Can Alzheimer's Be Prevented?

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Few things are as terrifying as losing one's mind. Alzheimer's disease is the most common form of dementia among the elderly and affects as many as 4.5 million Americans, according to the U.S. National Institutes of Health. It currently has no cure. But recent research offers groundbreaking insight into what causes the disease, and how researchers could reduce people's risk. Walter Kukull, director of the U.S. National Alzheimer's Coordinating Center, explains.

Q: Can Alzheimer's disease be prevented?

A: I think the short answer is that, yes, it can be prevented, but there are a number of different ways that people are working on it right now [to figure out how].

One way stems from genetics. There's a particular protein that's made in people with Alzheimer's — which is made from a protein that all of us make, the amyloid precursor protein. [In people with Alzheimer's] that precursor protein is clipped by enzymes in the wrong place, and begins to form these little toxic parts that aggregate [in the brain] and eventually form fibrils and plaques that are the main pathologic feature of Alzheimer's disease. It's not clear why this happens exactly, and a lot of people have been studying it pretty hard. It's also not clear how much of this protein needs to be formed or where it might need to be formed before clinical signs and symptoms appear.

Drug discovery work is going on right now, mostly in two directions. One is to block these enzymes that cut the precursor protein in the wrong place, so that the plaque-forming bits of the protein aren't formed. And the other is to think of ways, probably [having to do] with the immune response, to break up the aggregated protein bits once they do form.

For people who already have some of these plaques forming, there's not a lot that can be done until we get some disease-modifying therapy. Within the last few years, there have been quite a few [drugs] getting into Phase III clinical trials — that means larger trials with larger groups of people. They're not prevention trials, [but they're] just seeing whether the treatments can modify this aggregation of plaques one way or the other. There is some hope that we'll have disease-modifying therapies in the not too distant future. But I can't put an exact number on it.

There are other [ways possibly to mitigate risk] if we think about dementia generally — of which Alzheimer's is a part — that are a little controversial. A lot of the time there are vascular and metabolic diseases or processes that could somehow modify Alzheimer's pathology. The evidence that these things contribute to dementia is pretty solid, but how it works exactly with Alzheimer's disease still needs a little bit of research. [There is an association between hypertension and Alzheimer's, for example.] So if you have hypertension, treat that. Exercise is still good for a lot of different things and may provide some benefit against Alzheimer's disease, although we don't know exactly what the mechanism might be. You should probably [also treat] other metabolic conditions, like diabetes and obesity and so on. It's the usual advice, but it probably will somewhat decrease the overall occurrence of dementia.