[1] Natl Publ Hlth Inst, Dept Hlth Promot & Chron Dis Prevent, FIN-00300 Helsinki, Finland
[2] Natl Publ Hlth Inst, Dept Hlth & Funct Capac, FIN-00300 Helsinki, Finland
[3] Univ Helsinki, Dept Publ Hlth, FIN-00014 Helsinki, Finland
[4] Helsinki Univ Hosp, Dept Obstet & Gynaecol, FIN-00290 Helsinki, Finland
[5] S Ostrobothnia Cent Hosp, Seinajoki 60220, Finland