1. Department of Surgery, Larner College of Medicine, University of Vermont, Burlington, VT, USA;
2. Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, VT, USA;
3. Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark;
4. Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA;
5. Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA;
6. Department of Psychiatry, Boston University School of Public Health, Boston, MA, USA;
7. National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA