Baby Aspirin: Benefits and Hazards
Did you know that nearly 50% of Americans over 65 years of age take a baby aspirin every day? These people or their physicians have bought into the belief that low dose aspirin can reduce a person’s risk of a cardiovascular event, stroke, and/or cancer. But can it? And how would it work? Well, not by preventing pain!
Aspirin is the common name for acetylsalicylic acid, a substance modified from a chemical derived from Willow and Birch trees (salicin). The fever-reducing and pain-relieving properties of the extract were referenced by Hippocrates around about 5 B.C! Scientists figured out how it works in the 70′s–aspirin irreversibly binds to the enzymes COX-1 and COX-2, and prevents the synthesis of a group of chemical messengers or “words” (prostaglandins or PGs).
In the language of the body, the meaning of the word “PG” to a nerve fiber is “turn up the volume.” The result is that, in the presence of PGs, pain is amplified. When aspirin prevents their synthesis, the pain is dulled.
The problem is that, in the chemical language of cells, the meaning of a word differs depending on its context. In human terms, “You are pretty,” means something very different from, “You are pretty ugly.” So it is with PGs. A benefit is that, in the context of the hypothalamus (our thermostat), PG means “turn up the temperature,” and aspirin’s inhibition of PG formation will prevent fever. In the context of a blood-clotting platelet, PG means “clot.” Since aspirin hampers action of the enzyme that makes PGs, aspirin prevents clotting. And because the binding is irreversible, the effect should last–at least until the platelets or blood-clotting cells are replaced (5-10 days).
Therefore, logic suggests that aspirin should mitigate against heart attacks and strokes. And some studies suggest it does. However, other peer-reviewed papers show that aspirin is only beneficial in those who have had a previous cardiovascular event. Still others appear to say that the health risks engendered by taking a daily baby aspirin, certainly by people under 60 and without previous heart disease or diabetes, outweigh the benefits.
What about the claim that aspirin prevents cancer? A May 2012 meta-analysis of studies published over a period of 20 years showed that long-term use of aspirin may reduce “the long-term risk of several cancers and the risk of distant metastasis.” Hopeful. The trouble is that this work came on the heels of a meta-analysis published in February 2012 that claimed aspirin reduces neither cardiovascular death in those without previous risk factors nor cancer mortality. This claim was confirmed in June 2012 by a study conducted in 1000 people that showed that aspirin does not reduce cancer mortality. So, should we pop our daily pill or not?
As always, it is important to balance the potential benefits of any drug against the risks. Time to consider those pesky side effects. After all, since we make PGs, it stands to reason that they do have beneficial functions and that inhibition of their synthesis might cause unwanted side effects. One such function of PGs is to keep the stomach lining thick–necessary because the contents are highly acidic. Therefore, lack of PGs causes a common side effect of aspirin–gastrointestinal upset. Similarly, inhibiting the beneficial function of PGs in mediating blood clotting is not so good if a person is hurt in some way. In fact, Berger et al. published that a daily low dose aspirin could increase one’s chances of a major bleed by over 50%.
So, is aspirin a wonder drug? No. Remember the AITSE Bunk Detecting Principles. If it sounds like snake oil… Should everyone take their daily dose of baby aspirin? Probably not, especially not if they have not had a previous cardiovascular event. But remember, AITSE’s purpose is to provide the public with information, not to give medical advice. Its goal is that you, in cooperation with your physician, will be empowered to make your own informed decisions. And if we have helped you do that, please consider helping us by clicking on the donate button above.