Abstract
BackgroundObstructive sleep apnea (OSA) is characterized by repeated episodes of obstruction of the upper airway. Numerous studies have indicated a relationship between OSA and metabolic syndrome (MS), but the results remain debatable. We aimed to perform a systematic review and meta-analysis to evaluate the association between OSA and MS.MethodsWe searched electronic databases (PubMed, EMBASE, and ISO Web of Knowledge) up to September 2014 with English-language restriction. Cross-sectional, case–control, and cohort studies in which the presence of OSA was assessed by objective measurements, the exposure of interest was OSA, and the outcome of interest was the presence (or incidence) of MS were included. The adjusted odds ratios (ORs) (or relative risk) and 95 % confidence intervals (CIs) were extracted and pooled. Sensitivity analyses were conducted, and heterogeneity and publication bias were assessed.ResultsOverall, 15 cross-sectional (2456 patients with OSA and 1705 subjects without OSA), five case–control (1156 OSA patients and 404 controls), and no cohort studies were included. The pooled ORs of MS in individuals with OSA for cross-sectional and case–control studies were 2.87 (95 % CI: 2.41–3.42) and 2.56 (95 % CI: 1.98–3.31), respectively. There was clinically unimportant (I2 = 20 %) and moderate (I2 = 35 %) between-study heterogeneity of the analysis. The pooled crude ORs of MS in individuals with mild and moderate-to-severe OSA was 2.39 (95 % CI: 1.65–3.46) and 3.45 (95 % CI: 2.33–5.12), respectively, and there was substantial heterogeneity in the meta-analyses (I2 = 53 % and I2 = 63 %, respectively). However, no evidence of publication bias was detected.ConclusionsOSA is shown to be associated with MS, although causality between these two factors has not been demonstrated yet. Future cohort and randomized controlled studies are needed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0102-3) contains supplementary material, which is available to authorized users.
Highlights
Obstructive sleep apnea (OSA) is characterized by repeated episodes of obstruction of the upper airway
The fact that no metaanalysis has been conducted on this relationship, we aimed to perform a systematic review and meta-analysis to evaluate the association between OSA and metabolic syndrome (MS)
All of the studies used the apnea–hypopnea index (AHI) based on an overnight PSG to diagnose OSA, whereas the AHI thresholds differed between studies
Summary
Obstructive sleep apnea (OSA) is characterized by repeated episodes of obstruction of the upper airway. Numerous studies have indicated a relationship between OSA and metabolic syndrome (MS), but the results remain debatable. Obstructive sleep apnea (OSA) is a condition in which there is repetitive obstruction of the upper airway during sleep, resulting in hypopnea (reduced airflow during sleep) or apnea (complete cessation of airflow during sleep) [1, 2]. Patients with OSA may experience symptoms, including loud souring, frequent arousals, sleep fragmentation, and daytime sleepiness, which characterize. Numerous studies have indicated a relationship between OSA and MS, but the results remain debatable [16]. Coughlin et al found that OSA was independently associated with an increased risk of MS, irrespective of age and body mass index (BMI) [17]. Papanas et al showed that the strong association between the presence of OSA and MS became non-significant when BMI was considered [18]
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