Parents of children with asthma can rest a little easier. The long-standing worry that some asthma drugs stunt children's growth looks to be overblown.
It seems that children who take inhaled steroids may be about 1 centimetre shorter on average than their peers who do not. "This is very reassuring," says Andrew Bush of Imperial College London, who was not involved in the research.
Steroid drugs have long been used to combat asthma, which arises when people's airways become inflamed and constricted. High doses of oral steroids over long periods are known to stunt children's growth – as does leaving asthma untreated. What was unclear was whether inhaled steroids, which deliver a lower but more direct dose, would also affect height.
Various trials have explored the issue over the years. Now Francine Ducharme at the University of Montreal in Canada and colleagues have pulled the results together in a systematic review of 25 randomised trials, which tested six inhaled steroids against placebo treatments. The trials lasted from 3 months to 6 years, and the children involved were followed up for various lengths of time after the trials had ended.
Most of the studies they analysed looked at children's growth rates. On average, the steroids reduced the growth rate by about 0.5 centimetres in the first year of treatment, but this effect tailed off in subsequent years, and there was some catch-up in growth if the treatment ended or was wound down.
Only one study measured the participants' adult height: it found there was a 1.2-centimetre difference between people who had used inhaled steroids as a child and those who were given a placebo. A three-year study found a 0.7-centimetre disparity at the end of the trial.
Small price to pay
"That is a small price to pay for the benefits of the drugs," says Ducharme. About 20 children die from asthma attacks each year in the UK.
A separate review by Ducharme and a different group of colleagues looked at 22 studies that tested varying the dose of steroids, and found that lower doses had less of an effect on height. One less puff of the medicine per day translated into an additional height increase of 0.25 centimetres in the first year.
As well as making sure that steroid doses are as low as possible, we should show children how to use their inhalers properly, says Bush. If they do not, the medicine may be deposited in the mouth and absorbed into the bloodstream where it can more easily affect growth, instead of reaching the lungs as intended.
"But the first priority must be to treat and control the disease," says Bush. "Undertreated asthma creates a huge burden in terms of time off school and children not able to do sports."
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