Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.6.3
Radon

1.2.6.3.3
Case-Control Studies

"A nested case-control study in Finland... 1,973 lung cancer case patients (excluding patients with cancers of the pleura) diagnosed from January 1, 1986, until March 31, 1992, within a cohort of Finns residing in the same one-family house from January 1, 1967, or earlier, until the end of 1985, and 2,885 control subjects identified from the same cohort and matched by age and sex ... the odds ratio (OR) of lung cancer was estimated from matched and unmatched logistic regression analyses relative to indoor radon concentration assessed by use of a 12-month measurement with a passive alpha track detector."

"Five hundred seventeen case-control pairs were used in the matched analysis, and 1,055 case subjects and 1,544 control subjects were used in the unmatched analysis. The OR of lung cancer for indoor radon exposure obtained from matched analysis was 1.01 (95% confidence interval [CI] = 0.94-1.08) per 2.7 pCi/L (100 Bq/m³]) after adjustment for the cigarette smoking status, intensity, duration, and age at commencement of smoking by subjects. For indoor radon concentrations 1.4-2.6, 2.7-5.3, 5.4-10.7, and 10.8-34.5 pCi/L (50-99, 100-199, 200-399, and 400-1277 Bq/m³, respectively), the matched ORs were 1.03 (95% CI = 0.84-1.26), 1.00 (95% CI = 0.78-1.29), 0.91 (95% CI = 0.61-1.35), and 1.15 (95% CI = 0.69-1.93), respectively, relative to the concentration below 1.4 pCi/L (0-49 Bq/m³). The unmatched analysis yielded similar results with somewhat smaller CIs. In the analyses stratified by age, sex, smoking status, or histologic type of lung cancer, no statistically significant indications of increased risk of lung cancer related to indoor radon concentration were observed for any of the subgroups.

"Conclusions: Our results do not indicate increased risk of lung cancer from indoor radon exposure.

"Implication: Indoor radon exposure does not appear to be an important cause of lung cancer."