Aspirin, a commonly used medication in the US, has been widely taken by adults aged 60 or older to prevent blood clots that may lead to heart attacks or strokes. However, recent studies have raised concerns about the risks associated with aspirin therapy for older adults, particularly the increased likelihood of major bleeding. Consequently, the blanket recommendation for aspirin use has been reconsidered, with emphasis placed on its benefits for individuals who have previously experienced heart attacks or strokes.

While aspirin's association with significant bleeds like aneurysms has been studied, researchers sought to investigate whether it could also contribute to subtler forms of blood loss, potentially leading to anemia, a condition characterized by reduced oxygen levels in the blood. Anemia is a prevalent issue among the elderly population, often underestimated in comparison to heart attacks and strokes. Studies have shown that approximately 30% of adults aged 75 and older worldwide suffer from anemia, which can manifest as fatigue, cognitive difficulties, depression, and an increased risk of mortality.

A study published in the Annals of Internal Medicine examined over 18,000 adults aged 65 and older from the US and Australia. Half of the participants were administered a low daily dose of 100 milligrams of aspirin, while the other half received a placebo. The researchers monitored the participants for approximately five years, conducting yearly medical check-ups and blood tests to measure hemoglobin and ferritin levels—a protein in blood cells responsible for iron storage.

The study revealed a notable difference: adults taking aspirin were 20% more likely to develop anemia compared to those who did not take the medication. The researchers estimated that within five years, 24% of seniors in the daily aspirin group would experience anemia, compared to 20% in the placebo group. Furthermore, individuals in the aspirin group exhibited slightly lower levels of hemoglobin and ferritin, affecting their blood cells' ability to carry oxygen.

Even after adjusting the data for factors such as cancer, major bleeding incidents, age, sex, diabetes, kidney disease, and the use of nonsteroidal anti-inflammatory medications (NSAIDs), the disparity persisted. Although the study did not delve into the precise mechanisms linking aspirin to anemia, the authors propose a possible explanation. Aspirin impedes blood clotting by preventing platelets from aggregating, and it also inhibits an enzyme called Cox-1, which plays a role in maintaining the integrity of the stomach and intestinal lining. With this protective barrier compromised, small amounts of blood may leak from the gastrointestinal tract over time, leading to anemia.

The researchers highlighted that this effect was observed across various demographic groups, irrespective of their underlying health conditions. Consequently, individuals with additional risk factors for anemia, such as inflammatory diseases like arthritis or chronic renal insufficiency, should receive closer monitoring of their hemoglobin levels, especially if they are also taking aspirin.

In conclusion, the widespread use of aspirin among older adults to prevent blood clots warrants caution due to the potential risk of developing anemia. The findings of the study underscore the importance of considering individual factors and risk profiles when prescribing aspirin therapy. Healthcare providers should be vigilant in monitoring hemoglobin levels, particularly for patients with multiple risk factors and those taking aspirin alongside other medications. As research in this field continues, a more comprehensive understanding of the relationship between aspirin and anemia will emerge, enabling healthcare professionals to make informed decisions about the most suitable treatment options for their patients.