Influence of obstructive sleep apnea on fatty liver disease: role of chronic intermittent hypoxia.

BACKGROUND Currently the common pathogenetic mechanisms in nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA) are gaining increased attention. The aim of this study is to find out the influence of chronic intermittent hypoxemia and OSA related parameters to the severity of NAFLD. METHODS We examined the liver functions tests and ultrasonographic data of liver as well as markers of OSA severity (apnea-hypopnea index [AHI], oxygen desaturation index, minimum oxygen saturation, percentage of time spent with S(pO(2)) < 90%) of 106 subjects. RESULTS Fatty liver disease was diagnosed in 71 subjects (group 1), and the remaining 35 subjects were taken as controls (group 2). The prevalence of OSA was 71.2% versus 35.7% for group 1 and 2, respectively (P < .001). As NAFLD severity increased from mild to severe form, mean AHI and oxygen desaturation index values also increased significantly. Our multivariate analysis showed that AHI, oxygen desaturation index, lowest desaturation values, and percentage of sleep duration with S(pO(2)) < 90% were independent predictors of NAFLD after adjustment for BMI, weight, and insulin resistance. Furthermore, the most correlated parameter for the severity of NAFLD was found as the duration of hypoxia during sleep. CONCLUSIONS The prevalence of NAFLD was higher in patients with severe OSA, suggesting a role for nocturnal hypoxemia in the pathogenesis of fatty liver disease.