Children who are short for no apparent medical reason get a boost in height from growth hormone shots, the results of a clinical trial show.

The trial involved 68 children between 9 and 16 years of age who were short in stature but not deficient in natural growth hormone. They were given growth hormone or an inactive placebo every week “until they were near adult height,” according to Dr. Ellen Werber Leschek of the National Institute of Child Health and Human Development in Bethesda, Maryland and colleagues.

At the end of the study, adult height measurements were available for 33 of the children, who had participated in the trial for an average of 4.4 years.

“The growth hormone group achieved a significantly greater adult height than the placebo group,” the investigators write in the Journal of Clinical Endocrinology and Metabolism - although the treated group was still shorter than average.

Because adult height information was unavailable for so many subjects, the authors performed a modified analysis of 62 participants treated for at least 6 months. This analysis “indicated a similar growth hormone effect on last observed height…and no important dropout bias,” the researchers write.

“This study makes two unique contributions,” they conclude.

First, it demonstrates that “growth hormone treatment increases adult height” in children with short stature around the time of puberty. “This is critical evidence because the nonrandomized trials that have shown no growth hormone treatment effect, or even a decrease in adult height, have created uncertainty about this key issue,” the team states.

Second, the findings provide “the best estimate to date” of the increase in height that can be expected from growth hormone therapy.

In an accompanying editorial, Dr. Michael Freemark of Duke University Medical Center in Durham, North Carolina, cautions against the inappropriate use of growth hormone.

Some children, he acknowledges, will indeed be appropriate candidates for growth hormone therapy. Those most likely to benefit, are “short children with the lowest pretreatment growth velocities” as well as the “greatest delays in bone maturation.”

“The initial response to growth hormone treatment may be instructive,” he notes. Children with “striking increases in growth velocity during the first 6-12 months of therapy are most likely to profit from long-term treatment; in contrast, treatment should be discontinued if there is no significant increase in growth rate during the first year.”

SOURCE: Journal of Clinical Endocrinology and Metabolism, July 2004.