JMIR Publications

ABSTRACT

Background:

Large scale initiatives to improve diet quality through increased vegetable consumption have had small to moderate success. Digital technologies have features which are appealing for health-related behavior change interventions, and may overcome some of the limitations associated with traditional delivery approaches.

Objective:

This study describes the implementation and evaluation of a smartphone app, called VegEze, that aimed to increase vegetable intake among Australian adults.

Methods:

To better capture the impact of this app in a real world setting the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework was utilized. An uncontrolled, quantitative cohort study was conducted with evaluation conducted after 21 and 90 days of the program. The app was placed in the Apple® App Store® and accompanied by television, radio and social media promotion. Evaluation surveys were embedded into the app using ResearchKit®. The primary outcomes were vegetable intake (serves per day) and vegetable variety (types per day). Psychological variables (attitudes, intentions, self-efficacy and action planning) and app usage were also assessed. Descriptive statistics and multiple linear regression were used to describe the impact of the app on vegetable intake, and determine the user characteristics associated with increased intake.

Results:

Data were available from 5062 participants who completed the baseline survey, 1224 who completed the 21 day survey and 273 who completed the 90 day survey. The sample resided all around Australia, were mostly female (84.3%) with a mean age of 48.2 years (SD=14.1). The mean increase in intake was 0.48 serves, from 3.06 serves at baseline to 3.54 serves at the end of the 21 day challenge (t(1223)=8.71, P<.001). Variety of vegetables also increased by 0.35 types per day (t(1123)=9.59, P<.001). Participants with the highest app usage increased their vegetable intake by 0.63 (SD=2.02) serves per day compared to 0.32 (SD=1.69) for those with the lowest app usage. Based on multiple linear regression gender, age, BMI; psychological variables of self-efficacy, attitudes, intentions and action planning specific to vegetables; baseline vegetable intake and active days of app usage accounted for 23.3% of the variance associated with change in intake (F(9,1208)=42.09, P<.001). Baseline vegetable intake was the strongest predictor of change in intake (β=-0.495, P<.001), with lower baseline intake associated with greater change in intake. Self-efficacy (β=0.116, P<.001), action planning (β=0.066, P=.017), BMI (β=0.070, P=.009) and app usage (β=0.081, P=.002) were all significant predictors of change in intake.

Conclusions:

The VegEze app was able to shift intake by half a serve in a large sample of Australian adults. Testing the app in a real world setting and embedded the consent process allowed for greater reach, and efficient and robust evaluation. App usage was associated with successful behavior change, but further work to improve engagement is warranted. Clinical Trial: CSIRO Health and Medical Human Research Ethics Committee (CHM HREC) Low Risk Review Panel (Proposal #13/2017). Australian New Zealand Clinical Trials Registry (ACTRN12618000481279).