1. Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, U.K
2. Department of Endocrinology, Peninsula Medical School, Plymouth, U.K
3. Department of Social Medicine, University of Bristol, Bristol, U.K
4. Avon Longitudinal Study of Parents and Children (ALSPAC) Study Team, University of Bristol, Bristol, U.K
5. Department of Medical Sciences, Uppsala University, Uppsala, Sweden
6. London School of Hygiene and Tropical Medicine, London, U.K