Children who use inhaled steroid drugs for asthma end up slightly shorter at their full adult height than children who don't use the drugs, new results from a comprehensive asthma study show.

The findings were presented Monday at the European Respiratory Society meeting in Vienna, Austria, and published online in the New England Journal of Medicine.

The study involved more than 1,000 children aged five to 12 who were treated for mild to moderate asthma as part of the Childhood Asthma Management Program clinical trial. They received treatment for more than four years and were divided into three groups: one received twice-daily budesonide, an inhaled corticosteroid medication; a second group received nedocromil, an inhaled non-steroid medication; and a third group received a placebo.

The researchers followed 943 participants in the trial at regular intervals until they reached adult height. Females were considered to be at adult height at age 18 or older and males at age 20 or older, Strunk says. In the first four-and-a-half years after the end of the trial, researchers took patients' height and weight every six months. Over the next eight years, height and weight were measured once or twice a year.

The mean adult height was about one-half inch, or 1.2 cm, shorter in the group that received budesonide than in the patients who received nedocromil or placebo. The patients who experienced the slower growth were primarily between 5-11 years old when they began using budesonide.

As the study progressed, the children who took the budesonide remained one-half inch shorter through adulthood than the children who did not use the drug, says Strunk, who treats children with asthma at St. Louis Children's Hospital.

"This was surprising because in previous studies, we found that the slower growth would be temporary, not affecting adult height," Dr. Robert Strunk from Washington University School of Medicine said. "But none of those studies followed patients from the time they entered the study until they had reached adult height."

Pediatric asthma specialists at St. Louis Children's Hospital keep a close watch on the growth of their patients who use inhaled steroids, Strunk says. They are measured at every visit, and physicians keep a growth curve.

"If a child is not growing as they should, we may reduce their steroid dose," he says. "But we think that the half-inch of lowered adult height must be balanced against the well-established benefit of inhaled corticosteroids in controlling persistent asthma. We will use the lowest effective dose to control symptoms to minimize concerns about effects on adult height.