British study links radiation to heart disease

LONDON (Reuters) - Nuclear power plant workers exposed to chronic radiation may face a higher risk of heart disease, according to a large British 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 plc and the Nuclear Decommissioning Authority -- were also typically 5 to 10 times lower than radiation experienced by atomic bomb survivors, the researchers said.

Dudley Goodhead, a radiation expert at Britain's Medical Research Council, who was not involved in the study, said studies of atomic bomb survivors in Japan had suggested a link with heart disease too.

"The findings of the present study clearly suggest that even chronic exposure to radiation, spread over long periods of time such as received by some radiation workers in the past, may also be able to cause increased heart disease," he said.

(Reporting by Michael Kahn; editing by Jon Boyle)