Women with Type 1 Diabetes Have Elevated Risk of Some Cancers

MedicalResearch.com Interview with:

Bendix Carstensen

Bendix Carstensen

Bendix Carstensen
Department of Clinical Epidemiology Steno Diabetes Center

Medical Research: What is the background for this study? What are the main findings?

Response: It has long been known that all diabetes patients have elevated risk of cancer (10-15%). Patients on insulin slightly more (20-25%). Type 1 patients is only a small fraction (10%) of all diabetes patients, but they ALL take insulin. If insulin has a role in cancer occurrence it would be expected to be particularly pronounced in type 1 patients, and increasing by duration.

But it is not, the risk of cancer is 15% elevated (if we disregard prostate, breast and other cancers only occurring in one of the sexes), and there is no increase in the excess risk by duration of insulin use. Breast cancer risk is 10% lower and prostate cancer risk some 40% lower. Overall there is very little increased cancer risk – 1% for men 7% for women.

Medical Research: What should clinicians and patients take away from your report?

Response: The cancer risk among type 1 diabetes patients has the same pattern as among type 2 patients, but the excess is less. The overall excess cancer risk is not so large that special recommendations for type 1 diabetes patients in relating to cancer prevention are required.

Medical Research: What recommendations do you have for future research as a result of this study?

Response: The follow-up of the persons in this study is in relatively young ages for cancer occurrence, and further monitoring of the type 1 patients would be desirable as information in older ages becomes available over the next decades. Also the survival after diagnosis of cancer in type 1 patients that do get cancer will be of interest. 

Medical Research: Is there anything else you would like to add?

Response: The study has been possible because the participating countries (Australia, Denmark, Finland, Scotland & Sweden) maintain registers of diabetes patients and cancer patients that can be linked. This way the information from persons with the diseases (diabetes and/or cancer) are used in research to inform the general public on the joint occurrence of the diseases, and – in this case – reassure type 1 diabetes patients that the excess cancer occurrence is quite moderate.


Carstensen B, et al “Cancer incidence in persons with type 1 diabetes: A five-country study of 9,000 cancers in type 1 diabetic individuals” Diabetologia 2016; DOI: 10.1007/s00125-016-3884-9.

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Bendix Carstensen (2016). Women with Type 1 Diabetes Have Elevated Risk of Some Cancer 

Last Updated on March 1, 2016 by Marie Benz MD FAAD