A natural experiment: Assessment of Danish high-school students' alcohol drinking patterns from 2014 and 2019 after the introduction of a common alcohol policy.

AIM: In this study, using national survey data from 2014 and 2019, we tested the hypothesis that students at schools who introduced a common alcohol policy in 2017 drank less than students at schools without a common policy. METHODS: We used survey data from 41 high schools that participated in the Danish National Youth Study in 2014 and 2019. We perceived the introduction of a common high-school alcohol policy in 2017 among local groups of high schools as a natural experiment and assessed it using difference-in-difference analyses. We assessed drinking patterns from 2014 and 2019 among students at schools with and without a common alcohol policy combined and stratified by sex in negative binominal regression and logistic regression models. Drinking patterns were measured as average weekly alcohol use, average alcohol intake at last school party, proportion of non-drinkers and frequent binge drinkers. RESULTS: Drinking patterns were similar among students in schools with and without a common alcohol policy. For example, among students at schools with a common alcohol policy, the average alcohol intake at the last school party among drinkers was 8.7 units in 2014 and 8.5 units in 2019, whereas average alcohol intake among students at schools without a common alcohol policy was 8.8 units in 2014 and 8.9 units in 2019 (p=0.413). CONCLUSIONS: No statistically significant effects were observed following the introduction of a common alcohol policy on students' drinking patterns, and alcohol consumption among high-school students was stable and remained high in 2014 and in 2019.

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.

Peer mentors' role in school-based health promotion: qualitative findings from the Young & Active study.

Peer-led interventions are highlighted as promising strategies to promote health among adolescents, but little is known about the mechanisms underlying this approach. To better understand the role of peer mentors (PMs) as implementers in school-based health promotion, we combined participant observations, focus group interviews and video recordings to explore high school students' reception of a peer-led intervention component (Young & Active). Young & Active aimed to increase well-being among first-year high school students (∼16 years of age) through the promotion of movement and sense of community and was implemented during the school year 2016-2017 in a larger school-based intervention study, the Healthy High School study in Denmark. The Healthy High School study was designed as a cluster-randomized controlled trial with 15 intervention schools and 15 control schools. At each intervention school, university students in Sports Science and Health (members of the research group) facilitated an innovation workshop aiming at inspiring all first-year students to initiate movement activities at schools. The findings illustrate potentials and challenges implied in the PM role. The peer mentors' profound commitment, as well as their response and sensibility to situational contingencies, were found to be significant for the students' reception and experience of the intervention. In conclusion, the specific job of PMs as implementers seems to consist of simultaneously following a manual and situationally adjusting in an emerging context balancing commitment and identification to the target group and the intervention project.

Peer-delivery of health promotion is highlighted as a promising strategy to reach adolescents, but little is known about the mechanisms underlying this approach. To better understand the role of peer mentors (PMs) as implementers, we used qualitative methods to explore high school students' reception of a peer-led workshop (Young & Active) in a school-based intervention in Denmark. Young & Active aimed to increase well-being among first-year high school students (∼16 years of age) through the promotion of movement and sense of community and was implemented during the school year 2016­2017. At each intervention school, university students in Sports Science and Health facilitated an innovation workshop to inspire all first-year students to initiate movement activities at schools. We found different potentials and challenges implied in the PM approach. Balancing peer mentors' commitment and identification to the recipients and the intervention seems central.

School Coordinators' Perceptions of Organizational Readiness Is Associated with Implementation Fidelity in a Smoking Prevention Program: Findings from the X:IT II Study.

School organizational readiness to implement interventions may play an important role for the actual obtained implementation level, and knowledge about organizational readiness prior to intervention start can help pinpoint how to optimize support to the schools. In this study, we applied a novel heuristic, R = MC2 to assess school organizational readiness prior to implementation of a multicomponent smoking prevention program. Furthermore, we examined the association to actual implementation after the first year of study. We used questionnaire data from school coordinators at 40 schools in Denmark who had accepted to implement the multi-component smoking prevention intervention-X:IT II-in the school year 2017-2018 including three main components: (1) Rules on smoke-free school time, (2) A smoke-free curriculum, and (3) Parental involvement. On behalf of the school, a school coordinator answered a baseline questionnaire about the organizational readiness and a follow-up questionnaire about implementation of the three components after first year of study. Readiness was measured by summing aspects of motivation (relative advantage, compatibility, complexity, and priority), general capacity (culture, climate, and staff capacity), and innovation-specific capacity (knowledge, skills, and abilities). Based on school coordinators' perceptions, almost all schools had good general capacity while the other two areas of readiness varied across schools; overall, 56.8% of schools (N = 25) had good motivation for implementing the X:IT II intervention and 61.3% (N = 27) had high innovation-specific capacity. Half of the schools had high overall readiness defined as high motivation and high innovation-specific capacity. Schools with high overall readiness implemented the rules on smoke-free school time, smoke-free curriculum, and parental involvement to a higher degree than schools with low overall readiness. All participating schools possessed sufficient levels of general capacity, e.g., a well-functioning organizational culture and sufficient staff capacity. High levels of motivation and innovation-specific capacity were positively associated with the schools' actual implementation of the main intervention components. This way of conceptualizing and measuring organizational readiness may be useful in future studies, i.e., in studies where enhancing readiness is a main objective.

Study protocol of the Healthy High School study: a school-based intervention to improve well-being among high school students in Denmark.

BACKGROUND: The prevalence of low well-being, perceived stress and unhealthy behaviours is high among high school students, but few interventions have addressed these problems. The aim of this paper is to present a study protocol of a cluster randomised controlled trial evaluating the Healthy High School (HHS) intervention programme. The intervention programme is designed to improve well-being (primary outcome) by preventing 1) stress and promoting 2) sleep, 3) sense of community, 4) physical activity (PA) and 5) regular and healthy meals among high school students in Denmark. METHODS: The development of the HHS study was guided by the Intervention Mapping protocol. The intervention comprises four components: 1) a teaching material, 2) a smartphone app, 3) a catalogue focusing on environmental changes, and 4) a peer-led innovation workshop aiming at inspiring students to initiate and participate in various movement activities. The HHS study employs a cluster-randomised controlled trial design. Thirty-one high schools across Denmark were randomly allocated to intervention (16 schools) or control (15 schools) groups. The study included all first-year students (~ 16 years of age) (n = 5976 students). Timeline: Intervention: August 2016 - June 2017. Collection of questionnaire data: Baseline (August 2016), 1st follow-up (May 2017) and 2nd follow-up (April 2018). All students were invited to participate in a monthly sub-study about perceived stress using text messages for data collection (September 2016 - June 2017). PA was objectively assessed among a sub-sample of students using accelerometers (Axivity, AX3) in August 2016 and May 2017. PRIMARY OUTCOME MEASURES: Student well-being measured by the Cantril Ladder and the five item World Health Organisation Well-being Index (individual level outcomes). SECONDARY OUTCOME MEASURES: Stress (10-item Perceived Stress Scale), sleep (quantity and quality), PA (hours of moderate-to-vigorous PA per week, hours of daily sedentary time and average daily PA), meal habits (daily intake of breakfast, lunch, snacks and water), and strong sense of community in class and at school, respectively (individual level outcomes). The study encompasses process and effect evaluation as well as health economic analyses. TRIAL REGISTRATION: ISRCTN ISRCTN43284296, 28 April 2017, retrospectively registered.

Implementation of initiatives to prevent student stress: process evaluation findings from the Healthy High School study.

Process evaluation of public health interventions is important for understanding intervention results and can help explain why interventions succeed or fail. This study evaluated implementation of a school-based intervention combining educational and environmental strategies to prevent stress among Danish high school students. We investigated dose delivered, dose received, fidelity, appreciation, barriers and facilitators at the 15 intervention schools using mixed methods and multiple data sources: questionnaires among students, teachers and school coordinators; semi-structured interviews with school coordinators; telephone interviews with student counsellors; and focus group interviews with students and teachers. Implementation varied by schools and classes. Half of the intervention schools delivered the environmental strategies. For the educational strategies, dose delivered differed according to intervention provider. Students reported a lower dose received compared with dose delivered reported by school staff. Overall, student counsellors, school coordinators and students-especially those with low perceived stress-were satisfied with the stress preventive initiatives while teacher satisfaction varied. Five main barriers and three facilitators for implementation were identified. The use of multiple data sources and data methods created new knowledge of the implementation process which is important for the interpretation of effect evaluation and development of future interventions.

Intake of sugar sweetened soft drinks among adolescents: Trends and social inequality in Denmark 2002-2018.

BACKGROUND: Intake of sugar sweetened soft drinks (SSSD) has decreased among adolescents, but trends in social inequality in SSSD intake are unknown. AIM: Examine trends in social inequality in SSSD intake among adolescents in Denmark during 2002-2018. METHODS: Five Health Behaviour in School-aged Children surveys with data on SSSD intake and parents' occupational social class (OSC) from nationally representative samples of 11, 13 and 15 year olds, n =20,112. RESULTS: The overall prevalence of daily SSSD intake decreased from 10.1% in 2002 to 6.4% in 2018. The prevalence decreased in both high OSC (from 8% to 5%) and middle OSC (from 10% to 6%) but remained around 12% in low OSC. The odds ratio (OR) estimates of low compared with high OSC increased over the years around an overall OR of 2.01 (1.74-2.34). CONCLUSIONS: Danish adolescents' SSSD intake decreased during 2002-2018 and was higher the lower the parents' OSC. Thus, social inequality increased during 2002-2018.

Persistent social inequality in low intake of vegetables among adolescents, 2002-2014.

OBJECTIVE: To examine the trend in social inequality in low intake of vegetables among adolescents in Denmark from 2002 to 2014 using occupational social class (OSC) as socio-economic indicator. DESIGN: Repeated cross-sectional school surveys including four waves of data collection in 2002-2014. The analyses focused on absolute social inequality (difference between high and low OSC in low vegetable intake) as well as relative social inequality (OR for low vegetable intake by OSC). SETTING: The nationally representative Health Behaviour in School-aged Children (HBSC) study in Denmark. SUBJECTS: The study population was 11-15-year olds (n 17 243). RESULTS: Low intake of vegetables was defined as less than weekly intake measured by food frequency items. OSC was measured by student reports of parents' occupation. The proportion of participants who reported eating vegetables less than once weekly was 8·9 %, with a notable decrease from 11·9 % in 2002 to 5·9 % in 2014. The OR (95 % CI) for less than weekly vegetable intake was 2·28 (1·98, 2·63) in the middle compared with high OSC and 3·12 (2·67, 3·66) in the low compared with high OSC. The absolute social inequality in low vegetable intake decreased from 2002 to 2014 but the relative social inequality remained unchanged. CONCLUSIONS: The study underscores that it is important to address socio-economic factors in future efforts to promote vegetable intake among adolescents. The statistical analyses of social inequality in vegetable intake demonstrate that it is important to address both absolute and relative social inequality as these two phenomena may develop differently.

Parental involvement and association with adolescents' fruit and vegetable intake at follow-up: Process evaluation results from the multi-component school-based Boost intervention.

BACKGROUND: Based on the assumption of parental influence on adolescent behavior, multicomponent school-based dietary interventions often include a parental component. The effect of this intervention component is seldom reported and the evidence is inconsistent. We conducted a systematic process evaluation of the parental component and examined whether the leveal of parental involvement in a large multi-component intervention: the Boost study was associated with adolescents' fruit and vegetable (FV) intake at follow-up. METHODS: The Boost study was targeting FV intake among 1,175 Danish 7th graders (≈13- year-olds) in the school year 2010/11. The study included a school component: free FV in class and curricular activities; a local community component: fact sheets for sports- and youth clubs; and a parental component: presentation of Boost at a parent-school meeting, 6 newsletters to parents, 3 guided student-parent curricular activities, and a student-parent Boost event. STUDY POPULATION: Students whose parent replied to the follow-up survey (n = 347). DATA: Questionnaire data from students, parents and teachers at 20 intervention schools. Process evaluation measures: dose delivered, dose received, appreciation and level of parental involvement. Parental involvement was trichotomized into: low/no (0-2 points), medium (3 points) and high (4-6 points). The association between level of parental involvement and self-reported FV intake (24-h recall), was analyzed using multilevel regression analyses. RESULTS: The Boost study was presented at a parent-school meeting at all intervention schools. The dose delivered was low to moderate for the three other parental elements. Most parents appreciated the intervention and talked with their child about Boost (83.5 %). High, medium and low parental involvement was found among 30.5 %, 29.6 % and 39.4 % of the students respectively. Parental involvement was highest among women. More men agreed that the parental newsletters provided new information. Students with a medium and high level of parental involvement ate 47.5 and 95.2 g more FV per day compared to students with low level/no parental involvement (p = 0.02). CONCLUSIONS: Students with a high level of parental involvement ate significantly more FV at follow-up compared to students with a low level/no parental involvement. Parental involvement in interventions may improve adolescents' FV intake if challenges of implementation can be overcome. TRIAL REGISTRATION: ISRCTN11666034 . Registered 06/01/2012. Retrospectively registered.

Fast-food intake and perceived and objective measures of the local fast-food environment in adolescents.

OBJECTIVE: We examined associations between fast-food intake and perceived and objective fast-food outlet exposure. DESIGN: Information from the Health Behaviours in School-aged Children Study was linked to fast-food outlets in seventy-five school neighbourhoods. We used multivariate multilevel logistic regression analyses to examine associations between at least weekly fast-food intake and perceived and objective fast-food outlet measures. SUBJECTS: Data represent 4642 adolescents (aged 11-15 years) in Denmark. RESULTS: Boys reporting two or more fast-food outlets had 34% higher odds consuming fast food at least weekly. We detected higher odds of at least weekly fast-food intake among 15-year-old 9th graders (ORall=1.74; 95% CI 1.40, 2.18; ORboys=2.20; 95% CI 1.66, 2.91; ORgirls=1.41; 95% CI 1.03, 1.92), Danish speakers (ORall=2.32; 95% CI 1.68, 3.19; ORboys=2.58; 95% CI 1.69, 3.93; ORgirls=2.37; 95% CI 1.46, 3.84) and those travelling 15 min or less to school (ORall=1.21; 95% CI 1.00, 1.46; ORgirls=1.44; 95% CI 1.08, 1.93) compared with 11-year-old 5th graders, non-Danish speakers and those with longer travel times. Boys from middle- (OR=1.28; 95% CI 1.00, 1.65) and girls from low-income families (OR=1.46; 95% CI 1.05, 2.04) had higher odds of at least weekly fast-food intake compared with those from high-income backgrounds. Girls attending schools with canteens (OR=1.47; 95% CI 1.00, 2.15) had higher odds of at least weekly fast-food intake than girls at schools without canteens. CONCLUSIONS: The present study demonstrates that perceived food outlets may impact fast-food intake in boys while proximity impacts intake in girls. Public health planning could target food environments that emphasize a better understanding of how adolescents use local resources.

Lunch frequency among adolescents: associations with sociodemographic factors and school characteristics.

OBJECTIVE: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch frequency and school characteristics vary by gender and age groups. DESIGN: Cross-sectional study in which students and school headmasters completed self-administered questionnaires. Associations were estimated by multilevel multivariate logistic regression. SETTING: The Danish arm of the Health Behaviour in School-Aged Children study 2010. SUBJECTS: Students (n 4922) aged 11, 13 and 15 years attending a random sample of seventy-three schools. RESULTS: The school-level and class-level variations in low lunch frequency were small (intraclass correlation coefficient <2·1 %). At the individual level, low lunch frequency was most common among students who were boys, 13- and 15-year-olds, from medium and low family social class, descendants of immigrants, living in a single-parent family and in a reconstructed family. School-level analyses suggested that having access to a canteen at school was associated with low lunch frequency (OR=1·47; 95% CI 1·14, 1·89). Likewise not having an adult present during lunch breaks was associated with low lunch frequency (OR=1·44; 95% CI 1·18, 1·75). Cross-level interactions suggested that these associations differed by age group. CONCLUSIONS: Lunch frequency among Danish students appears to be largely influenced by sociodemographic factors. Additionally, the presence of an adult during lunch breaks promotes frequent lunch consumption while availability of a canteen may discourage frequent lunch consumption. These findings vary between older and younger students.

Health promotion in primary and secondary schools in Denmark: time trends and associations with schools' and students' characteristics.

BACKGROUND: Schools are important arenas for interventions among children as health promoting initiatives in childhood is expected to have substantial influence on health and well-being in adulthood. In countries with compulsory school attention, all children could potentially benefit from health promotion at the school level regardless of socioeconomic status or other background factors. The first aim was to elucidate time trends in the number and types of school health promoting activities by describing the number and type of health promoting activities in primary and secondary schools in Denmark. The second aim was to investigate which characteristics of schools and students that are associated with participation in many (≥3) versus few (0-2) health promoting activities during the preceding 2-3 years. METHODS: We used cross-sectional data from the 2006- and 2010-survey of the Health Behaviour in School-aged Children study. The headmasters answered questions about the school's participation in health promoting activities and about school size, proportion of ethnic minorities, school facilities available for health promoting activities, competing problems and resources at the school and in the neighborhood. Students provided information about their health-related behavior and exposure to bullying which was aggregated to the school level. A total of 74 schools were available for analyses in 2006 and 69 in 2010. We used chi-square test, t-test, and binary logistic regression to analyze time trends and differences between schools engaging in many versus few health promoting activities. RESULTS: The percentage of schools participating in ≥3 health promoting activities was 63% in 2006 and 61% in 2010. Also the mean number of health promoting activities was similar (3.14 vs. 3.07). The activities most frequently targeted physical activity (73% and 85%) and bullying (78% and 67%). Schools' participation in anti-smoking activities was significantly higher in 2006 compared with 2010 (46% vs. 29%). None of the investigated variables were associated with schools' participation in health promoting activities. CONCLUSION: In a Danish context, schools' participation in health promotion was rather stable from 2006 to 2010 and unrelated to the measured characteristics of the schools and their students.

Implementation of strategies to increase adolescents' access to fruit and vegetables at school: process evaluation findings from the Boost study.

BACKGROUND: Access to fruit and vegetables (FV) is associated with adolescents' FV consumption. However, little is known about implementation of strategies to increase access to FV at schools. We examined the implementation of two environmental components designed to increase access to FV at Danish schools. METHODS: We used data from 20 intervention schools involved in the school-based multicomponent Boost trial targeting 13-year-olds' FV consumption. The environmental components at school included daily provision of free FV and promotion of a pleasant eating environment. Questionnaire data was collected by the end of the nine-month intervention period among 1,121 pupils (95%), from all school principals (n = 20) and half way through the intervention period and by the end of the intervention among 114 teachers (44%). The implementation of the components was examined descriptively using the following process evaluation measures; fidelity, dose delivered, dose received and reach. Schools with stable high implementation levels over time were characterised by context, intervention appreciation and implementation of other components. RESULTS: For all process evaluation measures, the level of implementation varied by schools, classes and over time. Dose received: 45% of pupils (school range: 13-72%, class range: 7-77%) ate the provided FV daily; 68% of pupils (school range: 40-93%, class range: 24-100%) reported that time was allocated to eating FV in class. Reach: The intake of FV provided did not differ by SEP nor gender, but more girls and low SEP pupils enjoyed eating FV together. Dose delivered: The proportion of teachers offering FV at a daily basis decreased over time, while the proportion of teachers cutting up FV increased over time. Schools in which high proportions of teachers offered FV daily throughout the intervention period were characterized by being: small; having a low proportion of low SEP pupils; having a school food policy; high teacher- and pupil intervention appreciation; having fewer teachers who cut up FV; and having high implementation of educational components. CONCLUSIONS: The appliance of different approaches and levels of analyses to describe data provided comprehension and knowledge of the implementation process. This knowledge is crucial for the interpretation of intervention effect. TRIAL REGISTRATION: Current Controlled Trials ISRCTN11666034.

The role of curriculum dose for the promotion of fruit and vegetable intake among adolescents: results from the Boost intervention.

BACKGROUND: Multi-component interventions combining educational and environmental strategies have proved effective in increasing children and adolescents' fruit and vegetable intake. However such interventions are complex and difficult to implement and several studies report poor implementation. There is a need for knowledge on the role of dose for behaviour change and for assessment of intervention dose to avoid conclusions that intervention components which are not implemented are ineffective. This study aimed to examine 1) the association between dose of a class curriculum and adolescents' fruit and vegetable intake in a school-based multi-component intervention, 2) if gender and socioeconomic position modify this association. METHODS: We carried out secondary analysis of data from intervention schools in the cluster-randomized Boost study targeting 13-year-olds' fruit and vegetable intake. Teacher- and student data on curriculum dose delivered and received were aggregated to the school-level and class-level (only possible for student data). We analysed the association between curriculum dose and students' (n 995) self-reported fruit and vegetable intake (24-h recall questionnaire) after finalization of the intervention using multi-level analyses. Potential moderation was examined by analyses stratified by gender and socioeconomic position. RESULTS: Average dose received at class-level was significantly associated with students' fruit and vegetable intake (10 g (CI: 0.06, 20.33) per curricular activity received). In stratified analyses the association remained significant among boys only (14 g (CI: 2.84, 26.76) per curricular activity received). The average dose delivered and received at the school-level was not significantly associated with students' intake. CONCLUSIONS: We found a dose-response relationship between number of curricular activities received and adolescents' fruit and vegetable intake. The results indicate that curriculum dose received only mattered for promotion of fruit and vegetable intake among boys. Future studies should explore this gender difference in larger samples to guide the planning of school-based curricular interventions with regards to the optimal number of curricular activities required to promote behavioural change in subgroups with low fruit and vegetable intake at baseline. TRIAL REGISTRATION: Current Controlled Trials ISRCTN11666034.

Fruit and vegetable consumption trends among adolescents from 2002 to 2010 in 33 countries.

BACKGROUND: Fruit and vegetable consumption is linked to many positive health outcomes, nevertheless many adolescents do not consume fruit and vegetables on a daily basis. METHODS: Data of 488,951 adolescents, aged 11-, 13- and 15- years, from 33 mainly European and North American countries/regions participating in the cross-sectional Health Behaviour in School-aged Children surveys in 2002, 2006 and 2010, were used to investigate trends in daily fruit and vegetable consumption between 2002 and 2010. RESULTS: Multilevel logistic regression analyses showed an increase in daily fruit and vegetable consumption between 2002 and 2010 in the majority of countries for both genders and all three age groups. A decrease in consumption was noticed in five countries for fruit and five countries for vegetables. CONCLUSION: Overall, a positive trend was noticed, however increases in daily fruit and vegetable consumption are still indicated.

Trend analyses in the health behaviour in school-aged children study: methodological considerations and recommendations.

BACKGROUND: This article presents the scope and development of the Health Behaviour in School-aged Children (HBSC) study, reviews trend papers published on international HBSC data up to 2012 and discusses the efforts made to produce reliable trend analyses. METHODS: The major goal of this article is to present the statistical procedures and analytical strategies for upholding high data quality, as well as reflections from the authors of this article on how to produce reliable trends based on an international study of the magnitude of the HBSC study. HBSC is an international cross-sectional study collecting data from adolescents aged 11-15 years, on a broad variety of health determinants and health behaviours. RESULTS: A number of methodological challenges have stemmed from the growth of the HBSC-study, in particular given that the study has a focus on monitoring trends. Some of those challenges are considered. When analysing trends, researchers must be able to assess whether a change in prevalence is an expression of an actual change in the observed outcome, whether it is a result of methodological artefacts, or whether it is due to changes in the conceptualization of the outcome by the respondents. CONCLUSION: The article present recommendations to take a number of the considerations into account. The considerations imply methodological challenges, which are core issues in undertaking trend analyses.

Implementing a free school-based fruit and vegetable programme: barriers and facilitators experienced by pupils, teachers and produce suppliers in the Boost study.

BACKGROUND: Multi-component interventions which combine educational and environmental strategies appear to be most effective in increasing fruit and vegetable (FV) intake in adolescents. However, multi-component interventions are complex to implement and often poorly implemented. Identification of barriers and facilitators for implementation is warranted to improve future interventions.This study aimed to explore implementation of two intervention components which addressed availability and accessibility of FV in the multi-component, school-based Boost study which targeted FV intake among Danish 13-year-olds and to identify barriers and facilitators for implementation among pupils, teachers and FV suppliers. METHODS: We conducted focus group interviews with 111 13-year-olds and 13 teachers, completed class observations at six schools, and conducted telephone interviews with all involved FV suppliers. Interviews were transcribed, coded and analysed using qualitative analytical procedures. RESULTS: FV suppliers affected the implementation of the FV programme at schools and thereby pupils' intake through their timing of delivery and through the quality, quantity and variety of the delivered FV. Teachers influenced the accessibility and appearance of FV by deciding if and when the pupils could eat FV and whether FV were cut up. Different aspects of time acted as barriers for teachers' implementation of the FV programme: time spent on having a FV break during lessons, time needed to prepare FV and time spent on pupils' misbehaviour and not being able to handle getting FV. Teacher timing of cutting up and serving FV could turn into a barrier for pupils FV intake due to enzymatic browning. The appearance of FV was important for pupils' intake, especially for girls. FV that did not appeal to the pupils e.g. had turned brown after being cut up were thrown around as a part of a game by the pupils, especially boys. Girls appreciated the social dimension of eating FV together to a larger extent than boys. CONCLUSIONS: Limited time and pupils' misbehaviour were barriers for teachers' implementation. Establishing FV delivery to schools as a new routine challenged FV suppliers' implementation. Food aesthetics were important for most pupils' FV intake while the social dimension of eating FV together seemed more important to girls than boys. TRIAL REGISTRATION: Current Controlled Trials ISRCTN11666034.

Do school-based smoking preventive interventions have unintended effects? Post hoc analysis of the Focus cluster randomised controlled trial.

OBJECTIVES: Public health interventions are designed to improve specific health-related outcomes; however, they may also produce negative side effects, such as substitution use, psychological or social harms. Knowledge about the unintended effects of school-based smoking preventive interventions is sparse. Hence, this study examined these potential unintended effects of the smoking-reducing intervention, Focus, among students in the vocational education and training setting. DESIGN: Cluster randomised controlled trial stratified by school type with 5 months follow-up. SETTING AND PARTICIPANTS: Across Denmark, eight schools were randomised to the intervention group (n=844 students, response proportion 76%) and six schools to the control group (n=815 students, response proportion 75%). This study focused solely on students who smoked at baseline (N=491). INTERVENTIONS: The intervention was developed systematically based on theory and a thoroughly mixed-methods needs assessment. Intervention components included a comprehensive school tobacco policy (smoke-free school hours) supported by a 3-day course for school staff and launched by an edutainment session for students; class-based lessons and a quit-and-win competition; and individual telephone smoking cessation support. OUTCOMES: Alternative tobacco and nicotine products (regular use of smokeless tobacco, hookah and e-cigarettes), regular cannabis use, boredom and loneliness at school, stress and perceived stigmatisation among smokers. RESULTS: We found no statistically significant unintended effects of the intervention. Nonetheless, insignificant findings indicated that students in the intervention group were less likely to be bored during school hours (OR 0.59, 95% CI 0.32 to 1.10) and experience stress (OR 0.62, 95% CI 0.35 to 1.10), but more likely to report feeling stigmatised compared with the control group (OR 1.55, 95% CI 0.71 to 3.40). CONCLUSIONS: Overall, findings suggested no unintended effects of the Focus trial with respect to substitution use, psychological, nor group or social harms. Future research is encouraged to report potential harmful outcomes of smoking preventive interventions, and interventions should be aware of the possible stigmatisation of smokers. TRIAL REGISTRATION NUMBER: ISRCTN16455577.

Developing and Evaluating a Data-Driven and Systems Approach to Health Promotion Among Vocational Students: Protocol for the Data Health Study.

BACKGROUND: Vocational school students exhibit significant risk behaviors in terms of poor diet, frequent use of nicotine products, inadequate fruit and vegetable intake, low levels of physical activity, and poor mental health. This makes vocational students vulnerable to the development of noncommunicable diseases. Therefore, effective health promotion programs targeting vocational students are required. OBJECTIVE: The Danish study "Data-driven and Systems Approach to Health Promotion Among Vocational Students" (Data Health) aims to develop, implement, and evaluate a systems approach to support vocational schools, municipalities, and local communities in implementing locally relevant health promotion actions among and for vocational students. This paper describes the Data Health program and how implementation and preliminary effectiveness will be evaluated. METHODS: The Data Health program offers an iterative 5-step process to develop changes in the systems that shape health behavior and well-being among vocational students. The program will be implemented and evaluated in 8 Danish vocational schools in 4 municipalities. The implementation of the process and actions will be explored using a systems-based evaluation design that assesses contextual differences and the mechanisms through which the program leads to changes in the systems. Preliminary effectiveness at the individual level (students' self-reported health behavior and well-being) and organizational level (school organizational readiness reported by school staff) will be assessed using a quasi-experimental design, and cross-sectional data will be collected at all 8 schools simultaneously 4 times during the 2-year study period. RESULTS: This study was launched in 2021, and data collection is expected to be completed in June 2024. The first results are expected to be submitted for publication in January 2024. CONCLUSIONS: We expect that the Data Health study will make significant contributions to complex intervention research by contributing to the paucity of research studies that have used systems approaches in school settings. The study will also provide evidence of successful elements for systems change and effectiveness to determine whether a national scale-up can be recommended. TRIAL REGISTRATION: ClinicalTrials.gov NCT05308459; https://clinicaltrials.gov/study/NCT05308459. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/52571.