That's a Wrap: Atherosclerosis Not Only a Modern Disease
Atherosclerosis is often considered a hazard of modern life and we long for the simpler, healthier lifestyles of old. However, new evidence suggests we may be idealizing the past, at least insofar as it applies to ancient civilizations; data suggest life back then wasn’t quite the idyllic setting for cardiovascular (CV) health we assumed it to be.
In fact, data from the HORUS study released in 2011 indicated that a little less than half of a group of ancient Egyptian mummies had identifiable vascular calcification. New data from the expanded HORUS study, presented on March 10 at ACC.13, indicated that atherosclerosis existed even beyond the borders of Egypt. About one-third of all mummies examined from four geographical populations, including a group of hunter-gatherers, had probable or definite atherosclerosis.
"Commonly, we think of atherosclerosis as a consequence of modern lifestyles, mainly because it has increased in developing countries as they become more westernized," said ACC President-Elect John Gordon Harold, MD, MACC. "The data from the HORUS study of four ancient populations suggests a missing link in our understanding of heart disease, and we may not be so different from these ancient civilizations."
35 Centuries Later
The HORUS study started when cardiologists toured the Egyptian National Museum of Antiquities in Cairo during a medical conference in 2008. They noticed the nameplate of the pharoah Merenptah, who ruled from 1213 B.C. to 1203 B.C. The biographical information noted that Merenptah died at roughly age 60 of atherosclerosis. That seemed like a surprising diagnosis for a time thought to be much less likely to produce atherosclerosis.
Working closely with the museum, an international team of researchers performed whole-body, multi-slice computed tomography (CT) scanning on 52 ancient Egyptian mummies from the Middle Kingdom to the Greco-Roman period, a timespan of more than 2,200 years. The investigators sought to identify CV structures and arterial calcifications.
Images were interpreted by consensus reading of seven imaging physicians and demographic data were determined from historical and museum records. Age at the time of death was estimated from the CT skeletal evaluation.
Of the mummies examined, 44 had identifiable vascular tissue. It was not possible to image all vascular beds in each mummy due to incomplete preservation and variable embalming techniques that differed in terms of the removal of vessels or organs. The aorta, iliac, and peripheral arteries were generally better preserved and available than the coronaries and carotids.
Overall, 45 percent of the mummies with identifiable CV structures showed vascular calcification. Given that the examination was being performed up to 35 centuries after the subjects had died, it was remarkable that 20 of these mummies had either definite atherosclerosis (defined as calcification within the wall of an identifiable artery, n=12) or probable atherosclerosis (defined as calcifications along the expected course of an artery, n=8). The mummies with definite or probable atherosclerosis were about 11 years older at the time of death than the mummies with CV tissue but no atherosclerosis (mean age 45.1 vs 34.5; p<0.002).
Thus, vascular calcification affected arteries in many regions of the body in ancient Egyptians, just as it does in contemporary humans.
Worldwide Mummy Analysis
Now the HORUS study has expanded, obtaining whole body CT scans of 137 mummies from four populations spanning a 3,800 year time horizon, from multiple locations in ancient Egypt, Peru and North America.
Although the results of the original study were surprising, the researchers wanted to examine ancient remains of people different from those in Egypt, where the culture or lifestyle might have lent itself to atherogenesis. In other words, if the original analysis looked at the hearts of the 1 percent, this second study was in the everyday man – the 99 percent.
Again, mummies underwent whole body CT scanning. Fifty-two of the 76 Egyptians mummies were reported on the first analysis. The overall rate of probably or definite atherosclerosis was found in 34 percent of the mummies. The rate of atherosclerosis varied by geographical region, but was still found in all: ancient Egyptians (29 of 76; 38 percent), early intermediate to late horizon people in present day Peru (13 of 51; 25 percent), Ancestral Puebloan in southwest American (two of five; 40 percent) and Unangan people from the Aleutian Island of modern day Alaska (three of five; 60 percent).
"Assumed to be a modern disease, the presence of atherosclerosis in these disparate populations suggests the possibility of a more basic predisposition to the disease and that atherosclerosis is an inherent component of human aging with other causes or risk factors that need to be further elucidated," Dr. Harold said.
Similar to the initial study, associations between age and atherosclerosis were identified. The mean age of death among those with atherosclerosis was more than 10 years older than that of those without atherosclerosis (43 years vs. 32 years; p < 0.0001). In addition, an increasing mean age at death was associated with an increase in the number of arterial beds involved in disease (three to five beds: 44 years vs. one to two beds: 42 years vs. no atherosclerosis: 32 years; p < 0.0001).
Each decade increase in age was associated with a 69 percent increase in atherosclerosis severity (95 percent CI, 1.19-2.40). When these data were isolated to just those with definite atherosclerosis, the association remained with a 64 percent increase in atherosclerosis severity per decade of life (95 percent, CI, 1.14-2.35).
Atherosclerosis was most commonly found in the aorta (20 percent), but was also identified in the iliofemoral artery (18 percent), popliteal or tibial arteries (18 percent), carotid artery (12 percent) and coronary artery (4 percent).
"Physicians have blamed fast food, lack of exercise, smoking and lifestyle factors of modern life as explaining our predisposition to heart disease," Dr. Harold said. "We have to look beyond modern risk factors to fully understand atherosclerotic heart disease."
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