Featured ArticleMicroinfarcts are common and strongly related to dementia in the oldest-old: The 90+ study

•Microinfarct pathology is common in the oldest-old.•Microinfarcts are strongly associated with dementia.•Microinfarcts contribute independently and similarly in magnitude to dementia as tangle pathology.•Only microinfarcts in cortical regions (other than occipital) are associated with dementia.

IntroductionWe estimated the prevalence of microinfarcts and their association with dementia in a cohort of oldest-old participants.MethodsParticipants were from The 90+ Study, a population-based study of people 90 years and older. Dementia diagnoses were assigned postmortem during a consensus conference. Microinfarcts were evaluated in six brain regions.ResultsAt death, the 213 participants were on average 97 years old, 69% were women, and 52% had dementia. Of the participants, 51% had microinfarcts and 17% had 3+ microinfarcts. The odds ratio (OR) for dementia was similar for 3+ microinfarcts (OR = 4.75, P < .01) and tangle stage V-VI (OR = 4.70, P < .001). Only microinfarcts in cortical regions (other than occipital) were associated to dementia.DiscussionIn this oldest-old cohort, microinfarcts are common and contribute independently and similarly in magnitude to dementia as tangles. As risk factors for microinfarcts and other dementing pathologies are likely to differ, identifying these factors is crucial to developing prevention strategies for dementia in the oldest-old.