Eight additional types of cancer are now linked to the obesity epidemic in this country: gall bladder, liver, meningioma, multiple myeloma, ovary, pancreas, stomach and thyroid cancers.
The findings are based on an analysis of more than 1,000 studies of excess weight and cancer risk analyzed by the World Health Organization’s France-based International Agency for Cancer on Research.
“The burden of cancer due to being overweight or obese is more extensive than what has been assumed,” said Graham Colditz, a cancer prevention expert at the School of Medicine at Washington University in St. Louis. “Many of the newly identified cancers linked to excess weight haven’t been on people’s radar screens as having a weight component.”
It is estimated that one-third of adults and children in the United States are too heavy, and researchers say limiting weight gain could help reduce the risk of these cancers.
This same group of cancer researchers found sufficient evidence linking excess weight to higher risks of cancers of the colon, esophagus, kidney, breast and uterus in an different study from last decade.
“Lifestyle factors such as eating a healthy diet, maintaining a healthy weight and exercising, in addition to not smoking, can have a significant impact on reducing cancer risk,” Colditz said. “Public health efforts to combat cancer should focus on these things that people have some control over. But losing weight is hard for many people. Rather than getting discouraged and giving up, those struggling to take off weight could instead focus on avoiding more weight gain.”
The reasons why being overweight or obese can increase cancer risk are many, according to the researchers. Excess fat leads to an overproduction of estrogen, testosterone and insulin, and promotes inflammation, all of which can drive cancer growth.
“Significant numbers of the U.S. and the world’s population are overweight,” Colditz said. “This is another wake-up call. It’s time to take our health and our diets seriously.”
