Cancer incidence is increasingly outpacing that of the wider population among people with type 2 diabetes, driven largely by obesity-related cancers, Danish data suggest.
People with type 2 diabetes are facing a growing excess burden of cancer, with the gap in incidence compared with people without diabetes widening over recent decades, according to a nationwide Danish study.
Researchers found overall cancer incidence was 12% higher among men with type 2 diabetes and 22% higher among women with the condition in 2010-22, compared with people without diabetes.
That gap had widened from 9% for men and 15% for women in 1996-2009.
The findings, to be presented at the European Association for the Study of Diabetes annual meeting in Milan next week, were based on nationwide health registry data covering Denmark’s adult population from 1996 to 2022.
Researchers identified 75,540 first cancers among people with type 2 diabetes during 27 years of follow-up, compared with 635,323 among people without diabetes.
The difference was particularly pronounced for cancers associated with obesity. In 2010-22, incidence of obesity-related cancers was 45% higher among men with type 2 diabetes and 30% higher among women compared with those without diabetes.
In 1996-2009, the corresponding excesses were 34% and 23%.
Study lead Dr Tinne Laurberg, of Steno Diabetes Center Aarhus and Aarhus University Hospital, said the findings highlighted the growing importance of cancer prevention and early detection in diabetes care.
“Our findings underline the growing cancer burden among people with T2D and highlight the need to prioritise cancer prevention and early detection as part of long-term diabetes care,” Dr Laurberg said.
“This is especially important for common obesity-related cancers, such as colorectal and postmenopausal breast cancer, for which screening program already exist in many countries.
“We must ensure that people with T2D benefit fully from these established programs by encouraging greater participation.”
The pattern varied considerably according to cancer type and sex.
Postmenopausal breast cancer incidence was 8% higher among women with type 2 diabetes in 2010-22, while colorectal cancer incidence was 17% higher among men and 14% higher among women with diabetes.
Lung cancer incidence was also elevated, by 23% in men and 25% in women with type 2 diabetes during the most recent study period.
The changing pattern for lung cancer among women was particularly striking. During 1996-2009, incidence was 12% lower among women with type 2 diabetes than among those without diabetes, but by 2010-22 it was 25% higher.
Prostate cancer bucked the trend, with incidence 19% lower among men with type 2 diabetes compared with men without diabetes in 2010-22.
The researchers said prolonged exposure to hyperglycaemia and elevated insulin levels, insulin resistance, and chronic inflammation were potential biological contributors to cancer development in people with type 2 diabetes.
Cancer has also emerged as an increasingly important cause of mortality as outcomes from other diabetes complications have improved. Over the past decade, it has become the leading cause of death among people with type 2 diabetes in Denmark and other high-income countries, according to the researchers.
Dr Laurberg said cardiovascular and kidney disease prevention remained central to diabetes care, but improvements in outcomes for these complications meant cancer may warrant greater attention.
“Our results underline the importance of considering cancer prevention and early detection alongside other established aspects of diabetes care, particularly for common cancers such as colorectal, lung, and breast cancer,” she said.
The researchers cautioned that the observational study was designed to describe differences in cancer incidence rather than establish that type 2 diabetes caused the excess risk.
Related
The analysis also did not assess factors that could contribute to the differences or their change over time, including body weight, smoking, alcohol consumption, and physical activity.
The researchers said that categorising cancers as obesity-related reflected established population-level associations with obesity and did not demonstrate that obesity explained the higher cancer incidence seen among people with type 2 diabetes.
The findings come as the latest Australian Institute of Health and Welfare data released in May this year showed about 1.3 million Australians were living with diabetes in 2022-24, while type 2 diabetes accounted for an estimated 128,000 years of healthy life lost in 2024, or 2.2% of Australia’s total disease burden.
AIHW data also points to an overlap between diabetes and several cancers. In 2024, the institute’s Australian Burden of Disease Study showed lung cancer was the underlying cause of 3.3% of deaths in which diabetes was recorded as an associated cause, while pancreatic and colorectal cancers accounted for 2.3% and 2.2%, respectively.
The study also identified diabetes as a risk factor for bladder, bowel, breast, liver, lung, ovarian, and pancreatic cancers.
