[1] Univ Gothenburg, Queen Silvia Childrens Hosp, Dept Paediat, SE-41685 Gothenburg, Sweden
[2] Natl Board Hlth & Welf, Stockholm, Sweden
[3] Karolinska Inst, Dept Neurobiol Care Sci & Soc, Ctr Family & Community Med, Stockholm, Sweden
[4] Karolinska Inst, Dept Womens & Childrens Hlth, Stockholm, Sweden