Besides high body mass index (BMI), individuals with increased belly fat may be at a greater risk of developing cancer, including of the breast and bowel, especially in older adults, researchers have warned.
Being overweight or obese is the single biggest preventable cause of cancer after smoking.
The findings revealed that for every 11 cm increase in the waistline, the risk of obesity related cancers such as breast, bowel, womb, oesophageal (food pipe), pancreatic, kidney, liver, upper stomach (gastric cardia), gallbladder, ovarian, thyroid, etc., escalates by 13 per cent.
Adding nearly eight cm to the hips increases the risk of developing bowel cancer by 15 per cent.
“Our findings show that both BMI and where body fat is carried on the body can be good indicators of obesity-related cancer risk. Specifically, fat carried around the waist may be important for certain cancers,” said lead author Heinz Freisling and scientist at the International Agency for Research on Cancer (IARC-WHO) in France.
Carrying excess body fat can change the levels of sex hormones, such as oestrogen and testosterone, cause levels of insulin to rise, and thus lead to inflammation, all of which are factors that have been associated with increased cancer risk, the researchers explained.
In the study, published in the British Journal of Cancer, the team showed that three different measurements of body size — BMI, waist circumference, and waist to hip ratio — all predicted similar obesity-related cancer risk in older adults.
“To better reflect the underlying biology at play, we think it’s important to study more than just BMI when looking at cancer risk. And our research adds further understanding to how people’s body shape could increase their risk,” Freisling added.
The researchers combined data from around 43,000 participants who had been followed for an average of 12 years and more than 1,600 people were diagnosed with an obesity-related cancer.