Four-thousand-year-old mummies have cholesterol buildup in their arteries, suggesting that heart disease was likely more common in ancient times than once thought, according to a new study.

Prior studies have examined arterial calcium accumulation in mummified human hearts and arteries using dissection and X-ray computed tomography (CT) scanning. But these studies showed damage that only occurs in the later stages of heart disease and presents an incomplete picture of how widespread heart disease risk may have been thousands of years ago.

Now, researchers have analyzed arteries from five ancient mummies from South America and ancient Egypt, detecting an earlier stage of atherosclerosis — when plaque collects on artery walls and restricts blood flow.

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"I've been looking at the pattern of heart disease in populations for over 20 years," said lead study author Mohammad Madjid, an assistant professor of cardiovascular medicine at McGovern Medical School, part of the University of Texas Health Science Center at Houston."Over time, the question that came to my mind was: Is it a disease of the modern day, or is it some process that is inherent to humans, irrespective of modern life?"

To answer that question, Madjid and his colleagues collected arterial samples from five mummies dating from 2000 B.C. to A.D. 1000; the remains represented three men and two women, who were between 18 years old and 60 years old. The scientists scanned tiny sections of arteries, which were just a few centimeters in length, Madjid told Live Science. Their analysis revealed lesions from accumulated cholesterol, precursors to the plaque buildup that blocks arteries and leads to heart attacks. This is the first evidence of earlier-stage lesions in mummies from different parts of the world, the study authors wrote.

Earlier studies found later-stage arterial plaque in mummies from Greenland dating to 500 years ago, and in Egyptian mummies dating to more than 3,000 years ago. And CT scans of the mummified Ice Age hunter Ötzi revealed in 2018 that he was a likely candidate for a heart attack, with three sections of hardened plaque near his heart, Live Science previously reported.

Cholesterol deposits on arterial walls "essentially are the body's wound healing mechanism gone wrong," Madjid explained. "It's in response to multiple traumas [such as] infections, high cholesterol, exposure to smoke and other issues that can damage the inner lining of arteries, called the endothelium," he said.

The body's inflammatory response is a normal part of wound healing, but damaged arterial walls are susceptible to buildup of white blood cells, which can lead to accumulations of cholesterol. This buildup first shows up as streaks and lesions, and can later thicken enough to block arterial blood flow, Madjid said.

"These are very well-known processes that we find under the microscope in the modern age, we now have seen similar patterns in our ancestors, too," he said. "It looks like this inflammatory process and the response is an inherent part of our life."

The findings were published online in the October 2019 issue of the American Heart Journal.

Originally published on Live Science.