Abstract

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 twice-weekly, 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 at 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. Trial Registration: International Standard Randomized Controlled Trial Number Register, 19227688, http://www.controlled-trials.com/isrctn/.