[1] Maastricht Univ, Care & Publ Hlth Res Inst CAPHRI, Dept Hlth Serv Res, POB 616, NL-6200 MD Maastricht, Netherlands
[2] WHO Collaborating Ctr Publ Hlth Aspects Musculoske, Liege, Belgium
[3] Univ Pittsburgh, Sch Publ Hlth, Dept Epidemiol, Pittsburgh, PA USA
[4] Ohio State Univ, Wexner Med Ctr, Div Endocrinol Diabet & Metab, Columbus, OH USA
[5] Univ Calif Davis, Sch Med, Dept Med, Sacramento, CA USA
[6] Univ Liege, Div Publ Hlth Epidemiol & Hlth Econ, Liege, Belgium
[7] Cedars Sinai Med Ctr, Los Angeles, CA USA
[8] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA USA
[9] MedStar Georgetown Univ Hosp, Dept Obstet & Gynecol & Med, Washington, DC USA