Cognitive function and gait speed in older adults: Findings from the ELSI-Brazil study.

BACKGROUND Although cognitive impairment is associated with adverse outcomes, evidence on its relationship with gait speed across specific cognitive domains remains limited, particularly in middle-income countries.

OBJECTIVE To investigate the association between global and domain-specific cognitive function and gait speed in Brazilian older adults.

METHODS This cross-sectional study included 6940 participants from the Brazilian Longitudinal Study of Aging (ELSI-Brazil). Gait speed was assessed with standardized z-scores and classified as "normal" or "slower". Global cognitive function and specific domains (immediate and delayed memory, verbal fluency, and temporal orientation) were similarly standardized and categorized as "normal" or "impaired". Associations between cognition and gait speed were estimated using crude and adjusted Poisson regression models. Interaction analyses with sociodemographic, behavioral, and health-related variables were performed.

RESULTS Participants were mostly female (52.8%) aged 50-59 years (51.0%). Slower gait speed was observed in 10.1% (95% CI: 8.3, 12.1), while impaired global cognition occurred in 12.5% (95% CI: 11.1, 14.0). In the adjusted models, global cognitive impairment was associated with a higher prevalence of slower gait speed (PR: 1.63; 95% CI: 1.30, 2.04). Verbal fluency (PR: 1.80; 95% CI: 1.45, 2.24) and delayed memory (PR: 1.46; 95% CI: 1.16, 1.83) showed the strongest domain-specific associations. Educational level moderated this relationship, with higher education attenuating the association between cognitive impairment and gait speed.

CONCLUSION Global and domain-specific cognitive impairments, particularly in executive function and memory, were associated with slower gait speed. Education moderated this relationship, underscoring the role of cognitive and social factors in mobility outcomes among Brazilian older adults.