Radon and thyroid cancer risk in the Women’s Health Initiative
Menée à l'aide de données portant sur 158 770 Américaines ménopausées (durée moyenne de suivi : 17,7 ans), cette étude analyse l'association entre une exposition résidentielle au radon et le risque de cancer de la thyroïde après 50 ans (521 cas)
Background: Exposure to ionizing radiation during youth is an established risk factor for thyroid cancer but whether exposure during adulthood increases risk is unclear. The major source of ionizing radiation for most individuals is radon gas at home. We examined the association between residential radon exposure and incident thyroid cancer among middle-aged and older women in the United States.
Methods: We leveraged data from a prospective cohort study of postmenopausal women from the Women’s Health Initiative and household radon concentrations from the 1993 US Geological Survey, measured in picocuries per liter (pCi/L). We used Cox proportional hazards to estimate the risk of incident thyroid cancer during follow-up through 2024 as a hazard ratio and 95% confidence intervals (CIs), adjusting for study design and participant demographic, social, behavioral, and clinical characteristics.
Results: Among 158,770 women without thyroid cancer at baseline, 521 incident thyroid cancers were observed over a mean follow-up of 17.7 years. Incidence rates were 18.5, 18.2, and 19.5 cancers per 100,000 woman-years at radon concentrations of < 2, 2–4, and > 4 pCi/L, respectively. After adjustment for covariates, women living at concentrations of 2–4 and > 4 pCi/L did not have higher hazards of thyroid cancer compared to women living at < 2 pCi/L: hazard ratios were (95% CI) 0.99 (0.80–1.23) and 0.92 (0.70–1.21). Similar results were obtained in sensitivity analyses using alternative approaches to radon measurements.
Conclusions: Although exposure misclassification could have influenced these findings, residential radon exposure during adulthood does not appear to be associated with risk of incident thyroid cancer among postmenopausal women.
BMC Cancer , article en libre accès, 2026