In the present study, polygenic risk scores for smoking were identified based on the large meta-analyses of the Tobacco and Genetics (TAG) Consortium including 20,000–70,000 subjects. Four phenotypes were included in the TAG GWA meta-analyses: ever versus never regular smoking (Ever), age at onset of smoking (AOS), cigarettes per day (CPD) and smoking cessation (Former). The risk alleles from TAG were used to calculate a polygenic risk scores in an unrelated sample of the Netherlands Twin Register (N=1583) and the association between this risk score for smoking and alcohol/cannabis use was explored.
