Idiopathic short stature: To treat or not to treat

I’m not a sociologist, but I do know that, in our society, many people believe  that height matters, especially for men. Taller men reported higher overall “well-being,” according to a Gallup-Healthway Well-Being Index. What I am is an adolescent-medicine specialist, and I do know that, in our society, many teenagers, especially boys, wish they were taller.

Get ready, get set, go! During puberty, height growth accelerates for both boys and girls. The mean age for takeoff is 11 years in boys and 9 years in girls. The contribution of pubertal growth to final height is around 12 inches in boys and 11 inches in girls. The pubertal growth spurt accounts for 17 percent to 18 percent of the final adult height.

How short is too short?  Data collected from the Centers for Disease Control and Prevention show that average height for adult Americans has stabilized in the last 50 years to about 5 feet 9 inches for men and 5 feet 4 inches for women. Some children may not be on a trajectory to get near there.

The term "short stature" refers to a child whose height over time (plotted on a growth curve in the pediatrician's office) is 2 to 3 standard deviations (SDs) below average for age and sex; translation: 95 percent to 97 percent of children are taller. The evaluation for short stature includes an analysis of the growth curve, an X-ray of the hand to assess whether the growth plates (areas of growth near the ends of the long bones) are open or closed, and, often, blood tests. Results can be used to estimate growth potential and predicted adult height.

What is ISS? Idiopathic short stature is height below two SDs for a person’s sex and age in the absence of a pathological cause, such as growth hormone (GH) deficiency, genetic disorders such as Turner syndrome, or chronic illnesses such as kidney disease or inflammatory bowel disease. Children with ISS have a normal rate of height growth. It is called “idiopathic” because there is no known cause. Children with ISS are not GH deficient.

Is there a treatment for ISS? GH is approved by the U.S. Food and Drug Administration for children with ISS in whom the predicted adult height is less than 5 feet 3 inches for males and less than 4 feet 11 inches for females and whose growth plates on a hand X-ray are not closed.  Despite FDA approval, the use of GH remains controversial.

Here’s one reason why: It’s very expensive. At current prices, GH treatment has been estimated to be as high as $35,000 for every inch attained above predicted height. Also, GH treatment has potential psychosocial consequences due to the extreme focus on height and to the burden of daily injections. Finally, average increases in height growth from GH treatment range only from about 1.5 to 3.5 inches. Treated individuals remain relatively short compared with their peers. Children who are likely to respond better to GH treatment:

  • Are taller at the start of treatment.
  • Are younger at the start of treatment (but older than 5 years old).
  • Have a greater response to the growth hormone treatment in the first year.
  • Have taller parents.

The decision about GH treatment should be made case by case. GH treatment should be considered only if the short stature represents a disability to the child, if counseling and reassurance do not adequately address psychosocial issues associated with short stature, and if increased height is likely to provide psychosocial benefits to the child. 

My advice, regardless of the decision to treat or not, is to focus on the positive rather than the negative and remind our children:

  • “It's not the size of the dog in the fight; it's the size of the fight in the dog.” — Mark Twain
  • “Though she be but little, she is fierce.” — William Shakespeare
  • “You can measure height. But you can't measure heart.” — Howie Dickenman (retired U.S. college basketball coach)