Indoor radon and lung cancer in France.
BACKGROUND
Several case-control studies have indicated an increased risk of lung cancer linked to indoor radon exposure; others have not supported this hypothesis, partly because of a lack of statistical power. As part of a large European project, a hospital-based case-control study was carried out in 4 areas in France with relatively high radon levels.


METHODS
Radon concentrations were measured in dwellings that had been occupied by the study subjects during the 5- to 30-year period before the interview. Measurements of radon concentrations were performed during a 6-month period using 2 Kodalpha LR 115 detectors (Dosirad, France), 1 in the living room and 1 in the bedroom. We examined lung cancer risk in relation to indoor radon exposure after adjustment for age, sex, region, cigarette smoking, and occupational exposure.


RESULTS
We included in the analysis 486 cases and 984 controls with radon measures in at least 1 dwelling. When lung cancer risk was examined in relation to the time-weighted average radon concentration during the 5- to 30-year period, the estimated relative risks (with 95% confidence intervals) were: 0.85 (0.59-1.22), 1.19 (0.81-1.77), 1.04 (0.64-1.67), and 1.11 (0.59-2.09) for categories 50-100, 100-200, 200-400, and 400+ becquerels per cubic meter (Bq/m), respectively (reference <50 Bq/m). The estimated relative risk per 100 Bq/m was 1.04 (0.99-1.11) for all subjects and 1.07 (1.00-1.14) for subjects with complete measurements.


CONCLUSIONS
Our results support the presence of a small excess lung cancer risk associated with indoor radon exposure after precise adjustment on smoking. They are in agreement with results from some other indoor radon case-control studies and with extrapolations from studies of underground miners.
Institut de Radioprotection et de Sûreté Nucléaire, Direction de la Radioprotection de l'Homme, Service de Radiobiologie et d'Epidémiologie, 92262 Fontenay-aux-Roses, France. helene.baysson@irsn.fr
Hélène
H
Baysson
Margot
M
Tirmarche
Georges
G
Tymen
Sylvie
S
Gouva
Denis
D
Caillaud
Jean-Claude
JC
Artus
Alain
A
Vergnenegre
Françoise
F
Ducloy
Dominique
D
Laurier
D000368:Aged; D000396:Air Pollutants, Radioactive / Q000032:analysis; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D016001:Confidence Intervals; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011886:Radon / Q000032:analysis*; D012307:Risk Factors; D012907:Smoking; D013997:Time Factors
D000396:Air Pollutants, Radioactive; D011886:Radon