[1] Natl Inst Hlth & Welf, Dept Chron Dis Prevent, FI-00271 Helsinki, Finland
[2] Natl Inst Hlth & Welf, Dept Chron Dis Prevent, Turku, Finland
[3] Univ Helsinki, Dept Publ Hlth, Helsinki, Finland
[4] Univ Helsinki, Dept Gen Practice & Primary Hlth Care, Helsinki, Finland
[5] Univ Helsinki, Cent Hosp, Unit Gen Practice, Helsinki, Finland
[6] Folkhalsan Res Ctr, Helsinki, Finland
[7] Vasa Cent Hosp, Vaasa, Finland