LAUSR

Key Points Question What is the relevance of types of blood leukocytes in Alzheimer disease (AD)? Findings In this cohort study of 101 582 individuals in the Danish general population, low baseline blood monocyte counts were associated with increased AD risk. In a mendelian randomization framework using the most powerful genomic data sets, genetically determined low monocyte counts were also associated with increased AD risk, an association independent of other types of blood leukocytes. Meaning The findings of this study suggest that the observational and genetic association observed between low monocyte counts and increased risk of AD highlights a possible role of the innate immune system in AD pathogenesis.