Researchers in the US studying a large patient population have shown that use of the anti-inflammatory and painkiller ibuprofen is linked to lower risk of developing Alzheimer’s disease. Patients who used the drug for more than 5 years were 40 per cent less likely to develop the disease compared with patients who did not use that type of drug at all.
The study is the work of researchers from Boston University School of Medicine and Boston University School of Public Health, Boston, Massachusetts, and the Bedford Veterans Affairs Medical Center, Bedford, also in Massachusetts and is published online in the 6th May issue of the journal Neurology.
Previous studies have shown contradictory results about the link between use of NSAIDs and reduced risk of Alzheimer’s disease. Also, they have tended to be short and small, so the researchers in this study carried out a larger, longer term investigation.
Study author Dr Steven Vlad, with Boston University School of Medicine, said their results suggest that it is specific NSAIDs rathen than NSAIDs that are linked with reduced Alzheimer’s risk.
The object of the study was to examine the impact of long term NSAID use on risk of Alzheimer’s disease, by looking at how it suppresses the formation of Aβ1-42 amyloid, the main protein present in senile plaques in the brains of people with Alzheimer’s disease.
For the study the investigators searched records from the large US Veterans Affairs Health Care system database and found over 49,000 Alzheimer’s patients over 55 years of age and matched them to over 196,000 controls from the same population.
From the records they were able to classify the cases into seven time periods in terms of NSAID exposure: (1) no use, (2) under or equal to 1 year, (3) over 1 but less than 2 years, (4) over 2 but less than 3, (5) over 3 but less than 4, (6) over 4 but less than 5, and (7) over 5 years.
Using a statistical method called conditional logistic regression, and adjusting for potential confounders such as race and other illnesses, they looked at the statistical strength of the links between development of Alzheimer’s and various types of NSAID use: (1) any NSAID, (2) any NSAID except nonacetylated salicylates, (3) each class of NSAID, (4) each individual NSAID, and (5) NSAIDs that suppress Aβ1-42.
The results showed that:
- Longer term use of NSAIDs was linked to lower risk of developing Alzheimer’s disease compared to non-use of NSAIDs (odds ratio decreased from 0.98 for 1 year or less, to 0.76 for over 5 years).
- The risk reduction was more marked for ibuprofen (odds ratio decreased from 1.03 to 0.56 over the same period).
- For other classes of NSAID, and individual NSAIDs, the results were inconsistent.
- There was “no difference between a group of Aβ1-42-suppressing NSAIDs and others”, wrote the researchers.
The researchers concluded that:
“Long-term nonsteroidal anti-inflammatory drug (NSAID) use was protective against Alzheimer disease.”
But, they found the findings were “clearest for ibuprofen”, and that “Aβ1-42-suppressing NSAIDs did not differ from others”.
Commenting on the findings, Vlad said that:
“Some of these [NSAID] 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,” he added, and suggested that: “One reason ibuprofen may have come out so far ahead is that it is by far the most commonly used.”
The investigators were keen to point out that an observational study such as this one cannot prove that NSAID directly cause the reduction in risk. It could be something about the people that chose to use NSAIDs that drove down the risk.
These findings do not justify taking NSAIDs as a way to prevent dementia, they warned.
“Protective effects of NSAIDs on the development of Alzheimer disease.”
Vlad, Steven C., Miller, Donald R., Kowall, Neil W., Felson, David T.
Neurology 2008 70: 1672-16, published online May 2008.
Sources: Journal abstract and press release.
Written by: Catharine Paddock, PhD