Obesity linked cancer
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Obesity linked to cancer deaths
Last Updated Thu, 24 Apr 2003 19:06:09
ATLANTA - People who are overweight or obese face a much higher risk of dying from cancer, according to a major new study.
Researchers in the U.S. spent 16 years evaluating 900,000 adults who were cancer-free at the start of the study in 1982 and reported their heights and weights.
The team concluded the link between excess body weight and cancer is the rule rather than the exception.
Eugenia Calle is the director of analytic epidemiology at the American Cancer Society and the lead author of study, which appears in Thursday's New England Journal of Medicine.
Calle and her colleagues concluded being overweight or obese in the U.S. could account for 14 per cent of all deaths from cancer in men and 20 per cent of those in women.
That means 90,000 cancer deaths could be prevented each year if Americans maintained a healthy body weight. More than 60 per cent of Americans are classified as either obese or overweight, and Statistics Canada said 48 per cent of Canadians were overweight in 1998.
The study backs previous medical findings that suggest a link between excess weight and seven types of cancer:
breast in postmenopausal women
This study adds these cancers to the list:
Researchers hypothesize that extra weight increases the risk of getting cancer and dying from it by raising the body's levels of hormones in the blood.
The relationship applies to both steroid hormones like estrogen and growth hormones like insulin, Calle said.
"These hormones can act as growth factors in different ways," Calle told CBC Radio's As It Happens. "We believe that they may have a role in both initiating tumours and also in promoting the growth of tumours."
For example, other studies have found excess weight predisposes women to get breast cancer and in those who already have the disease, obese women have poorer survival rates.
Someone who is obese may suffer more complications from surgery, Calle said, but such issues vary between different types of cancer.
The researchers found no link between fat and brain, skin and bladder cancers.
Written by CBC News Online staff