[1] Boston Univ Sch Med, Boston, MA 02118 USA
[2] Natl Inst Arthrit & Musculoskeletal & Skin Dis, NIH, Bethesda, MD 20892 USA
[3] Univ Bristol, MRC Hlth Serv Res Collaborat, Bristol BS8 2PR, Avon, England
[4] Ctr Dis Control & Prevent, Natl Ctr Hlth Stat, Div Hlth Examinat Stat, Hyattsville, MD 20782 USA
[5] Ctr Dis Control & Prevent, Natl Ctr Chron Dis Prevent & Hlth Promot, Atlanta, GA 30341 USA
[6] Univ N Carolina, Thurston Arthrit Res Ctr, Chapel Hill, NC 27599 USA
[7] Ctr Dis Control & Prevent, Natl Ctr Hlth Stat, Div Hlth Examinat Stat, Hyattsville, MD 20782 USA
[8] Univ Calif San Francisco, Div Rheumatol, San Francisco, CA 94110 USA
[9] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94105 USA
[10] Boston Univ Sch Med, Arthrit Ctr, Boston, MA 02115 USA
[11] Univ Michigan, Ann Arbor, MI 48109 USA
[12] St Thomas Hosp, Twin Res & Genet Epidemiol Unit, London SE1 7EH, England
[13] McGill Univ, Shriners Hosp Children, Joint Dis Lab, Quebec City, PQ H3G1A6, Canada
[14] McGill Univ, Dept Surg, Quebec City, PQ H3G1A6, Canada
[15] NIH, Natl Inst Diabet & Digest & Kidney Dis, Bethesda, MD 20892 USA
[16] Columbia Univ, Orthoped Res Lab, New York, NY 10032 USA
[17] Northwestern Univ, Chicago, IL 60611 USA
[18] Univ Iowa Hosp, Dept Orthopaed, Iowa City, IA 52242 USA
[19] Indiana Univ Sch Med, Rheumatol Div, Indianapolis, IN 46202 USA
[20] Stanford Univ Sch Med, Palo Alto, CA 94304 USA