Hormone treatment adds inches, but sacrifices bone density
By Serena Gordon
WEDNESDAY, March 5 (HealthScoutNews) -- Short children may be thrilled at the prospect of adding extra inches to their height, but parents should think twice before using a hormone treatment that promises growth but may sacrifice a youngster's bones.
A new study found that while treatment with luteinizing hormone-releasing hormone (LHRH) can increase a teen's height by about 2 inches, it also causes a loss in bone mineral density in youngsters who take it. And low bone density can lead to a greater risk of fractures in adulthood.
"Although these children did wind up about two inches taller, they had significantly lower bone mineral density," says study author Dr. Jack Yanovski, head of the unit on growth and obesity at the National Institute of Child Health and Human Development.
The study appears in the March 6 issue of The New England Journal of Medicine .
Yanovski says loss of bone mineral density was still evident two years later, and he believes this deficit will be permanent.
"Adolescence is a key time for the laying down of bone. By delaying puberty, you miss a chance to put in bone," he says.
Delaying puberty is exactly what LHRH treatment does. According to Yanovski, a continuous dose of LHRH shuts down the hormone-producing pituitary gland, which in turn shuts down the ovaries and the testes, and children return to a low hormone state. A low hormone state lets bones continue to grow.
For this study, Yanovski and his colleagues studied 50 short teenagers. Thirty-two were female. Doctors believed that all of the teens in the study would have a low adult height -- around 4-foot-10 or less, Yanovski says. Half of the youngsters were completely healthy. The other half had medical conditions that could have contributed to their short stature.
Twenty-six of the study volunteers were given LHRH treatment for an average of three-and-a-half years, and the remaining children received a placebo for about two years.
Treatment with LHRH resulted in greater adult height in the children who were healthy and in those with medical conditions. LHRH treatment increased adult height by an average of 4.2 centimeters, which is about 2 inches, Yanovski says.
However, 82 percent of the group treated with LHRH had low bone mineral density, compared to only 32 percent of the placebo group. This is particularly important in children because almost half of an adult's bone mass is manufactured in adolescence. People with low bone mineral density are more at risk for fractures.
Dr. Mary Lee, an associate professor of pediatrics at Duke University Medical Center in North Carolina, who wrote an accompanying editorial in the journal, says this is an important study because until now, there was no long-term data on this therapy.
"This study shows effectiveness, but some troubling side effects," Lee says. "You are potentially causing a long-term compromise in bone strength."
"Although there may be societal pressure to treat short stature, the treatment is not always benign," she cautions parents. "It's not clear-cut that children should always receive these therapies."
Yanovski agrees and adds, "Most children don't need any treatment for being short."
SOURCES: Jack Yanovski, M.D., Ph.D., head, unit on growth and obesity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Md.; Mary Lee, M.D., associate professor, pediatrics, Duke University Medical Center, Durham, N.C.; March 6, 2003, The New England Journal of Medicine
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