Changes in adolescents’ and parents’ intakes of sugar-sweetened beverages, fruit and vegetables after 20 months: results from the HEIA study – a comprehensive, multi-component school-based randomized trial

BACKGROUND: Interventions conducted in school-aged children often involve parents, but few studies have reported effects on parents’ own behaviour as a result of these interventions. OBJECTIVE: To determine if a multi-component, cluster randomized controlled trial targeting 11–13 year olds influenced their consumption of fruit, vegetables, sugar-sweetened soft drinks and fruit drinks, and to explore whether the results varied by gender, adolescent weight status or parental educational level. A final aim was to assess whether the parents’ intakes were affected by the intervention. DESIGN: Participants were 1,418 adolescents, 849 mothers and 680 fathers. Baseline and post-intervention data from the 20 months intervention study HEIA (HEalth In Adolescents) were included. Data were collected assessing frequency (and amounts; beverages only). RESULTS: No significant differences were found at baseline between the intervention and control groups, except for the parental groups (educational level and intakes). At post-intervention, the adolescents in the intervention group consumed fruit more frequently (P<0.001) and had a lower intake of sugar-sweetened fruit drinks compared to the control group (P=0.02). The parental educational level moderated the effect on intake of sugar-sweetened fruit drinks in adolescents. The intake was less frequent in the intervention groups compared to the control groups (P=0.02) for those who had parents with low and medium educational level. Furthermore, the intervention may have affected mothers’ fruit intake and the vegetable intake in higher educated fathers. CONCLUSION: Favourable effects in favour of the intervention group were found for intake of fruit and sugar-sweetened fruit drinks among the adolescents in the HEIA study. Our results indicate that it is possible to reduce adolescents’ intake of sugar-sweetened fruit drinks across parental education, and potentially affect sub-groups of parents.