Ginkgo biloba for prevention of dementia: a randomized controlled trial
Steven T DeKosky, 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, Richard Nahin, Barbara Sorkin, Michelle C Carlson, Linda P Fried, Pat Crowley, Claudia Kawas, Paulo Chaves, Sevil Yasar, Patricia Smith, Joyce Chabot, John A Robbins, Katherine Gundling, Sharene Theroux, Linly Kwong, Lisa Pastore, Lewis Kuller, Roberta Moyer, Cheryl Albig, Gregory Burke, Steve Rapp, Dee Posey, Margie Lamb, Robert Hörr, Thorsten Schmeller, Joachim Herrmann, Richard A Kronmal, Annette L Fitzpatrick, Fumei Lin, Cam Solomon, Alice Arnold, Steven T DeKosky, Judith A Saxton, Oscar L Lopez, Diane G Ives, Leslie Dunn, Jeff D Williamson, Curt D Furberg, Nancy Woolard, Kathryn Bender, Susan Margitic, Russell P Tracy, Elaine Cornell, Carolyn Meltzer, Richard Grimm, Jonathan Berman, Hannah Bradford, Carlo Calabrese, Rick Chappell, Kathryn Connor, Gail Geller, Boris Iglewicz, Richard S Panush, Richard Shader, Steven T DeKosky, 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, Richard Nahin, Barbara Sorkin, Michelle C Carlson, Linda P Fried, Pat Crowley, Claudia Kawas, Paulo Chaves, Sevil Yasar, Patricia Smith, Joyce Chabot, John A Robbins, Katherine Gundling, Sharene Theroux, Linly Kwong, Lisa Pastore, Lewis Kuller, Roberta Moyer, Cheryl Albig, Gregory Burke, Steve Rapp, Dee Posey, Margie Lamb, Robert Hörr, Thorsten Schmeller, Joachim Herrmann, Richard A Kronmal, Annette L Fitzpatrick, Fumei Lin, Cam Solomon, Alice Arnold, Steven T DeKosky, Judith A Saxton, Oscar L Lopez, Diane G Ives, Leslie Dunn, Jeff D Williamson, Curt D Furberg, Nancy Woolard, Kathryn Bender, Susan Margitic, Russell P Tracy, Elaine Cornell, Carolyn Meltzer, Richard Grimm, Jonathan Berman, Hannah Bradford, Carlo Calabrese, Rick Chappell, Kathryn Connor, Gail Geller, Boris Iglewicz, Richard S Panush, Richard Shader
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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Source: PubMed