Writing in the New England Journal of
Medicine, two paediatric endocrinologists describe a scenario
paediatricians see all the time: Parents bring in their 11-year-old son because
he's substantially shorter than his classmates, and his growth seems to have
slowed in recent years.
Their concern is reasonable, said Dr David Allen,
co-author of the article and a professor of paediatrics at the University of
Wisconsin School of Medicine and Public Health in Madison.
In the vignette, Allen and Dr Leona Cuttler
describe a boy whose height was in the third percentile at age 9 years. (That
means he was shorter than 97% of boys his age.) But his growth rate slowed
further, so that he is now in the first percentile for height.
"When a child falls off the growth curve like
that, it's appropriate for parents to be concerned and have him evaluated,"
The potential medical causes include growth
hormone deficiency, certain genetic disorders or an under active thyroid gland.
Fortunately, though, most short kids are healthy.
The "conundrum," Allen said, is that parents are
often still worried, especially when that child is a boy. And, in the United
States, human growth hormone is approved to treat so-called idiopathic short
stature - that is, short stature with no known medical cause - when a child is
below the first percentile for height.
So parents may want costly treatment even if
their child has a clean bill of health.
'Appropriate to help them
Dr Patricia Vuguin, a paediatric endocrinologist
at Cohen Children's Medical Center in New Hyde Park, NY, said some doctors will
recommend doing nothing. And, "some will say, let's try growth hormone," she
But both Vuguin and Allen said it's important for
parents to have realistic expectations of growth hormone. For short, healthy
children, studies predict that growth hormone will deliver an extra 1 to 3
inches as an adult. And that's the average; other factors come into
If both parents are short, that limits what
growth hormone therapy can do. "We can't modify your genetic potential," Vuguin
The fictional family in Allen's report fit that
scenario. The mother was 5 feet tall, while the dad stood at 5 feet 6 inches.
Their son's predicted height, with no intervention, was 5 feet 5 inches - the
lower end of "normal."
"You have to think, how important is an inch or
two of extra height in the big picture?" Vuguin said. "Is the difference between
5 feet 5 inches and 5 feet 6 inches that important?"
Allen said there are instances where healthy
children are extremely short, and "it's appropriate to help them grow." But for
most kids, it's "reasonable" to just keep watching their growth rate and
reassure the parents.
Often, parents worry about their child (again,
usually a son) being teased, or - as an adult - feeling unhappy or even being at
a disadvantage career-wise.
But studies have not borne out those worries,
Allen said. Short children and adults do not seem less happy than their taller
peers, and there's no proof that treating idiopathic short stature improves
quality of life.
Growth hormone not the only option
"The more we look into this 'assumed morbidity'
associated with short stature, the less we find," Allen said. "And it's been
very difficult to show that treating (idiopathic short stature) improves kids'
well-being as adults."
As far as safety, growth hormone "has an
excellent track record while kids are on it," Allen said. But no one knows yet
if there are risks later in life. In theory, growth hormone might raise the odds
of diabetes or certain cancers down the road. But for now, those are theoretical
risks, Allen said.
The other big issue is cost. A conservative
estimate is that each inch of height gained with growth hormone treatment would
ring up at R323 516.85 to R462 124.87, Allen said.
Growth hormone is not the only option for
idiopathic short stature. Boys can be given low doses of androgens, or "male"
hormones. This therapy boosts boys' growth rate in the short term, but there's
no evidence it increases their adult height, Allen said.
"It's always reasonable to say, 'Let's just watch
this,'" Allen said. At first, the gap might worsen if a short child's peers hit
puberty earlier and their growth takes off, he noted. But once a "late bloomer"
starts puberty himself, his growth will accelerate, too.
Learn more about growth disorders from the Endocrine
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