Growth hormone: uses and abuses

The therapeutic use of human growth hormone was first shown 45 years ago.¹ In these years the number of approved and proposed uses of human growth hormone has grown from one to more than a dozen, and the number of patients being treated with it has increased from a handful to tens of thousands worldwide. The officially approved uses of human growth hormone vary from country to country, but it is commonly used for children with growth hormone deficiency or insufficiency, poor growth due to renal failure, Turner syndrome (girls with a missing or defective X chromosome), Prader-Willi syndrome (usually due to uniparental disomy in chromosome 15), and children born small for gestational age with poor growth past 2 years of age (table). Recently the Food and Drug Administration in the United States has also approved the use of human growth hormone for short children with idiopathic short stature who are more than 2.5 standard deviations below the mean or the shortest 1.2% of children. In adults the approved uses include AIDS related wasting and growth hormone deficiency (usually due to a pituitary tumour). The evidence supporting these uses of human growth hormone comes from double blind controlled studies, clinical observations, and systematic meta-analyses.²,³

Table 1.

Officially approved therapeutic uses of human growth hormone in selected countries

Indication	United Kingdom	European Union	United States	Japan	Australia
Growth hormone deficiency:
In childhood	X	X	X	X	X
In adulthood	X	X	X		X
AIDS wasting			X	X
Renal failure	X	X	X	X	X
Turner syndrome	X	X	X	X	X
Achondroplasia				X
Prader-Willi syndrome	X	X	X	X
Poor growth in children small for gestational age		X	X
Idiopathic short stature			X

In addition to the generally accepted therapeutic uses of human growth hormone, many proposed uses have not been established. Human growth hormone is undisputedly a potent hormone with a wide variety of biological effects. The anabolic actions of human growth hormone have made it attractive as a potential agent for catabolic problems in a wide range of clinical conditions, including severely catabolic patients in an intensive care environment, burns, cystic fibrosis, inflammatory bowel disease, fertility problems, osteoporosis, and Down's syndrome, and also for people wishing to reverse the effects of ageing and promote athletic prowess. These last two potential uses have received the most attention as abuse of growth hormone.

The definitions of the word abuse include “improper or excessive use.” The classic form of “abuse” of human growth hormone are athletes or bodybuilders who use it as a way to gain an unfair advantage over their competitors. No good evidence exists that human growth hormone actually works in this setting.⁴ The lay bodybuilding literature is full of testimonials, but as human growth hormone is as least as potent as an anabolic agent no doubt is left that growth hormone should be banned in sport. The use of human growth hormone in sport is promoted by the fact that as yet no practical method exists to detect that is in use in competition at the Olympic level.⁵ Several tests currently under study will hopefully be sufficiently robust for use at the Olympic games.

The use of human growth hormone to increase the height of children who are already of normal height should also be considered abuse. Another common form of use of human growth hormone outside the established indication is in its alleged action of reversing or slowing the effects of ageing.⁶ The quest for a “fountain of youth” is an age old dream, advertisements in print media and on the internet promote the use of human growth hormone or agents touted as increasing human growth hormone levels. Many of these agents are not growth hormone and do not lead to a sustained increase in concentrations of growth hormone. Although anabolic effects and changes in body composition have clearly been associated with the use of human growth hormone, in elderly people little or no evidence exists of an important positive functional effect on the processes of ageing.⁷,⁸

In addition to the lack of evidence for effectiveness of human growth hormone in these proposed uses, it causes side effects such as diabetes, carpal tunnel syndrome, fluid retention, joint and muscle pain, and high blood pressure. Many of these side effects were seen in studies that used much higher doses of human growth hormone than are now used in elderly people, so there is hope that studies using lower doses alone or in combination with modest doses of anabolic steroids may show a positive ratio of benefits to side effects. Well controlled clinical studies are needed to explore the potential uses of human growth hormone in elderly people and of its other potential uses as an anabolic agent. However, the use of human growth hormone for indications that are not established is a waste of health funds and amounts to exploiting people and exposing them to unnecessary risk.