Depending on where and how fat accumulates, obese women may be at an increased risk of developing certain subtypes of breast cancer, according to a study published in The Oncologist.1
For this study, researchers assessed 1316 patients with newly diagnosed breast cancer whose estrogen receptor (ER) and progesterone receptor (PR) statuses were confirmed. Body mass index (BMI), waist-hip ratio (WHR), current weight, standing height, waist circumference (WC), and hip circumference were measured.
The results of the study showed that in all cases, BMI, body weight, WC, and WHR are positively correlated with breast cancer risk.
Women who weighed more than 62 kg had a 21% (odds ratio [OR], 1.21; 95% CI, 1.02-1.45) and 34% (OR, 1.34; 95% CI, 1.03-1.73) increased risk of developing ER-positive (ER+)/PR-positive (PR+) and ER-negative (ER-)/PR-negative (PR-) breast cancer, respectively, compared with women who weighed less than 62 kg.
WC was also significantly associated with an increased risk of developing ER+/PR+ (P < .001) and ER-/PR- (P = .004) breast cancer.
High BMI trended towards an increased risk for both ER+/PR+ and ER-/PR-, but was associated significantly only with an increased risk for ER+/PR+ subtypes.
Women with a WHR greater than 0.85 had an increased risk of 64% (OR, 1.64; 95% CI, 1.23-2.18) only for ER-/PR- subtypes.
Premenopausal women with a high BMI had an increased risk of developing ER+/PR+ and ER-/PR- breast cancers, and WHR had an inverse relationship with ER+/PR- and a positive relationship with ER-/PR- subtypes. Postmenopausal women with a WHR greater than 0.85 were at increased risk of ER-/PR- breast cancer.
Noting that current chemopreventive strategies for breast cancer provide benefit only for patients with ER+ breast cancer, the authors concluded that “the results suggest that different chemoprevention strategies should be considered in selected individuals.”
- Wang F, Liu L, Cui S, et al. Distinct effects of BMI and WHR on risk of breast cancer by joint estrogen and progestogen receptor status: results from a case-control study in Northern and Eastern China and implications for chemoprevention. Oncologist. 2017 Sep 14. doi: 10.1634/theoncologist.2017-0148 [Epub ahead of print]