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

Abstract

Background Some but not all past studies reported associations between components of air pollution and breast cancer, namely fine particulate matter ≤ 2.5 μm (PM2.5) and nitrogen dioxide (NO2). It is yet unclear whether risks differ according to estrogen receptor (ER) and progesterone receptor (PR) status. Methods This analysis includes 47,591 women from the Sister Study cohort enrolled from August 2003-July 2009, in whom 1,749 invasive breast cancer cases arose from enrollment to January 2013. Using Cox proportional hazards and polytomous logistic regression, we estimated breast cancer risk associated with residential exposure to NO2, PM2.5, and PM10. Results While breast cancer risk overall was not associated with PM2.5 (Hazards ratio [HR] = 1.03; 95% CI: 0.96–1.11), PM10 (HR = 0.99; 95% CI: 0.98–1.00), or NO2 (HR = 1.02; 95% CI: 0.97–1.07), the association with NO2 differed according to ER/PR subtype (p = 0.04). For an interquartile range (IQR) difference of 5.8 parts per billion (ppb) in NO2, the relative risk (RR) of ER+/PR+ breast cancer was 1.10 (95% CI: 1.02–1.19), while there was no evidence of association with ER−/PR− (RR=0.92; 95% CI: 0.77–1.09; pinteraction=0.04). Conclusions Within the Sister Study cohort, we found no significant associations between air pollution and breast cancer risk overall. But we observed an increased risk of ER+/PR+ breast cancer associated with NO2. Impact Though these results suggest there is no substantial increased risk for breast cancer overall in relation to air pollution, NO2, a marker of traffic related air pollution, may differentially affect ER+/PR+ breast cancer.

Long-term Exposure to Fine Particulate Matter and Breast Cancer Incidence in the Danish Nurse Cohort Study

“…We found moderately stronger associations in pre-than in postmenopausal women, in agreement with two studies (2,3). We present novel findings of enhanced association between PM 2.5 Ours and most other recent studies (2-5) examined air pollution exposure during adulthood, relatively close to breast cancer onset, which may not be the relevant exposure window for the development of breast cancer.…”

“…We found no association between long-term exposure to air pollution and breast cancer incidence in DNC in agreement with other cohort (2,3,5), and in contrast to a case-control study (2). We found moderately stronger associations in pre-than in postmenopausal women, in agreement with two studies (2,3).…”

“…Experimental data provide some evidence of a link between a number of carcinogens in air pollution and breast cancer, including polycyclic aromatic hydrocarbons, which can cause mammary tumors in laboratory animals (1). Epidemiologic data are mixed, with case-control studies (2) detecting association and cohort studies (3)(4)(5) finding no association between air pollution and breast cancer incidence. The latest Canadian case-control study found a 26% to 32% increased risk of premenopausal, and 7% to 10% increased risk of postmenopausal breast cancer, per 10 ppb increase in nitrogen dioxide (NO 2 (5).…”

“…The latest Canadian case-control study found a 26% to 32% increased risk of premenopausal, and 7% to 10% increased risk of postmenopausal breast cancer, per 10 ppb increase in nitrogen dioxide (NO 2 (5). Only two studies had data on PM 2.5 and PM 10 (3,4). Here, we examined the association between long-term exposure to PM 2.5 , PM 10 , and NO 2 at the residence and incidence of breast cancer in the nationwide, prospective Danish Nurse Cohort (DNC).…”

Residential exposure to vehicular traffic-related air pollution during childhood and breast cancer risk

“…Case-control studies of nitrogen dioxide (NO 2 ) (Crouse et al, 2010; Hystad et al, 2015) have reported positive associations, while prospective cohort studies (Andersen et al, 2016; Reding et al, 2015) have reported null or weak positive associations. For instance, a Canadian case-control study reported an odds ratio (OR) of 1.31 (95% confidence interval (CI): 1.00, 1.71) for every 5 ppb increase in NO 2 (Crouse et al, 2010), while a study examining the association between breast cancer risk and air pollution at the enrollment residence of Sister Study cohort participants did not find an overall increase in breast cancer risk, however, a modest positive association was observed between NO 2 exposure and estrogen/progesterone receptor positive breast cancer (risk ratio = 1.10, 95% CI: 1.02,1.19 for an interquartile range difference of 5.8 parts per billion) (Reding et al, 2015). Only one study, a US-based case-control study, evaluated the association between breast cancer and long-term vehicular traffic-related PAH exposure, reporting an OR of 1.44 (95% CI: 0.78, 2.68) for the top 5% level of exposure as compared to below the median (Mordukhovich et al, 2016).…”