However, a recent study by Li et al. (2011) using the first two waves of the ITC-China project to examine prospective predictors of making a quit attempt and quit success among those who tried, failed to find any independent association between these outcomes and SES indicators such as income EMD 1214063 and education. This suggests that the observed influence of SES on quitting activity may be entirely indirect, something that awaits confirmation. Although Li et al. (2011) showed that Chinese smokers with lower nicotine dependence, higher self-efficacy, and more immediate quitting intentions were more likely to make a quit attempt independent of other factors, the predictive utility of these three factors for quit maintenance among Chinese smokers who had made a quit attempt is less clear and deserves further research.

Using the same data from the ITC-China survey as Li et al. (2011) but adding an additional wave (total of three waves), this study aimed (a) to examine whether nicotine dependence, quitting self-efficacy, and quit interest differed by SES and (b) whether SES influenced the likelihood of making a quit attempt and succeeding in an attempt directly or indirectly via these factors, among Chinese smokers from seven cities. METHODS Sample Data come from the first three waves (Waves 1�C3) of the ITC-China survey, a face-to-face cohort study modeled after the ITC-4 country study designed to evaluate the psychosocial and behavioral impacts of tobacco control policies (Fong et al., 2006; Thompson et al., 2006).

The ITC-China cohort was recruited using a multistage cluster sampling method to obtain a representative sample of adult smokers who were registered residents in the seven cities (Beijing, Shenyang, Shanghai, Changsha, Guangzhou, Yinchuan, and subsequently a new city, Kunming, was added starting in Wave 3). These cities were selected based on geographic representations and levels of economic development. The ITC-China survey was conducted through face-to-face interviews using a standard protocol. Details of the study methodology have been reported elsewhere (Wu et al., 2010). Briefly, in each city, 10 Jie Dao or Street Districts were selected with probability of selection proportional to population size of the Jie Dao. Within each Jie Dao, two Ju Wei Hui or residential blocks were selected, with selection probability proportional to size.

Within each selected Ju Wei Hui, a complete list of addresses of the dwelling units (households) was first compiled, and then a sample of 300 households were drawn from the list by simple random sampling without replacement. The enumerated 300 households were ordered randomly, and adult smokers were then approached until 40 adult smokers were surveyed. Smokers were defined as those Drug_discovery who had smoked more than 100 cigarettes in their life and smoked at least weekly at the time of the survey.