May 26, 2010

Say It Isn't So

My very first post on "Perspectives on Aging" dealt with dementia. I reported on a study that found exercise could decrease the risk of becoming demented. Since then I've blogged about dementia in general and Alzheimer's disease in particular 5 more times without a whole lot of encouraging news. The bad news just got a little worse: a recent National Institutes of Health "state-of-the-science" conference concluded that although a few tantalizing studies have suggested that exercise or social engagement or crossword puzzles could fend off dementia, a systematic evaluation fails to confirm these findings.

Dementia is unfortunately a very common condition which more and more people are developing as the population ages. At last count, 5.4 million Americans had Alzheimer's disease. Medications to treat Alzheimer's are mediocre-the most positive statement the American Psychiatric Association could make in a recent practice guideline for the most effective drugs, the cholinesterase inhibitors, is that they have a "modest" effect in a "substantial minority" of patients. Hardly a ringing endorsement. The antipsychotics, drugs often prescribed to treat the behavioral manifestations of dementia, have been associated with a small increased risk of death-which might be an acceptable price to pay if they worked, but they rarely do. Despite the scientific progress in the understanding of how Alzheimer's disease develops-and we know infinitely more today than Alois Alzheimer did in 1906 when he peered through the microscope and found plaques and tangles outside and inside (respectively) the neurons of his former patient, Auguste D-the prognosis for effective intervention is poor.

The new NIH report is very blunt: "There is currently no evidence considered to be of even moderate scientific quality supporting the association of any modifiable factor...with reduced risk of Alzheimer's disease." By "modifiable factor," the report means nutritional supplements, dietary factors, medications, social factors, economic factors, medical conditions, toxins, and other environmental exposures.

But perhaps we are looking at the problem the wrong way. In geriatrics, it's actually quite rare to find a single intervention that can prevent a complex condition, what geriatricians call a syndrome. A growing literature advocates a multi-pronged attack on this sort of problem. The risk of falling, for example, can be lowered somewhere between 25 and 39% of a combination of maneuvers, including review of medications and gait and balance training. The risk of developing delirium (an acute confusional state) in the hospital can be lowered by a third with a combination of 6 interventions, including avoidance of sleeping pills and providing patients with their glasses and hearing aids.

Maybe, just maybe, the risk of dementia can be lowered by maintaining contacts with other people, participating in social activities, playing music, exercising, and taking medication to treat high blood pressure. Each alone may have an extremely modest effect, but together, they just might make a difference.

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