For each subject, information about pregnancy, active malignancy, recent (<3 mo) surgery or trauma, fracture, immobilization, acute medical illness, use of oral contraceptives, long-distance travel, personal or family history of arterial and/or venous thrombosis or repeated birth losses will be collected. In the presence of at least one of the previous risk factors, VTE will be defined as secondary otherwise idiopathic. Further information, collected from the whole population by a trained staff, were the following: gender, age, weight, height, body mass index (BMI), waist circumference, personal history of symptomatic atherosclerosis (i.e. ischemic stroke, transient ischemic attack, acute myocardial infarction, angina, intermittent claudication), arterial hypertension, use of antihypertensive drugs, diabetes mellitus, use of antidiabetic drugs, hyperlipidemia, use of statins, smoking habit (use of cigarettes/d), current use of heparin, use of oral anticoagulant (how long) or of antiplatelet drugs (how long), chronic consumption of other drugs.