A new international study, published in the Lancet Oncology, revealed that 5.4% of cancer cases in women and 1.9% of cases in men are linked to a high BMI. The qualitative analysis of cancer in men include the esophagus, bowel, kidneys, pancreas and in women the gallbladder, ovaries, uterus and postmenopausal breast cancer.
Obesity is associated with surplus body fat, interfering with various hormone cycles and with glucose and fat metabolism. Abdominal fat is associated with metabolic syndrome and an increased level of inflammation throughout the body. A BMI (Body Mass Index) of between 18.5 and 24.9 is considered normal but, a BMI of more than 25, is considered to be overweight.
“People with a BMI of 30 and above are predominantly affected”, said Alexandra Kautzky-Willer, Vice Principal of the University Department of Internal Medicine III of MedUni Vienna and member of the Comprehensive Cancer Center (CCC) Vienna. “An increase in BMI by only a factor of 1, for example from 29 to 30, increases your cancer risk by between 3% and 10% for the said types of cancer. Particularly abdominal fat, also known as visceral fat, has a negative impact on health, since it increases your cancer risk and encourages the development of metabolic disorders such as diabetes, or cardiovascular disease.”
The cancer risk is increased as fatty tissue is hormonally active, produces adipose tissue hormones and changes the balance of sex hormones. This encourages the development and growth of hormone-related tumous, such as various forms of breast cancer or endometrial cancer. Tumor growth is encouraged by the detrimental shift in the balance of sex hormones and adipose tissue hormones. It also leads to an increase in insulin resistance, which the body responds to in turn by increasing insulin production.
“The problem with that is that insulin not only regulates the metabolism but can also act as a growth-stimulating hormone and encourage cell division and hence tumor growth, said Kautzky-Willer. “We can therefore see a close relationship between diabetes and certain types of cancer, in particular liver and pancreatic cancer”. ” Another aspect is that chronic inflammatory processes can occur in the region of the abdominal fat and these also favor the development of cancer”. “The positive thing is that you can do something about this risk by losing weight or keeping an eye on your weight from the outset. Many types of cancer could be easily avoided in this way; a Mediterranean diet and exercise also help.”
Melina Arnold, Nirmala Pandeya, Graham Byrnes, Andrew G Renehan, Gretchen A Stevens, Majid Ezzati, Jacques Ferlay, J Jaime Miranda, Isabelle Romieu, Rajesh Dikshit, David Forman, Isabelle Soerjomataram. Global burden of cancer attributable to high body-mass index in 2012: a population-based study. Lancet Oncology, May 2015 DOI: 10.1016/S1470-2045(14)71123-4