Aims: To describe the long-term natural history of a range of potential determinants of relapse from quitting smoking.
Design, setting and participants: A survey of 2502 ex-smokers of varying lengths of time quit recruited as part of the International Tobacco Control (ITC) Four Country Survey (Australia, Canada, United Kingdom, United States) across five annual waves of surveying.
Measurements: Quitters were interviewed by telephone at varying durations of abstinence, ranging from 1 to 1472 days (about 4 years) post-quitting. Smoking-related beliefs and experiences (i.e. urges to smoke; outcome expectancies of smoking and quitting; and abstinence self-efficacy) were included in the survey.
Findings: Most theorized determinants of relapse changed over time in a manner theoretically associated with reduced risk of relapse, except most notably the belief that smoking controls weight, which strengthened. Change in these determinants changed at different rates: from a rapidly asymptoting log function to a less rapidly asymptoting square-root function.
Conclusions: Variation in patterns of change across time suggests that the relative importance of each factor to maintaining abstinence may similarly vary.