An ecological study of cancer incidence and radon levels in South West England.

To investigate the relationship of domestic radon levels and cancer, the incidence of 14 major cancers in Devon and Cornwall were examined in relation to the local radon levels. Cancer registrations for 1989-1992 were provided by the South-Western Regional Cancer Registry. The average radon levels for postcode sectors were sorted into ten categories from low (< 40 Bq/m3) to extremely high (> or = 230 Bq/m3) and age-standardised incidence rates were calculated for each radon category. The incidence rates for lung cancer, where radon has been claimed to be a risk factor, were very similar across all domestic radon categories. Only non-melanoma skin cancers, showed a significant increase in incidence in the high-radon postcode sectors (> or = 100 Bq/m3) compared with the low-radon sectors (< 60 Bq/m3) and this effect was observed for both sexes. The remaining 12 cancer sites showed no significant trend in incidence rates with increasing radon concentration. There was no significant difference in corrected survival rates for any cancer site between the low- and high-radon areas. The possible contribution of confounding factors to the results of this study is discussed.