Moderate-intensity physical activity ameliorates the breast cancer risk in diabetic women.

Abstract

To evaluate the association between self-reported diabetes and the risk of breast cancer (BC) and its interaction with moderate-intensity physical activity in pre- and postmenopausal Mexican women. A population-based case-control study was conducted using 1,000 incident case subjects and 1,074 control subjects. Blood samples and information on health, diet, physical activity, and anthropometric measurements were obtained. The association between diabetes and BC risk decreased with increasing tertiles of moderate-intensity physical activity (odds ratio [OR] = 4.9 [95% CI 2.3-10.8]; 3.0 [1.3-6.9]; and 1.0 [0.1-9.2], respectively, for each tertile) (test for interaction = 0.04). Compared with the women in the lowest tertiles, increased risk was observed in those premenopausal women with the highest serum C-peptide, IGF-1, and IGF-1 binding protein 3 levels. Moderate-intensity physical activity can substantially ameliorate the increased BC risk in diabetic women.