A low daily dose of aspirin does not reduce the risk of dementia-related thinking and memory problems or slow the rate of cognitive decline, according to a large study.

Aspirin has anti-inflammatory properties and can thin the blood. Some evidence has suggested that it may also be beneficial to the brain, reducing the risk of dementia.

The current study investigated outcomes in about 19,000 older adults who initially had no dementia or heart disease. Half were given daily 100-milligram low-dose aspirin and all underwent cognitive testing. Participants were followed for 4.7 years on average, with annual physical exams.

The risk of developing mild cognitive impairment, dementia, or probable Alzheimer’s disease was no different between those who took the aspirin and the cohort given a placebo, reported Joanne Ryan, Ph.D., from Monash University, Australia. There was also no difference found in the rate of cognitive change over time.

The researchers plan to study the effect of daily aspirin over a longer time period. They also caution that because participants were relatively healthy, they may not have benefited from aspirin as much as the general population might.

Full findings were published online in Neurology.