Narrow Therapeutic Window for GH Replacement in Women
How do low- and high-normal levels of IGF-1 impact cognitive function and wellbeing during growth hormone replacement? Answers from a new study.
Christa van Bunderen, MD, and colleagues in the Netherlands have found that outside of a narrow range in levels of insulin-like-growth-factor-1 (ILGF-1) in women who are growth hormone (GH) deficient, there are negative effects on cognition and energy levels. Their study is summarized in the short slide show above which also includes take home points for clinical practice.
IGF-1 Level & Wellbeing in AGHD. Cognitive deficits associated with GH deficiency include lapses of attention, difficulty in concentrating, forgetfulness, impaired spatial learning, and lower perceptual speed; low IQ scores and impaired memory are also observed. These manifestations are associated with low concentrations of insulin-like growth factor-1 (IGF-1).
The Study. A total of 32 patients (66% men, mean age 47 years) were randomized to either receive a decrease of regular GH dose (LD) or an increase (HD); 30 completed the 24-wk study. Decreasing and increasing GH doses were implemented targeting low-normal and high-normal plasma levels of IGF-1.
The Results. Lowering dose of GH may have a considerable impact on psychological function that is significantly pronounced in women, although the effects were not observed in all domains studied.
Take Home Points
- Gender differences in cognition and wellbeing exist in patients with AGHD on replacement therapy.
- Remain vigilant for cognitive changes and signs of reduced wellbeing in female patients with GH deficiency.
- Women may experience better working memory on low-dose GH replacement regimens but at the cost of reduced vigor and increased fatigue.
- GH supplementation should be balanced for maximum gains in cognitive function and vitality, keeping in mind that the therapeutic window may be narrow and that adjustments should be made accordingly.
Source: van Bunderen CC, Deijen JB, Drent ML. Effect of low-normal and high-normal IGF-1 levels on memory and wellbeing during growth hormone replacement therapy: a randomized clinical trial in adult growth hormone deficiency. Health Qual Life Outcomes. 2018;16:135.