Boston, MA - A new report from the Framingham Offspring Study adds to the understanding of how alcohol can act as an anticoagulant [1]. It seems that it affects both platelet aggregation and activation, Dr Kenneth J Mukamal (Beth Israel Deaconess Medical Center, Boston, MA) and colleagues have discovered.

They report their findings in the October 2005 issue of Alcoholism: Clinical and Experimental Research. "By itself, I'm not sure that this research will change clinical practice," Mukamal told heartwire."But it should remind doctors to ask patients presenting with acute myocardial infarction, 'When was the last time you had a drink?' This is something doctors tend to forget about."

If someone has been drinking in the few hours before an event and then receives a fibrinolytic, for example, "you could change a stable situation into an unstable one, with an increased risk of a bleeding stroke," Mukamal cautions.

It is known that moderate drinkers have lower rates of myocardial infarction than abstainers, Mukamal and colleagues point out. "But the mechanisms that mediate this association remain incompletely understood."

It has been shown that alcohol has a null effect on coronary artery calcification, Mukamal explained to heartwire, so it appears that moderate alcohol intake is somehow preventing clots. Previous studies have demonstrated that alcohol affects platelet aggregation, but this new work is the first to show that it also reduces activation of platelets, he notes.

Mukamal and colleagues studied adults enrolled in the Framingham Offspring Study and examined measures of both platelet activation and aggregation among women and men. Previous studies in this field have examined men primarily, Mukamal says.

In 2000 participants they found that moderate drinkers (three to six drinks per week) had lower platelet aggregability—this was true for women as well as men, they note. They also showed that moderate alcohol intake was linked to lower levels of platelet activation in 1000 people. This latter association "was clearly there in men," Mukamal says and it looks like it also holds for women, although there were fewer females assessed for this marker.

"Additional research is needed to clarify whether these relationships may mediate, at least in part, the contrasting associations of alcohol consumption with risk of thrombotic and hemorrhagic cardiovascular events," the researchers write.

Interestingly, Mukamal told heartwire that a new treatment for ischemic stroke combining alcohol and caffeine—known as caffeinol—is being tested in animals. Early results have been published in a number of journals [2,3], he says.