Using Aspirin Every Day May Cause Anemia in Seniors

A new study suggests regular aspirin use in older adults may pose a serious risk of anemia, adding to existing research that challenges the long-established recommendation to use aspirin as a preventative therapy for dangerous cardiac events. The results come just a year after a national independent task force updated formal recommendations in April 2022 cautioning those over the age of 60 against beginning a daily aspirin regimen.

For decades, aspirin has been used like a vitamin by a sizable portion of America’s aging population. Research as far back as the 1950s showed a daily low dose of the anti-inflammatory medication could help prevent diseases like heart attacks and stroke. Eventually, the benefits of the routine became common knowledge, and older adults added the over-the-counter medication to their pillboxes without any sort of formal physician recommendation. In 2021, 45% of Americans over the age of 75 reported taking daily low doses of aspirin. Its health benefits and low cost have made aspirin the most widely used medication in the world.

Read more: Should You Take Aspirin Every Day? Here’s What the Science Says

However, those benefits were mostly observed in studies of relatively young cohorts. In recent years, research has focused on the older populations most likely to use aspirin regularly, and has found that a daily aspirin regimen has been linked to more major bleeding events, like aneurysms, often at a rate that exceeds the risk of heart disease that aspirin use is intended to prevent.

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The new research, published June 20 in the Annals of Internal Medicine, is the first to show a risk of more minor blood-related conditions in daily aspirin users. As part of the the National Institutes of Health-funded Aspirin in Reducing Events in the Elderly (ASPREE) study, a team of researchers in the U.S. and Australia recruited more than 18,000 people over the age of 65, and gave them all either 100 mg of aspirin or a placebo pill daily for nearly five years. When accounting for other major diseases, bleeding events, and health factors represented in the group, the team found those taking aspirin were 20% more likely to be anemic than those who didn’t.

Anemia, a disorder in which the body runs low on the red blood cells required to transport oxygen throughout the body, can have several consequences in the elderly. Common anemia symptoms like fatigue, low blood pressure, and high heart rate can be extra risky for the elderly.

In the case of aspirin use, related anemia would likely be caused by slower blood loss due to aspirin’s anti-clotting effects, either via minor injury or light internal bleeding. This can also lead to serious iron deficiencies. Researchers found the participants taking aspirin also had lower levels of hemoglobin and ferritin, two important proteins that help blood cells carry oxygen. Because of this, they recommend that older adults who take aspirin—particularly those with existing chronic conditions that put them at increased risk for anemia—receive regular blood testing to ensure that their hemoglobin levels remain within a safe range.