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The latest analysis of ancient vessels shows that plaques have long been a global — and common problem.

Although atherosclerosis is linked to many of our modern-day habits — from our fat-laden diets to our sedentary lifestyles — a study documenting hardened arteries among ancient mummies suggests that factors other than what we eat and how much we exercise may be contributing to the buildup of plaque in blood vessels.

Researchers took CT scans of 137 mummies from several locations including Egypt, Peru, southwest America and the Aleutian Islands in Alaska. Reporting in the journal Lancet, they found that over a third of the mummies had signs of likely or definite hardened arteries, and even in cases where the vessels themselves had disintegrated, the unmistakable remnants of calcified plaques that maintained the shape of these vessels remained. They found that age and time of death was positively correlated with the extent of the atherosclerosis; the older the mummy, the more likely that plaques were present.

(MORE: Scientists Uncover the First Case of Hardened Arteries in a Mummy)

Previous studies had shown similar findings, but the mummies in those analyses had enjoyed relatively high socioeconomic status and were therefore more likely to eat richer diets high in saturated fat. The current study included a more diverse population of mummies, so the evidence of disease strongly indicates that lifestyle and diet may explain only part of the more complicated process of atherosclerosis. While those from the Aleutian Islands likely ate diets high in animal fats, including blubber from whales and seals, people from Peru and the Americas probably ate a more plant-based diet that tends to lower risk of atherosclerosis.

In a statement, study author Randall Thompson of Saint Luke’s Mid America Heart Institute explained:

“We found that heart disease is a serial killer that has been stalking mankind for thousands of years. In the last century, atherosclerotic vascular disease has replaced infectious disease as the leading cause of death across the developed world. A common assumption is that the rise in levels of atherosclerosis is predominantly lifestyle-related, and that if modern humans could emulate pre-industrial or even pre-agricultural lifestyles, that atherosclerosis, or at least its clinical manifestations, would be avoided. Our findings seem to cast doubt on that assumption, and at the very least, we think they suggest that our understanding of the causes of atherosclerosis is incomplete, and that it might be somehow inherent to the process of human aging.”

In other words, a certain amount of plaque buildup may be an inevitable part of the human condition and reflect the gradual drop in efficiency of the body’s ability to break down and process fats. That would support some of the previous studies on atherosclerosis found in mummies, which led researchers to argue that since ancient Egyptians ate a healthier diet and were generally more active than modern man, they might simply be predisposed to developing clogged arteries.

While it’s not clear how much of this inherent tendency to develop plaques might be responsible for atherosclerosis, what is clear is that the current understanding is incomplete, and more studies will be needed to complete the picture. Thompson and his colleagues plan to biopsy the mummies to gain better insight into how factors such as chronic infection, genetics or inflammation play a role in developing atherosclerosis.

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