The mean serum concentrations of 3-HC and cotinine at baseline are shown in Table 1. Five participants were classified as faster metabolizers and 15 were classified as slower metabolizers. The distribution of serum 3-HC:cotinine ratios in the study sample is shown in Figure 1. Participants reported a mean of 7.1 (SD=4.6) hours since smoking their last cigarette. Baseline cotinine was highly correlated with both exhaled CO and cigarettes smoked per day (r=.80, p<.01 and r=.53, p=.01 respectively). Baseline 3-HC was also highly correlated with exhaled CO and cigarettes smoked per day (r=.63, p=.02 and r=.47, p=.03 respectively). At baseline, there were no significant differences in demographic characteristics, smoking behaviors and serum cotinine between faster and slower metabolizers (see Table 1). There was also a trend for faster metabolizers to have a higher HONC score (p=0.09).
