[1] Univ Calif San Francisco, Dept Med, Sch Med, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Sch Med, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA
[3] Univ Minnesota, Sch Publ Hlth, Div Epidemiol & Community Hlth, Minneapolis, MN USA
[4] Univ Washington, Sch Publ Hlth, Dept Epidemiol, Seattle, WA 98195 USA
[5] Univ Washington, Dept Med, Seattle, WA USA
[6] Univ Minnesota, Sch Med, Dept Lab Med & Pathol, Minneapolis, MN 55455 USA
[7] Wake Forest Univ, Bowman Gray Sch Med, Dept Radiol, Winston Salem, NC USA