People with type 1 diabetes have a higher risk of developing some types of cancer, according to a study which combined data from five countries: Australia, Denmark, Finland, Scotland, and Sweden.
The study, conducted by senior statistician Bendix Carstensen at the Steno Diabetes Center in Denmark; Prof. Sarah Wild and Stephanie Read at the University of Edinburgh in Scotland; and other members of the European Association for the Study of Diabetes; was published in the journal Diabetologia and titled, “Cancer incidence in persons with type 1 diabetes: a five-country study of 9,000 cancers in type 1 diabetic individuals.”
In previous studies, those with type 2 diabetes were shown to have 20 to 25 percent higher risk of cancer compared to those without diabetes. Now, scientists decided to explore cancer’s incidence in type 1 diabetes.
The research team analyzed more than 9,000 cases of cancer diagnosed in type 1 diabetes patients compared to the estimated cancer incidence in the general population.
Researchers found that type 1 diabetes patients have a higher risk of developing cancer in the pancreas (53 percent in men, 25 percent in women); stomach (23 percent in men, 78 percent in women); liver (twofold among men, 55 percent in women); kidney (30 percent in men, 47 percent in women); and endometrium (42 percent in women); compared to the general population.
However, the study indicates a reduced risk for type 1 diabetics to develop ovary, prostate, and breast cancer.
Men with type 1 diabetes did not show an increased overall cancer risk. In fact, man evidenced 44 percent less incidence of prostate cancer, one of the most common non-skin cancer in men.
However, women with type 1 diabetes showed a 7 percent higher risk of developing cancer. But breast cancer appeared to be 10 percent less likely to appear in women with type 1 diabetes. The reason behind this is still unclear.
When removing data for sex-specific cancer types (prostate, testis, breast, cervix, endometrium, and ovary), scientists verified that cancer risk was increased 15 percent in men and 17 percent in women with type 1 diabetes.
Higher cancer incidences were verified after type 1 diabetes was diagnosed. Researchers suggested that this might be due to the increased medical attention that patients obtain when diagnosed with diabetes, which facilitates the detection of pre-existing cancer shortly after the diabetes diagnosis.
Another relevant result of the study is that it does not support the hypothesis that insulin treatment might be a major risk factor for cancer development, since type 1 diabetes patients showed a smaller increase in cancer incidence when compared to previous type 2 diabetes reports.
The authors hypothesized that an overall increased cancer risk among diabetic patients (both type 1 and 2) might be due to a common mechanism related to high blood sugar levels, which might occur in both types of diabetes.
“Our findings do not support changes in policy for cancer screening for persons with type 1 diabetes,” the research team concluded in a news release. “Recommendations for lifestyle approaches to reducing cancer risk such as avoiding smoking, weight management, and physical activity apply to persons with type 1 diabetes as for the general population.”