Intervention Review

Ginkgo biloba for cognitive impairment and dementia

  1. Jacqueline Birks1,*,
  2. John Grimley Evans2

Editorial Group: Cochrane Dementia and Cognitive Improvement Group

Published Online: 21 JAN 2009

Assessed as up-to-date: 25 MAR 2008

DOI: 10.1002/14651858.CD003120.pub3

How to Cite

Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD003120. DOI: 10.1002/14651858.CD003120.pub3.

Author Information

  1. 1

    University of Oxford, Centre for Statistics in Medicine, Oxford, UK

  2. 2

    University of Oxford, Division of Clinical Geratology, Nuffield Department of Clinical Medicine, Oxford, UK

*Jacqueline Birks, Centre for Statistics in Medicine, University of Oxford, Wolfson College, Linton Road, Oxford, OX2 6UD, UK. jacqueline.birks@csm.ox.ac.uk.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 21 JAN 2009

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

Products of the maidenhair tree, Ginkgo biloba, have long been used in China as a traditional medicine for various disorders of health. A standardized extract is widely used in the West for the treatment of a range of conditions including memory and concentration problems, confusion, depression, anxiety, dizziness, tinnitus and headache. The mechanisms of action are thought to reflect the action of several components of the extract and include increasing blood supply by dilating blood vessels, reducing blood viscosity, modification of neurotransmitter systems, and reducing the density of oxygen free radicals.

Objectives

To assess the efficacy and safety of Ginkgo biloba for dementia or cognitive decline.

Search methods

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 20 September 2007 using the terms: ginkgo*, tanakan, EGB-761, EGB761, "EGB 761" and gingko*. The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trials databases and grey literature sources.

Selection criteria

Randomized, double-blind studies, in which extracts of Ginkgo biloba at any strength and over any period were compared with placebo for their effects on people with acquired cognitive impairment, including dementia, of any degree of severity.

Data collection and analysis

Data were extracted from the published reports of the included studies, pooled where appropriate and the treatment effects or the risks and benefits estimated.

Main results

36 trials were included but most were small and of duration less than three months. Nine trials were of six months duration (2016 patients). These longer trials were the more recent trials and generally were of adequate size, and conducted to a reasonable standard. Most trials tested the same standardised preparation of Ginkgo biloba, EGb 761, at different doses, which are classified as high or low. The results from the more recent trials showed inconsistent results for cognition, activities of daily living, mood, depression and carer burden. Of the four most recent trials to report results three found no difference between Ginkgo biloba and placebo, and one reported very large treatment effects in favour of Ginkgo biloba.

There are no significant differences between Ginkgo biloba and placebo in the proportion of participants experiencing adverse events.

A subgroup analysis including only patients diagnosed with Alzhiemer's disease (925 patients from nine trials) also showed no consistent pattern of any benefit associated with Ginkgo biloba.

Authors' conclusions

Ginkgo biloba appears to be safe in use with no excess side effects compared with placebo. Many of the early trials used unsatisfactory methods, were small, and publication bias cannot be excluded. The evidence that Ginkgo biloba has predictable and clinically significant benefit for people with dementia or cognitive impairment is inconsistent and unreliable.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

There is no convincing evidence that Ginkgo biloba is efficacious for dementia and cognitive impairment

Ginkgo biloba appears to be safe in use with no excess adverse effects compared with placebo. Many of the early trials used unsatisfactory methods, were small, and publication bias cannot be excluded. Overall, evidence that Ginkgo has predictable and clinically significant benefit for people with dementia or cognitive impairment is inconsistent and unreliable. Of the four most recent trials to report results, three found no difference between Ginkgo biloba and placebo, and one reported very large treatment effects in favour of Ginkgo biloba.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

使用銀杏治療認知功能障礙跟失智症

銀杏樹上的果實,銀杏,長期在中國都被當作各種病痛的傳統療法。在西方,標準化的銀杏萃取物則被用來治療各種不同的疾病,包含記憶力跟集中力問題,混亂,憂鬱,焦慮,頭暈,耳嗚跟頭痛。銀杏的作用機轉被認為可能與萃取液的數種成分有關並且可以藉由擴張血管以增加血流供給,降低血液黏稠度,修正神經傳遞物質系統和減少氧化自由基。

目標

本研究的主要目的在於評估使用銀杏對於失智症和認知功能衰退的療效和安全性。

搜尋策略

在2007年9月20日使用The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG)、Cochrane Library、MEDLINE、EMBASE、PsycINFO、CINAHL和 LILACS資料庫針對「ginkgo*, tanakan, EGB761, EGB761, "EGB 761" 和 gingko*」進行檢索, CDCIG資料庫包含所有主要健康照顧資料庫(The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS)、很多試驗資料庫和很多灰色文獻來源。

選擇標準

比較使用任何強度或是任何時期萃取的銀杏和安慰劑在所有嚴重程度的後天認知功能障礙病患包括失智症相關的隨機、雙盲試驗都納入本研究中。

資料收集與分析

從納入本研究的報告中擷取資料進行適度彙整,並評估治療效果、風險和效益。

主要結論

有36個試驗被納入,但大多是小型的和治療時間少於三個月。有9個持續了6個月的試驗 (2016位病患),這些較長期的試驗大部份都是最近的試驗且納錄足夠的病患以及執行合理化的標準。這些試驗都是使用相同標準化製備的銀杏萃取物(EGb 761),但依劑量不同可分成高與低劑量。最近試驗結果顯示在認知功能,日常生活活動性,情緒,憂鬱和照顧者負擔上的結果是不一致的。最近4個試驗中,有3個試驗認為銀杏和安慰劑無明顯差異,有1個試驗指出銀杏具有很好的治療效果。銀杏和安慰劑對受試者所引發的不良事件並沒有差異。有一個次分組試驗只收錄被診斷患有阿茲海默症患者(由個試驗納入的925名患者),其結果也顯示銀杏並無確切的療效。

作者結論

銀杏與安慰劑比較顯示,在使用上是安全的沒有副作用。很多早期試驗的方法都不夠嚴謹,包括試驗規模太小和不能排除出版偏差。關於過去認為銀杏對於失智症或認知功能障礙病患具有療效的證據是不一致的且不可靠的。

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

銀杏與安慰劑比較顯示,在使用上是安全的沒有副作用。很多早期試驗的方法都不夠嚴謹,包括試驗規模太小和不能排除出版偏差。綜合來說,關於過去認為銀杏對於失智症或認知功能障礙病患具有療效的證據是不一致的且不可靠的。最近4個試驗中,有3個試驗認為銀杏和安慰劑無明顯差異,有1個試驗指出銀杏具有很好的療效。