1. Department of Public Health, University of Massachusetts, 412 Arnold House, 715 North Pleasant Street, Amherst, MA 01003.
2. Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, 412 Arnold House, 715 North Pleasant Street, Amherst, MA 01003.
3. Post-Deployment Health Epidemiology Program, Office of Patient Care Services, Department of Veterans Affairs, 810 Vermont Avenue NW (10P4Q), Washington, DC 20420.