VCAM1 and systemic lupus erythematosus: On review of the literature, however, few studies have found an association with serum VCAM-1 and smoking; in fact, one study found an inverse association in lupus patients.17 In vitro studies have shown some increased expression of VCAM-1 on the surface of endothelial cells following exposure to nicotine.18 The relationship of serum VCAM-1 and smoking status is not yet clear and there may be unmeasured confounding contributing to our result.