[1] Folkhalsan Res Ctr, Helsinki, Finland
[2] Univ Helsinki, Dept Gen Practice & Primary Hlth Care, POB 20, FIN-00014 Helsinki, Finland
[3] Helsinki Univ Hosp, Helsinki, Finland
[4] Kuopio Univ Hosp, Primary Hlth Care Unit, Kuopio, Finland
[5] Natl Inst Hlth & Welf, Dept Publ Hlth Solut, Unit Chron Dis Prevent, Helsinki, Finland
[6] Helsinki Univ Hosp, Childrens Hosp, Helsinki, Finland
[7] Univ Helsinki, Helsinki, Finland
[8] Oulu Univ Hosp, MRC Oulu, PEDEGO Res Unit, Oulu, Finland
[9] Univ Oulu, Oulu, Finland
[10] Univ Jyvaskyla, Gerontol Res Ctr, Jyvaskyla, Finland
[11] Univ Jyvaskyla, Fac Sport & Hlth Sci, Jyvaskyla, Finland
[12] Natl Univ Singapore, Yong Loo Lin Sch Med, Dept Obstet & Gynecol, Singapore, Singapore
[13] Agcy Sci Technol & Res, Singapore Inst Clin Sci, Singapore, Singapore