1. From the Generation R Study Group (S.H.B., R.G., A.H., V.W.V.J., H.R.) and Departments of Public Health (S.H.B., F.J.v.L., H.R.), Epidemiology (R.G., A.H., V.W.V.J.), Pediatrics (R.G., V.W.V.J.), and Obstetrics and Gynaecology (E.A.P.S.), Erasmus Medical Centre, Rotterdam, the Netherlands.