Autoimmune antibodies and systemic inflammatory markers are prevalent and associated with cognition in individuals aged 90+

BackgroundWhile recent studies have found associations between markers of autoimmunity/inflammation and cognitive performance in individuals aged 60-90, these findings remain unexplored in individuals aged 90 and above.ObjectiveTo examine the prevalence of autoimmune antibodies and raised inflammatory markers and their associations with cognition in participants aged 90 + .MethodsWe included participants with serological testing from The 90+ Study, a community-based longitudinal study in southern California. For measures of autoimmunity, we evaluated antinuclear, antineutrophil cytoplasmic (ANCA), rheumatoid factor, double stranded DNA, antithyroglobulin, and thyroid peroxidase antibodies. For inflammatory markers, we examined interleukin-6 (IL-6) and erythrocyte sedimentation rate (ESR). To examine the relationship between autoimmune antibodies and inflammatory markers with cognitive performance, we ran linear mixed effects models.ResultsAmong 201 participants (mean age 94.8 years, 56.7% female, 93.5% white, and 4.5% with rheumatologic illness), autoimmune antibodies were positive in 70.2%. Also, among 142 participants with test results, elevated inflammatory markers were detected in 76.8%. Linear mixed effects model analyses revealed an association between higher levels of ANCA (<i>p</i> = 0.04), IL-6 (<i>p</i> = 0.01), and ESR (<i>p</i> = 0.01) and lower global cognitive scores. In a subset of participants with amyloid PET (<i>n</i> = 173), results remained significant even after accounting for amyloid burden.ConclusionsAutoimmune antibodies and raised inflammatory markers were highly prevalent in a community cohort of individuals aged 90 + . Our results suggest that increased prevalence of autoimmunity and inflammation might be associated with worse cognitive performance in this age group, independent of amyloid.