January 25, 2026, 4:39 am | Read time: 8 minutes

Why is diabetes referred to as a widespread disease? Because of the following figures: There are currently around 11 million people living with diabetes in Germany. This includes 8.7 million with diagnosed type 2 diabetes and 372,000 with type 1 diabetes. The estimated number of unreported cases is around two million people who are still unaware of their condition. Every year, more than half a million adults are newly diagnosed with diabetes, which corresponds to around 1600 new cases per day^.1 This indicates that there are approximately 13 million diabetics in Germany, many of whom are undergoing treatment for their condition or should be, and who also face a high risk for additional serious health issues. Included among these are various forms of cancer. The aforementioned study has identified which types and the extent to which a diabetes diagnosis elevates the risk.

Obesity, Diabetes, and Risk of Cancer

Obesity caused by a poor diet is the biggestrisk factor for the development of type 2 diabetes. Around 80 percent of diabetics are overweight^.2 It is also scientifically proven that various cancers are linked to being overweight or obese. This includes kidney cancer, bowel cancer, liver cancer, oesophageal cancer, pancreatic cancer, and—in women—breast cancer and ovarian cancer^.3,4

As both diabetes and various types of cancer are linked to obesity, researchers from the UK wanted to know to what extent there was also a link between a new diabetes diagnosis and cancer. To do this, they not only looked at the overall risk of cancer, but also the risk of individual cancers associated with obesity.

Background to the Study

A research team from Manchester University conducted the study. The study was scheduled to be presented at the European Congress on Obesity (ECO 2025) in May in Spain. The study, of which only a press release from the “European Association for the study of Obesity” is currently available, has not yet been independently peer-reviewed, which is why its findings should still be taken with a grain of salt^.5 Nevertheless, we believe it is important to share the significant figures resulting from the analysis.

Also interesting: Common Deficiency Symptoms Associated with Diabetes

How the Study Went

The British researchers conducted a cohort study using data from the UK Biobank. This design makes it possible to determine possible links between an exposure (e.g., diabetes) and a characteristic (e.g., breast cancer).

Data from 23,750 people with newly diagnosed type 2 diabetes mellitus (T2DM) were included. For each of these individuals, three comparison subjects (a total of 71,123 subjects formed the control group) were selected who did not have diabetes but were matched in age, gender, and body mass index (BMI). The focus was on the occurrence of 14 defined obesity-associated cancers. The cancer risks were analyzed separately for men and women. Statistical models were used to take into account possible influencing factors. These factors included alcohol consumption, smoking, and increased medical attention immediately after the diabetes diagnosis.

The average follow-up duration was five years. During this period, it was documented whether a new cancer occurred in the participants. The aim was to determine whether people with newly diagnosed type 2 diabetes were more likely to develop certain types of cancer than comparable people without diabetes.

The 14 Types of Cancer Considered:

• Liver cancer
• Pancreatic cancer
• colorectal cancer
• postmenopausal breast cancer
• cancer of the uterus
• kidney cancer
• esophageal cancer
• stomach cancer
• Multiple myeloma (tumors of bone and bone marrow)
• Gallbladder cancer
• Thyroid cancer
• Meningioma (tumors originating from the meninges)
• Ovarian cancer

Diabetes in Men Associated With 48 Percent Increased Risk of Cancer

During the follow-up, 2431 new cancer cases were detected in the group with type 2 diabetes. This compares to 5184 cancer cases in the control subjects. The data indicated that newly diagnosed type 2 diabetes was linked to a 48 percent higher risk of obesity-associated cancers in men and a 24 percent higher risk in women, independent of BMI.

Risk Not the Same for All Cancers

However, not all types of cancer were affected. For example, no significant correlation was found for post-menopausal breast cancer and uterine cancer.

On the other hand, the following types of cancer showed a significantly increased risk:

• Liver cancer: risk increased almost fourfold in men, almost fivefold in women.
• Pancreatic cancer: risk increased by 74 percent in men, almost doubled in women.
• Colorectal cancer: risk increased by 27 percent in men, 34 percent in women.

“After accounting for key biases identified in previous research in this area and confounding factors (by adjusting for BMI, smoking, alcohol, and time of detection), our results suggest that new-onset T2DM is associated with some, but not all, site-specific obesity-related cancers. The pathways by which T2DM may influence obesity-related cancers require further investigation,” the study authors assess the results, according to the press release.

Significance of the Study Results

The detailed findings of the current study could have great significance for medical practice and prevention. This is because they show that a new diagnosis of type 2 diabetes not only signals a metabolic disease, but also represents a warning sign for possible cancers at a later stage. The risk of pancreatic, liver, and bowel cancer appears to increase significantly with the onset of diabetes, regardless of body weight.

For people with type 2 diabetes, these findings could help to adapt individual prevention and early detection strategies, particularly for the types of cancer mentioned, on which diabetes appears to have a particularly strong influence, according to the current study.

From a scientific point of view, the results underline the need for further research into the biological mechanisms behind this connection. In particular, the influence of hyperinsulinemia—i.e., permanently elevated insulin levels—is considered a promising explanation. Insulin can promote cell growth and cell division and thus possibly increase the risk of cancer. Chronic inflammation and elevated blood sugar (hyperglycemia) are also being discussed as factors. Whether and to what extent these effects manifest themselves differently in men and women remains an open question that future research must clarify. This is also emphasized by the study authors themselves: “At this stage, we are not sure 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 whether it is simply a random difference in the number of cancers found in men and women in the UK Biobank.”

More on the topic

Study Overweight teenagers have an increased risk for 17 types of cancer in adulthood

Studies The Diet That Can Provenly Reduce Cancer Risk

Classification of the Study Findings

The major strength of the study is its design. It addresses many previous weaknesses of previous studies, such as the separate recording of newly diagnosed diabetes, the careful selection of control subjects, and the adjustment for important confounding factors such as BMI, smoking, or alcohol consumption. The use of the UK Biobank data provides a solid basis, as it is a large and well-documented cohort.

Nevertheless, there are limitations. The average follow-up time of five years is relatively short, considering that many cancers have a long development time. It remains unclear how the risks develop over longer periods of time. In addition, the data is based on the UK population, which limits its applicability to other countries and ethnicities.

Earlier Study Already Showed Link Between Diabetes and Bowel Cancer

A study published in 2023 had already looked specifically at a possible increase in the risk of bowel cancer due to diabetes. It analyzed data sets from around 86,000 subjects from the Southern Community Cohort Study (SCCS), which investigates the relationship between cancer and other common diseases^.6

The result: diabetes increased the risk of colorectal cancer by 47 percent. People with a new diabetes diagnosis and those who did not have regular screening tests, such as a colonoscopy, were particularly at risk.

However, given that 66 percent of the subjects analyzed were African-American and 53 percent were of low income, the applicability of the findings to other diabetic populations is uncertain.

However, the current study from the UK can now generally confirm that there is a strong association between diabetes and the risk of developing various types of cancer. In the case of bowel cancer, it can also be confirmed that diabetes significantly increases the risk of developing cancer.

The German original of this article was published in March 2025.