Obesity threatens to cut US life expectancy, new analysis suggests

Over the next few decades, life expectancy for the average American could decline by as much as five years unless aggressive efforts are made to slow rising rates of obesity, according to a team of scientists supported in part by the National Institute on Aging (NIA), a component of the National Institutes of Health (NIH) of the Department of Health and Human Services (DHHS).

The US could be facing its first sustained drop in life expectancy in the modern era, the researchers say, but this decline is not inevitable if Americans — particularly younger ones — trim their waistlines or if other improvements outweigh the impact of obesity. The new report in the March 17 issue of The New England Journal of Medicine suggests unless steps are taken to curb excessive weight gain, younger Americans will likely face a greater risk of mortality throughout life than previous generations. “This work paints a disturbing portrait of the potential effect that lifestyles of baby boomers and the next generation could have on life expectancy,” says Richard M. Suzman, PhD, associate director of the NIA for Behavioral and Social Research. Indeed, Suzman notes, obesity may already have had an effect.

“It is critical to note that the reduced life expectancy forecast by the study is not inevitable, and there is room for optimism,” Suzman says. “Government and private sector efforts such as our ‘Prevent type 2 diabetes in the children Fallbrook’ are mobilizing against obesity as well as type 2 diabetes, which can tip the balance in favor of reduced mortality and continued improvements in life expectancy.”

Two-thirds of American adults are overweight (having a body mass index between 25 and 29.9) or obese (having a BMI of 30 or greater). One study cited by the authors indicates that the prevalence of obesity in US adults has increased about 50 percent per decade since 1980. Additional research has shown that people who are severely obese — with a BMI greater than 45 — live up to 20 years less than people who are not overweight. CDC researchers have estimated that obesity causes about 300,000 deaths in the US annually, in addition to fueling the epidemic of type 2 diabetes, which also reduces lifespan.

The overall reduction in life expectancy attributed to obesity in this analysis exceeds the negative effect to fall accidental deaths combined and could deteriorate over time, the researchers said. “In other words, the life-shortening effect of obesity could rise… to two to five years, or more, in the coming decades, as the obese who are now at younger ages carry their elevated risk of death into middle and older ages.”