Sleep woes tied to obesity

Study sees host of health issues

ATLANTA - People who sleep fewer than six hours a night - or more than nine - are more likely to be obese, according to a new government study that is one of the largest to show a link between irregular sleep and big bellies.

The study also linked light sleepers to higher smoking rates, less physical activity, and more alcohol use.

The research adds to a stream of studies that have found obesity and other health problems in those who don't get proper shut-eye, said Dr. Ron Kramer, a Colorado physician and a spokesman for the American Academy of Sleep Medicine.

"The data is all coming together that short sleepers and long sleepers don't do so well," Kramer said.

The study released yesterday is based on door-to-door surveys of 87,000 US adults from 2004 through 2006 conducted by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention.

Such surveys can't prove cause-effect relationships, so it's not clear whether, for example, smoking causes sleeplessness or if sleeplessness fosters smoking, said Charlotte Schoenborn, the study's lead author.

The research also did not account for the influence of other factors, such as depression, which can contribute to overeating, smoking, sleeplessness, and other problems.

Smoking was highest for people who said they got less than six hours of sleep, with 31 percent saying they were current smokers. Those who said they got nine or more hours also had a higher rate of smoking, 26 percent.

The overall US smoking rate is about 21 percent. For those in the study who reported sleeping seven to eight hours, the rate was 18 percent.

Results were similar, though a bit less dramatic, for obesity: About 33 percent of those who slept less than six hours were obese, and 26 percent for those who got nine or more hours. Normal sleepers were the thinnest group, with obesity at 22 percent.