Inflammatory markers in Alzheimer’s disease and mild cognitive impairment: a meta-analysis and systematic review of 170 studies

Objective Inflammation plays a crucial role in the pathogenesis of mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Our study aimed to analyse previous inconsistent results of inflammatory markers in AD and MCI quantitatively. Methods Studies reporting concentrations of peripheral or cerebrospinal fluid (CSF) markers were included, and eligible data on AD, MCI and control were extracted. Pooled Hedges’s g was adopted to illustrate comparisons, and various confounding factors were used to explore sources of heterogeneity. Results A total of 170 studies were included in the meta-analysis and systematic review, which demonstrated increased peripheral levels of high-sensitivity C reactive protein (Hedges’s g 0.281, p Conclusion Significantly altered levels of inflammatory markers were verified in comparison between AD, MCI and control, supporting the notion that AD and MCI are accompanied by inflammatory responses in both the periphery and CSF.