A recent study contradicts earlier observations that painkillers such as ibuprofen or naproxen, classified as non-steroidal anti-inflammatory drugs or NSAIDS, appear to prevent Alzheimer’s dementia (AD).

At best, NSAIDS may delay its onset, according to the report.

“The NSAIDs-AD relationship has been evaluated in more than 30 observational studies,” the authors write. Most of these studies found that NSAIDS have a preventative effect on Alzheimer’s disease.

For the current study, Dr. John C. S. Breitner, at the University of Washington School of Medicine in Seattle, and colleagues analyzed NSAID use and development of dementia in 2,736 members of a large local health care plan who were free of dementia at enrollment.

Screening and exams for dementia started in 1994, with biennial follow-ups continuing for as long as 12 years.

Using pharmacy records, the investigators identified 351 subjects with a history of heavy NSAID use at enrollment and an additional 107 who became heavy users during follow-up.

Dementia developed in 476 subjects, including 356 classified as having Alzheimer’s dementia. Average age at the onset of dementia was roughly 83 years.

“Contrary to the hypothesis that NSAIDs protect against AD, pharmacy-defined heavy NSAID users showed increased incidence of dementia and AD,” the researchers report in the medical journal Neurology. These patients were 66 percent more likely to develop dementia and 57 percent more likely to develop Alzheimer’s disease.

One explanation for the difference between earlier studies and these results could be that AD is delayed in NSAID users. If NSAIDs do delay the onset of AD, Breitner pointed out, “it would follow that studies looking at younger people who use NSAIDs would show fewer cases of Alzheimer’s, while in groups of older people there might be more cases, including those that would have occurred earlier if they had not been delayed.”

Indeed, Breitner pointed out in a press release from the publishers of the journal that “our participants were older.”

Nonetheless, he concluded, “We must not ignore the fundamental finding, which is an increase in the risk of dementia in the NSAID users. We need further research to understand that result more clearly.”

SOURCE: Neurology, online April 22, 2009.