Evaluation of a Population-Wide Mobile Health Physical Activity Program in 696 907 Adults in Singapore

Abstract

Background Evidence of scaled-up physical activity interventions is scarce. This study evaluates the uptake, engagement, and effectiveness of one such intervention program. Methods and Results The program was open to individuals aged ≥17 years in Singapore. The main intervention components comprised device-based daily physical activity recording paired with step count goals and financial rewards. According to the different reward opportunities, we divided the evaluation period (August 2017 to June 2018) into the baseline monitoring phase, the main challenge phase, and the maintenance phase. Uptake was assessed by the number of individuals registered, and engagement by the step recording duration after registration. The effectiveness was defined as changes in mean daily step count from baseline to the main challenge phase and the maintenance phase. A total of 696 907 participants registered, including more Singapore citizens (versus noncitizens), women, and younger (aged 17-39 years) individuals. The evaluation of engagement and effectiveness included 421 388 (60.5%) participants who provided plausible characteristic information and step count data. The median duration of engagement was 74 (IQR, 14-149) days. Compared with the baseline of 7509 (SD, 3467) steps, mean daily step count increased by 1579 (95% CI, 1564-1594) steps during the main challenge phase and 934 (95% CI, 916-952) steps during the maintenance phase. Greater engagement and activity increase were found in participants who are citizens, women, aged ≥40 years, non-obese, and using separate wearables (versus smartphones). Conclusions Mobile health physical activity interventions can successfully reach a large population and be effective in increasing physical activity, despite declining program engagement over time.

Keywords: mobile health; physical activity; primary prevention; public health.

Figure 1. Program implementation time frame and evaluation phases.

A, NSC3 implementation time frame. B, Participant‐specific NSC3 evaluation phases and the eligible rewards according to the participant’s registration time. Participants varied in time windows of the 3 NSC3 phases because of their different program registration time. NSC3 indicates National Steps Challenge Season 3.

Figure 2. Participant flowchart.

NSC3 indicates National Steps Challenge Season 3.

Figure 3. Daily and cumulative NSC3 uptake over time from September 26, 2017, to April 29, 2018 (N=696 907).

NSC3 indicates National Steps Challenge Season 3.

Figure 4. Percentage of daily step recording and the mean daily step counts over time (N=421 388).

A, Percentage of registered participants on each calendar date who engaged in NSC3 as well as who remained in NSC3. Registered participants for a specific calendar date reflected all the participants who registered for NSC3 by that date. A registered participant remained in NSC3 until the last day the participant recorded daily step counts. B, Mean daily step counts on each calendar date, stratified according to the 3 specified NSC3 phases (baseline monitoring phase, main challenge phase, and maintenance phase). Black dots indicate weekend days; red dots indicate nonweekend public holidays. N=421 388 reflects the total number of participants who contributed data to Figure 4, but the mean daily step counts on specific dates were computed on the basis of participants who provided step count data on the date. The number of participants in each NSC3 phase with step count data on each calendar date can be found in Table S9. NSC3 indicates National Steps Challenge Season 3.