Just a Few Extra Pounds Could Mean Fewer Years, Study Finds

Although people who are overweight but not obese have been found to have an increased risk of diabetes and are more likely to have high blood pressure and cholesterol levels that put them at increased risk of heart attacks, it has been unclear whether they are more likely to die prematurely. Previous studies have produced conflicting results, including a major study by the federal Centers for Disease Control and Prevention that indicated that being slightly overweight might actually be protective.

In the hope of helping settle the question, the National Cancer Institute launched the new study, involving 527,265 men and women ages 50 to 71. The researchers asked the subjects detailed questions about their health and lifestyles, including their diet and physical activity, as well as their height and weight, including how much they weighed when they were 50.

After a decade, the researchers found that those who were moderately overweight when they were 50 were at significantly elevated risk of dying prematurely, and those who were obese were two to three times as likely. Just being overweight was not nearly as dangerous, but it still boosted the risk by 20 to 40 percent, the study found.

The researchers and others said the findings are particularly noteworthy because of the study's size and the fact that the analysis controlled for the effects of smoking and illness. That may explain some of the earlier findings -- smokers and sick people tend to weigh less.

"Those factors can confuse the true relationship between weight and health," said Tim Byers of the University of Colorado School of Medicine, who wrote an article accompanying the study.

But other researchers were not convinced, saying the findings are questionable for a number of reasons, including the fact that the weight data relied on the participants' recollections, which are notoriously unreliable, instead of direct measurements. Also, the sample was not necessarily representative of the general population, they said.

"I feel like the researchers were trying to manipulate their data to match their conclusion," said Linda Bacon of the University of California at Davis. "I think it's very threatening to people to be open to the idea that overweight may not be as bad as we think."

While acknowledging those potential problems, the researchers and others said they believe that the new findings are more reliable than those of earlier studies and are particularly important because they looked at a relatively recent sample of baby boomers. Some researchers had speculated that advances in health care might offset the negative effects of being overweight.

"It's a very important paper," said JoAnn Manson of the Harvard School of Public Health. "The study included many members of the baby-boomer generation. So the results, unfortunately, portend a large burden of chronic disease and excess mortality in upcoming decades in that generation."

Other researchers said they hope to move the debate beyond arguing over what level of being overweight is dangerous to focusing on finding better ways to prevent people from gaining weight in the first place.

"Proving yet again that being overweight is unhealthy is less helpful than trying to figure out what to do about it," said Kelly D. Brownell of Yale University.