A cohort study to examine whether time and risk preference is related to smoking cessation success


Takanori Ida, Graduate School of Economics, Kyoto University, Yoshida, Sakyo, Kyoto 606-8501, Japan.
E-mail: ida@econ.kyoto-u.ac.jp


Aim  To identify whether time and risk preference predicts relapse among smokers trying to quit.

Design  A cohort study of smokers who had recently started to quit. Time and risk preference parameters were estimated using a discrete choice experiment (DCE).

Participants  A total of 689 smokers who began quitting smoking within the previous month.

Measurements  Time discount rate, coefficient of risk-aversion measured at study entry and duration of smoking cessation measured for 6 months.

Findings  In the unadjusted model, Cox's proportional hazard regression showed that those with a high time discount rate were more likely to relapse [hazard ratio: 1.18, 95% confidence interval (CI): 1.11–1.25]. A high coefficient of risk-aversion reduced the hazard of relapse (0.96, 0.96–0.97). When adjusted for other predictors of relapse (age, gender, self-efficacy of quitting, health status, mood variation, past quitting experience, the use of nicotine replacement therapy, nicotine dependence), the hazard ratios of time discount rate and the coefficient of risk-aversion is 1.17 (95% CI: 1.10–1.24) and 0.98 (95% CI: 0.97–0.99), respectively.

Conclusions  Those who emphasize future rewards (time–patient preference) and those who give more importance to rewards that are certain (higher risk-aversion) were significantly more likely to continue to abstain from smoking.