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Obesity is a known risk factor for various cancers, and its rise over the past few decades has contributed to a rise in hormone receptor positive breast cancer rates that is greater in Black women than white women. At the same time, as overall breast cancer mortality rates have declined, the decline has been less pronounced in Black women, producing a 40% mortality gap.

UNC Lineberger’s Kirsten Nyrop, PhD.

An analysis of women with early breast cancer, UNC Lineberger Comprehensive Cancer Center’s Kirsten Nyrop, PhD, and her colleagues found Black women had higher rates of obesity and other health conditions that can affect prognosis and survival, compared with white women. The findings were published in Cancer, a peer-reviewed journal of the American Cancer Society.

Cancer disparities in study findings

The study team analyzed health data for 548 patients treated at their hospital for early breast cancer. They found 62% of Black patients and 32% of white patients were obese, and higher percentages of Black women had obesity-related comorbidities, such as hypertension, diabetes and high cholesterol, compared to white women. Yet, despite significant differences in the prevalence of obesity and comorbidities, there were no differences between Black and white patients in treatment decisions with regard to type of surgery, chemotherapy, radiation or endocrine therapy.

“Findings from this study need to be considered within the larger context of the cancer-obesity link and the disparate impact of the obesity epidemic on communities of color in the United States,” said Nyrop, assistant professor in UNC School of Medicine’s division of oncology.

“Early breast cancer is highly treatable, and survival rates have improved steadily due to treatment advances and early detection through mammograms,” Nyrop said. “However, the high rates of obesity, overall comorbidities, and obesity-related comorbidities observed among women with early breast cancer—especially among Black women—can contribute to disparities in overall survival of these patients.”

Nyrop also recognized that the rates of many cancers impacted by obesity are higher in Black women, as are the rates of numerous obesity-related conditions such as diabetes and hypertension. “As the COVID-19 pandemic has glaringly underscored, there is an urgent need to address the systemic and socioeconomic aspects of obesity that disproportionately affect minority communities in the U.S. if we are to reverse health disparities.”

Authors and Disclosures

In addition to Nyrop, the study’s other authors are Emily Damone, UNC Gillings School of Global Public Health; Allison M. Deal, MS, Addison (Tucker) Brenizer, Amy Wheless, MA, UNC Lineberger; Lisa Carey, MD, and Hyman B. Muss, MD, UNC Lineberger and UNC School of Medicine;  Michael Lorentsen, MD, UNC School of Medicine; Shlomit Shachar, MD, Rambam Health Campus, Haifa, Israel; and Grant Williams, MD, School of Medicine, University of Alabama at Birmingham

The study was funded in part by grants from the Breast Cancer Research Foundation, the NCI Breast Cancer Specialized Program of Research Excellence (CA58223) and the University Cancer Research Fund.

—Kim Morris, UNC School of Medicine, Department of Medicine