background in the golestan cohort study that was launched to investigate the causes of esophageal cancer, a complete biospecimen bank was established for storage of collected blood, urine, hair, and nail samples. the objective of this study was to evaluate the feasibility of nail samples as a biomarker of selected trace elements status. methods thirty toenail samples were selected randomly from...

Gender differences in educational outcomes were examined in a birth cohort of over 1,000 Christchurch born children studied from the point of school entry to the age of 18. This analysis suggested three major conclusions: i) Throughout the school career of this cohort males achieved less well than females. Gender differences were evident in the results of standardised testing, teacher ratings o...

BACKGROUND Childhood socio-economic position (SEP) is associated with adult smoking status. Previous studies have investigated mediation by educational attainment. The aim of this study is to examine whether childhood psychosocial factors (cognitive ability, psychosocial adjustment and parental involvement) are important in the association between childhood SEP and adult smoking status over and...

OBJECTIVES Promoting unstructured outside play is a promising vehicle to increase children's physical activity (PA). This study investigates if factors of the social environment moderate the relationship between the perceived physical environment and outside play. STUDY DESIGN 1875 parents from the KOALA Birth Cohort Study reported on their child's outside play around age five years, and 1516...

OBJECTIVES The finding that migrants to high-income countries have lower rates of morbidity and mortality than non-migrants, controlling for socioeconomic position, is often attributed to the "healthy migrant" hypothesis, which suggests that only the healthiest individuals choose to migrate. This prospective study investigates the healthy migrant hypothesis in a cohort of British emigrants usin...

Despite the abundance of medications available for human consumption, and frequent concerns about increasing medicalization or pharmaceuticalization of everyday life, there is little research investigating medicines-use in young and middle-aged populations and discussing the implications of young people using increasing numbers of medicines and becoming pharmaceutical users over time. We use da...

BACKGROUND   Many cohort studies have been carried out that have provided information on the relationship between diet and health-related outcomes. Omission of important covariates during multivariate analysis may give rise to error due to residual confounding. A possibly important covariate is socioeconomic status (SES) as this is related to both diet and health. OBJECTIVE To determine the f...

In observational studies of the effect of an exposure on an outcome, the exposure-outcome association is usually confounded by other causes of the outcome (potential confounders). One common method to increase efficiency is to match the study on potential confounders. Matched case-control studies are relatively common and well covered by the literature. Matched cohort studies are less common bu...