Abstract
OBJECTIVE: The aim of this study was to investigate the effect of a financial incentive on the number of daily walking steps among community-dwelling adults in Japan. STUDY DESIGN: Two-arm, parallel-group randomised controlled trial. SETTING/PARTICIPANTS: We recruited physically inactive community-dwelling adults from Sendai city, Japan. Eligible participants were randomly allocated to an intervention or a wait list control group. Pedometers were used to assess the mean number of daily steps in three periods: baseline (weeks 1-3), intervention (weeks 4-6) and follow-up (weeks 7-9). INTERVENTION: The intervention group was offered a financial incentive (shopping points) to meet the target number of increased daily steps in the intervention period. MAIN OUTCOME MEASURES: The primary outcome was an increase in the mean number of daily steps in the intervention and follow-up periods compared with baseline. RESULTS: Seventy-two participants (69.4% women; mean age, 61.2±16.2 years; mean number of daily steps at baseline, 6364±2804) were randomised to the intervention (n=36) and control groups (n=36). During the intervention period, the increase in mean daily steps was significantly higher in the intervention group (1650, 95% CI=1182 to 2119) than in the control group (514, 95% CI=136 to 891; p<0.001). However, the difference between groups was not significant at follow-up after the incentives were removed (p=0.311). In addition, compared with controls, a significantly higher proportion of participants in the intervention group showed an increase in mean daily steps of ≥1000 (69.4% vs 30.6%, respectively; OR=5.17, 95% CI=1.89 to 14.08). There were no adverse effects from the intervention. CONCLUSIONS: The present results suggest that financial incentives are effective in promoting short-term increases in physical activity. TRIAL REGISTRATION NUMBER: UMIN000033276.