Effects of a train fare subsidy program on the daily walking steps of prime-aged adults: A randomized controlled trial of the Senboku Rapid Railway

This study aimed to examine the effect of a train fare subsidy program on daily walking steps. In addition, this study investigated the steps of the following subgroups: prime-aged adults (20–49 years old), middle-aged adults (50–64 years old), and older adults (≥65 years old). This study's research design was a 7-week randomized controlled trial of 900 participants who used the HealthSmart-Senboku smartphone application. This study subsidized the intervention group with either 2000 or 1000 points, which could be exchanged for digital train tickets worth JPY 2000 or JPY 1000 on the Senboku Rapid Railway. The participants were assigned to the control group or two intervention groups, with 300 participants per group. The primary outcomes were daily walking step data that were automatically recorded by the application. The results revealed that participants of all ages did not significantly change their daily walking steps at the 5 % significance level. Moreover, the intervention group (subsidized by 1000 points) significantly increased daily walking steps by 711.43 [–162.36, 1585.23] steps/day for prime-aged adults (p value = 0.048). Our findings suggest the effectiveness of a program coupled with train fare subsidies to promote active travel, with a focus on prime-aged adults.