Sleep and quality of life in endocrine diseases

It is well established that a close relationship exists between sleep and hormones of the hypothalamic-pituitary axis. Sleep has an electrophysiological component and an endocrine component, i.e., the distinct patterns of hormone secretion. Both the electrophysiological and the hormonal component interact bi-directional. Sleep-endocrine rhythms are closely interrelated, and sleep is an important regulator of (neuro)endocrine function. The secretion of growth hormone (GH), prolactin (PRL), and thyrotropin (TSH) is markedly increased during sleep, whereas the secretion of adrenocorticotrophic hormone (ACTH) and cortisol is inhibited. Sleep deprivation is associated with decreased GH and PRL secretion, and increased cortisol and TSH secretion. The decrease of GH secretion, which occurs with advancing age, is strongly associated with impaired quality of sleep. Increasing age is associated with increased levels of cortisol, which is significant after age 50 years when sleep is more fragmented and REM sleep declines. GH deficiency in adults (AGHD) is a well-recognized clinical syndrome, which is characterized by abnormal body composition and most notably, impairment of quality of life (QoL). Recent studies on long-term treatment of adult GH-deficient patients have convincingly shown that GH replacement therapy improves QoL in association with a reduction in healthcare utilization. Chronic excess of glucocorticoids, Cushing's syndrome, is associated with sleep disturbances, mood alterations, depression, and impaired QoL. Patients with thyroid disease have sleep disturbances and a significantly reduced health-related QoL.