Abdominal Myosteatosis and Cognitive Decline in a Biracial Cohort: Insights from CARDIA Study.

OBJECTIVE

Skeletal muscle fat infiltration (myosteatosis) increases with age and is an emerging risk factor for dementia. We aimed to determine the association between myosteatosis and cognitive decline among middle-aged White and Black Americans.

METHODS

Data were on men (n=1,080; 41.9% Black) and women (n=1,432; 49.0% Black) from the CARDIA study. CT-measured abdominal intermuscular fat (IMAT) volume was assessed at baseline. Cognition was assessed by Digit Symbol Substitution (DSST), Rey Auditory Verbal Learning (RAVLT), and Stroop Test at baseline and 5-year follow-up. Multivariable linear regression was used to assess associations of IMAT with cognitive change.

RESULTS

Participants were aged 50.2 (3.6) years and had IMAT of 2.3 (1.6) cm 3 , 5-year change in DSST of -2.8% (21.8), RAVLT 2.8% (17.5) and Stroop 6.5% (49.5). Greater IMAT was associated with steeper DSST decline (β =-0.52 points per SD, p-value=0.035), but not with Stroop or RAVLT. Stratified by race, greater IMAT predicted DSST decline among White (β =-0.73, p =0.044), but not Black (β =-0.44, p =0.195), participants.

CONCLUSIONS

Abdominal myosteatosis may be a novel risk factor for decline in psychomotor speed, especially in middle-aged Whites. Further research on mechanisms, including metabolic mediators, is warranted to understand myosteatosis's role in mid-life cognitive decline.