WASHINGTON/LONDON – It turns out that our ancestors — meat-eating or tuber-loving, Mediterranean or Arctic, roaming or sedentary — all could have used some medicine to help prevent heart disease.
A new study of 137 mummified bodies, some as old as 3,500 years, found a high prevalence of hardening of the arteries, which often presages heart attack or stroke.
The condition was common in four groups — ancient Egyptians, pre-Columbian people in Peru and Utah, and 19th-century Alaska natives — with different diets and ways of life.
“It kind of casts doubt on — makes us pause and think about — whether we understand risk factors (for cardiovascular disease) as well as we thought we did,” said Randall Thompson, a physician at the University of Missouri who headed a research team of 19 cardiologists, radiologists and anthropologists.
“Probable or definite” atherosclerosis was evident in 34 percent of the mummies. Only 4 percent, however, had atherosclerosis in the coronary arteries, where it can cause heart attacks. The condition was more common in people who died in middle and old age, but was also seen frequently in those dying in their 30s.
The prevalence of diseased arteries in the mummies is not very different from that seen today, leading the researchers to conclude that cardiovascular disease “is an inherent component of human aging and not characteristic of any specific diet or lifestyle.”
Thompson, who is a practicing cardiologist, said he was especially surprised by how common atherosclerosis was in people whose diets are viewed in some quarters as especially healthful.
Thompson said there could be unknown factors that contributed to the mummies’ narrowed arteries. He said the ancestral Puebloans, who lived in underground caves in modern-day Colorado and Utah, used fire for heat and cooking. That produced a lot of smoke. “They were breathing in a lot of smoke and that could have had the same effect as cigarettes,” he said.
The 51 ancient Peruvians, who in life presumably ate a lot of beans and complex carbohydrates such as sweet potatoes and manioc, had atherosclerosis in 25 percent of their mummies. Three of the five Aleutian hunter-gatherers, who ate a “paleo diet” high in meat and devoid of sweets and grains, showed atherosclerosis. One woman who died in her late 40s had “the kind of disease we see in people with bypass surgery,” he said.
“I think we’ll have a debate about just how important diet is and what we ought to be communicating to patients,” he added. “A healthy diet and lifestyle may lead to less disease, but it doesn’t prevent disease altogether.”
Many previous studies have sought to diagnose disease in ancient preserved human remains.
One study published two years ago found atherosclerosis common in Egyptian mummies. Whether that represented what was happening elsewhere in the ancient world, or was only an occupational hazard of butter-slurping layabout priests and pharaohs, was unknown.
The new study, presented Sunday at the American College of Cardiology meeting in San Francisco and published online by the Lancet, appears to be the first to compare findings from many different mummy populations.
Heart disease epidemiologists were quick to say the study should not undermine evidence from thousands of studies suggesting that atherosclerotic cardiovascular disease is mostly a 20th-century problem.
“Heart attack and stroke are modern plagues that have increased and then steadily decreased over modern times,” said Henry Blackburn of the University of Minnesota, who has documented wildly varying rates of heart attack in different countries with different diets.
Atherosclerosis is a process in which the wall of an artery fills with fat, fibrous tissue and, in later stages, grains of calcium. If the “plaque” gets large enough, it limits the flow of blood. When that happens and tissue downstream dies, the result is a heart attack or stroke.
The researchers used CT scanners to detect calcium in arteries. They looked in the aorta, which is the body’s main arterial trunk; the coronary arteries of the heart; the carotid arteries of the neck; and the arteries of the thigh and the lower leg.
When calcium was present, they concluded the person had atherosclerosis — a diagnosis supported by studies of living patients.
Of the 137 mummies, 76 were Egyptian, with the oldest from about 1800 B.C.; 51 Peruvian, from 900 B.C. to A.D. 1500; five Puebloans from the American West, from 1500 B.C. to A.D. 1500; and five Aleutian natives from the 18th, 19th and early 20th centuries.
Atherosclerosis was present in 38 percent of the Egyptians, 25 percent of the Peruvians, 40 percent of the Puebloans and 60 percent of the Alaska natives (although the number of mummies of the latter two groups is so small that the percentages are statistically meaningless).
Whether any of the mummified people died of atherosclerotic disease could not be determined.
Only the Egyptian bodies were intentionally preserved. The others were naturally mummified by the cold and dry conditions of the places where the people died. As a consequence, they may not be representative snapshots of their populations. Nevertheless, a few generalities stand out.
One of them is that atherosclerosis increases with age. Those with no sign of the condition had an average estimated age at death of 32 years. Slightly more than half the mummies in their 40s, however, had at least one calcified artery. For the few mummies older than 50, the prevalence was lower — about 40 percent.
Studies of present-day populations have found a similar increase in calcium with age as well as atherosclerosis in young adults.
A review of 3,832 autopsies done on troops who died in combat or of unintentional injuries in the Iraq and Afghanistan wars found that 9 percent had atherosclerosis in the coronaries. That’s a dramatic drop from the prevalence found in autopsies of casualties of the Korean (77 percent) and Vietnam (45 percent) wars.
The team plans to examine more remains. Next up are naturally mummified bodies from Mongolia and “bog people” preserved in peat deposits in Britain and Scandinavia.
The latter group may be hard to evaluate, however, because the bogs the bodies were thrown into (often following execution) had acidic water that dissolves calcium, including most of the bones.