Abdominal myosteatosis is associated with lower processing speed in a multiethnic cohort of older adults.

Background: Prior research linking myosteatosis with cognition in older adults has been conducted in relatively homogenous populations with narrow age ranges. We evaluated if abdominal myosteatosis was associated with processing speed in a multiethnic cohort of middle aged and older adults.

Methods: The analytical sample included 1,268 adults (46-86 years old, mean 63±9 years, 53% female of 41% White, 20% Black, 14% Chinese, and 25% Hispanic), a subset from the Multi-Ethnic Study of Atherosclerosis (MESA). Bivariate analyses were performed between abdominal computed tomography derived muscle densities (a myosteatosis measure) at year 3 with Digit Symbol Coding (DSC) with cytokines. Multivariable models were first adjusted for demographics, education, and general cognition, and further adjusted for other known predictors of dementia: -4, physical activity, diabetes, cholesterol, smoking, and blood pressure. We further assessed whether central adiposity, general adiposity, and cytokines modified this association. We tested interactions by ethnicity, sex, and age.

Results: Rectus abdominis myosteatosis was significantly associated with worse DSC (B= -0.247, 95% CI: 0.098,0.396, p=0.001) independent of demographics, education, general cognition, and dementia risk factors. Adjustment for central adiposity, and cytokines did not attenuate the associations. Tests for interactions by ethnicity, sex, and age were not statistically significant.

Conclusions: Rectus abdominis myosteatosis is associated with worse processing speed in this middle and older aged multiethnic population of men and women, independent of other known predictors of cognition. Longitudinal studies should assess the interplay of myosteatosis with other markers of adiposity, inflammation, and circulating mediators and their combined impact on processing speed.

Highlights: Abdominal myosteatosis correlated with lower cognitive processing speed in older adults.Myosteatosis links muscle density to cognitive function beyond dementia risk factors.Pro-inflammatory cytokines do not mediate the muscle-cognition association.Ethnicity, sex, and adiposity measures do not modify myosteatosis-cognition links.Abdominal CT scans could serve as diagnostic tools for cognitive health insights.