Background & objectives: several studies have shown a close relationship between obstructive sleep apnoea (OSA) and dyslipidaemia. This study was designed to clarify the relationship of metabolic dysfunctions in sleep related-breathing disorders (SRBD), including OSA and simple snoring. The end point was to determine the prevalence of hyperlipidaemia and hyperuricaemia in SRBD. Factors contributing to hyperlipidaemia and hyperuricaemia in SRBD were also evaluated.
Methods: Outpatients >20 yr old with complaint of habitual snoring were prospectively enrolled. All patients underwent an overnight polysomnography (PSG) in a sleep laboratory and blood assay after overnight fasting. The factors of gender, age, body mass index (BMI), apnoea-hypopnoea index (AHI), and desaturation index (DI) were recorded in the PsG report. A logistic regression analysis was conducted to investigate the relationship between metabolic dysfunctions and these factors.
Results: Of the 275 patients (88.4% male), 236 (85.8%) were diagnosed with OSA (AHI>5/h). The mean (+/- SD) of age, BMI, AHI, and DI were 44.2 +/- 11.4 yr, 27.4 +/- 4.0 kg/m(2), 37.9 +/- 30.6/h, and 21.2 +/- 23.2/h, respectively. The overall prevalence of hypercholesterolaemia, hypertriglyceridaemia, and hyperuricaemia in this study was 61.1, 55.3, and 25.8 per cent, respectively. Logistic regression analysis revealed that DI was a significant independent factors contributing to hypercholesterolaemia [odds ratio (OR)=1.016, P=0.010, 95% confidence interval (CI)=1.004-1.028] and hypertriglyceridaemia (OR=1.021, P=0.002, 95% CI=1.008-1.034).
Interpretation & conclusions: The data of the present study support a high prevalence of hyperlipidaemia in SRBD. DI may be a determining factor contributing to hyperlipidaemia in SRDB. Underdiagnosis of hyperlipidaemia in SRBD is a critical problem.