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Reconciling Disparate Studies of Alzheimer's and Anti-Inflammatory Pills
> 5/13/2008 1:50:34 PM

Millions of Americans take non-steroidal anti-inflammatory drugs (NSAIDs), either for specific maladies or for daily preventative care. This latter reason is often encouraged by doctors, but it has not yet been established exactly what cognitive benefits NSAIDs can confer. Last week, we wrote about a massive - 250,000 subject - study by Dr. Steven Vlad that found that NSAIDs reduce the risk of Alzheimer's Disease (AD) by an average of 25%. Yet, this week newspapers are flooded with reports on a new study by Dr. Barbara Martin that failed to find a benefit to NSAIDs. Some may be justifiably confused by these seeming contradictions, but this can be fully understood as a proper stepping stone on the customarily winding path of scientific enquiry.

As we pointed out in our previous article, the 25% number found by Dr. Vlad did not tell the whole story. Looking only at the average, you would miss the crucial fact that only some of the NSAIDs, like ibuprofen and indomethacin, confer benefits while others, like celecoxib, offer no protection. This gets to the heart of the divergent results from these two studies, because Dr. Martin chose to only test celecoxib and naproxen.

Dr. Martin set up a rigorous double-blind placebo study rather than relying on retrospective analysis like Dr. Vlad. This has the advantage of limiting confounding factors, but it also places inherent practical limitations on the size of the study, resulting in a subject pool only 1/10th the size of Dr. Vlad's. Dr. Martin began administering one of two NSAIDs to elderly subjects before they showed any signs of AD. Four years later, she took account of how many of these subjects had developed AD over the course of the study. She found no benefit from the two NSAIDs that she chose to administer to the experimental group, and actually reported a small but possibly significant decline in cognitive function in naproxen users.

Double-blind studies are the sort of research that we need, but we must remember that Dr. Martin's work is only one part of a large puzzle that researchers must start putting together. Every NSAID should be investigated for its effect on AD so that patients can decide which pills to take. On a more theoretical level, separating the protective from the ineffective may also give scientists a better understanding of the connection between inflammation and AD.

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