Blood sugar control is important for reducing cancer risk in obesity and type 2 diabetes. Significant weight loss appears to afford protection against cancer, but good blood sugar control reduces cancer cases radically, a study by the University of Gothenburg shows.
The study was published in the journal Diabetes Care and used data from the “SOS” (Swedish Obese Subjects) intervention trial. It was led and coordinated by the University of Gothenburg to research the correlation between good blood sugar control and reduced cancer risk.
Obesity is a risk factor for both type 2 diabetes and several types of cancer. However, intentional weight loss through bariatric surgery, for example, can often ameliorate diabetes, and many patients achieve normal blood sugar control. However, there have been relatively few studies on the association between weight loss, risk of cancer and glucose control in patients with both obesity and type 2 diabetes.
The risk of uncontrolled blood sugar
The researchers studied a group of 393 people with type 2 diabetes who underwent bariatric surgery and compared them with a control group of 308 people with the same clinical characteristics; however, they had not had the weight loss surgery. The groups were comparable regarding gender composition, blood sugar, and smoking.
In the surgery group, 68 individuals (approximately 17%) developed cancer, corresponding with a significant weight loss. The emerging cancer cases in the control group amounted to 74 (24%) and the individuals retained severe obesity. The median follow-up period was 21 years. Overall, the risk of getting cancer was 37% lower in the group that underwent obesity surgery.
The largest difference was observed when cancer risk was analysed in the patients who achieved normal glucose control and had no relapse of diabetes over a ten-year period. Amongst these patients, the incidence of cancer was only 12 out of 102 (12%), against 75 out of 335 (22%) in the group whose diabetes had recurred in the same period. The results show a 60% reduction in cancer risk in the group where normal glucose control was maintained over ten years.
Cancer prevention
“What we see is that, among patients with type 2 diabetes, many cancer cases are preventable. These results are an important contribution that enhances our understanding of the connection between glucose control and cancer prevention,” said Kajsa Sjöholm, Associate Professor of Molecular Medicine at Sahlgrenska Academy, University of Gothenburg, and the study’s first author.
Magdalena Taube, Associate Professor of Molecular Medicine at Sahlgrenska Academy, the University of Gothenburg and the senior author of the study, said: “The global epidemic of both obesity and diabetes leads to an increased risk of cancer, as well as an increased risk of premature death. It has been estimated that, over the next 10 to 15 years, obesity may cause more cancer cases than smoking in several countries. This is a clear illustration of how serious the condition is.
“Strategies are needed to prevent this development, and our results can provide vital guidance for prevention of cancer in patients with obesity and type 2 diabetes.”
