Body Composition and Breast Cancer Survival in African American Women
Obesity is associated with both increased risk of breast cancer and increased risk of death after breast cancer diagnosis. Understanding the association between body composition, including the amount and distribution of fat in the body, and breast cancer is important.
Most studies of this association have used body mass index (BMI) to estimate body fat and composition and have not thoroughly evaluated other measurements, such as waist circumference, waist-to-hip ratio, percent body fat (e.g., visceral or subcutaneous) or fat mass index, to identify women at higher risk of developing breast cancer or of death after a breast cancer diagnosis. BMI may not be a good marker of body composition, particularly in Black/African American women, who have higher rates of obesity and a higher risk of death after breast cancer diagnosis than do women from other racial or ethnic populations.
The increased risk experienced by Black/African American women in developing obesity and breast cancer reflect unique challenges experienced by this population in access to healthy food, physical activity spaces, healthcare, and potential biases in diagnosis and treatment of both conditions. When evaluating other measures of body composition, an NIMHD-supported study found additional clinical tools can be used to identify Black/African American women with a higher risk of death after being diagnosed with breast cancer. A better understanding of the most appropriate body composition measures to evaluate risk of developing and death from breast cancer after diagnosis in Black/African American women could ultimately help reduce this health disparity.
The researchers analyzed data from 1,891 women in New Jersey who self-identified as Black or African American and had been diagnosed with breast cancer. They measured the women’s height, weight, and waist and hip circumference and calculated their body mass index (BMI) and waist-to-hip ratio (WHR). They also used a special scale to measure the amount of fat in the women’s bodies and calculated fat mass index (FMI).
The women were interviewed each year for five years after their cancer diagnosis. The researchers also obtained additional information about the participants’ diagnosis and outcomes from medical records and data from the New Jersey State Cancer Registry.
During the study period, from 2006 to 2020, 286 (14%) of the women died. About 60% of the deaths were attributed to complications arising from breast cancer. The researchers found that women with the highest WHRs, had a 61% higher risk of dying from any cause and a 68% higher risk of dying from breast cancer compared to women with the lowest WHRs. The findings were similar for waist circumference alone, FMI, and total percent body fat. Women with higher BMIs also had a higher risk of dying than women with lower BMI, but the difference in risk was smaller.
The study suggests that using these clinically useful measures of body composition beyond BMI, such as WHR and waist circumference, could help physicians identify Black/African American women who are at higher risk of death after a breast cancer diagnosis. Similar studies need to be conducted in women from other racial and ethnic groups who are at higher risk of death after a breast cancer diagnosis. The findings could be especially useful for primary care physicians and health care facilities with limited resources. Further research is needed to better understand the reasons for the associations between obesity and breast cancer risk and survival.
Bandera, E.V., Qin, B., Lin, Y., Zeinomar, N., Xu, B., Chanumolu, D., . . . Hong, C. (2021). Association of body mass index, central obesity, and body composition with mortality among Black breast cancer survivors. JAMA Oncology, 7(8), 1–10. doi: 10.1001/jamaoncol.2021.1499.
Page updated January 27, 2022