Who opts out of a project for health promotion with incentives?: Empirical research on the effect of rewards to motivate persistence.

Objectives　Although providing incentives for a better lifestyle has been of increasing concern, there is insufficient evidence about its effect. Therefore, this research aims to discover new insights by verifying the effect of rewards to motivate persistence in a project for health promotion.Methods　A total of 7,622 participants of an incentivized project for health promotion (Wellness Point Project) were recruited from 6 municipalities in Japan, namely Tohoku, Chubu, Kanto, Kinki, and Chugoku, of which the 4,291 individuals who had the necessary information for estimation were analyzed. Persistence in the project was judged by whether there was information about daily steps and/or participation in some fitness classes every month for one year at most. In addition, we used the reason participants chose certain rewards in order to categorize the characteristic of rewards, and estimated opt-out hazard ratios from the project using survival time analysis. Furthermore, the estimation in the model included individual features such as age, education, status of physical activity before joining the project, lifestyles such as smoking, drinking, and so on.Results　A multivariate analysis reveals that those who had chosen a reward for regional contribution were more likely to opt out than those who had chosen a certain reward because it is close to cash. The opt-out hazard ratio was 1.63 (95% CI: 1.18-2.25) among men and 1.40 (95% CI: 1.08-1.81) among women. In addition, insufficient physical activity, smoking, working for men, and physical condition for women were associated with opt-out.Conclusions　This research verified that a reward that participants felt was close to cash, compared to the internal motivation of regional contribution, could enhance the persistence rate of the project. Moreover, it was found that not only giving incentives but also considering participants' conditions is necessary to enhance persistence.