The present study also aimed to investigate potential association between the studied SNPs and smoking status reported using questions about current smoking habits. The participants were asked how many cigarettes they smoke on an average day with a 5‐point response format: not at all; ≤ 10; 11–20; 21–30; > 30 (Table 1). This outcome was significantly correlated to AUDIT scores in the whole sample (partial correlation controlling for gender and age, r = 0.32, n = 4071, P < 0.001). According to the Fagerström Test for Nicotine Dependence (Heatherton et al. 1991), smoking fewer than 11 cigarettes per day does not add to the final score of nicotine dependence. Subjects in this group were thus excluded from all smoking‐related analyses while individuals that reported to smoke more than 10 cigarettes per day (n = 472) were grouped together in order to capture individuals that were more likely to be nicotine‐dependent.
