Obstructive sleep apnea is associated with fatty liver index, the index of nonalcoholic fatty liver disease.

BACKGROUND AND OBJECTIVES: The relationship between obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD) is gaining increased attention. The aim of the present study was to examine the relationship of OSA with NAFLD defined by an elevated fatty liver index (FLI). MATERIALS AND METHODS: A total of 319 consecutive patients who underwent standard polysomnography were enrolled. Fasting blood samples were obtained from all patients for biological profile measurements, and demographic data were collected. Values of FLI were determined and assessed as predictors of the presence of NAFLD, as measured by ultrasound. The discriminative ability of FLI was estimated on the basis of the area under the receiver operator characteristic curve. RESULTS: An FLI of 60 achieved the highest diagnostic accuracy and yielded an area under the receiver operator characteristic curve of 0.822 (95% confidence interval: 0.729-0.916) in the detection of NAFLD. Patients with an FLI of 60 or higher had a significantly lower lowest O2 saturation (73 vs. 83%, P<0.001), a lower mean nocturnal oxygen saturation (93 vs. 95%, P<0.001), a higher apnea-hypopnea index (39.7 vs. 18.4, P<0.001), a higher oxygen desaturation index (39 vs. 10.6, P<0.001), and a higher percentage of sleep time spent with SpO2 less than 90% (4.63 vs. 0.92%, P<0.001) compared with those with FLI less than 60. In multivariate analysis, the presence of OSA was independently associated with elevated FLI after adjusting for confounding factors (odds ratio: 5.141, 95% confidence interval: 1.414-18.696, P=0.013). CONCLUSION: Our results suggest a positive association between the severity of OSA and NAFLD defined by an elevated FLI, which may serve as a good biomarker for detecting NAFLD in OSA patients.

The relationship between excessive daytime sleepiness and metabolic syndrome in severe obstructive sleep apnea syndrome.

BACKGROUND: Excessive daytime sleepiness (EDS), which is commonly considered a cardinal sign of obstructive sleep apnea (OSA), may lead to an increased rate of metabolic syndrome (MetS), and be an independent risk factor for cardiovascular morbidity and mortality. The aim of this cross-sectional study was to examine the role of EDS in MetS and its components by researching severe OSA patients. METHODS: The records of 175 consecutive patients who underwent standard polysomnography and diagnosed severe OSA were included. Subjective daytime sleepiness was assessed using the Epworth sleepiness scale (ESS). Fasting glucose, lipids, insulin and polysomnography parameters were measured. A metabolic score was counted as the total number of the positive diagnostic criteria of MetS for each subject, which indicated the level of metabolic disorder. RESULTS: The prevalence of central obesity, hypertriglyceridemia, low high density lipoprotein-cholesterol and MetS (78.2% vs 28.6%) was significantly higher among EDS group compared with control group. Compared with non-EDS patients, patients with EDS showed significantly higher metabolic score (3.22 ± 0.94 vs 1.96 ± 1.06). After adjustment for confounders, ESS score, log insulin and age significantly predicted the metabolic score (ß = 0.567, P = 0.000; ß = 0.197, P = 0.001 and ß = 0.118, P = 0.048, respectively). CONCLUSION: EDS was independently correlated with the sum of metabolic components in severe OSA patients. Our study suggested that EDS might be a potentially useful clinical marker to identify patients with severe OSA at risk of MetS.

Obstructive sleep apnea syndrome is associated with metabolic syndrome and inflammation.

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular morbidity and mortality. However, the underlying mechanism is unclear. In this cross-sectional study, we investigated the influence of OSA on metabolic syndrome (MetS) and inflammation, which were considered as cardiovascular risks. A total of 144 consecutive male patients who underwent standard polysomnography were enrolled. Fasting blood samples were obtained from all patients for glucose, high-sensitivity C-reactive protein (hs-CRP) and lipids measurement. A metabolic score was established as the total number of the positive diagnostic criteria of metabolic syndrome for each patient. Systolic blood pressure, diastolic blood pressure, fasting glucose, hs-CRP and metabolic score significantly increased with the aggravation of OSA severity. Metabolic score increased from 1.74 ± 1.20 to 2.89 ± 0.99 with OSA severity (p = 0.000). hs-CRP increased from 0.68 (0.43-1.10) to 1.44 (0.62-4.02) mg/L with OSA severity (p = 0.002). After adjustment for confounders, apnea-hypopnea index and body mass index (BMI) were the major contributing factors for metabolic score (ß = 0.257, p = 0.003 and ß = 0.344, p = 0.000, respectively), lowest O2 saturation and BMI were the independent predictors of hs-CRP (ß = -0.255, p = 0.003 and ß = 0.295, p = 0.001, respectively). OSA is independently associated with sum of metabolic components and hs-CRP.