Abstract
BackgroundObstructive sleep apnea syndrome (OSAS) is associated with various adipokines. Leptin, a common adipokine, has attracted considerable attention of many researchers in recent years. So far, there has been little agreement on whether blood leptin levels differ in patients with OSAS. Thus, this meta-analysis examined the relationship between serum/plasma leptin levels and the occurrence of OSAS.MethodWanFang, Embase, CNKI, Medline, SinoMed, Web of Science, and PubMed were searched for articles before March 30, 2021, with no language limitations. STATA version 11.0 and R software version 3.6.1 were used to analyze the obtained data. The weighted mean difference and correlation coefficients were used as the main effect sizes with a random-effects model and a fixed-effects model, respectively. Trial sequential analysis was conducted using dedicated software.ResultScreening of 34 publications identified 45 studies that met the inclusion criteria of this meta-analysis and meta-regression. Our results suggested that plasma/serum leptin levels were remarkably higher in individuals with OSAS than in healthy individuals. Subgroup analyses were performed based on OSAS severity, ethnicity, age, body mass index, assay type, and sample source. The serum and plasma leptin levels were increased in nearly all OSAS subgroups compared to those in the corresponding control groups. Meta-regression analysis indicated that age, BMI, severity, assay approaches, study design, PSG type and ethnicity did not have independent effect on leptin levels. Furthermore, a positive relationship between the serum/plasma leptin level and apnea-hypopnea index (AHI) was found in the meta-analysis. The results of the trial sequential analysis suggested that the enrolled studies surpassed the required information size, confirming that our study findings were reliable.ConclusionOur study results demonstrate that OSAS patients have higher leptin levels in serum/plasma compared to controls, and the serum/plasma leptin level is positively correlated with AHI, especially in adults.
Highlights
Obstructive sleep apnea syndrome (OSAS) is a multifactorial disease with complex pathophysiology that manifests as upper airway obstruction, chronic nocturnal intermittent hypoxia, and fragmented sleep (1)
We retrieved the full texts of the articles and excluded several full texts for following reasons: five were reviews; two were letter to editor studies; four had no control or control group was selected as apnea-hypopnea index (AHI)>5 events/h in adults and AHI>1 events/h in children; six had no relevant data; four reported polymorphisms of leptin; 2 reported animal experiments;[3] reported patients with OSAS
Eleven studies provided data on the plasma leptin levels in OSA patients diagnosed by lab PSG, and the results reveal that the plasma leptin levels were higher in these OSA patients than in the controls (WMD=4.32 ng/ml, 95% CI=2.73,5.91, P
Summary
Obstructive sleep apnea syndrome (OSAS) is a multifactorial disease with complex pathophysiology that manifests as upper airway obstruction, chronic nocturnal intermittent hypoxia, and fragmented sleep (1). Kapusuz et al (11) showed that patients with OSAS have higher circulating levels of leptin compared to controls. The association between OSAS and serum/plasma leptin levels is intricate and multidirectional because obesity alone can affect leptin levels. Sánchez et al (12) reported that obese individuals without OSAS display higher circulating levels of leptin, and sleep apnea is not a decisive factor for leptin levels. Some studies that directly examined the relationship between OSAS and leptin serum/plasma levels have been recently published, yet with controversial conclusions (14, 15). There has been little agreement on whether blood leptin levels differ in patients with OSAS. This meta-analysis examined the relationship between serum/plasma leptin levels and the occurrence of OSAS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
