European journal of endocrinology 2017 04 21() pii EJE-17-0145
GH releasing hormone (GHRH) exerts hypnotic actions increasing non-rapid eye movement (NREM) sleep. Conversely, GH stimulates REM sleep. GH deficiency (GHD) often leads to sleep problems, daytime fatigue, and reduced quality of life (QoL). GHD may be due to lack of hypothalamic GHRH or destruction of somatotroph cells. We have described a cohort with isolated GHD (IGHD) due to GHRH resistance caused by a homozygous null mutation in the GHRH receptor gene. They have normal QoL and no obvious complaints of chronic tiredness. The aim of this study was to determine the sleep quality in these subjects.
A cross sectional study was carried out in 21 adult IGHD subjects, and 21 age- and gender-matched controls. Objective sleep assessment included polygraphic records of the awake, stages NREM [N1 (drowsiness), N2 and N3 (already sleeping)] and REM (R). Subjective evaluation included the Pittsburgh Sleep Quality Index, Insomnia Severity Index, and Epworth Sleepiness Scale.
IGHD subjects showed a reduction in sleep efficiency (p=0.007), total sleep time (p=0.028), duration of N2 and R in minutes (p=0.026 and 0.046, respectively), but had increased duration and percentage of N1 stage (p=0.029 and 0.022 respectively), wake (p=0.007), and wake-time after sleep onset (p=0.017). There was no difference in N3, or in sleep quality questionnaire scores.
Patients with IGHD due to GHRH resistance exhibit objective reduction in sleep quality, with changes in NREM and REM sleep, with no detectable subjective consequences. GHRH resistance seems have a preponderant role over GHD in the sleep quality of these subjects.