Multimorbidity burden and dementia risk in older adults: The role of inflammation and genetics

INTRODUCTION: We investigate dementia risk in older adults with different disease patterns and explore the role of inflammation and apolipoprotein E (APOE) genotype. METHODS: A total of 2,478 dementia‐free participants with two or more chronic diseases (ie, multimorbidity) part of the Swedish National study on Aging and Care in Kungsholmen (SNAC‐K) were grouped according to their multimorbidity patterns and followed to detect clinical dementia. The potential modifier effect of C‐reactive protein (CRP) and apolipoprotein E (APOE) genotype was tested through stratified analyses. RESULTS: People with neuropsychiatric, cardiovascular, and sensory impairment/cancer multimorbidity had increased hazards for dementia compared to the unspecific (Hazard ration (HR) 1.66, 95% confidence interval [CI] 1.13‐2.42; 1.61, 95% CI 1.17‐2.29; 1.32, 95% CI 1.10‐1.71, respectively). Despite the lack of statistically significant interaction, high CRP increased dementia risk within these patterns, and being APOE ε4 carriers heightened dementia risk for neuropsychiatric and cardiovascular multimorbidity. DISCUSSION: Individuals with neuropsychiatric, cardiovascular, and sensory impairment/cancer patterns are at increased risk for dementia and APOE ε4, and inflammation may further increase the risk. Identifying such high‐risk groups might allow tailored interventions for dementia prevention.