Risks of Low-Dose Aspirin Offset Benefits in Younger Women

(HealthDay News) — For women aged younger than 65 years, taking low-dose aspirin for years lowers their risks for heart attack, stroke and colorectal cancer by a small amount, but the benefit is countered by an increase in the risk for major gastrointestinal bleeding, according to a study published in Heart.

The findings are based on a clinical trial of 27,939 women who were largely healthy and relatively young — about 55 years old, on average, at the start of the study. They were randomly assigned to take low-dose (100 mg) aspirin or placebo pills every other day. 

Over the next 15 years, about 11% of the women either developed cancer, suffered a heart attack or stroke, or died of cardiovascular (CV) causes.

Women who had taken aspirin saw a small decrease in their odds of CVD or colorectal cancer — but at the expense of an increase in the risk for gastrointestinal bleeding, the researchers found. That expense was clear among women younger than 65. 

The researchers estimate that for every 133 women on aspirin for 15 years, one would suffer a major gastrointestinal bleeding episode — serious enough to warrant a hospital stay. And one out of 29 women would have less serious problems: a stomach ulcer or slight bleeding in the digestive tract. 

By comparison, 709 women would have to take aspirin to prevent one case of colorectal cancer, and 371 would have to regularly take the drug to ward off one CV complication.

The picture changed, however, as women grew older. Among those aged 65 years and older, 29 would need to take aspirin, long term, to prevent one case of CVD or cancer.

“In conclusion, when balancing combined long-period [acetyl salicylic acid] benefits on CVD and cancer with its harmful effects, taking into account the individual risk profile for each investigated outcome, these [Women’s Health Study] results support no treatment indications with alternate-day low-dose aspirin in healthy women,” wrote the authors of an accompanying editorial.

Nevertheless, they noted that further research may help identify those who would benefit from low-dose aspirin.


  1. van Kruijsdijk RCM et al. Heart. 2014;doi:10.1136/heartjnl-2014-306342.
  2. Ferrario MM and Veronesi G. Heart. 2014;doi:10.1136/heartjnl-2014-306770.