Effect of the multicomponent healthy high school intervention on meal frequency and eating habits among high school students in Denmark: a cluster randomized controlled trial.

BACKGROUND: Previous studies have shown that multicomponent interventions may improve meal frequency and eating habits in children, but evidence among young people is limited. This study evaluated the effect of the Healthy High School (HHS) intervention on daily intake of breakfast, lunch, water, fruit, and vegetables at 9-month follow-up. METHODS: The study included first-year students (≈16 years) attending high school in Denmark. Participating schools were randomized into the HHS intervention (N = 15) or control group (operating as usual) (N = 15). The intervention was designed to promote well-being (primary outcome) by focusing on healthy habits including meals, stress prevention, and strong peer relations. It included a curriculum, structural and organisational initiatives, a workshop, and a smartphone application. Students completed self-administered online questionnaires at the beginning of the school year and nine months later. To account for clustering of data, we used multilevel logistic regression analyses to estimate odds ratios (OR). We applied an intention-to-treat approach with multiple imputations of missing data. RESULTS: At baseline 4577 of 5201 students answered the questionnaire and 4512 at follow-up. In both groups the proportion of students eating breakfast decreased from approximately 50% to 40% from baseline to follow-up, and lunch frequency decreased from approximately 50% to 47%. Daily water intake, intake of fresh fruit and intake of vegetables remained unchanged from baseline to follow-up. There were no significant between group differences on any of the outcomes at first follow-up: breakfast: OR = 0.85 (95% CI: 0.65;1.10), lunch: OR = 0.96 (95% CI: 0.75;1.22), water intake: OR = 1.14 (95% CI: 0.92;1.40), intake of fresh fruit: (OR = 1.07, 95% CI: 0.84;1.37), vegetables: (OR = 1.01, 95% CI: 0.77;1.33). CONCLUSION: No evidence of an effect of the HHS intervention was found for any of the outcomes. Future studies are warranted to explore how health promoting interventions can be integrated in further education to support educational goals. Moreover, how to fit interventions to the lives and wishes of young people, by also including systems outside of the school setting. TRIAL REGISTRATION: ISRCTN, ISRCTN43284296 . Registered 28 April 2017 - retrospectively registered.

Adaptation, Student Participation and Gradual Withdrawal by Researchers as Sustainability Strategies in the High School-Based Young and Active Intervention: School Coordinators' Perspectives.

Ensuring the sustainability of school-based public health intervention activities remains a challenge. The Young and Active (Y&A) intervention used peer-led workshops to promote movement and strengthen students' sense of community in 16 Danish high schools. Peer mentors inspired first-year students to implement movement activities. To support sustainability, we applied a three-year stepwise implementation strategy using university students as peer mentors in year 1 and senior high school students in the following two years. This study explores the sustainability potential of Y&A, focusing on school coordinators' reflections on the intervention's fit to their schools and the student-driven approach, and we assess the three-step implementation strategy. The study is based on telephone interviews with coordinators (n = 7) from schools that participated in all three years and participant observations of four workshops (a total of approximately 250 participating students). Results were generated through an abductive analysis. Seven schools continued the intervention throughout the three years and adapted it to fit their priorities. The student-driven approach was perceived to be valuable, but few student-driven activities were initiated. Teacher support seemed crucial to support students in starting up activities and acting as peer mentors in workshops. The three-step implementation strategy proved valuable due to the peer-approach and the possibility of gradual adaptation. In future similar initiatives, it is important to address how the adequate staff support of students can be facilitated.

Assessing Health Consequences of Vitamin D Fortification Utilizing a Societal Experiment Design: Methodological Lessons Learned from the D-Tect Project.

By utilizing historical changes in Danish legislation related to mandatory vitamin D fortification of margarine, which was implemented in the mid 1930s and abruptly abandoned in June 1985, the studies in the D-tect project investigated the effects of vitamin D on health outcomes in individuals, who during gestation were exposed or unexposed to extra vitamin D from fortified margarine. This paper reviews and narratively summarizes the analytic approaches alongside the results of the societal fortification experiment studies from the D-tect project and addresses the challenges in designing societal experiment studies and evaluating their results. The latter are discussed as lessons learned that may be useful for designers of similar studies, expected to be extensively utilized while researching the health consequences of the COVID-19 pandemic by comparing individuals born before and after the epidemic. In the D-tect project, 16 articles based on the societal fortification experiment were published analyzing 10 different outcomes and using different statistical approaches. Lessons learned included the detail of the analysis of the historical information on the exposure, availability and validity of the outcome data, variety of analytical approaches, and specifics concerning vitamin D effect evaluation, such as consideration of the influence of sunshine or season. In conclusion, the D-tect project clearly demonstrated the cost-effectiveness and research potential of natural- or societal-experiment-based studies.