Could humble aspirin help prevent Alzheimer disease? Research in genetically modified mice on aspirin suggests that the answer might be yes (Journal of Neuroscience, July, 2018).
How Scientists Studied Mice on Aspirin:
These mice easily develop plaques in the brain that mimic Alzheimer’s disease. When the mice were given low doses of aspirin, they developed less amyloid plaque.
The experiment demonstrated that aspirin increased the activity of a protein that helps the brain get rid of waste. In addition, lysosomes that are also essential for waste removal became more active in the mice on aspirin.
People are not mice, and research in mice should be considered preliminary. On the other hand, epidemiological research suggests that low-dose aspirin might protect patients at high risk for dementia, such as those with type 2 diabetes. Results from 16 studies with more than 200,000 participants suggest that those taking nonsteroidal anti-inflammatory drugs (NSAIDs) were less likely to develop Alzheimer disease (Frontiers in Aging Neuroscience, March 28, 2018). Scientists consider aspirin an NSAID although it differs from them in a few ways. The most notable is that aspirin has cardiovascular benefits, while other NSAIDs increase cardiovascular risk.
Cardiovascular Benefits of Aspirin:
The lowly aspirin has been around for more than 100 years, but scientists continue to debate its benefits and risks. An analysis of nine randomized, controlled trials involving more than 100,000 participants found that aspirin reduces the risk of cardiovascular complications and death (American Journal of Medicine, July, 2011).
Despite this good news, aspirin appears to increase the risk of bleeding strokes and bleeding ulcers. Weighing the benefits against such risks suggests that no one should embark on long-term aspirin therapy without medical supervision. That would be true whether one were taking it for preventing heart attacks and strokes or for reducing the chance of developing dementia.
How Much Aspirin Might Make a Difference?
Few studies have examined the possibility that aspirin could help anyone, mouse or man, avoid Alzheimer disease. A retrospective population-based (epidemiological) study in Taiwan found that people taking low-dose aspirin had a lower chance of an Alzheimer diagnosis during the eight years (Journal of Diabetes Research, Oct. 27, 2016). The individuals in this study had type 2 diabetes, which increased their likelihood of cognitive difficulties (Experimental Gerontology, Sep. 2003). The investigators found that the appropriate daily dose was around 40 mg of aspirin. That is roughly half the lowest dose available in the US (81 mg). We don’t know whether taking an 81 mg aspirin pill every other day would offer protection similar to that observed in Taiwan.
A Canadian study identified two simple tests that can identify people at risk for dementia (American Journal of Alzheimer’s Disease and Other Dementias, Nov. 2016). One is a test that asks people to copy pentagons. The other is a written subtest of the commonly-used Mini Mental State Examination. People taking aspirin or other salicylates were less likely to be diagnosed with dementia, even if they scored low on these two tests. This research also hints that aspirin may help protect people from Alzheimer disease.
There are many other factors that might prove protective. As a result, you may be interested in listening to our latest interview with Dr. Dale Bredesen, Professor of Neurology at UCLA. It is Show 1092: How Can You Overcome Alzheimer Disease?