WEDNESDAY, March 2, 2016 (HealthDay News) -- Individuals with type 1 diabetes appear to have a higher risk for cancers of the stomach, liver, pancreas, endometrium, ovary, and kidneys, but a reduced risk for prostate and breast cancers, according to research published online Feb. 29 in Diabetologia.
Sarah Wild, Ph.D., professor of epidemiology at the University of Edinburgh in the United Kingdom, and colleagues collected data from national registries on 9,149 cancers among patients with type 1 diabetes from Australia, Denmark, Finland, Scotland, and Sweden. Looking at all cancers combined, Wild's team didn't find an increase in cancer risk for men with type 1 diabetes. However, women with type 1 diabetes had a 7 percent increased cancer risk. The lack of overall cancer risk among men with type 1 diabetes was mostly due to an apparent 44 percent decreased risk of prostate cancer, Wild said.
When data for sex-specific cancers -- such as prostate and breast cancers -- were removed from the analysis, an increased cancer risk was seen in both men and women with type 1 diabetes. That increased risk was 15 percent for men and 17 percent for women. Type 1 diabetes was linked to a 23 percent higher risk of stomach cancer for men and a 78 percent higher risk for women, the researchers found. For liver cancer, the risk for men with type 1 diabetes was doubled, while it was 55 percent higher for women. However, women with type 1 diabetes were 10 percent less likely to develop breast cancer.
During the first year after a diabetes diagnosis, the cancer risk was more than doubled for both men and women. The longer someone had type 1 diabetes, the lower the odds of cancer diagnosis, Wild told HealthDay. After about 20 years, the cancer risk dropped to that of the general population for men. For women, it took only five years for the cancer risk to drop to almost normal. "This pattern of cancer risk [seen in the study] is similar to that seen for people with type 2 diabetes and people who are overweight," Wild said. "This suggests that insulin treatment for type 1 diabetes does not itself increase risk of cancer."
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