JMIR Publications

ABSTRACT

Background:

As the population ages, older adults face an increasing risk of physical inactivity and related health complications, highlighting the need for scalable interventions to promote physical activity. Smartphone-based programs have emerged as a promising strategy to support sustained physical activity among older adults.

Objective:

This study aimed to evaluate whether a smartphone lecture program incorporating digital peer support would increase physical activity among older adults, compared to a conventional smartphone lecture program.

Methods:

This 2-arm, 1:1 parallel-group, cluster-randomized trial was conducted in two urban regions of Japan (Sumida Ward, Tokyo, and Chiba City, Chiba). A total of 156 community-dwelling older adults (aged ≥60 years, able to walk independently, and smartphone users) were grouped into 40 clusters and randomized (20 intervention clusters [n = 80], 20 control clusters [n = 76]). Exclusion criteria included prior use of the peer support app or medical restrictions on walking. In total, 124 participants (79.5%) completed the follow-up, and walking step data were available for 117 participants. All participants received a baseline smartphone lecture. Intervention participants attended two additional sessions using a digital peer support app (MinChalle), which included features such as daily step goals, peer sharing, and group encouragement. Control participants attended two standard follow-up smartphone lectures. The primary outcome was change in weekly average daily step count from baseline. Secondary outcomes included total Metabolic Equivalent of Task (MET)-minutes per week (assessed via the International Physical Activity Questionnaire), walking time (≥30 minutes/day), daily smartphone use, and number of smartphone use purposes.

Results:

Baseline daily steps averaged 3,975 (SD 1,590) in controls versus 4,318 (SD 1,513) in the intervention arm (p=0.24). Adjusted linear mixed models showed significantly higher steps for intervention participants at week 11 (difference=509; 95% CI=70 to 947; p=0.02) and week 12 (difference=479; 95% CI=41 to 918; p=0.03). No significant differences emerged for total METs (difference=714 MET-min/week; 95% CI=–204 to 1,631; p=0.12) or walking ≥30 minutes/day (OR=1.15; 95% CI=0.42 to 3.20; p=0.78). However, the intervention group demonstrated a suggestive increase in daily smartphone use (OR=3.8; 95% CI=0.85 to 17.0; p=0.08) and a significant increase in the number of smartphone use purposes (difference=0.59; 95% CI=0.10 to 1.08; p=0.02).

Conclusions:

A smartphone lecture program integrated with app-based peer support led to modest but meaningful improvements in step counts among older Japanese adults, especially in later weeks of the 12-week intervention. Future research should investigate long-term maintenance, additional measures of physical activity, and subpopulation responses to optimize digital health programs for older adults. Clinical Trial: UMIN000051904