UMass Epidemiologist Leads Study of Possible Link Between Phthalates, Breast Cancer Risk

Possible Link Between Phthalates and Breast Cancer Risk

An epidemiologist at the University of Massachusetts Amherst has received a $1.5 million grant from the National Institute of Environmental Health Sciences to study whether phthalates affect human breast cancer risk.

Prof. Katherine Reeves of the UMass School of Public Health will lead the three-year grant to investigate a possible relationship between phthalates—widely used plasticizing and solvent chemicals—and breast cancer risk, the (Greenfield, Mass.) Recorder reports.

Phthalates are found in such products as cosmetics, shampoo, flooring and medical tubing, plastic packaging (including food and blood-storage containers), and some children’s toys. They are added to products increase flexibility, transparency, durability, and longevity. Reeves and her colleagues will study phthalate metabolites, products found in urine samples after the chemicals have passed through the body. Measurable phthalate levels are found in nearly 100 percent of the United States population though the levels vary widely, according to the Recorder. Phthalate metabolites have been reported in human breast milk. Until now, only a handful of small studies have looked at whether phthalates affect human breast cancer risk and none have measured phthalate metabolites before a cancer diagnosis.

The research team includes UMass Amherst biologist Thomas Zoeller, an expert in endocrine-disrupting chemicals, epidemiologist Sue Hankinson, and biostatistician Carol Bigelow, who, along with Reeves, will analyze levels of 11 phthalate metabolites in urine samples from 500 women diagnosed with invasive beast cancer after Year 3 of follow-up and in 1,000 healthy matched controls in a prospective study within the Women’s Health Initiative, the Recorder reports. Because the samples “were given many years before any sign of disease appeared,” this study will give “much stronger evidence in terms of causality than studies using another design,” Reeves says. Researchers will have three stored urine samples—from baseline, Year 1 and Year 3—for analysis, and they will be able to address variation in phthalate exposure. They will be able to get an idea of a woman’s typical or average exposure to phthalates.

At this point, the scientific evidence on phthalate exposure risk is unclear and Reeves says with this study the researchers hope to provide either “reassurance or solid evidence of cause for concern,” according to the Recorder.

The Environmental Protection Agency (EPA) is concerned about phthalates because of their toxicity and the evidence of pervasive human and environmental exposure to these chemicals. Phthalates are used in a wide variety of industrial and consumer products, many of which pose potentially high exposure. Phthalates have been detected in food (they are used in coatings in food packaging) and also measured in humans. Studies have shown adverse effects on the development of the reproductive system in male laboratory animals. According to the EPA, several studies have shown associations between phthalate exposures and human health, although no causal link has been established. Recent scientific attention has focused on whether the cumulative effect of several phthalates may multiply the reproductive effects in the organism exposed.