Treating Diabetes Can Reduce a Woman's Risk for Breast Cancer

A study conducted in Denmark identified an inverse association between controlling diabetes, through diet or oral medications, and breast density.

An abstract presented at the ongoing meeting of the European Breast Cancer Conference, organized by the European CanCer Organisation, shared findings that diabetes treatment decreases mammographic density—one of the strongest risk factors for breast cancer.

The study, conducted in Denmark, recruited 5644 women (average age 56 years, a majority were postmenopausal) into the Danish Diet, Cancer and Health study group. The women had undergone mammographic screening between 1993 and 2001. The study identified 137 women with diabetes and 3180 women who were categorized as having mixed or dense breasts.

Importantly, the inverse association between controlling diabetes and breast density held true, whether women used medication or followed a strict dietary guideline to reduce their blood glucose levels. The study found that 44 women who controlled their diabetes with diet alone and 62 who took oral medication, all had low breast density. Interestingly, women administering insulin injections had increased odds of having mixed or dense breasts, the study found. Notably, these associations were not influenced by the women’s menopausal status or their body mass index.

The study’s lead author, Zorana Jovanovic Andersen, PhD, associate professor of Epidemiology at the University of Southern Denmark, explained in a statement, “Diabetes is associated with an increased risk of breast cancer, but the exact mechanisms which bring but the exact mechanisms which bring this about are still unclear. One of the characteristics of cancer cells is their ability to grow rapidly and uncontrollably, and to resist the programmed death that occurs in non-cancer cells. Therefore, growth factors are critical to cancer development and progression. We know that insulin is an important growth factor for all body tissues, and even if we do not know exactly how it affects the development of cancer cells, it is also highly plausible that it increases breast density.”

Andersen warns though that these findings do not mean that insulin increases the risk of breast cancer—this is something that the authors plan to evaluate in future studies.

Diabetetologia

The association between diabetes and increased risk for certain organ cancers was recently published in —the analysis found increased risks of cancer of the stomach, liver, pancreas, endometrium, and kidney.