Aspirin is widely prescribed to improve our heart health in these obese and sedentary times. People who are at the highest risk of problems are those who have already had a heart attack or some types of stroke. Aspirin for these people is proven to reduce the likelihood of another heart attack or stroke and to increase life expectancy. However, these benefits come with costs, which explains why we’re not all taking it.
Aspirin at a low dose (75mg/day in the UK; 81mg/day in the USA; similar doses elsewhere), known as baby aspirin, thins the blood. In more scientific terms, it reduces the ability of platelets to form clots. Blood clots are the cause of heart attacks and the majority of strokes, two things we hope to prevent by taking aspirin. On the other hand, your body must be able to form a clot when it needs to otherwise we bruise and bleed.
It gets worse: aspirin interferes with a chain of events which give protection to the stomach from its own acid. The stomach lining becomes less well protected, and the acid begins to digest the stomach itself, forming ulcers. Sometimes ulcers burn down and hit blood vessels, causing torrential bleeding. Meanwhile, the aspirin has also slowed down the clotting process which would limit the bleeding. This happened to my patient and she could easily have died.
My patient was taking several 300mg aspirin tablets per week, not prescribed by a doctor, because she was afraid of having a stroke like her mother. She also started drinking a glass of wine a day a few years ago because she had heard this was good for cardiovascular health, but her habit had crept up to a bottle of wine a day. A glass of wine a day may have little benefit, but a bottle of wine a day can only harm you.
Small amounts of alcohol and baby aspirin show good evidence for their benefit for people who have been affected by strokes and heart attacks, but the evidence for people who have not yet suffered these problems is difficult. In the US, people at high risk (e.g. smokers with diabetes) are given aspirin; whereas in the UK, the advice was changed a few years ago. Even with low dose aspirin, there is a risk of bleeding, and we must be sure that we do not replace heart attacks with dangerous bleeding from stomach ulcers.
Painstaking science goes into proving that medicines are safe and effective, but the balance of risk and benefit can be a fine one. Every day doctors are faced with the problem of weighing evidence from populations, and applying it to individuals.
For your health, weigh yourself; let doctors weigh the evidence.