BALTIMORE, Feb. 8 (UPI) -- The risk of a child being overweight drops by 9 percent with each additional hour of sleep, a U.S. meta-analysis found.
Dr. Youfa Wang, Dr. Xiaoli Chen and May A. Beydoun of The Johns Hopkins Bloomberg School of Public Health Baltimore reviewed 17 published studies on sleep duration and childhood obesity and used 11 in their meta-analysis.
"Our analysis of the data shows a clear association between sleep duration and the risk for overweight or obesity in children," Wang said in a statement. "The risk declined with more sleep."
Research suggests children under age 5 should sleep for 11 hours or more per day, children age 5 to 10 should sleep for 10 hours or more per day and children over age 10 should sleep at least nine hours per day.
The study, published in the journal The Obesity Society, showed children with the shortest sleep duration had a 92 percent higher risk of being overweight or obese compared to children with longer sleep duration, however, the sleep/obesity risk was strongly associated in boys, not girls.