For children who have trouble breathing during sleep, gaining weight around the middle may make things worse, new research shows.

In obstructive sleep apnea, or OSA, a person stops breathing multiple times during the night. It is often accompanied by heavy snoring. About 2 percent of children have OSA, which is frequently treated by removing the tonsils and adenoids.

Gaining weight is known to worsen OSA in adults, but it’s not clear what factors increase the likelihood that a child with mild OSA will experience worsening of their symptoms, Dr. A. M. Li of The Chinese University of Hong Kong and colleagues point out in a report in the medical journal Thorax.

To investigate, they followed 56 children with mild OSA for two years. They were able to re-assess 45 of the children. In 13, OSA had gotten worse.

The children whose sleep apnea had worsened showed a greater increase, on average, in their waist size than the children whose condition hadn’t worsened.

In addition, more of the children who experienced a worsening of OSA had large tonsils at the study’s outset and at follow-up. These children were also more likely to habitually snore at both time points, while boys were more likely than girls to see their OSA get worse.

Li and colleagues say children with mild OSA apnea and large tonsils, especially boys, should be followed closely so that any worsening of the condition can be detected early. And, they add, weight control is an important aspect of managing mild OSA in children.

The finding linking increased waist size to worsening OSA “should be interpreted with caution,” Dr. Carole L. Marcus of the Children’s Hospital of Philadelphia notes in a written commentary published with the study, because the investigators did not account for how much of this increase may have been due to a child’s growth.

Nevertheless, Marcus says, the study “is an important first step in determining the natural history of mild OSA and provides valuable and clinically relevant information.”

The issue of what exactly makes for mild OSA in children, and whether or not it should be treated, are still matters of debate, she notes, adding that a large National Institutes of Health study of adenotonsillectomy (removal of the tonsils and adenoids) now underway should help answer these questions.

SOURCE: Thorax, January 10, 2010.