1. National Public Health Institute (E.K., H.Y., T.F., J.E.), 00300 Helsinki, Finland;
2. Hospital for Children and Adolescents (E.K., S.A.), Helsinki University Central Hospital, 00029 HUS, Helsinki, Finland;
3. Medical Research Council Environmental Epidemiology Unit (E.K., C.O., D.J.P.B.), Southampton General Hospital, Southampton SO16 6YD, United Kingdom
4. Finnish Genome Centre (A.R., J.K.), University of Helsinki, Helsinki, Finland;
5. Department of Biosciences at Novum and Clinical Research Centre (J.K.), Karolinska Institute, 141 86 Stockholm, Sweden;