Effects on secondary outcomes following a three-month personalized app-based lifestyle intervention among working adults: a three-armed randomized controlled trial.

Lifestyle improvements can bring individual and societal benefits. Most interventions are standardized; however, personalized interventions may be more effective. We examined the effect of a personalized app‑based lifestyle intervention, with or without monthly coaching, on physical activity, diet, alcohol, sleep, stress, and smoking, in a three‑month randomized controlled trial. Office workers and bus drivers (n = 209) were randomized 1:1:1 to app, app-coach, or control group. Differences in change from baseline to follow‑up were analysed using robust linear regression, with the control group as the reference. Participants were on average 48.2 years and 42% were female. Both intervention groups increased minutes of exercise (app group β = 15.7 min/week, 95% CI: 3.5, 27.9; app-coach group β = 13.8 min/week, 95% CI: 1.4, 26.1). Compared to the control group, participants in the app-coach group increased their vegetable intake (β = 51.8 g/day, 95% CI: 2.5, 101.1) and fruit and vegetable intake (β = 87.7 g/day 95% CI: 8.9, 166.6). Participants in the app-coach group also increased time in bed (β = 0.43 h/night, 95% CI: 0.05, 0.81) and sleep duration (β = 0.40 h/night, 95% CI: 0.01, 0.78). No other outcomes differed between groups. While the effects seen on physical activity, diet and sleep were limited, even small behavioural changes can benefit health. Though, the effect of coaching needs further evaluation. Future personalized app-based interventions have potential to improve lifestyle behaviours.