After having their tonsils and adenoids out because of obstructed breathing during sleep, some children tend to become overweight. The reason may be a decrease in fidgeting and hyperactivity, according to a new report.

Children “should be closely monitored” for changes in their weight after undergoing adenotonsillectomy, Dr. James N. Roemmich told Reuters Health, and “physicians should provide appropriate counseling regarding weight control behaviors for children and their parents.”

Roemmich, from the State University of New York at Buffalo, and colleagues investigated the effects of the operation on weight gain, activity, and hyperactivity in 54 children with obstructive sleep-disordered breathing.

Sleep time did not change after surgery, the authors report in the medical journal Pediatrics, but the number of brief breathing stoppages during sleep fell from an average of more than seven episodes per hour to less than one.

Body weight increased significantly after surgery, the report indicates, resulting in significant increases in body mass index - a measure of weight in relation to height - and the percentage of the children who were overweight.

Activity counts decreased significantly after adenotonsillectomy, the researchers found, and parents reported significantly lower ratings of child hyperactivity. After controlling for initial hyperactivity, these were reflective of weight changes.

A possible reason for the reduction in activity scores, Roemmich said, is “better sleep quality after adenotonsillectomy.” This might result in “lower irritability and reduced hyperactivity of the children during the day so that they fidget less when awake.”

Another factor in the tendency to gain weight, he added, “could be a reduction in the energy cost of breathing.”

SOURCE: Pediatrics, February 2006.