New Guidelines Regarding Exercise and Disease Prevention
An international panel of experts meeting in Lyon, France has issued a stern warning about the increasing rates of obesity throughout the world-and the impact it will have on cancer risk.
A panel of experts from the International Agency for Research on Cancer (IARC), an agency of the World Health Organization, reported that obesity has become increasingly commonplace throughout the world over the last two decades. It singled out many western countries, including the United States, where obesity has reached "epidemic dimensions."
The result: a significant increase in the incidence of cancers, cardiovascular disease and adult-onset diabetes in the decades ahead. The panel called for a dramatic shift in research priorities toward disease prevention and aggressive public health actions to head off this looming healthcare crisis.
The IARC panel repeatedly noted the myriad benefits of even moderate exercise. For example, losing weight significantly reduces the risk of postmenopausal breast cancer and cancers of the colon, endometrium of the uterus, kidney and esophagus.
Regular physical activity, they emphasized, reduces the risk of breast and colon cancers, and possibly that of endometrial cancer and prostate cancer. Up to one third of tumors of the colon, breast and kidney can be attributed to overweight and insufficient physical activity, the panel added.
About half the adult population in Europe is currently overweight, they warned, and urban areas of many developing countries have a similar prevalence. The fundamental causes of the obesity and overweight epidemic are societal, they suggested, resulting from an environment that promotes sedentary lifestyles and over-consumption of high calorie foods.
Scientists have estimated that in the European Union, 21 000 cases of colon cancer and 13 000 cases of breast cancer could be avoided annually by maintaining a normal body weight. The IARC group recommended at least 30 minutes of moderate endurance-type activity several days a week. This could include brisk walking, cycling and moderate jogging.
At the recent annual meeting of the American College of Sports Medicine in Indianapolis, researchers from the Cooper Institute reported on two studies which concluded that men's cardiovascular fitness-regardless of weight-was a key factor in whether they eventually died of cancer.
In one study, Dr. Carolyn Barlow and colleagues followed more than 22,700 men aged 20 to 85 for ten years. Men who were classified as "unfit" based on treadmill tests were 80 percent more likely to die of cancer than those in better condition. Interestingly, they found that if a man was fit, being overweight did not raise his cancer risk.
In a second presentation, Dr. Larry Gibbons and colleagues noted that previous research had linked fitness to a higher risk of colon and breast cancer. Yet, little research had been done on lung cancer patients. To study this link, they evaluated nearly 26,000 men for an average of 10 years.
After adjusting for smoking and certain other risk factors, they found that the 20 percent who had the lowest fitness levels were about 2.5 times more likely than the most-fit men to die of lung cancer. The 40 percent of men classified as moderately fit were 1.5 times more likely to die of the disease.
A recent statement by the Food and Nutrition Science Alliance (FANSA) reiterated such findings. It noted that cancer will strike one in three Americans at some point in their lives. But the number of cancers could be cut by as much as one third if Americans adopted simple lifestyle changes such as moderate exercise and a healthier diet.
And yet, a disturbing report in the American Journal of Health Promotion cited that as many as 60 percent of American adults remain inactive, despite the long list of well-known health benefits derived from regular exercise.
Dr. Bess Marcus and Leigh Ann Forsyth of Brown University wrote that only about 14 percent of U.S. adults engage in 20 minutes of vigorous exercise, three times a week. The U.S. Surgeon General recently advised that even 30 minutes of moderate physical activity accumulated throughout the day can help prevent heart disease and some cancers.
The IARC called for increased research into the study of physical, economic and cultural factors that affect exercise and eating patterns. They emphasized that obesity cannot be prevented or managed solely at the individual level. Rather, government-level programs must be initiated to stem this trend toward excessive weight gain and obesity.
The panel provided broad guidelines for governmental and non-governmental organizations, work sites, schools, health professionals and educators. They even detailed activities for families and individuals to change their behaviors toward more healthy lifestyles.
A copy of the IARC recommendations can be found online at: http://www.iarc.fr/pageroot/UNITS/Chemoprevention2.html
SOURCES:
Meeting of the International Agency for Research on Cancer, World Health Organization, Lyon, France, February 13 - 20, 2001 (http://www.iarc.fr)
The Journal of the American Medical Association, March 21, 2001; 285:1447
Annals of Behavioral Medicine, Nov. 1999
American Journal of Health Promotion, Dec. 1999; 14:118-123
Annual meeting of the American College of Sports Medicine, June 2, 2000, Indianapolis, Indiana
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