The results of this study should be interpreted in the context of several limitations. First, the power was limited in specific treatment or placebo arms due to sample sizes. Thus, the observed association or lack of association between CHRNA5 and smoking cessation should be considered preliminary. Second, the genetic risk for cessation cannot be directly compared across the different pharmacotherapy conditions (cNRT vs. varenicline) due to dissimilar study designs. Third, this work studies only one gene and it is clear that multiple genes contribute to smoking cessation success. Finally, this study only included subjects of European descent.
