Association between brain-derived neurotrophic factor levels and obstructive sleep apnea: a systematic review and meta-analysis

Purpose: Chronic intermittent hypoxia associated with obstructive sleep apnea (OSA) can affect neurons and glial cells, leading to cell stress and damage, and changes in brain-derived neurotrophic factor (BDNF) levels. This study investigated the relation between BDNF, OSA, and continuous positive airway pressure (CPAP) — the standard of care in patients with OSA. Methods: Five databases were searched for studies that evaluated BDNF serum and/or plasma levels in patients with OSA and controls or publications assessing the effect of CPAP treatment on BDNF levels. We used standardized mean difference (SMD) with its 95% confidence interval (CI) comparison between patients with OSA and controls. Results: Ten studies were included in our study assessing the relation between BDNF levels, OSA, and CPAP treatment. Five studies of BDNF levels in OSA compared to controls showed no significant difference (SMD = − 0.52, 95% CI [− 1.93; 0.89], p-value = 0.47). No statistically significant difference was found between CPAP treatment in patients with OSA and BDNF levels (SMD = − 0.78, 95% CI [− 1.77; 0.21], p-value = 0.12). Conclusion: BDNF peripheral levels are not significantly altered in OSA or by its related treatment, preventing its use as a biomarker.