1. Department of Internal Medicine, Gent University Hospital, B-9000 Gent, Belgium
2. Department of Rehabilitation and Geriatrix — Service of Bone Diseases, Geneva University Hospital, 1211 Geneva 14, Switzerland
3. Department of Internal Medicine, AP-HP, Hôpital Pitié Salpétrière and Université Pierre et Marie Curie, 75013 Paris, France
4. Department of Internal Medicine, University of Florence, 50139 Florence, Italy
5. Department of Public Health Sciences, University of Liège, 4000 Liège, Belgium