The Effectiveness of Sequentially Delivered Web-Based Interventions on Promoting Physical Activity and Fruit-Vegetable Consumption Among Chinese College Students: Mixed Methods Study (Preprint)

Abstract

BACKGROUND Evidence indicated a high prevalence of physical inactivity and insufficient consumption of fruit and vegetables among college students. Web-based interventions for multiple health behavior change (MHBC) appears to be a promising approach to change the unhealthy habit. Limited research has tested this assumption in promoting physical activity (PA) and fruit-vegetable consumption (FVC) among Chinese college students. Moreover, the best sequential delivery mode of MHBC intervention needs to be addressed. OBJECTIVE From both quantitative and qualitative perspectives, this study aimed to examine (1) the effectiveness of two sequentially delivered 8-week web-based interventions on PA, FVC and health-related outcomes, and (2) which sequential timing is superior in behavior change. The intervention content was based on the health action process approach. Self-reported data were evaluated including PA, FVC, and health-related outcomes (Body Mass Index (BMI), depression and quality of life). METHODS In a randomized controlled trial (RCT), 552 eligible college students (Mean = 19.99 ± 1.04 years, 58.3% female) were randomly assigned to one of three groups: PA-first (4 weeks of PA followed by 4 weeks of FVC intervention), FVC-first (4 weeks of FVC followed by 4 weeks of PA intervention), and a control group (8 weeks of placebo treatment unrelated to PA and FVC). A total of 4 web-based assessments were conducted, including at baseline (T1, n = 565), after 4 weeks (T2, after the first behavior intervention, n = 486), after 8 weeks (T3, after the second behavior intervention, n = 420), and after 12 weeks (T4, 1-month post-intervention follow-up, n = 348). In addition, after the completion of the entire 8-week intervention, 18 participants (Mean = 19.56 ± 1.04 years, 55.6% female) who completed the whole program were immediately invited to attend one-to-one and face-to-face semi-structured interviews. The participants were asked about their experience of participating in this program regarding their changes in health behaviors and health-related outcomes. The entire study was conducted throughout the fall semester of 2017. RESULTS Both quantitative and qualitative data supported superior effects on PA, FVC and BMI in two sequential intervention groups compared to the control group. In addition, the quantitative data found no significant behavior change differences between two sequential intervention groups after 8 weeks. But FVC-first group contributed to more maintenance of FVC compared to the PA-first group after 12 weeks. Findings from the qualitative study revealed that both intervention groups reported superior effects for the first addressed behavior after 8 weeks. CONCLUSIONS This study provides comprehensive evidence for the effectiveness of sequentially delivered web-based MHBC interventions on PA and FVC among Chinese college students. The efficacy of two sequential timing interventions on behavior change is mixed in quantitative and qualitative data. The delivery mode of MHBC interventions in the future is discussed. CLINICALTRIAL ClinicalTrials.gov NCT03627949(posted on April 18, 2019). INTERNATIONAL REGISTERED REPORT RR2-10.1186/s12889-019-7438-1