A recent study from the Mayo Clinic, published in the Journal of the National Cancer Institute (JNCI, vol. 99, p. 825, 2007), looked at the relationship between the use of aspirin and non-aspirin NSAID (non steroidal anti-inflammatory drugs) in postmenopausal women and the incidence of death from cancer, heart disease, and death from any cause.
How the study was done
The investigators studied data on about 22,500 women who were enrolled in the Iowa Women’s Health Study, a long-term health study of women living in Iowa. Starting in 1986, the women completed surveys periodically about their medical history, diet, physical activity, smoking, and other factors every year until 1992. In that year, the women also reported their use of aspirin and nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. They were then followed, without filling out additional questionnaires, until 2002.
And the results were…
- Women who took aspirin were 13% less likely to die of cancer.
- They were 25% less likely to die of heart disease.
- They were 18% less likely to die of any cause during the study.
- Non-aspirin NSAID had no effect on mortality.
What’s wrong with this picture?
Plenty. Let me count:
1. The study was observational; such studies are fraught with problems and are not very reliable. For instance, the investigators did not study the effect of aspirin by giving the drug and following them for the study period (known as a prospective study). They got their data from a questionnaire filled out by the participants.
2. The study started in 1986 and ended in 2002—16 years in duration. And only at one point in time (1992) were the participants asked to recall their aspirin use. The quality of such recall has been shown in several studies as flawed.
3. The questionnaire did not ask about the frequency and dose of the aspirin. And even if they did, such data would have been of questionable utility. Would you trust your own recollection of your aspirin intake several years back? Or even the prior 6 months?
4. The study was restricted to postmenopausal women, mostly white. Does this finding extend to other population groups?
5. Only aspirin had an effect on mortality. Non-aspirin NSAID, such as Advil, Motrin, and Aleve, had no effect. This finding is in conflict with other studies showing non-aspirin NSAID having a survival benefit similar to aspirin. Both types of drugs have a similar mode of action; they are anti-inflammatory drugs, targeting the same metabolic pathway (prostaglandin synthesis). If, however, this observation stands up to repeat studies, it would be a great contribution, which may uncover some subtle differences of clinical importance between aspirin and other NSAID.
Should you start taking aspirin?
Obviously, this is at best an incomplete study. On this basis alone, it would be inadvisable to start taking aspirin on a daily basis. Admittedly, other studies suggest that daily aspirin is beneficial, to a small degree, in the prevention of breast cancer and colon cancer, as well as heart disease.
But consider these two facts:
- Aspirin is not harmless. It can cause all kinds of stomach problems, like gastritis (inflammation of the lining of the stomach) and ulcer. It can also cause bleeding problems, including hemorrhagic (bleeding) stroke.
- Why take medicine for a 13% reduction in cancer mortality when you can eat well (five helpings of fruits and vegetables a day), exercise (30 minutes walk, six times a week), and cut your risk of death from breast cancer by 50%! See my earlier post, “Women with breast cancer can lower their risk of dying by 50%.” The same type of protection has been shown for colon cancer, and for heart disease.
As far as I am concerned, the choice is obvious.