- Cancer incidence was 12% higher in men and 22% higher in women with type 2 diabetes during 2010–2022 than in people without diabetes.
- The largest differences were seen for cancers already associated with obesity.
- This is registry research presented at a conference and does not show that diabetes itself caused the additional cancers.
Heart disease, kidney disease and nerve damage dominate conversations about the long-term complications of diabetes.
New Danish research suggests cancer deserves more attention too.
Researchers used nationwide health records covering virtually the entire adult population of Denmark between 1996 and 2022.
Over those 27 years, 75,540 first cancers were recorded among people with type 2 diabetes, compared with more than 635,000 among people without diabetes.
The researchers then looked at how cancer incidence differed over time.
During 2010 to 2022, overall cancer incidence was 12% higher among men with type 2 diabetes and 22% higher among women compared with people without diabetes.
The equivalent differences during 1996 to 2009 had been 9% for men and 15% for women.
The gap was particularly large for cancers associated at population level with obesity.
In the later period, these cancers occurred 45% more often in men with type 2 diabetes and 30% more often in women.
Colorectal cancer incidence was 17% higher in men with type 2 diabetes and 14% higher in women.
Postmenopausal breast cancer was 8% higher.
Lung cancer incidence was also higher, by 23% in men and 25% in women with type 2 diabetes.
But the pattern was not uniform.
Prostate cancer incidence was actually 19% lower among men with type 2 diabetes.
This complexity is important.
Diabetes does not have one simple relationship with “cancer” as a single disease.
Different cancers have different biological and behavioural risk factors.
There are plausible links between insulin resistance, higher circulating insulin, excess body fat, inflammation and some forms of cancer.
The existing diabetes and cancer evidence has pointed in this direction for years.
But this study was not designed to work out why the difference exists.
Researchers did not have sufficient information to separate the contribution of body weight, smoking, alcohol, exercise and other lifestyle factors.
That means it would be wrong to say type 2 diabetes itself caused the additional cancers.
The study has also been presented for the EASD annual meeting rather than published as a full peer-reviewed paper at this stage.
For people living with diabetes in the UK, there is no recommendation here for special cancer screening beyond NHS programmes.
The practical message is to take up routine screening when invited and continue working on the same modifiable risk factors that protect against several diseases at once.
That includes maintaining good blood glucose control, addressing excess weight through sustainable weight management, being physically active and not smoking.
Those behaviours also reduce heart disease risk, which remains one of the most important threats associated with diabetes.
The emerging message is therefore not that people with diabetes should fear cancer.
It is that long-term diabetes care increasingly needs to look beyond glucose and consider the whole pattern of future health risk.
