Do predictors of smoking relapse change as a function of duration of abstinence? Findings from the United States, Canada, United Kingdom and Australia.

Abstract

To estimate predictors of time to smoking relapse and test if prediction varied by quit duration. Longitudinal cohort data from the International Tobacco Control Four-Country survey with annual follow up collected between 2002 and 2015. Canada, United States, United Kingdom and Australia. A total of 9171 eligible adult smokers who had made at least one quit attempt during the study period. Time to relapse was the main outcome. Predictor variables included pre-quit baseline measures of nicotine dependence, smoking and quitting-related motivations, quitting capacity and social influence, and also two post-quit measures, use of stop-smoking medications and quit duration (1-7days, 8-14days, 15-31days, 1-3months, 3-6months, 6-12months, 1-2years and 2+ years), along with socio-demographics. All factors were predictive of relapse within the first 6months of quitting but only wanting to quit, quit intentions and number of friends who smoke were still predictive of relapse in the 6-12-month period of quitting [hazard ratios (HR)=1.20, P< 0.05; 1.13, P< 0.05; and 1.21, P<0.001, respectively]. Number of friends smoking was the only remaining predictor of relapse in the 1-2years quit period (HR=1.19, P=0.001) with none predictive beyond the 2-year quit period. Use of stop-smoking medications during quit attempts was related negatively to relapse during the first 2weeks of quitting (HR=0.71-0.84), but related positively to relapse in the 1-6-month quit period (HR=1.29-1.54). Predictive effects of all factors showed significant interaction with quit duration except for perceiving smoking as an important part of life, prematurely stubbing out a cigarette and wanting to quit. Among adult smokers in the United States, Canada, United Kingdom and Australia, factors associated with smoking relapse differ between the early and later stages of a quit attempt, suggesting that the determinants of relapse change as a function of abstinence duration.