I thank Dr Jay for his comments on the role of tobacco smoking as a potential risk factor for VTE. While no one would disagree that tobacco smoking is an established risk factor for arterial events such as stroke, myocardial infarction, and peripheral vascular disease, its role as an independent risk factor or effect modifier for VTE remains, to date, unsubstantiated, which is why it was not included as a risk factor in my recent review article.1 The study by Goldhaber et al2 referenced by Jay, based on Framingham Study data, in fact demonstrated that cigarette use was not independently associated with pulmonary embolism at autopsy. In a recent large prospective study on VTE risk based on data from the Physicians' Health Study, patients who developed VTE during follow-up were significantly less likely to have been smokers at baseline than patients who remained free of VTE.3 Other studies on prediction of VTE in various patient populations have shown that cigarette smoking had either no effect4 or a "protective" effect5,6 on risk for VTE. The mechanism underlying a protective effect, if indeed it is real, might be that smoking is a marker for a true protective factor such as lower body weight or better general health status (ie, "healthy smoker" effect, whereby as long as one remains healthy one continues to smoke).
Kahn SR. Cigarette Smoking: Risk Factor for Venous Thromboembolic Disease?. Arch Intern Med. 1999;159(10):1144. doi: