Exposure to outdoor ambient air toxics and risk of breast cancer: The multiethnic cohort

Julia E Heck; Di He; Sam E Wing; Beate Ritz; Chandra D Carey; Juan Yang; Daniel O Stram; Loïc Le Marchand; Sungshim Lani Park; Iona Cheng; Anna H Wu

doi:10.1016/j.ijheh.2024.114362

Exposure to outdoor ambient air toxics and risk of breast cancer: The multiethnic cohort

Int J Hyg Environ Health. 2024 Apr 3:259:114362. doi: 10.1016/j.ijheh.2024.114362. Online ahead of print.

Authors

Julia E Heck¹, Di He², Sam E Wing², Beate Ritz², Chandra D Carey³, Juan Yang⁴, Daniel O Stram⁵, Loïc Le Marchand⁶, Sungshim Lani Park⁶, Iona Cheng⁷, Anna H Wu⁵

Affiliations

¹ Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA; College of Health and Public Service, University of North Texas, Denton, TX, USA; Center for Racial and Ethnic Equity in Health and Society, University of North Texas, Denton, TX, USA. Electronic address: julia.heck@unt.edu.
² Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA, USA.
³ College of Health and Public Service, University of North Texas, Denton, TX, USA; Center for Racial and Ethnic Equity in Health and Society, University of North Texas, Denton, TX, USA.
⁴ Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
⁵ Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
⁶ Epidemiology Section, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, Honolulu, HI, USA.
⁷ Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA; University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA.

PMID: 38574449
DOI: 10.1016/j.ijheh.2024.114362

Abstract

Background: A growing literature has reported associations between traffic-related air pollution and breast cancer, however there are fewer investigations into specific ambient agents and any putative risk of breast cancer development, particularly studies occurring in populations residing in higher pollution areas such as Los Angeles.

Objectives: To estimate breast cancer risks related to ambient air toxics exposure at residential addresses.

Methods: We examined the relationships between ambient air toxics and breast cancer risk in the Multiethnic Cohort among 48,665 California female participants followed for cancer from 2003 through 2013. We obtained exposure data on chemicals acting as endocrine disruptors or mammary gland carcinogens from the National-Scale Air Toxics Assessment. Cox proportional hazards models were used to estimate breast cancer risk per one interquartile range (IQR) increase in air toxics exposure lagged by 5-years. Stratified analyses were conducted by race, ethnicity, and hormone receptor types.

Results: Among all women, increased risks of invasive breast cancer were observed with toxicants related to industries [1,1,2,2-tetrachloroethane (hazard ratio [HR] = 4.22, 95% confidence interval [95% CI] 3.18-5.60), ethylene dichloride (HR = 2.81, 95% CI 2.20-3.59), and vinyl chloride (HR = 2.27, 95% CI 1.81, 2.85); these 3 agents were correlated (r2 = 0.45-0.77)]. Agents related to gasoline production or combustion were related to increased breast cancer risk [benzene (HR = 1.32, 95% CI 1.24, 1.41), ethylbenzene (HR = 1.20, 95% CI 1.13-1.28), toluene (HR = 1.29, 95% CI 1.20-1.38), naphthalene (HR = 1.11, 95% CI 1.02-2.22), acrolein (HR = 2.26, 95% CI 1.92, 2.65)]. Higher hazard ratios were observed in African Americans and Whites compared to other racial and ethnic groups (p-heterogeneity <0.05 for traffic-related air toxics, acrolein, and vinyl acetate).

Conclusions: Our findings suggest that specific toxic air pollutants may be associated with increase breast cancer risk.

Keywords: 1,1,2,2-tetrachloroethane; Acrolein; Benzene; Breast cancer; Ethylbenzene; Ethylene dichloride; Naphthalene; Toluene; Vinyl chloride.