Physical activity maintenance among young adult cancer survivors in an mHealth intervention: Twelve-month outcomes from the IMPACT randomized controlled trial

Background: Most physical activity (PA) interventions in young adult cancer survivors (YACS) have focused on short-term outcomes without evaluating longer-term outcomes and PA maintenance. This study examined the effects of an mHealth PA intervention at 12 months, after 6 months of tapered contacts, relative to a self-help group among 280 YACS.

Methods: YACS participated in a 12-month randomized trial that compared self-help and intervention groups. All participants received an activity tracker, smart scale, individual videochat session, and access to a condition-specific Facebook group. Intervention participants also received lessons, tailored feedback, adaptive goal setting, text messages, and Facebook prompts for 6 months, followed by tapered contacts. Accelerometer-measured and self-reported PA (total [primary outcome], moderate-to-vigorous [MVPA], light, steps, sedentary behaviors) were collected at baseline, 6, and 12 months. Generalized estimating equation analyses evaluated group effects on outcomes from baseline to 12 months.

Results: From baseline to 12 months, there were no between- or within-group differences in accelerometer-measured total PA min/week, while increases in self-reported total PA were greater in the intervention versus self-help group (mean difference = +55.8 min/week [95% CI, 6.0-105.6], p = 0.028). Over 12 months, both groups increased accelerometer-measured MVPA (intervention: +22.5 min/week [95% CI, 8.8-36.2] vs. self-help: +13.9 min/week [95% CI, 3.0-24.9]; p = 0.34), with no between-group differences. Both groups maintained accelerometer-measured and self-reported PA (total, MVPA) from 6 to 12 months. At 12 months, more intervention participants reported meeting national PA guidelines than self-help participants (47.9% vs. 33.1%, RR = 1.45, p = 0.02).

Conclusion: The intervention was not more effective than the self-help group at increasing accelerometer-measured total PA over 12 months. Both groups maintained PA from 6 to 12 months. Digital approaches have potential for promoting sustained PA participation in YACS, but additional research is needed to identify what strategies work for whom, and under what conditions.