Air pollution Exposure And Mammographic Breast Density In Tehran, Iran

Abstract

Background: Air pollution is one of the major public health challenges in many parts of the world possibly has an association with breast cancer. However, the mechanism is still unclear. This study aimed to find an association between exposure to six criteria ambient air pollutants (PM2.5, PM10, SO2, NO2, O3, and CO) and mammographic breast density (MBD), as one of the strongest predictors for developing breast cancer, in women living in Tehran, Iran.Methods: Participants were selected from women attending two university hospitals for screening mammography from 2019 to2021. Breast density was rated by two expert radiologists. Individual exposures to 3-years ambient air pollution levels at the residence were estimated.Results: The final analysis in 791 eligible women showed that low and high breast density was detected in 34.8% and 62.2% of participants, respectively. Logistic regression analysis after considering all possible confounding factors represented that an increase in 10 units of NO2 (ppb) exposure was associated with an increased risk of breast density with an OR equal to 1.47 (95% CI: 1.10 to 1.97). Furthermore, CO level was associated with a decreasing breast density (OR = 0.33, 95% CI = 0.17 to 0.64). None of the other pollutants were associated with breast density.Conclusion: MBD was associated with higher levels of ambient air NO2 and lower levels of CO. Perhaps MBD monitoring as an available tool in each population, can help the prediction of future breast cancer occurrence and finding the high-risk geographic areas.