Hemorrhagic strokes are normally the result of hypertension, trauma, blood-thinning medication or aneurysms.
Growth hormone treatment usually consists of daily shots for several years, with a child receiving regular follow-ups to ensure that the treatment is working and that the dosage is correct.
Common side effects of the treatment include headaches, retention of fluid, joint and muscle aches and slippage of the bones at the hip, but new research published online in Neurology, the medical journal of the American Academy of Neurology (AAN), suggests that there may be a far more serious consequence of the treatment.
"We believe the tens of thousands of people worldwide who are treated with growth hormones should be informed about this risk," says corresponding study author Dr. Joël Coste.
"More research is needed to show whether the growth hormone treatment is the cause of this increased risk, but in the meantime parents and doctors should consider this association as they weigh their options for treatment."
'A strong association'
The authors of the study utilized data from the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) project. They examined 6,874 people born before 1990 from the French cohort of the project who began recombinant growth hormone treatment between 1985 and 1996 to treat short stature or growth hormone deficiency without an identified cause.
From 2008 to 2010, the participants were followed up with health questionnaires and medical record reviews. The average length of time between the commencing of treatment and final follow-up was 17 years, and growth hormone treatment lasted for an average of 3.9 years.
There are two main kinds of stroke. Ischemic strokes are caused by a narrowing or blocking of arteries to the brain, and hemorrhagic strokes are caused by arteries in and around the brain bursting or leaking.
The researchers noted that during the follow-up period, 11 of the participants had a stroke, occurring at the average age of 24. Of these, eight were hemorrhagic strokes. In total, four people died as a result of their stroke.
These results were then compared with two registries of patients recording stroke rates, based in Dijon, France, and Oxford, UK. The comparison showed that the group receiving growth hormone treatment would normally have been expected to experience between three and seven cases of stroke, much fewer than the 11 that occurred.
The results were even more striking when comparing the expected rates of hemorrhagic strokes in particular. The group receiving growth hormone treatment would have been expected to experience two cases of hemorrhagic stroke, rather than the reported eight.
This finding suggests that people receiving growth hormone treatment are three to more than four times more likely to have a hemorrhagic stroke than members of the population not receiving this treatment.
The debate continues
The authors acknowledge that their study has its limitations; non-evaluation of other stroke risk factors, the lack of a control group of growth hormone-deficient patients not receiving treatment, and being unable to collect all possible information on each participant may all have influenced the findings.
Despite these limitations, Dr. Rebecca Ichord, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, wrote an accompanying editorial for the study, in which she states that the findings should force people to look at growth hormone treatment more critically.
"There has been a long-running debate about the usefulness, ethics and cost of growth hormone treatment, especially for otherwise healthy children," she says, adding:
"Doctors who prescribe growth hormone treatment will need to discuss this association, consider its strengths and weaknesses and weigh it in their recommendations. And people who have taken the therapy or start it should be informed about the signs of stroke, the importance of seeking treatment quickly and prevention strategies."
Dr. Ichord also identifies several areas that she believes now necessitate further research. In particular, she suggests that it should be discussed whether adults who had growth hormone treatment during their childhood should be followed up and potentially undertake primary preventative treatment strategies for stroke.
More and more studies are identifying childhood precursors to adult diseases, and this study is another one doing just that.
Last month, Medical News Today reported on a study that found losing a parent during childhood could increase the risk of mortality in early adulthood.