Walking or vitamin B for cognition in older adults with mild cognitive impairment? A randomised controlled trial

Objective: To examine the effects of aerobic exercise or vitamin B supplementation on cognitive function in older adults with mild cognitive impairment (MCI).Design: Randomized placebo-controlled trial.Setting: General community.Participants: community-dwelling adults aged 70-80 with MCI.Interventions: The 152 participants were randomly assigned to two interventions: 1) a twiceweekly, group-based, moderate-intensity walking program (WP, n=77) or a low-intensity placebo activity program (n=75) for one year; and 2) daily vitamin pill containing 5 mg folic acid, 0.4 mg vitamin B12, 50 mg vitamin B6 (FA/B12/B6, n=78) or placebo-pill (n=74) for one year.Outcome measures: Cognitive function, measured with neuropsychological tests at baseline and after six and 12 months.Results: Median session attendance to the exercise programs (25th-75th percentile) was 63 (2-81) percent and median compliance with taking pills (25th-75th percentile) was 100 (99-100) percent.Gender was an effect-modifier.Intention-to-treat analysis revealed no main intervention effect for either intervention.In women in the WP, attention (Stroop combination task) improved by 0.3 seconds (p=0.04) and memory (auditory verbal learning test) by 0.04 words (p=0.06) with each percent increase in session attendance.In men attending at least 75 percent of the sessions, the WP improved memory (beta [95%CI]= 1.5 [0.1; 3.0] words). Conclusion:The walking program and/or FA/B12/B6 supplementation were not effective in improving cognition within one year.The walking program, however, was efficacious in improving memory in men and memory and attention in women with better adherence.