Aspirin does degrade over time, and it degrades faster if exposed to warm, humid air. If your bottle of aspirin has passed its expiration date or smells like vinegar, discard it. It may no longer be effective.
Preventing heart attack
Blood is made up of red and white blood cells, plasma (the liquid part), and small, sticky particles called platelets. Normally, platelets help to heal wounds by causing the blood to clot at the site of an injury. However, in people with diabetes, platelets tend to be too sticky and more likely to form clots that are not beneficial. Such clots can lead to heart attack or stroke. (Click here to find out what to do if you think you’re having a heart attack.) Regular aspirin use “thins” the blood, so that platelets are less likely to stick together and form clots.
Some recent studies have questioned how well aspirin therapy prevents heart attack in people with diabetes.
One study, published in October 2008 in the journal BMJ and called “The Prevention of Progression of Arterial Disease and Diabetes,” was conducted at the University of Dundee in Scotland. It looked at 1,276 men and women who had never had a heart attack or stroke but were at high risk because they had either Type 1 or Type 2 diabetes, were age 40 or older, and had peripheral arterial disease. The researchers wanted to see if 100 mg of aspirin daily helped prevent “cardiovascular events” (such as heart attack or stroke) in the study participants. Some of the study participants took an aspirin a day, and some took a placebo (an inactive pill). After eight years, the researchers found that the number of heart attacks and strokes was about the same in the aspirin group as it was in the placebo group.
However, the researchers noted that several earlier studies have established the effectiveness of daily aspirin in reducing the risk of another heart attack or stroke among men and women with diabetes who have already had a heart attack or stroke. They concluded that aspirin should still be given for prevention of heart attacks in people with diabetes with diagnosed cardiovascular disease.
Another recent study, published in The Journal of the American Medical Association in November 2008 and called the “Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes” trial, examined whether daily aspirin therapy prevented first cardiovascular events in Japanese people with Type 2 diabetes and no history of heart disease. In this study there were 2,539 participants, and the study lasted for about four years. At the end of the study, the re-searchers observed no significant difference in the number of first-time cardiovascular events in the two groups. But they did note that among study participants aged 65 and older, the risk of cardiovascular events decreased by 32%. Still, the researchers cautioned that the study results had to be looked at in context, and that the overall rate of initial cardiovascular events was relatively low.
The conclusions of these two studies are consistent with previous studies that have found little benefit to taking low-dose aspirin for people with diabetes who do not already have cardiovascular disease. However, some experts believe that larger studies of longer duration that use a higher dose of aspirin are needed to settle the question of whether aspirin can prevent new cardiovascular disease in people, and specifically Americans, with diabetes.
At present, two larger-scale studies of the effects of aspirin — one with locations in the United States — are recruiting individuals with diabetes to participate. It is hoped that these studies will better establish the risks and benefits of aspirin in people with diabetes at moderate to high risk of a first heart attack or stroke.