New study to measure effects of environmental exposure on young women's breasts

A University of Massachusetts Amherst cancer epidemiologist has received a $462,000 grant from the National Institutes of Health to expand her research into the effects of endocrine-disrupting chemicals on the breast density of college-age women. High breast density is a strong risk factor for breast cancer.

A previous study focusing on older women found that exposure to plasticizers such as phthalates and bisphenol A (BPA), as well as related compounds found in common household and personal care items, can increase breast density. Studies with premenopausal women in Mexico and Canada have noted associations between environmental exposures and breast cancer risk.

Susan Sturgeon, whose research focuses on the epidemiology of hormonally related cancers, hopes the study will shed new light on the suspected link between environmental exposure, breast density and breast cancer risk in young women.

Breast density in young women may be as strongly associated with subsequent breast cancer risk as mammographic breast density in older women."

Susan Sturgeon, professor of biostatistics and epidemiology, School of Public Health and Health Sciences

The study will measure the effects of environmental exposure on the breasts of young women "during a window of potential increased susceptibility," Sturgeon says. Animal studies suggest mammary cells are more susceptible to environmental chemicals during breast development up to and through pregnancy.

"The link between environmental chemicals and breast cancer risk is not clear, and it is challenging to study. Measuring breast density by magnetic resonance imaging (MRI) makes this kind of study possible in younger women, eliminating radiation risk from mammography," Sturgeon says.

Sturgeon will recruit 100 undergraduate female students at UMass Amherst, who have never given birth, for the study, which will be conducted at the UMass Institute for Applied Life Sciences' Models to Medicine Center.

Environmental chemical exposure is thought to affect breast density by increasing levels of estrogen and inflammation. Sturgeon and colleagues will measure participants' urinary levels of BPA, BPS, BPF, seven phthalate metabolites, oxybenzone, four parabens, triclosan, triclocarbon and two other phenols in a pooled urine specimen from 24-hour collections on three spaced days prior to computerized MRI in IALS' Human Magnetic Resonance Center. The urine collection requires participants to collect all of their urine over a 24-hour period because exposure to these chemicals can vary substantially throughout the day.

"The study is innovative because of the multiple time-point exposure measurements, the use of the urinary matrix to measure these chemicals and computerized magnetic resonance imaging to measure breast density in young women," Sturgeon says.

One of the important goals of this grant is to expose students to research, she adds. Both undergraduate and graduate students are involved, including Jennifer Carroll, Hannah Guard, Jessica Daum, Ashley Moineau and Emily Fernandes.

"Working on this study has been an incredible learning experience for me," says Guard, a junior from Marion, Massachusetts, double-majoring in biochemistry and molecular biology, as well as public health. "While working collaboratively with both professors and students, this study has given me the opportunity to gain hands-on experience in participant recruitment, data collection and lab work, truly enhancing my educational experience at UMass beyond the classroom."