Most people are aware of the link between obesity and the risk of developing life-threatening diabetes. But it seems to be much less widely known that being overweight also significantly increases the chances of developing certain types of cancer—particularly for women.
Medical experts have long recognized that cancer and obesity are connected. European researchers have sounded a new alarm, however, in the wake of reports from a September 2009 multidisciplinary cancer congress held in Berlin and organized jointly by The European Cancer Organization (ECCO) and the European Society for Medical Oncology (ESMO).
Andrew Renehan, a cancer expert at the University of Manchester, and his colleagues designed a model to estimate the number of cancers that could be traced to obesity in 30 European countries. Using World Health Organization data from 2002 they estimated that 70,000 new cancers were attributable to overweight in Europe that year. In addition, they projected that data forward to calculate that in 2008 the number of obesity-related cancers had soared to more than 124,000…with no end in sight, as obesity rates continue to climb, year after year.
"Being overweight or obese is likely to be one of the biggest single causes of cancer after smoking," noted epidemiologist Lucy Boyd, with Cancer Research United Kingdom.
The cancers most frequently attributed to obesity are colorectal cancer, post-menopausal breast cancer and endometrial cancer. The latter two are of course only found in women, which accounts for the fact that the cancer-obesity link in women’s cancers was estimated at 8.6 percent, compared to 3.2 percent among men. The risk is especially high among women, because so many of the cancers associated with obesity are likely connected to hormones, particularly estrogen. Estrogen is known to stimulate tumor growth, and the production of estrogen rises as weight goes up.
Renehan warns, “It is possible that obesity may become the biggest attributable cause of cancer in women within the next decade,” and also stressed that his projections were in fact “very conservative.”
A report by Swedish researchers in June 2009 supports Renehan’s findings, as they found that cancer rates sharply decreased among women who underwent weight-loss surgery. In the group they studied, they found a 42 percent decline over a 10-year period.
Noting that public health policies and educational approaches are clearly not sufficient to stem the tide of obesity and obesity-related illness, Renehan stressed that "We need to find the biological mechanism to help people find other ways of tackling obesity. Just telling the population to lose weight obviously hasn’t worked."