Carcinogenic industrial air pollution and postmenopausal breast cancer risk in the National Institutes of Health AARP Diet and Health Study

Our plain-English summary of Carcinogenic industrial air pollution and postmenopausal breast cancer risk in the National Institutes of Health AARP Diet and Health Study, by J.M. Madrigal, C.N. Pruitt, J.A. Fisher, et al (Environment International, 2024).

The study

• Authors: J.M. Madrigal, C.N. Pruitt, J.A. Fisher, L.M. Liao, B.I. Graubard, G.L. Gierach, D.T. Silverman, M.H. Ward, R.R. Jones
• Journal: Environment International
• Published: 2024;191:108985
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Chemicals emitted from industrial facilities include known or suspected mammary carcinogens and endocrine disruptors, but epidemiologic studies are limited. We evaluated associations between air emissions of multiple carcinogenic chemicals and postmenopausal breast cancer risk in a large prospective U.S.

Methods: We used the U.S. Environmental Protection Agency's Toxics Release Inventory to estimate historical airborne emissions (1987-1995) of 19 known and probable carcinogens for participants enrolled (1995-1996) in the NIH-AARP Diet and Health Study. Among 170,402 women, 15,124 breast cancers were diagnosed through 2018. We constructed inverse distance- and wind-weighted average emissions metrics within 1, 2, 5, and 10 km of the enrollment address for each chemical. We estimated multivariable adjusted HRs and 95 % CIs for categories (quartiles, tertiles, medians) of each chemical in association with breast cancer overall and separately by type (invasive, ductal carcinoma in situ) and estrogen receptor (ER) status.

Results: We observed an association between benzene emissions and breast cancer risk that was strongest at 1 km (HRQ4 vs. non-exposed = 2.06, 95 %CI: 1.34-3.17; p-trend = 0.001). The magnitude of the association weakened with increasing distance (2 km HRQ4 vs. non-exposed = 1.17, 95 %CI=0.92-1.49; p-trend = 0.19; 5 km HRQ4 vs. non-exposed = 1.05, 95 %CI=0.94-1.16; p-trend = 0.37; 10 km HRQ4 vs. non-exposed = 0.95, 95 %CI=0.89-1.02; p-trend = 0.19) and appeared to be most relevant for invasive rather than intraductal disease. Overall risk was also elevated for vinyl chloride at 5 km (HR≥median vs. non-exposed = 1.20, 95 %CI=1.01-1.43; p-trend = 0.04), but not 2 km or 10 km. We observed suggestive associations for asbestos, trichloroethylene, and styrene in different subgroup analyses, but risk patterns were not clear across distances. Associations with other chemicals were generally null, with limited evidence of heterogeneity by disease type or ER status.

Conclusions: An increased risk of breast cancer associated with relatively high levels of industrial benzene emissions warrants additional study, particularly among participants with diverse sociodemographic characteristics that live in areas with higher density of industrial facilities.

Published by Elsevier Ltd.

In plain English

This prospective cohort study followed 170,402 postmenopausal women in the NIH-AARP Diet and Health Study. They were enrolled in 1995 to 1996 in six U.S. states and two metropolitan areas, and 15,124 were diagnosed with breast cancer through 2018. Using the federal Toxics Release Inventory, the authors estimated industrial air emissions of known and probable carcinogens, including asbestos and benzene, released from 1987 to 1995 within 1, 2, 5 and 10 km of each woman's home. Women with the highest benzene emissions within 1 km had a hazard ratio of 2.06 (95% CI 1.34 to 3.17) compared with unexposed women, and the association weakened with distance. For asbestos, risk was elevated in the highest tertile within 10 km (HR 1.11, 95% CI 1.02 to 1.20) but not within 5 km or 2 km. At 10 km the asbestos association appeared for invasive cancer but not for ductal carcinoma in situ. Fewer than 1,000 women lived within 2 km of an asbestos source. The authors concluded that high industrial benzene emissions may be associated with increased breast cancer risk. They did not correct their p-values for multiple testing.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: prospective cohort study
• Who was studied: 170,402 postmenopausal women in the NIH-AARP Diet and Health Study. They were AARP members aged 50 to 71, enrolled 1995 to 1996 in California, Florida, Louisiana, New Jersey, North Carolina, Pennsylvania, Atlanta and Detroit. 15,124 incident breast cancers were diagnosed over a median of 22 years of follow-up, to December 31, 2018.
• Exposure: Residential exposure to industrial air emissions (1987 to 1995) reported to the U.S. EPA Toxics Release Inventory of IARC Group 1 and Group 2A carcinogens, including asbestos (fiber type not specified), benzene and vinyl chloride. Exposure was measured as an inverse distance-weighted, wind-adjusted average emissions index within 1, 2, 5 and 10 km of the enrollment address.
• Main results:
  • Benzene, all breast cancer, highest quartile compared with non-exposed women, within 1 km: HR 2.06 (95% CI 1.34 to 3.17), p-trend 0.001. The association weakened at 2, 5 and 10 km.
  • Asbestos, all breast cancer, highest tertile compared with non-exposed women: within 10 km HR 1.11 (95% CI 1.02 to 1.20), p-trend 0.01. Within 5 km HR 0.98 (95% CI 0.84 to 1.14), and within 2 km HR 1.22 (95% CI 0.86 to 1.73).
  • Asbestos within 10 km, highest tertile compared with non-exposed women: invasive breast cancer HR 1.15 (95% CI 1.06 to 1.26), p-trend 0.003. Ductal carcinoma in situ HR 0.95 (95% CI 0.77 to 1.19), p-trend 0.71. p-heterogeneity 0.35.
  • Fewer than 1,000 women lived within 2 km of asbestos sources.
  • Vinyl chloride within 5 km, at or above the median compared with non-exposed women: HR 1.20 (95% CI 1.01 to 1.43), p-trend 0.04. There was no association within 2 km or 10 km.
• The authors' conclusion: The authors concluded that relatively high levels of airborne industrial benzene emissions may be associated with increased breast cancer risk among women living close to these facilities.
• Limitations the authors state:
  • The authors assumed women lived at their enrollment address throughout the historical exposure period.
  • Time away from home and exposure at other places, such as the workplace, were not accounted for.
  • Not all facilities report to the Toxics Release Inventory, and emissions are self-reported estimates.
  • Few participants had emissions close to the home, which limited statistical power.
  • One-third of women were missing estrogen receptor status.
  • The p-values were not corrected for multiple testing.

Topics

Medical terms in this study, explained in our Lexicon: Carcinogenic, Carcinoma.

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