Background: Dementia is a major cause of disability in aging. However, there are few clinical trials testing interventions targeting primary prevention of dementia in the elderly. Ginkgo biloba (EGb761) is a plant extract with powerful antioxidant activity and possible anti-amyloid activity. We report results of the Ginkgo Evaluation of Memory Study (GEMS), a trial of the effectiveness of Ginkgo biloba in delaying the incidence of AD/all cause dementia. We wished test the effectiveness of 120 mg BID of Ginkgo biloba vs. placebo in lowering the incidence of AD/dementia in normal elderly or those with mild cognitive impairment (MCI). Secondary outcomes included effects of Ginkgo on cognitive change over time, vascular disease, functional decline, adverse events, and mortality. Methods: A randomized, double-blind, placebo-controlled clinical trial conducted at 4 academic sites in the US. A total of 3,071 subjects age 75+ with normal cognition or MCI were randomized to either Ginkgo or placebo after extensive medical and neuropsychological screening, including the Clinical Dementia Rating (CDR) performed with each participant's proxy. Assessments were performed every 6 months; pre-defined change in cognitive scores/CDR led to more extensive testing and evaluation for dementia, including neuroimaging. Dementia outcome and specific dementia diagnosis were determined by consensus of an expert panel. Results: A total of 440+ persons developed dementia over the course of the study, extending 8 years from initial recruiting to date of last person/last visit. Mortality and subjects lost to follow-up were well below expected rates and Ginkgo was well tolerated. Conclusions: Statistical analysis of the trial results will be presented at the meeting. Dementia incidence is an assessable outcome in primary prevention trials. Substantial information from GEMS will be of benefit to designing future prevention trials assessing medication effectiveness.
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