We all know that atherosclerosis, that deposition of fatty and calcified material on the inside of blood vessels, isn't good for anyone. Disconcertingly, we know that the process can start in very early childhood with fatty streaks on the inside of vessels like the aorta, the body's biggest artery. Now, as Rick and I discuss on PodMed this week, perhaps we can rest a bit on our laurels. That's because the third study of US servicemen who've died while serving in the military shows a dramatic decline in the incidence of atherosclerosis over the last several decades, as reported in the Journal of the American Medical Association.
The first study to look at atherosclerosis in servicemen was done in those who fought in the Korean war, and was reported in 1953. This study showed that 77% of servicemen killed in the war had atherosclerosis in their coronary arteries, those that supply the heart with blood. A second study on servicemen in the Vietnam war found a prevalence of 45% in the same vessels. This current study on servicemen who died of combat or unintentional injuries between October 2001 and August 2011 reports that only 8.5% had any atherosclerosis in their heart vasculature at all, with greater than 50% occlusion in one or more vessels, so-called severe disease, in 2.3%, moderate occlusion in 4.7%, and minimal in 1.5%. The total number of subjects for whom an autopsy was performed was 3832, of whom 98.3% were male, with an age range of 18 to 59 years. As Rick points out in the podcast, while none of us wish death to our servicemen, these studies demonstrate a very impressive reduction in the incidence of atherosclerosis over several decades. To what do we attribute this precipitous decline?
The authors speculate that two major categories of factors must be considered: a real decline in cigarette smoking, high blood pressure, unhealthy cholesterol levels, and diabetes among servicemen, and artifactual differences in the studies regarding what constitutes atherosclerosis. Additionally, military recruits today may be considerably healthier than conscripts in the Korean and Vietnam wars, giving rise to a bias called the 'healthy warrior' effect. While the artifacts must be considered, the data seem to indicate that efforts to modify risk factors may be bearing fruit, thus reducing the number of people with coronary artery disease.
Caution, however, is warranted given the fact that heart disease remains in the number one spot when it comes to causes of death, both domestically and in other developed nations. Obesity and diabetes are on the rise and are well-known to increase the risk of heart disease. And extrapolating from rates of atherosclerosis in servicemen to the general population seems risky at best. For now, Rick and I agree that we're glad to see this decline but aren't quite ready to say well done!
Other topics this week include the risks of transfusion in folks who've had a heart attack in Archives of Internal Medicine, recurrent atrial fibrillation after ablation to try to correct the problem in the same journal, and modifying calcium and other micronutrients in people who are undergoing dialysis doesn't reduce mortality risk in NEJM. Until next week, y'all live well.