Type 2 diabetes is associated with increased breast cancer risk, especially in postmenopausal women. The high level of circulating insulin (hyperinsulinemia) found in type 2 diabetes appears to promote breast cancer both indirectly and directly by acting as a growth promoter.

Regular moderate exercise appears to lower breast cancer risk by reducing inflammation, lowering circulating estradiol and androgen levels, and inducing beneficial changes in insulin levels and insulin-related pathways. Exercise also might boost immunity and positively influence the regulation of tumor suppressor genes. Now a new study has reported that regular exercise reduces breast cancer risk among women with type 2 diabetes.

Latest research finds exercise reduces breast cancer risk in diabetic women

The case-control study referenced at the beginning of this news article was designed to investigate the influence of moderate intensity physical activity on the association between type 2 diabetes and risk of breast cancer in Mexican women. The study included 1,000 breast cancer patients and 1,074 cancer-free controls. Study participants provided blood samples, as well as data concerning health, diet, and physical activity.

The association between diabetes and breast cancer risk was found to decrease with increasing levels of moderate intensity physical activity. When study participants were divided into three groups according to level of physical activity, the women in the lowest exercise group had approximately five times the breast cancer risk as those in the highest group. Compared to the women in the lowest exercise group, increased risk was seen in premenopausal women with the highest serum C-peptide (a marker of insulin production in the body), insulin like growth factor-1 (IGF-1), and IGF-1 binding protein 3 levels. The authors conclude that moderate physical activity can substantially lower the increased risk of breast cancer in diabetic women.

Please see our articles on exercise and type 2 diabetes for more information.