The benefits of a daily baby aspirin may be offset by bleeding risks for people over 70, according to Australian researchers.

Elderly people are at greater risk of experiencing adverse drug reactions, noted the researchers in the Online First edition of the British Medical Journal. But to date most clinical trials of aspirin therapy’s effect on cardiovascular events are conducted on middle-aged participants.

For the study, researchers considered the pros and cons of low-dose aspirin, which are recommended daily to prevent heart attacks and stroke.

They conducted a mathematical model based on clinical trial data and demographics in a theoretical group of 20,000 people aged 70 to 74. The researchers “followed” the virtual participants through death or until the age of 100.

The model suggested that low-dose aspirin therapy would prevent 389 heart attacks and 19 strokes in elderly men and 321 heart attacks and 35 strokes in women. Also, there would be nearly 499 incidents of gastric bleeding in men and 572 cases in women. Also, more than 130 men and women would suffer bleeding in the brain as a result of the aspirin therapy,investigators found.