[1] Univ Liege, WHO Collaborating Ctr Publ Hlth Aspects Musculo sk, Div Publ Hlth Epidemiol & Hlth Econ, Liege, Belgium
[2] Univ Milan, Dept Clin Sci & Community Hlth, Milan, Italy
[3] IRCCS Ist Clin Sci Maugeri, Geriatr Unit, Milan, Italy
[4] Hosp Univ Ramon & Cajal IRYCIS, Serv Geriatr, Madrid, Spain
[5] Univ Liege, WHO Collaborating Ctr Publ Hlth Aspects Musculo Sk, Div Publ Hlth Epidemiol & Hlth Econ, Ave Hippocrate13, CHU Bat B23, Liege B-4000, Belgium