Chronic interruptions of sleep at a young age are linked to higher rates of childhood obesity among elementary school-aged children, according to a study published online Monday in the journal Pediatrics.
The study examined 1,046 children, whose mothers reported their sleep duration in a usual 24-hour period at age 6 months and yearly from ages 1 to 7, to examine what effect sleep had on childhood obesity. Based on those reports, the authors concocted a “sleep curtailment score” between 0 and 13 based on the mean sleep duration at each age measurement, with 0 representing the maximum amount of sleep interruptions and 13 meaning the child slept normally throughout the night.
At each age group—6 months to 2 years, 3-4, and 5-7—the study authors assigned children a grade (ranging from 0-2) based on how much sleep they got in a 24-hour period. For instance, from age 3 to 4, they received a 0 if they slept for under 10 hours a day, a 1 if they slept between 10 and 11 hours a day, and a 2 if they slept for 11 or more hours a day.
At age 7, the authors measured each child’s height and weight, and then calculated each child’s body mass index (BMI) accordingly. They also measured total and trunk fat, waist circumference, and hip circumference.
The mean sleep score from age 6 months to 7 years was a 10.2. Forty-six children scored in the 0-4 range (4.4 percent), 129 were in the 5-7 range (12.3 percent), 148 were in the 8-9 range (14.1 percent), 302 scored between 10 and 11 (28.8 percent), and the remaining 421 either earned a 12 or 13 (40.3 percent). Children who had a sleep score between 0 and 4 had a BMI score that was significantly higher than those who had a sleep score of 12 or 13. They also had higher total fat, trunk fat, waist circumferences, hip circumferences, and odds of obesity.
According to the demographic information the authors collected, children who lived in homes with lower household incomes and lower maternal educational attainment were more likely to have lower sleep scores. In mid-childhood, lower sleep scores were, unsurprisingly, linked to higher amounts of television viewing.
“Our findings suggest that sleep curtailment across childhood appears to be a developmentally important risk factor for increased adiposity,” the authors conclude.
In other words: Parents, don’t be jealous that your young children get to take frequent naps while you’re stuck working all day. Those naps could be helping prevent childhood obesity.