Study links radiation to heart disease

By Michael Kahn

LONDON (Reuters) - Nuclear power plant workers exposed to chronic radiation may face a higher risk of heart disease, according to a large study published on Tuesday.

Other research has shown that high exposure over a short period of time may cause heart disease but the new findings link exposure to long-term exposure at relatively lower levels, the researchers said in the International Journal of Epidemiology.

"Our results provide more evidence of a link," said Steve Jones, a researcher at Westlakes Scientific Consulting, who led the study. "This adds to the evidence of similar associations from other studies.

The researchers cautioned that further studies were needed to consider factors such as diet, exercise, cholesterol levels and smoking habits that affect the risk of heart disease.

The study focused on more than 65,000 workers employed between 1946 and 2002 at four sites operated by British Nuclear Fuels plc and its predecessors. The team analyzed non-cancer death rates and cumulative radiation exposure using the workers' personal dosimeter badges.

Comparing the some 42,000 workers exposed to relatively high levels of radiation to office workers and other employees pointed to an increased heart disease risk, the researchers said.

The effect on life expectancy was slight -- about a year at most -- while the risk was greatest for people who worked before the 1980s when safety conditions improved, the researchers said. The risk rose with the level of radiation exposure.

The top doses in the study -- funded by British Nuclear Fuels and the Nuclear Decommissioning Authority -- were also typically 5 to 10 times lower than radiation experienced by atomic bomb survivors, the researchers said.