Diabetes Treatment Alters Breast Density

Breast tissue density may decrease among women with diabetes that is controlled with diet or oral medications, but may increase among women who use insulin, according to a presentation at the 10^th European Breast Conference, which took place in the Netherlands March 9 to 11.

Researchers from Denmark performed a prospective cohort study to determine if diabetes and diabetes treatment were associated with breast tissue density. A total of 5,703 women, mean age of 56, participated in the study, undergoing mammography screening between 1993 and 2001; 4,501 participants were postmenopausal. Among the 5,703 women, 137 (2.4%) had diabetes, and 3,180 (56.3%) had breasts categorized as mixed or dense.

The results showed that having diabetes was significantly inversely associated with having mixed/dense breasts, in both the crude model and after adjustment for adiposity and other risk factors, the researchers said. Similar inverse associations were observed for 44 women with diabetes controlled by diet only, and 62 who took oral medications for diabetes control. More women who used insulin, however, seemed to have mixed/dense breast tissue. Menopausal status and body mass index did not seem to have an effect on density.[[{"type":"media","view_mode":"media_crop","fid":"47176","attributes":{"alt":"Zorana Jovanovic Andersen","class":"media-image media-image-right","id":"media_crop_6942518211310","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5540","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 180px; width: 180px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":"Zorana Jovanovic Andersen","typeof":"foaf:Image"}}]]

"Diabetes is associated with an increased risk of breast cancer, but the exact mechanisms which bring this about are still unclear, Dr. Zorana Jovanovic Andersen, associate professor of epidemiology at the University of Southern Denmark, said in a release. “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."

"There has been much research into the role of the insulin pathway in breast cancer, but the exact mechanisms are still unknown,” Conference Chair, Professor Fatima Cardoso, said in the release. “This study shows clearly that a link between diabetes treatment and breast density, an important risk factor for the disease, has been made. I hope that these findings will lead to further research into the effect of cheap, easily-available drugs such as metformin, not just on breast density, but on breast cancer risk overall."