Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS.
Level 1 - systematic review of randomized trials
Meta-analysis of three randomized controlled trial cognitive substudies within the COSMOS parent trial
PubMed 38244989 · doi:10.1016/j.ajcnut.2023.12.011
What was done
Within the 2 × 2 factorial COcoa Supplement and Multivitamin Outcomes Study (COSMOS) in US adults aged ≥60 years, 573 participants in the COSMOS-Clinic subcohort completed in-person neuropsychological assessments at baseline and over 2 years to test the effect of daily multivitamin-mineral (MVM) supplementation versus placebo. Authors also conducted a meta-analysis pooling non-overlapping participants across three COSMOS cognitive substudies: COSMOS-Clinic (n = 573), COSMOS-Mind (n = 2,158), and COSMOS-Web (n = 2,472).
What was found
In the COSMOS-Clinic subcohort over 2 years, MVM compared to placebo produced a non-statistically significant improvement in global cognition (mean difference [MD] = 0.06 standard deviation units [SU], 95% CI: -0.003 to 0.13), a significant improvement in episodic memory (MD = 0.12 SU, 95% CI: 0.002 to 0.23), and no effect on executive function/attention (MD = 0.04 SU, 95% CI: -0.04 to 0.11). The pooled meta-analysis showed significant improvements in both global cognition (MD = 0.07 SU, 95% CI: 0.03 to 0.11; P = 0.0009) and episodic memory (MD = 0.06 SU, 95% CI: 0.03 to 0.10; P = 0.0007), equivalent to slowing cognitive aging by 2 years.
Why it matters
This study provides replicated randomized trial evidence that a daily multivitamin-mineral supplement yields modest benefits for memory and overall cognitive function in older adults across varying assessment modes.
Limits
Effect sizes were small (0.06 to 0.07 standard deviation units). The in-person clinic subcohort was modestly sized and lacked statistical power to confirm global cognitive benefits independently. The abstract does not evaluate baseline dietary/nutritional adequacy, adverse events, or progression to clinical dementia.