The impacts of noise and air pollution on breast cancer risk in European and East Asian populations: Insights from genetic evidence.

Objectives: Previous studies have reported associations of noise and air pollution with breast cancer (BC) risk, but the causality remains unclear. This study aimed to explore the effects of noise and air pollution on BC from a genetic perspective.

Study design: Genetic association study.

Methods: We began our investigation by visualizing the development trends in this field through bibliometric analysis. Subsequently, we conducted Mendelian randomization analyses to assess the effects of noise (daytime and evening) and air pollution (NO₂, NO_x, PM_2.5, PM_2.5-10, and PM₁₀) on BC. Genetic variants extracted from genome-wide association studies (GWAS) robustly associated with noise and air pollution were used as instrumental variables. The GWAS data for BC in European and East Asian populations were obtained from the Breast Cancer Association Consortium and the Biobank Japan, respectively.

Results: The effects of noise and air pollution on BC are receiving increasing attention. In the European population, genetically predicted exposure to NO₂ (OR: 1.9381; 95% CI: 1.2873-2.9180; P = 0.0015) and PM₁₀ (OR: 1.4187; 95% CI: 1.0880-1.8500; P = 0.0098) were positively associated with overall BC risk. Subtype analyses showed that PM₁₀ was significantly related to the risks of both ER+ (OR: 1.6165; 95% CI: 1.1778-2.2186; P = 0.0030) and ER- (OR: 1.6228; 95% CI: 1.0175-2.5881; P = 0.0421) BC. Additionally, NO₂ only increased the risk of ER+ BC (OR: 1.7429; 95% CI: 1.0679-2.8444; P = 0.0262), but not ER- BC. In East Asians, genetically predicted NO₂ was positively related to BC risk (OR: 1.1394; 95% CI: 1.0082-1.2877; P = 0.0366).

Conclusions: Our study gave new evidence from a genetic standpoint underscoring that improving the environmental quality of residential areas is conducive to reducing BC risk.