Atherosclerosis, or the narrowing of arteries due to build up of fatty deposits, is thought to be a modern disease but an examination of mummies of five ancient cultures by the Horus mummy research team has found that the disease was present long before the evolution of modern lifestyles, with the researchers suggesting potential causes that could have led to the formation of the disease in a report that has been published in the journal Global Heart.
Among the five cultures, the 76 ancient Egyptians studied were wealthy enough to undergo the 70-day mummification process, and might have been expected to have a lifestyle conducive to atherosclerosis. The Egyptians studied were predominately members of the Pharaoh's court and may not have been as active or had as healthy a diet as the common man. However, the four other cultures had no such expensive mummification processes. The dead were left to dry out on their own, either in a desert or a fiercely cold environment. Their abdominal organs were left inside the body and expensive oils, resins and drying measures were not employed. These mummies were common men and women of their time. The 51 Peruvians of 600 to 2,000 years ago were prehistoric, as were the five Native Americans of Utah and Colorado of approximately 1,600 years ago. Neither culture had a written language. The small group of Mongolians studied from 500 years ago lived a primitive nomadic lifestyle in the Gobi Desert. The five Aleutian Islanders of 150 years ago obtained their food from the Bering Sea and its shoreline, hunting and gathering for food without benefit of agriculture or domestic animals. Yet the Hours team found that these people of ancient lifestyles were also plagued by atherosclerosis.
None of these cultures suffered from significant obesity, lack of physical activity, cigarette smoking, or other well-known 'modern' risk factors that can cause narrowing of the arteries and thus raise the risk of heart attack, stroke, and other cardiovascular problems. However, the authors suggest that a non-traditional cause or causes of atherosclerosis could explain the burden of atherosclerosis in ancient peoples. Thomas comments, "These ancient people were unaware of the germs lurking in the unhygienic environments in which they lived, animals and people living side by side, inadequate sewage, contaminated water. They did not know that the germs amongst which they lived caused infection after infection. In addition to frequent bacterial and viral infections, the ancients likely suffered from lifelong parasitic infestations. Modern medicine, knowledge and antibiotics had not yet arrived."
A strong and prolonged inflammatory effort by the body would have been necessary to fight off the infections that plagued ancient humans. However, this intense inflammatory response may have accelerated the inflammation that occurs when cholesterol, an unwelcome guest, gets into the wall of the artery. Inflammation is an integral part of the atherosclerotic process. Cholesterol is not supposed to be in the wall, thus the body fights it. The process is counterproductive, however, attracting more unwelcome cells in the wall of the artery resulting in a further build up of an atherosclerotic plaque.
As evidence, the authors cite a 1974 investigation into the mummy 'Nakht', a teenage boy who worked as a weaver circa 1200 BCE in Thebes (modern day Luxor, Egypt). The extensive investigation found that Nakht was infected with four parasites, suffering from schistosomiasis, trichinosis, malaria and tapeworm infestation. The authors comment: "If Nakht is representative of those living along the ancient Nile, these populations must have endured enormous, lifelong inflammatory burdens." Other mummies were found to be harbouring tuberculosis infections.
There is precedence of inflammation accelerating atherosclerosis in the modern day. People with conditions of ongoing inflammation, those with rheumatoid arthritis, systemic lupus erythematosus or human immunodeficiency virus infection, experience premature and aggressive atherosclerosis leading to early heart disease and death. Thomas and colleagues suggest the inflammatory process, necessary to fight off infection in ancient times in particular, could backfire by promoting atherosclerosis in the absence of modern risk factors.
Tobacco was not available to any of these ancient cultures, but could smoking represent another cause for this unexpected atherosclerosis? Modern appliances were unavailable, and cooking was performed over a fire. The same fire could be used to ward off insects and for light and warmth. Dr Thomas comments, "We noticed a trend toward more women than men developing atherosclerosis in ancient times. The traditional role of women in these times, cooking over a fire for much of the day, could have represented the scourge of smoking of the time. Inhalation of smoke day-in and day-out could have initiated and propelled the atherosclerotic process."
Thomas and Narula comment that the bulk of our modern risk factors were discovered several generations ago, before genetic testing and modern biomarker analysis. "Each year we learn more and more about the impact of the human genome and molecules in our blood, and so to believe we have already uncovered all the causes, or risk factors, of atherosclerosis may be wishful thinking. Using the past to predict the future, as these ancient people unexpectedly had atherosclerosis, we need to continue to search for other potential fundamental causes of atherosclerosis. The discovery of new causes could dramatically reshape the frequency and impact of atherosclerosis today."
They add: "There is a surprising similarity in the amount and distribution of atherosclerotic calcifications between ancient Egyptians and current Americans of a similar age. This is observed, even though many of what we believe to be major risk factors must be different between the two populations. There was no tobacco in ancient Egypt. Ancient Egyptians must have been more active than current Americans, and some of the dietary issues that exist in the USA today did not exist in ancient Egypt. This should lead to re-evaluation of the root causes of atherosclerosis, and may lead to entirely new avenues of prevention and early treatment."