Should you take a daily aspirin?
Following the results of the previous studies, many physicians assumed that providing aspirin to men and women would decrease the incidence of heart attacks. However a new study (reference 4) provides significant new information. As part of the Women's Health Sudy, 39,876 healthy women, aged 45 and above, were selected to participate in a study that provided them with 100 mg aspirin on alternate days, or a placebo, and monitored them for 10 years. Somewhat surprisingly, the women taking aspirin only had a small risk reduction that was not statistically significant: 0.91, with a Margin of Error between 0.80 to 1.03. Like in the previous studies, there was no significant reduction in death from vascular diseases (RR=0.95, Margin of Error between 0.85 and 1.06). Overall, there was a decrease in ischemic strokes - a Relative Risk of 0.76, with a margin of error between 0.63 and 0.93.
There was one subgroup of the studied women that had significantly benefitted from aspirin - those 65 years of age and older. This subgroup was composed of 10% of the study population, but had almost one third of the cardiovascular events. In this group the Relative Risk for a major cardiovascular event was 0.74 (Margin of Error 0.59 to 0.92).
Here's a summary of the comparison between the Relative Risk results:
| Men | Women | |
|---|---|---|
| Heart Attack | 0.68 (Age > 50) | 0.74 (Age > 65) |
| Ischemic Stroke | No Effect | 0.76 |
| Hemorrhagic stroke | 1.56, large error | Non-significant increase |
| Internal Bleeding | 1.22 (0.98 - 1.53) | 1.4 (1.07 - 1.83) |
| Overall Mortality | No impact | No Impact |