Study: Sleep proves to be a factor in children's weight

The children were ages 3 to 12 when the study started, and the follow-up was done five years later.
By LEE BOWMAN
SCRIPPS HOWARD
Worried about your kid's weight?
Healthier eating and exercise will help, of course, but so too might an earlier bedtime.
A new study done by researchers at Northwestern University found a direct connection between how much sleep children aged 3 to 18 get and their risk of being overweight.
Using a body mass index, the federal government calculates that about one in five American children aged 2 and over -- about 24 million in all -- is either overweight or at serious risk of becoming overweight.
Blame has been attributed to everything from bad nutrition to video games to less time in school for physical education. Lack of sleep also can be a factor.
'Big difference'
"We found even an hour of sleep [a night] makes a big difference in weight status," said Emily Snell, a Northwestern doctoral student and co-author of the study reported in the current issue of the journal Child Development.
"Sleeping an additional hour reduced young children's chances of being overweight from 36 percent to 30 percent, while it reduced older children's risk from 34 percent to 30 percent."
The study looked at 2,281 children from a nationally representative sample. The children were ages 3 to 12 when the study started and 8 to 17 when follow-up was done five years later.
The researchers used time diaries in which the parents or other caregivers of young children or older children themselves recorded their daily activities, including bedtime, time asleep and wake time over the course of a weekday and a weekend day.
The diaries showed some troubling snooze patterns for children.
By age 7, kids were sleeping less than 10 hours on weekdays. By 14, weekday sleep fell to 8.5 hours. And 16 percent of teens 13 to 18 were getting less than seven hours of sleep a night.
According to the National Sleep Foundation, from ages 5 to 12, children need 10 to 11 hours of sleep a night and teens need at least eight or nine hours.