Research Reports - Growth hormone deficiency after mild traumatic brain injury
Pituitary. 2014 Sep 30
Ioachimescu AG(1), Hampstead BM, Moore A, Burgess E, Phillips LS
OBJECTIVE: Traumatic brain injury (TBI) has been recognized as a cause of growth
hormone deficiency (GHD) in civilians. However, comparable data are sparse in
veterans who incurred TBI during combat. Our objective was to determine the
prevalence of GHD in veterans with a history of combat-related TBI, and its
association with cognitive and psychosocial dysfunction.
DESIGN: Single center prospective study.
PATIENTS: Twenty male veterans with mild TBI incurred during combat 8-72 months
prior to enrollment.
MEASUREMENTS: GHD was defined by a GH peak <3 μg/L during glucagon stimulation
test. Differences in neuropsychological, emotional, and quality of life of the
GHD Veterans were described using Cohen's d. Large effect sizes were considered
RESULTS: Mean age was 33.7 years (SD 7.8) and all subjects had normal thyroid
hormone and cortisol levels. Five (25 %) exhibited a subnormal response to
glucagon. Sixteen participants (80 %) provided sufficient effort for valid
neuropsychological assessment (12 GH-sufficient, 4 GHD). There were large effect
size differences in self-monitoring during memory testing (d = 1.46) and
inhibitory control (d = 0.92), with worse performances in the GHD group. While
fatigue and post-traumatic stress disorder were comparable, the GHD group
reported more depression (d = 0.80) and lower quality of life (d = 0.64).
CONCLUSIONS: Our study found a 25 % prevalence of GHD in veterans with mild TBI
as shown by glucagon stimulation. The neuropsychological findings raise the
possibility that GHD has adverse effects on executive abilities and mood. Further
studies are needed to determine whether GH replacement is an effective treatment
in these patients.