[1] Univ Minnesota, Sch Publ Hlth, Dept Med, Minneapolis, MN USA
[2] Univ Minnesota, Sch Publ Hlth, Div Epidemiol & Community Hlth, Minneapolis, MN USA
[3] VA Hlth Care Syst, Ctr Chron Dis Outcomes Res, Minneapolis, MN USA
[4] Calif Pacific Med Ctr, Res Inst, San Francisco, CA USA
[5] VA Hlth Care Syst, Geriatr Res Educ & Clin Ctr, Minneapolis, MN USA
[6] Univ Alabama Birmingham, Dept Epidemiol, Birmingham, AL USA
[7] Univ Pittsburgh, Grad Sch Publ Hlth, Dept Epidemiol, Pittsburgh, PA USA
[8] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA
[9] Univ Calif San Francisco, Dept Med, San Francisco, CA USA
[10] Univ Alabama Birmingham, Dept Med, Birmingham, AL 35294 USA
[11] Oregon Hlth & Sci Univ, Bone & Mineral Unit, Portland, OR 97201 USA
[12] Univ Calif San Diego, Dept Family Med & Publ Hlth, La Jolla, CA 92093 USA
[13] Oregon Hlth & Sci Univ, Dept Orthopaed & Rehabil, Portland, OR 97201 USA
[14] Univ Alabama Birmingham, Div Prevent Med, Birmingham, AL USA
[15] Pk Nicollet Clin, St Louis Pk, MN USA
[16] Univ Minnesota, Sch Publ Hlth, Div Hlth Policy & Management, Minneapolis, MN USA