Sleep-disordered breathing and oxidative stress in preclinical chronic mountain sickness (excessive erythrocytosis)

Chronic mountain sickness (CMS) is considered to be a loss of ventilatory acclimatization to high altitude (>2500 m) resulting in marked arterial hypoxemia and polycythemia. This case–control study explores the possibility that sleep-disordered breathing (SDB) and associated oxidative stress contribute to the etiology of CMS. Nocturnal respiratory and SaO2SaO2 patterns were measured using standard polysomnography techniques and compared between male high-altitude residents (aged 18–25) with preclinical CMS (excessive erythrocytosis (EE), n = 20) and controls (n = 19). Measures of oxidative stress and antioxidant status included isoprostanes (8-iso-PGF2alpha), superoxide dismutase and ascorbic acid. EE cases had a greater apnea–hypopnea index, a higher frequency of apneas (central and obstructive) and hypopneas during REM sleep, and lower nocturnal SaO2SaO2 compared to controls. 8-iso-PGF2alpha was greater in EE than controls, negatively associated with nocturnal SaO2SaO2, and positively associated with hemoglobin concentration. Mild sleep-disordered breathing and oxidative stress are evident in preclinical CMS, suggesting that the resolution of nocturnal hypoxemia or antioxidant treatment may prevent disease progression.

► We explore the role of sleep-disordered breathing and oxidative stress for polycythemia (CMS). ► Mild sleep-disordered breathing and oxidative stress are evident prior to CMS. ► The resolution of nocturnal hypoxemia or antioxidant therapy may prevent the progression of CMS.