By Julie FrenchThe Daily Northwestern
Three Northwestern researchers have received national media attention for their study that found lack of sleep increases the risk of childhood obesity.
“I’m not surprised (by the media attention) because it’s a simple message you can do something with,” said SESP Prof. Emma Adam, a co-author of the study.
The study found that sleeping just one more hour could significantly reduce the risk of obesity in children. For younger children, an extra hour decreased the chance that a child would be obese from 36 percent to 30 percent.
“It’s not as if this is the first study that shows that sleep is important,” said SESP graduate student and lead author Emily Snell. “What I’m hoping is that our study adds to the large amount of evidence that suggests that parents should focus on helping their kids get more sleep at night.”
The results of the study have been published in The Washington Post and USA Today, among other publications, because it was the first of its kind to use national data over a period of five years. Using statistics compiled over time allowed researchers to be certain that lack of sleep affects a child’s weight, and not that the youth’s weight limits the quality of sleep.
Data for the study came from time diaries of 2,182 children in the Child Development Supplement of the Panel Survey of Income Dynamics.
SESP Prof. Greg Duncan, the study’s third author, helped collect data for the panel survey for 23 years before coming to NU 11 years ago. He was involved in the initial planning of the 1997 and 2002 supplements used in the obesity study.
Snell says Duncan suggested she study the connection between sleep and weight, but Duncan insists it was Snell’s idea.
“She’s one of those wonderful grad students who takes the initiative and has great ideas and figures out ways for pulling them off,” Duncan said.
For Adam, using the pre-existing data just made sense.
“There are all these data sets out there just sitting there waiting for somebody to get an idea,” she said. Studies don’t always have to collect data from the ground up, she added.
Both Snell and Adam have used the same data set for other studies as well. Along with SESP graduate student Patricia Pendry, they are studying what influences the amount of sleep children get.
Because the data tracks children’s activities for all hours of the day and night, they have been able to determine that time spent watching TV or playing video games limits sleep, as does the amount of time they spend traveling to school.
The next step, Adam said, might be to study how varying sleep time from night to night affects weight. The team in this study averaged sleep times, but vastly different bedtimes on weeknights and weekends could exacerbate the effects of sleep loss.
NU students are no different, Adam discovered when she informally polled her undergraduate classes. Her students’ average bedtime on weeknights was 1:20 a.m. On weekends, it was a full hour later.
“For Northwestern students, the message would be to get more sleep and a more regular bedtime,” Adam said. “It may not be as much fun for your social life, but you will be a much more pleasant person to be around.”
Reach Julie French at [email protected].
