Sleep patterns in growth hormone deficient children and age-matched controls: developmental considerations

Ten patients with isolated growth hormone (GH) deficiency and 13 age-matched normal controls were studied. All patients were below the 3rd percentile in height and weight. All but 1 subject were studied for 3 or 4 consecutive nights in the sleep laboratory which included monitoring of the EEG, EOG, EMG, and EKG. GH samples were taken during sleep in 6 of the 10 patients. There were no significant differences in the slow-wave sleep (SWS) parameter between the 2 groups, nor was there any difference when all growth hormone patients were compared to controls. The age group comparisons for the percent of rapid eye movement (REM) sleep parameter revealed a significant difference between GH and controls for the youngest group only (p less than 0.05). Similar results were obtained when the GH subjects were grouped according to bone age. A significant decline in SWS was found with increasing chronological age (p less than 0.02), while the REM parameter did not show any significant changes across age categories. None of the patients showed a sleep-related peak in GH secretion. These data are not compatible with the hypothesis of a monotonic relationship between SWS and GH secretion.