In May 2007, the same group of researchers published findings that Celebrex and naproxen did not prevent Alzheimer's disease.
For the new study, 2,117 men and women over the age of 70 with a family history of Alzheimer's disease were randomly assigned to receive 200 milligrams of Celebrex twice a day, 220 milligrams of naproxen twice a day, or a placebo. Participants did not have a diagnosis of Alzheimer's, other dementias or mild cognitive impairment at the March 2001, start of the trial.
The participants' cognitive function was tested annually, but therapy was stopped in December 2004 because another study had reported an increased risk of cardiovascular problems in people taking Celebrex.
Analysis of this trial found that people taking naproxen had lower overall scores on measures of cognitive function than did men and women taking the placebo. Individuals taking naproxen or Celebrex had lower scores on a specific mental exam than did those taking a placebo.
The differences in results between this trial and previous research may have to do with the design of the study, or the results here may apply only to Celebrex and naproxen and not to other anti-inflammatory drugs such as ibuprofen, the researchers said. Or NSAIDs may only confer protection when given much earlier.
"This is speculative but there is increasing evidence that it may be a matter of timing, so by the time older adults take these drugs, if there is a protective effect, it may be past that time," Morris explained.
At this point, however, experts don't know what the best time would be to start the drugs.
"Increasingly we see that if we're going to want to understand how the process of Alzheimer's disease begins in the brain, we cannot limit our studies simply to older adults," Morris said. "We have to begin to study people even in middle age because the disease process may have its origins decades before people actually develop it."
Dr. Gary Kennedy is director of geriatric psychiatry at Montefiore Medical Center in New York City. Regarding this particular area of anti-inflammatory research as it pertains to cognitive problems, he said, "It's not strike three, but it's strike two for sure. The inflammatory model was a reasonable shot to begin with, but it was a long shot. [Inflammation] may be a side effect."
More information
There's more on cognitive decline at the Alzheimer's Association.
