Sarcopenia modifies the association between diet quality and cognitive function in community-dwelling older people: a cross-sectional study.

BACKGROUND

Sarcopenia and cognitive impairment are common age-related conditions that severely affect older adults' quality of life. Diet quality, a modifiable factor, has been associated with muscle health and cognitive function, suggesting a potential interaction between sarcopenia, diet, and cognition. However, this relationship remains underexplored.

METHODS

This cross-sectional study included 2,572 community-dwelling adults aged 60 + from Shanghai, China. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), sarcopenia was diagnosed based on the Asian Working Group for Sarcopenia 2019 guidelines, and diet quality was evaluated with the modified Chinese Healthy Eating Index (CHEI). Multivariate regression models, along with interaction, mediation, and subgroup analyses, were applied to examine these associations.

RESULTS

After adjustments, general sarcopenia and non-sarcopenia were associated with higher MoCA scores (β = 1.25, P = 0.006; β = 2.17, P < 0.001), compared to severe sarcopenia. Diet quality (CHEI scores) was positively associated with MoCA (β = 0.05, P < 0.001). Interaction analysis showed that the positive association between diet quality and MoCA score was attenuated with increasing sarcopenia severity (P for interaction < 0.05). Subgroup analysis revealed that age, body mass index, and education modified the sarcopenia-cognition association, whereas living status and cardiovascular disease history modified the diet-cognition association (all P for interaction < 0.05). Mediation analysis found no significant indirect associations.

CONCLUSION

This study highlights an interaction between diet quality and sarcopenia in relation to cognitive function. Higher diet quality was associated with better cognitive performance, but this association appeared weaker among individuals with more severe sarcopenia. Given the cross-sectional design, causality and directionality cannot be inferred; longitudinal and interventional studies are warranted to confirm these findings and inform prevention strategies.