A systematic review with meta-analysis to assess Alzheimer's disease biomarkers in adults with or without obstructive sleep apnoea

Abstract

Introduction > The aim was to design a meta-analysis evaluating the positron emission tomography (PET) uptake and cerebrospinal fluid (CSF), circulating levels of amyloid-beta (A beta), and tau proteins OSA group versus control group, as well as the association of these biomarkers with the severity of OSA.Material and methods > Four databases were searched until April 17, 2023, without any restrictions. The effect sizes were the standardized mean difference (SMD) along with a 95 confidence interval (CI).Results > A total of 21 articles were entered into the meta-analysis. The pooled SMDs of the CSF levels in OSA adults compared to controls were: -0.82 (P = 0.004) for A beta 42, -1.13 (P < 0.001) for A beta 40, 0.17 (P = 0.23) for p-tau, 0.04 (P = 0.65) for t-tau, 0.08 (P = 0.89) for A beta 42/A beta 40 ratio, and 0.81 (P = 0.001) for t-tau/A beta 42 ratio. The pooled SMD for the PET uptake of A beta burden in OSA adults compared to controls was 0.30 (P = 0.03). The pooled SMDs of the circulating levels in OSA adults compared to controls were: 0.67 (P = 0.002) for A beta 42, 0.11 (P = 0.82) for A beta 40, 0.35 (P = 0.06) for p-tau, and 1.41(P = 0.005) for t-tau. The pooled SMDs for levels of A342, A340, total A3, p-tau, t-tau, and A342/A340 ratio in severe OSA adults compared to mild/moderate OSA adults were -0.15 (P = 0.33), 0.25 (P = 35), 0.04 (P = 87), -2.53 (P = 0.24), -0.24 (P = 0.52), and -0.28 (P = 0.30), respectively.Conclusions > The results indicated that CSF levels of A beta 42 and A beta 40 in OSA adults were significantly lower, but the CSF level of t-tau/A beta 42 ratio and PET A beta burden uptake in OSA adults significantly were higher than in controls.