Researchers involved in the study , reporting at the San Antonio Breast Cancer Symposium, also examined overall cancer incidence and found that use of one diabetes drug was associated a lower cancer rate, while another was found to be associated with a heightened risk. The study examined health care data from a region of 1.5 million people living in Southwestern Sweden.
Professor at Lund University and lead author, Håkan Olsson, M.D., claims, “We are looking at everybody, and we found that diabetes in adult women and obesity in women aged 60 and older significantly increased breast cancer risk. This is useful information for women who want to know their risk and who can take steps to lower it.”
Olsson and associates examined health records of 2,724 patients up to 10 years before they developed cancer and 20,542 patients who never developed the disease. They discovered that for women over aged 60, obesity increased risk of developing breast cancer by 55 percent.
Olsson adds, “At the most, 15 of 100 obese women would get breast cancer compared with slightly less than 10 out of 100 in the general population. For women with diabetes, there was a 37 percent greater risk of developing breast cancer if they had their diabetes diagnosed up to four years before the cancer was diagnosed.
Women with unusually low levels of blood lipids (mainly cholesterol) had a 25 percent increased risk for developing breast cancer, while high levels of blood lipids appeared to be associated with a reduced risk for breast cancer. The scientific cause behind these effects is unclear, and the finding needs to be duplicated in a different population-based study, Olsson claimed.
The researchers also examined the national drug prescription registry to examine the link between cancer risk and the use of two diabetes drugs, glargine and metformin. The investigators discovered that glargine use, which had previously been associated with increased cancer development, nearly doubled the risk for developing any form of cancer. Metformin, on the other hand, was linked to an 8 percent reduced risk of developing cancer in patients with diabetes.
According to Olsson, more research is necessary to clearly understand the specific cancers facing an increased risk. The number of patients in the study who developed breast cancer as a result of using these medications was too small a sample to make any direct connection to breast cancer risk.