[1] Univ Calif Los Angeles, Dept Epidemiol, Fielding Sch Publ Hlth, Los Angeles, CA USA
[2] Univ Aarhus, Epidemiol Sect, Dept Publ Hlth, DK-8000 Aarhus C, Denmark
[3] Univ Calif Los Angeles, Dept Neurol, Geffen Sch Med, Los Angeles, CA 90024 USA
[4] Univ Calif Los Angeles, Calif Ctr Populat Res, Los Angeles, CA USA
[5] Univ Calif Los Angeles, Ctr Hlth Policy Res, Los Angeles, CA USA