Surprising discovery: Researchers unveil anemia risk linked to daily aspirin use in older adults

Aspirin is one of the most commonly used medications in the US.

Studies show that over 40% of adults ages 60 or older take aspirin daily to prevent dangerous blood clots that could lead to a heart attack or stroke [1]. 

In recent years, experts have backed away from blanket use of aspirin therapy for all older adults. However, studies showed that it carried an increased risk of major bleeding that most likely outweighed any benefit in preventing first heart attacks or strokes [2]. Although, it’s still recommended in some cases for people with a heart attack or stroke to prevent another.

Because aspirin can contribute to the danger of big bleeds like aneurysms, researchers wanted to know whether it might also factor in more subtle blood loss: the kind that may lead to anemia or reduced oxygen in the blood.

Anemia is another big problem in older adults, though perhaps underappreciated compared with heart attacks and strokes. Studies show that 30% of adults 75 and older worldwide are anemic, and anemia is generally tied to worse health – including fatigue, memory and thinking trouble, depression and an increased risk of death [3].

A study published Monday in the Annals of Internal Medicine followed more than 18,000 adults 65 and older from the US and Australia. Half took 100 milligrams of aspirin a day – a low dose, while the other half took a dummy pill.

Featured product offer
Bayer Aspirin Pain Reliever / Fever Reducer 100 Tabs
  • Contains 500 mg extra strenght aspirin (NSAID).
  • Coated caplets are easier to swallow.
  • Sodium and caffeine free.

The researchers followed them for about five years. Study participants had yearly doctor visits and blood tests for hemoglobin and ferritin, a protein in blood cells that stores iron [4].

They saw a slight but clear difference. Adults who took aspirin were 20% more likely to be anemic than those who didn’t. Based on their results, the researchers estimated that 24% of seniors in the daily aspirin group would develop anemia within five years, compared with 20% of those in the placebo group.

Those on aspirin regimens also had slightly lower levels of hemoglobulin and ferritin, which help blood cells carry oxygen.

The difference remained even when the researchers adjusted their data to account for cancer and major bleeding events during the study and for other differences between the participants like age, sex, diabetes, kidney disease and nonsteroidal anti-inflammatory medications or NSAIDs.

The study didn’t look at how aspirin may contribute to anemia, but the authors know how it might happen. Aspirin makes blood clots harder to form because it keeps platelets from sticking together.

It also blocks an enzyme called Cox-1, which is important for maintaining the lining of the stomach and intestines. With this protective barrier damaged, it’s easier for small amounts of blood to leak out of the gut over time, eventually causing anemia.

The researchers wrote that because they saw this effect across many different groups, regardless of their underlying health, it’s likely to be a more significant concern for people with other anemia risks, such as inflammatory diseases like arthritis or chronic renal insufficiency.

They say doctors should consider monitoring their patients’ hemoglobin levels more closely if they have multiple risk factors, including aspirin use.

Featured product offer
Time Cap Labs Aspirin 1000 Enteric Safety Coated
  • Contains 325 mg of aspirin, ideal for individuals who follow a daily aspirin routine.
  • Low dose generic aspirin tablets, 1000 coated tablets per bottle.
  • Coated aspirin dissolves in the small intestine, not the stomach.


Photograph: DragonImages/Envato
The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.