical schools. Using the National IMG Database (data available for 2005-2011), we created 2 cohorts: 1) international medical graduates who had passed the Medical Council of Canada Qualifying Examination Part I between 2005 and 2010 and 2) those who had first entered a family medicine postgraduate program between 2005 and 2009, or had first entered a specialty postgraduate program in 2005 or 2006. We examined 3 entry-to-practice milestones; obtaining a postgraduate position, passing the Medical Council of Canada Qualifying Examination Part II and obtaining a specialty designation. Of the 6925 eligible graduates in cohort 1, 2144 (31.0%) had obtained a postgraduate position. Of the 1214 eligible graduates in cohort 2, 1126 (92.8%) had passed the Qualifying Examination Part II, and 889 (73.2%) had obtained a specialty designation. In multivariate analyses, Canadian graduates of Western or Caribbean medical schools (odds ratio [OR] 4.69, 95% confidence interval [CI] 3.82-5.71) and Canadian graduates of other medical schools (OR 1.49, 95% CI 1.31-1.70) were more likely to obtain a postgraduate position than non-Canadian graduates of other (not Western or Caribbean) medical schools. There was no difference among the groups in passing the Qualifying Examination Part II or obtaining a specialty designation. Canadians who studied abroad were more likely than other international medical graduates to obtain a postgraduate position; there were no differences among the groups in realizing milestones once in a postgraduate program. These findings support policies that do not distinguish postgraduate applicants by citizenship or permanent residency status before medical school. Copyright 2017, Joule Inc. or its licensors.

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.

Active-comparator design and new-user design in observational studies

PubMed Central

Yoshida, Kazuki; Solomon, Daniel H.; Kim, Seoyoung C.

2015-01-01

SUMMARY Over the past decade, an increasing number of observational studies have examined the effectiveness or safety of rheumatoid arthritis treatments. However, unlike randomized controlled trials (RCTs), observational studies of drug effects face methodological challenges including confounding by indication. Two design principles - active comparator design and new user design can help mitigate such challenges in observational studies. To improve validity of study findings, observational studies should be designed in such a way that makes them more closely approximate RCTs. The active comparator design compares the drug of interest to another commonly used agent for the same indication, rather than a ‘non-user’ group. This principle helps select treatment groups similar in treatment indications (both measured and unmeasured characteristics). The new user design includes a cohort of patients from the time of treatment initiation, so that it can assess patients’ pretreatment characteristics and capture all events occurring anytime during follow-up. PMID:25800216

Lack of Association Between Maternal or Neonatal Vitamin D Status and Risk of Childhood Type 1 Diabetes: A Scandinavian Case-Cohort Study.

PubMed

Thorsen, Steffen U; Mårild, Karl; Olsen, Sjurdur F; Holst, Klaus K; Tapia, German; Granström, Charlotta; Halldorsson, Thorhallur I; Cohen, Arieh S; Haugen, Margaretha; Lundqvist, Marika; Skrivarhaug, Torild; Njølstad, Pål R; Joner, Geir; Magnus, Per; Størdal, Ketil; Svensson, Jannet; Stene, Lars C

2018-06-01

Studies on vitamin D status during pregnancy and risk of type 1 diabetes mellitus (T1D) lack consistency and are limited by small sample sizes or single measures of 25-hydroxyvitamin D (25(OH)D). We investigated whether average maternal 25(OH)D plasma concentrations during pregnancy are associated with risk of childhood T1D. In a case-cohort design, we identified 459 children with T1D and a random sample (n = 1,561) from the Danish National Birth Cohort (n = 97,127) and Norwegian Mother and Child Cohort Study (n = 113,053). Participants were born between 1996 and 2009. The primary exposure was the estimated average 25(OH)D concentration, based on serial samples from the first trimester until delivery and on umbilical cord plasma. We estimated hazard ratios using weighted Cox regression adjusting for multiple confounders. The adjusted hazard ratio for T1D per 10-nmol/L increase in the estimated average 25(OH)D concentration was 1.00 (95% confidence interval: 0.90, 1.10). Results were consistent in both cohorts, in multiple sensitivity analyses, and when we analyzed mid-pregnancy or cord blood separately. In conclusion, our large study demonstrated that normal variation in maternal or neonatal 25(OH)D is unlikely to have a clinically important effect on risk of childhood T1D.

Does Educational Status Impact Adult Mortality in Denmark? A Twin Approach

PubMed Central

Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

2010-01-01

To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921–1950 and followed during 1980–2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921–1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men. PMID:20530466

Antipsychotic Use and Risk of Hospitalization or Death Due to Pneumonia in Persons With and Those Without Alzheimer Disease.

PubMed

Tolppanen, Anna-Maija; Koponen, Marjaana; Tanskanen, Antti; Lavikainen, Piia; Sund, Reijo; Tiihonen, Jari; Hartikainen, Sirpa; Taipale, Heidi

2016-12-01

The use of antipsychotic agents has been associated with increased pneumonia risk, but although people with dementia are particularly susceptible to pneumonia, only one small study has assessed the risk of pneumonia in relation to the use of antipsychotic agents among people with Alzheimer disease (AD). We investigated whether the incident use of antipsychotic agents, or specific antipsychotic agents, are related to a higher risk of hospitalization or death due to pneumonia in the Medication and Alzheimer Disease (MEDALZ) cohort. The cohort includes all individuals with AD who received a clinically verified AD diagnosis in Finland in 2005 to 2011 (N = 60,584; incident pneumonia, n = 12,225). A matched comparison cohort without AD (N = 60,584; incident pneumonia, n = 6,195) was used to compare the magnitude of risk. Results were adjusted for a propensity score derived from comorbidities, concomitant medications, and sociodemographic characteristics. Sensitivity analyses with case-crossover design were conducted. The use of antipsychotic agents was associated with a higher risk of pneumonia (adjusted hazard ratio [HR], 2.01; 95% CI, 1.90-2.13) in the AD cohort and a somewhat higher risk in the non-AD cohort (adjusted HR, 3.43; 95% CI, 2.99-3.93). Similar results were observed with case-crossover analyses (OR, 2.02; 95% CI, 1.75-2.34 in the AD cohort and OR, 2.59; 95% CI, 1.77-3.79 in the non-AD cohort). The three most commonly used antipsychotic agents (quetiapine, risperidone, haloperidol) had similar associations with pneumonia risk. Regardless of applied study design, treatment duration, or the choice of drug, the use of antipsychotic agents was associated with a higher risk of pneumonia. With observational data, we cannot fully rule out a shared causality between pneumonia and the use of antipsychotic agents, but the risk to benefit balance should be considered when antipsychotic agents are prescribed. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

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.

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

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

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…

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.

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.

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

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.

Early effects of resident work-hour restrictions on patient safety: a systematic review and plea for improved studies.

PubMed

Baldwin, Keith; Namdari, Surena; Donegan, Derek; Kamath, Atul F; Mehta, Samir

2011-01-19

since the inception of the eighty-hour work week, work hour restrictions have incited considerable debate. Work hour policies were designed to prevent medical errors and to reduce patient morbidity and mortality. It is unclear whether work hour restrictions have been helpful in medicine in general and in orthopaedic surgery specifically. This systematic review of the literature was designed to determine the success of these restrictions in terms of patient mortality, medical errors, and complications. a systematic review of the literature was performed to determine if work hour rules have improved patient and systems-based outcomes and reduced physician errors as measured by mortality, medical errors, and complications. A random effects model was utilized to determine whether patient mortality rates were improved under the new rules. the odds of patient death before implementation of the work hour rules were 1.12 (95% confidence interval, 1.07 to 1.17) times those after implementation. These differences were consistent across disciplines. The data concerning medical or surgical complications before and after the institution of the work hour rules were mixed. There was little information in these studies concerning direct medical errors. The odds of death in nonteaching cohorts were not significantly different from that in teaching cohorts. there appears to be a decrease in mortality following the institution of work hour rules. The difference seen in teaching cohorts is not significantly different from that in nonteaching cohorts. It is unclear whether this difference would have been observed even without work hour restrictions. No study has shown a reduction in mortality for orthopaedic patients in teaching cohorts that was greater than that observed in nonteaching cohorts. Because of methodological concerns and the lack of current literature linking physician fatigue and physician underperformance with patient mortality, it is unclear whether the goals of the work hour reductions have been achieved. Furthermore, because of a lack of a so-called dose-response relationship between work hour reduction and patient mortality, it is uncertain whether further reductions would be beneficial. therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

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.

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

Subgroup identification of early preterm birth (ePTB): informing a future prospective enrichment clinical trial design.

PubMed

Zhang, Chuanwu; Garrard, Lili; Keighley, John; Carlson, Susan; Gajewski, Byron

2017-01-10

Despite the widely recognized association between the severity of early preterm birth (ePTB) and its related severe diseases, little is known about the potential risk factors of ePTB and the sub-population with high risk of ePTB. Moreover, motivated by a future confirmatory clinical trial to identify whether supplementing pregnant women with docosahexaenoic acid (DHA) has a different effect on the risk subgroup population or not in terms of ePTB prevalence, this study aims to identify potential risk subgroups and risk factors for ePTB, defined as babies born less than 34 weeks of gestation. The analysis data (N = 3,994,872) were obtained from CDC and NCHS' 2014 Natality public data file. The sample was split into independent training and validation cohorts for model generation and model assessment, respectively. Logistic regression and CART models were used to examine potential ePTB risk predictors and their interactions, including mothers' age, nativity, race, Hispanic origin, marital status, education, pre-pregnancy smoking status, pre-pregnancy BMI, pre-pregnancy diabetes status, pre-pregnancy hypertension status, previous preterm birth status, infertility treatment usage status, fertility enhancing drug usage status, and delivery payment source. Both logistic regression models with either 14 or 10 ePTB risk factors produced the same C-index (0.646) based on the training cohort. The C-index of the logistic regression model based on 10 predictors was 0.645 for the validation cohort. Both C-indexes indicated a good discrimination and acceptable model fit. The CART model identified preterm birth history and race as the most important risk factors, and revealed that the subgroup with a preterm birth history and a race designation as Black had the highest risk for ePTB. The c-index and misclassification rate were 0.579 and 0.034 for the training cohort, and 0.578 and 0.034 for the validation cohort, respectively. This study revealed 14 maternal characteristic variables that reliably identified risk for ePTB through either logistic regression model and/or a CART model. Moreover, both models efficiently identify risk subgroups for further enrichment clinical trial design.

Carpal tunnel syndrome and computer exposure at work in two large complementary cohorts.

PubMed

Mediouni, Z; Bodin, J; Dale, A M; Herquelot, E; Carton, M; Leclerc, A; Fouquet, N; Dumontier, C; Roquelaure, Y; Evanoff, B A; Descatha, A

2015-09-09

The boom in computer use and concurrent high rates in musculoskeletal complaints and carpal tunnel syndrome (CTS) among users have led to a controversy about a possible link. Most studies have used cross-sectional designs and shown no association. The present study used longitudinal data from two large complementary cohorts to evaluate a possible relationship between CTS and the performance of computer work. The Cosali cohort is a representative sample of a French working population that evaluated CTS using standardised clinical examinations and assessed self-reported computer use. The PrediCTS cohort study enrolled newly hired clerical, service and construction workers in several industries in the USA, evaluated CTS using symptoms and nerve conduction studies (NCS), and estimated exposures to computer work using a job exposure matrix. During a follow-up of 3-5 years, the association between new cases of CTS and computer work was calculated using logistic regression models adjusting for sex, age, obesity and relevant associated disorders. In the Cosali study, 1551 workers (41.8%) completed follow-up physical examinations; 36 (2.3%) participants were diagnosed with CTS. In the PrediCTS study, 711 workers (64.2%) completed follow-up evaluations, whereas 31 (4.3%) had new cases of CTS. The adjusted OR for the group with the highest exposure to computer use was 0.39 (0.17; 0.89) in the Cosali cohort and 0.16 (0.05; 0.59) in the PrediCTS cohort. Data from two large cohorts in two different countries showed no association between computer work and new cases of CTS among workers in diverse jobs with varying job exposures. CTS is far more common among workers in non-computer related jobs; prevention efforts and work-related compensation programmes should focus on workers performing forceful hand exertion. 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.

Carpal tunnel syndrome and computer exposure at work in two large complementary cohorts

PubMed Central

Mediouni, Z; Bodin, J; Dale, A M; Herquelot, E; Carton, M; Leclerc, A; Fouquet, N; Dumontier, C; Roquelaure, Y; Evanoff, B A; Descatha, A

2015-01-01

Objectives The boom in computer use and concurrent high rates in musculoskeletal complaints and carpal tunnel syndrome (CTS) among users have led to a controversy about a possible link. Most studies have used cross-sectional designs and shown no association. The present study used longitudinal data from two large complementary cohorts to evaluate a possible relationship between CTS and the performance of computer work. Settings and participants The Cosali cohort is a representative sample of a French working population that evaluated CTS using standardised clinical examinations and assessed self-reported computer use. The PrediCTS cohort study enrolled newly hired clerical, service and construction workers in several industries in the USA, evaluated CTS using symptoms and nerve conduction studies (NCS), and estimated exposures to computer work using a job exposure matrix. Primary and secondary outcome measures During a follow-up of 3–5 years, the association between new cases of CTS and computer work was calculated using logistic regression models adjusting for sex, age, obesity and relevant associated disorders. Results In the Cosali study, 1551 workers (41.8%) completed follow-up physical examinations; 36 (2.3%) participants were diagnosed with CTS. In the PrediCTS study, 711 workers (64.2%) completed follow-up evaluations, whereas 31 (4.3%) had new cases of CTS. The adjusted OR for the group with the highest exposure to computer use was 0.39 (0.17; 0.89) in the Cosali cohort and 0.16 (0.05; 0.59) in the PrediCTS cohort. Conclusions Data from two large cohorts in two different countries showed no association between computer work and new cases of CTS among workers in diverse jobs with varying job exposures. CTS is far more common among workers in non-computer related jobs; prevention efforts and work-related compensation programmes should focus on workers performing forceful hand exertion. PMID:26353869

Study designs for determining and comparing sensitivities of disease screening tests.

PubMed

Prorok, Philip C; Kramer, Barnett S; Miller, Anthony B

2015-12-01

To investigate the capability of various study designs to determine the sensitivity of a disease screening test. Quantities that can be calculated from these designs were derived and examined for their relationship to true sensitivity (the ability to detect unrecognized disease that would surface clinically in the absence of screening) and overdiagnosis. To examine the sensitivity of one test, the single cohort design, in which all participants receive the test, is particularly weak, providing only an upper bound on the true sensitivity, and yields no information about overdiagnosis. A randomized design, with one control arm and participants tested in the other, that includes sufficient post-screening follow-up, allows calculation of bounds on, and an approximation to, true sensitivity and also determination of overdiagnosis. Without follow-up, bounds on the true sensitivity can be calculated. To compare two tests, the single cohort paired design in which all participants receive both tests is precarious. The three arm randomized design with post screening follow-up is preferred, yielding an approximation to the true sensitivity, bounds on the true sensitivity, and the extent of overdiagnosis of each test. Without post screening follow-up, bounds on the true sensitivities can be calculated. When an unscreened control arm is not possible, the two-arm randomized design is recommended. Individual test sensitivities cannot be determined, but with sufficient post-screening follow-up, an order relationship can be established, as can the difference in overdiagnosis between the two tests. © The Author(s) 2015.

Embedding clinical interventions into observational studies.

PubMed

Newman, Anne B; Avilés-Santa, M Larissa; Anderson, Garnet; Heiss, Gerardo; Howard, Wm James; Krucoff, Mitchell; Kuller, Lewis H; Lewis, Cora E; Robinson, Jennifer G; Taylor, Herman; Treviño, Roberto P; Weintraub, William

2016-01-01

Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed. Copyright © 2015. Published by Elsevier Inc.

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

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.

LOW COST, LOW BURDEN, EXPOSURE MONITORING STRATEGIES

EPA Science Inventory

A birth cohort study designed to evaluate the association between exposures to environmental agents and health outcomes presents many challenges for exposure monitoring. Exposure of the child must be measured for multiple chemicals through multiply pathways over an extended peri...

Association between circulating vitamin K1 and coronary calcium progression in community-dwelling adults: the Multi-Ethnic Study of Atherosclerosis

USDA-ARS?s Scientific Manuscript database

While animal studies found vitamin K treatment reduced vascular calcification, human data are limited. Using a case-cohort design, we determined the association between vitamin K status and coronary artery calcium (CAC) progression in the Multi-ethnic Study of Atherosclerosis. Serum phylloquinone (v...

A Phenomenological Study to Discover Low-Income Adults' Perceptions and Expectations Regarding Financial Literacy

ERIC Educational Resources Information Center

Schaffer, Brigid Ann

2013-01-01

This phenomenological study explored the perceptions and expectations of low income adults regarding financial literacy to discover ways to increase attendance in financial literacy programs designs for this cohort. The study utilized interviews with closed-ended questions to establish the participants' backgrounds, then opened-ended questions to…

Serotonin reuptake inhibitors in pregnancy and the risk of major malformations: a systematic review.

PubMed

Bellantuono, Cesario; Migliarese, Giovanni; Gentile, Salvatore

2007-04-01

To review studies conducted to establish the risk of major congenital malformations in women exposed to serotonin reuptake inhibitors (SRIs) during the first trimester of pregnancy. A literature search [corrected] was conducted within PsycINFO [corrected] EMBASE, MEDLINE and Cochrane databases from 1966 to October 2006, to identify studies assessing the risk of major malformations in infants whose mother was taking SRIs (SSRIs and SNRIs) during the first trimester of pregnancy. Fifteen studies were selected for the analysis: seven adopted a prospective cohort design and seven a retrospective design, of these one was a case-control study. The reviewed studies suggest that exposure to fluoxetine, sertraline, citalopram and venlafaxine in early pregnancy is not associated with an increased risk of major congenital malformations. For paroxetine, recent data call for caution in prescribing such a drug in early pregnancy. For the other SRIs, the risk remains substantially undetermined, as data are so far scanty. Given this background, large prospective cohort studies are urgently needed to better assess the risk/benefit ratio of SRIs-treatment during pregnancy. Copyright 2007 John Wiley & Sons, Ltd.

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

PubMed

Rosell-Murphy, Magdalena-Isabel; Abós-Herràndiz, Rafael; Olivella, Josep Tarrés; Alberti-Casas, Constança; Allas, Isabel García; Artés, Xavier Martinez; Günther, Ilona Krier; Malet, Isidre Grimau; Martínez, Ramon Orriols; Canela-Soler, Jaume

2013-08-06

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. 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. 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.

Chinese college freshmen’s mental health problems and their subsequent help-seeking behaviors: A cohort design (2005-2011)

PubMed Central

Liu, Fenge; Cao, Hongjian; Fang, Xiaoyi; Deng, Linyuan; Chen, Wenrui; Lin, Xiuyun; Liu, Lu; Zhao, Huichun

2017-01-01

Based on cohort data obtained from 13,085 college freshmen’s (2005 to 2011) SCL-90 (the Symptom Check-List-90) reports and their subsequent 4-year psychological counseling help-seeking records, this study examined the association between college students’ mental health problems and help-seeking behaviors across four college years. Female students’ mental health problems and help-seeking behaviors increased from the 2005 to the 2011 cohorts and no changes emerged for male students across cohorts. Overall, male students reported higher levels of mental health problems than did female students in the first college year, whereas female students reported more help-seeking behaviors than did male students in the following four college years. College students’ mental health problems was associated positively with help-seeking behaviors. College students were more likely to seek help from the college psychological counselling center when they experienced relatively few or quite a lot of mental health issues (i.e., an inversed U shape). Implications for future studies and practices are discussed. PMID:29040266

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

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…

Infant siblings and the investigation of autism risk factors

PubMed Central

2012-01-01

Infant sibling studies have been at the vanguard of autism spectrum disorders (ASD) research over the past decade, providing important new knowledge about the earliest emerging signs of ASD and expanding our understanding of the developmental course of this complex disorder. Studies focused on siblings of children with ASD also have unrealized potential for contributing to ASD etiologic research. Moving targeted time of enrollment back from infancy toward conception creates tremendous opportunities for optimally studying risk factors and risk biomarkers during the pre-, peri- and neonatal periods. By doing so, a traditional sibling study, which already incorporates close developmental follow-up of at-risk infants through the third year of life, is essentially reconfigured as an enriched-risk pregnancy cohort study. This review considers the enriched-risk pregnancy cohort approach of studying infant siblings in the context of current thinking on ASD etiologic mechanisms. It then discusses the key features of this approach and provides a description of the design and implementation strategy of one major ASD enriched-risk pregnancy cohort study: the Early Autism Risk Longitudinal Investigation (EARLI). PMID:22958474

ExplorinG frailty and mild cognitive impairmEnt in kidney tRansplantation to predict biomedicAl, psychosocial and health cost outcomeS (GERAS): protocol of a nationwide prospective cohort study.

PubMed

Mauthner, Oliver; Claes, Veerle; Walston, Jeremy; Engberg, Sandra; Binet, Isabelle; Dickenmann, Michael; Golshayan, Déla; Hadaya, Karine; Huynh-Do, Uyen; Calciolari, Stefano; De Geest, Sabina

2017-03-01

To present the rationale, design and methodology of the GERAS project, which examines whether assessment of frailty and mild cognitive impairment could enhance risk prediction for biomedical, psychosocial outcomes and foster efficient resource allocation in kidney transplantation. For the burgeoning cohort of older patients considered for kidney transplantation, evidence gaps regarding frailty and mild cognitive impairment limit clinical decision-making and medical management. As known risk factors for 'hard' clinical outcomes in chronic illness, both require further study in transplantation. Integrating these and other bio-psychosocial factors into a comprehensive pre-transplant patient assessment will provide insights regarding economic implications and may improve risk prediction. A nation-wide multi-centre prospective cohort study nested in the Swiss Transplant Cohort Study. Our nationally representative convenience sample includes 250 adult kidney transplant recipients. Data sources include the Swiss Transplant Cohort Study and primary data collected at time of transplantation, 6 months, 1 and 2 years post-transplant via established measures (the Montreal Cognitive Assessment, Psychosocial Questionnaire, Fried Frailty Instrument and a blood analysis), investigator-developed instruments and datasets compiled by hospitals' management control units, sickness funds, the Swiss Federal Statistical Office and the European Renal Association. Descriptive, competing risk survival and mixed effects analyses will be performed. Research Ethics Committee approval was obtained in January 2016. This pioneering project jointly examines frailty and mild cognitive impairment from bio-psychosocial and health economic perspectives. Results may significantly inform risk prediction, care tailoring and resource optimization to improve health outcomes in the ageing kidney transplant cohort. © 2016 John Wiley & Sons Ltd.

Exposing college students to exercise: the training interventions and genetics of exercise response (TIGER) study

USDA-ARS?s Scientific Manuscript database

The Training Interventions and Genetics of Exercise Response (TIGER) study is an exercise program designed to introduce sedentary college students to regular physical activity and to identify genetic factors that influence response to exercise. A multiracial/ethnic cohort (N = 1,567; 39% male), age ...

Developmental Changes in Executive Functioning

ERIC Educational Resources Information Center

Lee, Kerry; Bull, Rebecca; Ho, Ringo M. H.

2013-01-01

Although early studies of executive functioning in children supported Miyake et al.'s (2000) three-factor model, more recent findings supported a variety of undifferentiated or two-factor structures. Using a cohort-sequential design, this study examined whether there were age-related differences in the structure of executive functioning among…

Developing Online Communities for Librarian Researchers: A Case Study

ERIC Educational Resources Information Center

Luo, Lili; Kennedy, Marie; Brancolini, Kristine; Stephens, Michael

2017-01-01

This study examines the role of online communities in connecting and supporting librarian researchers, through the analysis of member activities in the online community for academic librarians that attended the 2014 Institute for Research Design in Librarianship (IRDL). The 2014 IRDL cohort members participated in the online community via Twitter…

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

A Trigger-based Design for Evaluating the Safety of In Utero Antiretroviral Exposure in Uninfected Children of Human Immunodeficiency Virus-Infected Mothers

PubMed Central

Williams, Paige L.; Seage, George R.; Van Dyke, Russell B.; Siberry, George K.; Griner, Raymond; Tassiopoulos, Katherine; Yildirim, Cenk; Read, Jennifer S.; Huo, Yanling; Hazra, Rohan; Jacobson, Denise L.; Mofenson, Lynne M.; Rich, Kenneth

2012-01-01

The Pediatric HIV/AIDS Cohort Study’s Surveillance Monitoring of ART Toxicities Study is a prospective cohort study conducted at 22 US sites between 2007 and 2011 that was designed to evaluate the safety of in utero antiretroviral drug exposure in children not infected with human immunodeficiency virus who were born to mothers who were infected. This ongoing study uses a “trigger-based” design; that is, initial assessments are conducted on all children, and only those meeting certain thresholds or “triggers” undergo more intensive evaluations to determine whether they have had an adverse event (AE). The authors present the estimated rates of AEs for each domain of interest in the Surveillance Monitoring of ART Toxicities Study. They also evaluated the efficiency of this trigger-based design for estimating AE rates and for testing associations between in utero exposures to antiretroviral drugs and AEs. The authors demonstrate that estimated AE rates from the trigger-based design are unbiased after correction for the sensitivity of the trigger for identifying AEs. Even without correcting for bias based on trigger sensitivity, the trigger approach is generally more efficient for estimating AE rates than is evaluating a random sample of the same size. Minor losses in efficiency when comparing AE rates between persons exposed and unexposed in utero to particular antiretroviral drugs or drug classes were observed under most scenarios. PMID:22491086

Population pharmacokinetics of conventional and intermittent dosing of liposomal amphotericin B in adults: a first critical step for rational design of innovative regimens.

PubMed

Hope, William W; Goodwin, Joanne; Felton, Timothy W; Ellis, Michael; Stevens, David A

2012-10-01

There is increased interest in intermittent regimen of liposomal amphotericin B, which may facilitate use in ambulatory settings. Little is known, however, about the most appropriate dosage and schedule of administration. Plasma pharmacokinetic data were acquired from 30 patients receiving liposomal amphotericin B for empirical treatment of suspected invasive fungal infection. Two cohorts were studied. The first cohort received 3 mg of liposomal amphotericin B/kg of body weight/day; the second cohort received 10 mg of liposomal amphotericin B/kg at time zero, followed by 5 mg/kg at 48 and 120 h. The levels of liposomal amphotericin B were measured by high-pressure liquid chromatography (HPLC). The pharmacokinetics were estimated by using a population methodology. Monte Carlo simulations were performed. D-optimal design was used to identify maximally informative sampling times for both conventional and intermittent regimens for future studies. A three-compartment pharmacokinetic model best described the data. The pharmacokinetics for both conventional and intermittent dosing were linear. The estimates for the mean (standard deviation) for clearance and the volume of the central compartment were 1.60 (0.85) liter/h and 20.61 (15.27) liters, respectively. Monte Carlo simulations demonstrated considerable variability in drug exposure. Bayesian estimates for clearance and volume increased in a linear manner with weight, but only the former was statistically significant (P = 0.039). D-optimal design provided maximally informative sampling times for future pharmacokinetic studies. The pharmacokinetics of a conventional and an intermittently administered high-dose regimen liposomal amphotericin B are linear. Further pharmacokinetic-pharmacodynamic preclinical and clinical studies are required to identify safe and effective intermittent regimens.

Population Pharmacokinetics of Conventional and Intermittent Dosing of Liposomal Amphotericin B in Adults: a First Critical Step for Rational Design of Innovative Regimens

PubMed Central

Goodwin, Joanne; Felton, Timothy W.; Ellis, Michael; Stevens, David A.

2012-01-01

There is increased interest in intermittent regimen of liposomal amphotericin B, which may facilitate use in ambulatory settings. Little is known, however, about the most appropriate dosage and schedule of administration. Plasma pharmacokinetic data were acquired from 30 patients receiving liposomal amphotericin B for empirical treatment of suspected invasive fungal infection. Two cohorts were studied. The first cohort received 3 mg of liposomal amphotericin B/kg of body weight/day; the second cohort received 10 mg of liposomal amphotericin B/kg at time zero, followed by 5 mg/kg at 48 and 120 h. The levels of liposomal amphotericin B were measured by high-pressure liquid chromatography (HPLC). The pharmacokinetics were estimated by using a population methodology. Monte Carlo simulations were performed. D-optimal design was used to identify maximally informative sampling times for both conventional and intermittent regimens for future studies. A three-compartment pharmacokinetic model best described the data. The pharmacokinetics for both conventional and intermittent dosing were linear. The estimates for the mean (standard deviation) for clearance and the volume of the central compartment were 1.60 (0.85) liter/h and 20.61 (15.27) liters, respectively. Monte Carlo simulations demonstrated considerable variability in drug exposure. Bayesian estimates for clearance and volume increased in a linear manner with weight, but only the former was statistically significant (P = 0.039). D-optimal design provided maximally informative sampling times for future pharmacokinetic studies. The pharmacokinetics of a conventional and an intermittently administered high-dose regimen liposomal amphotericin B are linear. Further pharmacokinetic-pharmacodynamic preclinical and clinical studies are required to identify safe and effective intermittent regimens. PMID:22869566

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.

Risk of lymphoma and leukaemia after bacille Calmette-Guérin and smallpox vaccination: a Danish case-cohort study.

PubMed

Villumsen, Marie; Sørup, Signe; Jess, Tine; Ravn, Henrik; Relander, Thomas; Baker, Jennifer L; Benn, Christine Stabell; Sørensen, Thorkild I A; Aaby, Peter; Roth, Adam

2009-11-16

Vaccines may have non-specific effects as suggested mainly in mortality studies from low-income countries. The objective was to examine the effects of BCG and smallpox vaccinations on subsequent risk of lymphoma and leukaemia in a Danish population experiencing rapid out-phasing of these vaccines. In a background cohort (N=47,622) from the Copenhagen School Health Records Register, cases of leukaemia (N=20) and lymphoma (N=51) were identified through the Danish Cancer Registry. The vaccination status of the cases was compared with the vaccination status of a 5% random sample (N=2073) of the background cohort and analysed in a case-cohort design. BCG vaccination reduced the risk of lymphomas (HR=0.49 (95% CI: 0.26-0.93)), whereas smallpox vaccination did not (HR=1.32 (0.56-3.08)). With the small number of leukaemia cases, the analysis of leukaemia had limited power (BCG vaccination HR=0.81 (0.31-2.16); smallpox vaccination HR=1.32 (0.49-3.53)). The present study with very reliable vaccine history information indicates a beneficial effect of BCG vaccination on the risk of lymphomas.

Natural Language Processing for Asthma Ascertainment in Different Practice Settings.

PubMed

Wi, Chung-Il; Sohn, Sunghwan; Ali, Mir; Krusemark, Elizabeth; Ryu, Euijung; Liu, Hongfang; Juhn, Young J

We developed and validated NLP-PAC, a natural language processing (NLP) algorithm based on predetermined asthma criteria (PAC) for asthma ascertainment using electronic health records at Mayo Clinic. To adapt NLP-PAC in a different health care setting, Sanford Children Hospital, by assessing its external validity. The study was designed as a retrospective cohort study that used a random sample of 2011-2012 Sanford Birth cohort (n = 595). Manual chart review was performed on the cohort for asthma ascertainment on the basis of the PAC. We then used half of the cohort as a training cohort (n = 298) and the other half as a blind test cohort to evaluate the adapted NLP-PAC algorithm. Association of known asthma-related risk factors with the Sanford-NLP algorithm-driven asthma ascertainment was tested. Among the eligible test cohort (n = 297), 160 (53%) were males, 268 (90%) white, and the median age was 2.3 years (range, 1.5-3.1 years). NLP-PAC, after adaptation, and the human abstractor identified 74 (25%) and 72 (24%) subjects, respectively, with 66 subjects identified by both approaches. Sensitivity, specificity, positive predictive value, and negative predictive value for the NLP algorithm in predicting asthma status were 92%, 96%, 89%, and 97%, respectively. The known risk factors for asthma identified by NLP (eg, smoking history) were similar to the ones identified by manual chart review. Successful implementation of NLP-PAC for asthma ascertainment in 2 different practice settings demonstrates the feasibility of automated asthma ascertainment leveraging electronic health record data with a potential to enable large-scale, multisite asthma studies to improve asthma care and research. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

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 Bayesian multi-stage cost-effectiveness design for animal studies in stroke research

PubMed Central

Cai, Chunyan; Ning, Jing; Huang, Xuelin

2017-01-01

Much progress has been made in the area of adaptive designs for clinical trials. However, little has been done regarding adaptive designs to identify optimal treatment strategies in animal studies. Motivated by an animal study of a novel strategy for treating strokes, we propose a Bayesian multi-stage cost-effectiveness design to simultaneously identify the optimal dose and determine the therapeutic treatment window for administrating the experimental agent. We consider a non-monotonic pattern for the dose-schedule-efficacy relationship and develop an adaptive shrinkage algorithm to assign more cohorts to admissible strategies. We conduct simulation studies to evaluate the performance of the proposed design by comparing it with two standard designs. These simulation studies show that the proposed design yields a significantly higher probability of selecting the optimal strategy, while it is generally more efficient and practical in terms of resource usage. PMID:27405325

A Longitudinal Assessment of Sleep Timing, Circadian Phase, and Phase Angle of Entrainment across Human Adolescence

PubMed Central

Crowley, Stephanie J.; Van Reen, Eliza; LeBourgeois, Monique K.; Acebo, Christine; Tarokh, Leila; Seifer, Ronald; Barker, David H.; Carskadon, Mary A.

2014-01-01

The aim of this descriptive analysis was to examine sleep timing, circadian phase, and phase angle of entrainment across adolescence in a longitudinal study design. Ninety-four adolescents participated; 38 (21 boys) were 9–10 years (“younger cohort”) and 56 (30 boys) were 15–16 years (“older cohort”) at the baseline assessment. Participants completed a baseline and then follow-up assessments approximately every six months for 2.5 years. At each assessment, participants wore a wrist actigraph for at least one week at home to measure self-selected sleep timing before salivary dim light melatonin onset (DLMO) phase – a marker of the circadian timing system – was measured in the laboratory. Weekday and weekend sleep onset and offset and weekend-weekday differences were derived from actigraphy. Phase angles were the time durations from DLMO to weekday sleep onset and offset times. Each cohort showed later sleep onset (weekend and weekday), later weekend sleep offset, and later DLMO with age. Weekday sleep offset shifted earlier with age in the younger cohort and later in the older cohort after age 17. Weekend-weekday sleep offset differences increased with age in the younger cohort and decreased in the older cohort after age 17. DLMO to sleep offset phase angle narrowed with age in the younger cohort and became broader in the older cohort. The older cohort had a wider sleep onset phase angle compared to the younger cohort; however, an age-related phase angle increase was seen in the younger cohort only. Individual differences were seen in these developmental trajectories. This descriptive study indicated that circadian phase and self-selected sleep delayed across adolescence, though school-day sleep offset advanced until no longer in high school, whereupon offset was later. Phase angle changes are described as an interaction of developmental changes in sleep regulation interacting with psychosocial factors (e.g., bedtime autonomy). PMID:25380248

Breast feeding and intergenerational social mobility: what are the mechanisms?

PubMed Central

Sacker, A; Kelly, Y; Iacovou, M; Cable, N; Bartley, M

2013-01-01

Objective To investigate the association between breast feeding and intergenerational social mobility and the possible mediating role of neurological and stress mechanisms. Design Secondary analysis of data from the 1958 and the 1970 British Cohort Studies. Setting Longitudinal study of individuals born in Britain during 1 week in 1958 and 1970. Participants 17 419 individuals participated in the 1958 cohort and 16 771 in the 1970 cohort. The effect of breast feeding on intergenerational social mobility from age 10/11 to age 33/34 was analysed after multiple imputations to fill in missing data and propensity score matching on a wide range of confounders measured in childhood (1958 cohort N=16 039–16 154; 1970 cohort N=16 255–16 361). Main outcome measures Own Registrar General's Social Class (RGSC) at 33/34 years adjusted for father's RGSC at 10/11 years, gender and their interaction. Results Breastfed individuals were more likely to be upwardly mobile (1958 cohort: OR 1.24 95% CI 1.12 to 1.38; 1970 cohort: OR 1.24 95% CI 1.12 to 1.37) and less likely to be downwardly mobile (1958 cohort: OR 0.81 95% CI 0.73 to 0.90; 1970 cohort: OR 0.79 95% CI 0.71 to 0.88). In an ordinal regression model, markers of neurological development (cognitive test scores) and stress (emotional stress scores) accounted for approximately 36% of the relationship between breast feeding and social mobility. Conclusions Breast feeding increased the odds of upward social mobility and decreased the odds of downward mobility. Consistent with a causal explanation, the findings were robust to matching on a large number of observable variables and effect sizes were alike for two cohorts with different social distributions of breast feeding. The effect was mediated in part through neurological and stress mechanisms. PMID:23798701

Tribocorrosion: Ceramic and Oxidized Zirconium vs Cobalt-Chromium Heads in Total Hip Arthroplasty.

PubMed

Tan, Sok Chuen; Lau, Adrian C K; Del Balso, Christopher; Howard, James L; Lanting, Brent A; Teeter, Matthew G

2016-09-01

This matched-cohort study aims to compare tribocorrosion between matched ceramic and cobalt-chromium femoral head trunnions and between matched Oxinium and cobalt-chromium femoral head trunnions. Secondary objectives were to investigate whether taper design, depth of trunnion, implantation time, age, body mass index, and gender have an effect on fretting and corrosion. All hip prostheses retrieved between 1999 and 2015 at one center were reviewed, giving a total of 52 ceramic heads. These were matched to a cobalt-chromium cohort according to taper design, head size, neck length, and implantation time. The trunnions were examined by 2 observers using a 4-point scoring technique and scored in 3 zones: apex, middle, and base. The observers were blinded to clinical and manufacturing data where possible. A separate matched-cohort analysis was performed between 8 Oxinium heads and 8 cobalt-chromium heads, which were similarly scored. Ceramic head trunnions demonstrated a lower median fretting and corrosion score at the base zone (P < .001), middle zone (P < .001), and in the combined score (P < .001). Taper design had a significant effect on fretting and corrosion in the apex zone (P = .04) of the ceramic group, as well as the cobalt-chromium group (P = .03). Between Oxinium heads and cobalt-chromium heads, there was no significant difference in the fretting and corrosion score across all 3 zones (base: P = .22; middle: P = .92; and apex: P = .71) and for the combined score (P = .67). This study shows that ceramic head confers an advantage in trunnion fretting and corrosion. Taper design and implantation time were also significant factors for fretting and corrosion. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

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

Association Between Whole-Body Vibration and Low-Back Disorders in Farmers: A Scoping Review.

PubMed

Kwaku Essien, Samuel; Trask, Catherine; Khan, Muhammad; Boden, Catherine; Bath, Brenna

2018-01-01

Low-back disorders (LBDs) are the most common musculoskeletal problem among farmers, with higher prevalence rates than in other occupations. Farmers who operate tractors and other types of machinery can have substantial exposure to whole-body vibration (WBV). Although there appears to be an association between LBDs and WBV, the causal relationship is not clear. This scoping review investigates the association between WBV and LBDs specifically among farmers. Nine databases were searched using groups of terms for two concepts: 'farming' and 'low back disorder'. Screening, data extraction, and quality assessment were performed by two reviewers independently. Included studies met the following criteria: focused on adult farmers/agricultural workers; assessed exposure to operating farm machinery such tractor, combine, or all-terrain vehicle; assessed LBDs as an outcome; and reported an inferential test to assess the relationship between WBV and LBD. After 276 full texts screened, 11 articles were found to analyze WBV as a risk factor for LBDs. Three were case-control, five cross-sectional, and three retrospective cohorts. Four studies showed no association between WBV and LBDs, four a positive association, and three results were mixed depending on the exposure/outcome measure. A firm conclusion is difficult due to heterogeneity in, LBDs definition, type of farm commodity, study design, and statistical strategy. Direct comparisons and synthesis were not possible. Although retrospective cohort studies tended to show a relationship, future studies with a prospective cohort design could help clarify this association further.

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.

Gout Can Increase the Risk of Receiving Rotator Cuff Tear Repair Surgery.

PubMed

Huang, Shih-Wei; Wu, Chin-Wen; Lin, Li-Fong; Liou, Tsan-Hon; Lin, Hui-Wen

2017-08-01

Gout commonly involves joint inflammation, and clinical epidemiological studies on involved tendons are scant. Rotator cuff tears are the most common cause of shoulder disability, and surgery is one of the choices often adopted to regain previous function. To investigate the risk of receiving rotator cuff repair surgery among patients with gout and to analyze possible risk factors to design an effective prevention strategy. Cohort study; Level of evidence, 3. The authors studied a 7-year longitudinal follow-up of patients from the Taiwan Longitudinal Health Insurance Database 2005 (LHID2005). This included a cohort of patients who received a diagnosis of gout during 2004-2008 (gout cohort) and a cohort matched by propensity scores (control cohort). A 2-stage approach that used the National Health Interview Survey 2005 was used to obtain missing confounding variables from the LHID2005. The crude hazard ratio (HR) and adjusted HR were estimated between the gout and control cohorts. The gout and control cohorts comprised 32,723 patients with gout and 65,446 people matched at a ratio of 1:2. The incidence of rotator cuff repair was 31 and 18 per 100,000 person-years in the gout and control cohorts, respectively. The crude HR for rotator cuff repair in the gout cohort was 1.73 (95% confidence interval [CI], 1.23-2.44; P < .01) during the 7-year follow-up period. After adjustment for covariates by use of the 2-stage approach, the propensity score calibration-adjusted HR was 1.60 (95% CI, 1.12-2.29; P < .01) in the gout cohort. Further analysis revealed that the adjusted HR was 1.73 (95% CI, 1.20-2.50; P < .001) among patients with gout who did not take hypouricemic medication and 2.70 (95% CI, 1.31-5.59; P < .01) for patients with gout aged 50 years or younger. Patients with gout, particularly those aged 50 years or younger and without hypouricemic medication control, are at a relatively higher risk of receiving rotator cuff repair surgery. Strict control of uric acid levels with hypouricemic medication may effectively reduce the risk of rotator cuff repair.

A pilot study to understand feasibility and acceptability of stool and cord blood sample collection for a large-scale longitudinal birth cohort.

PubMed

Bailey, S R; Townsend, C L; Dent, H; Mallet, C; Tsaliki, E; Riley, E M; Noursadeghi, M; Lawley, T D; Rodger, A J; Brocklehurst, P; Field, N

2017-12-28

Few data are available to guide biological sample collection around the time of birth for large-scale birth cohorts. We are designing a large UK birth cohort to investigate the role of infection and the developing immune system in determining future health and disease. We undertook a pilot to develop methodology for the main study, gain practical experience of collecting samples, and understand the acceptability of sample collection to women in late pregnancy. Between February-July 2014, we piloted the feasibility and acceptability of collecting maternal stool, baby stool and cord blood samples from participants recruited at prolonged pregnancy and planned pre-labour caesarean section clinics at University College London Hospital. Participating women were asked to complete acceptability questionnaires. Overall, 265 women were approached and 171 (65%) participated, with ≥1 sample collected from 113 women or their baby (66%). Women had a mean age of 34 years, were primarily of white ethnicity (130/166, 78%), and half were nulliparous (86/169, 51%). Women undergoing planned pre-labour caesarean section were more likely than those who delivered vaginally to provide ≥1 sample (98% vs 54%), but less likely to provide maternal stool (10% vs 43%). Pre-sample questionnaires were completed by 110/171 women (64%). Most women reported feeling comfortable with samples being collected from their baby (<10% uncomfortable), but were less comfortable about their own stool (19% uncomfortable) or a vaginal swab (24% uncomfortable). It is possible to collect a range of biological samples from women around the time of delivery, and this was acceptable for most women. These data inform study design and protocol development for large-scale birth cohorts.

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.

Overweight in adult cats: a cross-sectional study.

PubMed

Öhlund, Malin; Palmgren, Malin; Holst, Bodil Ström

2018-01-19

Overweight in cats is a major risk factor for diabetes mellitus and has also been associated with other disorders. Overweight and obesity are believed to be increasing problems in cats, as is currently seen in people, with important health consequences. The objectives of the present study were to determine the prevalence of overweight in cats from two different cohorts in a cross-sectional study design and to assess associations between overweight and diagnoses, and between overweight and demographic and environmental factors. Data were obtained from medical records for cats (n = 1072) visiting an academic medical center during 2013-2015, and from a questionnaire on insured cats (n = 1665). From the medical records, information on body condition score, breed, age, sex, neutering status, and diagnosis was obtained. The questionnaire included questions relating to the cat's body condition, breed, age, sex, neutering status, outdoor access, activity level, and diet. Data were analyzed by multivariable logistic regression. The prevalence of overweight was 45% in the medical records cohort and 22% in the questionnaire cohort, where owners judged their pet's body condition. Overweight cats in the medical records cohort were more likely to be diagnosed with lower urinary tract disease, diabetes mellitus, respiratory disease, skin disorders, locomotor disease, and trauma. Eating predominantly dry food, being a greedy eater, and inactivity were factors associated with an increased risk of overweight in the final model in the questionnaire cohort. In both cohorts, the Birman and Persian breeds, and geriatric cats, were less likely to be overweight, and male cats were more likely to be overweight. The prevalence of overweight cats (45%) as assessed by trained personnel was high and in the same range as previously reported. Birman and Persian cats had a lower risk of overweight. The association with dry food found in adult, neutered cats is potentially important because this type of food is commonly fed to cats worldwide, and warrants further attention. Drawbacks related to the study design need to be acknowledged when interpreting the results, such as a potential for selection bias for cats visiting an animal hospital, and an information bias for questionnaire data. The high occurrence of overweight in cats needs to be addressed because it negatively affects their health.

Substituting dietary monounsaturated fat for saturated fat is associated with increased daily physical activity and resting energy expenditure and with changes in mood123

PubMed Central

Bunn, Janice Y; Tompkins, Connie L; Dumas, Julie A; Crain, Karen I; Ebenstein, David B; Koves, Timothy R; Muoio, Deborah M

2013-01-01

Background: The Western diet increases risk of metabolic disease. Objective: We determined whether lowering the ratio of saturated fatty acids to monounsaturated fatty acids in the Western diet would affect physical activity and energy expenditure. Design: With the use of a balanced design, 2 cohorts of 18 and 14 young adults were enrolled in separate randomized, double-masked, crossover trials that compared a 3-wk high–palmitic acid diet (HPA; similar to the Western diet fat composition) to a low–palmitic acid and high–oleic acid diet (HOA; similar to the Mediterranean diet fat composition). All foods were provided by the investigators, and the palmitic acid (PA):oleic acid (OA) ratio was manipulated by adding different oil blends to the same foods. In both cohorts, we assessed physical activity (monitored continuously by using accelerometry) and resting energy expenditure (REE). To gain insight into a possible mood disturbance that might explain changes in physical activity, the Profile of Mood States (POMS) was administered in cohort 2. Results: Physical activity was higher during the HOA than during the HPA in 15 of 17 subjects in cohort 1 (P = 0.008) (mean: 12% higher; P = 0.003) and in 12 of 12 subjects in the second, confirmatory cohort (P = 0.005) (mean: 15% higher; P = 0.003). When the HOA was compared with the HPA, REE measured during the fed state was 3% higher for cohort 1 (P < 0.01), and REE was 4.5% higher in the fasted state for cohort 2 (P = 0.04). POMS testing showed that the anger-hostility score was significantly higher during the HPA (P = 0.007). Conclusions: The replacement of dietary PA with OA was associated with increased physical activity and REE and less anger. Besides presumed effects on mitochondrial function (increased REE), the dietary PA:OA ratio appears to affect behavior. The second cohort was derived from a study that was registered at clinicaltrials.gov as R01DK082803. PMID:23446891

Is there a causal link between knee loading and knee osteoarthritis progression? A systematic review and meta-analysis of cohort studies and randomised trials

PubMed Central

Henriksen, Marius; Creaby, Mark W; Lund, Hans; Juhl, Carsten; Christensen, Robin

2014-01-01

Objective We performed a systematic review, meta-analysis and assessed the evidence supporting a causal link between knee joint loading during walking and structural knee osteoarthritis (OA) progression. Design Systematic review, meta-analysis and application of Bradford Hill's considerations on causation. Data sources We searched MEDLINE, Scopus, AMED, CINAHL and SportsDiscus for prospective cohort studies and randomised controlled trials (RCTs) from 1950 through October 2013. Study eligibility criteria We selected cohort studies and RCTs in which estimates of knee joint loading during walking were used to predict structural knee OA progression assessed by X-ray or MRI. Data analyses Meta-analysis was performed to estimate the combined OR for structural disease progression with higher baseline loading. The likelihood of a causal link between knee joint loading and OA progression was assessed from cohort studies using the Bradford Hill guidelines to derive a 0–4 causation score based on four criteria and examined for confirmation in RCTs. Results Of the 1078 potentially eligible articles, 5 prospective cohort studies were included. The studies included a total of 452 patients relating joint loading to disease progression over 12–72 months. There were very serious limitations associated with the methodological quality of the included studies. The combined OR for disease progression was 1.90 (95% CI 0.85 to 4.25; I2=77%) for each one-unit increment in baseline knee loading. The combined causation score was 0, indicating no causal association between knee loading and knee OA progression. No RCTs were found to confirm or refute the findings from the cohort studies. Conclusions There is very limited and low-quality evidence to support for a causal link between knee joint loading during walking and structural progression of knee OA. Trial registration number CRD42012003253 PMID:25031196

[Design and implementation of the ELSA-Brasil biobank: a prospective study in a Brazilian population].

PubMed

Pereira, Alexandre C; Bensenor, Isabela M; Fedeli, Ligia M; Castilhos, Cristina; Vidigal, Pedro G; Maniero, Viviane; Leite, Claudia M; Pimentel, Robercia A; Duncan, Bruce B; Mill, Jose Geraldo; Lotufo, Paulo A

2013-06-01

The Brazilian Longitudinal Study for Adult Health (ELSA-Brasil) is a multicenter prospective cohort of civil servants designed to assess the determinants of chronic diseases, especially cardiovascular diseases and type 2 diabetes. The present article describes the main design and implementation points of the ELSA-Brasil biobank project. Economic, political, logistical and technological aspects of this study are characterized. Additionally, it discusses the final biorepository protocol and the facilities implemented to achieve this objective. The design and implementation process of the ELSA-Brasil biobank took three years to be performed. Both the central and local biobanks were built according to the best biorepository techniques, using different technological solutions for the distinct needs expected in this study.

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.

Basic principles of test-negative design in evaluating influenza vaccine effectiveness.

PubMed

Fukushima, Wakaba; Hirota, Yoshio

2017-08-24

Based on the unique characteristics of influenza, the concept of "monitoring" influenza vaccine effectiveness (VE) across the seasons using the same observational study design has been developed. In recent years, there has been a growing number of influenza VE reports using the test-negative design, which can minimize both misclassification of diseases and confounding by health care-seeking behavior. Although the test-negative designs offer considerable advantages, there are some concerns that widespread use of the test-negative design without knowledge of the basic principles of epidemiology could produce invalid findings. In this article, we briefly review the basic concepts of the test-negative design with respect to classic study design such as cohort studies or case-control studies. We also mention selection bias, which may be of concern in some countries where rapid diagnostic testing is frequently used in routine clinical practices, as in Japan. Copyright © 2017. Published by Elsevier Ltd.

Screening for carcinoma in situ in the contralateral testicle in patients with testicular cancer: a population-based study.

PubMed

Kier, M G G; Lauritsen, J; Almstrup, K; Mortensen, M S; Toft, B G; Rajpert-De Meyts, E; Skakkebaek, N E; Rørth, M; von der Maase, H; Agerbaek, M; Holm, N V; Andersen, K K; Dalton, S O; Johansen, C; Daugaard, G

2015-04-01

Screening programmes for contralateral carcinoma in situ (CIS) testis in patients with unilateral germ-cell cancer (GCC) have never been evaluated. We investigated the effect of screening for contralateral CIS in a large nation-wide, population-based study. A contralateral single-site biopsy was offered to 4130 patients in whom GCC had been diagnosed in 1984-2007 (screened cohort); 462 patients in whom GCC was diagnosed in 1984-1988 comprised the unscreened cohort. Cases with CIS were offered radiotherapy. Initially CIS-negative biopsies in patients with metachronous GCC were revised according to today's standards. Risk for metachronous GCC was estimated using cumulative incidence and the Cox proportional hazards model. In the screened cohort, contralateral CIS was found in 181 (4.4%) patients. The cumulative incidence of metachronous GCC after 20 years was 1.9% in the screened cohort and 3.1% in the unscreened cohort (P = 0.097), hazard ratio (HR) for the unscreened cohort: 1.59 (P = 0.144). Expert revision with contemporary methodology of CIS-negative biopsy samples from patients with metachronous cancer revealed CIS in 17 out of 45 (38%) cases. Decreased risks for metachronous GCC were related to older age at diagnosis (HR 0.52 per 10 years, P < 0.001) and chemotherapy (HR 0.35, P = 0.002). Limitations include the small number of patients in the unscreened cohort and the retrospective study design. Our evaluation of a national population-based screening programme for contralateral CIS in patients with testicular cancer showed no significant difference in the risk for metachronous GCC between a screened and an unscreened cohort. Single-site biopsy including modern immunohistochemistry does not identify all cases of CIS. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

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.

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 Shozu Herpes Zoster (SHEZ) study: rationale, design, and description of a prospective cohort study.

PubMed

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

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. 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. 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. 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.

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

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

A nationwide population-based cohort study to identify the correlation between heart failure and the subsequent risk of herpes zoster.

PubMed

Wu, Ping-Hsun; Lin, Yi-Ting; Lin, Chun-Yi; Huang, Ming-Yii; Chang, Wei-Chiao; Chang, Wei-Pin

2015-01-16

The association between heart failure (HF) and herpes zoster has rarely been studied. We investigated the hypothesis that HF may increase the risk of herpes zoster in Taiwan using a nationwide Taiwanese population-based claims database. Our study cohort consisted of patients who received a diagnosis of HF in 2001 ~ 2009 (N = 4785). For a comparison cohort, three age- and gender-matched control patients for every patient in the study cohort were selected using random sampling (N = 14,355). All subjects were tracked for 1 year from the date of cohort entry to identify whether or not they had developed herpes zoster. Cox proportional-hazard regressions were performed to evaluate 1-year herpes zoster-free survival rates. The main finding of this study was that patients with HF seemed to be at an increased risk of developing herpes zoster. Of the total patients, 211 patients developed herpes zoster during the 1-year follow-up period, among whom 83 were HF patients and 128 were in the comparison cohort. The adjusted hazard ratio (AHR) of herpes zoster in patients with HF was higher (AHR: 2.07; 95% confidence interval (CI): 1.54 ~ 2.78; p < 0.001) than that of the controls during the 1-year follow-up. Our study also investigated whether HF is a gender-dependent risk factor for herpes zoster. We found that male patients with HF had an increased risk of developing herpes zoster (AHR: 2.30 95% CI: 1.51 ~ 3.50; p < 0.001). The findings of our population-based study suggest that patients with HF may have an increased risk of herpes zoster. These health associations should be taken into consideration, and further studies should focused on the cost-effectiveness of the herpes zoster vaccine should be designed for HF patients.

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

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.

Moving from Theory to Practice: Implementing the Kin Keeper[superscript SM] Cancer Prevention Model

ERIC Educational Resources Information Center

Williams, K. P.; Mullan, P. B.; Todem, D.

2009-01-01

This paper presents the rationale and findings of a feasibility and process study of the Kin Keeper[superscript SM] Cancer Prevention Intervention. An observational cohort study design was implemented with African-American women in synergistic female family relationships. Community health workers (CHWs) from two Michigan public health programs…

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:…

Supplemental Reading Strategy Instruction for Adolescents: A Randomized Trial and Follow-up Study

ERIC Educational Resources Information Center

Cantrell, Susan Chambers; Almasi, Janice F.; Rintamaa, Margaret; Carter, Janis C.

2016-01-01

In this study, the authors examine the impact of a yearlong supplemental reading course involving daily instruction in the learning strategies curriculum on lower achieving adolescent students' reading achievement and motivation. Using a multiple-cohort randomized treatment-control group design over 4 years, they compared achievement and…

The Role of Advanced High School Coursework in Increasing STEM Career Interest

ERIC Educational Resources Information Center

Sadler, Philip M.; Sonnert, Gerhard; Hazari, Zahra; Tai, Robert

2014-01-01

Several avenues are open to students who wish to study advanced science or mathematics in high school, which include Advanced Placement courses and teacher-designed courses unaffiliated with organized programs. We employ a retrospective cohort study of 4,691 nationally representative college students at 34 randomly selected, colleges and…

77 FR 26773 - Agency Information Collection Activities: Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-07

... enhanced and standard data collection and a longitudinal cohort design, and will include a comparative study to assess the effectiveness of HTI relative to a similar sample of young persons who did not... total hourly cost of the study. Summary Burden Table Average annual Average 3-year Number of number...

Effects of fat mass on motor development during the first two years of life

USDA-ARS?s Scientific Manuscript database

Objective: This study characterized total body fat mass and motor development during the first two years of life in healthy infants. Design: Participants (N=469) from the Beginnings’ cohort, a prospective, longitudinal study of early infant feeding, were assessed at 3, 6, 9, 12 and 24 months of age...

A Bridge Program's Effect on Non-College Ready Student Veterans

ERIC Educational Resources Information Center

Morris, Brett Eugene

2013-01-01

This study examined whether a bridge program designed to remediate academic deficiencies for a cohort of student veterans has any bearing on their post-secondary success and persistence. Specifically, this study examined the Veterans Bridge to College Success (VBCS) pilot program at Eastern Kentucky University, which provides an admission pathway…

The Optimal Screening for Prediction of Referral and Outcome (OSPRO) in patients with musculoskeletal pain conditions: a longitudinal validation cohort from the USA

PubMed Central

George, Steven Z; Beneciuk, Jason M; Lentz, Trevor A; Wu, Samuel S

2017-01-01

Purpose There is an increased need for determining which patients with musculoskeletal pain benefit from additional diagnostic testing or psychologically informed intervention. The Optimal Screening for Prediction of Referral and Outcome (OSPRO) cohort studies were designed to develop and validate standard assessment tools for review of systems and yellow flags. This cohort profile paper provides a description of and future plans for the validation cohort. Participants Patients (n=440) with primary complaint of spine, shoulder or knee pain were recruited into the OSPRO validation cohort via a national Orthopaedic Physical Therapy-Investigative Network. Patients were followed up at 4 weeks, 6 months and 12 months for pain, functional status and quality of life outcomes. Healthcare utilisation outcomes were also collected at 6 and 12 months. Findings to date There are no longitudinal findings reported to date from the ongoing OSPRO validation cohort. The previously completed cross-sectional OSPRO development cohort yielded two assessment tools that were investigated in the validation cohort. Future plans Follow-up data collection was completed in January 2017. Primary analyses will investigate how accurately the OSPRO review of systems and yellow flag tools predict 12-month pain, functional status, quality of life and healthcare utilisation outcomes. Planned secondary analyses include prediction of pain interference and/or development of chronic pain, investigation of treatment expectation on patient outcomes and analysis of patient satisfaction following an episode of physical therapy. Trial registration number The OSPRO validation cohort was not registered. PMID:28600371

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

Polish mother and child cohort study--defining the problem, the aim of the study and methodological assumption.

PubMed

Polańska, Kinga; Hanke, Wojciech; Gromadzińska, Jolanta; Ligocka, Danuta; Gulczyńska, Ewa; Sobala, Wojciech; Wásowicz, Wojciech

2009-01-01

Exposures during prenatal period have implications for pregnancy outcome as well as for children's health, morbidity and mortality. Prospective cohort study design allows for the identification of exposures that may influence pregnancy outcome and children's health, verification of such exposures by biomarker measurements and notification of any changes in exposure level. Polish Mother and Child Cohort Study (REPRO_PL) is multicenter prospective cohort study conducted in 8 different regions of Poland. The final cohort is intended to comprise 1300 mother-child pairs to be recruited within 4-year period (2007-2011). The recruitment and all scheduled visits are conducted in maternity units or clinics in the districts included in the study. The women are followed-up 3 times in pregnancy (once in each trimester) and after delivery for the notification of pregnancy outcome. During each visit, detailed questionnaire and biological samples are collected including saliva, urine, hair, maternal blood and cord blood. About 6 weeks postpartum, breast milk from part of the women is collected. The study concentrates on the identification and evaluation of the effects of prenatal environmental exposure on pregnancy outcome and children's health. Specific research hypotheses refer to the role of heavy metals, exposure to polycyclic aromatic hydrocarbons (PAHs) and environmental tobacco smoke (ETS) in the aetiology of small-for-gestational-age (SGA) and preterm delivery (PD). The role of oxidative stress putative mechanism and pregnant women nutritional status will be investigated. Based on questionnaire data, the impact of occupational exposures and stressful situations will be evaluated. The results of the study will become available within the next few years and will help to determine levels of child prenatal exposure in several areas of Poland and its impact on course and outcome of pregnancy.

Decline of kidney function during the pre-dialysis period in chronic kidney disease patients: a systematic review and meta-analysis.

PubMed

Janmaat, Cynthia J; van Diepen, Merel; van Hagen, Cheyenne Ce; Rotmans, Joris I; Dekker, Friedo W; Dekkers, Olaf M

2018-01-01

Substantial heterogeneity exists in reported kidney function decline in pre-dialysis chronic kidney disease (CKD). By design, kidney function decline can be studied in CKD 3-5 cohorts or dialysis-based studies. In the latter, patients are selected based on the fact that they initiated dialysis, possibly leading to an overestimation of the true underlying kidney function decline in the pre-dialysis period. We performed a systematic review and meta-analysis to compare the kidney function decline during pre-dialysis in CKD stage 3-5 patients, in these two different study types. We searched PubMed, EMBASE, Web of Science and Cochrane to identify eligible studies reporting an estimated glomerular filtration rate (eGFR) decline (mL/min/1.73 m 2 ) in adult pre-dialysis CKD patients. Random-effects meta-analysis was performed to obtain weighted mean annual eGFR decline. We included 60 studies (43 CKD 3-5 cohorts and 17 dialysis-based studies). The meta-analysis yielded a weighted annual mean (95% CI) eGFR decline during pre-dialysis of 2.4 (95% CI: 2.2, 2.6) mL/min/1.73 m 2 in CKD 3-5 cohorts compared to 8.5 (95% CI: 6.8, 10.1) in dialysis-based studies (difference 6.0 [95% CI: 4.8, 7.2]). To conclude, dialysis-based studies report faster mean annual eGFR decline during pre-dialysis than CKD 3-5 cohorts. Thus, eGFR decline data from CKD 3-5 cohorts should be used to guide clinical decision making in CKD patients and for power calculations in randomized controlled trials with CKD progression during pre-dialysis as the outcome.

PRImary care Streptococcal Management (PRISM) study: identifying clinical variables associated with Lancefield group A β-haemolytic streptococci and Lancefield non-Group A streptococcal throat infections from two cohorts of patients presenting with an acute sore throat

PubMed Central

Little, Paul; Moore, Michael; Hobbs, F D R; Mant, David; McNulty, Cliodna; Williamson, Ian; Cheng, Edith; Stuart, Beth; Kelly, Joanne; Barnett, Jane; Mullee, Mark

2013-01-01

Objective To assess the association between features of acute sore throat and the growth of streptococci from culturing a throat swab. Design Diagnostic cohort. Setting UK general practices. Participants Patients aged 5 or over presenting with an acute sore throat. Patients were recruited for a second cohort (cohort 2, n=517) consecutively after the first (cohort 1, n=606) from similar practices. Main outcome Predictors of the presence of Lancefield A/C/G streptococci. Results The clinical score developed from cohort 1 had poor discrimination in cohort 2 (bootstrapped estimate of area under the receiver operator characteristic (ROC) curve (0.65), due to the poor validity of the individual items in the second data set. Variables significant in multivariate analysis in both cohorts were rapid attendance (prior duration 3 days or less; multivariate adjusted OR 1.92 cohort, 1.67 cohort 2); fever in the last 24 h (1.69, 2.40); and doctor assessment of severity (severely inflamed pharynx/tonsils (2.28, 2.29)). The absence of coryza or cough and purulent tonsils were significant in univariate analysis in both cohorts and in multivariate analysis in one cohort. A five-item score based on Fever, Purulence, Attend rapidly (3 days or less), severely Inflamed tonsils and No cough or coryza (FeverPAIN) had moderate predictive value (bootstrapped area under the ROC curve 0.73 cohort 1, 0.71 cohort 2) and identified a substantial number of participants at low risk of streptococcal infection (38% in cohort 1, 36% in cohort 2 scored ≤1, associated with a streptococcal percentage of 13% and 18%, respectively). A Centor score of ≤1 identified 23% and 26% of participants with streptococcal percentages of 10% and 28%, respectively. Conclusions Items widely used to help identify streptococcal sore throat may not be the most consistent. A modified clinical scoring system (FeverPAIN) which requires further validation may be clinically helpful in identifying individuals who are unlikely to have major pathogenic streptococci. PMID:24163209

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

ERIC Educational Resources Information Center

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…

Member Perceptions of Informal Science Institution Graduate Certificate Program: Case Study of a Community of Practice

NASA Astrophysics Data System (ADS)

Ball, Lois A.

This research attempted to understand the experiences of a cohort of informal and formal science educators and informal science institution (ISI) community representatives during and after completion of a pilot graduate certificate program. Informal science educators (ISEs) find limited opportunities for professional development and support which influence their contributions to America's science literacy and school science education. This emergent design nested case study described how an innovative program provided professional development and enabled growth in participants' abilities to contribute to science literacy. Data were collected through interviews, participant observations, and class artifacts. The program by design and constituency was the overarching entity that accounted for members' experiences. Three principal aspects of the ISI certificate program and cohort which influenced perceptions and reported positive outcomes were (1) the cohort's composition and their collaborative activities which established a vigorous community of practice and fostered community building, mentoring, and networking, (2) long term program design and implementation which promoted experiential learning in a generative classroom, and (3) ability of some members who were able to be independent or autonomous learners to embrace science education reform strategies for greater self-efficacy and career advancement. This research extends the limited literature base for professional development of informal science educators and may benefit informal science institutions, informal and formal science educators, science education reform efforts, and public education and science-technology-society understanding. The study may raise awareness of the need to establish more professional development opportunities for ISEs and to fund professional development. Further, recognizing and appreciating informal science educators as a diverse committed community of professionals who positively influence science education for everyone is essential.

Study protocol: the JEU cohort study--transversal multiaxial evaluation and 5-year follow-up of a cohort of French gamblers.

PubMed

Challet-Bouju, Gaëlle; Hardouin, Jean-Benoit; Vénisse, Jean-Luc; Romo, Lucia; Valleur, Marc; Magalon, David; Fatséas, Mélina; Chéreau-Boudet, Isabelle; Gorsane, Mohamed-Ali; Grall-Bronnec, Marie

2014-08-20

There is abundant literature on how to distinguish problem gambling (PG) from social gambling, but there are very few studies of the long-term evolution of gambling practice. As a consequence, the correlates of key state changes in the gambling trajectory are still unknown. The objective of the JEU cohort study is to identify the determinants of key state changes in the gambling practice, such as the emergence of a gambling problem, natural recovery from a gambling problem, resolution of a gambling problem with intermediate care intervention, relapses or care recourse. The present study was designed to overcome the limitations of previous cohort study on PG. Indeed, this longitudinal case-control cohort is the first which plans to recruit enough participants from different initial gambling severity levels to observe these rare changes. In particular, we plan to recruit three groups of gamblers: non-problem gamblers, problem gamblers without treatment and problem gamblers seeking treatment.Recruitment takes place in various gambling places, through the press and in care centers. Cohort participants are gamblers of both sexes who reported gambling on at least one occasion in the previous year and who were aged between 18 and 65. They were assessed through a structured clinical interview and self-assessment questionnaires at baseline and then once a year for five years. Data collection comprises sociodemographic characteristics, gambling habits (including gambling trajectory), the PG section of the DSM-IV, the South Oaks Gambling Screen, the Gambling Attitudes and Beliefs Survey - 23, the Mini International Neuropsychiatric Interview, the Wender-Utah Rating Scale-Child, the Adult ADHD Self-report Scale, somatic comorbidities (especially current treatment and Parkinson disease) and the Temperament and Character Inventory - 125. The JEU cohort study is the first study which proposes to identify the predictive factors of key state changes in gambling practice. This is the first case-control cohort on gambling which mixes non-problem gamblers, problem gamblers without treatment and problem gamblers seeking treatment in almost equal proportions. This work may help providing a fresh perspective on the etiology of pathological gambling, which may provide support for future research, care and preventive actions. (ClinicalTrials.gov): NCT01207674.

A Severe Sepsis Mortality Prediction Model and Score for Use with Administrative Data

PubMed Central

Ford, Dee W.; Goodwin, Andrew J.; Simpson, Annie N.; Johnson, Emily; Nadig, Nandita; Simpson, Kit N.

2016-01-01

Objective Administrative data is used for research, quality improvement, and health policy in severe sepsis. However, there is not a sepsis-specific tool applicable to administrative data with which to adjust for illness severity. Our objective was to develop, internally validate, and externally validate a severe sepsis mortality prediction model and associated mortality prediction score. Design Retrospective cohort study using 2012 administrative data from five US states. Three cohorts of patients with severe sepsis were created: 1) ICD-9-CM codes for severe sepsis/septic shock, 2) ‘Martin’ approach, and 3) ‘Angus’ approach. The model was developed and internally validated in ICD-9-CM cohort and externally validated in other cohorts. Integer point values for each predictor variable were generated to create a sepsis severity score. Setting Acute care, non-federal hospitals in NY, MD, FL, MI, and WA Subjects Patients in one of three severe sepsis cohorts: 1) explicitly coded (n=108,448), 2) Martin cohort (n=139,094), and 3) Angus cohort (n=523,637) Interventions None Measurements and Main Results Maximum likelihood estimation logistic regression to develop a predictive model for in-hospital mortality. Model calibration and discrimination assessed via Hosmer-Lemeshow goodness-of-fit (GOF) and C-statistics respectively. Primary cohort subset into risk deciles and observed versus predicted mortality plotted. GOF demonstrated p>0.05 for each cohort demonstrating sound calibration. C-statistic ranged from low of 0.709 (sepsis severity score) to high of 0.838 (Angus cohort) suggesting good to excellent model discrimination. Comparison of observed versus expected mortality was robust although accuracy decreased in highest risk decile. Conclusions Our sepsis severity model and score is a tool that provides reliable risk adjustment for administrative data. PMID:26496452

Quality Assessment of Studies Published in Open Access and Subscription Journals: Results of a Systematic Evaluation.

PubMed

Pastorino, Roberta; Milovanovic, Sonja; Stojanovic, Jovana; Efremov, Ljupcho; Amore, Rosarita; Boccia, Stefania

2016-01-01

Along with the proliferation of Open Access (OA) publishing, the interest for comparing the scientific quality of studies published in OA journals versus subscription journals has also increased. With our study we aimed to compare the methodological quality and the quality of reporting of primary epidemiological studies and systematic reviews and meta-analyses published in OA and non-OA journals. In order to identify the studies to appraise, we listed all OA and non-OA journals which published in 2013 at least one primary epidemiologic study (case-control or cohort study design), and at least one systematic review or meta-analysis in the field of oncology. For the appraisal, we picked up the first studies published in 2013 with case-control or cohort study design from OA journals (Group A; n = 12), and in the same time period from non-OA journals (Group B; n = 26); the first systematic reviews and meta-analyses published in 2013 from OA journals (Group C; n = 15), and in the same time period from non-OA journals (Group D; n = 32). We evaluated the methodological quality of studies by assessing the compliance of case-control and cohort studies to Newcastle and Ottawa Scale (NOS) scale, and the compliance of systematic reviews and meta-analyses to Assessment of Multiple Systematic Reviews (AMSTAR) scale. The quality of reporting was assessed considering the adherence of case-control and cohort studies to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist, and the adherence of systematic reviews and meta-analyses to Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) checklist. Among case-control and cohort studies published in OA and non-OA journals, we did not observe significant differences in the median value of NOS score (Group A: 7 (IQR 7-8) versus Group B: 8 (7-9); p = 0.5) and in the adherence to STROBE checklist (Group A, 75% versus Group B, 80%; p = 0.1). The results did not change after adjustment for impact factor. The compliance with AMSTAR and adherence to PRISMA checklist were comparable between systematic reviews and meta-analyses published in OA and non-OA journals (Group C, 46.0% versus Group D, 55.0%; p = 0.06), (Group C, 72.0% versus Group D, 76.0%; p = 0.1), respectively). The epidemiological studies published in OA journals in the field of oncology approach the same methodological quality and quality of reporting as studies published in non-OA journals.

Quality Assessment of Studies Published in Open Access and Subscription Journals: Results of a Systematic Evaluation

PubMed Central

Pastorino, Roberta; Milovanovic, Sonja; Stojanovic, Jovana; Efremov, Ljupcho; Amore, Rosarita; Boccia, Stefania

2016-01-01

Introduction Along with the proliferation of Open Access (OA) publishing, the interest for comparing the scientific quality of studies published in OA journals versus subscription journals has also increased. With our study we aimed to compare the methodological quality and the quality of reporting of primary epidemiological studies and systematic reviews and meta-analyses published in OA and non-OA journals. Methods In order to identify the studies to appraise, we listed all OA and non-OA journals which published in 2013 at least one primary epidemiologic study (case-control or cohort study design), and at least one systematic review or meta-analysis in the field of oncology. For the appraisal, we picked up the first studies published in 2013 with case-control or cohort study design from OA journals (Group A; n = 12), and in the same time period from non-OA journals (Group B; n = 26); the first systematic reviews and meta-analyses published in 2013 from OA journals (Group C; n = 15), and in the same time period from non-OA journals (Group D; n = 32). We evaluated the methodological quality of studies by assessing the compliance of case-control and cohort studies to Newcastle and Ottawa Scale (NOS) scale, and the compliance of systematic reviews and meta-analyses to Assessment of Multiple Systematic Reviews (AMSTAR) scale. The quality of reporting was assessed considering the adherence of case-control and cohort studies to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist, and the adherence of systematic reviews and meta-analyses to Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) checklist. Results Among case-control and cohort studies published in OA and non-OA journals, we did not observe significant differences in the median value of NOS score (Group A: 7 (IQR 7–8) versus Group B: 8 (7–9); p = 0.5) and in the adherence to STROBE checklist (Group A, 75% versus Group B, 80%; p = 0.1). The results did not change after adjustment for impact factor. The compliance with AMSTAR and adherence to PRISMA checklist were comparable between systematic reviews and meta-analyses published in OA and non-OA journals (Group C, 46.0% versus Group D, 55.0%; p = 0.06), (Group C, 72.0% versus Group D, 76.0%; p = 0.1), respectively). Conclusion The epidemiological studies published in OA journals in the field of oncology approach the same methodological quality and quality of reporting as studies published in non-OA journals. PMID:27167982

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

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...

Osteosarcoma inheritance in two families of Scottish deerhounds.

PubMed

Dillberger, John E; McAtee, Sara Ann

2017-01-01

Osteosarcoma is the most common neoplastic disease in Scottish Deerhounds. For Deerhounds, a 2007 population-based study concluded that a single dominant genetic factor largely governed disease risk. For Greyhounds, Rottweilers, and Irish Wolfhounds, a 2013 genome-wide association study found multiple genetic markers in each breed, with each marker only weakly associated with the disease. We obtained from two breeders the pedigrees, age (if alive) or age at death, and osteosarcoma status for two families of Scottish Deerhounds, designated Cohorts K and T. A dog was considered unaffected only if it was osteosarcoma-free and at least 8.5 years old. We analyzed the data in two ways, by assuming either a single recessive genetic factor or a single dominant genetic factor with high penetrance. Cohort K contained 54 evaluable dogs representing 12 litters. Cohort T contained 56 evaluable dogs representing eight litters. Osteosarcoma seemed clearly heritable in both cohorts; however, having a parent with osteosarcoma raised a pup's risk of developing osteosarcoma to 38% for Cohort K but 78% for Cohort T, suggesting the possibility of different genetic risk factors in each cohort. In Cohort K, osteosarcoma inheritance fit well with a single, recessive, autosomal risk factor, although we could not rule out the possibility of a single dominant risk factor with incomplete penetrance. In Cohort T, inheritance could be explained well by a single, dominant, autosomal risk factor but was inconsistent with recessive expression. Inheritance of osteosarcoma in two Scottish Deerhound families could be explained well by a single genetic risk factor residing on an autosome, consistent with a 2007 report. In one family, inheritance was consistent with dominant expression, as previously reported. In the other family, inheritance fit better with recessive expression, although the possibility of a dominant genetic factor influenced by one or more other genetic factors could not be ruled out. In either case, the results suggest that there may be at least two different genetic risk factors for osteosarcoma in Deerhounds.

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.

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

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

Sun, Si; Yu, Hui; Wang, Huijie; Zhao, Xinmin; Zhao, Xintai; Wu, Xianghua; Qiao, Jie; Chang, Jianhua; Wang, Jialei

2017-01-01

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. 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. 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. 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.

Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies.

PubMed

Atkinson, R W; Butland, B K; Dimitroulopoulou, C; Heal, M R; Stedman, J R; Carslaw, N; Jarvis, D; Heaviside, C; Vardoulakis, S; Walton, H; Anderson, H R

2016-02-23

While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted. 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/

Mammography screening trends: the perspective of African American women born pre/post World War II.

PubMed

Williams, Karen Patricia; Mabiso, Athur; Lo, Yun-Jia; Penner, Louis A

2010-06-01

Researchers have traditionally combined aging women (aged > or =50 years) when reporting their mammography use. This may inadvertently mask important cohort effects in mammography use, which are likely to result from distinct personal life experiences and generational differences. Using the Health and Retirement Study samples of 1998, 2000, and 2004, we examined cohort differences in mammography use between African American women born before 1946 (non-baby boomers) and those born in 1946 to 1953 (baby boomers). Between 1998 and 2004, screening rates for non-baby boomers declined, while those for baby boomers remained relatively steady. Hierarchical linear modeling (HLM) analyses suggest that while screening rates decreased with age (OR, 0.957; 95% CI, 0.947-0.968) cohort effects may have partially reversed the age effect, with non-baby boomers having an increased likelihood of receiving a mammogram compared to baby boomers (OR, 1.697; 95% CI, 1.278-2.254). Because African American women are diagnosed at later stages of breast cancer, documentation of cohort differences in mammography use among older African American women is important as health care professionals design intervention programs that are maximally effective for women from different cohorts. This is particularly critical as more African American women in the baby boomer cohort become part of the aging population.

Design innovations and baseline findings in a long-term Parkinson's trial: the National Institute of Neurological Disorders and Stroke Exploratory Trials in Parkinson's Disease Long-Term Study-1.

PubMed

Elm, Jordan J

2012-10-01

Based on the preclinical data and the results of a phase II 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. A randomized, multicenter, double-blind, parallel-group, placebo-controlled phase III study of creatine (10 g daily) in participants with early, treated PD, the Long-term Study-1 (LS-1), is being conducted by the National Institute of Neurological Disorders and Stroke Exploratory Trials in Parkinson's Disease network. The study utilizes a global statistical test (GST) encompassing five clinical rating scales to provide a multidimensional assessment of disease progression. A total of 1,741 PD participants from 45 sites in the United States and Canada were randomized 1:1 to either 10 g of 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. 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 (10 g/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. Copyright © 2012 Movement Disorder Society.

Rationale and design of MUSIC OS-EU: an international observational study of the treatment of postmenopausal women for osteoporosis in Europe and Canada.

PubMed

Modi, Ankita; Sen, Shuvayu; Adachi, Jonathan D; Adami, Silvano; Cortet, Bernard; Cooper, Alun L; Geusens, Piet; Mellström, Dan; Weaver, Jessica P; van den Bergh, Joop P; Nguyen, Allison M; Keown, Paul A; Leung, Albert T; Sajjan, Shiva

2015-01-01

The Medication Use Patterns, Treatment Satisfaction, and Inadequate Control of Osteoporosis Study (MUSIC OS-EU) was designed to better understand the rate and burden of gastrointestinal (GI) events on clinical and health care outcomes among postmenopausal women with osteoporosis. MUSIC OS-EU is a prospective, multinational, observational cohort study of postmenopausal women ≥50 years of age diagnosed with osteoporosis and enrolled in physician clinics in six countries: France, Italy, the Netherlands, Sweden, the United Kingdom, and Canada. The MUSIC OS-EU study has three components: (i) a physician survey to describe their management of osteoporotic patients with GI events; (ii) a retrospective chart survey to describe the receipt and type of osteoporosis medication prescribed; and (iii) a prospective cohort study including untreated and treated patients diagnosed with osteoporosis to investigate the rate of GI events and association with osteoporosis medication use patterns, health-related quality of life, treatment satisfaction and resource utilisation among postmenopausal women with osteoporosis. Physicians at 97 sites completed the physician questionnaire and data for 716 patients were abstracted for the retrospective chart review. Enrolment and the baseline data collection for the prospective cohort study were conducted between March 2012 and June 2013 for 292 untreated and 2,959 treated patients, of whom 684 were new users and 2,275 were experienced users of oral osteoporosis medications. The results of MUSIC OS-EU will illuminate the association of GI events with the management of osteoporosis and with patient-reported outcomes among postmenopausal women with osteoporosis in Europe and Canada.

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

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

Changes in Local Public Health System Performance Before and After Attainment of National Accreditation Standards.

PubMed

Ingram, Richard C; Mays, Glen P; Kussainov, Nurlan

The aim of this study is to investigate the impact of Public Health Accreditation Board (PHAB) accreditation on the delivery of public health services and on participation from other sectors in the delivery of public health services in local public health systems. This study uses a longitudinal repeated measures design to identify differences between a cohort of public health systems containing PHAB-accredited local health departments and a cohort of public health systems containing unaccredited local health departments. It uses data spanning from 2006 to 2016. This study examines a cohort of local public health systems that serves large populations and contains unaccredited and PHAB-accredited local health departments. Data in this study were collected from the directors of health departments that include local public health systems followed in the National Longitudinal Study of Public Health Systems. The intervention examined is PHAB accreditation. The study focuses on 4 areas: the delivery of core public health services, local health department contribution toward these services, participation in the delivery of these services by other members of the public health system, and public health system makeup. Prior to the advent of accreditation, public health systems containing local health departments that were later accredited by PHAB appear quite similar to their unaccredited peers. Substantial differences between the 2 cohorts appear to manifest themselves after the advent of accreditation. Specifically, the accredited cohort seems to offer a broader array of public health services, involve more partners in the delivery of those services, and enjoy a higher percentage of comprehensive public health systems. The results of this study suggest that accreditation may yield significant benefits and may help public health systems develop the public health system capital necessary to protect and promote the public's health.

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

Incidence of cancer and exposure to toluene diisocyanate and methylene diphenyldiisocyanate: a cohort based case-referent study in the polyurethane foam manufacturing industry.

PubMed Central

Hagmar, L; Strömberg, U; Welinder, H; Mikoczy, Z

1993-01-01

OBJECTIVE--To assess the association between occupational exposure to toluene diisocyanate or methylene diphenyldiisocyanate and risk of cancer. DESIGN--A cohort based case-referent study. STUDY BASE--7023 subjects employed during the period 1958 to 1987 in nine Swedish polyurethane foam manufacturing plants. MAIN OUTCOME MEASURES--Odds ratios adjusted with respect to the matching factors (age at risk, calendar year at risk, sex, and plant), calculated from the conditional logistic regression model. RESULTS--A non-significant association was found between high exposure to isocyanates and prostate cancer (OR 2.66, 90% confidence interval (90% CI) 0.39-18.1), which was not enhanced when an induction latency period of 10 years was applied. An association between isocyanate exposure and colon cancer was even weaker. No associations were seen for non-Hodgkin's lymphoma and rectal cancer. CONCLUSIONS--The tentative associations, derived from a previous cohort study, between isocyanate exposure and excess risk for non-Hodgkin's lymphoma and rectal cancer were not supported. Instead, non-significant associations with prostate cancer, and possibly colon cancer, were seen. PMID:8280625

Working Information

ERIC Educational Resources Information Center

Lloyd, Annemaree; Somerville, Margaret

2006-01-01

Purpose: The purpose of this article is to explore the contribution that an information literacy approach to the empirical study of workplace learning can make to how people understand and conceptualise workplace learning. Design/methodology/approach: Three cohorts of fire-fighters working in two regional locations in NSW, Australia were…

[Linkage of large secondary and registry data sources with data of cohort studies : usage of a dual potential].

PubMed

Jacobs, Svenja; Stallmann, Christoph; Pigeot, Iris

2015-08-01

Cohort studies provide the best evidence of all epidemiological observational studies for the identification of causal relationships between risk factors and diseases. However, this design may lead to drawbacks that may affect the validity and reliability of the results. This follows in particular from systematic errors, such as selection bias or recall bias. One possibility to avoid or counteract some of these drawbacks is to link primary data from cohort studies with secondary and register data. The linkage of these data may also be used for mutual validations. Data that were previously linked with primary data within the context of cohort studies in Germany were obtained from statutory health insurances and pensions as well as data from the Federal Employment Agency and cancer registries. All these data have two features in common: First, they all cover detailed information about a large population and over a long period of time. Second, all sources are in principle able to provide data on an individual level such that an individual data linkage, e.g. with primary data, is possible. However, use and linkage of each of these data sources are restricted by several limitations. These have to be accounted for as well as numerous legal restrictions that exist in Germany to especially prevent the misuse of social data.

A study of the birth weight-obesity relation using a longitudinal cohort and sibling and twin pairs.

PubMed

The, Natalie S; Adair, Linda S; Gordon-Larsen, Penny

2010-09-01

Sibling and twin study designs provide control for confounding factors that are typically unmeasured in traditional cohort studies. Using nationally representative data from the National Longitudinal Study of Adolescent Health collected at 3 visits during 1994-2002, the authors evaluated the longitudinal association between birth weight and later obesity in a traditional cohort study (n = 13,763; ages 11-21 years at baseline), controlling for sex, age, race/ethnicity, and parental education. Among persons with a nonobese mother, high birth weight (>4 kg) participants were more likely than normal birth weight (>/=2.5-

Selenium and Prostate Cancer Prevention: Insights from the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

PubMed Central

Nicastro, Holly L.; Dunn, Barbara K.

2013-01-01

The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was conducted to assess the efficacy of selenium and vitamin E alone, and in combination, on the incidence of prostate cancer. This randomized, double-blind, placebo-controlled, 2 × 2 factorial design clinical trial found that neither selenium nor vitamin E reduced the incidence of prostate cancer after seven years and that vitamin E was associated with a 17% increased risk of prostate cancer compared to placebo. The null result was surprising given the strong preclinical and clinical evidence suggesting chemopreventive activity of selenium. Potential explanations for the null findings include the agent formulation and dose, the characteristics of the cohort, and the study design. It is likely that only specific subpopulations may benefit from selenium supplementation; therefore, future studies should consider the baseline selenium status of the participants, age of the cohort, and genotype of specific selenoproteins, among other characteristics, in order to determine the activity of selenium in cancer prevention. PMID:23552052

Invited Commentary: Indoor Tanning-A Melanoma Accelerator?

PubMed

Berwick, Marianne; Doré, Jean-François

2017-02-01

In this issue of the Journal, Ghiasvand et al. (Am J Epidemiol. 2017;185(3):147-156) present results from a longitudinal study of the association between indoor tanning and melanoma in a large cohort of Norwegian women. These new data further support previous findings on the damaging effects of tanning bed exposure on women, particularly young women. The authors present compelling evidence that early exposure to tanning beds advances the date of diagnosis of melanoma by at least 2 years. With a strong design and a large cohort followed for a mean of 13.7 years, this study lends additional support to previous evidence of the negative effects of tanning beds and provides further justification for stronger policy initiatives designed to reduce tanning bed use among young women. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Statistical controversies in clinical research: building the bridge to phase II-efficacy estimation in dose-expansion cohorts.

PubMed

Boonstra, P S; Braun, T M; Taylor, J M G; Kidwell, K M; Bellile, E L; Daignault, S; Zhao, L; Griffith, K A; Lawrence, T S; Kalemkerian, G P; Schipper, M J

2017-07-01

Regulatory agencies and others have expressed concern about the uncritical use of dose expansion cohorts (DECs) in phase I oncology trials. Nonetheless, by several metrics-prevalence, size, and number-their popularity is increasing. Although early efficacy estimation in defined populations is a common primary endpoint of DECs, the types of designs best equipped to identify efficacy signals have not been established. We conducted a simulation study of six phase I design templates with multiple DECs: three dose-assignment/adjustment mechanisms multiplied by two analytic approaches for estimating efficacy after the trial is complete. We also investigated the effect of sample size and interim futility analysis on trial performance. Identifying populations in which the treatment is efficacious (true positives) and weeding out inefficacious treatment/populations (true negatives) are competing goals in these trials. Thus, we estimated true and false positive rates for each design. Adaptively updating the MTD during the DEC improved true positive rates by 8-43% compared with fixing the dose during the DEC phase while maintaining false positive rates. Inclusion of an interim futility analysis decreased the number of patients treated under inefficacious DECs without hurting performance. A substantial gain in efficiency is obtainable using a design template that statistically models toxicity and efficacy against dose level during expansion. Design choices for dose expansion should be motivated by and based upon expected performance. Similar to the common practice in single-arm phase II trials, cohort sample sizes should be justified with respect to their primary aim and include interim analyses to allow for early stopping. © The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

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.

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

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

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

Setting up a cohort study in speech and language therapy: lessons from The UK Cleft Collective Speech and Language (CC-SL) study.

PubMed

Wren, Yvonne; Humphries, Kerry; Stock, Nicola Marie; Rumsey, Nichola; Lewis, Sarah; Davies, Amy; Bennett, Rhiannon; Sandy, Jonathan

2018-05-01

Efforts to increase the evidence base in speech and language therapy are often limited by methodological factors that have restricted the strength of the evidence to the lower levels of the evidence hierarchy. Where higher graded studies, such as randomized controlled trials, have been carried out, it has sometimes been difficult to obtain sufficient power to detect a potential effect of intervention owing to small sample sizes or heterogeneity in the participants. With certain clinical groups such as cleft lip and palate, systematic reviews of intervention studies have shown that there is no robust evidence to support the efficacy of any one intervention protocol over another. To describe the setting up of an observational clinical cohort study and to present this as an alternative design for answering research questions relating to prevalence, risk factors and outcomes from intervention. The Cleft Collective Speech and Language (CC-SL) study is a national cohort study of children born with cleft palate. Working in partnership with regional clinical cleft centres, a sample size of over 600 children and 600 parents is being recruited and followed up from birth to age 5 years. Variables being collected include demographic, psychological, surgical, hearing, and speech and language data. The process of setting up the study has led to the creation of a unique, large-scale data set which is available for researchers to access now and in future. As well as exploring predictive factors, the data can be used to explore the impact of interventions in relation to individual differences. Findings from these investigations can be used to provide information on sample criteria and definitions of intervention and dosage which can be used in future trials. The observational cohort study is a useful alternative design to explore questions around prevalence, risk factors and intervention for clinical groups where robust research data are not yet available. Findings from such a study can be used to guide service-delivery decisions and to determine power for future clinical trials. © 2017 Royal College of Speech and Language Therapists.

Serum metabolites are associated with all-cause mortality in chronic kidney disease.

PubMed

Hu, Jiun-Ruey; Coresh, Josef; Inker, Lesley A; Levey, Andrew S; Zheng, Zihe; Rebholz, Casey M; Tin, Adrienne; Appel, Lawrence J; Chen, Jingsha; Sarnak, Mark J; Grams, Morgan E

2018-06-02

Chronic kidney disease (CKD) involves significant metabolic abnormalities and has a high mortality rate. Because the levels of serum metabolites in patients with CKD might provide insight into subclinical disease states and risk for future mortality, we determined which serum metabolites reproducibly associate with mortality in CKD using a discovery and replication design. Metabolite levels were quantified via untargeted liquid chromatography and mass spectroscopy from serum samples of 299 patients with CKD in the Modification of Diet in Renal Disease (MDRD) study as a discovery cohort. Six among 622 metabolites were significantly associated with mortality over a median follow-up of 17 years after adjustment for demographic and clinical covariates, including urine protein and measured glomerular filtration rate. We then replicated associations with mortality in 963 patients with CKD from the African American Study of Kidney Disease and Hypertension (AASK) cohort over a median follow-up of ten years. Three of the six metabolites identified in the MDRD cohort replicated in the AASK cohort: fumarate, allantoin, and ribonate, belonging to energy, nucleotide, and carbohydrate pathways, respectively. Point estimates were similar in both studies and in meta-analysis (adjusted hazard ratios 1.63, 1.59, and 1.61, respectively, per doubling of the metabolite). Thus, selected serum metabolites were reproducibly associated with long-term mortality in CKD beyond markers of kidney function in two well characterized cohorts, providing targets for investigation. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Rare copy number variants in patients with congenital conotruncal heart defects.

PubMed

Xie, Hongbo M; Werner, Petra; Stambolian, Dwight; Bailey-Wilson, Joan E; Hakonarson, Hakon; White, Peter S; Taylor, Deanne M; Goldmuntz, Elizabeth

2017-03-01

Previous studies using different cardiac phenotypes, technologies and designs suggest a burden of large, rare or de novo copy number variants (CNVs) in subjects with congenital heart defects. We sought to identify disease-related CNVs, candidate genes, and functional pathways in a large number of cases with conotruncal and related defects that carried no known genetic syndrome. Cases and control samples were divided into two cohorts and genotyped to assess each subject's CNV content. Analyses were performed to ascertain differences in overall CNV prevalence and to identify enrichment of specific genes and functional pathways in conotruncal cases relative to healthy controls. Only findings present in both cohorts are presented. From 973 total conotruncal cases, a burden of rare CNVs was detected in both cohorts. Candidate genes from rare CNVs found in both cohorts were identified based on their association with cardiac development or disease, and/or their reported disruption in published studies. Functional and pathway analyses revealed significant enrichment of terms involved in either heart or early embryonic development. Our study tested one of the largest cohorts specifically with cardiac conotruncal and related defects. These results confirm and extend previous findings that CNVs contribute to disease risk for congenital heart defects in general and conotruncal defects in particular. As disease heterogeneity renders identification of single recurrent genes or loci difficult, functional pathway and gene regulation network analyses appear to be more informative. Birth Defects Research 109:271-295, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Sexual orientation differences in teen pregnancy and hormonal contraceptive use: An examination across two generations

PubMed Central

Charlton, Brittany M.; Corliss, Heather L.; Missmer, Stacey A.; Rosario, Margaret; Spiegelman, Donna; Austin, S. Bryn

2013-01-01

Objectives To examine whether sexual orientation is associated with disparities in teen pregnancy and hormonal contraception use among adolescent females in two intergenerational cohorts. Study Design Data were collected from 91,003 women in the Nurses’ Health Study II (NHSII),born between 1947–1964, and 6,463 of their children, born between 1982–1987, enrolled in the Growing Up Today Study (GUTS). Log-binomial models were used to estimate risk ratios (RR) for teen pregnancy and hormonal contraception use in sexual minorities compared to heterosexuals and meta-analysis techniques were used to compare the two cohorts. Results Overall, teen hormonal contraception use was lower and teen pregnancy was higher in NHSII than GUTS. In both cohorts, lesbians were less likely, whereas the other sexual minorities were more likely, to use hormonal contraception as teenagers compared to their heterosexual peers. All sexual minority groups in both cohorts, except NHSII lesbians, were at significantly increased risk for teen pregnancy, with RRs ranging from 1.61 (95%CI 0.40, 6.55) to 5.82 (95%CI 2.89, 11.73). Having a NHSII mother who was pregnant as a teen was not associated with teen pregnancy in GUTS participants. Finally, significant heterogeneity was found between the two cohorts. Conclusions Adolescent sexual minorities have been, and continue to be, at increased risk for pregnancy. Public health and clinical efforts are needed to address teen pregnancy in this population. PMID:23796650

Canadian Alliance for Healthy Hearts and Minds: First Nations Cohort Study Rationale and Design.

PubMed

Anand, Sonia S; Abonyi, Sylvia; Arbour, Laura; Brook, Jeff; Bruce, Sharon; Castleden, Heather; Desai, Dipika; de Souza, Russell J; Harris, Stewart; Irvine, James; Lai, Christopher; Lewis, Diana; Oster, Richard T; Poirier, Paul; Toth, Ellen L; Bannon, Karen; Chrisjohn, Vicky; Davis, Albertha D; L'Hommecourt, Jean; Littlechild, Randy; McMullin, Kathleen; McIntosh, Sarah; Morrison, Julie; Picard, Manon; Landing First Nation, Pictou; M Thomas, Melissa; Tusevljak, Natasa; Friedrich, Matthias G; Tu, Jack V

2018-01-01

This is the first national indigenous cohort study in which a common, in-depth protocol with a common set of objectives has been adopted by several indigenous communities across Canada. The overarching objective of the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort is to investigate how the community-level environment is associated with individual health behaviors and the presence and progression of chronic disease risk factors and chronic diseases such as cardiovascular disease (CVD) and cancer. CAHHM aims to recruit approximately 2,000 First Nations indigenous individuals from up to nine communities across Canada and have participants complete questionnaires, blood collection, physical measurements, cognitive assessments, and magnetic resonance imaging (MRI). Through individual- and community-level data collection, we will develop an understanding of the specific role of the socioenvironmental, biological, and contextual factors have on the development of chronic disease risk factors and chronic diseases. Information collected in the indigenous cohort will be used to assist communities to develop local management strategies for chronic disease, and can be used collectively to understand the contextual, environmental, socioeconomic, and biological determinants of differences in health status in harmony with First Nations beliefs and reality.

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

Biologic and social determinants of sequelae and long-term survival of pediatric HIV in Romania.

PubMed

Kozinetz, Claudia A; Matusa, Rodica; Hacker, Carl S

2006-08-01

The aim of the study is to investigate the effect of social context and clinical factors on survival in a cohort of 333 children to identify issues useful in the treatment and care of human immunodeficiency virus (HIV)-infected youth in developing countries. A prospective cohort study design was used, and data were gathered at baseline and 1-year follow-up. The study cohort consisted of children given a diagnosis of HIV between 1995 and 1999 and receiving medical care in Constanta, Romania. Data were examined by means of multivariate Cox regression analysis models. The majority of the cohort were in the moderate (41%) or severe (40%) stages of HIV at baseline. Multivariate analysis indicated that social-context factors were the most significant determinants of HIV survival. The hazard for death for those with mothers or fathers with a higher level of education was approximately one quarter (relative hazard, 0.3-0.4; confidence interval, 0.1-1.0) that for a parent with a lower level of education. Subjects with employed mothers were four times more likely to survive than subjects with unemployed mothers. Results suggest that recognition of social-context risk factors for HIV disease progression and survival is important in developing countries, as it is in developed countries.

Occupational Exposure to Magnetic Fields and Breast Cancer Among Women Textile Workers in Shanghai, China

PubMed Central

Li, Wenjin; Ray, Roberta M.; Thomas, David B.; Yost, Michael; Davis, Scott; Breslow, Norman; Gao, Dao Li; Fitzgibbons, E. Dawn; Camp, Janice E.; Wong, Eva; Wernli, Karen J.; Checkoway, Harvey

2013-01-01

Exposure to magnetic fields (MFs) is hypothesized to increase the risk of breast cancer by reducing production of melatonin by the pineal gland. A nested case-cohort study was conducted to investigate the association between occupational exposure to MFs and the risk of breast cancer within a cohort of 267,400 female textile workers in Shanghai, China. The study included 1,687 incident breast cancer cases diagnosed from 1989 to 2000 and 4,702 noncases selected from the cohort. Subjects’ complete work histories were linked to a job–exposure matrix developed specifically for the present study to estimate cumulative MF exposure. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards modeling that was adapted for the case-cohort design. Hazard ratios were estimated in relation to cumulative exposure during a woman's entire working years. No association was observed between cumulative exposure to MFs and overall risk of breast cancer. The hazard ratio for the highest compared with the lowest quartile of cumulative exposure was 1.03 (95% confidence interval: 0.87, 1.21). Similar null findings were observed when exposures were lagged and stratified by age at breast cancer diagnosis. The findings do not support the hypothesis that MF exposure increases the risk of breast cancer. PMID:24043439

Is Statin Use Associated With Tendon Rupture? A Population-Based Retrospective Cohort Analysis.

PubMed

Contractor, Tahmeed; Beri, Abhimanyu; Gardiner, Joseph C; Tang, Xiaoqin; Dwamena, Francesca C

2015-01-01

Previous case reports and small studies have suggested that 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (HMG-CoA-Is) may increase the risk of tendon rupture. We conducted a population-based retrospective cohort evaluation to better assess this relationship. From approximately 800,000 enrollees of a private insurance database, those who were aged ≤64 years with at least 1 year of continuous enrollment were selected. Exposure was defined as initiation of HMG-CoA-I after the beginning of the study period. Each exposed person was matched with 2 controls of similar age and gender. Baseline characteristics, including known risk factors for tendon rupture, were compared between exposed and control cohorts with fidelity to the study's matched design. After adjusting for differences in follow-up and baseline characteristics, incidence rate ratios for tendon rupture was assessed in HMG-CoA-I users and nonusers. A total of 34,749 exposed patients were matched with 69,498 controls. There was no difference in the occurrence of tendon ruptures in HMG-CoA-I users versus nonusers. The results remained unchanged after adjustment for age and gender. In conclusion, this population-based retrospective cohort evaluation suggests that use of HMG-CoA-Is as a group are not associated with tendon rupture.

The relationship between urban environment and the inflammatory bowel diseases: a systematic review and meta-analysis.

PubMed

Soon, Ing Shian; Molodecky, Natalie A; Rabi, Doreen M; Ghali, William A; Barkema, Herman W; Kaplan, Gilaad G

2012-05-24

The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between living in an urban environment and the development of the Crohn's disease (CD) or ulcerative colitis (UC). A systematic literature search of MEDLINE (1950-Oct. 2009) and EMBASE (1980-Oct. 2009) was conducted to identify studies investigating the relationship between urban environment and IBD. Cohort and case-control studies were analyzed using incidence rate ratio (IRR) or odds ratio (OR) with 95 % confidence intervals (CIs), respectively. Stratified and sensitivity analyses were performed to explore heterogeneity between studies and assess effects of study quality. The search strategy retrieved 6940 unique citations and 40 studies were selected for inclusion. Of these, 25 investigated the relationship between urban environment and UC and 30 investigated this relationship with CD. Included in our analysis were 7 case-control UC studies, 9 case-control CD studies, 18 cohort UC studies and 21 cohort CD studies. Based on a random effects model, the pooled IRRs for urban compared to rural environment for UC and CD studies were 1.17 (1.03, 1.32) and 1.42 (1.26, 1.60), respectively. These associations persisted across multiple stratified and sensitivity analyses exploring clinical and study quality factors. Heterogeneity was observed in the cohort studies for both UC and CD, whereas statistically significant heterogeneity was not observed for the case-control studies. A positive association between urban environment and both CD and UC was found. Heterogeneity may be explained by differences in study design and quality factors.

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…

Profiles of rural longitudinal integrated clerkship students: a descriptive study of six consecutive student cohorts *.

PubMed

Brooks, Kathleen D; Eley, Diann S; Zink, Therese

2014-02-01

Medical schools worldwide are challenged to address the rural primary care workforce shortage by creating community-engaged curricula to nurture student interest in rural practice. To examine the personal characteristics of six consecutive rural longitudinal integrated clerkship student cohorts to understand whom the programs attract and select and thus inform the development of such programs. A cross-sectional cohort design was used. Six cohorts (2007-2012) completed a survey on demographics and factors that influenced their choice of rural primary care. The Temperament and Character Inventory was used to measure personality. Analysis was mainly descriptive. Where appropriate univariate analysis compared variables between groups. Sample size was 205 with the majority female (61%), between 25 and 29 years (64%), single (60%) and lived longest in rural communities with populations less than 20,000 (60%). Rural lifestyle, background and desire to work in underserved areas were noted to impact rural medicine interest. Professional satisfaction, personal and professional goals and family needs had the highest impact on career decisions, and financial concerns lowest. The stability of students' personal characteristics across cohorts and the workforce outcomes of this program suggest the recruitment process successfully nurtures students who will fit well into future rural practice.

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

Markers of insulin resistance and carotid atherosclerosis. A comparison of the homeostasis model assessment and triglyceride glucose index.

PubMed

Irace, C; Carallo, C; Scavelli, F B; De Franceschi, M S; Esposito, T; Tripolino, C; Gnasso, A

2013-07-01

The present investigation was designed to test the association between carotid atherosclerosis and two simple markers of insulin resistance, i.e. HOMA-Index and TyG-Index. The study was performed in two different cohorts. In the first cohort, 330 individuals were enrolled. Blood pressure, lipids, glucose, waist and cigarette smoking were evaluated. HOMA-IR and TyG-Index were calculated as markers of prevalent hepatic and muscular insulin resistance respectively. Carotid atherosclerosis was assessed by Doppler ultrasonography. The association between cardiovascular risk factors, markers of insulin resistance and carotid atherosclerosis was assessed by multiple logistic regression analyses. In the second cohort, limited to the evaluation of TyG-Index, 1432 subjects were studied. In the first cohort, TyG-Index was significantly associated with carotid atherosclerosis in a model including age, sex, diabetes, cigarette smoking and LDL cholesterol, while HOMA-IR was not. When components of metabolic syndrome were added to the model as dichotomous variables (absent/present), TyG-Index retained its predictive power. The same result was obtained when the metabolic syndrome was added to the model (absence/presence). The association between TyG-Index and carotid atherosclerosis was confirmed in the second cohort. The present findings suggest that TyG-Index is better associated with carotid atherosclerosis than HOMA-IR. © 2013 John Wiley & Sons Ltd.

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.

Dental Caries in American Indian Toddlers after a Community-Based Beverage Intervention

PubMed Central

Maupomé, Gerardo; Karanja, Njeri; Ritenbaugh, Cheryl; Lutz, Tam; Aickin, Mikel; Becker, Thomas

2014-01-01

Objective/Setting The Toddler Overweight and Tooth decay prevention Study (TOTS) was an overweight and early childhood caries (ECC) project in the Pacific Northwest USA. It targeted American Indian (AI) toddlers from birth, to effect changes in breastfeeding and sweetened beverage consumption. Design/Intervention/Participants The intervention cohort was children born in three communities during 12 months; expectant mothers were identified through prenatal visits, and recruited by tribal coordinators. The local comparison cohorts were children in those communities who were 18–30 months at study start. A control longitudinal cohort consisted of annual samples of children aged 18–30 months in a fourth community, supplying secular trends. Outcome measures d1–2mfs was used to identify incident caries in intervention, comparison, and control cohorts after 18-to-30 months of follow-up in 2006. Results No missing or filled teeth were found. For d1t, all three intervention cohorts showed statistically significant downward intervention effects, decreases of between 0.300 and 0.631 in terms of the fraction of affected mouths. The results for d2t were similar but of smaller magnitudes, decreases of between 0.342 and 0.449; these results met the 0.05 level for significance in two of three cases. In light of an estimated secular increase in dental caries in the control site, all three intervention cohorts showed improvements in both d1t and d2t. Conclusions Simple interventions targeting sweetened beverage availability (in combination with related measures) reduced high tooth decay trends, and were both feasible and acceptable to the AI communities we studied. PMID:21305835

Combination epigenetic therapy in metastatic colorectal cancer (mCRC) with subcutaneous 5-azacitidine and entinostat: a phase 2 consortium/stand Up 2 cancer study

PubMed Central

Azad, Nilofer S.; el-Khoueiry, Anthony; Yin, Jun; Oberg, Ann L.; Flynn, Patrick; Adkins, Douglas; Sharma, Anup; Weisenberger, Daniel J.; Brown, Thomas; Medvari, Prakriti; Jones, Peter A.; Easwaran, Hariharan; Kamel, Ihab; Bahary, Nathan; Kim, George; Picus, Joel; Pitot, Henry C.; Erlichman, Charles; Donehower, Ross; Shen, Hui; Laird, Peter W.; Piekarz, Richard; Baylin, Stephen; Ahuja, Nita

2017-01-01

Purpose Therapy with demethylating agent 5-azacitidine and histone deacetylase inhibitor entinostat shows synergistic re-expression of tumor-suppressor genes and growth inhibition in colorectal (CRC) cell lines and in vivo studies. Experimental Design We conducted a phase II, multi-institutional study of the combination in metastatic CRC patients. Subcutaneous azacitidine was administered at 40 mg/m2 days 1-5 and 8-10 and entinostat was given 7 mg orally on days 3 and 10. An interim analysis indicated toxicity crossed the pre-specified safety boundary but was secondary to disease. A 2nd cohort with added eligibility restrictions was accrued: prior therapies were limited to no more than 2 or 3 (KRAS-mutated and KRAS-wildtype cancers, respectively) and <30% of liver involvement. The primary endpoint was RECIST response. Serial biopsies were performed at baseline and after 2 cycles of therapy. Results Forty-seven patients were enrolled (24:Cohort 1, 23:Cohort 2). Patients were heavily pre-treated (median prior therapies 4: Cohort 1 and 2.5: cohort 2). No responses were observed. Median progression-free survival was 1.9 months; overall survival was 5.6 and 8.3 months in Cohorts 1 and 2, respectively. Toxicity was tolerable and as expected. Unsupervised cluster analysis of serial tumor biopsies suggested greater DNA demethylation in patients with PFS above the median. Conclusion In this first trial of CRC patients with combination epigenetic therapy, we show tolerable therapy without significant clinical activity as determined by RECIST responses. Reversal of hypermethylation was seen in a subset of patients and correlated with improved PFS. PMID:28186961

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.

School Obesity Prevention Policies and Practices in Minnesota and Student Outcomes: A Longitudinal Cohort Study.

PubMed

Nanney, Marilyn S; MacLehose, Richard F; Kubik, Martha Y; Davey, Cynthia S; O'Connell, Michael J; Grannon, Katherine Y; Nelson, Toben F

2016-11-01

The School Obesity-related Policy Evaluation (ScOPE) Study uses existing public surveillance data and applies a rigorous study design to evaluate effectiveness of school policies and practices impacting student behavioral and weight outcomes. The ScOPE Study used a cohort of 50 combined junior-senior and high schools in Minnesota to evaluate the change in weight-related policy environments in 2006 and 2012 and test the effect of policy change on students attending those schools in 2007 and 2013. Exposure variables included school practices about foods and beverages available in school vending machines and school stores, physical education requirements, and intramural opportunities. Primary study outcomes were average school-level ninth grade student BMI percentile, obesity prevalence, daily servings of fruits/vegetables, and daily glasses of soda. Availability of fruits/vegetables in schools was associated with a significant increase in total daily intake among ninth grade students by 0.4 servings. Availability of soda in schools was associated with a significant increase in total daily intake among ninth grade boys by 0.5 servings. Less-healthy snack and drink availability in schools was associated with a small, significant increase (1%) in student BMI percentile at the school level. Use of a school-level longitudinal cohort study design over a 6-year period uniquely adds to the methodologic rigor of school policy and practice evaluation studies. The ScOPE Study provides marginal evidence that school policies and practices, especially those that restrict vending and school store offerings, may have small effects on weight status among ninth grade students. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Model-based adaptive phase I trial design of post-transplant decitabine maintenance in myelodysplastic syndrome.

PubMed

Han, Seunghoon; Kim, Yoo-Jin; Lee, Jongtae; Jeon, Sangil; Hong, Taegon; Park, Gab-Jin; Yoon, Jae-Ho; Yahng, Seung-Ah; Shin, Seung-Hwan; Lee, Sung-Eun; Eom, Ki-Seong; Kim, Hee-Je; Min, Chang-Ki; Lee, Seok; Yim, Dong-Seok

2015-10-23

This report focuses on the adaptive phase I trial design aimed to find the clinically applicable dose for decitabine maintenance treatment after allogeneic hematopoietic stem cell transplantation in patients with higher-risk myelodysplastic syndrome and secondary acute myeloid leukemia. The first cohort (three patients) was given the same initial daily dose of decitabine (5 mg/m(2)/day, five consecutive days with 4-week intervals). In all cohorts, the doses for Cycles 2 to 4 were individualized using pharmacokinetic-pharmacodynamic modeling and simulations. The goal of dose individualization was to determine the maximum dose for each patient at which the occurrence of grade 4 (CTC-AE) toxicities for both platelet and neutrophil counts could be avoided. The initial doses for the following cohorts were also estimated with the data from the previous cohorts in the same manner. In all but one patient (14 out of 15), neutrophil count was the dose-limiting factor throughout the cycles. In cycles where doses were individualized, the median neutrophil nadir observed was 1100/mm(3) (grade 2) and grade 4 toxicity occurred in 5.1 % of all cycles (while it occurred in 36.8 % where doses were not individualized). The initial doses estimated for cohorts 2 to 5 were 4, 5, 5.5, and 5 mg/m(2)/day, respectively. The median maintenance dose was 7 mg/m(2)/day. We determined the acceptable starting dose and individualized the maintenance dose for each patient, while minimizing the toxicity using the adaptive approach. Currently, 5 mg/m(2)/day is considered to be the most appropriate starting dose for the regimen studied. Clinicaltrials.gov NCT01277484.

Exposing College Students to Exercise: The Training Interventions and Genetics of Exercise Response (TIGER) Study

ERIC Educational Resources Information Center

Sailors, Mary H.; Jackson, Andrew S.; McFarlin, Brian K.; Turpin, Ian; Ellis, Kenneth J.; Foreyt, John P.; Hoelscher, Deanna M.; Bray, Molly S.

2010-01-01

Objective: The Training Interventions and Genetics of Exercise Response (TIGER) study is an exercise program designed to introduce sedentary college students to regular physical activity and to identify genetic factors that influence response to exercise. Participants: A multiracial/ethnic cohort (N = 1,567; 39% male), age 18 to 35 years,…

Coping and Psychological Adjustment among Mothers of Children with ASD: An Accelerated Longitudinal Study

ERIC Educational Resources Information Center

Benson, Paul R.

2014-01-01

Utilizing a cohort sequential design and multilevel modeling on a sample of 113 mothers, the effects of four coping strategies (engagement, disengagement, distraction, and cognitive reframing) on multiple measures of maternal adjustment were assessed over a 7 years period when children with autism spectrum disorders in the study were approximately…

"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)…

A Longitudinal Study Exploring Liverpool Primary Schoolchildren's Perspectives on Smoking

ERIC Educational Resources Information Center

Porcellato, Lorna; Dugdill, Lindsey; Springett, Jane

2005-01-01

A cohort study was designed to explore over 200 primary schoolchildren's (ages 4-7) perspectives on smoking in the context of their own lives and subsequently, to assess any changes in these perspectives over time. Results showed that, in general, the children had a negative disposition about the habit, which did not dissipate over the 3-year…

The Scientist and the Artist: Adaptive Dissociation within the HIV-Positive Population

ERIC Educational Resources Information Center

Lawrence, Sacha; Miller, Erin; Cross, Malcolm

2015-01-01

This paper reports on the findings of two independent qualitative studies which were conducted with HIV-positive cohort over a period of 2010-2012. Although the original studies used different qualitative designs (IPA and Grounded Theory), the authors have nevertheless sought to explore the combined utility of their findings by using a broad…

EPISODIC AIR POLLUTION IS ASSOCIATED WITH INCREASED DNA FRAGMENTATION IN HUMAN SPERM WITHOUT OTHER CHANGES IN SEMEN QUALITY

EPA Science Inventory

This study was motivated by a previous report of associations between episodes of high air pollution and alterations in semen quality in young men living in an industrial district of the Czech Republic. Using a repeated measures study design, a cohort of men from this district we...

Quantifying Attitude to Chemistry in Students at the University of the South Pacific

ERIC Educational Resources Information Center

Brown, S. J.; Sharma, B. N.; Wakeling, L.; Naiker, M.; Chandra, S.; Gopalan, R. D.; Bilimoria, V. B.

2014-01-01

The attitude towards the study of chemistry for new entrant chemistry students from a multi-national, regional, tertiary educational institution in the South Pacific was investigated using a purpose-designed diagnostic instrument. The Attitude toward the Study of Chemistry Inventory (ASCI) was used to quantify attitude in a cohort of first year…

Institutional-Level Integration of the Learning and Study Strategies Inventory (LASSI)

ERIC Educational Resources Information Center

Kwong, Theresa; Wong, Eva; Downing, Kevin

2009-01-01

Purpose: The purpose of this paper is to exhibit the integration of learning and study strategies inventory (LASSI) with the City University of Hong Kong information systems to promote teaching and learning within the university. Design/methodology/approach: From the 2006 entry cohort, all undergraduate freshmen at City University of Hong Kong are…

Study and Labour Market Effects of Graduate Students' Interaction with Work Organisations during Education: A Cohort Study

ERIC Educational Resources Information Center

Thune, Taran; Støren, Liv Anne

2015-01-01

Purpose: The purpose of this paper is to present an empirically based discussion of how cooperation between higher education institutions and work organisations (WOs) can increase graduate learning experiences and employability. Design/methodology/approach: Data are based on an electronic and mail-based graduate survey among Norwegian master's…

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:…

Sequential cohort design applying propensity score matching to analyze the comparative effectiveness of atorvastatin and simvastatin in preventing cardiovascular events.

PubMed

Helin-Salmivaara, Arja; Lavikainen, Piia; Aarnio, Emma; Huupponen, Risto; Korhonen, Maarit Jaana

2014-01-01

Sequential cohort design (SCD) applying matching for propensity scores (PS) in accrual periods has been proposed to mitigate bias caused by channeling when calendar time is a proxy for strong confounders. We studied the channeling of patients according to atorvastatin and simvastatin initiation in Finland, starting from the market introduction of atorvastatin in 1998, and explored the SCD PS approach to analyzing the comparative effectiveness of atorvastatin versus simvastatin in the prevention of cardiovascular events (CVE). Initiators of atorvastatin or simvastatin use in the 45-75-year age range in 1998-2006 were characterized by their propensity of receiving atorvastatin over simvastatin, as estimated for 17 six-month periods. Atorvastatin (10 mg) and simvastatin (20 mg) initiators were matched 1∶1 on the PS, as estimated for the whole cohort and within each period. Cox regression models were fitted conventionally, and also for the PS matched cohort and the periodically PS matched cohort, to estimate the hazard ratios (HR) for CVEs. Atorvastatin (10 mg) was associated with a 11%-12% lower incidence of CVE in comparison with simvastatin (20 mg). The HR estimates were the same for a conventional Cox model (0.88, 95% confidence interval 0.85-0.91), for the analysis in which the PS was used to match across all periods and the Cox model was adjusted for strong confounders (0.89, 0.85-0.92), and for the analysis in which PS matching was applied within sequential periods (0.88, 0.84-0.92). The HR from a traditional PS matched analysis was 0.80 (0.77-0.83). The SCD PS approach produced effect estimates similar to those obtained in matching for PS within the whole cohort and adjusting the outcome model for strong confounders, but at the cost of efficiency. A traditional PS matched analysis without further adjustment in the outcome model produced estimates further away from unity.

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.

Accelerating Mathematics Achievement Using Heterogeneous Grouping

ERIC Educational Resources Information Center

Burris, Carol Corbett; Heubert, Jay P.; Levin, Henry M.

2006-01-01

This longitudinal study examined the effects of providing an accelerated mathematics curriculum in heterogeneously grouped middle school classes in a diverse suburban school district. A quasi-experimental cohort design was used to evaluate subsequent completion of advanced high school math courses as well as academic achievement. Results showed…

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.

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

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

Educational differences in alcohol consumption and heavy drinking: An age-period-cohort perspective.

PubMed

Lui, Camillia K; Kerr, William C; Mulia, Nina; Ye, Yu

2018-05-01

Low socioeconomic status (SES) has been associated with lower alcohol consumption, but also with heavier drinking. To explain this contradictory relationship, we examined SES differences in drinking patterns from an age-period-cohort (APC) perspective. Data are from seven waves of the U.S. National Alcohol Surveys from 1979 to 2010. As a proxy for SES, educational attainment was used. Past-year alcohol volume was calculated from frequency (never-to-every day) and usual quantity (1-2, 3-4, or 5-6 drinks). Past-year frequency of heavy episodic drinking was labelled as total days of 5+ drinks. Gender-stratified APC fixed-effects models were conducted controlling for demographics and adjusting for survey design and weights. Significant APC effects by education were found, but the direction varied by alcohol measure. Education and total volume were positively associated across APC. Cross-over effects for age occurred with a positive education-heavy drinking relationship in young adulthood and negative relationship in mid-adulthood. Cohort-by-education effects showed greater heavy drinking among less educated women in 1956-60 cohort and more educated men and women in younger cohorts (post-1976). Higher SES is consistently associated with total volume across age, period, and cohort, but less consistently with heavy drinking. While there are currently significant intervention efforts to reduce heavy drinking in young adulthood, our study suggests the need for age-specific strategies targeting lower-SES groups in mid-adulthood and cohort-specific strategies for lower-SES women in the baby boomer cohort and higher-SES men and women in younger birth cohorts. Copyright © 2018 Elsevier B.V. All rights reserved.

Misclassification of Case-Control Studies in Neurosurgery and Proposed Solutions.

PubMed

Esene, Ignatius Ngene; Mbuagbaw, Lawrence; Dechambenoit, Gilbert; Reda, Wael; Kalangu, Kazadi K

2018-04-01

Case-control studies (CCS) and cohort studies (CS) are common research designs in neurosurgery. But the term case-control study is frequently misused in the neurosurgical literature, with many articles reported as CCS, even although their methodology does not respect the basic components of a CCS. We sought to estimate the extent of these discrepancies in neurosurgical literature, explore factors contributing to mislabeling, and shed some light on study design reporting. We identified 31 top-ranking pure neurosurgical journals and searched them for articles reported as CCS, either in the title or in the abstract. The articles were read to determine if they really were CCS according to STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. Article assessment was conducted in duplicate (agreement [κ statistics] = 99.82%). Two hundred and twenty-four articles met our inclusion criteria, 133 of which (59.38%) correctly labeled the case-control design, whereas 91 (40.62%) misclassified this study design. Cohort studies (CS) were the most common design mislabeled as case-control studies in 76 articles (33.93%), 57 of which (25.45%) were retrospective CS. The mislabeling of CCS impairs the appropriate indexing, classification, and sorting of evidence. Mislabeling CS for CCS leads to a downgrading of evidence as CS represent the highest level of evidence for observational studies. Odds ratios instead of relative risk are reported for these studies, resulting in a distortion of the measurement of the effect size, compounded when these are summarized in systematic reviews and pooled in meta-analyses. Many studies reported as CCS are not true CCS. Reporting guidelines should include items that ensure that studies are labeled correctly. STROBE guidelines should be implemented in assessment of observational studies. Researchers in neurosurgery need better training in research methods and terminology. We also recommend accrued vigilance from reviewers and editors. Copyright © 2018 Elsevier Inc. All rights reserved.

Dentist age, period and cohort effects on provision of dental services in Australia: 1983-84 to 2009-10.

PubMed

Ju, Xiangqun; Spencer, A John; Brennan, David S

2017-06-01

To examine age, period and cohort factors of dentists in relation to diagnostic, preventive and total dental services over time in Australia. The Longitudinal Study of Dentists' Practice Activity (LSDPA) was designed to monitor dental practice activity and service provision in Australia. Participating dentists were sampled randomly from the dental registers in Australia from 1983 to 1984, and dental services provision was collected by mailed questionnaire with a log of dental services provided over one or two typical days. The data collection has been repeated every 5 years until 2009-2010. Sample supplementation of newly registered dentists occurred at successive waves. This study focused on diagnostic, preventive and total services. The time trends in the mean rates of the services were described using a standard cohort table, and negative binomial regression was applied to estimate age, period and cohort effects. The response rates were 73%, 75%, 74%, 71%, 76% and 67% in 1983, 1988, 1993, 1998, 2003 and 2009, respectively. The mean rates of diagnostic, preventive and total services increased between 1983 and 2009 across all age groups. The period effect showed a higher rate of diagnostic (rate ratios [RR]: 1.21 in 1993 to 1.80 in 2009), preventive (RR: 1.19 in 1988 to 1.85 in 2009) and the total service (RR: 1.08 in 1988 to 1.39 in 2009) over time, compared with the reference group of 1983. Older cohorts had a lower rate, and the younger cohorts had a higher rate of diagnostic, preventive and the total number of services over the study period. The highest rate of diagnostic (RR=2.53), preventive (RR=2.44) and the total service (RR=1.52) was in those aged 25-29 years in 1983 compared with the reference group of 30-34 years in 1983. Trends in dental services provision can be associated with age, period and cohort effects. The study found the rate of diagnostic, preventive and total services increased over time. Meanwhile, an increasing rate of diagnostic, preventive and the total services was observed when moving from older cohorts to younger cohorts among Australian dentists suggesting a sustained shift towards these services into the future. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The largest survivorship and clinical outcomes study of the fixed bearing Stryker Triathlon Partial Knee Replacement - A multi-surgeon, single centre cohort study with a minimum of two years of follow-up.

PubMed

Middleton, S W F; Schranz, P J; Mandalia, V I; Toms, A D

2018-05-03

The surgical management of isolated medial compartment degenerative disease of the knee causes debate. Unicompartmental arthroplasty options include fixed and mobile bearing implant designs with fixed bearing becoming increasingly popular. We present the largest cohort of a fixed bearing single radius design, Stryker Triathlon Partial Knee Replacement (PKR). We prospectively collected demographic data and patient reported outcome measures (PROMs) on our cohort of PKR implants since its adoption in our unit, 2009 until March 2015. A total of 129 implants in 115 patients with a mean follow-up of 5.5 years (2.5 to 8.5 years) were included. There were 11 revisions at an average of 1.7 years (0.6-4.1 years), two for infection, two for mal-alignment, five for progression of disease and two for loosening. The survivorship of the implants at five years is 90%. The PKR provides good survivorship at five years and PROM scores that are equal to the largest and most popular comparable implants. There is an associated learning curve with this implant, as there is with all systems and this is reflected in our results. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

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

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

Weight Gain Reduction Among 2-Year College Students: The CHOICES RCT

PubMed Central

Lytle, Leslie A.; Laska, Melissa N.; Linde, Jennifer A.; Moe, Stacey G.; Nanney, Marilyn S.; Hannan, Peter J.; Erickson, Darin J.

2016-01-01

Introduction The young adult years have been recognized as an influential period for excess weight gain. Non-traditional students and those attending 2-year community colleges are at particularly high risk for a range of adverse weight-related outcomes. Design Choosing Healthy Options in College Environments and Settings was an RCT with students randomly assigned into a control or intervention condition after baseline assessment. The study was designed to evaluate if a 24-month weight gain prevention intervention reduces the expected increase in BMI and overweight prevalence in young adults attending 2-year colleges. Two cohorts were recruited, corresponding to the fall and spring semesters. Data collection occurred at four time points for each cohort, with baseline occurring in fall 2011 for Cohort 1 and spring 2012 for Cohort 2. The 24-month follow-up occurred in fall 2013 for Cohort 1 and spring 2014 for Cohort 2. Data analysis occurred in 2015–2016. Setting/participants This research was conducted with 441 students from three community colleges in Minnesota. Intervention The 24-month intervention began with a 1-credit college course on healthy weight behaviors. A social networking and social support website was introduced as part of the course and participation encouraged for the duration of the trial. Main outcome measures Changes in BMI, weight, body fat percentage, waist circumference, and weight status were assessed. Results Retention of the cohorts at 24 months was 83.4%. There was not a statistically significant difference in BMI between conditions at the end of the trial. However, there was a statically significant difference in the prevalence of overweight/obesity between treatment conditions at 24 months. Also, participants randomized to the intervention who were overweight or obese at baseline were more than three times as likely to transition to a healthy weight by the end of the trial as compared with control students. Conclusions The intervention was not successful in achieving BMI differences between treatment groups. However, an 8% reduction in the prevalence of overweight and obesity over time may have population-level significance. PMID:27939237

Making the nursing curriculum more inclusive for students with specific learning difficulties (SpLD): embedding specialist study skills into a core module.

PubMed

Wray, Jane; Aspland, Jo; Taghzouit, Jayne; Pace, Kerry

2013-06-01

Wray et al. (2012) found that providing specialist 'add on' study skills sessions to students with SpLD increased the likelihood of progression and earlier identification. However, 48% of students identified as 'at risk' of having a SpLD did not pursue further assessment/support, which is of concern. OBJECTIVES/DESIGN/PARTICIPANTS/SETTINGS: The study aimed to explore the impact of embedding nine study skills sessions designed for students with SpLD into the mainstream curriculum on pre-registration nursing students in one HEI in the north of England. Two cohorts (September 2009 (n=257) and February 2010 (n=127)) took part; a total of 300 students completed a student feedback questionnaire (201 from September 2009, 99 from February 2010 (response rates of 87% and 80%)). The study used an outcome evaluation approach (Watson et al., 2008) to explore the impact of the sessions using a range of measures: (i) a student feedback questionnaire, (ii) length of time from registration to first contact with Disability Services, and (iii) progression data. Overall, the sessions were received very positively, especially those on essay writing, reflection and learning techniques. Students in the study cohorts made contact with Disability Services 4-6 weeks earlier than other cohorts; referrals were also higher. Equally, students with SpLD with access to study skills had higher rates of progression (e.g. 87% in 2009) than in years with no sessions (e.g. 62% in 2008); progression rates were comparable to their non-disabled peers. Mainstreaming what had previously been a reasonable adjustment made time- and resource-savings for the institution. Such approaches to embedding are important in encouraging and retaining talented and able students. Copyright © 2012 Elsevier Ltd. All rights reserved.

Geographic variation in cancer-related imaging: Veterans Affairs health care system versus Medicare.

PubMed

McWilliams, J Michael; Dalton, Jesse B; Landrum, Mary Beth; Frakt, Austin B; Pizer, Steven D; Keating, Nancy L

2014-12-02

Geographic variations in use of medical services have been interpreted as indirect evidence of wasteful care. Less overuse of services, however, may not be reliably associated with less geographic variation. To compare average use and geographic variation in use of cancer-related imaging between fee-for-service Medicare and the Department of Veterans Affairs (VA) health care system. Observational analysis of cancer-related imaging from 2003 to 2005 using Medicare and VA utilization data linked to cancer registry data. Multilevel models, adjusted for sociodemographic and tumor characteristics, were used to estimate mean differences in annual imaging use between cohorts of Medicare and VA patients within geographic areas and variation in use across areas for each cohort. 40 hospital referral regions. Older men with lung, colorectal, or prostate cancer, including 34,475 traditional Medicare beneficiaries (Medicare cohort) and 6835 VA patients (VA cohort). Per-patient count of imaging studies for which lung, colorectal, or prostate cancer was the primary diagnosis (each study weighted by a standardized price), and a direct measure of overuse-advanced imaging for prostate cancer at low risk for metastasis. Adjusted annual use of cancer-related imaging was lower in the VA cohort than in the Medicare cohort (price-weighted count, $197 vs. $379 per patient; P < 0.001), as was annual use of advanced imaging for prostate cancer at low risk for metastasis ($41 vs. $117 per patient; P < 0.001). Geographic variation in cancer-related imaging use was similar in magnitude in the VA and Medicare cohorts. Observational study design. Use of cancer-related imaging was lower in the VA health care system than in fee-for-service Medicare, but lower use was not associated with less geographic variation. Geographic variation in service use may not be a reliable indicator of the extent of overuse. Doris Duke Charitable Foundation and Department of Veterans Affairs Office of Policy and Planning.

Sugar-sweetened beverages and weight gain in children and adults: a systematic review and meta-analysis123

PubMed Central

Pan, An; Willett, Walter C; Hu, Frank B

2013-01-01

Background: The relation between sugar-sweetened beverages (SSBs) and body weight remains controversial. Objective: We conducted a systematic review and meta-analysis to summarize the evidence in children and adults. Design: We searched PubMed, EMBASE, and Cochrane databases through March 2013 for prospective cohort studies and randomized controlled trials (RCTs) that evaluated the SSB-weight relation. Separate meta-analyses were conducted in children and adults and for cohorts and RCTs by using random- and fixed-effects models. Results: Thirty-two original articles were included in our meta-analyses: 20 in children (15 cohort studies, n = 25,745; 5 trials, n = 2772) and 12 in adults (7 cohort studies, n = 174,252; 5 trials, n = 292). In cohort studies, one daily serving increment of SSBs was associated with a 0.06 (95% CI: 0.02, 0.10) and 0.05 (95% CI: 0.03, 0.07)-unit increase in BMI in children and 0.22 kg (95% CI: 0.09, 0.34 kg) and 0.12 kg (95% CI: 0.10, 0.14 kg) weight gain in adults over 1 y in random- and fixed-effects models, respectively. RCTs in children showed reductions in BMI gain when SSBs were reduced [random and fixed effects: −0.17 (95% CI: −0.39, 0.05) and −0.12 (95% CI: −0.22, −0.2)], whereas RCTs in adults showed increases in body weight when SSBs were added (random and fixed effects: 0.85 kg; 95% CI: 0.50, 1.20 kg). Sensitivity analyses of RCTs in children showed more pronounced benefits in preventing weight gain in SSB substitution trials (compared with school-based educational programs) and among overweight children (compared with normal-weight children). Conclusion: Our systematic review and meta-analysis of prospective cohort studies and RCTs provides evidence that SSB consumption promotes weight gain in children and adults. PMID:23966427

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

Cesarean section and risk of obesity in childhood, adolescence, and early adulthood: evidence from 3 Brazilian birth cohorts123

PubMed Central

Matijasevich, Alicia; Hallal, Pedro C; Horta, Bernardo L; Barros, Aluísio J; Menezes, Ana B; Santos, Iná S; Gigante, Denise P; Victora, Cesar G

2012-01-01

Background: The number of cesarean sections (CSs) is increasing in many countries, and there are concerns about their short- and long-term effects. A recent Brazilian study showed a 58% higher prevalence of obesity in young adults born by CS than in young adults born vaginally. Because CS-born individuals do not make contact at birth with maternal vaginal and intestinal bacteria, the authors proposed that this could lead to long-term changes in the gut microbiota that could contribute to obesity. Objective: We assessed whether CS births lead to increased obesity during childhood, adolescence, and early adulthood in 3 birth cohorts. Design: We analyzed data from 3 birth-cohort studies started in 1982, 1993, and 2004 in Southern Brazil. Subjects were assessed at different ages until 23 y of age. Poisson regression was used to estimate prevalence ratios with adjustment for ≤15 socioeconomic, demographic, maternal, anthropometric, and behavioral covariates. Results: In the crude analyses, subjects born by CS had ∼50% higher prevalence of obesity at 4, 11, and 15 y of age but not at 23 y of age. After adjustment for covariates, prevalence ratios were markedly reduced and no longer significant for men or women. The only exception was an association for 4-y-old boys in the 1993 cohort, which was not observed in the other 2 cohorts or for girls. Conclusion: In these 3 birth cohorts, CSs do not seem to lead to an important increased risk of obesity during childhood, adolescence, or early adulthood. PMID:22237058

Survivorship and functional outcomes of patellofemoral arthroplasty: a systematic review.

PubMed

van der List, J P; Chawla, H; Zuiderbaan, H A; Pearle, A D

2017-08-01

Historically poor results of survivorship and functional outcomes of patellofemoral arthroplasty (PFA) have been reported in the setting of isolated patellofemoral osteoarthritis. More recently, however, fairly good results of PFA were reported, but the current status of PFA outcomes is unknown. Therefore, a systematic review was performed to assess overall PFA survivorship and functional outcomes. A search was performed using PubMed, Embase and Cochrane systems, and the registries were searched. Twenty-three cohort studies and one registry reported survivorship using Kaplan-Meier curve, while 51 cohort studies reported functional outcomes of PFA. Twelve studies were level II studies, while 45 studies were level III or IV studies. Heterogeneity was mainly seen in type of prosthesis and year the cohort started. Nine hundred revisions in 9619 PFAs were reported yielding 5-, 10-, 15- and 20-year PFA survivorships of 91.7, 83.3, 74.9 and 66.6 %, respectively, and an annual revision rate of 2.18. Functional outcomes were reported in 2587 PFAs with an overall score of 82.2 % of the maximum score. KSS and Knee Function Score were 87.5 and 81.6 %, respectively. This systematic review showed that fairly good results of PFA survivorship and functional outcomes were reported at short- and midterm follow-up in the setting of isolated patellofemoral osteoarthritis. Heterogeneity existed mainly in prosthesis design and year the cohort started. These results provide a clear overview of the current status of PFA in the setting of isolated patellofemoral osteoarthritis. IV.

Gene-Lifestyle Interactions in Complex Diseases: Design and Description of the GLACIER and VIKING Studies

PubMed Central

Kurbasic, Azra; Poveda, Alaitz; Chen, Yan; Ågren, Åsa; Engberg, Elisabeth; Hu, Frank B.; Johansson, Ingegerd; Barroso, Ines; Brändström, Anders; Hallmans, Göran; Renström, Frida; Franks, Paul W.

2014-01-01

Most complex diseases have well-established genetic and non-genetic risk factors. In some instances, these risk factors are likely to interact, whereby their joint effects convey a level of risk that is either significantly more or less than the sum of these risks. Characterizing these gene-environment interactions may help elucidate the biology of complex diseases, as well as to guide strategies for their targeted prevention. In most cases, the detection of gene-environment interactions will require sample sizes in excess of those needed to detect the marginal effects of the genetic and environmental risk factors. Although many consortia have been formed, comprising multiple diverse cohorts to detect gene-environment interactions, few robust examples of such interactions have been discovered. This may be because combining data across studies, usually through meta-analysis of summary data from the contributing cohorts, is often a statistically inefficient approach for the detection of gene-environment interactions. Ideally, single, very large and well-genotyped prospective cohorts, with validated measures of environmental risk factor and disease outcomes should be used to study interactions. The presence of strong founder effects within those cohorts might further strengthen the capacity to detect novel genetic effects and gene-environment interactions. Access to accurate genealogical data would also aid in studying the diploid nature of the human genome, such as genomic imprinting (parent-of-origin effects). Here we describe two studies from northern Sweden (the GLACIER and VIKING studies) that fulfill these characteristics. PMID:25396097

Gene-Lifestyle Interactions in Complex Diseases: Design and Description of the GLACIER and VIKING Studies.

PubMed

Kurbasic, Azra; Poveda, Alaitz; Chen, Yan; Agren, Asa; Engberg, Elisabeth; Hu, Frank B; Johansson, Ingegerd; Barroso, Ines; Brändström, Anders; Hallmans, Göran; Renström, Frida; Franks, Paul W

2014-12-01

Most complex diseases have well-established genetic and non-genetic risk factors. In some instances, these risk factors are likely to interact, whereby their joint effects convey a level of risk that is either significantly more or less than the sum of these risks. Characterizing these gene-environment interactions may help elucidate the biology of complex diseases, as well as to guide strategies for their targeted prevention. In most cases, the detection of gene-environment interactions will require sample sizes in excess of those needed to detect the marginal effects of the genetic and environmental risk factors. Although many consortia have been formed, comprising multiple diverse cohorts to detect gene-environment interactions, few robust examples of such interactions have been discovered. This may be because combining data across studies, usually through meta-analysis of summary data from the contributing cohorts, is often a statistically inefficient approach for the detection of gene-environment interactions. Ideally, single, very large and well-genotyped prospective cohorts, with validated measures of environmental risk factor and disease outcomes should be used to study interactions. The presence of strong founder effects within those cohorts might further strengthen the capacity to detect novel genetic effects and gene-environment interactions. Access to accurate genealogical data would also aid in studying the diploid nature of the human genome, such as genomic imprinting (parent-of-origin effects). Here we describe two studies from northern Sweden (the GLACIER and VIKING studies) that fulfill these characteristics.

Night work and breast cancer in women: a Swedish cohort study

PubMed Central

Åkerstedt, Torbjörn; Knutsson, Anders; Narusyte, Jurgita; Svedberg, Pia; Kecklund, Göran; Alexanderson, Kristina

2015-01-01

Objectives Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case–control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data through investigating the association between the number of years with night work and breast cancer among women. Design Cohort study of individuals exposed to night shift work in relation to incidence of breast cancer in women. Setting Individuals in the Swedish Twin registry, with follow-up in the Swedish Cancer Registry. Participants 13 656 women from the Swedish Twin Registry, with 3404 exposed to night work. Outcome measures Breast cancer from the Swedish Cancer Registry (463 cases) during a follow-up time of 12 years. Results A Cox proportional hazards regression analysis with control for a large number of confounders showed that the HR was HR=1.68 (95% CI 0.98 to 2.88) for the group with >20 years of night work. When the follow-up time was limited to ages below 60 years, those exposed >20 years showed a HR=1.77 (95% CI 1.03 to 3.04). Shorter exposure to night work showed no significant effects. Conclusions The present results, together with previous work, suggest that night work is associated with an increased risk of breast cancer in women, but only after relatively long-term exposure. PMID:25877283

Patients with alcohol use disorder: initial results from a prospective multicenter registry in the Spanish Network on Addiction Disorders. CohRTA Study.

PubMed

Sanvisens, Arantza; Zuluaga, Paola; Rivas, Inmaculada; Rubio, Gabriel; Gual, Antoni; Torrens, Marta; Short, Antoni; Álvarez, Francisco Javier; Tor, Jordi; Farré, Magí; Rodríguez de Fonseca, Fernando; Muga, Roberto

2017-07-14

The Alcohol Program of the Spanish Network on Addictive Disorders-RTA requires a longitudinal study to address different research questions related to alcoholism. The cohort study (CohRTA) focuses on patients seeking treatment for alcohol use disorder, as a multicentre, collaborative research project aimed to improve secondary prevention and early diagnosis of pathological processes associated with the disorder. multicentre cohort study in adults (>18 years) seeking their first treatment of the disorder. Patients sign an informed consent and data is collected in an online platform specifically designed for the study; patients are also requested to provide biological samples that are stored in a biobank. Baseline and prospective, socio-demographic, epidemiological, clinical and treatment data are collected. Currently there are 10 participating centres that expect to recruit more than 1,000 patients. As of December 2015, 344 patients (77% men) were included. Median age at admission was 50 years (IQR: 43-55 years). Median age at the start of alcohol consumption was 15 years (IQR: 14-18 years) and 61% of cases reported antecedents of alcohol use disorder in the family. During the 30 days prior to admission, alcohol consumption amounted to 12.5 SDU/day (IQR: 7.1-20 SDU/day), 72% of the patients were tobacco smokers and 30% currently used cocaine. Organising an open cohort of patients with alcohol use disorder may be crucial to better understand the clinical consequences of alcoholism in Spain. This cohort may potentiate quantitative and qualitative research within the Spanish Network on Addictive Disorders-RTA/RETICS. Having a well-established, representative cohort of patients will increase translational research on consequences of alcoholism in our country.

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

Retrospective Population Cohort Study on Hip Fracture Risk Associated with Zolpidem Medication

PubMed Central

Lin, Fang-Yu; Chen, Pei-Chun; Liao, Chun Hui; Hsieh, Yow-Wen; Sung, Fung-Chang

2014-01-01

Study Objective: Few studies have evaluated the hip fracture risk for zolpidem users. We assessed the risk for subjects taking zolpidem. Design: Population-based retrospective cohort study using claims data of a universal insurance system. Participants: We identified 6,978 patients newly prescribed for zolpidem in 2000-2001 age 18 y and older, and 27,848 nonusers frequency matched with sex, age, and date visiting a clinic. Measurements and Results: Both cohorts were followed up to the end of 2008 to measure the hip fracture incidence and risk, which considered factors such as sex, age, occupation, days of drug use, and osteoporosis status. The zolpidem users had a 2.23-fold higher hip fracture incidence than nonusers (3.10 versus 1.39 per 1,000 person-y). The risk increased with age for both cohorts. The elderly users had a 21-fold higher incidence than the younger users, or twofold higher than the elderly nonusers. Among 33 patients (20.4%) with hip fracture occurring during presumed medication days, which was accountable for an incidence of 1,083.0 per 1,000 person-y. Those taking the medicine for 8 days or longer had a moderately higher fracture rate than those taking it for less days (6.02 versus 4.48 per 100 person-times) with a ratio of 1.34 (95% confidence interval 0.42-4.56). Subjects with blue collar occupations were at a higher fracture risk. Conclusion: The hip fracture risk of zolpidem users is higher than that of nonusers. Fracture prevention awareness should be disseminated to the users. Citation: Lin FY; Chen PC; Liao CH; Hsieh YW; Sung FC. Retrospective population cohort study on hip fracture risk associated with zolpidem medication. SLEEP 2014;37(4):673-679. PMID:24899758

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 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

Impact of ambient air pollution on physical activity among adults: a systematic review and meta-analysis.

PubMed

An, Ruopeng; Zhang, Sheng; Ji, Mengmeng; Guan, Chenghua

2018-03-01

This study systematically reviewed literature regarding the impact of ambient air pollution on physical activity among children and adults. Keyword and reference search was conducted in PubMed and Web of Science to systematically identify articles meeting all of the following criteria - study designs: interventions or experiments, retrospective or prospective cohort studies, cross-sectional studies, and case-control studies; subjects: adults; exposures: specific air pollutants and overall air quality; outcomes: physical activity and sedentary behaviour; article types: peer-reviewed publications; and language: articles written in English. Meta-analysis was performed to estimate the pooled effect size of ambient PM 2.5 air pollution on physical inactivity. Seven studies met the inclusion criteria. Among them, six were conducted in the United States, and one was conducted in the United Kingdom. Six adopted a cross-sectional study design, and one used a prospective cohort design. Six had a sample size larger than 10,000. Specific air pollutants assessed included PM 2.5 , PM 10 , O 3 , and NO x , whereas two studies focused on overall air quality. All studies found air pollution level to be negatively associated with physical activity and positively associated with leisure-time physical inactivity. Study participants, and particularly those with respiratory disease, self-reported a reduction in outdoor activities to mitigate the detrimental impact of air pollution. Meta-analysis revealed a one unit (μg/m 3 ) increase in ambient PM 2.5 concentration to be associated with an increase in the odds of physical inactivity by 1.1% (odds ratio = 1.011; 95% confidence interval = 1.001, 1.021; p-value < .001) among US adults. Existing literature in general suggested that air pollution discouraged physical activity. Current literature predominantly adopted a cross-sectional design and focused on the United States. Future studies are warranted to implement a longitudinal study design and evaluate the impact of air pollution on physical activity in heavily polluted developing countries.

Cohort profile: LIFEWORK, a prospective cohort study on occupational and environmental risk factors and health in the Netherlands

PubMed Central

Peeters, Petra H; Korevaar, Joke C; Bueno-de-Mesquita, Bas; Verschuren, W M Monique; Verheij, Robert A; Pieterson, Inka; van Leeuwen, Flora E

2018-01-01

Purpose LIFEWORK is a large federated prospective cohort established in the Netherlands to quantify the health effects of occupational and environmental exposures. This cohort is also the Dutch contribution to the international Cohort Study of Mobile Phone Use and Health (COSMOS). In this paper, we describe the study design, ongoing data collection, baseline characteristics of participants and the repeatability of key questionnaire items. Participants 88 466 participants were enrolled in three cohort studies in 2011–2012. Exposure information was collected by a harmonised core questionnaire, or modelled based on occupational and residential histories; domains include air pollution (eg, nitrogen dioxide (NO2), particulate matter with diameter ≤2.5 µm (PM2.5)), noise, electromagnetic fields (EMF), mobile phone use, shift work and occupational chemical exposures. Chronic and subacute health outcomes are assessed by self-report and through linkage with health registries. Findings to date Participants had a median age of 51 years at baseline (range 19–87), and the majority are female (90%), with nurses being over-represented. Median exposure levels of NO2, PM2.5, EMF from base stations and noise at the participants’ home addresses at baseline were 22.9 µg/m3, 16.6 µg/m3, 0.003 mWm2 and 53.1 dB, respectively. Twenty-two per cent of participants reported to have started using a mobile phone more than 10 years prior to baseline. Repeatability for self-reported exposures was moderate to high (weighted kappa range: 0.69–1) for a subset of participants (n=237) who completed the questionnaire twice. Future plans We are actively and passively observing participants; we plan to administer a follow-up questionnaire every 4–5 years—the first follow-up will be completed in 2018—and linkage to cause-of-death and cancer registries occurs on a (bi)annual basis. This prospective cohort offers a unique, large and rich resource for research on contemporary occupational and environmental health risks and will contribute to the large international COSMOS study on mobile phone use and health. PMID:29431129

Tea consumption may decrease the risk of osteoporosis: an updated meta-analysis of observational studies.

PubMed

Guo, Ming; Qu, Hua; Xu, Lin; Shi, Da-Zhuo

2017-06-01

Several epidemiological investigations have evaluated the correlation between tea consumption and risk of osteoporosis, but the results are inconsistent. Therefore, we conducted an updated meta-analysis of observational studies to assess this association. We searched for all relevant studies including cohort, cross-sectional, and case-control studies published from database inception to July 15, 2016, using MEDLINE EMBASE, and Cochrane Library. Polled odds ratios (ORs) were calculated using the random-effect model. Fourteen articles (16 studies) that examined 138523 patients were included in this meta-analysis. Seven studies concerning bone mineral density (BMD) showed an increase in BMD with tea consumption, including 4 cross-sectional studies (OR, 0.04, 95% confidence interval [CI], 0.01-0.08) and 3 cohort studies (OR, 0.01; 95% CI, 0.01-0.01). The remaining 9 studies concerning fracture, including 6 case-control studies and 3 cohort studies, showed no association between tea consumption and osteoporotic fracture (OR, 0.86; 95% CI, 0.74-1.01). This updated meta-analysis demonstrates that tea consumption could increase BMD, but the association with osteoporotic fracture requires further investigation. Together, the results highlight the need for future, high-quality-designed clinical trials on tea consumption and osteoporosis. Copyright © 2017 Elsevier Inc. All rights reserved.

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

Medication Use Patterns, Treatment Satisfaction, and Inadequate Control of Osteoporosis Study in the Asia-Pacific Region (MUSIC OS-AP): Design of a multinational, prospective, observational study examining the impact of gastrointestinal events on osteoporosis management in postmenopausal women.

PubMed

Modi, Ankita; Ebeling, Peter R; Lee, Mel S; Min, Yong-Ki; Mithal, Ambrish; Yang, Xiaoqin; Sajjan, Shiva

2015-12-01

The burden of osteoporosis in the Asia-Pacific region is not well characterized. The Medication Use Patterns, Treatment Satisfaction, and Inadequate Control of Osteoporosis Study in the Asia-Pacific Region (MUSIC OS-AP) was designed to better understand the association of gastrointestinal events with patient-reported outcomes in postmenopausal women of this region. MUSIC OS-AP is a prospective, multinational, observational cohort study of postmenopausal women ≥ 50 years of age diagnosed with osteoporosis. The study was conducted in five Asia-Pacific countries: Australia, New Zealand, Taiwan, Korea, and India. MUSIC OS-AP has three components: a physician questionnaire, a retrospective chart review, and a prospective cohort study. The physician questionnaire investigated the role of gastrointestinal events in physicians' pharmacologic management of osteoporosis. The retrospective chart review, also completed by physicians, recorded rate of osteoporosis treatment and the types of osteoporosis medications prescribed to osteoporosis patients. The prospective cohort study investigated the associations between gastrointestinal events and patient-reported outcomes among patients taking oral medications for osteoporosis as well as reasons for non-treatment in patients who remained untreated. The prospective cohort study enrolled two groups of patients: untreated, and treated with oral osteoporosis medications. Untreated patients completed only the baseline surveys, providing information on gastrointestinal event rates, quality of life, health care resource use, and reasons for non-treatment. Treated patients, who were either new to osteoporosis medication or continuing an ongoing medication course, completed surveys at baseline and 3, 6, and 12 months post-baseline. The evaluations recorded patient characteristics, gastrointestinal events, health-related and osteoporosis-specific quality of life, health care resource use, medication adherence, and satisfaction with treatment. Physicians at 59 sites completed the physician questionnaire, and data for 300 patients from 26 sites were abstracted for the retrospective chart review. Enrollment and baseline data collection for the prospective cohort study were conducted between July 2013 and August 2014 for 301 untreated and 3287 treated patients, of whom 1416 were new users and 1871 were experienced users of oral osteoporosis medications. The results of MUSIC OS-AP will highlight the association of gastrointestinal events with patient-reported outcomes among postmenopausal women with osteoporosis and elucidate physicians' management of gastrointestinal events among this patient population in the Asia-Pacific region.

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…

Charting Early Trajectories of Executive Control with the Shape School

ERIC Educational Resources Information Center

Clark, Caron A. C.; Sheffield, Tiffany D.; Chevalier, Nicolas; Nelson, Jennifer Mize; Wiebe, Sandra A.; Espy, Kimberly Andrews

2013-01-01

Despite acknowledgement of the importance of executive control for learning and behavior, there is a dearth of research charting its developmental trajectory as it unfolds against the background of children's sociofamilial milieus. Using a prospective, cohort-sequential design, this study describes growth trajectories for inhibitory control…

Cultural Diversity Online: Student Engagement with Learning Technologies

ERIC Educational Resources Information Center

Hannon, John; D'Netto, Brian

2007-01-01

Purpose: The purpose of this research is to focus on how students from different cultural and linguistic backgrounds encounter online learning environments, and to assess the extent to which cultural factors impact on learners' engagement with online learning. Design/methodology/approach: The study explores how a culturally diverse cohort of…

Association of autoimmune Addison's disease with alleles of STAT4 and GATA3 in European cohorts.

PubMed

Mitchell, Anna L; Macarthur, Katie D R; Gan, Earn H; Baggott, Lucy E; Wolff, Anette S B; Skinningsrud, Beate; Platt, Hazel; Short, Andrea; Lobell, Anna; Kämpe, Olle; Bensing, Sophie; Betterle, Corrado; Kasperlik-Zaluska, Anna; Zurawek, Magdalena; Fichna, Marta; Kockum, Ingrid; Nordling Eriksson, Gabriel; Ekwall, Olov; Wahlberg, Jeanette; Dahlqvist, Per; Hulting, Anna-Lena; Penna-Martinez, Marissa; Meyer, Gesine; Kahles, Heinrich; Badenhoop, Klaus; Hahner, Stephanie; Quinkler, Marcus; Falorni, Alberto; Phipps-Green, Amanda; Merriman, Tony R; Ollier, William; Cordell, Heather J; Undlien, Dag; Czarnocka, Barbara; Husebye, Eystein; Pearce, Simon H S

2014-01-01

Gene variants known to contribute to Autoimmune Addison's disease (AAD) susceptibility include those at the MHC, MICA, CIITA, CTLA4, PTPN22, CYP27B1, NLRP-1 and CD274 loci. The majority of the genetic component to disease susceptibility has yet to be accounted for. To investigate the role of 19 candidate genes in AAD susceptibility in six European case-control cohorts. A sequential association study design was employed with genotyping using Sequenom iPlex technology. In phase one, 85 SNPs in 19 genes were genotyped in UK and Norwegian AAD cohorts (691 AAD, 715 controls). In phase two, 21 SNPs in 11 genes were genotyped in German, Swedish, Italian and Polish cohorts (1264 AAD, 1221 controls). In phase three, to explore association of GATA3 polymorphisms with AAD and to determine if this association extended to other autoimmune conditions, 15 SNPs in GATA3 were studied in UK and Norwegian AAD cohorts, 1195 type 1 diabetes patients from Norway, 650 rheumatoid arthritis patients from New Zealand and in 283 UK Graves' disease patients. Meta-analysis was used to compare genotype frequencies between the participating centres, allowing for heterogeneity. We report significant association with alleles of two STAT4 markers in AAD cohorts (rs4274624: P = 0.00016; rs10931481: P = 0.0007). In addition, nominal association of AAD with alleles at GATA3 was found in 3 patient cohorts and supported by meta-analysis. Association of AAD with CYP27B1 alleles was also confirmed, which replicates previous published data. Finally, nominal association was found at SNPs in both the NF-κB1 and IL23A genes in the UK and Italian cohorts respectively. Variants in the STAT4 gene, previously associated with other autoimmune conditions, confer susceptibility to AAD. Additionally, we report association of GATA3 variants with AAD: this adds to the recent report of association of GATA3 variants with rheumatoid arthritis.

Aragon workers’ health study – design and cohort description

PubMed Central

2012-01-01

Background Spain, a Mediterranean country with relatively low rates of coronary heart disease, has a high prevalence of traditional cardiovascular risk factors and is experiencing a severe epidemic of overweight/obesity. We designed the Aragon Workers’ Health Study (AWHS) to characterize the factors associated with metabolic abnormalities and subclinical atherosclerosis in a middle aged population in Spain free of clinical cardiovascular disease. The objective of this paper is to describe the study design, aims and baseline characteristics of participants in the AWHS. Methods/Design Longitudinal cohort study based on the annual health exams of 5,400 workers of a car assembly plant in Figueruelas (Zaragoza, Spain). Study participants were recruited during a standardized clinical exam in 2009–2010 (participation rate 95.6%). Study participants will undergo annual clinical exams and laboratory assays, and baseline and triennial collection of biological materials for biobanking and cardiovascular imaging exams (carotid, femoral and abdominal ultrasonography, coronary calcium score, and ankle-arm blood pressure index). Participants will be followed-up for 10 years. Results The average (SD) age, body mass index, and waist circumference were 49.3 (8.7) years, 27.7 (3.6) kg/m2 and 97.2 (9.9) cm, respectively, among males (N = 5,048), and 40.8 (11.6) years, 24.4 (3.8) kg/m2, and 81.9 (9.9) cm, among females (N = 351). The prevalence of overweight, obesity, current smoking, hypertension, hypercholesterolemia, and diabetes were 55.0, 23.1, 37.1, 40.3, 75.0, and 7.4%, respectively, among males, and 23.7, 8.3, 45.0, 12.1, 59.5, and 0.6%, respectively, among females. In the initial 587 study participants who completed all imaging exams (94.5% male), the prevalence of carotid plaque, femoral plaque, coronary calcium score >1 to 100, and coronary calcium score >100 was 30.3, 56.9, 27.0, and 8.8%, respectively. 67.7% of study participants had at least one plaque in the carotid or femoral arteries. Discussion Baseline data from the AWHS show a high prevalence of cardiovascular risk factors and of sublinical atherosclerosis. Follow-up of this cohort will allow the assessment of subclinical atherosclerosis progression and the link of disease progression to traditional and emergent risk factors. PMID:22712826

Effectiveness of adjuvant radiotherapy in patients with oropharyngeal and floor of mouth squamous cell carcinoma and concomitant histological verification of singular ipsilateral cervical lymph node metastasis (pN1-state)--a prospective multicenter randomized controlled clinical trial using a comprehensive cohort design.

PubMed

Moergel, Maximilian; Jahn-Eimermacher, Antje; Krummenauer, Frank; Reichert, Torsten E; Wagner, Wilfried; Wendt, Thomas G; Werner, Jochen A; Al-Nawas, Bilal

2009-12-23

Modern radiotherapy plays an important role in therapy of advanced head and neck carcinomas. However, no clinical studies have been published addressing the effectiveness of postoperative radiotherapy in patients with small tumor (pT1, pT2) and concomitant ipsilateral metastasis of a single lymph node (pN1), which would provide a basis for a general treatment recommendation. The present study is a non-blinded, prospective, multi-center randomized controlled trial (RCT). As the primary clinical endpoint, overall-survival in patients receiving postoperative radiation therapy vs. patients without adjuvant therapy following curative intended surgery is compared. The aim of the study is to enroll 560 adult males and females for 1:1 randomization to one of the two treatment arms (irradiation/no irradiation). Since patients with small tumor (T1/T2) but singular lymph node metastasis are rare and the amount of patients consenting to randomization is not predictable in advance, all patients rejecting randomization will be treated as preferred and enrolled in a prospective observational study (comprehensive cohort design) after giving informed consent. This observational part of the trial will be performed with maximum consistency to the treatment and observation protocol of the RCT. Because the impact of patient preference for a certain treatment option is not calculable, parallel design of RCT and observational study may provide a maximum of evidence and efficacy for evaluation of treatment outcome. Secondary clinical endpoints are as follows: incidence and time to tumor relapse (locoregional relapse, lymph node involvement and distant metastatic spread), Quality of life as reported by EORTC (QLQ-C30 with H&N 35 module), and time from operation to orofacial rehabilitation. All tumors represent a homogeneous clinical state and therefore additional investigation of protein expression levels within resection specimen may serve for establishment of surrogate parameters of patient outcome. The inherent challenges of a rare clinical condition (pN1) and two substantially different therapy arms would limit the practicality of a classical randomized study. The concept of a Comprehensive Cohort Design combines the preference of a randomized study, with the option of careful data interpretation within an observational study. ClinicalTrials.gov: NCT00964977.

The Epidemiology of Longevity and Exceptional Survival

PubMed Central

Newman, Anne B.; Murabito, Joanne M.

2013-01-01

The field of the “epidemiology of longevity” has been expanding rapidly in recent years. Several long-term cohort studies have followed older adults long enough to identify the most long-lived and to define many factors that lead to a long life span. Very long-lived people such as centenarians have been examined using case-control study designs. Both cohort and case-control studies have been the subject of genome-wide association studies that have identified genetic variants associated with longevity. With growing recognition of the importance of rare variations, family studies of longevity will be useful. Most recently, exome and whole-genome sequencing, gene expression, and epigenetic studies have been undertaken to better define functional variation and regulation of the genome. In this review, we consider how these studies are leading to a deeper understanding of the underlying biologic pathways to longevity. PMID:23372024

Intradiscal electrothermal therapy used to manage chronic discogenic low back pain: new directions and interventions.

PubMed

Wetzel, F Todd; McNally, Thomas A; Phillips, Frank M

2002-11-15

Retrospective literature review. To review the data on the clinical efficacy of intradiscal electrothermal annuloplasty found at this writing in the peer-reviewed literature to date, to discuss the methodologic strengths and flaws of the studies, to discuss the pitfalls of clinical study designs, to emphasize the need for prospective randomized studies and for increased basic science investigation. Studies published or presented at peer-reviewed societies concerning the clinical efficacy of intradiscal electrothermal annuloplasty are reviewed, including background studies on deafferentation and application of thermal energy to alter biomechanical and structural properties. A proposal for future investigations is presented. Background data from intracapsular annuloplasty highlighting the safety and efficacy of intradiscal electrothermal annuloplasty are presented. Current studies on this procedure, including those in the National Registry are reviewed. All the studies share a common study design: prospective cohort with historical or noninterventional groups used as controls. The patients reviewed are similar. All have nonradicular low back pain of at least 3 months duration, failed conservative care, normal neurologic examination, and MRI showing only nondegenerative disc disease and positive concordant discography. All the patients underwent intradiscal electrothermal annuloplasty lesion at one or two levels according to standard protocols. Follow-up evaluation was performed at various intervals up to 2 years. All the studies used data from a visual analog scale, with most using the Short Form 36 (SF-36) as outcome instruments. The reported follow-up periods for the studies ranged from 6 months to 2 years. Three published studies, one with a 6-month follow-up period and two with a 1-year follow-up period, were published in the peer-reviewed literature. Two recent reports presented to the North American Spine Society were reviewed: a study of patients on a manufacturer-sponsored registry with a 1-year follow-up period and a multicenter prospective cohort study of 75 patients in an intent-to-treat group, with a 1-year follow-up period. Using the 7-point criteria of Deyo et al, all the studies suggested a positive effect of treatment, with a decrease in visual analog scale ratings and improvement in SF-36 scales, particularly those for physical function and bodily pain. The studies published so far suggest that the pain resulting from lumbar disc disease may be diminished by intradiscal electrothermal annuloplasty. All these studies project a positive therapeutic effect. However, all the studies suffer from the same methodologic flaws. A prospective cohort design or a nonrandomized prospective design is used with a biased control. The scientific validity of various study designs is discussed, and a randomized prospective study is recommended. Additionally, more investigation into the basic science of the action of intradiscal electrothermal annuloplasty is required.

What are the defining characteristics of the most cited publications in orthognathic surgery?

PubMed

Susarla, S M; Tveit, M; Dodson, T B; Kaban, L B; Hopper, R A; Egbert, M A

2018-05-21

The purpose of this study was to identify the characteristics associated with highly cited papers in orthognathic surgery. This was a cohort study of articles published in the English-language literature from 1900 to 2017. Citation databases were searched for papers related to orthognathic surgery and the most frequently cited papers were identified. For each paper, the following variables were collected: region of origin, time-period of publication, corresponding author specialty, journal of publication, topic area, study design, and number of citations. The outcome variable was the citation index (citations per year). North American investigators published 70% of the 100 most-cited articles in orthognathic surgery. The majority of papers were from oral and maxillofacial surgeons. Frequent content areas were diagnosis, virtual planning, fixation/stability, and complications. The majority (54%) of studies were cohort or case report/series. The mean number of citations was 235.0±126.5; the mean citation index was 9.9±6.1 citations per year. Time-period, content area, and study design were associated with the citation index (all P<0.001). Time-period, content area, and study design predicted the citation index (all P≤0.009). Among frequently cited papers in orthognathic surgery, oral and maxillofacial surgeons had the highest volume of contributions. Diagnosis, treatment planning, and complications were the most common topics studied. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Virtual 3D planning of tracheostomy placement and clinical applicability of 3D cannula design: a three-step study.

PubMed

de Kleijn, Bertram J; Kraeima, Joep; Wachters, Jasper E; van der Laan, Bernard F A M; Wedman, Jan; Witjes, M J H; Halmos, Gyorgy B

2018-02-01

We aimed to investigate the potential of 3D virtual planning of tracheostomy tube placement and 3D cannula design to prevent tracheostomy complications due to inadequate cannula position. 3D models of commercially available cannula were positioned in 3D models of the airway. In study (1), a cohort that underwent tracheostomy between 2013 and 2015 was selected (n = 26). The cannula was virtually placed in the airway in the pre-operative CT scan and its position was compared to the cannula position on post-operative CT scans. In study (2), a cohort with neuromuscular disease (n = 14) was analyzed. Virtual cannula placing was performed in CT scans and tested if problems could be anticipated. Finally (3), for a patient with Duchenne muscular dystrophy and complications of conventional tracheostomy cannula, a patient-specific cannula was 3D designed, fabricated, and placed. (1) The 3D planned and post-operative tracheostomy position differed significantly. (2) Three groups of patients were identified: (A) normal anatomy; (B) abnormal anatomy, commercially available cannula fits; and (C) abnormal anatomy, custom-made cannula, may be necessary. (3) The position of the custom-designed cannula was optimal and the trachea healed. Virtual planning of the tracheostomy did not correlate with actual cannula position. Identifying patients with abnormal airway anatomy in whom commercially available cannula cannot be optimally positioned is advantageous. Patient-specific cannula design based on 3D virtualization of the airway was beneficial in a patient with abnormal airway anatomy.

Depression and anxiety predict health-related quality of life in chronic obstructive pulmonary disease: systematic review and meta-analysis.

PubMed

Blakemore, Amy; Dickens, Chris; Guthrie, Else; Bower, Peter; Kontopantelis, Evangelos; Afzal, Cara; Coventry, Peter A

2014-01-01

The causal association between depression, anxiety, and health-related quality of life (HRQoL) in chronic obstructive pulmonary disease (COPD) is unclear. We therefore conducted a systematic review of prospective cohort studies that measured depression, anxiety, and HRQoL in COPD. Electronic databases (Medline, Embase, Cumulative Index to Nursing and Allied Health Literature [CINAHL], British Nursing Index and Archive, PsycINFO and Cochrane database) were searched from inception to June 18, 2013. Studies were eligible for inclusion if they: used a nonexperimental prospective cohort design; included patients with a diagnosis of COPD confirmed by spirometry; and used validated measures of depression, anxiety, and HRQoL. Data were extracted and pooled using random effects models. Six studies were included in the systematic review; of these, three were included in the meta-analysis for depression and two were included for the meta-analysis for anxiety. Depression was significantly correlated with HRQoL at 1-year follow-up (pooled r=0.48, 95% confidence interval 0.37-0.57, P<0.001). Anxiety was also significantly correlated with HRQoL at 1-year follow-up (pooled r=0.36, 95% confidence interval 0.23-0.48, P<0.001). Anxiety and depression predict HRQoL in COPD. However, this longitudinal analysis does not show cause and effect relationships between depression and anxiety and future HRQoL. Future studies should identify psychological predictors of poor HRQoL in well designed prospective cohorts with a view to isolating the mediating role played by anxiety disorder and depression.

Effectiveness of adjuvant radiotherapy in patients with oropharyngeal and floor of mouth squamous cell carcinoma and concomitant histological verification of singular ipsilateral cervical lymph node metastasis (pN1-state) - A prospective multicenter randomized controlled clinical trial using a comprehensive cohort design

PubMed Central

2009-01-01

Background Modern radiotherapy plays an important role in therapy of advanced head and neck carcinomas. However, no clinical studies have been published addressing the effectiveness of postoperative radiotherapy in patients with small tumor (pT1, pT2) and concomitant ipsilateral metastasis of a single lymph node (pN1), which would provide a basis for a general treatment recommendation. Methods/Design The present study is a non-blinded, prospective, multi-center randomized controlled trial (RCT). As the primary clinical endpoint, overall-survival in patients receiving postoperative radiation therapy vs. patients without adjuvant therapy following curative intended surgery is compared. The aim of the study is to enroll 560 adult males and females for 1:1 randomization to one of the two treatment arms (irradiation/no irradiation). Since patients with small tumor (T1/T2) but singular lymph node metastasis are rare and the amount of patients consenting to randomization is not predictable in advance, all patients rejecting randomization will be treated as preferred and enrolled in a prospective observational study (comprehensive cohort design) after giving informed consent. This observational part of the trial will be performed with maximum consistency to the treatment and observation protocol of the RCT. Because the impact of patient preference for a certain treatment option is not calculable, parallel design of RCT and observational study may provide a maximum of evidence and efficacy for evaluation of treatment outcome. Secondary clinical endpoints are as follows: incidence and time to tumor relapse (locoregional relapse, lymph node involvement and distant metastatic spread), Quality of life as reported by EORTC (QLQ-C30 with H&N 35 module), and time from operation to orofacial rehabilitation. All tumors represent a homogeneous clinical state and therefore additional investigation of protein expression levels within resection specimen may serve for establishment of surrogate parameters of patient outcome. Conclusion The inherent challenges of a rare clinical condition (pN1) and two substantially different therapy arms would limit the practicality of a classical randomized study. The concept of a Comprehensive Cohort Design combines the preference of a randomized study, with the option of careful data interpretation within an observational study. Trial registration ClinicalTrials.gov: NCT00964977 PMID:20028566

The Generation R Study: A Review of Design, Findings to Date, and a Study of the 5-HTTLPR by Environmental Interaction from Fetal Life Onward

ERIC Educational Resources Information Center

Tiemeier, Henning; Velders, Fleur P.; Szekely, Eszter; Roza, Sabine J.; Dieleman, Gwen; Jaddoe, Vincent W. V.; Uitterlinden, Andre G.; White, Tonya J. H.; Bakermans-Kranenburg, Marian J.; Hofman, Albert; Van IJzendoorn, Marinus H.; Hudziak, James J.; Verhulst, Frank C.

2012-01-01

Objective: First, we give an overview of child psychiatric research in the Generation R Study, a population-based cohort from fetal life forward. Second, we examine within Generation R whether the functional polymorphism (5-HTTLPR) in the promoter of the serotonin transporter gene interacts with prenatal maternal chronic difficulties, prenatal…

Characteristics of At-Risk Students in NELS:88. National Education Longitudinal Study of 1988. Statistical Analysis Report. Contractor Report. NCES 92-042

ERIC Educational Resources Information Center

Kaufman, Phillip; Bradbury, Denise

1992-01-01

The National Education Longitudinal Study of 1988 (NELS:88) is a large-scale, national longitudinal study designed and sponsored by the National Center for Education Statistics (NCES), with support from other government agencies. Beginning in the spring of 1988 with a cohort of eighth graders (25,000) attending public and private schools across…

The Effects of Ability Grouping on Gifted & Talented Third, Fourth, and Fifth Grade Students in Selected South Carolina Public School Districts

ERIC Educational Resources Information Center

White, Tammy Tara

2013-01-01

This is a quantitative research study using archival data to focus on the achievement of Gifted & Talented students in two South Carolina public school districts. The researcher used an open cohort comparative research design for this study. This study attempted to find if differences in student performance existed between students labeled as…

Mammography Screening Trends: The Perspective of African American Women Born Pre/Post World War II

PubMed Central

Williams, Karen Patricia; Mabiso, Athur; Lo, Yun-Jia; Penner, Louis A.

2013-01-01

Researchers have traditionally combined aging women (aged ≥50 years) when reporting their mammography use. This may inadvertently mask important cohort effects in mammography use, which are likely to result from distinct personal life experiences and generational differences. Using the Health and Retirement Study samples of 1998, 2000, and 2004, we examined cohort differences in mammography use between African American women born before 1946 (non–baby boomers) and those born in 1946 to 1953 (baby boomers). Between 1998 and 2004, screening rates for non–baby boomers declined, while those for baby boomers remained relatively steady. Hierarchical linear modeling (HLM) analyses suggest that while screening rates decreased with age (OR, 0.957; 95% CI, 0.947–0.968) cohort effects may have partially reversed the age effect, with non–baby boomers having an increased likelihood of receiving a mammogram compared to baby boomers (OR, 1.697; 95% CI, 1.278–2.254). Because African American women are diagnosed at later stages of breast cancer, documentation of cohort differences in mammography use among older African American women is important as health care professionals design intervention programs that are maximally effective for women from different cohorts. This is particularly critical as more African American women in the baby boomer cohort become part of the aging population. PMID:20575209

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

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

Postmarket studies required by the US Food and Drug Administration for new drugs and biologics approved between 2009 and 2012: cross sectional analysis.

PubMed

Wallach, Joshua D; Egilman, Alexander C; Dhruva, Sanket S; McCarthy, Margaret E; Miller, Jennifer E; Woloshin, Steven; Schwartz, Lisa M; Ross, Joseph S

2018-05-24

To characterize postmarketing requirements for new drugs and biologics approved by the US Food and Drug Administration (FDA), and to examine rates and timeliness of registration, results reporting, and publication of required prospective cohort studies, registries, and clinical trials. Cross sectional analysis. Postmarketing requirements for all new drugs and biologics approved by the FDA between 1 January 2009 and 31 December 2012, with follow-up up to 15 November 2017. Postmarketing requirements and their characteristics known at the time of FDA approval, including FDA authority, study design, and study characteristics. Rates and timeliness of registration and results reporting on ClinicalTrials.gov and publication in peer reviewed journals of required prospective cohort studies, registries, and clinical trials. Between 2009 and 12, the FDA approved 97 new drugs and biologics for 106 indications with at least one postmarketing requirement at the time of first approval, for a total of 437 postmarketing requirements. Postmarket study descriptions were short (median word count 44 (interquartile range 29-71)) and often lacked information to determine an up to date progress (131 (30%)). 220 (50.3%) postmarketing requirements were for new animal or other studies (including pharmacokinetic studies); 134 (30.7%) were for prospective cohort studies, registries, and clinical trials; and 83 (19.0%) were for secondary analyses or follow-up studies. Of 110 clinical trials, 38 (34.5%), 44 (40.0%), 62 (56.4%), 66 (60.0%), and 98 (89.1%) did not report enough information to establish use of randomization, comparator type, allocation, outcome, and number of patients to be enrolled, respectively. Of 134 required prospective cohort studies, registries, and clinical trials, 102 (76.1%) were registered on ClinicalTrials.gov; of 50 registered and completed studies, 36 (72.0%) had reported results on ClinicalTrials.gov. Among 65 completed studies, 47 (72.3%) had either reported results or were published a median of 47 months (interquartile range 32-67) after FDA approval. 32 (68.1%) of these 47 studies did not report results publicly by the time of their original FDA report submission deadline. Postmarketing requirements for new drugs and biologics were often briefly described and did not contain enough information to characterize study designs. Approximately three quarters of postmarketing requirements for prospective cohort studies, registries, and clinical trials were registered on ClinicalTrials.gov, and nearly three quarters of completed studies reported results or were published, suggesting that at least a quarter of these required studies are not being publicly disseminated. 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.

Preclinical toxicity evaluation of a novel immunotoxin, D2C7-(scdsFv)-PE38KDEL, administered via intracerebral convection-enhanced delivery in rats.

PubMed

Bao, Xuhui; Chandramohan, Vidyalakshmi; Reynolds, Randall P; Norton, John N; Wetsel, William C; Rodriguiz, Ramona M; Aryal, Dipendra K; McLendon, Roger E; Levin, Edward D; Petry, Neil A; Zalutsky, Michael R; Burnett, Bruce K; Kuan, Chien-Tsun; Pastan, Ira H; Bigner, Darell D

2016-04-01

D2C7-(scdsFv)-PE38KDEL (D2C7-IT) is a novel immunotoxin that reacts with wild-type epidermal growth factor receptor (EGFRwt) and mutant EGFRvIII proteins overexpressed in glioblastomas. This study assessed the toxicity of intracerebral administration of D2C7-IT to support an initial Food and Drug Administration Investigational New Drug application. After the optimization of the formulation and administration, two cohorts (an acute and chronic cohort necropsied on study days 5 and 34) of Sprague-Dawley (SD) rats (four groups of 5 males and 5 females) were infused with the D2C7-IT formulation at total doses of 0, 0.05, 0.1, 0.4 μg (the acute cohort) and 0, 0.05, 0.1, 0.35 μg (the chronic cohort) for approximately 72 h by intracerebral convection-enhanced delivery using osmotic pumps. Mortality was observed in the 0.40 μg (5/10 rats) and 0.35 μg (4/10 rats) high-dose groups of each cohort. Body weight loss and abnormal behavior were only revealed in the rats treated with high doses of D2C7-IT. No dose-related effects were observed in clinical laboratory tests in either cohort. A gross pathologic examination of systemic tissues from the high-dose and control groups in both cohorts exhibited no dose-related or drug-related pathologic findings. Brain histopathology revealed the frequent occurrence of dose-related encephalomalacia, edema, and demyelination in the high-dose groups of both cohorts. In this study, the maximum tolerated dose of D2C7-IT was determined to be between 0.10 and 0.35 μg, and the no-observed-adverse-effect-level was 0.05 μg in SD rats. Both parameters were utilized to design the Phase I/II D2C7-IT clinical trial.

Associations between weather conditions during the first 45 days after feedlot arrival and daily respiratory disease risks in autumn-placed feeder cattle in the United States.

PubMed

Cernicchiaro, N; Renter, D G; White, B J; Babcock, A H; Fox, J T

2012-04-01

Data on associations between weather conditions and bovine respiratory disease (BRD) morbidity in autumn-placed feedlot cattle are sparse. The goal of our study was to quantify how different weather variables during corresponding lag periods (considering up to 7 d before the day of disease measure) were associated with daily BRD incidence during the first 45 d of the feeding period based on a post hoc analysis of existing feedlot operational data. Our study population included 1,904 cohorts of feeder cattle (representing 288,388 total cattle) that arrived to 9 US commercial feedlots during September to November in 2005 to 2007. There were 24,947 total cases of initial respiratory disease (animals diagnosed by the feedlots with BRD and subsequently treated with an antimicrobial). The mean number of BRD cases during the study period (the first 45 d after arrival) was 0.3 cases per day per cohort (range = 0 to 53.0), and cumulative BRD incidence risks ranged from 0 to 36% within cattle cohorts. Data were analyzed with a multivariable mixed-effects binomial regression model. Results indicate that several weather factors (maximum wind speed, mean wind chill temperature, and temperature change in different lag periods) were significantly (P < 0.05) associated with increased daily BRD incidence, but their effects depended on several cattle demographic factors (month of arrival, BRD risk code, BW class, and cohort size). In addition, month and year of arrival, sex of the cohort, days on feed, mean BW of the cohort at entry, predicted BRD risk designation of the cohort (high or low risk), cohort size, and the interaction between BRD risk code and arrival year were significantly (P < 0.05) associated with daily BRD incidence. Our results demonstrate that weather conditions are significantly associated with BRD risk in populations of feedlot cattle. Defining these conditions for specific cattle populations may enable cattle health managers to predict and potentially manage these effects more effectively; further, estimates of effects may contribute to the development of quantitative predictive models for this important disease syndrome.

The Tennessee Children's Respiratory Initiative: Objectives, design and recruitment results of a prospective cohort study investigating infant viral respiratory illness and the development of asthma and allergic diseases.

PubMed

Hartert, Tina V; Carroll, Kecia; Gebretsadik, Tebeb; Woodward, Kimberly; Minton, Patricia

2010-05-01

The 'attack rate' of asthma following viral lower respiratory tract infections (LRTI) is about 3-4 fold higher than that of the general population; however, the majority of children who develop viral LRTI during infancy do not develop asthma, and asthma incidence has been observed to continuously decrease with age. Thus, we do not understand how viral LRTI either predispose or serve as a marker of children to develop asthma. The Tennessee Children's Respiratory Initiative has been established as a longitudinal prospective investigation of infants and their biological mothers. The primary goals are to investigate both the acute and the long-term health consequences of varying severity and aetiology of clinically significant viral respiratory tract infections on early childhood outcomes. Over four respiratory viral seasons, 2004–2008, term, predominantly non-low weight previously healthy infants and their biological mothers were enrolled during an infant's acute viral respiratory illness.Longitudinal follow up to age 6 years is ongoing [corrected]. This report describes the study objectives, design and recruitment results of the over 650 families enrolled in this longitudinal investigation. The Tennessee Children's Respiratory Initiative is additionally unique because it is designed in parallel with a large retrospective birth cohort of over 95,000 mother-infant dyads with similar objectives to investigate the role of respiratory viral infection severity and aetiology in the development of asthma. Future reports from this cohort will help to clarify the complex relationship between infant respiratory viral infection severity, aetiology, atopic predisposition and the subsequent development of early childhood asthma and atopic diseases.

Developmental toxicity testing of monoclonal antibodies: an enhanced pre- and postnatal study design option.

PubMed

Stewart, Jane

2009-09-01

For many monoclonal antibodies (mAb), the preferred species for general and reproductive safety testing is often the cynomolgus monkey. This article describes the rationale for combining the traditional "segmented" embryofetal development study with the pre- and postnatal development (PPND) study into a single "enhanced" PPND study design in the cynomolgus monkey where a single cohort of animals is exposed throughout gestation and allowed to give birth naturally. The proposed "enhanced" PPND study design evaluates all the stages of the traditional two study design using fewer animals. It also assesses the functional consequences of mid to late gestational exposure. This is of particular relevance to the risk assessment of monoclonal antibodies where fetal exposure to maternal IgG increases as pregnancy progresses and where morphologic examination of a pre-term fetus may not be adequate to reveal the presence of adverse effects on functional development of key target organs.

Supporting Professional Learning through Teacher Educator Enquiries: An Ethnographic Insight into Developing Understandings and Changing Identities

ERIC Educational Resources Information Center

McGregor, Deb; Hooker, Barbara; Wise, David; Devlin, Linda

2010-01-01

The Educational Doctorate (EdD) at the University of Wolverhampton offers educational practitioners the opportunity to design a research enquiry based in, on or around their professional work. The cohort, reported on here, embarked upon their EdD studies during the 2007/08 academic year. This study reports on seven participants' learning…

Paternal Depression and Risk for Child Neglect in Father-Involved Families of Young Children

ERIC Educational Resources Information Center

Lee, Shawna J.; Taylor, Catherine A.; Bellamy, Jennifer L.

2012-01-01

Objective: To examine the association of paternal depression with risk for parental neglect of young children. Study design: The sample was derived from a birth cohort study of 1,089 families in which both biological parents resided in the home when the target child was 3- and 5-years old. Prospective analyses examined the contribution of paternal…

The Impact of Library Resource Utilization on Undergraduate Students' Academic Performance: A Propensity Score Matching Design

ERIC Educational Resources Information Center

Kot, Felly Chiteng; Jones, Jennifer L.

2015-01-01

This study uses three cohorts of first-time, full-time undergraduate students (N = 8,652) at a large, metropolitan, public research university to examine the impact of student use of three library resources (workstations, study rooms, and research clinics) on academic performance. To deal with self-selection bias and estimate this impact more…

Diagnostic Yield of Chromosomal Microarray Analysis in a Cohort of Patients with Autism Spectrum Disorders from a Highly Consanguineous Population

ERIC Educational Resources Information Center

Al-Mamari, Watfa; Al-Saegh, Abeer; Al-Kindy, Adila; Bruwer, Zandre; Al-Murshedi, Fathiya; Al-Thihli, Khalid

2015-01-01

Autism Spectrum Disorders are a complicated group of disorders characterized with heterogeneous genetic etiologies. The genetic investigations for this group of disorders have expanded considerably over the past decade. In our study we designed a tired approach and studied the diagnostic yield of chromosomal microarray analysis on patients…