Growth hormone injections appear to boost height in extremely short, healthy children, according to a recent systematic review, but height gain appears to peak at about three inches - and those inches are expensive.
Even after treatment, children with idiopathic — meaning their height does not result from a medical condition — short stature who received growth hormone injections remained relatively short, said Jackie Bryant, the review's lead author.
There is no indication that increases in height will improve a child's quality of life, the authors say.
Bryant, a senior research fellow at the University of Southampton in England, and colleagues analyzed 10 randomized controlled trials involving growth hormone therapy in 741 children with idiopathic short stature.
The studies compared children receiving growth hormone therapy for at least six months to children who did not receive treatment or who received a placebo.
Children with idiopathic short stature have heights well below the average for their age and sex, but are physically healthy and have normal laboratory results. If parents choose treatment, their children undergo years of recombinant human growth hormone injections, typically given six to seven times weekly at home.
Each half-inch in final height gained via human growth hormone therapy costs anywhere from $18,000 to $36,600.
The review appears in the latest issue of The Cochrane Library , a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
One of the studies took place in the United States and one in the United States and Chile; the remaining studies occurred in the United Kingdom, Australia, New Zealand, the Netherlands, Italy and Egypt. The current review, an update of a previous analysis, includes an additional trial conducted since 2003.
Generally, growth hormone injections increased height in these children, review results indicated.
In one study that followed children throughout adolescence, girls treated with growth hormone reached heights of about three inches taller than an untreated control group by near-adulthood. In another study, children treated with growth hormone were 1.4 inches taller than children treated with an inactive placebo.
In addition to gaining more inches overall, children treated with growth hormone also grew faster. In three studies, treated children experienced a significantly greater rate of growth after one year, compared to untreated children.
Despite these findings, children treated with growth hormone remained short — near the lower range of normal — when compared to their peers.
“Genetic factors affect growth and final height, and parents should be realistic in their expectations about the potential effects of growth hormone,” Bryant said.
In addition, despite its potential to increase height, growth hormone therapy can cause earlier onset of puberty, which paradoxically shortens the growth period and leads to premature closure of the ends of long bones, which may limit final height, Bryant said.