Comparison of plasma levels of natural anticoagulants (protein C and protein S) among Jordanian smokers and non-smokers.

Background: Protein C (PC) with its cofactor free protein S (FPS) are important anticoagulants. Any defect in the PC system is a risk factor for venous thrombosis.

Aims: To assess the effect of intensity of smoking, and the dose-response for the number of cigarettes smoked on PC and FPS plasma levels.