Mortality and cancer risks for radiation workers

The risk of developing cancer among radiation workers increases with the dose of ionising radiation they are exposed to, according to a study by the Health Protection Agency published today in the British Journal of Cancer. The observed cancer risks are consistent with the international scientific consensus on radiation protection.

The study also shows that overall mortality in the UK's 175,000 radiation workers is lower than that in the general population. This "healthy worker effect" has been observed in studies of many other occupational groups.

Dr Colin Muirhead from the Health Protection Agency said: "This is a continuation of a study started in 1976 and it provides reliable information on the health of people working with ionising radiation. The results confirm the cancer risk estimates observed in other studies even though, overall, radiation workers have lower cancer risks than the general population."

This study provides the most precise estimates to date of mortality and cancer risks following occupational radiation exposure and strengthens the scientific evidence for raised risks from these exposures. The cancer risk estimates are consistent with international radiation protection standards, both for leukaemia and for all other cancers combined.

Continued follow-up of these workers will be valuable in determining whether radiation-associated risks vary over time or by age, and enables the study of specific cancers and causes of death in more detail. The research will also make a useful contribution to wider national and international studies on the effects of occupational exposures to ionising radiation.

In a separate paper published at the same time, researchers at the Childhood Cancer Research Group at the University of Oxford and the Health Protection Agency have studied cancer in the children of female radiation workers. This study does not support an earlier finding of a raised risk of cancer. In a subgroup of women who worked with radiation during pregnancy, a weak statistical association was found between maternal radiation work and childhood cancer, but the evidence is limited by the small numbers involved and the result may be due to chance.

The two papers are published in the British Journal of Cancer and radiation workers and their representatives were informed of the results before publication.

(Source: Cancer Research UK: British Journal of Cancer: February 2009)