Individual-level predictors of cessation behaviours among participants in the International Tobacco Control (ITC) Four Country Survey.

BACKGROUND The International Tobacco Control (ITC) Four Country Survey (ITC-4) is a prospective cohort study designed to evaluate the psychosocial and behavioural impact of national-level tobacco control policies enacted in the Australia, Canada, the UK, and the USA. Wave 1 of ITC-4 survey was conducted between October 2002 and December 2002. Wave 2 survey was conducted between May 2003 and August 2003. OBJECTIVE To test for individual-level predictors of smoking cessation behaviours (that is, quit attempts and smoking cessation) among cigarette smokers in the ITC Four Country Study measured between Wave 1 and Wave 2. This set of predictors will serve as the base for evaluating the added effect of tobacco control policies and other factors. METHODS Respondents included in this study are 6682 adult current smokers in the Wave 1 main survey who completed the Wave 2 follow-up (1665 were in Canada, 1329 were in the USA, 1837 were in the UK and 1851 were in Australia). RESULTS Factors predictive of making a quit attempt included intention to quit, making a quit attempt in the previous year, longer duration of past quit attempts, less nicotine dependence, more negative attitudes about smoking, and younger age. Lower levels of nicotine dependence were the main factor that predicted future cessation among those that made a quit attempt. CONCLUSION Intention to quit and other cognitive variables were associated with quit attempts, but not cessation. Behavioural variables related to task difficulty, including measures of dependence, predicted both making attempts and their success. Predictors of making quit attempts and cessation were similar for each of the four countries, but there were some differences in predictors of success.