Global trends and projections of lung cancer attributable to residential radon exposure, 1990–2050

Radon exposure is one of the major environmental risk factors for lung cancer and a key cause of death worldwide. Although its health effects are becoming increasingly recognized, there are a few comprehensive assessments of the burden of lung cancer caused by residential radon across diverse regions and demographics. This study used machine learning-based SHapley Additive exPlanations (SHAP) analysis to elucidate the spatiotemporal trends of lung cancer attributed to global, regional, and national residential radon exposure from 1990 to 2021, project future trajectories through 2050, and quantify the key drivers of burden heterogeneity. Disability-adjusted life years (DALYs) and age-standardized mortality rates (ASMRs) were calculated using data from the Global Burden of Disease Study 2021. Temporal trends and average annual percent changes (AAPC) were determined using joinpoint regression. The Age-Period-Cohort (APC) and Bayesian Age-Period-Cohort (BAPC) models were used to assess age-specific risks and project future trends through 2050. Spatial heterogeneity was analyzed across 204 countries and territories. Additionally, the contributions of demographic, geographic, and health system factors to mortality from radon exposure-attributable lung cancer were measured using SHAP analysis. From 1990 to 2021, lung cancer deaths worldwide attributable to residential radon increased from 49,236 to 82,160. However, the ASMR decreased by 23.78% (95% UI: − 31.98 to − 15.10), from 1.26 to 0.96 per 100,000, which corresponded to an AAPC of − 0.88% (95% UI: − 1.03 to − 0.74). This decline was primarily attributed to male sex (AAPC: − 1.24%, 95% CI: − 1.40 to − 1.08), whereas the ASMR among women remained relatively stable (AAPC: − 0.07%, 95% UI: − 0.24 to 0.09). Although DALYs increased by 5.51% in low-middle Socio-demographic Index (SDI) regions, they decreased by 31.00% in high-middle SDI regions. Eastern Europe and Central Asia reported the highest ASMR, whereas Africa reported the lowest. According to BAPC projections, ASMR will continue to decrease globally until 2050, particularly among men. However, DALYs may increase among women. SHAP analysis suggested that age 70 to 79 (0.375), Sex_Male (0.235), and Geological_radon (0.221) were the major drivers of radon exposure-attributable lung cancer mortality. The country-level analysis showed bidirectional impacts of healthcare access. Despite worldwide decreases in the radon exposure-related lung cancer burden, marked disparities still exist across sexes, age groups, and SDI regions. SHAP analysis identifies advanced age, male sex, and geological radon potential as the primary drivers of burden heterogeneity. Despite established stable mortality trends, the growing burden in low-resource settings and the projected rise in DALYs among women necessitate targeted interventions, including radon mitigation policies, increased surveillance, and public awareness campaigns. To lessen the future burden of radon-associated lung cancer, older adults, high-risk regions, and sex-specific prevention strategies should be prioritized.