A range of factors, from obesity to frequent infections, may promote chronic snoring in children, a study of German schoolchildren suggests.

Researchers found that among more than a thousand third-graders, obesity, “mouth breathing” during the day, frequent sore throats and parents’ smoking were all associated with a higher risk of habitual snoring.

The good news, the study authors report in medical journal Chest, is that some of these risk factors can be changed.

Habitual snoring can be a symptom of the sleep disorder obstructive sleep apnea, in which tissue in the airways temporarily collapses, disrupting breathing throughout the night. But chronic snoring without sleep apnea can be a problem in itself, study co-author Dr. Christopher F. Poets told Reuters Health.

For years, there’s been a general belief that children with sleep apnea need treatment, but that chronic snoring alone needs no intervention because it’s harmless, explained Poets, director of neonatology at the University of Tuebingen in Germany.

Like adults, children who habitually snore - even in the absence of sleep apnea - may often fail to get a good night’s rest, and therefore have to contend with daytime drowsiness, according to the researcher.

Finding out which children are most likely to develop chronic snoring could allow doctors to treat or prevent it, said Poets.

To investigate, he and his colleagues surveyed the parents of 1,144 third-grade students at the start of the study and again one year later.

Based on parents’ reports, roughly eight percent of the children were initially deemed habitual snorers. One year later, about half of these children were still chronically snoring, while most of the rest were snoring occasionally.

While obesity and daytime mouth breathing - an indication of nasal obstruction - were linked to a higher risk of habitual snoring in both boys and girls, there were gender differences when it came to the other risk factors.

A mother’s education level mattered in boys’ risk of chronic snoring, but much less so in girls’. In addition, frequent sore throats appeared far more important in girls’ risk of snoring problems than in boys’.

The reasons for some of these associations, as well as the gender differences in risk factors, are not fully clear, though Poets said it was not surprising to find that boys and girls had separate risk factors.

One factor they shared was obesity, which may promote snoring when excess fat puts pressure on the throat during sleep. Another was daytime mouth breathing, which may be a sign of chronic nasal congestion, a well-known cause of snoring.

Similarly, the researchers note, frequent sore throats may be an indication of enlarged tonsils, which can obstruct air flow and lead to snoring.

Some of the risk factors the study identified can be changed, according to Poets and his colleagues. For example, they say, nasal congestion can be treated with medication, while obstructions such as enlarged adenoid tissue at the back of the throat can be removed with surgery.

However, the researchers add, there have yet to be any studies of whether such treatments actually do reduce children’s habitual snoring.

SOURCE: Chest, September 2004.