1. Department of Epidemiology, UCLA Fielding School of Public Health , Los Angeles, California , USA
2. Altamed , Pico Rivera, California , USA
3. Department of Human Genetics, David Geffen School of Medicine at UCLA , Los Angeles, California , USA
4. Department of Neurology, David Geffen School of Medicine at UCLA , Los Angeles, California , USA
5. Department of Neurology, Veterans Administration Greater Los Angeles Health Care System , Los Angeles, California , USA