Alcohol intake and risk of venous thromboembolism

Venous thromboembolism (VTE) i.e. deep-vein thrombosis (DVT) and pulmonary embolism (PE) is a multicausal disease that shares several risk factors with arterial thrombosis such as age, obesity, and smoking (1-6). It is well established that low to moderate alcohol intake is associated with a lower risk of arterial thrombosis (7), but data on its association with VTE are limited and the results inconsistent. Alcohol intake has an anti-thrombotic effect through modification of platelet function (decreasing aggregating) and through regulation of coagulation and fibrinolysis by increasing the level of tissue plasminogen activator and decreasing the level of fibrinogen (7, 8). Alcohol intake may thus lower the risk of idiopathic VTE (i.e. unprovoked). However, heavy drinking may also provoke VTE for example mediated through cancer (9). Four earlier studies have reported that moderate alcohol consumption was associated with a lower risk of VTE. However, the amount of alcohol for which the lowest risk was reported varied considerably in the studies (10-13). In contrast, other studies found no association between VTE and alcohol intake (14, 15). The Tromsø study showed that intake of liquor was associated with a higher risk of VTE whereas wine intake was associated with a lower risk of VTE (16). However, the Iowa Women ́s health study showed that beer drinking was associated with a lower risk of VTE whereas win and liquor were associated with a higher risk of VTE (11). Lately Wattanakit et al. examined the association between alcohol intake and subtypes of VTE; i.e. idiopathic and provoked VTE. They found no statistically significant association between alcohol intake and VTE (5). However, the hazard ratio (HR) for idiopathic VTE was 0.64 (95% confidence interval [CI]: 0.40-1.01) for moderate alcohol intake compared to non-drinkers. Drinking pattern was only assessed in one study which reported a higher risk of VTE according to binge drinking (16). Thus the data on the association between alcohol intake and VTE is conflicting. Alcohol intake and risk of venous thromboembolism