New-Onset Type 2 Diabetes Linked to Higher Cancer Risk

New research to be presented at this year’s European Congress on Obesity (ECO), taking place May 11-14 in Malaga, Spain, reveals that a new diagnosis of type 2 diabetes (T2D) is associated with an increased risk of developing certain obesity-related cancers—most notably liver, pancreatic, and bowel cancer—while showing no significant link to others such as endometrial or postmenopausal breast cancer.

This new study found increased risks for liver, pancreatic, and bowel cancers following a new diagnosis of type 2 diabetes—but not all obesity-related cancers show a link. | Image credit: abidika - stock.adobe.com

“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, body fat composition, or due to a simple difference in the number of cancers found in men and women within UK Biobank by chance,” wrote the researchers of the study.

An estimated 589 million people worldwide are currently living with diabetes, and alarmingly, more than 250 million of them remain undiagnosed, according to the 11th edition of the International Diabetes Federation’s (IDF’s) Diabetes Atlas.² Additionally, the IDF noted that nearly 1 in 9 adults globally now has diabetes. This widespread underdiagnosis carries serious health consequences, leaving millions at increased risk for severe complications and premature death.

To investigate the relationship between new-onset T2D and obesity-related cancers (ORCs), the researchers conducted a matched cohort study using data from the UK Biobank.¹ Participants with newly diagnosed non–insulin-dependent T2D were identified and matched in a 1:3 ratio with control participants based on body mass index (BMI), age, and sex.

The primary outcome was the incidence of ORCs, including liver, pancreatic, bowel, endometrial, postmenopausal breast, and others. To reduce bias, the analysis excluded individuals with prevalent diabetes and accounted for potential confounders such as smoking, alcohol consumption, and the increased likelihood of cancer diagnoses shortly after a diabetes diagnosis due to heightened medical surveillance.

Over a median follow-up of 5 years, the study identified 2431 new primary cancers among participants with newly diagnosed T2D and 5184 among matched controls. Analysis revealed that new-onset T2D was associated with a 48% increased risk of developing obesity-related cancers in men and a 24% increased risk in women, independent of BMI.

Notably, the risk varied by cancer type. New-onset T2D was linked to a 27% increased risk of bowel cancer in men and 34% in women, a 74% increased risk of pancreatic cancer in men and nearly double the risk in women, and a near-quadrupling of liver cancer risk in men and a nearly 5-fold increase in women.

However, no significant associations were found between T2D and certain cancers, including endometrial and postmenopausal breast cancer, suggesting that the diabetes-cancer link may be site specific and influenced by sex-related factors.

“Having accounted for key biases found in previous research in this field, and confounding (by adjusting for BMI, smoking, alcohol, and detection-time bias), our findings indicate that new-onset T2D is associated with some but not all site-specific obesity-related cancers,” wrote the researchers. “In turn, the pathways through which T2D may affect obesity-related cancer require further investigation.”

References

1. Study of UK biobank reveals link between new-onset type 2 diabetes and some but not all obesity-related cancers. European Association for the study of obesity. News release. Eurek Alert; March 22, 2025. Accessed April 23, 2025. https://www.eurekalert.org/news-releases/1077674

2. Steinzor P. More than 250 million individuals unaware they have diabetes. AJMC^®. April 7, 2025. Accessed April 23, 2025. https://www.ajmc.com/view/more-than-250-million-individuals-unaware-they-have-diabetes