Low-dose radiation can cause heart disease and stroke too

A new study by researchers at Imperial College London suggests that exposure to low-dose radiation may raise risk of cardiovascular events such as heart attacks and stroke.

The researchers constructed a mathematical model based on which they predicted that higher doses of radiation lead to higher risk of cardiovascular disease. The observation is consistent with previous studies of nuclear workers.

The results were published Oct 23, 2009 in the open access journal PLoS Computational Biology.

Cardiovascular disease is the leading cause of death and disability in developed countries. Exposure to high doses of radiation has been known to be associated with higher risk of cancer. But few people know that actually radiation can also damage arteries causing cardiovascular disease.

In fact, high-dose radiotherapy has been known to cause inflammation in the heart and large arteries. But the risk associated with exposure to low doses of radiation has been downplayed.

Dr. Mark Little and colleagues studied a novel mechanism that suggests that radiation kills monocytes, a type of white blood cell in the arterial wall, which would otherwise be able to bind to monocyte chemo-attractant protein 1, according to a press release by Public Library of Science.

The mechanism if proved to be valid would imply that risks from low dose radiation from medical and dental x-rays may have been substantially underestimated, the authors said.

Radiation, to be exact in this case, x-ray, is recognized by the U.S. National Toxicology Program as a carcinogen. Late nuclear physician and physicist John Gofman, Ph.D. M.D. said that there is no safety threshold and exposure to any dose of radiation causes certain damage. And the damage is cumulative.

By David Liu