||BACKGROUND: Mobile technologies have wide-scale reach and disseminability, but no known studies have examined mobile technologies as a stand-alone tool to improve obesity-related behaviors of at-risk youth.
PURPOSE: To test a 12-week mobile technology intervention for use and estimate effect sizes for a fully powered trial.
METHODS: Fifty-one low-income, racial/ethnic-minority girls aged 9-14 years were randomized to a mobile technology (n=26) or control (n=25) condition. Both conditions lasted 12 weeks and targeted fruits/vegetables (FVs; Weeks 1-4); sugar-sweetened beverages (SSBs; Weeks 5-8), and screen time (Weeks 9-12). The mobile intervention prompted real-time goal setting and self-monitoring and provided tips, feedback, and positive reinforcement related to the target behaviors. Controls received the same content in a written manual but no prompting. Outcomes included device utilization and effect size estimates of FVs, SSBs, screen time, and BMI. Data were collected and analyzed in 2011-2012.
RESULTS: Mobile technology girls used the program on 63% of days and exhibited trends toward increased FVs (+0.88, p=0.08) and decreased SSBs (-0.33, p=0.09). The adjusted difference between groups of 1.0 servings of FVs (p=0.13) and 0.35 servings of SSBs (p=0.25) indicated small to moderate effects of the intervention (Cohen's d=0.44 and -0.34, respectively). No differences were observed for screen time or BMI.
CONCLUSIONS: A stand-alone mobile app may produce small to moderate effects for FVs and SSBs. Given the extensive reach of mobile devices, this pilot study demonstrates the need for larger-scale testing of similar programs to address obesity-related behaviors in high-risk youth.