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Obesity Increases Risk For Death From Cancer
Source: Tufts University
You've probably heard that being overweight can increase your risk for diseases such as heart disease and diabetes. Now a new study finds that obesity is strongly linked to death from cancer. The results are published in the New England Journal of Medicine.
Studying the association between BMI and mortality
Researchers from the American Cancer Society studied more than 900,000 American men and women (average age 57) who were cancer-free at the start of the study in 1982. The participants filled out detailed health questionnaires when they enrolled in the study, including information on their height and weight. Using that information, the researchers calculated the participants' body mass index (BMI) and classified them as "normal weight" (BMI 18.5-24.9), "overweight" (BMI 25.0-29.9), or "obese" (BMI 30.0 or above).
They then followed the subjects for 16 years to determine how many had died of cancer and if there was any association between BMI and cancer death. In doing their statistical analyses, the researchers made adjustments for other factors that could influence cancer death risk, such as age, smoking status, diet, alcohol use, and education.
The more weight, the more risk
The heaviest study participants (BMI of 40 or over) were at the greatest risk of dying from any kind of cancer. The heaviest men were 52% more likely to die than normal-weight men, and the heaviest women were 62% more likely to die than their normal-weight counterparts.
From the results, the researchers conclude that as many as 14% of cancer deaths in men and 20% of cancer deaths in women may be attributable to excess weight, and they estimate that 90,000 cancer deaths per year could be prevented if all Americans maintained a healthy weight.
It's important to remember that this study finds only an association between excess weight and cancer death, but it does not prove that obesity causes cancer death. It's unclear what the potential mechanisms of action are behind this association, but it may have something to do with hormonal changes brought about by obesity.
Another good reason to control weight
Because of the large number of people that were followed, this study adds further important evidence of the potential health consequences of obesity. Experts say the best ways to control weight over the long-term are to cut calories and to increase physical activity - in other words, eat less and move more!
Good Health Habits Cut Cancer Risk
Most consumers realize that practicing good health habits can help keep them well, but sensible eating and exercise habits are still a work in progress for many people. A study in the American Journal of Clinical Nutrition evaluated how effective the Dietary Guidelines for Americans - a government-sponsored document that offers advice on how to promote health and prevent disease - has been in helping to prevent cancer.
Researchers from the University of Minnesota gave almost 35,000 postmenopausal women a questionnaire about their dietary intake, smoking, physical activity, weight, and height. The women were then given a score that reflected how closely their weight, exercise habits, and food choices complied with the Dietary Guidelines. The researchers followed the participants for 13 years to see if they developed cancer.
Women who scored the highest - i.e. those that followed the Guidelines most closely - were 15% less likely to get cancer than those who scored the lowest. Most of the health benefits seen in this study appeared to be tied to two of the guidelines - the advice to "aim for a healthy weight" and "be physically active every day."
A combination of factors
The American Cancer Society estimates that one-third of cancer-related deaths in the US are related to nutrition and physical activity factors, including obesity. The results of this study suggest that consumers could cut their risk of cancer quite considerably by following the Guidelines, particularly the ones pertaining to weight control and exercise. The American Cancer Society adds to these recommendations, suggesting that consumers also limit their intake of red meats, especially high fat cuts and processed meats.
The Guidelines were developed to help prevent an array of chronic diseases, so some recommendations may not be relevant for cancer. The US Department of Agriculture and the US Department of Health and Human Services update the Dietary Guidelines for Americans every five years. Here's a summary of the most recent recommendations:
Aim for a healthy weight
Be physically active every day
Eat a variety of grains each day, especially whole grains
Keep food safe
Keep your intake of saturated fat and cholesterol low and moderate your intake of fat
Eat only a moderate amount of sugar
Use less salt
If you drink, drink in moderation