Body Size Throughout Adult Life Influences Postmenopausal Breast Cancer Risk among Hispanic Women: The Breast Cancer Health Disparities Study

Background: Few studies have assessed the association of body size with postmenopausal breast cancer risk in Hispanic women. Findings are inconsistent and appear to contradict those reported for non-Hispanic white (NHW) women. Methods: We pooled interview and anthropometric data for 2,023 Hispanic and 2,384 NHW women from two U.S. population-based case-control studies. Using logistic regression analysis, we examined associations of overall and abdominal adiposity with risk of postmenopausal breast cancer defined by estrogen receptor (ER) and progesterone receptor (PR) status. Results: Weight gain was associated with increased risk of ER+ PR+ breast cancer in Hispanics not currently using menopausal hormone therapy (HT), but only among those with a low young-adult body mass index (BMI). In the subset of Hispanics with data on genetic ancestry, the association with weight gain was limited to women with lower Indigenous American ancestry. Young-adult BMI was inversely associated with both ER+PR+ and ER+ PR+ breast cancers for both ethnicities combined, with similar, although nonsignificant, inverse trends in Hispanics and NHWs. Among all Hispanics, regardless of HT use, height was associated with risk of ER+PR+ breast cancer and hip circumference with risk of breast cancer overall. Conclusions: Body size throughout adult life is associated with breast cancer risk among postmenopausal Hispanic women, as has been reported for NHW women. Associations were specific for breast cancer subtypes defined by hormone receptor status. Impact: Avoiding weight gain and maintaining a healthy weight are important strategies to reduce the risk of postmenopausal ER+PR+ breast cancer, the most common breast cancer subtype. (C) 2014 AACR.