Impact of Multivitamin‐Mineral and Cocoa Extract on Incidence of Mild Cognitive Impairment and Dementia: Results from the Cocoa Supplement and Multivitamin Outcomes Study for the Mind COSMOS‐Mind

Background COSMOS‐Mind, a large, randomized placebo‐controlled pragmatic trial in older adults, recently reported that daily supplementation with multivitamin‐mineral, but not cocoa extract, benefited global cognition. We assessed effects of these supplements on prespecified secondary outcomes of mild cognitive impairment (MCI) and all‐cause dementia (DM). We also assessed treatment‐related cognitive trajectories leading to conversion to MCI or dementia. Method COSMOS‐Mind (N = 2262) administered a telephone‐based cognitive battery at baseline and annually for 3 years. Proxies of participants meeting criteria for suspected cognitive impairment based on a cognitive screener (TICSm) were interviewed. An expert panel adjudicated cognitive status. Incidence rates of MCI, and separately DM, were compared among arms with proportional hazards regression. Changes in cognitive trajectories leading to MCI and DM were assessed with linear models. Result At baseline, adjudication for suspected cognitive impairment was triggered for 419 (20%) participants, yielding adjudications of 217 (10%) MCI and 4 (0.2%) DM cases. During follow‐up, triggers were less frequent in the MVM than placebo arms: hazard ratio = 0.73 (p = 0.04). Across 3 years, 110 incident MCI and 14 incident DM cases were adjudicated. Incidence rates of these outcomes did not vary by assignment to multivitamin‐mineral or cocoa extract (all p≥0.05), however statistical power was low. Incident MCI was associated with a marked decline in cognitive function from the previous year (p