[1] Dartmouth Med Sch, Dept Med, Hanover, NH USA
[2] Dartmouth Med Sch, Dept Community & Family Med, Hanover, NH USA
[3] Stockholm Cty Council, Div Epidemiol, Stockholm, Sweden
[4] Karolinska Hosp, Dept Orthopaed, S-10401 Stockholm, Sweden
[5] Karolinska Inst, Dept Med Epidemiol, Stockholm, Sweden
[6] Int Agcy Res Canc, Unit Field & & Intervent Studies, F-69372 Lyon, France
[7] Univ Uppsala Hosp, Dept Orthopaed, Uppsala, Sweden
[8] Univ Uppsala Hosp, Dept Internal Med, S-75185 Uppsala, Sweden