Systemic inflammation is associated with MCI and its subtypes: The Sydney memory and aging study

Background/Aims: Raised low-grade systemic inflammation has been associated with dementia, and preliminary studies suggest an association with mild cognitive impairment (MCI). This study examines the relationship between systemic inflammation and MCI subtypes. Methods: We measured the inflammatory markers C-reactive protein, interleukins (IL)-1β, -6, -8, -10 and -12, plasminogen activator inhibitor-1 (PAI-1), serum amyloid A (SAA), tumor necrosis factor-α (TNF-α) and vascular adhesion molecule-1 (VCAM-1) in the Sydney Memory and Ageing Study (MAS) cohort, a longitudinal study of 1,037 Australians aged 70-90 years. Results: After adjusting for possible confounding variables, levels of TNF-α and SAA were higher in participants with MCI compared to cognitively normal individuals, and some sex differences were apparent. Nonamnestic multiple domain MCI was associated with higher levels of IL-1β and IL-12, TNF-α and SAA compared to cognitively normal, amnestic MCI (single and multiple domain) and nonamnestic single domain MCI. PAI-1 levels were higher in cognitively normal and nonamnestic multiple domain MCI than in amnestic multiple domain MCI. Conclusion: Our findings suggest an association between specific inflammatory markers and MCI subtypes, highlight sex differences in the association with MCI, and point to a discrete impact of systemic inflammation on cognition.