Results of the discrete time survival latent class growth analysis indicated that, compared to low users and early quitters, middle and late quitters were less likely to survive to an advanced age. There were no significant differences in hazard rates between low users and early quitters and between middle and late quitters. Estimated survival curves (Figure 2) suggested that low users had a higher probability of survival by age 81–85, whereas late quitters had the lowest survival probability by age 81–85. Survival curves were similar for early and middle quitters, but by age 65–69, middle quitters had a significantly lower survival probability. Though lifetime users had an unexpectedly high survival probability in comparison to other groups, the fact that this class contained only 11 participants increases the likelihood that this result is not representative of this group of smokers.
