TitleGeographic variation in radon and associated lung cancer risk in Canada.
Publication TypeJournal Article
Year of Publication2014
AuthorsHystad, P, Brauer, M, Demers, PA, Johnson, KC, Setton, E, Cervantes-Larios, A, Poplawski, K, McFarlane, A, Whitehead, A, Nicol, A-M
JournalCan J Public Health
Date Published01/2014
KeywordsAged, Canada, Case-Control Studies, Environmental Exposure, Female, Humans, Logistic Models, Lung Neoplasms, Male, Middle Aged, Radon, Residence Characteristics, Risk Factors

OBJECTIVE: Radon is an important risk factor for lung cancer. Here we use maps of the geographic variation in radon to estimate the lung cancer risk associated with living in high radon areas of Canada.

METHODS: Geographic variation in radon was estimated using two mapping methods. The first used a Health Canada survey of 14,000 residential radon measurements aggregated to health regions, and the second, radon risk areas previously estimated from geology, sediment geochemistry and aerial gamma-ray spectrometry. Lung cancer risk associated with living in these radon areas was examined using a population-based case-control study of 2,390 lung cancer cases and 3,507 controls collected from 1994-1997 in eight Canadian provinces. Residential histories over a 20-year period were used in combination with the two mapping methods to estimate ecological radon exposures. Hierarchical logistic regression analyses were used to estimate odds ratios for lung cancer incidence, after adjusting for a comprehensive set of individual and geographic covariates.

RESULTS: Across health regions in Canada, significant variation in average residential radon concentrations (range: 16-386 Bq/m3) and in high geological-based radon areas (range: 0-100%) is present. In multivariate models, a 50 Bq/m3 increase in average health region radon was associated with a 7% (95% CI: -6-21%) increase in the odds of lung cancer. For every 10 years that individuals lived in high radon geological areas, the odds of lung cancer increased by 11% (95% CI: 1-23%).

CONCLUSIONS: These findings provide further evidence that radon is an important risk factor for lung cancer and that risks are unevenly distributed across Canada.

Alternate JournalCan J Public Health
PubMed ID24735695
PubMed Central IDPMC6972071