Residential Exposure to Estrogen Disrupting Hazardous Air Pollutants and Breast Cancer Risk

Abstract

Background Some studies show increased breast cancer risk from exposure to xenoestrogens, but few have explored exposures via ambient air, which could impact large populations. Objectives This study explored the association between breast cancer risk and residential exposures to ambient estrogen disruptors among participants in a large cohort study, the California Teachers Study. Methods Participants consisted of 112,379 women free of breast cancer and living at a California address in 1995/1996. Eleven hazardous air pollutants (HAPs) from the U.S. EPA 2002 list were identified as estrogen disruptors based on published endocrine disrupting chemical lists and literature review. Census-tract estrogen disruptor concentrations modeled by the U.S. EPA in 2002 were assigned to participants’ baseline addresses. Cox proportional hazards models were used to estimate hazard ratios associated with exposure to each estrogen disruptor and a summary measure of nine estrogenic HAPs among all participants and selected subgroups, adjusting for age, race/birthplace, socioeconomic status, and known breast cancer risk factors. Results 5,361 invasive breast cancer cases were identified between 1995 and 2010. No associations were found between residential exposure to ambient estrogen disruptors and overall breast cancer risk or hormone-responsive-positive breast cancer risk, nor among targeted subgroups of participants (pre/peri-menopausal women, post-menopausal women, never smokers, non-movers, and never-smoking non-movers). However, elevated risks for hormone-responsive-negative tumors were observed for higher exposure to cadmium compounds and possibly inorganic arsenic among never-smoking non-movers. Conclusion Long-term low-dose exposure to ambient cadmium compounds or possibly inorganic arsenic may be a risk factor for breast cancer.

Breast Cancer Risk in Relation to Ambient Air Pollution Exposure at Residences in the Sister Study Cohort

“…Multiple studies (2, 3), but not all (4, 7), found that exposure to traffic-related air pollutants, particularly NO 2 , increased breast cancer risk. A potential explanation for differences among studies could be differing proportions of ER/PR subtypes, if as our data suggest, NO 2 is only associated with ER+/PR+ breast cancer.…”

“…Most notably, a 2010 case-control study reported a 1.3-fold increased risk of breast cancer (95% CI of OR: 1.0–1.7) for every 5 ppb increase in NO 2 assessed via a land-use regression spatial model (3). The California Teachers Study recently reported an increased risk for ER−/PR− breast cancer associated with endocrine disruptors present in ambient air, namely cadmium compounds and inorganic arsenic (4). However, to date, relatively few studies have investigated the link between air pollution and breast cancer subtypes.…”

Association between air pollution and mammographic breast density in the Breast Cancer Surveilance Consortium

“…In analyses stratified by tumor subtype, some of the air pollutants were associated with estrogen-receptor-positive and progesterone-receptor-positive (ER+ and PR+) tumors; other constituents have been associated with receptor-negative subtypes only. Positive associations have been identified between ER+/PR+ tumors and ambient levels of NO 2 , acrylamide, benzidine, carbon tetrachloride, ethylidene dichloride, and vinyl chloride, and between ER-negative/PR-negative (ER-/PR-) subtypes and ambient levels of benzene, cadmium, and inorganic arsenic [19, 21, 22]. …”

Determinants of serum cadmium levels in a Northern Italy community: A cross-sectional study

“…In particular, the role of diet, particularly for non-smoking subjects (European Food Safety Authority, 2012), and outdoor pollution due to industrial emissions, fossil fuel combustion, solid waste incineration and traffic exhausts is still not well defined, since little epidemiologic evidence is available (Hogervorst et al, 2007;Liu et al, 2015). In this study, we aimed to assess Cd exposure in the general population of a Northern Italian community, and in addition we sought to identify the independent role of three sources of Cd exposure: smoking habits, diet and outdoor air pollution.…”