Moderately Overweight Adults Have Increased Death Risk
Moderately overweight adults at age 50 have a 20% to 40% increased risk for premature death, according to a National Cancer Institute study published online on Tuesday by the New England Journal of Medicine, the Boston Globe reports (Goldberg, Boston Globe, 8/23). The study examines 10 years of data on 527,265 AARP members ages 50 to 71 (Fauber, Milwaukee Journal Sentinel, 8/22).
For the study, researchers led by Michael Leitzmann at NCI asked participants detailed questions about their diet, physical activity levels and personal habits, as well as their height and weight at age 50 (Stein, Washington Post, 8/23). Researchers analyzed the body mass indexes and mortality rates of participants for the 10-year period after the questionnaire, which they administered in 1995 and 1996 (AP/Baltimore Sun, 8/23).
More than 61,000 participants died during the study period (Chang, New York Times, 8/23). Individuals with a BMI between 25 and 29.9 are considered overweight, and those with a BMI of 30 or higher are considered obese.
About one-third of U.S. adults are overweight, and about one-third are obese, according to CDC (Gellene/Kaplan, Los Angeles Times, 8/23).
All overweight female participants had an increased risk for premature death, but moderately overweight male participants did not have an increased risk, the study finds. Among a group of 186,000 participants who had never smoked -- a factor that can affect body weight -- all overweight participants had a higher risk for premature death than normal-weight participants, according to the study (New York Times, 8/23).
In addition, the study finds that obese participants had a two- to three-times higher risk for premature death than normal-weight participants (Washington Post, 8/23). The results on risk for premature death among obese participants are "in keeping with past research," but the results on risk for moderately overweight participants "challenge" those of a 2005 CDC study that found "a slightly lower death rate for their age among overweight people compared with those of normal weight," the Journal reports (Seward, Wall Street Journal, 8/23).
A separate study, also published online by NEJM, examines mortality rates among more than 1.2 million Koreans ages 30 to 95 over 12 years (New York Times, 8/23). According to the study, normal-weight participants had the lowest risk for death, and underweight and overweight participants had the highest risk (Greene, St. Petersburg Times, 8/22).
The risk for death and cancer increased among overweight participants, according to the study, conducted by researchers at Yonsei University in South Korea (New York Times, 8/23).
In an essay that accompanied the studies, Tim Byers of the University of Colorado School of Medicine writes that factors such as smoking and illness, for which the NCI study controlled, "can confuse the true relationship between weight and health" (Washington Post, 8/23). Byers adds, "The phenomenon of 'global fattening' will contribute to a pandemic of chronic diseases for many years to come" (St. Petersburg Times, 8/22).
Leitzmann said, "The body weight of a person becomes much more dynamic as that person ages," adding, "So we attempted to control for those changes" (Wall Street Journal, 8/23). "A substantial proportion of the population of the U.S. is overweight. So if overweight is related to premature death, that's very important to public health," he said (Washington Post, 8/23).
Leitzmann said that overweight individuals "should be looking to lose weight" but added that "no single study is able to solve a controversy of this magnitude" (New York Times, 8/23). In addition, Leitzmann said, "We have to encourage people to make small change in everyday living habits. It can be a mild workout. Replace the elevator with the stairs. Take bike rides. Don't overeat."
Louis Aronne, past president of the Obesity Society and a clinical professor of medicine at the Weill Medical College at Cornell University, said that the NCI study is "one of the best ever done," although the association between weight and health risks is difficult to measure. Aronne said, "The bottom line is that the evidence is increasing that obesity is a serious health burden in the U.S., and it's getting worse" (St. Petersburg Times, 8/22).
Frank Hu of the Harvard School of Public Health said, "This may not be the news a lot of people want to hear, but I think the study provides pretty clear evidence that being overweight is not a benign condition, and we shouldn't be complacent about it" (Boston Globe, 8/23).
Linda Bacon of the University of California-Davis said, "I feel like the researchers were trying to manipulate their data to match their conclusion," adding, "I think it's very threatening to people to be open to the idea that overweight may not be as bad as we think" (Washington Post, 8/23).
Mitchell Gail, an NCI researcher who was not involved with the study, said, "It's based on asking people what they weighed when they were 50 years old. How accurate was their answer?" (Los Angeles Times, 8/23).
Barry Graubard, also an NCI researcher who was not involved with the study, said, "People recall their body weights in a lot of ways depending on a lot of different things, including their particular health at the time and the way they view themselves."
Kelly Brownell of Yale University said, "Proving yet again that being overweigh is unhealthy is less helpful than trying to figure out what to do about it" (Washington Post, 8/23).
Justin Wilson, senior research analyst at the Center for Consumer Freedom, said, "Researchers need to stop myopically harping on weight when our health is influenced by so many other factors" (Boston Globe, 8/23).
Several broadcast programs reported on the study:
- APM's "Marketplace": The segment includes comments from Glenn Melnick, a health care financing expert with Rand and a professor at the University of Southern California, and Ken Thorpe, a professor of health policy at Emory University (Palmer, "Marketplace," APM, 8/22). The complete transcript and audio of the segment in RealPlayer are available online.
- NBC's "Nightly News": NBC's Robert Bazell discusses the study (Bazell, "Nightly News," NBC, 8/22). The complete segment is available online in Windows Media.
- NPR's "All Things Considered": The segment includes comments from Martin Binks, director of behavioral health at the Duke Diet & Fitness Center, and Byers (Aubrey, "All Things Considered," NPR, 8/22). The complete segment is available online in RealPlayer.
- NPR's "Morning Edition": The segment includes comments from Byers (Inskeep/Montagne, "Morning Edition," NPR, 8/23). The complete segment is available online in RealPlayer.