The French CONSTANCES population-based cohort: design, inclusion and follow-up

The CONSTANCES general-purpose cohort is intended to serve as an epidemiological research infrastructure accessible to the epidemiologic research community with a focus on occupational and social factors, and on chronic diseases and aging. CONSTANCES will also provide useful public health information to the public health authorities since it was designed as a large representative sample of the general French adult population. CONSTANCES is designed as a randomly selected representative sample of French adults aged 18–69 years at inception; 200,000 subjects will be included over a five-year period. At inclusion, the selected subjects are invited to complete questionnaires and to attend a Health Screening Center (HSC) for a comprehensive health examination. A biobank will be set up. The follow-up includes a yearly self-administered questionnaire, and a periodic visit to an HSC. Social and health data are collected from the French national databases. Data collected for participants include social and demographic characteristics, socioeconomic status, life events, behaviors, and occupational factors. The health data cover a wide spectrum: self-reported health scales, reported prevalent and incident diseases, long-term chronic diseases and hospitalizations, sick-leaves, handicaps, limitations, disabilities and injuries, healthcare utilization and services provided, and causes of death. To take into account non-participation at inclusion and attrition throughout the longitudinal follow-up, a cohort of non-participants was set up and will be followed through the same national databases as participants. Inclusion begun at the end of 2012 and more than 82,000 were already included by September 2015. A public call for nested research projects was launched.