Meanwhile, the report also found that an estimated 4.5 million deaths in 2013 were related to overweight and obesity, a number that may increase as more cancers are found to be related to the condition.
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These cancers include stomach, liver, gall bladder, pancreas, ovary, thyroid, meningioma – a type of brain tumour – and blood cancer multiple myeloma. The higher the BMI, the greater the likelihood a person had of developing cancer.
Opposing the previous views of doctors that cancer was mainly caused by genetics and a stroke of bad luck, certain experts now emphasize the importance of a healthy lifestyle.
There was also some evidence suggesting a link between obesity and male breast cancer, diffuse large B-cell lymphoma and the most common form of non-Hodgkin’s lymphoma, according to the review.
Dr. Clifford Hudis, chief executive officer of the American Society of Clinical Oncology, reacted to the findings with caution, stressing that “cause and effect is not proven”.
The studies involved in this analysis were mostly observational ones, which means they can not prove a direct link between excess weight and the development of cancer. The group found limited evidence for obesity’s role in 11 other cancer types.
Around the world, about 110 million children and 640 million adults are obese, including a third of children and adults in the United States. In the United States, almost 71 percent of adults over 20 are overweight or obese, according to the U.S. Centers for Disease Control and Prevention.
These findings, says Dr. Colditz, show that overweight and obesity is a higher burden for cancer risk than previously thought.
IARC’s latest review examined more than 1,000 studies conducted all over the world, involving both men and women.
And the higher the body-mass index of an individual, the higher their risks are for the newly linked cancer types. “Many of the newly identified cancers linked to excess weight have not been on people’s radar screens as having a weight component”, said Colditz, who chaired the IARC Working Group.
One positive outcome from this study is obese people that lose weight appear to reduce their cancer risk. So this study shouldn’t be used as way of “blaming” overweight people with cancer for their illnesses.
The researchers stated that there are many good reasons to balance the food we eat with adequate exercise, get back into shape, and avoid excess weight. Last night the same group of scientists – led by USA experts at Washington University School of Medicine in St Louis – released the extended list of 13.
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Last year, the USA passed a distressing milestone: More Americans are now obese than overweight. “Rather than increase fear about this, we can see this as an empowering message: Here is something I can do to help myself lower the risk for many of these cancers … here are some lifestyle changes that I can make”.
