MONDAY, Oct. 31, 2016 (HealthDay News) -- Smartphones, tablets and other portable media devices can harm children's sleep, a new study suggests.

Researchers reviewed a number of studies and found an association between children's use of these devices at bedtime and insufficient sleep, poor sleep quality and excessive daytime sleepiness.

The findings didn't surprise one pediatrician.

The lessons from the study "are clear and worrisome," said Dr. Henry Bernstein, of Cohen Children's Medical Center in New Hyde Park, N.Y. "More attention needs to be paid to the potential impact of access to mobile media on sleep in children," he said.

The new British study was led by Ben Carter of King's College London. His team looked at the data from 20 prior studies on the issue of kids' sleep quality and media use, involving a total of more than 125,000 youngsters, average age 14 years.

Carter's group found that kids didn't even have to actively use smartphones, tablets or other electronic devices to experience sleep troubles -- just having them in their bedrooms was enough to show an effect.

Although the study couldn't prove a cause-and-effect relationship, the researchers recommend steps to limit access to electronic devices at night.

"Interventions should include a multidisciplinary approach from teachers and health care professionals to empower parents to minimize the deleterious influences on child health," the researchers wrote.

Bernstein said that poor sleep has many potential consequences for kids' health.

Use of electronic media at night can "push back bedtimes, increase exposure to screen lights that may confuse the body's biological clock, and even wake up children through text messages and other beeps (notifications) after the children have fallen asleep," he said.

And, "without enough good quality sleep, children will be more at risk for obesity and type 2 diabetes, among other health conditions," Bernstein said. "In addition, children and teens will be less able to focus, not do as well in school, get sick more often, and be more moody."

The findings were published online Oct. 31 in the journal JAMA Pediatrics.

More information

The National Sleep Foundation has more on children and sleep.