Veterans of combat: still at risk when the battle is over.

A pproximately 2.6 million troops have served or are serving overseas as part of Operation Iraqi Freedom/ Operation New Dawn in Iraq and Operation Enduring Freedom in Afghanistan, as of September 2013. 1 There have been 6664 casualties and 51 904 wounded as of February 2014. 2 Although definitions of combat experience vary, 30% of veterans with service in Afghanistan and 71% to 86% of those serving in Iraq have participated in a firefight. 3 The rising mental health problems of returning veterans are well documented, 4 with ≤20% of returning veterans meeting diagnostic criteria for posttraumatic stress disorder (PTSD) 5 and up to 17% meeting criteria for any psychological disorder (depression, anxiety, or PTSD). 3 These mental health problems stem directly from combat, with a dose-response relationship–the more firefights the soldiers had experienced, the higher the rate of PTSD and depression. However, evidence is emerging for a role of combat in exerting not just a psychological but also a physiologic toll. Previous studies of the long-term physical consequences of combat have shown mixed results. In one prospective longitudinal study enrolling veterans shortly after World War II, those who had experienced combat were more likely to die or report physical decline over a 15-year period. 6 In the Atherosclerotic Risk in Communities study, however, no increase in coronary heart disease (CHD) was seen in combat-exposed veterans compared with those who had not seen combat or who had not served in the military. 7 Both studies included limited numbers of combat veterans, however, and in the Atherosclerotic Risk in Communities study, combat experience had occurred more than 30 years earlier, in World War II or Korea. In this issue of Circulation, Crum-Cianflone et al 8 use the Millennium Cohort Study, which enrolled >60 000 military personnel, including active duty, Reserve, and National Guard from all branches of the military, starting in 2001, to provide a definitive answer to the question. All were free of CHD at the onset of the study. Overall, approximately one quarter of the troops reported exposure to combat before (N=900) or during (n≈13 000) the study period. Self-reported CHD was evaluated in all, and record-confirmed diagnoses were evaluated in a subset of approximately one third, who remained on active duty (in whom records were thus accessible). Among the entire cohort, in a model adjusting only for demographic variables, combat exposure increased the odds of self-reported cardiovascular disease …