[1] Natl Inst Hlth & Welf, Dept Chron Dis Prevent, FI-00271 Helsinki, Finland
[2] Univ Helsinki, Inst Clin Med, Hosp Children & Adolescents, Helsinki, Finland
[3] Univ Helsinki, Dept Psychol, SF-00100 Helsinki, Finland
[4] Univ Helsinki, Dept Gen Practice & Primary Hlth, SF-00100 Helsinki, Finland
[5] Vasa Cent Hosp, Vaasa, Finland
[6] Univ Helsinki, Cent Hosp, Unit Gen Practice, Helsinki, Finland