Cleveland Clinic researchers analyzed data from more than 25,600 women and men with type 2 diabetes to compare how two groups of widely used diabetes drugs affected cancer risk.
The drugs included "insulin sensitizers," which lower blood sugar and insulin levels in the body by increasing the muscle, fat and liver's response to insulin. The other drugs analyzed were "insulin secretagogues," which lower blood sugar by stimulating beta cells in the pancreas to make more insulin.
The use of insulin sensitizers in women was associated with a 21 percent decreased cancer risk compared to insulin secretagogues, the investigators found. Furthermore, the use of a specific insulin sensitizer called thiazolidinedione was associated with a 32 percent decreased cancer risk in women compared to sulphonylurea, an insulin secretagogue.
However, there were no significant differences between men who used insulin sensitizers or secretagogues, according to the study published online Dec. 5 in the journal Diabetes, Obesity and Metabolism.
"What this study shows us is that using insulin secretagogues to increase insulin production correlates with an increased cancer risk in women with type 2 diabetes," study leader Dr. Sangeeta Kashyap, an endocrinologist and associate professor of medicine at Cleveland Clinic's Endocrinology and Metabolism Institute, said in a clinic news release.
"By contrast, insulin sensitizers cut insulin levels and can decrease cancer growth. So, clearly, when prescribing anti-diabetic medications, it's important to consider the impact a drug has on fueling cancer growth," Kashyap added.
While the study found an association between specific types of diabetes drugs and higher or lower cancer risk in women, it did not establish a cause-and-effect relationship.
People with type 2 diabetes have higher rates of cancer diagnosis and recurrence than people in the general population, according to background information in the news release.
The American Diabetes Association has more about diabetes and cancer.