Prevalence of mild cognitive impairment is higher in men

TLDR

The study examined the prevalence of mild cognitive impairment among Olmsted County residents aged 70–89 using in‑person evaluations and established criteria. Researchers assessed a random, age‑ and sex‑stratified sample of 70–89‑year‑olds with the Clinical Dementia Rating Scale, neurologic examination, and neuropsychological testing of memory, executive function, language, and visuospatial skills, with diagnoses adjudicated by a panel. Among 1,969 dementia‑free participants, 16% had MCI (11% amnestic, 5% non‑amnestic); prevalence rose with age, was higher in men (OR 1.54), in never‑married individuals, and in APOE ε3ε4/ε4ε4 carriers, and declined with years of education, with amnestic MCI being the most common subtype.

Abstract

<b>Objective:</b> We investigated the prevalence of mild cognitive impairment (MCI) in Olmsted County, MN, using in-person evaluations and published criteria. <b>Methods:</b> We evaluated an age- and sex-stratified random sample of Olmsted County residents who were 70–89 years old on October 1, 2004, using the Clinical Dementia Rating Scale, a neurologic evaluation, and neuropsychological testing to assess 4 cognitive domains: memory, executive function, language, and visuospatial skills. Information for each participant was reviewed by an adjudication panel and a diagnosis of normal cognition, MCI, or dementia was made using published criteria. <b>Results:</b> Among 1,969 subjects without dementia, 329 subjects had MCI, with a prevalence of 16.0% (95% confidence interval [CI] 14.4–17.5) for any MCI, 11.1% (95% CI 9.8–12.3) for amnestic MCI, and 4.9% (95% CI 4.0–5.8) for nonamnestic MCI. The prevalence of MCI increased with age and was higher in men. The prevalence odds ratio (OR) in men was 1.54 (95% CI 1.21–1.96; adjusted for age, education, and nonparticipation). The prevalence was also higher in subjects who never married and in subjects with an <i>APOE</i> ε3ε4 or ε4ε4 genotype. MCI prevalence decreased with increasing number of years of education (<i>p</i> for linear trend &lt;0.0001). <b>Conclusions:</b> Our study suggests that approximately 16% of elderly subjects free of dementia are affected by MCI, and amnestic MCI is the most common type. The higher prevalence of MCI in men may suggest that women transition from normal cognition directly to dementia at a later age but more abruptly.