Exposure to industrial air toxics and risk of breast cancer in California-Exposure to industrial air toxics and risk of breast cancer in California

Exposure to industrial air toxics and risk of breast cancer in California

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This study examined whether living near industrial air pollution sources in California was linked to breast cancer risk. Researchers used data from 53,313 women in the California Multiethnic Cohort, followed from 1993 to 2013, and linked geocoded residential histories to EPA Toxic Release Inventory emissions from 15 industrial chemicals. Exposure was estimated with a 3 km quadratic decay model and a 5-year lag, then analyzed with Cox proportional hazards models adjusting for many breast cancer risk factors.<br /><br />The main finding was that several pollutants were associated with higher breast cancer risk: dichloromethane, tetrachloroethylene, 1,1,1-trichloroethane, diethanolamine, lead, and methyl ethyl ketone. Formaldehyde showed a notable association only with hormone receptor–negative breast cancer, suggesting the effects may differ by tumor subtype. Some results varied across racial and ethnic groups, but the authors cautioned that these differences may reflect chance or exposure patterns rather than true biological differences.<br /><br />The study’s strengths include its prospective design, large and ethnically diverse sample, detailed residential histories, and adjustment for many confounders. Limitations include possible exposure misclassification because TRI data do not capture all emissions or indoor/other sources, and distance-based modeling cannot fully account for wind, terrain, or barriers. The 5-year lag may also miss important life-stage windows of susceptibility.<br /><br />Overall, the authors conclude that residential exposure to certain industrial air toxics may increase breast cancer risk and that some pollutants may be especially relevant for specific breast cancer subtypes.

Keywords

breast cancer

industrial air pollution

California

Toxic Release Inventory

air toxics

dichloromethane

tetrachloroethylene

formaldehyde

Cox proportional hazards

residential exposure