Lower cerebral vasoreactivity as a predictor of gait speed decline in type 2 diabetes mellitus

Gait speed is an indicator of overall functional health and is correlated with survival in older adults. We prospectively evaluated the long-term association between cerebral vasoreactivity and gait speed during normal walking (NW) and dual-task walking (DTW) in older adults with and without type 2 diabetes mellitus (T2DM). 40 participants (aged 67.3 ± 8.8 years, 20 with T2DM) completed a 2-year prospective study consisting of MRI, blood sampling, and gait assessments. The whole brain vasoreactivity was quantified using continuous arterial spin labeling MRI. Gait speed during DTW was assessed by subtracting serial sevens. Dual-task cost was calculated as the percent change in gait speed from NW to DTW. In the entire cohort, higher glycemic profiles were associated with a slower gait speed. In the diabetic group, lower vasoreactivity was associated with a slower gait speed during NW (radj2 = 0.30, p = 0.019) and DTW (radj2 = 0.35, p = 0.01) and a higher dual-task cost (radj2 = 0.69, p = 0.009) at 2-year follow-up. The participants with T2DM and lower cerebral vasoreactivity had a greater decrease in gait speed during NW and DTW after the 2-year follow-up (radj2 = 0.17, p = 0.04 and radj2 = 0.28, p = 0.03, respectively). Longer diabetes duration was associated with a higher dual-task cost (radj2 = 0.19, p = 0.04) and a greater decrease in gait speed during NW (radj2 = 0.17, p = 0.02). These findings indicate that in older adults with type 2 diabetes, gait performance is highly dependent on the integrity of cerebrovascular regulation.