Background: Radon, a naturally occurring radioactive gas, is a carcinogen that causes a small proportion of lung cancers among exposed populations. Theoretical models suggest that radon may also be a risk factor for skin cancer, but epidemiologic evidence for this relationship is weak. In this study, we investigated ecologic associations between environmental radon concentration and the incidence of various types of skin cancer.
Methods: We analyzed data for 287 small areas (postcode sectors) in southwest England for the years 2000–2004. Poisson regression was used to compare registration rates of malignant melanoma, basal cell carcinoma, and squamous cell carcinoma across mean indoor radon concentrations from household surveys. Analyses were adjusted for potentially confounding factors, including age, sex, population socioeconomic status, and mean hours of bright sunshine.
Results: No association was observed between mean postcode sector radon concentration and either malignant melanoma or basal cell carcinoma registration rates. However, sectors with higher radon levels had higher squamous cell carcinoma registration rates, with evidence of an exposure-response relationship. Comparing highest and lowest radon categories, postcode sectors with mean radon ≥230 Bq/m3 had registration rates 1.76 (95% confidence interval=1.46–2.11) times those with mean radon 0–39 Bq/m3. Associations persisted after adjustment for potential confounders.
Conclusions: This ecologic study suggests that environmental radon exposure may be a risk factor for squamous cell carcinoma. Further study is warranted to overcome ecologic design limitations and to determine whether this relationship is generalizable to national and international settings.
From the European Centre for Environment & Human Health, Peninsula College of Medicine & Dentistry, University of Exeter, Knowledge Spa, Royal Cornwall Hospital, Truro, United Kingdom.
Submitted 27 May 2011; accepted 2 September 2011; posted 11 November 2011.
The European Centre for Environment and Human Health (part of the Peninsula College of Medicine and Dentistry, which is a joint entity of the University of Exeter, the University of Plymouth and the NHS in the South West) is supported by investment from the European Regional Development Fund and the European Social Fund Convergence Programme for Cornwall and the Isles of Scilly. The authors reported no other financial interests related to this research.
Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com).
Correspondence: Benedict W. Wheeler, European Centre for Environment & Human Health, Peninsula College of Medicine & Dentistry, University of Exeter, Knowledge Spa, Royal Cornwall Hospital, Truro, TR1 3HD, United Kingdom. E-mail: email@example.com.