A multinational study across 15 nations and covering 407, 391 workers has found significantly higher risks of developing cancer among nuclear workers.

With a total follow-up of 5.2 million person years, estimates of excess relative risks per sievert (Sv) of radiation dose for mortality from cancers other than leukaemia and from leukaemia excluding chronic lymphocytic leukaemia were assessed in the study.

The objective of the study, published in the respected British Medical Journal, is to provide direct estimates of risk of cancer after protracted low doses of ionising radiation.

The excess relative risk for cancers other than leukaemia was 0.97 per Sv while the excess relative risk for leukaemia excluding chronic lymphocytic leukaemia was 1.93 per Sv. On the basis of these estimates, the report finds that 1 – 2% of deaths from cancer among workers may be attributable to radiation.

These estimates, from the largest study of nuclear workers ever conducted, are higher than, but statistically compatible with, the risk estimates used for current radiation protection standards. The results suggest that there is a small excess risk of cancer, even at the low doses and dose rates typically received by the nuclear workers in this study.