Bulging tummy raises colon cancer risk

Extra flab around the belly raises the risk of developing colon cancer in women. Studies of colon cancer risk in males have reported strong positive associations with obesity, particularly with extra fat in the abdomen, also known as central adiposity. However, researchers from the University of Melbourne, Australia, found that this association has been weaker and less consistent for women. The researchers examined the association between body size and shape and the risk of colon cancer in 24,000 women followed for 10 years. Direct body measurements were taken and bioelectrical impedance analysis was used to estimate fat mass and fat-free mass. Central adiposity was estimated by waist circumference and waist-to-hip ratio (WHR). A total of 212 women were diagnosed with colon cancer during follow-up. The average age at diagnosis was 66 years. It was found that the risk of colon cancer increased as central adiposity rose. A fat-related hormone called leptin, which has been associated with colon cancer in men, might be another link between obesity and colon cancer. Leptin has also been shown to stimulate the growth of colon cells in the lab. There are a number of possible mechanisms that may explain the association between obesity and colon cancer. High levels of physical activity have consistently been shown to reduce the risk of colon cancer and may be linked to the mechanism whereby obesity predisposes to colon cancer.