News in Science

Heart disease a 4000-year-old 'serial killer'

Ancient arteries The diseased arteries of ancient mummies are challenging modern assumptions about the causes of cardiovascular disease.

Whole-body CT scans of 137 mummies from different countries, cultures and lifestyles spanning 4000 years of history has found evidence of hardened arteries in at least one-third of the mummies.

The international study, published today in the Lancet, calls into question the assumption that cardiovascular disease is a uniquely modern disease resulting from poor diet and lifestyle choices.

"I'd say we've shown heart disease is a serial killer that's stalked mankind for 4000 years," says lead author Dr Randall C. Thompson, attending cardiologist at Saint Luke's Mid America Heart Institute in Kansas City.

The mummies included individuals from ancient Egypt, ancient Peru, the Ancestral Puebloans of the southwest America, and the Unangan of Alaska's Aleutian Islands.

Critically for the study the Unangan people lived a traditional hunter-gatherer lifestyle.

"Some people believe that a hunter-gatherer lifestyle should be more natural for our genetic machinery than the artificial food and inactivity that we have," says Thompson.

"[But] three out of the five of the Aleutian mummies had these calcifications, the sediment that forms in the arteries when the disease happens."

Earlier evidence

This study follows from earlier research that found clear evidence of atherosclerosis - a condition where arteries are hardened and narrowed by calcified deposits of fat, cholesterol and other substances - in a large number of mummies from ancient Egypt.

"That study was critiqued that perhaps we had simply found a modern disease in people that had a modern-type lifestyle, who ate a rich diet and didn't get very much exercise and so forth," he says.

"That's possible because the Ancient Egyptians that were mummified tended to be the wealthier people and some of them were quite well cared for and ate a rich diet."

However the new findings show that atherosclerosis defies cultural, geographic and lifestyle classifications as the diets of these peoples were quite disparate, as were the climates.

The researchers do point out a number of key common factors across the disparate cultures that might also have played in the onset of artherosclerosis.

"Common to all populations was the use of fire for cooking and warmth," the authors say, adding that this suggests smoke inhalation may have played a role in the development of artherosclerosis.

To support this view they point to earlier autopsies of Unangan and Inuit mummies that had shown extensive pulmonary anthracosis, which is a lung disease common to coalminers.

The study also highlights the high level of chronic infection and inflammation present in premodern civilisations may have also contributed to the inflammatory aspects of artherosclerosis.

"These findings suggest that our understanding of the causative factors of atherosclerosis is incomplete, and that atherosclerosis could be inherent to the process of human ageing," the authors conclude.

Studying ancient remains can have significant implications for modern assumptions about the causes of cardiovascular and other diseases, says forensic archaeologist Dr Estelle Lazer, who was not involved with the study.

"Looking at the past can be quite useful for understanding our species and modern illnesses - it's got a value for epidemiology," says Lazer, honorary research associate at the University of Sydney.

While there have been numerous previous studies focusing on individual mummies, Dr Lazer says this study has the advantage of numbers, even if two of the populations examined were only represented by small numbers of mummies.

"When you start to look at large numbers of them, you start to be able to say things that are much more interesting," says Lazer.

"It looks very much like [atherosclerosis] is age-related and of course a lot more of us are living a lot longer so more of us are falling prey to these disorders."