Longitudinal association between brain volume change and gait speed in a general population

Objective: To determine the association between brain structural changes and gait speed in a four-year longitudinal prospective cohort study. Measurements: A total of 767 well-functioning community-dwelling participants, free of arthritis, silent infarct, stroke, dementia, head injury, and cancer, completed baseline brain magnetic resonance imaging scan and gait speed tests between 2011 and 2014, and follow-up tests between 2015 and 2017. The gait test consisted of measuring the elapsed time to walk four meters at usual speed. To estimate whether brain volume changes predict gait speed decline at follow-up, a generalized linear regression model was used after adjusting for potential confounding factors including gait speed at baseline. Results: Participants who experienced ≥0.05 m/s gait speed decline, previously defined as a clinically meaningful decline, were more likely to be women, less likely to be smokers, and had lower physical activity scores (p = 0.003, p = 0.025, and p = 0.006, respectively), as compared to those who did not experience the decline. Also, they demonstrated smaller volumes of hippocampus, total gray matter, parietal gray matter, temporal gray matter, and temporal white matter (p = 0.004, p = 0.042, p = 0.021, p = 0.001, and p = 0.004, respectively). Even after correcting the significance level due to multiple comparisons, overall gray matter and overall white matter volume changes during four-year follow-up period showed significant associations with gait speed at follow-up (p < 0.001 and p = 0.002). Regarding region-specific volumes, frontal white matter and parietal gray matter volume changes demonstrated significant associations with gait speed (p = 0.002, p = 0.004, respectively). Conclusion: In a four-year longitudinal study among 767 well-functioning community-dwelling healthy participants from a general population, we observed a significant association between brain volume changes and gait speed.