A theory-based randomized controlled trial in promoting fruit and vegetable intake among schoolchildren: PROFRUVE study

Abstract

Purpose The main objective of the PROFRUVE study was to evaluate the effectiveness of a TPB-based intervention program at increasing fruit and vegetable (FV) consumption in schoolchildren aged 7–10. Methods Eight eligible classrooms were randomly assigned to the intervention (classrooms n = 4; children n = 90) or control group (classrooms n = 4; children n = 95). The intervention group received 14 sessions of 1 h during an academic year (from October to June) but the control group did not. Sessions were based on the Theory of Planned Behavior (TPB) and focused on modifying FV intake. FV consumption was evaluated before, shortly after and 1 year after intervention ended using validated 7-day food records. Results FV intake increased significantly in the intervention group (+ 0.45 servings/day; 95% CI 0.17–0.74; p = 0.001) but not in the control group (+ 0.01 servings/day; 95% CI −0.20–0.22; p = 0.409) shortly after the intervention. Long-term measurement showed that 1 year after intervention finished, the intervention group maintained the effect (+ 0.52 servings/day from baseline; 95% CI 0.22–0.78; p = 0.003). Linear mixed model also showed that nested groups by classrooms differ from intervention and control groups regarding FV intake change (p = 0.002). Multiple linear regression showed that receiving the intervention (B = 0.345, p = 0.045) and FV baseline intake (B = − 0.383, p = 0.000) were associated with FV intake change after adjusting the model by age, gender and family social economic status (SES) (R2 = 0.196). Conclusions The intervention program based on TPB seemed to be moderately effective in increasing FV intake and successful in maintaining the effect of the reached increase. Moreover, baseline FV intake determined the effect size of the intervention. Trial Registration This study was registered at ClinicalTrials.gov. Identifier: NCT03400891. Data registered 17/01/2018.