[1] Univ Bergen, Cardiol Sect, Dept Clin Sci, N-5020 Bergen, Norway
[2] Univ Bergen, Cardiol Sect, Dept Global Publ Hlth & Primary Care, N-5020 Bergen, Norway
[3] Norwegian Inst Publ Hlth, Dept Hlth Registries, Bergen, Norway
[4] Norwegian Inst Publ Hlth, Div Epidemiol, Bergen, Norway
[5] Haukeland Hosp, Dept Heart Dis, N-5021 Bergen, Norway