Ginkgo biloba for prevention of dementia: a randomized controlled trial.
BACKGROUND
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).


METHODS
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.


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


METHODS
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.
DeKosky
Steven T
ST
University of Pittsburgh, Pittsburgh, Pennsylvania, USA. dekosky@virginia.edu
Williamson
Jeff D
JD
Fitzpatrick
Annette L
AL
Kronmal
Richard A
RA
Ives
Diane G
DG
Saxton
Judith A
JA
Lopez
Oscar L
OL
Burke
Gregory
G
Carlson
Michelle C
MC
Fried
Linda P
LP
Kuller
Lewis H
LH
Robbins
John A
JA
Tracy
Russell P
RP
Woolard
Nancy F
NF
Dunn
Leslie
L
Snitz
Beth E
BE
Nahin
Richard L
RL
Furberg
Curt D
CD
D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology / Q000517:prevention & control; D003071:Cognition; D003704:Dementia / Q000453:epidemiology / Q000517:prevention & control*; D004311:Double-Blind Method; D020441:Ginkgo biloba; D006801:Humans; D015994:Incidence; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D000096983:Ginkgo Extract
D010936:Plant Extracts; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract