[1] Kuopio Univ Hosp, Dept Internal Med, Kuopio 70211, Finland
[2] Univ Oulu, Dept Internal Med, Oulu, Finland
[3] Natl Publ Hlth Inst, Dept Epidemiol & Hlth Promot, Helsinki, Finland
[4] Univ Tampere, Sch Publ Hlth, FIN-33101 Tampere, Finland
[5] Oulu City Hosp, Oulu, Finland
[6] Univ Helsinki, Dept Publ Hlth, Helsinki, Finland
[7] S Ostrobothnia Cent Hosp, Seinajoki, Finland
[8] Univ Kuopio, Dept Neurol & Neurosci, FIN-70211 Kuopio, Finland