1. Ann Arbor VA Healthcare System, Ann Arbor, Michigan.
2. Department of Internal Medicine, Ann Arbor, Michigan.
3. Yojoa Community Health Systems, Cortés, Honduras.
4. University of Michigan Medical School, Ann Arbor, Michigan.
5. Department of Health Behavior and Health Education, University of Michigan School of Public Health, Ann Arbor, Michigan.
6. Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan.
7. Remedi Medical Research and Development, Pachuca, Mexico.