Alzheimer’s Foundation of America Comment on State-of-the-Science Panel Statement on Preventing Alzheimer’s Disease and Cognitive Decline
The Alzheimer’s Foundation of America (AFA) issued this comment on the National Institutes of Health state-of-the-science panel statement “Preventing Alzheimer’s Disease and Cognitive Decline” released on April 28, 2010. The independent panel drafted its statement based on a review of scientific literature and presentations at a day-two open forum. The statement is available at http://consensus.nih.gov/2010/alzstatement.htm.
The conclusions drawn by the panel of experts are both good news and bad news for the dementia care community that AFA serves. The good news is that the concept of dementia promoted by AFA conforms with the best available scientific data; however, the bad news is that inadequate data is available to absolutely define the impact of successful aging strategies.
The process was thoughtful, balanced and inclusive, and the panel’s determination illustrates the complexity and uncertainty surrounding this issue. It is critical to note that the absence of confirmatory data does not imply evidence that an intervention is a failure. The nation’s limited investment in dementia research has contributed to inadequate quantities of research to confirm these complex issues. AFA’s successful aging message remains unchanged and is consistent with the best available data provided by the panel of experts.
While the panel found that there currently is no evidence of “even moderate scientific quality” supporting any modifiable factors such as supplement intake, use of prescription or non-prescription drugs, diet, exercise or social engagement as a way to reduce an individual’s risk for Alzheimer's disease, and “low-grade” evidence showing weak associations between many lifestyle choices and reduced risk, it said that some of these interventions may confer other benefits. Little evidence presented suggests that interventions designed to improve cognitive function either worsen it or produce unwanted side effects.
The panel was careful to avoid any message that suggested individuals should abandon good health habits, such as exercise, weight control or management of hypertension, despite the fact that the published data is not adequate to tell Americans that engaging in these activities will prevent or reduce the risk for dementia.
It is clear, as everyone on the panel concurred, that the nation’s level of scientific investment in Alzheimer’s disease is massively underfunded in comparison to the scope of the looming public health problem for this disorder. The discussion highlighted the many unanswered questions related to the pathology and treatment of dementia. The presenters strongly suggested that these brain disorders are highly complex with multiple pathologies. None of the panelists suggested that breakthrough treatments or a cure for dementia are imminent. In addition, no scientist suggested that a specific molecule, such as amyloid or tau, holds the key to dementia and that manipulation of that molecule will cure or reverse these brain changes. The panel did not conclude that available treatments were futile, but rather that they would not prevent or stop brain damage produced by these diseases. These scientific observations related to pathology and treatment are consistent with AFA’s position and have been the basis of our long-standing message that America must prepare for a decade of care in order to support individuals living with dementia and manage expenses associated with long-term care.
There was a general sense that vascular pathology played a major role in dementia for older individuals. Likewise, there was relatively good support for the concept that hypertension may be a risk factor for the development of dementia; however, the preventive impact of treating hypertension remains unclear. The panel supported long-term compliance for hypertension as a treatment strategy that provides multiple health benefits, but said there is inadequate data to show that treatment of hypertension will prevent intellectual decline or dementia. However, it found no evidence to disprove the concept that aggressive treatment of hypertension during midlife will slow or prevent the loss of intellectual function in later life.
The panel discussed genetic testing and other predictive testing for dementia as well as biomarkers such as PET scans and spinal fluid levels of amyloid and tau. The panel did not conclude that any specific genetic test, such as APOE genotype, had adequate data to support the ability to predict dementia. The discussion did not suggest that a single scan or spinal fluid level would be developed to predict the likelihood of developing dementia in later life. Moreover, there was little discussion about the financial feasibility of performing PET scans or spinal taps on larger numbers of middle-age individuals.
There are several important conclusions from this panel. First, dementia is often, if not usually caused by a complex mixture of age or disease related pathologies. This complexity may produce the lack of efficacy data on treatment and prevention. Second, given indications that interventions to improve cognitive function are not harmful, AFA will continue to encourage health behaviors, such as exercise or control of hypertension, that have multiple other proven health benefits, and spotlight the available, credible scientific data that suggests brain benefits. Finally, the preventions and possible cures for dementia are unlikely to occur in the near future. The nation must prepare for a decade of care and expand the focus on caregiver issues while it increases the investment in dementia research.
From Richard E. Powers, M.D., chairman, AFA Medical Advisory Board:
To understand the conclusions of the panel, the public must understand the process it used to develop these recommendations. It included: 1.) a systematic review of all published literature 2.) oral presentations by 21 nationally-recognized experts in critical areas of research 3.) questions and statements from conference attendees, and 4.) review by impartial experts with expertise in critical public health issues other than dementia. This process assures that an impartial, thoughtful recommendation occurs.
As a member of the audience during the open forum, I concluded that the presentations were thoughtful, balanced and complete. The panel gave the audience ample opportunity to discuss the issues and raise concerns. Candid and sometimes confrontational exchanges occurred that pointed to genuine differences of opinions.
The panel was sensitive to possible adverse impacts of their conclusion that inadequate data exists, and the chairwoman was clear that the absence of confirmatory data does not suggest that a particular intervention is proven to be non-effective. The final conclusion focused on several interventions, such as exercise, intellectual stimulation and good basic medical care, that the panel suspected may hold great promise in the future with additional research. The panel is duty-bound to only recommend those interventions supported by clear, unequivocal, confirmatory evidence of effectiveness.