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Randomized Controlled Trial
. 2008 Nov 19;300(19):2253-62.
doi: 10.1001/jama.2008.683.

Ginkgo biloba for prevention of dementia: a randomized controlled trial

Steven T DeKosky  1 , Jeff D Williamson, Annette L Fitzpatrick, Richard A Kronmal, Diane G Ives, Judith A Saxton, Oscar L Lopez, Gregory Burke, Michelle C Carlson, Linda P Fried, Lewis H Kuller, John A Robbins, Russell P Tracy, Nancy F Woolard, Leslie Dunn, Beth E Snitz, Richard L Nahin, Curt D Furberg; Ginkgo Evaluation of Memory (GEM) Study Investigators
Collaborators, Affiliations
Randomized Controlled Trial

Ginkgo biloba for prevention of dementia: a randomized controlled trial

Steven T DeKosky et al. JAMA. .

Erratum in

  • JAMA. 2008 Dec 17;300(23):2730

Abstract

Context: Ginkgo biloba is widely used for its potential effects on memory and cognition. To date, adequately powered clinical trials testing the effect of G. biloba on dementia incidence are lacking.

Objective: To determine effectiveness of G. biloba vs placebo in reducing the incidence of all-cause dementia and Alzheimer disease (AD) in elderly individuals with normal cognition and those with mild cognitive impairment (MCI).

Design, setting, and participants: Randomized, double-blind, placebo-controlled clinical trial conducted in 5 academic medical centers in the United States between 2000 and 2008 with a median follow-up of 6.1 years. Three thousand sixty-nine community volunteers aged 75 years or older with normal cognition (n = 2587) or MCI (n = 482) at study entry were assessed every 6 months for incident dementia.

Intervention: Twice-daily dose of 120-mg extract of G. biloba (n = 1545) or placebo (n = 1524).

Main outcome measures: Incident dementia and AD determined by expert panel consensus.

Results: Five hundred twenty-three individuals developed dementia (246 receiving placebo and 277 receiving G. biloba) with 92% of the dementia cases classified as possible or probable AD, or AD with evidence of vascular disease of the brain. Rates of dropout and loss to follow-up were low (6.3%), and the adverse effect profiles were similar for both groups. The overall dementia rate was 3.3 per 100 person-years in participants assigned to G. biloba and 2.9 per 100 person-years in the placebo group. The hazard ratio (HR) for G. biloba compared with placebo for all-cause dementia was 1.12 (95% confidence interval [CI], 0.94-1.33; P = .21) and for AD, 1.16 (95% CI, 0.97-1.39; P = .11). G. biloba also had no effect on the rate of progression to dementia in participants with MCI (HR, 1.13; 95% CI, 0.85-1.50; P = .39).

Conclusions: In this study, G. biloba at 120 mg twice a day was not effective in reducing either the overall incidence rate of dementia or AD incidence in elderly individuals with normal cognition or those with MCI. Trial Registration clinicaltrials.gov Identifier: NCT00010803.

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Figures

Figure 1
Figure 1
Flow of Participants Through the Ginkgo Evaluation of Memory (GEM) Study PD indicates Parkinson disease.
Figure 2
Figure 2
Cumulative Adherence to Assigned Study Tablets by Scheduled 6-Month Follow-up Visit (Excluding Death and Incident Dementia) Study visit No. 3 was the first 6-month follow-up visit after randomization.
Figure 3
Figure 3
Cumulative Dementia Rates by Treatment CI indicates confidence interval; HR, hazard ratio.
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