[1] Univ Southampton, Southampton Gen Hosp, MRC Epidemiol Resource Ctr, Southampton SO16 6YD, Hants, England
[2] Univ Oxford, Norman Collisson Chair Musculoskeletal Sci, Oxford, England
[3] Univ Hosp Geneva, Serv Bone Dis, WHO Collaborating Ctr Osteoporosis Prevent, Geneva, Switzerland
[4] Univ Liege, Dept Publ Hlth Sci, Liege, Belgium