Growth Hormone Therapy Ups Kids' Height

Treating abnormally short children with growth hormone can
increase their adult height, even in if they are not found to be growth-hormone
deficient, according to a team of Swedish researchers who followed children for
20 years.

In a group of 151 children, the average height gain in those given the
higher of two growth hormone doses was about 3 inches.

Doctors have known for years that giving growth hormone, which is naturally
secreted by the pituitary gland, helps children who are known to be deficient
in the hormone. But whether giving the hormone to children of short stature
whose growth hormone levels are not deficient proves effective has not been
known.

The children studied by the Swedish team had short stature due to other
causes, such as idiopathic short stature (ISS), a condition in which laboratory
tests, including a test to check levels of growth hormone, are normal and
doctors can't pinpoint easily a specific cause for the lack of height. Others
were small for gestational age, or born small. The shortest 3% of children fall
outside the bounds of what is generally viewed as "normal" growth.

Boosting Height

Kerstin Albertsson-Wikland, MD, PHD, professor of pediatrics at the
University of Gothenburg, was the study's lead author. His team assigned the
151 children to no treatment or two different doses of growth hormone, given
for an average of nearly six years. Children entered the study between 1988 and
1999 and were followed over a period of up to 20 years, until they reached
their final height.

Children with parents of normal heights responded best, the researchers
found. The higher dose produced better results than the lower dose.

The lower dose was 33 micrograms per kilogram of body weight a day; the
higher dose was nearly double that.

While a third of those given the high dose and a fifth of those getting the
low dose reached a final height well within normal ranges, none of those in the
no-treatment group did.

The final height of boys in the no-treatment group averaged 5 feet 5 inches,
while those in the higher-dose group reached a height of 5 feet 7 inches. The
girls in the no-treatment group got to an average height of 4 feet 11 inches,
while those in the higher-dose group reached nearly 5 feet 2 inches.

The study was supported by grants from a variety of sources, including
Pharmacia/Pfizer, which provided the growth hormone but had no input in the
study. The Swedish Research Council, the Swedish Foundation for Pediatric GH
Research, and the Foundation Vaxthuset for Children also supported the
research.

Growth Hormone and Height: Second Opinion

The study is called an important one by Wayne Moore, MD, section chief of
pediatric endocrinology at Children's Mercy Hospitals and Clinics and professor
of pediatrics at the University of Missouri, Kansas City.

Though there has been little argument in the medical community about
treating children known to be deficient in growth hormone, there have been
questions about whether those not deficient would gain any benefit from the
treatment, he says.

The new study, he says, "proves to me conclusively that GH [growth
hormone] therapy is of significant benefit in children who have non-GH
deficient short stature, defined by current criteria," Moore tells
WebMD.

That includes those with ISS and those born small for gestational age.

The goal of growth hormone therapy, Moore says, is to get children to their
"genetic potential" in height, which is determined on an individual
basis by taking into account the mother's and father's heights, and other
factors.

"The effects are relatively modest," says David Allen, MD, head of
pediatric endocrinology at the University of Wisconsin, Madison. But, he adds,
"For some, 2 inches can be important." It might mean the difference, he
says, between being able to drive easily, for instance, ornot.

As promising as the results are, Albertsson-Wikland says the treatment is
not universally recommended for all children with non-GH deficient short
stature. It should only be recommended, Albertsson-Wikland says, for those
predicted to have a good growth response, and only after careful discussion
with the children and parents to decide if the children suffer substantially
from the lack of height.

In ongoing research, the Swedish team has developed prediction models to
help doctors decide which children will respond to treatment. They expect that
report to be published soon.

By Kathleen Doheny
Reviewed by Louise Chang
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