An independent panel of experts meeting in the US concluded there is no evidence that you can prevent or slow down Alzheimer’s, a progressive and fatal brain disease, even if you keep yourself active with exercise, social interaction, brain puzzles, or take fish oil, other supplements, or medication.
The panel of 15 disease experts, who may not be federal government employees or have financial interests in the treatments considered, met on Wednesday just outside Washington as part of the National Institutes of Health’s (NIH’s) Office of Medical Applications of Research (OMAR) state-of-the-science conference program.
A report of their study, the purpose of which was to assess whether the evidence so far on Alzheimer’s disease and cognitive decline risk factors and prevention was strong enough to warrant specific treatment recommendations and guidelines, is available online through the Agency for Healthcare Research and Quality.
The panel, which included experts in geriatrics, long-term care, nursing and psychiatry, examined dozens of studies that have proposed ways to prevent Alzheimer’s disease, but found none was sufficiently robust to constitute proof.
Dr Martha Daviglus of Northwestern University in Chicago, who chaired the panel, told the press that most of the studies only show links, they don’t prove cause and effect between a factor and disease prevention.
She said it was like the chicken and egg, which came first: do people stay mentally sharp because they stay active and socially engaged, or do they stay socially engaged and active because they are mentally sharp?
“We wish we could tell people that taking a pill or doing a puzzle every day would prevent this terrible disease, but current evidence doesn’t support this,” said Daviglus, according to a Reuters news agency report.
Daviglus and colleagues evaluated the literature against a group of factors that took into account: “nutrition, medical conditions, prescription and non-prescription medications, social/economic/behavioral factors, toxic environmental factors, and genetics”.
They only included studies where outcomes included a diagnosis of Alzheimer’s disease (AD) or cognitive decline, and they evaluated both intervention (eg randomized controlled trials) and observational studies.
25 systematic reviews and 250 primary research studies met their inclusion criteria. On further analysis they found that:
- Only a few factors showed a consistent link with AD or cognitive decline across a number of observational and randomized controlled trials.
- Factors linked to increased risk of AD and cognitive decline were: diabetes, genetic (presence of APOE e4 gene), smoking, and depression.
- Factors showing a “fairly consistent association” with decreased risk of AD and cognitive decline were: cognitive engagement and physical activities.
- The modification to risk was typically small to moderate for AD and small for cognitive decline.
However, the panel stressed that:
“A consistent association does not imply that findings were robust, as the data were often limited, and the quality of evidence was typically low.”
And they noted that:
“Many of the factors evaluated are not amenable to randomization, so rigorous observational studies are required to assess their effect on AD and cognitive decline.”
In their conclusions they noted that the current evidence is not enough to enable a confident assessment of links with AD or cognitive decline.
“Further research that addresses the limitations of existing studies is needed prior to be able to make recommendations on interventions,” they wrote.
According to the latest report from the Alzheimer’s Association, Alzheimer’s Facts and Figures, 2010, there are over 5 million Americans living with the disease today.
The report also reveals that African-Americans and Hispanics are at higher risk for developing Alzheimer’s, with African- Americans are about twice as likely, and Hispanics are about 1.5 times more likely than whites to develop the disease.
However, although African-Americans and Hispanics have a higher rate of Alzheimer’s and dementia, they are less likely than whites to have a diagnosis.