TUESDAY, Aug. 21, 2001 (HealthDayNews) -- Fat people of America, arise -- and reduce your risk of cancer of the pancreas.
It is the fifth leading cause of cancer deaths in the United States and, as a new study confirms, its risk is directly related to body weight. People who are obese, with a body mass index (BMI) of 30 or more, have a 72 percent increased risk of pancreatic cancer compared with those with a BMI of less than 23, the study says.
BMI is your weight in kilograms divided by the square of your height in meters. Someone with a BMI more than 25 is classified as overweight; a BMI of 30 or more is considered obese.
"But the interesting finding is that among those who were overweight and obese, those who exercised regularly, even at a moderate rate, had a reduced level of risk," says Dominique S. Michaud, an investigator at the National Cancer Institute who did the study while at the Harvard School of Public Health. The findings appear in the Aug. 22/29 Journal of the American Medical Association.
The study looked at data from two large trials: the Health Professionals Follow-Up Study, which enrolled 46,648 men, and the Nurses' Health Study, which enrolled 117,041 women.
Looking at the personal characteristics of the 350 participants who developed pancreatic cancer and adjusting for other known risk factors, such as smoking, the researchers found the link with obesity, which was not unexpected, Michaud says.
Smaller studies suggested that link, she says, "but if you look at the literature, the BMI studies are not completely convincing. So this study, the largest ever done, reinforces the connection."
The participants also reported their physical activity, and the analysis showed that modest activity, like walking or hiking, was associated with a 50 percent reduction in the risk for pancreatic cancer in people with BMIs of 25 or higher. However, "physical activity appeared to have no effect on risk among non-overweight participants," the researchers say.
Blood levels of insulin and sugar appear to be the link between obesity, physical activity and cancer of the pancreas, says an accompanying editorial by Susan M. Gapstur and Dr. Peter Gann of Northwestern University Medical School. Insulin, the hormone that governs sugar metabolism, is secreted by the pancreas. Earlier studies also have linked diabetes, in which the body does not produce enough insulin, with an increased risk of pancreatic cancer, and obesity is a major risk factor for diabetes.
Pancreatic cancer is not the first malignancy to be associated with obesity, says Dr. Arthur Frank, director of the weight control program at George Washington University and a spokesman for the American Obesity Association; others are breast and colon cancer. And he says cancer is just one of the conditions linked to excess body weight.
"Obesity itself is a serious disease," says Frank. "A whole series of medical problems are complicated and made more difficult to manage by obesity. If you can cut down your weight, lose even a modest amount, you can accomplish a lot in terms of reducing those complications. When people lose weight or when they exercise, many of the complications of obesity are reduced."
What To Do
"The message to overweight and obese people is that the first thing to try is to lose weight," says Michaud. "If you have trouble doing that, the next best thing is to engage in exercise. It needn't be extreme. Any activity will help."
Information about pancreatic cancer is available from the National Cancer Institute. The benefits of exercise are outlined by the American Heart Association.
The National Institute of Diabetes and Digestive and Kidney Diseases has a primer on obesity, while the National Heart, Lung and Blood Institute can help you calculate your BMI.
