In a large clinical trial to determine the risks and benefits of daily low-dose aspirin in healthy older adults without previous cardiovascular events, aspirin did not prolong healthy, independent living (life free of dementia or persistent physical disability).
The group taking aspirin had an increased risk of death compared to the placebo group: 5.9 percent of participants taking aspirin and 5.2 percent taking placebo died during the study.
ASPREE is an international, randomized, double-blind, placebo-controlled trial that enrolled 19,114 older people (16,703 in Australia and 2,411 in the United States). The study began in 2010 and enrolled participants aged 70 and older; 65 was the minimum age of entry for African-American and Hispanic individuals in the United States because of their higher risk for dementia and cardiovascular disease. At study enrollment, ASPREE participants could not have dementia or a physical disability and had to be free of medical conditions requiring aspirin use. They were followed for an average of 4.7 years to determine outcomes.
So if you're an older adult, and not afflicted with dementia or cardiovascular disease, it might not be a good idea to take a daily preventive dose of aspirin.