Preventing diabetes means preventing cancer

Type 2 diabetes is increasing across the globe: according to the World Health Organization (WHO), 108 million people were affected by this serious metabolic disorder in 1980, but the figure had already risen to 422 million by 2014. There is a particularly strong increase in the number of people with diabetes in emerging economies. In Germany, around 500,000 people are diagnosed with diabetes for the first time every year.

During recent years, a large number of epidemiological studies have confirmed that people with diabetes have a considerably greater risk of developing cancer. In 2018, a meta-analysis by Australian researchers* showed that the cancer risk for men with diabetes is 19% higher than in the general population, and 27% higher for women with diabetes. A current publication** by scientists from the DKFZ and the National Center for Tumor Diseases (NCT) Heidelberg confirms this link for colorectal cancer, particularly for disease at a younger age.

Yet how can type 2 diabetes affect the development of cancer? Experts now assume that the risk of cancer is already higher even before type 2 diabetes is diagnosed: in many cases, diabetes itself is often preceded by a derailed metabolism known as metabolic syndrome. The syndrome is characterized by four main features: obesity, particularly around the waist; dysregulation of blood lipids; high blood pressure; and high blood sugar, often already associated with insulin resistance.

"Metabolic syndrome is thus also referred to as the deadly quartet," remarked Mathias Heikenwälder, metabolism expert at the DKFZ. "Excess fat around the waist is particularly dangerous in terms of developing cancer," he added, "because this fatty tissue releases messenger substances – adiponectins and cytokines – into the surrounding cells that trigger inflammatory reactions and reduce the effect of insulin. Some of these messenger substances also act as growth factors. They promote cell division in other cells and are thus conducive to tumor growth too." Moreover, the fat cells produce estrogens, which can stimulate cell growth in hormone-sensitive breast and uterine tissue.

If the metabolic syndrome exists over a period of many years, this may lead to type 2 diabetes; other common secondary diseases include arteriosclerosis, heart attack, stroke – and cancer.

However, the serious health problems caused by the metabolic syndrome can be averted; the development of disease can be halted by lifestyle changes. "Diet and exercise are the areas that those affected need to address," explained medical professional Susanne Weg-Remers, head of the Cancer Information Service at the DKFZ. That primarily means taking care to eat a balanced diet and maintain an energy balance. Regular exercise, if possible for 30 minutes a day, is equally important. Exercise increases energy expenditure and thus helps to reduce excess weight. However, Weg-Remers also knows how difficult most people find it to change long-standing unhealthy habits. "But it is worth it: If you take consistent action in time, you can considerably reduce your individual risk of developing cancer and other serious secondary diseases of the metabolic syndrome."

World Diabetes Day was launched by the International Diabetes Federation and WHO. It was first celebrated on November 14, 1991 and became an official United Nations Day in 2007. The date chosen for the day, November 14, was the birthday of Sir Frederick Banting, who discovered insulin with his colleague Charles Best in 1922.

* Toshiaki Ohkuma, Diabetology 2018, DOI: https://doi.org/10.1007/s00125-018-4664-5

** Uzair Ali Khan, Mahdi Fallah, Yu Tian, Kristina Sundquist, Jan Sundquist, Hermann Brenner, and Elham Kharazmi: Personal History of Diabetes as Important as Family History of Colorectal Cancer for Risk of Colorectal Cancer: A Nationwide Cohort Study
Am J Gastroenterol 2020, DOI: https://doi.org/10.14309/ajg.0000000000000669