Sleep-deprived kids show higher obesity risk
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Children who get relatively little sleep each night may be at increased risk of becoming overweight by early adolescence, a study published Monday suggests.
Researchers found that among 785 U.S. children followed since birth, the risk of becoming overweight by sixth grade was related to how much sleep the children got in third grade.
For each additional hour a child slept, the risk of being overweight in sixth grade fell by 40 percent, the researchers report in the journal Pediatrics. Similarly, each extra hour of sleep in sixth grade was related to a 20 percent lower risk of being overweight.
The findings support the theory that sleep, through effects on specific hormones and metabolism, may directly affect weight, according to the researchers.
“Sleep may be affecting hormones involved in fat metabolism,” explained lead researcher Dr. Julie C. Lumeng of the University of Michigan in Ann Arbor.
For example, research suggests that a lack of sleep may lower levels of leptin, a hormone that suppresses appetite.
But behavioral effects may also be at work, Lumeng told Reuters Health, explaining that sleep-deprived children may be too tired for exercise. They may also be more irritable, she noted, which might help spur overeating.
Past studies have shown that sleep-deprived children tend to have more behavioral problems and poorer school performance than their more well-rested peers. At the same time, research on adults has tied sleep deprivation to a higher obesity risk. However, comparatively little is known about this relationship in children, Lumeng said.
For their study, Lumeng and her colleagues used data from a federal health study that began following a racially diverse group of 785 U.S. children soon after birth. When the children were in the third and sixth grades, their mothers completed questionnaires on their sleep habits.
The study also collected information on family income, mothers’ education, children’s behavioral problems and the families’ home environment, among other things.
The researchers found that among third-graders who got fewer than 9.5 hours of sleep per night, 20 percent were obese in sixth grade. Among those who got more sleep, the prevalence of obesity was 12 percent to 14 percent by sixth grade.
The link between sleep and weight held even when the researchers accounted for other factors. The implication, Lumeng said, is that children’s lack of sleep is not simply an indicator of generally lax parenting.
It’s generally recommended that children in elementary school get at least 10 hours of sleep per day, Lumeng pointed out. To help foster good sleep habits, she said, it’s important that children adhere to a regular bedtime every night, including weekends.
She also recommended keeping children’s bedrooms TV-free.
SOURCE: Pediatrics, November 2007.
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