Time and risk preference parameters and the success of smoking cessation

Abstract

Objective: To identify whether the time and risk parameters and the factors analysed in previous research predict the success of smoking cessation. Design: A longitudinal survey for smokers who recently started to quit. Time and preference parameters are individually estimated using a discrete choice experiment (DCE). Setting: Japan, 2007. Participants: A total of 689 smokers who began quitting smoking within the last month. Main outcome measures: Time discount rate, the coefficient of risk aversion, and duration of smoking cessation. Results: Within a proportional hazards regression model, the high time discount rate is associated with failure to quit (hazard ratio: 1.17, 95% confidence interval: 1.10 to 1.24, P < 0.001). The high coefficient of risk aversion improves the overall success of smoking cessation (0.20, 0.07 to 0.53, P = 0.001). Among the conventional variables analysed in previous research, the high self-efficacy of quitting (0.87, 0.79 to 0.95, P = 0.003), the use of nicotine replacement therapy (0.68, 0.49 to 0.96, P = 0.029) and high nicotine dependence are associated with successful cessation. Inexperienced quitters are significantly more likely to fail to quit (3.35, 1.61 to 7.00, P = 0.001). Age, gender, health status and mood variations have no significant effect. Conclusions: Our study indicated that those who emphasize future rewards (time-patient preference) and those who give more importance to rewards that are certain (more risk-averted preference) were significantly more likely to continue to abstain from smoking. Time and risk preference parameters were good predictors of cessation.