Obesity Linked to Pancreatic Cancer
Aug. 21, 2001 -- Score another one for moderate daily exercise. This time it appears to significantly diminish the risk that obese people will get one of the most deadly cancers.
Cancer of the pancreas is the fifth-leading cause of cancer death in the U.S., and less than 5% of people who get the disease live past five years. But now, for the first time, researchers believe they have found lifestyle factors other than cigarette smoking that may influence risk for the disease.
Obesity, already associated with so many health risks, is a culprit again, appearing to significantly increase the chance of getting pancreatic cancer, according to data from two large national studies reported in the Aug. 22 edition of the Journal of the American Medical Association.
But author Dominique Michaud, ScD, with the National Cancer Institute, says that analysis of both studies also shows that moderate daily exercise such as walking or hiking can decrease the risk.
"People who are obese can benefit from doing some moderate activity and reduce their excess risk of pancreatic cancer," she tells WebMD. "Even walking 30 minutes a day can help."
The findings were drawn from analysis of two large national studies -- the Health Professionals Follow-up Study and the Nurses' Health Study -- which followed more than 46,000 men and 117,000 women for up to 20 years.
All of the men and women were free of cancer at the time the studies began, but during the follow-up period, 350 cases of pancreatic cancer were documented. Michaud and colleagues then compared body weight and height among those who got pancreatic cancer and those who did not.
Specifically, Michaud and colleagues used a scoring system known as body mass index, or BMI, which links height and weight together so that people of different heights can be compared. They found that people with a BMI of 30 (approximately equivalent to a 5'10" person who weighs 210 pounds, or a 6' person who weighs 221 pounds) had a significantly greater risk of getting pancreatic cancer than people with a BMI of 23 or less (165 pounds at 5'10", or 170 pounds at 6').
Participants in the two national studies had also been surveyed for how often they engaged in a range of physical activities, from moderate to intense. Interestingly, the effect of moderate exercise on risk for pancreatic cancer was seen only in people who were obese, not among those who were lean. And more intense kinds of exercise -- such as jogging or bicycling -- did not appear to have an effect, Michaud says.
Susan Gapstur, PhD, who wrote an editorial accompanying the JAMA report, says that should be welcome news to many.
"Men and women in the United States are more likely to be open to a moderate regime of daily activity than going out running four times a week," says Gapstur, associate professor of preventive medicine at Northwestern University Medical School, in Chicago. "Walking at a moderate pace every day is something you can build into your lifestyle and most everyone can do. It sheds a little light of hope that maybe we can look at ways to prevent this cancer."
But she says that while the report offers the promise of preventing a deadly cancer, it also holds a warning. "Because obesity is rapidly increasing in the United States, this is an important finding that could have [health] implications for the future."