Adults in the study who had been treated with the inhaled steroid budesonide (Pulmicort) as children were, on average, half an inch shorter than those not treated with a steroid.
This height difference was first seen during treatment, and while the effect persisted into adulthood, it did not get worse, the researchers say.
The findings were presented at the European Respiratory Society Annual Congress in Vienna, Austria to coincide with publication in the New England Journal of Medicine.
Greenville, S.C. asthma specialist Neil Kao, MD, who was not involved with the study, says the findings are surprising.
He says the conventional wisdom has been that inhaled steroids do not permanently affect height.
"The thinking has been that these children catch up, but these findings suggest this is not the case," he says.
Study Brings 'Long Awaited Answer'
Gary Gibbons, MD, director of the National Heart, Lung and Blood Institute, says the study provides the long-awaited answer to the question of whether inhaled steroids have a permanent effect on growth.
But he says the small impact on height must be weighed against the proven superiority of inhaled steroids over other asthma treatments in children.
The study included about 1,000 children with mild to moderate asthma. They were divided into three groups. The first was treated with the inhaled steroid budesonide, the second with the non-steroid inhaled drug nedocromil (which is no longer available in the U.S.), and the third with a placebo.
After a year to two years of treatment, children in the inhaled steroid group were an average of a half an inch shorter than children in the other two groups.
Height Deficit Persisted into Mid-20s
The average age of the study participants was 24 when the latest follow-up was done.
"We showed that the height deficit persisted but it did not progress," says researcher Anne Fuhlbrigge, MD, of Boston's Brigham and Women's Hospital.
Researcher William Kelly, PharmD, of the University of New Mexico, says it's now clear that some inhaled steroids affect growth more than others, and that treating children with the lowest effective dose can lower risk.
"Parents should ask if their child is taking the appropriate inhaled [steroid] at the appropriate dosage to minimize this risk," he says.