[1] Univ Pittsburgh, Dept Epidemiol, Pittsburgh, PA 15261 USA
[2] Univ Pittsburgh, Sch Dent Med, Pittsburgh, PA 15261 USA
[3] Wake Forest Univ, J Paul Sticht Ctr Aging, Winston Salem, NC 27109 USA
[4] Natl Inst Aging, Bethesda, MD USA
[5] Kent State Univ, Dept Sociol, Kent, OH 44242 USA
[6] Univ Calif San Francisco, Prevent Sci Grp, San Francisco, CA 94143 USA
[7] Univ Pittsburgh, Dept Epidemiol & Med, Pittsburgh, PA 15261 USA