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...

Much adult physical inactivity research ignores early-life factors from which later influences may originate. In the 1958 British birth cohort (followed from 1958 to 2008), leisure-time inactivity, defined as activity frequency of less than once a week, was assessed at ages 33, 42, and 50 years (n = 12,776). Early-life factors (at ages 0-16 years) were categorized into 3 domains (i.e., physical...

Most outcome studies of rheumatic diseases report outcomes ascertained on a single occasion. While single assessments are sufficient for terminal or irreversible outcomes, they may not be sufficiently informative if outcomes change or fluctuate over time. Consequently, longitudinal studies that measure non-terminal outcomes repeatedly afford a better understanding of disease evolution.Longitudi...

BACKGROUND Since the 1930s, the environment has become increasingly obesogenic, leading to rising rates of adiposity and socioeconomic inequalities in adiposity. Building on studies comparing body mass index (BMI) for cohorts born over a period of 20 years, we examine the social patterning of BMI and central adiposity for three cohorts born over a 40-year period. METHODS Using data from the W...

This issue of Epidemiologic Reviews on cohort studies is published five decades after the initiation of the Framingham study, one of the landmark investigations of epidemiologic research and, more generally, contemporary biomedical research. Within a few years other cohort studies—for example, of British physicians and of the atomic bomb survivors—were initiated. As follow-up of the participant...

BACKGROUND Middle ear infection is common in childhood. Despite its prevalence, there is little longitudinal evidence about the impact of ear infection, particularly its association to hearing loss. By using 6-year prospective data, we investigate the onset and impact over time of ear infection in Australian children. METHODS We analyse 4 waves of the Longitudinal Study of Australian Children...

Using data from two American and one Finnish long-term longitudinal studies, we examined continuity of general aggression from age 8 to physical aggression in early adulthood (age 21-30) and whether continuity of aggression differed by country, sex, and parent occupational status. In all samples, childhood aggression was assessed via peer nominations and early adulthood aggression via self-repo...