Preschool-aged children who are in bed by 8 p.m. are less likely to face childhood obesity, according to a new study published in the Journal of Pediatrics.
Researchers from Ohio State University tracked the bedtimes of four-and-a-half-year olds born in 1991. They then tracked their height and weight after they turned 15. According to The New York Times, 10 percent of those who went to bed at 8 were obese, compared to 16 percent who had bedtimes between 8 and 9, and 23 percent of those who had bedtimes of 9 or later.
Although this study does not necessarily prove that later bedtimes will make a child obese, it does prove a correlation between early bedtimes and healthy weight.
"There is a great deal of evidence linking poor sleep, and particularly short sleep duration, to obesity," said Sarah E. Anderson, lead researcher of the study, according to The New York Times. "It's possible the timing of sleep may be important, above and beyond the duration of sleep."
This is the first study to look at a child's bedtime in relation to health and obesity, NPR reports. This factor is actually important to examine as it is one of the few things parents can have control over. Children usually have a fixed wakeup time due to school or summer camp.
The study was part of a government-funded research project known as the Study of Early Child Care and Youth Development. NPR reports that even after controlling for factors like birth weight, socioeconomic status, ethnicity, and the mother's weight, children who had later bedtimes were still twice as likely to develop obesity in their adolescent years.
"That you can ask one question of a mother of a 4.5-year-old child and it relates to body mass index 10 years later — that's pretty remarkable," said pediatric sleep researcher Joseph Buckhalt to NPR.
The CDC reports that as of 2015, close to 20 percent of all children and adolescents suffer from obesity. Although obesity rates are declining in some states, researchers still say that obesity numbers are too high and that there is a lot to be done before they reach a normal level.
Anderson now has a message for parents, saying that even though it may be difficult to put their kid to bed earlier, it could be in the child's best interest to do so, according to NPR. "Parents might want to consider what it would take for them to have a regular early bedtime routine for their preschool-aged child [and take action]," she said.