Study of Atomic Bomb Survivors Finds Increased Risk of Stroke and Heart Disease

A dose of 0.5 Gy or higher is associated with a significantly elevated risk of stroke and heart disease, according to a Jan. 15, 2010, article in the online British Medical Journal at www.bmj.com.

Stroke and heart disease combined accounted for about a third as many radiation-associated deaths than cancer among the Japanese survivors included in the 86,611 Life Span Study cohort, according to Yukiko Shimizu, et al.

About 9,600 participants died of stroke or heart disease between 1950 and 2003, the researchers found. They estimated that the excess relative risk per gray for stroke was 9 percent, based on a linear dose-response model, except at lower doses than 0.5 Gy. Heart disease was associated with a relative risk per gray of 14 percent, with an excess risk even at lower doses.

“Prospective data on smoking, alcohol intake, education, occupation, obesity and diabetes had almost no impact on the radiation risk estimates for either stroke or heart disease, and misdiagnosis of cancers as circulatory diseases could not account for the associations seen,” the authors concluded.