The effect of obstructive sleep apnea syndrome on serum S100B and NSE levels: a systematic review and meta-analysis of observational studies

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is a common disorder that is accompanied by structural brain changes. This meta-analysis aimed to evaluate the effect of OSAS on the serum levels of astrocytic protein (S100B) and neuron-specific enolase (NSE) in observational studies. METHODS: A comprehensive search was performed in the PubMed/Medline, Web of Science, Scopus, ScienceDirect, and Cochrane Library databases to assess the serum level of S100B and/or NSE in patients with OSAS and/or controls. The quality of the study was evaluated by the Newcastle-Ottawa Scale (NOS). A random-effects model was performed using RevMan 5.3 with the mean difference (MD) and 95% confidence intervals (CIs). RESULTS: Out of 63 studies found in the mentioned databases and one identified by a manual search, nine studies were included and analyzed in this meta-analysis (three cross-sectional and six case-control studies). The analysis showed that the S100B MD = 53.58 pg/ml, 95%CI: 1.81, 105.35; P = 0.04 and NSE levels MD = 3.78 ng/ml, 95%CI: 2.07, 5.48; P < 0.0001 were significantly higher in patients than the controls. However, there were no significant differences between the S100B MD = -28.00 pg/ml, 95%CI: - 79.48, 23.47; P = 0.29 and NSE levels MD = 0.49 ng/ml, 95%CI: - 0.82, 1.80; P = 0.46. CONCLUSIONS: This meta-analysis found elevated serum S100B and NSE levels in OSAS patients compared to the controls, which suggests that these markers may be used as peripheral indicators of brain damage in OSAS.