A new meta-analysis has found that people with diabetes appear to have a higher risk of developing cancer than those without diabetes, and the risk is greater in women than men.
Although previous studies have found a link between diabetes and cancer risk, it wasn’t clear until now whether gender also played a role. In the study, which was published today in the journal, Diabetologia, the researchers analyzed earlier studies that reported a link between cancer and diabetes.
After removing studies that looked at only a single gender and studies that hadn’t adjusted for age, the researchers ended up analyzing data from more than 19 million individuals with either type 1 or type 2 diabetes across more than 100 studies and data sets. Researchers did not adjust for other factors that could be associated with diabetes and cancer in women, such as pregnancy, menopause and hormone-replacement therapy.
The researchers found that women with diabetes had a 27 percent higher risk of cancer compared with women without diabetes, while men with diabetes had a 19 percent higher risk of cancer compared with men without diabetes. Comparing men and women, the researchers found that women with diabetes had a 6 percent higher risk of cancer than men with diabetes.
When scientists looked at specific types of cancer, they found that woman with diabetes again had a higher risk for most cancers than men with diabetes. For example, compared with men with diabetes, women with diabetes had an 11 percent higher risk of developing kidney cancer, a 13 percent higher risk of oral cancer, a 14 percent higher risk of stomach cancer and 15 percent higher risk of leukemia. Men with diabetes had a 12 percent higher risk of developing liver cancer compared with women with diabetes, however.
While it remains unclear why women are more at risk, there are several hypotheses. Women often spend longer duration than men in the prediabetic stage where glucose levels are high, women are often undertreated or not getting the same level of treatment as men, and a 2015 study showed that women were less likely than men to take the medication needed to lower blood glucose levels.
In all three scenarios, women with diabetes are more likely than men to have uncontrolled blood sugar levels for longer periods of time. Because of this, women with diabetes may be at greater risk of developing cancer than men with diabetes.