Obesity found to trigger 8 MORE types of cancer
The greater a person's BMI the higher their risk of developing stomach, liver, gall bladder, pancreas, ovary, and thyroid cancer, as well as brain tumour and blood cancer
Obese or overweight people are at greater risk of eight more types of cancer, scientists have warned.
Carrying excess weight is known to be a high risk factor for a number of forms of the disease, including breast, kidney and bowel cancer.
But, experts have now identified eight additional tumours that are linked to being fat.
The higher a person's body mass index, the greater their risk of developing stomach, liver, gall bladder, pancreas, ovary, meningioma (a type of brain tumour), thyroid cancer, as well as multiple myeloma, a cancer of the blood.
Cancer prevention expert Dr Graham Colditz at the Washington University School of Medicine in St. Louis, said: "The burden of cancer due to being overweight or obese is more extensive than what has been assumed.
"Many of the newly identified cancers linked to excess weight haven't been on people's radar screens as having a weight component."
Limiting weight gain over the decades, could help reduce the risk of these cancers, the researchers said.
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Their 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 anaylsed by the World Health Organisation's International Agency for Cancer on Research (IARC).
The findings could have a significant bearing on the global population.
Across the world, experts estimate 640 million adults and 110 million children are obese, including one in three adults and children in the US.
In 2002, the same group of scientists found being overweight increases the risk of cancers of the colon, oesphagus, kidney, breast and uterus.
There are a number of reasons why being overweight or obese can increase the risk of cancer, the researchers said.
Being overweight leads to the body overproducing the hormones oestrogen, testosterone and insulin, and obesity also promotes inflammation - all of which can drive cancer growth.
Dr Colditz said: "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 the cancer risk.
"Public health efforts to combat cancer should focus on these things that people have some control over."
Dr Colditz recognised losing weight can be 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."
The researchers noted the cancer risks linked to excess weight were similar for men and women.
And, furthermore, where the data was available, the risks were consistent across geographic regions, including North America, Europe, Asia and the Middle East.
Dr Colditz concluded: "Significant numbers of people in the US and the world's population are overweight.
"This is another wake-up call. It's time to take our health and our diets seriously."