[1] Free Univ Brussels, Acad Ziekenhuis, Dept Orthopaed & Traumatol, B-1090 Brussels, Belgium
[2] European Inst Oncol, Div Epidemiol & Biostat, Milan, Italy
[3] Ctr Res Epidemiol & Hlth Informat Syst Luxembourg, Luxembourg, Luxembourg
[4] Inst Jules Bordet, Unit Epidemiol & Prevent Canc, B-1000 Brussels, Belgium
[5] Katholieke Univ Leuven, Ctr Metab Bone Dis, Louvain, Belgium
[6] Katholieke Univ Leuven, Div Geriatr Med, Louvain, Belgium