The Endocrine Impact of Obstructive Sleep Apnea: Mechanisms, Hormonal Dysregulation, and Emerging Therapeutic Strategies

Abstract

Obstructive sleep apnea is widely recognized for its cardiovascular and pulmonary complications, but contemporary evidence has increasingly illuminated its multifaceted neuroendocrine consequences. This review synthesizes evidence from landmark physiological investigations alongside recent genetic epidemiology, metabolomic analyses, and randomized clinical trials. Recurrent pharyngeal collapse during sleep generates two core triggers: intermittent hypoxemia and cortical sleep fragmentation. These triggers drive sustained sympathetic hypertonicity, oxidative stress, and systemic inflammation, precipitating dysfunction across the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-gonadal, and hypothalamic-pituitary-thyroid axes, while also inducing profound peripheral insulin and leptin resistance. Chronic nocturnal elevation of cortisol promotes visceral fat accumulation and hepatic glucose production, establishing a feed-forward loop in which cortisol- driven pharyngeal fat deposition further increases upper airway collapsibility. Loss of slow-wave and rapid eye movement sleep blunts pulsatile luteinizing hormone secretion and Leydig cell steroidogenesis, producing functional hypogonadism in affected men, while sleep-disordered breathing contributes to reproductive and metabolic dysfunction in women. Bidirectional Mendelian randomization studies have established that primary thyroid hormone deficiency causally elevates the risk of obstructive sleep apnea, whereas genetic liability to obstructive sleep apnea does not causally produce thyroid failure. Intermittent hypoxia independently impairs glycemic regulation through catecholamine-driven hepatic glucose output, downregulation of skeletal muscle glucose transporters, and oxidative injury to pancreatic beta cells; hypoxic burden during rapid eye movement sleep appears to be the strongest independent predictor of systemic insulin resistance. Appetite regulation is likewise disrupted, with paradoxical elevation of circulating leptin alongside functional leptin resistance and heightened ghrelin-driven orexigenic drive. Continuous positive airway pressure mitigates sympathetic tone and modestly enhances metabolic parameters, but because it is essentially weight-neutral its effect on systemic obesity and long-term endocrine restoration is limited. The introduction of dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonists provides a viable metabolic mechanism to reduce disease severity and improve endocrine function, with phase 3 trial data showing substantial reductions in the apnea-hypopnea index alongside weight loss. Obstructive sleep apnea therefore exerts systemic endocrine disruption across central and peripheral axes, and comprehensive management requires proactive bidirectional screening between sleep medicine, internal medicine, and endocrinology clinics.