In the first part of the article, Dr. Peter Buzzacott admitted that there just have not been enough studies to tell if there are either benefits or risks to taking an aspirin a day. The only study that he mentions dealt with rats that were given high doses of ASA for two days and then subjected to a hyperbaric chamber. In this single study, the rats seemed to have benefited by having to have fewer episodes of decompression illness. That is great for the rats, but not really helpful for the rest of us!
Dr. Chimiak MD, addressed some of the the other possible risks anytime someone is taking an aspirin regime, and that is the tendency for increased bleeding. Aspirin is a known anticoagulant, and can therefore make it more difficult for blood to clot. This is of concern to divers who may experience bleeding from things such as barotrauma and severe neurologic decompression illness (DCI).
When a person has bleeding from injuries such as might happen with a middle-ear or sinus barotrauma (squeeze), it might be more difficult to get the bleeding to stop if the person is taking anticoagulants, such as ASA. A greater concern is with a serious neurologic DCI, where bleeding or hemorrhage occurs. If this happens, then the outcome may be negatively affected by the presence of the aspirin or any other anticoagulant drugs.
Therefore, as with all medications and diving, consult your physician first. Then, take every precaution to avoid injuries that might lead to bleeding episodes. That means, equalize often, and take your time when descending to make sure you are experiencing no pain! Do not dive if you have congestion, or anything that might put extra stress on the blood vessels. Finally, be very conservative to avoid DCI that might lead to neurologic trauma.