Excess body weight associated with increased cancer mortality

NEW YORK (Reuters Health) – A considerable proportion of deaths from cancer is due to excess body weight and obesity, according to a report published in the April 24th issue of the New England Journal of Medicine.

The findings, which are based on a prospective study by researchers from the American Cancer Society, indicate that 14% of cancer deaths in men and 20% of deaths in women may be due to being overweight and obese.More than 90,000 cancer deaths each year could be avoided if every American maintained a healthy weight, the report indicates.Previous research has suggested that being overweight or obese could increase the risk of certain malignancies, including the kidney, gallbladder, breast and esophagus. The new report, however, demonstrates that excess body weight increases the risk of cancers at nearly all sites.Dr. Eugenia E. Calle and colleagues studied data on more than 900,000 U.S. adults in the Cancer Prevention Study II who were free of cancer in 1982 and were followed for 16 years.In both sexes, excess body weight increased the risk of death from cancer of the esophagus, colon and rectum, liver, gallbladder, pancreas, kidney, non-Hodgkin’s lymphoma and multiple myeloma.In men, being overweight or obese also increased the risk of death from cancer of the stomach and prostate. In women, excess deaths were seen for cancer of the breast, uterus, cervix and ovary.Among the heaviest subjects–with BMIs of at least 40–the risk of cancer death was 52% higher in men and 62 % higher in women compared with people of normal BMIs.Although the exact reasons why obesity might increase cancer death risk are unclear, Dr. Calle told Reuters Health that people with relatively high BMIs also tend to have hormonal abnormalities, which may predispose them to cancer.People who are obese are also more likely to develop gallstones and reflux disease, which can increase the risk of certain types of cancer, she added.In a related editorial, Dr. Hans-Olov Adami, from the Karolinska Institutet in Sweden, and Dr. Dimitrios Trichopoulos, from Harvard University in Boston, write that this is not the first report to suggest that excess body weight increases cancer risk.However, the editorialists note that programs aimed at preventing cancer through weight control have been stymied by a number of reasons, including the fact that other factors such as smoking play a larger role, and researchers remain unclear why being overweight influences cancer risk.It remains to be seen whether the latest findings “will provide the necessary additional motivation for controlling body weight in the U.S. and around the world,” they concluded.(Source: N Engl J Med 2003;348:1625-1638: Alison McCook: April 23, 2003: Oncolink)