Efficacy of Osteoporosis Prevention Smartphone App.

Background: The Striving to be Strong study tested the efficacy of a multifaceted, theory-based, complex osteoporosis prevention smartphone application (app). We hypothesized use of the app would improve bone mineral density and trabecular bone scores.

Methods: The study was a three-group, prospective, repeated-measure, longitudinal randomized trial. Baseline sample consisted of 290 healthy women between 40 and 60 years of age. Participants were randomly assigned to one of three groups: "Striving," a dynamically tailored, person-centered app; "Boning Up," a standardized osteoporosis-education e-book; and "Wait List," a participant's choice of intervention in the final 3 months of the 12-month study. Participants had or were provided a smart phone. Bone mineral density and trabecular bone scores were measured using dual-energy X-ray absorptiometry at baseline and 12 months. To assess engagement in health behavior change processes, ecological momentary assessments were administered via text messaging during the 12 months participants actively used the app.

Results: The final sample reflects an 89.6% retention rate. There were decreases in bone mineral density over time but not among the three groups. The percentage of bone density lost over 12 months was lower than expected. Trabecular bone scores were not different over time or by group but improved across all three groups.

Discussion: Small but positive results were observed across all groups, suggesting one or more aspects of participation might have affected outcomes, including dissemination of the intervention across groups, retention without participation, ecological momentary assessments functioning as both an intervention and measure, and selective engagement in research-based recommendations.