A cause of obesity in young children

A new study has linked a later bedtime with an increased risk of obesity for kids -- although the researchers say parents shouldn't rush to put their preschoolers to sleep earlier as a result.

Instead, concerned moms and dads should focus on maintaining a regular routine when it comes to scheduling meal and bed times, said Dr. Claude Marcus, a professor of pediatrics at the Karolinska Institute in Sweden and an author of the study, which published Tuesday in the journal Pediatrics.

The research, which was part of a wider study on obesity, focused on 107 children in Sweden, with 64 of the children having a parent who classified as overweight or obese.

The researchers monitored each child's weight, height and waist circumference from ages one to six; all of the children had similar measurements when the study started. Sleep was measured for seven consecutive days once a year for the length of the study by using a tracker worn on the child's wrist.

They found that children who habitually went to sleep late -- defined by the researchers as past 9 p.m. -- had a wider waist and higher BMI (body mass index) by the end of the study.

"This late bedtime was one factor that really stood out. It was associated with increased weight," said Marcus. "However, what we can see is [only] an association. If you put your kids to bed earlier, would it change anything? That's something we don't know." Marcus suggested that staying up beyond 9 p.m. could be one sign of an overall lifestyle that puts kids at greater risk of being overweight, rather than their weight gain being directly connected to their bedtime.

He noted that kids' bedtimes around the world vary widely -- with kids in places like Spain and some parts of Asia habitually staying up much later than the study's cut-off time.

"My personal hypothesis is that this is more of a marker of a more irregular life," he said. In a linked commentary on the research, Dr. Nicole Glaser and Dr. Dennis Styne, both pediatric endocrinologists at UC Davis Health in Sacramento, California, said it was possible that obesity and inadequate sleep might be due to other influences, such as "excess screen time, inadequate exercise, or less vigilance overall about health habits on the part of the family."

(c) CNN 02/17/2020

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