A clinical trial testing the effectiveness of long-term consumption of ginkgo biloba extract on appariation of risk reduction of Alzheimer’s disease in older people complaining about their memory.
A French randomized controlled trial of Vellas and colleagues published in the Lancet Neurology in 2012 evaluated for 5 years, the efficacy of the daily consumption of ginkgo biloba extract in people aged over 70 years old complaining of their memory. The results show that prolonged use of extract of ginkgo biloba does not reduce the risk of developing Alzheimer’s disease compared with placebo.
The Study Rationale
The number of affected persons with Alzheimer’s disease is expected to quadruple by 2050. memory impairment in the elderly are often associated with increased type of risk of dementia Alzheimer’s disease. People consulting a doctor for this type of disorder should be targeted for intervention for preventive.
Preventive intervention as the consumption of ginkgo biloba extract in older people with mnemonic difficulties could delay the onset of the disease a few years. A possible mechanism of action could be the powerful antioxidant effect of this natural extract. Studies have already demonstrated the safety of this extract in humans.
The objective of this study was to evaluate the efficacy of ginkgo biloba extract to reduce the risk of Alzheimer’s disease in people over 70 years old complaining of their memory.
Is ginkgo biloba extract an effective preventive strategy against Alzheimer’s disease?
The French controlled randomized trial of Vellas and colleagues evaluated the effectiveness of the daily intake of ginkgo biloba extract on the incidence of Alzheimer’s disease. Follow-up was 5 years. 25 French centers specializing in memory disorders participated in this study. They included 2820 people aged over 70 years whose mnemonic complaints were documented in a medial visit. People with major cognitive impairment, dementia, major depressive disorder or generalized anxiety disorder did not participate in the study. Participants were randomly assigned either to the group receiving ginkgo biloba extract or placebo group receiving a compressed appearance, odor and taste identical.
Cognitive, functional and depression were assessed each year. Safety is evaluated every three months by monitoring vital signs, performing physical and neurological examinations. Possible side effects have also been reported.
The Non-Pharmacological Intervention (NPI) assessed
The INM is to delay memory impairment in the elderly and prevent the onset of Alzheimer’s disease. Participants were asked to consume 120 mg of ginkgo biloba extract in tablet, 2 times a day for 5 years. The extract was purified and standardized to 24% ginkgo flavone glycosides and from 6% terpene lactones. The tablets were provided to patients during visits to the doctor every three months.
The study shows that after 5 years, 70 participants in the group in 1406 benefiting from the ginkgo biloba extract are diagnosed with Alzheimer’s disease in 1414 against 84 in the placebo group. But this difference is not statistically significant.
What it means for Patients
People over 70 years complain about their memory. This difficulty can sometimes announce future Alzheimer’s disease. Daily consumption of ginkgo biloba extract does not prove useful to protect this population from Alzheimer’s disease.
What it means for Healthcare Professionals
The daily consumption of 240 mg of ginkgo biloba extract did not reduce the incidence of dementia in 5 years in people over 70 years with complaints of memory.
What it means for Researchers
Randomized controlled trials of secondary prevention are rare. They require the inclusion of a large number of participants. This study is no exception to this principle. In fact, 4072 people participated in the initial phase of screening. Then, in 2854 people were followed for 5 years. We must congratulate this researchers and clinicians from 25 French centers that contributed to this study, the results make it possible to distinguish between a possible effect and a demonstrated effect between a hypothesis of efficiency and effectiveness. It allows clinicians to offer truly effective strategies and future research in the field of secondary prevention.
It should be noted that the incidence of Alzheimer’s disease in this study was lower than in the general population regardless of the group. This difference is explained by the authors in a higher socioeconomic level and better health of participants in the study compared to the general population. It is also possible to think that consultations every 3 months to a doctor, plus the repeated execution of medical examinations and neuropsychological testing has stimulated cognitively participants.
What it means for Policymakers
The daily consumption of 240 mg of ginkgo biloba extract for 5 years does not protect people over 70 years old complaining of their memory of Alzheimer’s disease. The study demonstrates the possibility of very rigorous secondary prevention studies that lead to real results useful to society as clinicians.
Vellas B, Coley N, Ousset PJ, Berrut G, Dartigues JF, Dubois B, Grandjean H, Pasquier F, Piette F, Robert P, Touchon J, Garnier P, Mathiex-Fortunet H, Andrieu S (2012). Long-term use of standardised ginkgo biloba extract for the prevention of Alzheimer’s disease (GuidAge): a randomised placebo-controlled trial. Lancet Neurology, 11, 851-859.
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Same non-pharmacological intervention
To reference this Blog en Sante © article.
Ninot G (2015). Ginkgo biloba does not protect against Alzheimer’s disease. Blog en Sante, A50.
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