A comprehensive multicomponent school-based educational intervention did not affect fruit and vegetable intake at the 14-year follow-up

Abstract The intake of fruit and vegetables is associated with beneficial health outcomes, and studies aimed at increasing fruit and vegetable intake lack long-term follow-up. The primary objective of this study was to evaluate the long-term (14-year) effects of a multicomponent school-based educational intervention targeted to increase fruit and vegetable intake in children. The secondary objective was to evaluate the potential synergistic effect between free school fruit and the educational program. A cluster randomized school-based intervention was initiated in 2001 in Norway, known as the Fruit and Vegetable Make the Marks study. In total, 38 schools were randomized; for the intervention ( n  = 18) and as control schools ( n  = 20). A subsample of the intervention schools ( n  = 9) were additionally given free school fruit, resulting in two intervention groups - one with and one without free fruit. Participants completed questionnaires in September 2001 (baseline, mean age 11.8), May 2002 (at the end of the intervention), May 2003, May 2005, September 2009 and throughout 2016 (mean age 26.5). Of 1950 participants, 982 (50.4%) completed the 14-year follow-up and were considered as the current study sample. Analysis yielded no 14-year effects of the educational program on fruit and vegetable intake. A synergistic effect between the educational program and free fruit was not observed either. Future studies might benefit from increased focus on more extensive parental involvement, increased home availability, and a longer intervention period. However, more long-term studies are needed to evaluate the effects of school-based interventions into adulthood. Trial registration number: Ethical approval and research clearance was obtained from The National Committees for Research Ethics in Norway (file number S-01076) and The Norwegian Centre for Research Data (file number 12395).