Inflammatory Markers in Mild Cognitive Impairment: A Meta-Analysis

Reports of elevated inflammatory markers in mild cognitive impairment (MCI) suggest that inflammation may be a potential early marker of the neurodegenerative cascade associated with Alzheimer's disease (AD). The aim of this study was to quantitatively summarize the data on peripheral blood concentrations of inflammatory factors in patients with MCI compared to controls. Mean (+/- SD) blood concentrations of inflammatory factors for MCI and control subjects were extracted from original English language peer-reviewed studies for meta-analysis. Twenty-two studies measuring concentrations of cytokines, chemokines, acute phase reactant proteins, immunoglobulins, intercellular adhesion molecules, and fibrinogen were included. No significant differences in inflammatory factors studied were found between subjects with MCI and healthy controls. These findings do not support the involvement of inflammatory markers at the MCI stage of cognitive decline although significant heterogeneity was observed in some comparisons. It remains to be established whether inflammation may predict increased rate of conversion to dementia.