Objective: To report on long-term effects of a cluster randomized controlled kindergarten-based intervention trial, which aimed to increase vegetable intake among Norwegian preschool children (3-5 years at baseline). The effects of the intervention at follow-up 1 (immediately post-intervention) have previously been published. This paper presents the effects of the intervention from baseline to follow-up 2 (12 months post-intervention).
Results: Parental consents were obtained for 633 out of 1631 eligible children (response rate 38.8%). The effects of the intervention from baseline to follow-up 2 were assessed by mixed-model analyses taking the clustering effect of kindergartens into account. Children's vegetable intake was reported by the parents at baseline (spring 2015), at follow-up 1 (spring 2016) and at follow-up 2 (spring 2017). No significant long-term effects in child vegetable intake were found. A mean difference of - 0.1 times per day (95% CI - 0.5, 0.2) (P = 0.44) was found for the daily frequency of vegetable intake. A mean difference of - 0.2 different kinds of vegetables eaten over a month (95% CI - 1.0, 0.7) (P = 0.70) was found and for daily amount of vegetables a mean difference of - 15.0 g vegetables (95% CI - 38.0, 8.0) (P = 0.19) was found. Trial registration International Standard Randomised Controlled Trials ISRCTN51962956 (http://www.isrctn.com/ISRCTN51962956). Registered 21 June 2016 (retrospectively registered).
Keywords: Kindergarten-based intervention; Long-term intervention effect; Norway; Preschool children; RCT; Vegetables.