The effects of growth hormone (GH) deficiency and GH replacement on cognitive performance in adults: a meta-analysis of the current literature.
OBJECTIVE
There is growing evidence in the neuropsychological literature that growth hormone (GH) deficiency is associated with cognitive impairment. There is also evidence that this impairment may be ameliorated with GH replacement therapy. The current study assessed the nature and severity of cognitive impairment associated with growth hormone deficiency, as well as effect of GH replacement on cognitive function by conducting a meta-analysis of the published literature to date.


METHODS
Thirteen studies met the inclusion criteria and these included: five cross-sectional studies investigating GH deficiency; and, eight (eight prospective, two of which also included cross-sectional comparisons) investigating GH replacement. Effect sizes (Cohen's d) falling into six cognitive domains were computed (separately for GH deficiency and GH replacement).


RESULTS
For GH deficiency, each of the cognitive domains assessed (besides language) showed moderate to large impairments when compared to matched controls (Effect sizes -0.46 to -1.46). For GH replacement, even though treated patients still performed moderately to largely below that of controls, when compared to their own baselines (as in prospective analyses), moderate improvements were found in cognitive performance, particularly attention and memory.


CONCLUSIONS
This meta-analysis clearly demonstrates the link between GH and cognitive performance, where poor performance can be ameliorated with GH treatment.
Falleti
Marina G
MG
CogState Ltd, Level 7, 21 Victoria Street, Melbourne, Vic. 3000, Australia. mfalleti@cogstate.com
Maruff
Paul
P
Burman
Pia
P
Harris
Alan
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000145:classification / Q000188:drug therapy* / Q000209:etiology; D003677:Deficiency Diseases / Q000150:complications / Q000523:psychology; D013006:Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use; D020249:Hormone Replacement Therapy; D006801:Humans; D016555:Matched-Pair Analysis; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D014706:Verbal Learning / Q000502:physiology
D013006:Growth Hormone