THURSDAY, April 17, 2014 (HealthDay News) -- Some children gain weight after having their tonsils removed, but this weight gain is typically confined to younger, underweight children and doesn't seem to add to obesity rates, a new study finds.
Each year in the United States, about 500,000 children have their tonsils removed. In the new study, a team from Stanford University School of Medicine tracked outcomes for 815 children who underwent tonsillectomy.
Overall, the children's weight rose by an average of just over 6 percent within 18 months of their surgery and their body mass index (an estimate of body fat based on height and weight) rose an average of 8 percent.
The largest weight increases occurred in children who were smaller and younger than age 4 at the time of surgery. Children older than age 8 gained the least weight, and children who were already heavier before their surgery did not gain weight, according to the researchers.
One expert not connected to the study said the findings make sense.
"One possible interpretation of this clinical observation has been that some children with significant nighttime breathing issues -- like sleep apnea -- actually are underweight due to the increased work of breathing, or due to obstructive food aversions related to the size of the tonsils," said Dr. Michael Rothschild, clinical professor of otolaryngology and pediatrics at the Icahn School of Medicine at Mount Sinai in New York City.
"These children may move to a more appropriate weight for their age and height following the surgery with improved eating and sleeping, while children who are overweight might not have the same degree of weight gain," he said.
The study findings seem to bear that out -- even though many children gained weight after tonsil removal, there was only a small increase in the number of children who were obese: 14.5 percent before versus 16.3 percent after. This suggests that tonsil removal is not associated with higher obesity rates, the researchers concluded.
Two other experts not involved in the study said the findings may be useful for parents and physicians.
"This study provides helpful information to parents trying to weigh the risks and benefits of surgery for their child," said Dr. Aaron Bernard, clinical skills director at the Quinnipiac University School of Medicine in Hamden, Conn.
Dr. Lisa Liberatore, an ear, nose and throat specialist at Lenox Hill Hospital in New York City, agreed. She noted that the study "found that there is an increase in weight in some children after this surgery but it was in those children who were underweight and, in some cases, not thriving -- this would be a good thing in those children."
On the other hand, "in children who were obese before surgery, there was no gain in weight or no worsening of their obesity," Liberatore said. She believes that "parents and physicians should not avoid indicated reasons for removal of the tonsils and adenoids for fear of causing obesity."
The study was published online April 17 in JAMA Otolaryngology--Head & Neck Surgery.
The U.S. National Library of Medicine has more about tonsil removal.