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The Unfortunate NIH Report on Alzheimer's Disease

Posted: 05/18/10 10:00 AM ET

The National Institute of Health arranged for a panel to determine whether or not there is anything a person can do to reduce their risk of developing Alzheimer's Dementia. This study was recently published with the title: "Preventing Alzheimer's Disease and Cognitive Decline." The conclusion of the this large, 727 page report was, "The current research on the list of putative risk or protective factors is largely inadequate to confidently assess their association 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."

If this is taken to mean that we need to learn more about Alzheimer's Disease, then I completely agree. However, if this is taken to mean that we have no idea what causes Alzheimer's Disease and absolutely no idea what to do to reduce the risk of developing the illness, I must vehemently disagree.

Dr. Martha Daviglus of Northwestern University in Chicago, the physician who chaired the panel, went on to tell the media, "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." In reply to Dr. Daviglus, I must state that neither I nor any other competent author on the subject believes that simply taking a pill or doing a puzzle every day will significantly reduce the risk of developing Alzheimer's Disease. As I think Dr. Daviglus would agree, the story is more complicated than that.

It is important to state that we know a lot about the risk factors for Alzheimer's Disease. Some forms of Alzheimer's Disease are very strongly related to genetics, appear early in life, and may not be avoidable. On the other hand, we know that choices we make in life influence the risk of developing the most common forms of Alzheimer's Disease. We know, for example, that when individuals leave simpler healthier lifestyles from other cultures and take up the lifestyles of modern America, the likelihood of dementia goes up. What are those things we do that expose us to risk of Alzheimer's? The answer is not simple. The difficulty is that the risks factors for Alzheimer's Disease are multiple, interactive and complicated. No one factor is responsible for this illness, and no one simple measure will stop it.

Let's begin with what the panel admits to be avenues for reducing the risk of Alzheimer's Disease. In their summary of results, the panel stated that "factors associated with increased risk of AD and cognitive decline were: diabetes, epsilon four allele of the apolipoprotein E gene [This is a genetic factor you cannot change], smoking, and depression." In addition, the panel stated that, " Factors showing a fairly consistent association with decreased risk of AD and cognitive decline were: cognitive engagement and physical activities." They went on to say that the benefits from addressing any one of those factors was small to moderate in terms of reducing the development of Alzheimer's or preventing cognitive decline. What they did not address was if a healthy lifestyle that imporved all of those factors in a comprehensive fashion might provide more than mere small to moderate benefit. No cardiologist would suggest that merely taking a blood pressure pill and walking around the block several times a week can eliminate a person's risk of heart disease. It is similarly nonsensical to suggest, as per Dr. Daviglus' statement, that a pill and a puzzle is the means to avoid the ever so complicated Alzheimer's Disease. Thus, even if we agree to ignore the considerable amount of data showing benefits of stress reduction, improved sleep, dietary changes, and other such measures, we must ask what benefits might result from combining the avoidance of diabetes, smoking, and depression with an increase in exercise and intellectual activity.

It is also important to realize that the method the panel used to discern what may or may not be useful to reduce the risk of Alzheimer's required them to eliminate the results of thousands of studies on the subject. They admitted that, "Some of the factors that did not show an association with AD or cognitive decline in this review may still play an influential role in late-life cognition, but there was not sufficient evidence to draw this conclusion." Certainly, the panel cannot be faulted for being stringent in their criteria for accepting scientific studies for inclusion in their review of the evidence for reducing the risk of Alzheimer's. Such stringency is what we expect of good scientific research. However, when lacking firm evidence, we physicians must rely on indications and known relationships. As only one example, the panel stated that Metabolic Syndrome could not be shown to increase the risk of Alzheimer's Disease. Metabolic syndrome is the combination of elevated blood sugar, high blood pressure, abdominal obesity, high triglycerides, and low good HDL cholesterol. The puzzling and unfortunate fact is that almost all cases of adult onset diabetes, which the panel recognized as a risk factor for Alzheimer's Disease, begin as Metabolic Syndrome. Thus, for the panel to fail to recommend that Metabolic Syndrome be diagnosed and treated as a means to reduce the risk of Alzheimer's Disease must be seen as contrary to common sense.

As another example, the panel noted that " high adherence to a Mediterranean diet is associated with lower risk of AD". However, because of one weak study to the contrary, they felt that the data was not yet strong enough to recommend it as a genuine preventative measure. If one takes into account that Mediterranean diet helps prevent diabetes, which the panel agrees is a risk factor for Alzheimer's, then the recommendation of this diet is not unreasonable.

I believe it can be said that in trying to be conservative, the panel has grossly understated our ability to avoid Alzheimer's and other forms of dementia through healthy diet, exercise, stress reduction, improvement of emotional well being, intellectual activity, good sleep, supplements, good medical care, and other comprehensive steps to improve overall health. To their credit, the panel did admit that, " Many of the exposures reviewed in this report likely do not work in isolation in their effect on risk of AD or cognitive decline. Instead, they work in combination with other factors." I myself believe that this is not a mere caveat, but rather the essence of the approach that must be taken. Dr. Daviglus is absolutely correct in saying that no mere pill or puzzle can prevent Alzheimer's Disease. However, the panel is simply wrong in stating that we have no means currently at our disposal to decrease our risk for avoiding this dreadful illness.