"In addition, in men, there is now evidence that increasing waist circumference in middle age is associated with increased bowel cancer risk," said Mathers. CRC risk was increased by nearly 60 per cent in men who gained at least 10 cm in waist circumference over 10 years.
"This increased cancer risk may be due to persistent inflammation in people with obesity," Mathers said. Mathers studied patients with Lynch Syndrome (LS) who have a higher than normal risk of CRC because of an inherited defect in one of the genes responsible for repairing DNA.
Mathers presented new data showing that, in people with Lynch Syndrome, CRC risk increases with higher body weight and for those who are obese the risk of CRC is doubled. The increase in CRC risk with higher body weight in people with Lynch Syndrome was about twice as great as that seen in the general population. "There is now compelling evidence that improved lifestyle, particularly better dietary choices and being more physically active, can help to prevent obesity and this will lower bowel cancer risk," Mathers said.
"In addition, for those people who are already too heavy, losing weight may reduce their CRC risk but this is an area which requires further study," he said. In his studies with Lynch Syndrome patients, Mathers observed that aspirin lowered the excess CRC risk seen in patients with obesity, perhaps through its anti-inflammatory effects.