title: Rationales, design and recruitment for the Elfe longitudinal study.
abstract: BACKGROUND
  Many factors act simultaneously in childhood to influence health status, life chances and well being, including pre-birth influences, the environmental pollutants of early life, health status but also the social influences of family and school. A cohort study is needed to disentangle these influences and explore attribution.
  
  
  METHODS
  Elfe will be a nationally representative cohort of 20 000 children followed from birth to adulthood using a multidisciplinary approach. The cohort will be based on the INSEE Permanent Demographic Panel (EDP) established using census data and civil records. The sample size has been defined in order to match the representativeness criteria and to obtain some prevalence estimation, but also to address the research area of low exposure/rare effects. The cohort will be based on repeated surveys by face to face or phone interview (at birth and each year) as well as medical interview (at 2 years) and examination (at 6 years). Furthermore, biological samples will be taken at birth to evaluate the foetal exposition to toxic substances, environmental sensors will be placed in the child's homes. Pilot studies have been initiated in 2007 (500 children) with an overall acceptance rate of 55% and are currently under progress, the 2-year survey being carried out in October this year.
  
  
  CONCLUSIONS
  The longitudinal study will provide a unique source of data to analyse the development of children in their environment, to study the various factors interacting throughout the life course up to adulthood and to determine the impact of childhood experience on the individual's physical, psychological, social and professional development.
authors.affiliation: Département santé environnement, Institut de veille sanitaire, Saint Maurice, France. s.vandentorren@invs.sante.fr
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Vandentorren
authors.forename: Corinne
authors.initials: C
authors.lastname: Bois
authors.forename: Claudine
authors.initials: C
authors.lastname: Pirus
authors.forename: Hélène
authors.initials: H
authors.lastname: Sarter
authors.forename: Georges
authors.initials: G
authors.lastname: Salines
authors.forename: Henri
authors.initials: H
authors.lastname: Leridon
mesh_terms: D002648:Child; D002657:Child Development; D002986:Clinical Trials as Topic / Q000379:methods*; D004781:Environmental Exposure / Q000009:adverse effects*; D018876:Environmental Illness / Q000517:prevention & control*; D005602:France; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D018579:Patient Selection