RESIDENTIAL RADON EXPOSURE AND LUNG-CANCER - AN EPIDEMIOLOGIC-STUDY OF NORWEGIAN MUNICIPALITIES

The study is based on a collaboration between the cancer Registry of N orway, the Norwegian Radiation Protection Authority, and National Radi ological Protection Board (NRPB, UK). The association between indoor r adon exposure and lung cancer was studied in 427 municipalities. NRPB detectors were sent to 10,000 householders, and 7,500 of the detectors were returned. Data from a nation-wide survey of smoking habits in 19 64-1965 were available. Data on asbestos exposure were also used in a regression analysis. The reporting to the Cancer Registry of all new c ases of cancer is fairly complete, as hospital departments and institu tes of pathology are obliged to report all cancer cases. The histologi cally confirmed lung cancer cases were grouped into squamous-cell carc inoma, small-cell carcinoma, adenocarcinoma and other or non-specified histological types. The age-adjusted rate of lung cancer by histologi cal type was the dependent variable in the regression analysis. A cons istent increase in incidence of lung cancer was seen with increasing t obacco consumption, but no positive trend could be shown with increasi ng radon exposure in the descriptive presentation of the data. In the regression analysis, however, the incidence of small-cell anaplastic l ung tumors in females increased significantly with increasing radon ex posure. When based on the regression coefficients, the fraction of lun g cancers attributable to radon is about 2-4%. However, systematic err ors cannot be excluded in an ecological study such as presented here. (C) 1994 Wiley-Liss, Inc.