1. Department of Kinesiology and Health Sciences, Columbus State University , Columbus, Georgia, USA
2. Department of Epidemiology, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
3. Department of Psychiatry, Columbia University College of Physicians and Surgeons, and The New York State Psychiatric Institute , New York, New York , USA
4. Department of Behavioral and Community Health Sciences, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
5. California Pacific Medical Center Research Institute , San Francisco, California , USA
6. Department of Epidemiology and Biostatistics, University of California , San Francisco, California , USA