1. Department of Epidemiology, School of Public Health, Boston University, Boston, Massachusetts
2. Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at UCLA, Los Angeles, California
3. Department of Health Policy and Management, UCLA Fielding School of Public Health, Los Angeles, California
4. Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, California
5. Department of Social Epidemiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
6. Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan