A prospective cohort analysis of residential radon exposure and malignant melanoma mortality in the Swiss population

Abstract

BACKGROUND AND AIM: Radon is radioactive noble gas naturally found in earth crust and tend to accumulate in buildings. Studies suggest alpha particles emitted by radon can induce carcinogenic effect and long-term exposure to residential radon can contribute the risk of developing malignant melanoma. The purpose of this study was to investigate the association between residential radon and malignant melanoma mortality. METHODS: 4.9 million adults were included from the Swiss National Cohort. Cox proportional hazard models were used to estimate hazard ratios (20+ years old; follow-up 2001-2016). Long-term modeled radon and average ambient ultra-violet exposures were assigned at baseline, and included in multi-pollutant models. With age as a time scale, the models were adjusted for calendar time, sex, marital status, education level, mother tongue, socioeconomic position, and outdoor occupation from job-exposure-matrix. Effect modification of adjusted variables on both exposures were investigated. RESULTS:During ~13.6 years of follow-up, 3,979 malignant melanoma deaths as primary cause and 4,585 deaths including consecutive, concomitant, and initial diseases were observed. The adjusted hazard ratios per 100 Bq/m³ increase in residential radon at age 60 were 1.10 (95% CI: 0.99, 1.23) and 1.13 (95% CI: 1.02, 1.25) for primary cause and all causes, respectively. Association between residential radon and primary deaths from malignant melanoma modified by employment status at baseline and were stronger among females but the effect modification of sex was not statistically significant. CONCLUSIONS:Residential radon exposure might contribute to mortality from malignant melanoma while accounting for important confounders. Accumulation of radon indoors is preventable and has public health importance. KEYWORDS: Ionizing radiation, mortality, environmental epidemiology