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: Randomised 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 programme (WP, n = 77) or a low-intensity placebo activity programme (n = 75) for one year; and ( 2) daily vitamin pill containing 5 mg folic acid, 0.4 mg vitamin B-12, 50 mg vitamin B-6 (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 at the exercise programmes (25th-75th percentile) was 63% (2%-81%) and median compliance with taking pills (25th-75th percentile) was 100% (99%-100%). 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 percentage increase in session attendance. In men attending at least 75% of the sessions, the WP improved memory (beta 1.5 (95% CI: 0.1 to 3.0) words). Conclusion: The walking programme and/or FA/B12/B6 supplementation were not effective in improving cognition within one year. The walking programme, however, was efficacious in improving memory in men and memory and attention in women with better adherence. Trial registration: International Standard Randomised Controlled Trial Number Register, 19227688, http://www.controlled-trials.com/isrctn/.