all analyses conducted with the VAANX sample. Because the VAANX was selected by the genetic factor score, there were not enough individuals with high and low FTQ or FTND scores for a dichotomized design, so we used a quantitative design (FTND scores) to assess ND in this sample. As defined in the VAND sample, individuals who reported never having smoked regularly and whom we, therefore, did not attempt to assess with the FTQ or FTND were classified as nonsmokers. All others were classified as smokers, including those who were not smoking at assessment but had smoked previously. The remaining 961 individuals included 532 nonsmokers (299 men and 233 women) and 429 smokers (276 men and 153 women). The distributions of FTND scores for these individuals are shown in Figure 1. For the study participants, both the FTQ and FTND scores were negatively correlated with the level of education (polychoric correlation: FTQ, r=−0.31 [P=.04]; FTND, r=−0.33 [P=.04]) and socioeconomic status as measured by yearly income (polychoric correlation: FTQ, r=−0.20 [P=.047]; FTND, r=−0.23 [P=.05]).
