Rationales, design and recruitment for the Elfe longitudinal study.

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.