A new diagnosis of type 2 diabetes (T2D) has been linked to an increased risk of developing certain obesity-related cancers, according to recent research.
While earlier studies have identified associations between type 2 diabetes and a heightened risk of several obesity-related cancers, questions have remained about whether these links are truly causal. Factors such as obesity—a common risk factor for both conditions—as well as potential biases like immortal time bias (stemming from the combination of pre-existing and new cases of T2D) and time detection bias (where two common conditions are diagnosed concurrently) have clouded the findings.
In this latest study, set to be presented at the European Congress on Obesity (ECO 2025) in Malaga, Spain, researchers aimed to overcome these methodological limitations. They conducted a matched cohort control study using data from the UK Biobank, comparing individuals newly diagnosed with T2D (defined by the date of first reported non-insulin-dependent diabetes) to unexposed individuals matched based on body mass index (BMI), age, and sex.
The study involved 23,750 participants with newly diagnosed T2D and 71,123 matched controls. Over a median follow-up period of five years, 2,431 new primary cancers were reported among T2D participants, compared to 5,184 cases among the control group.
The analysis revealed that new-onset T2D was associated with a 48 per cent increased risk of obesity-related cancers in men and a 24 per cent increased risk in women—an effect independent of BMI. However, the study found no association between T2D and certain site-specific cancers, such as endometrial cancer and post-menopausal breast cancer in women.
Positive associations were observed for specific cancers. New-onset T2D increased the risk of bowel cancer by 27 per cent in men and 34 per cent in women. The risk of pancreatic cancer rose by 74 per cent in men and nearly doubled in women. For liver cancer, new-onset T2D was linked to a near quadrupling of risk in men and a nearly five-fold increase in women.
“At this stage, we are unsure whether these differences in men and women are due to a sex-dependent biological pathway—such as hormone levels, insulin sensitivity, or body fat composition—or if they are simply the result of variations in the number of cancers found in men and women within the UK Biobank by chance,” the study authors noted.
– IANS