Dioxin emissions from a municipal solid waste incinerator and risk of invasive breast cancer: a population-based case-control study with GIS-derived exposure

Abstract

BackgroundTo date, few epidemiologic studies have examined the relationship between environmental PCDD/F exposure and breast cancer in human populations. Dioxin emissions from municipal solid waste incinerators (MSWIs) are one of the major sources of environmental dioxins and are therefore an exposure source of public concern. The purpose of this study was to examine the association between dioxins emitted from a polluting MSWI and invasive breast cancer risk among women residing in the area under direct influence of the facility.MethodsWe compared 434 incident cases of invasive breast cancer diagnosed between 1996 and 2002, and 2170 controls randomly selected from the 1999 population census. A validated dispersion model was used as a proxy for dioxin exposure, yielding four exposure categories. The latter were linked to individual places of residence, using Geographic Information System technology.ResultsThe age distribution at diagnosis for all cases combined showed a bimodal pattern with incidence peaks near 50 and 70 years old. This prompted us to run models separately for women aged 20–59 years, and women aged 60 years or older. Among women younger than 60 years old, no increased or decreased risk was found for any dioxin exposure category. Conversely, women over 60 years old living in the highest exposed zone were 0.31 time less likely (95% confidence interval, 0.08–0.89) to develop invasive breast cancer.ConclusionBefore speculating that this decreased risk reflects a dioxin anti-estrogenic activity with greater effect on late-onset acquired breast cancer, some residual confounding must be envisaged.

Aryl Hydrocarbon Receptor Regulates Cell Cycle Progression in Human Breast Cancer Cells via a Functional Interaction with Cyclin-Dependent Kinase 4

“…This switch-like function is compatible with the existing model of the role of the AHR in the cell cycle while extending the model to provide a mechanism by which the receptor can also facilitate cell cycle progression. Within mammary epithelial cells, the integrated model can explain both the lack of mammary development in the AHR knockout mice, in which facilitation of cell cycle progression by the receptor is absent (Hushka et al, 1998), as well as the epidemiological and rodent data demonstrating the inhibition of mammary tumorigenesis by exogenous AHR ligands (Bertazzi et al, 1997;National Toxicology Program, 2006;Viel et al, 2008).…”

Evaluating Breast Cancer Risk under Exposure to Environmental Estrogen-Like Chemicals

“…The result showed increasing dioxin intake levels associated with declining breast cancer risk in post-menopausal women with ER-negative/PR-negative tumors [59]. In contrast, epidemiological case-control studies found no apparent association between dioxin exposure and breast cancer [80][81].…”

Dioxins and Human Toxicity

“…A study from Russia reported higher risk of breast cancer among women living in the area of a chemical plant which contaminated the surrounding environment with dioxins (62). However, Viel et al (63) did not fi nd an association between breast cancer risk in younger women and exposure to dioxins emitted from a local incinerator. Moreover, the study showed a decreased risk in older women who lived in the area, which was highly polluted with dioxins.…”

“…Some epidemiological studies investigated the relationship between dioxin exposure and breast cancer risk (61)(62)(63). A study which included women from Seveso found a signifi cantly increased risk of breast cancer associated with increased TCDD in serum (61).…”