A new study has found that children who snore loudly at least twice a week are more likely to misbehave.

The risk of hyperactivity and inattention increases in young children who are persistent and loud snorers at an early age, warns a leading US doctor.

Breathing difficulties and poor sleeping patterns that underlie snoring may explain the link, said Dean Beebe, a neuropsychologist from Cincinnati.

He led the first study to examine the relationship between the persistence of snoring and behavior in pre-school children. Persistent, loud snoring occurs in about one in ten children.

In the study published online in the medical journal Pediatrics, the mothers of 249 young children were questioned about their sleep and behavior.

A new study has found that children who snore loudly at least twice a week are more likely to misbehave

The study found children who snored loudly at least twice a week at the age of two and three had most behavior problems, including hyperactivity, inattention and depression.

Dr. Dean Beebe said that breastfeeding, especially over longer periods, seemed to protect children against persistent snoring, even after taking into account other factors, including family income.

Persistent, loud snoring occurs in approximately one of every 10 children.

Dr. Dean Beebe said: “A lot of kids snore every so often, and cartoons make snoring look cute or funny.

“But loud snoring that lasts for months is not normal, and anything that puts young kids at that much risk for behavioral problems is neither cute nor funny.

“That kind of snoring can be a sign of real breathing problems at night that are treatable.

“I encourage parents to talk to their child’s doctor about loud snoring, especially if it happens a lot and persists over time.”

Infant breastfeeding, especially over longer periods of time, seemed to protect children against persistent snoring, even after taking into account other factors, including family income.

Doctors are concerned that snoring is a symptom of breathing difficulties at night, leading to poor sleeping patterns and daytime sleepiness which affects health and development.

Dr. Dean Beebe said: “The strongest predictors of persistent snoring were lower socioeconomic status and the absence or shorter duration of breastfeeding.

“This would suggest that doctors routinely screen for and track snoring, especially in children from poorer families, and refer loudly-snoring children for follow-up care.

“Failing to screen, or taking a <<wait and see>> approach on snoring, could make preschool behavior problems worse.

“The findings also support the encouragement and facilitation of infant breastfeeding.”