Introduction:
The article ‘Ginkgo cannot prevent Alzheimer’s’ was taken from the ‘Mind your body’ section of
The Straits Times, published on September 13, 2012. The article presents us with a study
which was conducted across a span of 5 years on 2,854 elderly, aged 70 years or above, in
France who had approached doctors and expressed concerns about their memory. 1,406
patients were administered with Ginkgo biloba extract while the remaining 1,414 patients were
prescribed dummy pill or placebo. Both groups were required to consume 2 doses daily. The
article claims that Ginkgo biloba extract which can be easily acquired over the counter, is not
effective in preventing the onset of Alzheimer’s disease.
Review:
Component 1: The source of the research and of the funding
The trial was conducted by researchers and led by Dr. Bruno Vellas of the Hospital Casselardit
in Toulouse, France. The source of funding was unstated in the newspaper article. There may
be propaganda underlying the research. Two hypothetical situations could lead us to different
conclusions about the applicability of the results of the study. First of all, the government may
have funded this research for the benefit of its people. This is especially so for countries with
ageing population as age-related diseases like Alzheimer’s disease are more prevalent. Thus,
they may have funded this research in hopes of finding drugs that can boost mental dexterity.
As governments usually have no benefit from either side of the research results, it is unlikely
that the source of funding will influence how the study was conducted and reported. Secondly,
this may be an attempt by a private pharmaceutical company to undermine its rival company’s
product These rival companies are money driven, profiteering and want to get the lion’s share of
the market.
Component 2: The researchers who had contacts with the participants
It is not known if the study conducted was doubled-blinded. If the researchers knew which is the
placebo group, they may disclose subtle hints which may lead to inconclusive results when
picked up by the patients. The researchers may also be dispatched from a private
pharmaceutical company and are consequently biased to a particular outcome. Hence, they
may behave in a way, albeit subconsciously, that causes the patient to feel obliged to comply
with the desires of the researchers.
Component 3: The individuals or objects studied and how they were selected
The study involved a total of 2,854 people living in France, who were more than 70 years of age
and had already visited their doctors with concerns about their memory. Firstly, the people
involved in this study were chosen for convenience purposes as the study was conducted in
France and hence, only people living in that country were chosen. This means that the sample
size is not a good representative of the true population which is the world population. Therefore,
the results of this study may not be applicable to people of another demographic background.
Also, the individuals were chosen as they had issues regarding their memory functions.
However, there is no mention of what kind of baseline the researchers had set to classify the
extent of memory loss the person is experiencing. Also, it is hard to determine the symptoms
associated with memory loss. It could just be the individuals had been lacking sleep or been
surrounded by distractions that prevent them from recalling past memories. Moreover, the
patients recruited in the study may be selected from public hospitals which may be preferred
over private hospitals due to more accessible information. As people consulting public hospitals
tend to be from lower income families, they may have allowed their conditions to worsen
considerably before finally consulting their physicians, unlike affluent people who generally
consult doctors the moment they feel that there is anything wrong with their memory. As a
result, the results may be affected.
Component 4: The exact nature of the measurements made or questions asked
1,406 patients were given the Ginkgo biloba extract while 1,414 patients were given placebo
and the study was conducted over five years. The researchers then used standard tests to
assess the patients’ memory, cognitive function and dementia status. It is not stated what kind
of standard tests were used. Although it is good that the tests used are standardised for all
individuals, which means that the variation of results due to measurement methods will be
eliminated, however there is no mention of whether the tests are used repeatedly over the five
years or whether different tests are used each year. This can be a decisive factor because if the
individuals are subjected to the same tests each year, they can possibly memorise the answers
and thus affecting the results of this study. Also, there is a plethora of dialects in France based
on the different regions. The researchers in the context may not be proficient in the different
varieties of French language and thus may change the way the participants perceive the
questions, giving rise to erroneous results.
Component 5: The setting in which the measurements were taken
It is not mentioned in the report whether the settings in which measurements were taken were
kept consistent for both groups and during the span of 5 years. Patients may also do better in
cognitive and memory tests when in familiar and comfortable surroundings as compared to a
research lab. The timing of the tests can also lead to differences in results as if tests are taken
after meal times, the well-fed state of the participants may also hinder their memory and
cognitive abilities.
Component 6: Differences in the groups being compared, in addition to the factor of
interest
It was not mentioned in the article how the sample population was divided into the 2 groups for
the study. If the groups are not divided randomly, it may bring inaccuracies to the overall results
as there are other factors that can influence the onset of Alzheimer’s disease. For example, as
they are all elderly, it is likely that they have other ailments and may be consuming other drugs
or herbs as well. The other medicines consumed may interact with the ginkgo extract or have
effects on memory and cognitive function on its own. The study selected patients who seeked
medical help due to memory problems and areas with accessible medical facilities are likely to
be in the more developed regions of France. The elderly in such areas may be subjected to
greater stress as compared to their counterparts residing in rural areas who lead sedentary
lifestyles. Their more stressful lifestyle may exacerbate memory loss.
Component 7: The extent or size of any claimed effects or differences
The article noted that 61 out of 1406 participants in ginkgo group and 73 patients out of 1414
participants in placebo group was diagnosed with probable Alzheimer’s disease. This translates
to 4 percent of gingko group and 5 percent of participants in placebo group who contracted
Alzheimer’s disease.
Conclusion
The newspaper article appears to be quite concise and complete but upon further
statistical analysis, we realised that by leaving out several components, it might lead to
erroneous results and thus distorting the conclusion. Hence, this shows the importance
to state all the components when summarising and analysing statistical studies.