[1] Univ Pittsburgh, Grad Sch Publ Hlth, Dept Epidemiol, Pittsburgh, PA 15261 USA
[2] Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA
[3] NIA, Lab Epidemiol Demog & Biometry, Intramural Res Program, Bethesda, MD 20892 USA
[4] Univ Tennessee, Ctr Hlth Sci, Dept Prevent Med, Memphis, TN 38163 USA
[5] Univ Queensland, Sch Human Movement Studies, Brisbane, Qld 4072, Australia