[1] Univ Calif Irvine, Coll Med, Dept Med, Div Epidemiol, Irvine, CA 92697 USA
[2] San Diego State Univ, Grad Sch Publ Hlth, Div Occupat & Environm Hlth, San Diego, CA 92182 USA
[3] Univ Calif Irvine, Coll Med, Dept Community & Environm Med, Irvine, CA 92717 USA
[4] Univ Washington, Dept Environm & Occupat Hlth Sci, Seattle, WA 98195 USA