Obstructive sleep apnoea (OSA) is characterized by overproduction of reactive oxygen species and oxidative stress. The antioxidant enzyme paraoxonase-1 (PON-1) may be useful for monitoring the antioxidant defence systems and the effect of treatments in OSA patients. We investigated, by means of systematic review and meta-analysis, the serum concentrations of PON-1 in OSA patients and non-OSA controls. A literature search was conducted in PubMed, Web of Science, Scopus and Google Scholar databases, from the outset to November 2021, utilizing the terms: "paraoxonase" or "PON" or "paraoxonase-1" or "PON-1" and "obstructive sleep apnoea syndrome" or "OSAS" or "OSA". Eleven studies in 429 OSA patients and 258 non-OSA controls were involved in the meta-analysis. The pooled serum PON-1 concentrations were significantly lower in OSA (standardized mean difference (SMD) = -0.70, 95% CI -1.13 to -0.28; p = 0.001). Despite the extreme between-study heterogeneity, the SMD values were not substantially affected by the sequential omission of individual studies. There was no publication bias. Our systematic review and meta-analysis supports the presence of an impaired antioxidant defence system in OSA, possibly the consequence of intermittent hypoxia. Further studies are required to determine the clinical use of PON-1 measurements for risk stratification and monitoring in OSA patients.
Keywords: obstructive sleep apnoea; oxidant–antioxidant imbalance; paraoxonase-1(PON-1); sleep disorder.