Fig. 2.

FTND (Fagerström Test for Nicotine Dependence), var(k) and period of abstinence. This plot displays the measured var(k) at T1 of all smokers against the duration of abstinence. Overall, it shows that subjects with higher var(k) tend to relapse earlier than subjects with lower var(k). FTND assessment of nicotine dependence predicted time to relapse. Especially low and very low nicotine dependence levels are associated with better treatment outcomes. Both factors contributed independently to Cox survival prediction. Smokers with high var(k) show earlier relapse regardless of their FTND scores. In this figure, var(k) followed natural log-transformation