The Avon Longitudinal Study of Parents and Children (ALSPAC) is an ongoing population-based prospective study designed to understand the genetic and environmental factors that influence health and development. All pregnant women identified as residing in Bristol and the surrounding areas of South West England with an expected date of delivery between April 1, 1991 and December 31, 1992 were invited to participate. Among 20,248 eligible pregnancies during 1990 to 1992, the mothers of 14,541 pregnancies (71.8%) were enrolled, with 13,988 live infants at 1 year from birth. Postnatal recruitment was conducted to further increase the enrollment rate and to improve the representativeness of the ALSPAC sample. Postnatal recruitment efforts at ages 7 to 18 years added 713 children (4.85% of overall ALSPAC sample) from 706 pregnancies yielding total of 14,701 live-born children from 15,247 enrolled pregnancies (75.3%) (Boyd et al., 2013). Please note that the study website contains details of all the data that are available through a fully searchable data dictionary at “http://www.bris.ac.uk/alspac/researchers/data-access/data-dictionary.”
