Synergistic effects of exercise, cognitive training and vitamin D on gait performance and falls in mild cognitive impairment-secondary outcomes from the SYNERGIC trial.

Background: Older adults with mild cognitive impairment (MCI) have a higher risk of gait impairments and falls; yet, the effects of multimodal interventions, including combinations of exercises with cognitive training, on improving their mobility remain unclear.

Objectives: To investigate the synergistic effects of aerobic-resistance exercise combined with cognitive training, with or without vitamin D supplementation, on gait performance and falls risk in older adults with MCI.

Methods: The effect of 20 weeks of aerobic-resistance exercise, cognitive training, and Vitamin D supplementation (10 000 IU 3×/week) on gait and falls in older adults with MCI was evaluated in the SYNERGIC trial, using a fractional factorial design. Assessments were conducted at baseline, 6-month endpoint (after intervention) and 12-month endpoint (follow-up). Eligible participants were between the ages of 65 and 84 years with MCI enrolled from 19 September 2016 to 7 April 2020. Main outcomes of interest for gait performance were gait speed and gait variability changes, whilst for falls were incidental falls and incidental injurious falls.

Results: Amongst 161 participants, the four exercise-based arms improved gait speed (+7.5 cm/s, P < .001) and reduced falls (incidence rate ratios (IRR) = 0.65, 95% confidence interval (CI): 0.32-1.42, P = .25) and injurious falls (IRR = 0.38, 95% CI: 0.15-1.05, P = .05) at 6-month endpoint. Falls reduction reached statistical significance (IRR = 0.28, 95% CI: 0.13-0.64, P = .002) at 12-month endpoint. Exercises combined with cognitive training showed the greatest gains in gait speed at 6-month endpoint (P < .001) and in reducing falls at 12-month endpoint (IRR = 0.24, 95% CI: 0.05-0.77, P = .02) compared to the control. Vitamin D did not enhance outcomes and increased gait variability, a marker of instability.

Conclusion: Aerobic-resistance exercise combined with sequential computerised cognitive training improved gait performance at 6 months and decreased the risk of falls and injuries at 12 months in older adults with MCI. The addition of vitamin D did not produce benefits.