Observational studies suggest that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) may prevent the development of Alzheimer's disease, but it is not clear if the benefit is a class effect or limited to specific agents. The role of aspirin has not been studied. Etminan and colleagues studied the risk of Alzheimer's disease in patients who use NSAIDs, including aspirin.

The authors used electronic databases and other sources to identify studies that associated the development of Alzheimer's disease or dementia with exposure to NSAIDs. Trials of other analgesics and studies of vascular dementia were excluded. All studies were reviewed independently by two researchers. Of the 15 studies identified, nine (six cohort and three case-control studies) related NSAID use to risk of Alzheimer's disease. The cohort studies included a total of 13,211 participants, and the relative risk for Alzheimer's disease in NSAID users was 0.84 (95 percent confidence interval [CI], 0.54 to 1.05). The case-control studies included a total of 1,443 participants; the relative risk for Alzheimer's disease in NSAID users was 0.62 (95 percent CI, 0.45 to 0.82). The authors conclude that the overall relative risk in NSAID users is 0.72 (95 percent CI, 0.56 to 0.94). In the five cohort and three case-control studies of aspirin use, the pooled relative risk was 0.87 (95 percent CI, 0.70 to 1.07).

The authors conclude that studies show a consistent reduction in risk of Alzheimer's disease in patients who use NSAIDs, with greater benefit related to longer duration of use. Although aspirin also may have a protective effect, the evidence for this agent is not as robust as that for NSAIDs.

editor's note: One of our most important roles as physicians is to interpret studies, or more accurately the media reports of research studies, for our patients. In this case, irresponsible reporting could lead elderly patients to take NSAIDs in the hope of preventing dementia. Careful reading of this report shows that the evidence is not completely conclusive and is a long way from being clinically applicable. Much remains to be done to identify the specific agents with the greatest protective effect, the optimal prophylactic dosage, and the patients most likely to benefit. We already have a significant problem with gastrointestinal bleeding and other complications of NSAID therapy in elderly patients. While pursuing the hope of preventing dementia, we must be careful to protect patients from the well-known adverse effects of NSAIDs.—a.d.w.