Association between lipid peroxidation and inflammation in obstructive sleep apnoea

In the present study, the authors examined the relationship between lipid peroxidation and inflammation in patients with obstructive sleep apnoea (OSA). A total of 40 obese patients with OSA were studied, along with 18 obese and 12 lean subjects without OSA. Overnight excretion of 8-isoprostane in urine and serum levels of high-sensitivity C-reactive protein (hsCRP) were measured. In addition, the effects of 3 months' treatment with nasal continuous positive airway pressure (nCPAP) were studied in 20 obese patients with moderate-to-severe OSA. Overnight urinary excretion of 8-isoprostane and serum levels of hsCRP were significantly higher in patients with moderate-to-severe OSA compared with patients with mild OSA and obese or lean subjects without OSA. Overnight urinary excretion of 8-isoprostane significantly correlated with apnoea-hypopnoea index, duration of hypoxia during sleep, body mass index, and serum levels of hsCRP in patients with OSA. The severity of OSA was an independent factor predicting the urinary excretion of 8-isoprostane. nCPAP significantly decreased urinary excretion of 8-isoprostane and serum levels of hsCRP. In conclusion, these results suggest that both obstructive sleep apnoea severity and obesity can independently contribute to elevations in urinary excretion of 8-isoprostane. Therefore, obstructive sleep apnoea may increase the risks of cardiovascular morbidity in obese patients.