{Reference Type}: Journal Article
{Title}: Plasma IL-6 levels and their association with brain health and dementia risk: A population-based cohort study.
{Author}: Zhao Z;Zhang J;Wu Y;Xie M;Tao S;Lv Q;Wang Q;
{Journal}: Brain Behav Immun
{Volume}: 120
{Issue}: 0
{Year}: 2024 Aug 17
{Factor}: 19.227
{DOI}: 10.1016/j.bbi.2024.06.014
{Abstract}: <B>BACKGROUND: </B>Recent studies have associated immune abnormalities with dementia. IL-6 is a crucial cytokine in inflammatory responses, and recent evidence has linked elevated IL-6 levels to changes in brain structure and cognitive decline. However, the connection between IL-6 levels, cognition, brain volumes, and dementia risk requires exploration in large prospective cohorts.<BR><B>METHODS: </B>This study utilized a longitudinal cohort from the UK Biobank to analyze the correlation between IL-6 expression levels, cognitive performance, and cortical and subcortical brain volumes through linear regression. Additionally, we assessed the association between IL-6 levels and long-term dementia risk using Cox regression analysis. We also used one-sample Mendelian randomization to analyze the impact of genetic predisposition of dementia on elevated IL-6 levels.<BR><B>RESULTS: </B>A total of 50,864 participants were included in this study, with 1,391 new cases of all-cause dementia identified. Higher plasma IL-6 levels are associated with cortical and subcortical atrophy in regions such as the fusiform, thalamus proper, hippocampus, and larger ventricle volumes. IL-6 levels are negatively associated with cognitive performance in pair matching, numeric memory, prospective memory, and reaction time tests. Furthermore, elevated IL-6 levels are linked to a 23-35 % increased risk of all-cause dementia over an average follow-up period of 13.2 years. The one-sample Mendelian randomization analysis did not show associations between the genetic predisposition of dementia and elevated IL-6 levels.<BR><B>CONCLUSIONS: </B>Increased IL-6 levels are associated with worse cognition, brain atrophy, and a heightened risk of all-cause dementia. Our study highlights the need to focus on the role of peripheral IL-6 levels in managing brain health and dementia risk.