Prevalence of and Risk Factors for Autopsy-Determined Atherosclerosis Among US Service Members, 2001-2011

Study Questions:

What is the current prevalence of coronary and aortic atherosclerosis in the US armed forces?

Methods:

This was a cross-sectional study of all US service members who died of combat or unintentional injuries in support of Operations Enduring Freedom and Iraqi Freedom/New Dawn between October 2001 and August 2011, and whose cardiovascular autopsy reports were available at the time of data collection in January 2012. Prevalence of atherosclerosis was analyzed by various demographic characteristics and medical history. Classifications of coronary atherosclerosis severity were determined prior to data analysis and designed to provide consistency with previous military studies: minimal (fatty streaking only), moderate (10%-49% luminal narrowing of ≥1 vessel), and severe (≥50% narrowing of ≥1 vessel).

Results:

Of the 3,832 service members included in the analysis, the mean age was 25.9 years (range, 18-59 years) and 98.3% were male. The overall prevalence of coronary or aortic atherosclerosis was 12.1% (95% confidence interval [CI], 11.1%-13.1%). The prevalence of any coronary atherosclerosis was 8.5% (95% CI, 7.6%-9.4%); severe coronary atherosclerosis was present in 2.3% (95% CI, 1.8%-2.7%), moderate in 4.7% (95% CI, 4.0%-5.3%), and minimal in 1.5% (95% CI, 1.1%-1.9%). Age had the strongest association with prevalent atherosclerosis. Those ages 40 years and older had about 7 times the prevalence of disease as compared with those ages 24 years and younger (45.9% vs. 6.6%). Service members with atherosclerosis were significantly older (mean [standard deviation] age, 30.5 [8.1] years) than those without (age 25.3 [5.6] years; p < 0.001). Comparing atherosclerosis prevalence among those with no cardiovascular risk factor diagnoses (11.1%), there was a greater prevalence among those with a diagnosis of dyslipidemia (50.0% with age-adjusted prevalence ratio [PR], 2.09), hypertension (43.6% with age-adjusted PR, 1.88) and obesity (22.3% with age-adjusted PR, 1.47). Smoking (14.1% prevalence) was not significantly associated with a higher prevalence of atherosclerosis (age-adjusted PR, 1.12). Lower education level and higher military entrance body mass index were significantly associated with prevalent atherosclerosis, after adjusting for age.

Conclusions:

Among deployed US service members who died of combat or unintentional injuries and received autopsies, the prevalence of atherosclerosis varied by age and cardiovascular risk factors.

Perspective:

While there may be some technical bias for assessing atherosclerosis as well as the concept of the ‘healthy warrior’ at this time, there was a marked reduction in the prevalence of any and severe coronary atherosclerosis comparing similar studies in the Korean War (1953; any 77% and severe 15%), the Vietnam War (1971; 45% and 5%) and the Gulf Wars from 2001-2011 (2012; 8.5% and 2.3%). The findings are consistent with the decrease in prevalence of ischemic heart disease in the United States, and further support lifestyle interventions for atherosclerosis prevention in young men.

Keywords: Coronary Artery Disease, Myocardial Ischemia, Atherosclerosis, Risk Factors, Autopsy, Korean War, Dyslipidemias, Body Mass Index, Cardiovascular Diseases, Obesity, Military Personnel, Hypertension, United States, Vietnam


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