Association between mean corpuscular volume and cognitive function in community-dwelling older adults: An 8-year...

Larger mean corpuscular volume (MCV) may indicate impaired oxygen and nutrient delivery to the brain, and could be associated with cognitive impairment, yet longitudinal evidence remains limited. This study investigated this association in community-dwelling older adults.

This prospective cohort study (2011-2022) was from the Taiwan Initiative for Geriatric Epidemiological Research at baseline with four biennial follow-ups. Global cognition was assessed longitudinally using the Montreal Cognitive Assessment, Taiwanese version, and domain-specific cognition via a battery of neuropsychiatric tests. Red cell distribution width (RDW), hemoglobin, platelet, and vitamin B12 were also collected. Generalized linear mixed models were utilized to analyze the association between baseline MCV and cognition adjusting for covariates.

A total of 530 non-demented participants (mean age 72.7 ± 5.3 years, range 65-89; 247 men and 283 women) were included. MCV was non-linearly associated with cognition. Larger baseline MCV (>93.0 fL) was significantly associated with poor memory (immediate free recall, delayed free recall, and delayed theme recall: βˆ = -0.028 to -0.041) and attention (digit span forward: βˆ = -0.028) over time, particularly in those with high platelet counts (> 230 × 10³/μL), high hemoglobin, and in men. A significant interaction between MCV and age on global cognition (p_interaction = 0.04) was observed.

Elevated baseline MCV was associated with poor cognition, especially in memory and attention domains, over time. Future longitudinal studies are warranted to confirm this temporal relationship.