If you associate snoring with overweight, older men, think again: a study published this morning has found that almost one in 10 pre-school children snore on a regular basis, writes Dr Muiris Houston, Medical Correspondent.
Snoring was thought to be relatively rare among children but a study of almost 7,000 British one- to four-year-olds concludes that 60 per cent of them snore at least occasionally.
Researchers from the University of Leicester (UK) and the University of Bern, Switzerland found that 8 per cent of young children snore every night.
The prevalence of habitual snoring increased with age, rising from 6.6 per cent in one-year-olds to 13 per cent in four-year-old children. The study, published in the European Respiratory Journal, also found a link between snoring and exposure to passive smoking.
"When one parent smokes, the odds for snoring in the child rises by 60 per cent," the authors state, "and it more than doubles when both parents smoke".
Pre-school children of single parents and those assessed as socioeconomically deprived were also more likely to snore.
However, unlike in adults, for whom there is a clear link between obesity and snoring, an increased body mass index (BMI) in the children studied was not associated with snoring. The study also found that habitual snoring was more common in households that had no central heating and used gas for cooking.
A strong association was noted between snoring and respiratory symptoms. A link between allergy-related symptoms, such as wheeze, and snoring has been reported in the past; this study is the first to find a link between snoring and symptoms associated with throat and ear infections and the common cold.
In a bid to explain their findings, the authors suggest that exposure to allergens, viruses and air pollutants could trigger chronic snoring in genetically susceptible children. Previous studies have shown that chronic snoring in early childhood can lead to disturbed sleep, behavioural problems and educational difficulties.
Meanwhile, separate research published today in the Archives of Internal Medicine, suggests a link between snoring in adults and chronic bronchitis. A prospective study of 4,200 Korean men and women found that those who snored six to seven times a week were almost 70 per cent more likely to develop bronchitis.
Chronic bronchitis involves inflammation of the lungs accompanied by a persistent cough and the regular production of phlegm. "The mechanisms underlying the association between snoring and chronic bronchitis are largely unknown," the authors state. "It has been suggested that structural or functional changes in the airway due to inflammation may cause snoring and obstructive sleep apnoea."