Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial
Snitz BE, O'Meara ES, Carlson MC, Arnold AM, Ives DG, Rapp SR, Saxton J, Lopez OL et al.. JAMA, 2009-12-01
Topic: Risk, prevention and care in population studies
Context The herbal product Ginkgo biloba is taken frequently with the intention of improving cognitive health in aging. However, evidence from adequately powered clinical trials is lacking regarding its effect on long-term cognitive functioning. Objective To determine whether G. biloba slows the rates of global or domain-specific cognitive decline in older adults. Design, setting, and participants The Ginkgo Evaluation of Memory (GEM) study, a randomized, double-blind, placebo-controlled clinical trial of 3069 community-dwelling participants aged 72 to 96 years, conducted in 6 academic medical centers in the United States between 2000 and 2008, with a median follow-up of 6.1 years. Intervention Twice-daily dose of 120-mg extract of G. biloba (n = 1545) or identical-appearing placebo (n = 1524). Main outcome measures Rates of change over time in the Modified Mini-Mental State Examination (3MSE), in the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-Cog), and in neuropsychological domains of memory, attention, visual-spatial construction, language, and executive functions, based on sums of z scores of individual tests. Results Annual rates of decline in z scores did not differ between G. biloba and placebo groups in any domains, including memory (0.043; 95% confidence interval [CI], 0.034-0.051 vs 0.041; 95% CI, 0.032-0.050), attention (0.043; 95% CI, 0.037-0.050 vs 0.048; 95% CI, 0.041-0.054), visuospatial abilities (0.107; 95% CI, 0.097-0.117 vs 0.118; 95% CI, 0.108-0.128), language (0.045; 95% CI, 0.037-0.054 vs 0.041; 95% CI, 0.033-0.048), and executive functions (0.092; 95% CI, 0.086-0.099 vs 0.089; 95% CI, 0.082-0.096). For the 3MSE and ADAS-Cog, rates of change varied by baseline cognitive status (mild cognitive impairment), but there were no differences in rates of change between treatment groups (for 3MSE, P = .71; for ADAS-Cog, P = .97). There was no significant effect modification of treatment on rate of decline by age, sex, race, education, APOE*E4 allele, or baseline mild cognitive impairment (P > .05). Conclusion Compared with placebo, the use of G. biloba, 120 mg twice daily, did not result in less cognitive decline in older adults with normal cognition or with mild cognitive impairment. Trial registration clinicaltrials.gov Identifier: NCT00010803.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Snitz, B. E., O'Meara, E. S., Carlson, M. C., Arnold, A. M., Ives, D. G., Rapp, SR., et al. (2009). Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial. JAMA. https://doi.org/10.1001/jama.2009.1913
Vancouver
Snitz BE, O'Meara ES, Carlson MC, Arnold AM, Ives DG, Rapp SR, et al. Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial. JAMA. 2009. doi:10.1001/jama.2009.1913. PMID: 20040554.
BibTeX
@article{snitz2009-20040554,
author = {Snitz, B. E. and O'Meara, E. S. and Carlson, M. C. and Arnold, A. M. and Ives, D. G. and Rapp, SR. and Saxton, J. and Lopez, O. L. and others},
title = {{Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial}},
journal = {JAMA},
year = {2009},
doi = {10.1001/jama.2009.1913},
pmid = {20040554},
url = {https://doi.org/10.1001/jama.2009.1913}
}
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Key findings
- Results Annual rates of decline in z scores did not differ between G. biloba and placebo groups in any domains, including memory (0.043; 95% confidence interval [CI], 0.034-0.051 vs 0.041; 95% CI, 0.032-0.050), attention (0.043; 95% CI, 0.037-0.050 vs 0.048; 95% CI, 0.041-0.054), visuospatial abilities (0.107; 95% CI, 0.097-0.117 vs 0.118; 95% CI, 0.108-0.128), language (0.045; 95% CI, 0.037-0.054 vs 0.041; 95% CI, 0.033-0.048), and executive functions (0.092; 95% CI, 0.086-0.099 vs 0.089; 95% CI, 0.082-0.096).
- There was no significant effect modification of treatment on rate of decline by age, sex, race, education, APOE*E4 allele, or baseline mild cognitive impairment (P > .05).
- Conclusion Compared with placebo, the use of G. biloba, 120 mg twice daily, did not result in less cognitive decline in older adults with normal cognition or with mild cognitive impairment.
Why it matters
In this large randomized trial of older adults, Ginkgo biloba did not slow cognitive decline in any measured domain compared with placebo. The results give no support for taking Ginkgo biloba to prevent or delay cognitive decline.
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Study details
- Participants1,545
- Evidence strengthHigh
How this study scored 79/100
Published in a top-tier journal, and it is a randomised controlled trial. Scored zero for effect reported because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 10 / 10 | Tier 1 — top-tier general journal (JAMA) |
| Journal's citation record | 4 / 4 | JAMA: journal h-index 1,011 (OpenAlex, 2026-10-29) |
| Study design | 11 / 12 | A randomised controlled trial (from PubMed type “Randomized Controlled Trial”) |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2009 — within 20 year(s) of the newest study here |
| Sample size | 3 / 4 | 1,545 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 2 / 2 | Randomised and blinded or placebo-controlled (as stated in the record) |
| Times cited | 6 / 7 | Cited 337 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 17.7 citations a year over 19 year(s) since 2009 |
| Impact for its field and year | 6 / 6 | Cited 63.6× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 11 other studies in this library |
| Still being cited | 2 / 4 | Cited 34 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Beth Ellen Snitz: h-index 57 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | University of Washington: institution h-index 3,540 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 6 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 20040554) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 79 / 100 | — |
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