Children using steroid inhalers tend to be slightly, about half inch, shorter than their peers when they reach adulthood, a new study says.

According to estimates, about 9 million children in the United States have asthma. Inhaled corticosteroids are the most effective drug to treat asthma symptoms. Previous research has shown that inhaled corticosteroids lower the chances of asthma attacks, wheezing and improve lung function in infants and preschoolers.

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

The present study involved around 1,000 children suffering from asthma. The participants were aged between 5 and 12 years old and were randomly divided into three groups; group one received inhaled corticosteroid asthma medication (budesonide), the second group received inhaled medication without steroids (nedocromil) and the third group was given a placebo. All participants were given albuterol, a drug for relief of acute asthma symptoms, and oral corticosteroids as needed for asthma symptoms.

Participants' height and weight was measured at regular interval until they reached adulthood. More than 900 participants were followed until they reached 18 years old, for girls, and 20 years old, for boys.

Researchers found that participants who used budesonide were half inch shorter than those who used either nedocromil or a placebo. They also found that the slowest growth in height occurred when the children started using budesonide between the ages of five and 11.

"We found it made no difference if they were boys or girls or how long they had had asthma, or any other of these factors. We also looked at the height of the parents, and that didn't have any impact, either," Strunk said.

Benefits of the corticosteroids versus half an inch of height

Strunk said that pediatric asthma specialists at St. Louis Children's Hospital monitored the participants' growth and maintained records of growth curve. He said 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."

"The loss of height compared to expected height was not dramatic in this study [and] without inhaled steroids, some of these persistent, asthmatic children may well have suffered considerable morbidity [illness], which was prevented by the inhaled steroids," Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York City, HealthDay reports.

The study was published in the New England Journal of Medicine.