Authors: Trang VoPham*, Harvard T.H. Chan School of Public Health & Brigham and Women's Hospital, Kimberly A. Bertrand, Slone Epidemiology Center at Boston University, Rena R. Jones, National Cancer Institute, Natalie DuPré, Harvard T.H. Chan School of Public Health & Brigham and Women's Hospital, Peter James, Harvard Medical School and Harvard Pilgrim Health Care Institute, Verónica Vieira, University of California, Irvine, Rulla M. Tamimi, Harvard T.H. Chan School of Public Health, Brigham and Women's Hospital, & Harvard Medical School, Jaime E. Hart, Harvard T.H. Chan School of Public Health, Brigham and Women's Hospital, & Harvard Medical School, Mary H. Ward, National Cancer Institute, Francine Laden, Harvard T.H. Chan School of Public Health, Brigham and Women's Hospital, & Harvard Medical School
Topics: Medical and Health Geography, Environment, Geographic Information Science and Systems
Keywords: environmental exposure, epidemiology, dioxin, breast cancer
Session Type: Paper
Start / End Time: 8:00 AM / 9:40 AM
Room: Studio 6, Marriott, 2nd Floor
Presentation File: No File Uploaded
Background: Dioxins are persistent organic pollutants generated from combustion of chlorinated compounds. The International Agency for Research on Cancer has classified 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a group 1 human carcinogen. Dioxins are hypothesized to impact cancer risk via endocrine disruption. Occupational and dietary dioxin exposure have been inconsistently associated with breast cancer. Objective: To prospectively examine the association between residential proximity to dioxin-emitting facilities and invasive breast cancer risk in the Nurses’ Health Study II (NHSII). Methods: NHSII includes U.S. female registered nurses who completed self-administered questionnaires biennially since 1989. Self-reported breast cancer was confirmed from medical records. Dioxin exposure was estimated by determining proximity, duration of residence, and emissions of dioxin-emitting facilities located within 3, 5, and 10 km of geocoded residential addresses updated throughout follow-up. Cox regression models adjusted for established breast cancer risk factors were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: From 1989 to 2013, 3,956 invasive breast cancer cases occurred among 112,668 participants. Residence within 10 km of any dioxin-emitting facility was associated with an increased risk for invasive breast cancer (adjusted HR 1.07, 95% CI 1.00-1.14). Residence within 10 km of any municipal solid waste incinerator was positively associated with invasive breast cancer risk (HR 1.13, 95% CI 1.02-1.26). Results within 3 and 5 km and according to duration and emissions showed similar associations. Conclusions: We observed statistically significant positive associations between residential proximity to dioxin-emitting facilities, particularly municipal solid waste incinerators, and invasive breast cancer risk.