Benefits & Risks of Aspirin

The Benefits

1. It could lower cancer risk.

The three new cancer studies support long-term daily aspirin use. Overall, researchers found that aspirin reduces the risk of dying from cancer by 15 percent—with notable benefits seen within three years for those taking a high dose (more than 300 mg a day) and within five years for low doses (less than 300 mg a day). Long-term use was particularly striking. After five years of regular use, risk of dying from cancer dropped by 37 percent.

Aspirin benefits were most strong with daily use or usage three to six times a week, and were less clear-cut for use only once or twice a week. The research shows "quite convincingly" that aspirin reduces cancer incidence and death ... with an apparent delayed effect," according to a commentary published alongside the new studies.

2. It may even lower risk for breast cancer.

Aspirin may lower a woman's risk of breast cancer recurrence, or possibly even its development. A 2010 report based on data from the Nurses' Health Study suggested that women who had breast cancer and took a low-dose aspirin two to five times weekly were 71 percent less likely to have a deadly recurrence than those who took little or no aspirin. And a research review published in 2008 in the Journal of the National Cancer Institute found a 13 percent relative risk reduction in women who used aspirin regularly, compared with those who did not. The findings found an overall reduced risk of 12 percent for regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) in general. Previous research on breast cancer risk and NSAID use had shown conflicting results.

3. It could help during pregnancy.

A research review published in the Lancet in 2007 suggested that pregnant women who took aspirin or other antiplatelet drugs were 10 percent less likely to develop pre-eclampsia, which involves high blood pressure and potentially serious complications for mother and fetus. Aspirin therapy during pregnancy should definitely be discussed with an obstetrician.

4. There is some hope for Alzheimer's protection.

Research has been inconclusive, but a 2008 review published in Neurology found that people who used aspirin had a 13 percent lower risk of developing Alzheimer's. The study added to an ongoing debate about whether certain types of NSAIDs—say, ibuprofen versus aspirin—were more beneficial.

5. It may help prevent strokes—unless you also take ibuprofen.

A small study published in 2008 in the Journal of Clinical Pharmacology found that stroke patients who took daily aspirin to prevent another stroke and also took ibuprofen—say, for their arthritis—reaped no antiplatelet benefit. After a patient stopped the ibuprofen, the aspirin became effective. The Food and Drug Administration warns that aspirin's benefits may be diminished by ibuprofen use.

6. It may protect against Parkinson's disease.

A 2007 study published in Neurology suggests that women who used aspirin regularly (defined as two or more times a week for at least a month at any point in their lives) may be 40 percent less likely to develop the disease.

7. It may prevent asthma in middle-aged women.

A 2008 study published in Thorax found that women 45 and older who took 100 mg of aspirin every other day were 10 percent less likely to develop asthma over the next decade than women given a placebo. The study authors noted that aspirin could exacerbate symptoms in about 10 percent of people already diagnosed with asthma.

The Risks

8. It may throw off test results for prostate cancer.

In a 2008 issue of the journal Cancer, researchers reported that men who used aspirin and other NSAIDs regularly had about 10 percent lower levels of prostate-specific antigens. The researchers suggest this may hinder the detection of prostate cancer in regular aspirin users.

9. It may increase the risk of hearing loss.

In 2010, researchers reported in the American Journal of Medicine that regular use of aspirin—at least twice weekly—upped the risk of hearing loss by 12 percent in men. Those younger than 50 had a 33 percent increased risk of hearing loss. Use of other NSAIDss or acetaminophen also increased the risk of hearing loss.