Long-term use of ibuprofen and other drugs commonly used for aches and pains was associated with a lower risk of Alzheimer's disease, according to a study published in the May 6, 2008, issue of Neurology®, the medical journal of the American Academy of Neurology. Previous studies have shown conflicting results, but this is the longest study of its kind.

For the study, researchers identified 49,349 US veterans age 55 and older who developed Alzheimer's disease and 196,850 veterans without dementia. The study examined over five years of data and looked at the use of several non-steroidal anti-inflammatory drugs (NSAIDs). The veterans received medical care and prescriptions through the VA Health Care system.

The study found people who specifically used ibuprofen for more than five years were more than 40 percent less likely to develop Alzheimer's disease. Results also showed that the longer ibuprofen was used, the lower the risk for dementia. In addition, people who used certain types of NSAIDs for more than five years were 25 percent less likely to develop Alzheimer's disease than non-users.

While other NSAIDs such as indomethacin may also have been associated with lower risks, others such as celecoxib did not show any impact on dementia risk. "These results suggest that the effect may be due to specific NSAIDs rather than all NSAIDs as a class," said study author Steven Vlad, MD, with Boston University School of Medicine.

"Some of these medications taken long term decrease the risk of Alzheimer's disease, but it's very dependent on the exact drugs used. It doesn't appear that all NSAIDs decrease the risk at the same rate," said Vlad. "One reason ibuprofen may have come out so far ahead is that it is by far the most commonly used."

Observational studies such as this one must be interpreted with the understanding that they do not prove that an NSAID has a therapeutic effect. The study is subject to what is called "indication bias." That means that it might not be the NSAID use that drove the lower risk of dementia, but rather something about the people who chose to use the NSAIDs that was responsible. These findings should not be taken to mean that NSAIDs should be administered to prevent dementia.

The most common side effects of NSAIDs are nausea, vomiting, diarrhea, dizziness, constipation and headache.

The study was supported by grants from the National Institutes of Health.