Taking aspirin daily can significantly reduce the risk of developing major cancers of the digestive tract, ie bowel, stomach and oesophagus, besides heart attacks and strokes it is known to prevent.
New research from Queen Mary University of London reveals that taking aspirin for 10 years could cut bowel cancer cases by around 35% and deaths by 40%. Rates of oesophageal and stomach cancers were cut by 30% and deaths from these cancers by 35-50%.
"Our study shows that if everyone aged between 50-65 started taking aspirin daily for at least 10 years, there would be a 9% reduction in the number of cancers, strokes and heart attacks overall in men and around 7% in women.
"The total number of deaths from any cause would also be lower, by about 4% over a 20-year period. The benefits of aspirin use would be most visible in the reduction in deaths due to cancer," said Professor Jack Cuzick, Queen Mary University of London, lead author of the study.
The scientists reviewed all available evidence from many studies and trials assessing benefits and harm from consuming aspirin. The conclusions of the study, funded by Cancer Research UK among others, are published in the journal Annals of Oncology.
The dosage and duration are important if one is to reap the benefits of aspirin, the study found. People need to start taking a daily dose of 75-100 mg for at least five years and probably 10 years between the ages of 50 and 65.
No benefit was seen whilst taking aspirin for the first three years, and death rates were only reduced after five years. It is not clear whether taking aspirin for longer than 10 years will result in greater benefits.
However, the research also warns against the harmful effects of aspirin which include bleeding from the digestive tract, the risk of which for those under 70 taking aspirin daily for 10 years goes up to 5%.
The other side effect of aspirin use is peptic ulcer, the risk of which increases by 30-60%.
While studies have shown that aspirin reduces risk of heart attacks, its efficacy in those who have never had heart problems is unsure.
According to the US Food and Drug Administration, in these people, aspirin provides no benefits and puts them at risk for side effects such as dangerous bleeding in the brain or stomach.