国际英语新闻:Excess weight may increase risk of 8 more cancers: study

WASHINGTON, Aug. 24 (Xinhua) -- People who are overweight and obese are at a heightened risk for developing eight additional types of cancer, an international team of researchers said Wednesday.

However, the team was quick to add that limiting weight gain could help to reduce the risk of these cancers, namely stomach, liver, gall bladder, pancreas, ovary, meningioma, thyroid cancer and multiple myeloma.

The findings, published in The New England Journal of Medicine, are based on a review of more than 1,000 studies of excess weight and cancer risk analyzed by the World Health Organization's International Agency for Cancer on Research (IARC), based in France.

In 2002, the same group of cancer researchers found sufficient evidence linking excess weight to higher risks of cancers of the colon, esophagus, kidney, breast and uterus.

"The burden of cancer due to being overweight or obese is more extensive than what has been assumed," said cancer prevention expert Graham Colditz at the Washington University School of Medicine in St. Louis, who chaired the IARC Working Group.

"Many of the newly identified cancers linked to excess weight haven't been on people's radar screens as having a weight component."

The cancer risks associated with excess weight were similar for men and women and were consistent across geographic regions -- North America, Europe, Asia and the Middle East, said the researchers.

There are many reasons why being overweight or obese can increase cancer risk, they noted. Excess fat leads to an overproduction of estrogen, testosterone and insulin, and promotes inflammation, all of which can drive cancer growth.

The findings could have a significant bearing on the global population. Worldwide, an estimated 640 million adults and 110 million children are obese.

"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," he added. "Rather than getting discouraged and giving up, those struggling to take off weight could instead focus on avoiding more weight gain."