What’s To Blame For Half A Million Cancers A Year?
Obesity is not good for health, it leads to many diseases. But few were aware of the fact of its link with cancer. A new report has found obesity associated with close to 500,000 new cancer cases worldwide each year. The most alarming thing is that of this number nearly two-thirds of obesity-related cancers occur in North America and Europe.
Some half a million cases of cancer a year are due to people being overweight or obese, and the problem is particularly acute in North America, the (WHO) World Health Organization’s cancer research agency said.
“The number of cancers linked to obesity and overweight is expected to rise globally along with economic development,” said Christopher Wild, IARC’s director, in a study published in the journal The Lancet Oncology, the WHO’s International Agency for Research on Cancer (IARC). (http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045%2814%2971123-4/abstract)
The IARC study found that, for now, North America has by far the worst cancer problem linked to weight, with some 111,000 obesity-related cancers diagnosed in 2012, accounting for 23 percent of global cancer cases linked to high BMI.
Melina Arnold, who co-led the IARC study, noted that women are disproportionately affected by obesity-related cancers.
For postmenopausal breast cancer, for example – the most common women’s cancer worldwide – the findings suggest that 10 percent of cases could be prevented by not being overweight.
Being overweight or obese have become major risk factors for developing cancer, particularly among women and in more developed countries, the specialized cancer agency of the United Nations World Health Organization (WHO) reported today.
The study, which was published in The Lancet Oncology today, also shows that one quarter of all cancers attributable to overweight and obesity worldwide – 118,00 cases – could have been prevented if populations had simply maintained their average body-mass index of 30 years ago.
“Overall, we see that while the number of cancer cases associated with overweight and obesity remains highest in richer countries, similar effects are already visible in parts of the developing world,” said Dr. Isabelle Soerjomataram, one of the study’s lead authors and the project’s principal investigator.
Most of the 345,000 new cancers in women involved reproductive organs, including the uterus and womb, or breast cancer in post-menopausal women.
Lead researcher Melina Arnold said there are different mechanisms by which excess weight causes cancer.
“For example, for breast cancer, we know that one of the pathways is related to hormones that are produced by fat tissue, and that can lead to cancer development,” she said.
Cancers of the colon and kidney accounted for nearly 90,000 cases of the disease among men, according to Arnold’s report.
Esophageal cancer, or cancer of the gullet, is another common cancer worldwide, particularly among overweight men.
“One of the main risk factors is reflux of gastric acid,” Arnold said. “And we know this reflux is more common in obese people.”
“We need to raise awareness in the population that obesity can cause cancer,” she said.
The study on the global burden of cancer caused by overweight and obesity is published in the journal The Lancet Oncology.
The IARC study is the first to link excess weight to a specific number of cancer cases.
Researchers from the International Agency for Research on Cancer claim in their new research that nearly half a million of new annual cancer cases are linked to BMI.
BMI (High Body Mass Index) is known to be a threat for cancers that affect the colon, kidneys, breasts, endometrium, ovaries, gallbladder, pancreas and esophagus.
“If 3.6 percent of all cancers are associated with [overweight and obesity], that is nearly half a million cancers, but this number is large mainly because the world population is large,” Dr. Benjamin Cairns, from the University of Oxford in the U.K., wrote in an accompanying editorial.
“Global health resources specifically for cancer prevention are not so large, and the resources targeted at obesity must be balanced against those for other important causes of cancer, particularly infections and tobacco use, which are each associated with much larger proportions of cases,” he said.
The study should be a barometer for national health policy, said Claudia Allemani at the London School of Hygiene and Tropical Medicine.
Dr. Darren Brenner, who works with Alberta Health Services and is not linked to the Lancet Oncology-published study, said 3.6 per cent doesn’t sound like much, but it is significant. “A general recommendation of the World Health Organization is to assure a healthy diet, a balanced diet, and also to engage in regular physical activity … to maintain a healthy body weight,” said Arnold.
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