[1] Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden
[2] Univ Iceland, Fac Med, Ctr Publ Hlth Sci, Reykjavik, Iceland
[3] Erasmus MC Univ Med Ctr, Dept Epidemiol, Rotterdam, Netherlands
[4] Erasmus MC Univ Med Ctr, Dept Child & Adolescent Psychiat, Rotterdam, Netherlands
[5] Univ Orebro, Fac Med & Hlth, Clin Epidemiol & Biostat, SE-70182 Orebro, Sweden
[6] Karolinska Univ Hosp, Lung & Allergy Unit, Astrid Lindgren Childrens Hosp, Stockholm, Sweden