May 29 -- WEDNESDAY, May 28 (HealthDay News) -- The painkillers called non-steroidal anti-inflammatory drugs (NSAIDs) appear to reduce the risk of developing Alzheimer's disease, but no one medication in the class works better than the others, a new analysis finds.
Data from the study, the largest of its kind, contradicts some previous studies that found that ibuprofen might exceed others in its class when it comes to preventing this type of dementia. Besides ibuprofen, other types of NSAIDs include naproxen and aspirin.
But the bottom line, the study authors said, is that the findings don't support the use of NSAIDs to prevent or treat Alzheimer's, at least not yet anyway.
"You do not want to take NSAIDs to prevent against Alzheimer's," said study senior author Peter P. Zandi, an assistant professor of mental health at Johns Hopkins Bloomberg School of Public Health in Baltimore. "We don't have any sufficient data to make any recommendations like that, but we need to figure out what's going on so we can better understand the explanation for this finding."
Added Dr. Gary Kennedy, head of geriatric psychiatry at Montefiore Medical Center in New York City: "The reader should be aware that what was conveyed [by the NSAIDs in the study] was a fraction of a benefit."
The findings are published in the May 28 online issue of Neurology.
While some observational studies have indicated that NSAIDs -- especially ibuprofen -- might lower the risk of developing Alzheimer's, a recent large, randomized, controlled trial found no effect in treating the disease. Meanwhile, some basic science studies have indicated that certain NSAIDs might reduce production of a peptide fragment called A beta 42, which is a key component of the plaques that develop in the brains of people with Alzheimer's.
The researchers behind the new study combined data from six prospective studies involving 13,499 people to compare the group of NSAIDs known as selective A beta-lowering agents (SALAs) to non-SALA NSAIDs. SALAs have been found to lower A beta 42 levels.
Overall, people who regularly took NSAIDs had a 23 percent lower risk of developing Alzheimer's. But there didn't appear to be any difference in the effectiveness of the different types of NSAIDs.
And ibuprofen, a commonly used SALA, was no more or less effective than naproxen, a commonly used non-SALA, Zandi said.
The findings do cast doubt on the theory that NSAIDs may help prevent Alzheimer's by reducing production of A beta 42, he said.
"That leaves a conundrum, a scientific mystery," Zandi said. "What's very clear is that observational data is very consistent, that there is a reduction in risk among people using NSAIDs, so there's something going on."
What exactly is going on, however, is unclear.
"The question of anti-inflammatory drugs being used as a protective mechanism against Alzheimer's has been investigated for over a decade now," said Maria Carrillo, director of medical and scientific relations at the Alzheimer's Association in Chicago. "We know that there have been some controversial results out there, so currently what we also know is that they [NSAIDs] are not approved for the treatment or prevention of Alzheimer's disease. The Alzheimer's Association does not recommend you take NSAIDs on a daily basis because there are a lot of side effects... The jury is still out on whether NSAIDs can be protective against Alzheimer's."
Visit the Alzheimer's Association for more on this condition.
SOURCES: Peter P. Zandi, Ph.D., assistant professor, mental health, Johns Hopkins Bloomberg School of Public Health, Baltimore; Maria Carrillo, Ph.D., director, medical and scientific relations, Alzheimer's Association, Chicago; Gary J. Kennedy, M.D., director, geriatric psychiatry, Montefiore Medical Center, New York City; May 28, 2008, Neurology, online