Generation Healthy Kids: A Cluster-randomized Trial of a Multi-component, Multi-setting Intervention to Promote Healthy Weight and Wellbeing in Danish School-aged Children
Phase: NA
Conditions: Childhood Obesity, Well-Being, Psychological, Physical Inactivity, Sleep, Screen Time, Diet Habit
Sponsor: University of Copenhagen

 
 
CONFIDENTIAL 
STØTTET AF     
 
  
 
 
Generation Healthy Kids 
Main study 
 
[Generation Sunde Børn - hovedstudie] 
 
 
Version: 1.1 
Date: 6 March 2023 

 
 
1 Responsible parties 
Principal Investigator:   
Professor, Jens Troelsen 
Head of Department of Sports Science and Clinical Biomechanics 
Faculty of Health Sciences, University of Southern Denmark  
Campusvej 55, 5230 Odense M, Denmark 
Phone: + 45 65 50 34 93 
E-mail: JTroelsen@health.sdu.dk  
 
 
Co-PI 
 
Professor, Nikolai Baastrup Nordsborg 
 
Head of Department of Nutrition, Exercise and Sports 
 
University of Copenhagen 
 
Nørre Allé 51, 2200 København N, Denmark 
Phone: + 45 35 32 16 12, 
E-mail: nbn@nexs.ku.dk  
 
Investigators: 
Professor, Ulla Toft 
Center for Clinical Research and Prevention 
Bispebjerg and Frederiksberg Hospital 
Nordre Fasanvej 57 
2000 Frederiksberg, Denmark 
Phone: +45 29 99 78 77 
E-mail: Ulla.toft@regionh.dk  
 
Associate Professor, Camilla Trab Damsgaard 
Department of Nutrition Exercise and Sports 
Faculty of Science, University of Copenhagen 
Rolighedsvej 26, 1958 Frederiksberg C, Denmark 
Phone: +4535332221 
E-mail: ctd@nexs.ku.dk 
 
Professor, Peter Krustrup 
Department of Sports Science and Clinical Biomechanics 
Faculty of Health Sciences, University of Southern Denmark 
Campusvej 55, 5230 Odense M, Denmark 
Phone: +45 21 16 15 30   
E-mail: pkrustrup@health.sdu.dk 
 
Professor, Anders Grøntved 
Department of Sports Science and Clinical Biomechanics 

 
 
CONFIDENTIAL 
 
Faculty of Health Sciences, University of Southern Denmark 
Campusvej 55, 5230 Odense M, Denmark 
Phone: +45 65 50 44 65  
E-mail: agroentved@health.sdu.dk   
 
Senior Research Fellow, Rikke Fredenslund Krølner 
Centre for Intervention Research  
University of Southern Denmark/National Institute of Public Health  
Studiestræde 6, 1455 Copenhagen K  
Phone: +45 65 50 78 41  
E-mail: rikr@sdu.dk   
 
GCP coordinator: 
Le Lene Susanne Simon Stevner 
Department of Nutrition, Exercise and Sports,  
Faculty of Science, University of Copenhagen 
Rolighedsvej 26, 1958 Frederiksberg C, Denmark 
Phone: +45 3533 2371 
E-mail: less@nexs.ku.dk  
 
Medical Expert and Clinically Responsible Physician: 
Professor, MD, Christian Mølgaard 
Department of Nutrition, Exercise and Sports,  
Faculty of Science, University of Copenhagen 
Rolighedsvej 26, 1958 Frederiksberg C, Denmark 
Phone: +45 35 33 25 16 
E-mail: cm@nexs.ku.dk 
 
 
 

 
 
 
 
 
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2 Table of Contents 
 
1 
Responsible parties 
2 
2 Table of Contents 
4 
3 Abbreviations and Definition of Terms 
7 
4 Background 
8 
5 Study Objectives 
12 
5.1 Overall Objective 
12 
5.2 Specific Objectives 
12 
6 Investigational Plan 
14 
6.1 Study Design 
14 
6.1.1 Justification of study design 
14 
6.1.2 Randomization 
14 
6.1.3 Timeframe of the trial 
14 
6.1.4 Sample size justification 
15 
6.1.5 Blinding 
15 
6.2 Study Participants 
16 
6.2.1 Inclusion Criteria 
16 
6.2.2 Exclusion Criteria 
16 
6.2.3 Withdrawal Criteria 
16 
6.2.4 Recruitment of schools 
17 
6.2.5 Recruitment and enrolment of study participants 
18 
6.3 Intervention 
21 

 
 
 
 
 
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6.3.1 Principles of the intervention 
21 
6.3.2 Interventions in schools and after-school clubs 
23 
6.3.3 Interventions focused on the child through the family 
26 
6.3.4 Intervention focused on the local environment 
29 
6.3.5 Compliance 
29 
6.4 Control schools 
30 
6.5 Overview of study procedures and activities 
30 
6.6 Measurements and study procedures 
33 
6.6.1 Questionnaires to be filled in at home 
33 
6.6.2 Other procedures at home 
34 
6.6.3 Measurements in school 
35 
6.6.4 Evaluation of measures related to implementation of the intervention and 
organizational aspects 
38 
6.6.5 Measurements at further school, community, and national level 
39 
6.6.6 Use of the school’s recordings of children’s absence 
40 
6.7 Adverse Events 
40 
6.8 Handling of biological samples 
40 
6.8.1 Sample analysis 
40 
6.8.2 Genotypes and epigenetic analyses 
42 
6.8.3 Research Biobank 
42 
6.8.4 Biobank for future research purposes 
42 
6.9 Data Management and Quality Control 
43 

 
 
 
 
 
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6.10 Use of data from Danish registers 
44 
6.11 Statistical methods 
45 
6.12 Suspension or early termination of the study 
47 
6.13 Serious adverse events and reporting 
47 
6.13.1 Serious adverse events 
47 
6.13.2 Reporting of Serious adverse events 
48 
6.14 Study Documentation 
48 
6.14.1 Publication of Results 
48 
7 Ethical conducts of the study 
48 
7.1 Ethical approval and study registration 
49 
7.2 Justification of the study 
49 
7.3 Underage study participants - justification and precautions 
49 
7.4 Children of ethnic minority 
49 
7.5 Risks and safety in relation to conducting the study 
50 
7.6 Benefits of the study and risk-benefit evaluation 
51 
7.7 Participant Information and Informed Consent 
52 
7.8 Protocol Changes 
52 
7.9 Protocol Deviations 
52 
7.9 Insurance 
53 
8 Funding 
53 
9 References 
54 
10 List of Appendices (all in Danish) 
65 
 

 
 
 
 
 
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3 Abbreviations and Definition of Terms 
AE
BMI 
CAPL 
CCRP 
CRF 
DAPL 
FM 
GDPR 
LCPG 
MVPA 
NEXS 
PA 
PE 
PL 
SDU 
SES 
SFO 
UCPH 
VPA 
Adverse Event
Body Mass Index 
Canadian Assessment of Physical Literacy 
Center for Clinical Research and Prevention 
Case Report Form 
Danish Assessment of Physical Literacy 
Fat mass 
General Data Protection Regulation 
Local Community Partnership Group 
Moderate to Vigorous Physical Activity 
Department of Nutrition, Exercise and Sports 
Physical Activity 
Physical Education 
Physical Literacy 
University of Southern Denmark 
Socioeconomic Status 
After School Club 
University of Copenhagen 
Vigorous Physical Activity 
 

 
 
 
 
 
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4 Background 
4.1 The global problem of overweight and obesity  
Overweight and obesity among children is a global problem affecting more than 41 million children 
under the age of 5 years. The World Health Organization (WHO) describes childhood obesity as one of 
the most serious public health challenges worldwide for the 21st century (1,2). The prevalence of 
overweight and obesity in Danish children is 12-13% in primary school and increases to 18-19% at the 
time of graduation (3), why early prevention is important. In the adult population 51% are estimated 
to be overweight or obese (4,5).  
Overweight and obesity have many negative health consequences for children during their early years 
and in later life. For instance, children who have overweight or obesity are more likely to experience 
bullying, stigmatization and suffer from low self-esteem, anxiety, and lower quality of life (6). In 
addition, children with overweight and obesity have an increased risk of overweight and obesity as 
adults, which is well known to lead to poorer health and well-being and marked economic negative 
effects for the individual and for society.  
There are stark inequalities in the prevalence of childhood overweight, both worldwide and in 
Denmark, contributing to the health inequality found in most countries (4,7). In Denmark, the 
overweight prevalence among children aged 6-7 years in high-income families is 11% compared to 26% 
in low-income families. Among children aged 14-15 years, the prevalence of overweight is almost 30% 
in families with short education compared to 10% among those from families with long education (8).  
Many trials have been conducted to reduce childhood overweight and obesity, and several 
comprehensive systematic reviews have investigated the effect of different interventions in preventing 
childhood overweight and obesity (9–16). However, most of the earlier studies find no or only small 
effects on children’s body mass index (BMI), and the evidence of long-term effects is limited. 
Thus, there is a strong need to develop new innovative approaches and programs that effectively can 
prevent overweight among all children, starting early in life and embedding promising programs and 
integrated approaches into everyday practices.  
4.2 Important characteristics to increase likelihood of success  
Some of the earlier studies did show a significant effect on overweight measures. Across these 
studies, some characteristics and elements seem to increase the likelihood of success:  
 A multi-component, multi-setting intervention, including well-planned involvement of 
relevant stakeholders, is likely to yield the highest level of effect in promoting healthy 
weight in children (17,18).  

 
 
 
 
 
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 Multi-component interventions targeting two or more health behaviours (i.e., physical 
activity, dietary outcomes, sedentary behaviour, sleep) seems to be more successful 
in improving adiposity outcomes compared to single-component interventions (12–
14,19–24). Involving parents was found to be essential in the prevention of childhood 
overweight and obesity, especially among children younger than 12 years 
(9,11,13,23,25–29). However, less than half of the earlier studies involved parents (25). 
Among the studies that did involve parents, three out of four demonstrated positive 
outcomes in reducing BMI or weight status.  
Other characteristics that seem promising are: 
 Combining educational components (e.g. targeting the children’s knowledge, 
competences, literacy levels, and motivation) with environmental or structural 
components (e.g. free healthy school meals, smaller portion sizes, easy access to fruit 
and vegetables, physical activity as a part of the school day, free and/or easy access to 
leisure time activities, healthy space management of supermarkets, healthy 
alternatives in restaurants, decreased availability of fast food and sugary beverages, 
and healthy school policies) (9,13,16,28,29). The environment around the child, both 
at school and at leisure time (home and local community) must support healthy living.  
 Targeting a multitude of the settings where children spend their time (23,30) and 
including multiple intervention components (9–16). Several systematic reviews have 
shown limited effects of interventions that are purely school based (31).  
 Long-term interventions (twelve months or longer) appear to be more effective 
compared to studies of shorter duration (9,13). 
 Co-creation and involvement of relevant stakeholders was also found to be an 
important factor in earlier, successful studies. This means involving stakeholders in 
identifying, prioritizing, developing, and implementing interventions using co-creative 
approaches and capacity building processes (32–37).  (16,38,39).  
4.3 Key components in prevention - diet, physical activity, screen time and sleep  
Healthy diets and balanced energy intake are key factors in prevention of overweight in 
childhood, which must be addressed simultaneously in different settings for maximal effect, 
in a manner that supports food literacy, practical competence and long-term behaviour 
change via environmental changes. Danish children consume too little vegetables, 
wholegrains, and fish, and too much sugar and fat, compared to the Danish food-based 
guidelines and the Nordic Nutrition Recommendations (40–42). This worsens with age, which 
means that preventive efforts are needed at an early age. There is considerable social 
inequality in dietary behaviours, as Danish children from households with short compared to 
long education consume less fruits, vegetables, dietary fibre, and fish and often skip breakfast 

 
 
 
 
 
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(43). School food programs can improve dietary quality (44), and in Sweden, provision of free 
school lunches during basic school has been associated with long term effect on different 
indicators for better health and well-being, including education attainment, higher salaries, 
and higher final height later in life (45).  
The diet of Danish children has been found to be less healthy during weekends compared to 
weekdays (46), and studies have shown that children primarily learn about eating behaviour, 
dieting, cooking etc. by watching their parents. Further, parents define their children’s home 
food environment, e.g., access to healthy and unhealthy food items and whether there are 
family rules limiting the intake of unhealthy foods (47,48).  
Physical activity (PA) is an important part of a healthy lifestyle for children, as it improves 
physical fitness, motor competences and well-being, and reduces the risk of developing 
overweight and non-communicable diseases later in life (49). Current recommendations are 
that children and adolescents should participate in at least 60 minutes of moderate-to-
vigorous physical activity (MVPA) per day and 3x30 minutes of vigorous physical activity (VPA) 
per week. However, in Scandinavia and the rest of Europe, many children do not reach these 
targets (50,51).  
A high percentage (about 70 percent) of 7-9-year-old children in Denmark participate in one 
or more club-organized sports. This contributes significantly to these children’s MVPA and 
increases their chance of being active at a later age, when physically active free play during 
e.g., recess decreases. The participation rates, however, are much lower for children whose 
parents have low sporting experience and in families with limited socioeconomic resources. 
Excessive recreational screen media use and short- and poor-quality sleep are important risk 
factors for the development of childhood obesity (52,53). While high screen use may be 
obesogenic by displacing engagement in PA during leisure time, it may also lead to insufficient 
sleep among children (54). Sleep is not only critical for learning, memory, and school 
performance. Inadequate sleep also disrupts hormone levels that regulate appetite and food 
intake (53). A third of Danish 6-11-year-old children use screen media >4 hours/day during 
weekends, and 24% of children in this age group report screen use just before bedtime on all 
weekdays (7,55). Furthermore, significant socioeconomic disparity is seen in children’s screen 
media use, with higher prevalence of excessive recreational screen use and screen use just 
before bedtime in children from socioeconomic disadvantaged families. Insufficient sleep is 
also more common among children from families of low socioeconomic status (56). 
In addition, we observe that more healthy screen use practices appear to be promoted by 
well-established parental rules of screen media use hygiene (when to use screen media, 

 
 
 
 
 
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content- and amount of use), and we find a graded relationship of total recreational screen 
use, screen use just before bedtime and sleep time of children (57). 
4.4 Generation Healthy Kids – the innovative approach 
Generation Healthy Kids will build on the existing evidence, combining the characteristics and 
elements described above to improve the chance of success. The innovative aspects of the 
project are the combination of a randomized controlled trial targeting several important risk 
factors for excessive weight gain (dietary habits, physical activity, sleep, and screen time) with 
community capacity building and a systems approach (58). The unique combination is closely 
monitored for effect as well as process. The integrated intervention program will be unique in 
combining already tested effective intervention strategies with intervention components 
developed using co-creation and a systems mapping (58). Systems thinking will furthermore 
be used to ensure that a health equity lens is employed to understand the relationship 
between obesity and health inequalities locally (59). To reach children and families with low 
socio-economic status, focus will be on developing interventions that make healthy choices 
easy by creating healthy environments around the children, both at school and during leisure 
time. 
4.5 The pilot study and the main trial 
Generation Healthy Kids is a 4-year project including a pilot study which will be conducted in 
January-March 2023, and a 2-year cluster-randomized controlled main trial to be conducted 
in August 2023 – June 2025. The present protocol describes the main trial. 
The pilot study has previously been approved by The Regional Committee on Health Research 
Ethics for Southern Denmark (Project ID 568021-22 S-20220059). 
A thorough development and piloting is an essential prerequisite for ensuring feasibility and 
quality of the final intervention program to be assessed via the main trial. Based on the 
learnings and results from the pilot study, the final intervention program will be adjusted 
accordingly. Due to the timeline of the main trial, this protocol is submitted before the pilot 
study is conducted. Adjustments based on learnings and results from the pilot study will be 
included in amendment(s) to the Committee for change of the present protocol.  

 
 
 
 
 
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5 Study Objectives  
5.1 Overall Objective  
Generation Healthy Kids is a cluster-randomized community trial in which 24 local 
communities will be randomly allocated to intervention or control. The overall study objective 
is to investigate if a 2-school-year multi-setting, multi-component intervention focusing on 
healthy diets, physical activity, sleep and screen media habits in the local community can 
promote healthy weight and body composition in children who are in 1st and 2nd grade at 
inclusion (i.e., age 6–9 years at inclusion). We will also investigate the intervention’s effects 
on dietary intake and nutritional status; food competences; physical literacy, activity levels, 
and fitness; sleep and screen media habits; growth; cardio metabolic health; cognitive and 
motor functions; school performance; and mental health and wellbeing. Furthermore, we will 
evaluate the implementation of the intervention. 
In continuation of the above, we will investigate if the intervention can reduce social inequality 
in the outcomes, as well as explore potential effect modifiers such as sex, ethnicity, genetics, 
epigenetics etc. We will also explore associations between sociodemographic characteristics, 
health behaviours and outcomes cross-sectionally and longitudinally and use these data to 
validate and compare relevant measurement tools.  
The primary outcome is fat mass (FM) in kg. We hypothesize that the combined intervention 
components will counter the development of increasing overweight and unhealthy weight 
with age and thus will cause less FM gain in the intervention group compared with the control 
group. 
5.2 Specific Objectives 
5.2.1 Main objective 
The main objective is to investigate the impact of the 2-school-year intervention program on 
development of FM in the intervention group compared with the control group. 
5.2.2 Secondary objectives 
As secondary objectives, we will investigate the impact of the intervention program after 1 
and 2 years on: 

 
 
 
 
 
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- 
Other body composition measures, including fat free mass (FFM), FFM index, FM 
index, FFM-to-FM ratio, % FM; 
- 
Anthropometric measures and growth, including BMI z-score, prevalence of obesity, 
overweight, normal weight and underweight, waist circumference, linear growth and 
growth-related biomarkers; 
- 
Cardio metabolic health, including blood pressure, blood lipid profile, insulin resistance 
markers; 
- 
Other health related outcomes, including inflammation; 
- 
Cognitive and motor functions, physical literacy, and school performance; 
- 
Mental health and wellbeing;  
- 
Dietary intake, biomarkers of food and nutrient intake and status and appetite and 
food competence; 
- 
Physical activity, physical fitness, leisure-time activities, sleep- and screen media 
habits; 
- 
Long-term (>2 years) body composition based on height and weight obtained from 
routine data in The National Child Health Register (Børnedatabasen).   
Also, the collected data will be used for validations of associations between biological 
mechanisms and various measurements and outcomes (data analysed as observational data - 
i.e., based on baseline data, longitudinal data or using the data from the control group only), 
as well as the impact of background characteristics, such as socioeconomic position, family 
characteristics, sex, ethnicity, genetics, and epigenetics etc. on the effectiveness of the 
intervention. 
A specific objective of Generation Healthy Kids is to involve relevant local and national 
partners in the development and implementation of the multi-component intervention 
program, and to create local engagement and ownership for the implementation of the 
intervention. The project will work with multiple public, private and non-governmental 
organizations in the local community, including leisure time- and sports organizations, 
supermarkets, restaurants, and fast-food chains, to create healthier environments, e.g., by 
increasing access to healthy foods in supermarkets. The effects of such initiatives will be 
monitored and evaluated by e.g., sales data from supermarkets. 
In addition, an objective of the study is to understand and document implementation-related 
factors, causal mechanisms and contextual factors which shape the intervention’s outcomes. 
Therefore, a thorough process evaluation will be conducted, see section 6.5.4. 
A protocol résumé is found in Appendix 1. 

 
 
 
 
 
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6 Investigational Plan 
6.1 Study Design 
The study will be designed as a community-based open label cluster randomized superiority 
trial with two arms (intervention and control). Individual school districts will form the basis of 
the cluster. A comprehensive list of public schools (“folkeskoler”) will form the school district 
sampling frame, which is further explained in section 6.2.4. Teachers and pedagogues at each 
school will have a key role in implementing, coordinating, and anchoring the intervention.  
6.1.1 Justification of study design  
The study is designed as an open label cluster randomized trial as the primary objective of the 
study is to examine the effectiveness of the Generation Healthy Kids Program on the primary 
and secondary outcomes specified in sections 5.1 and 5.2.  
6.1.2 Randomization 
In this cluster-randomized trial, randomization will occur at school district level and will be 
performed prior to inclusion of participants (i.e., children) and collection of informed consent. 
A stratified block randomization will be carried out in a 1:1 ratio. To prevent baseline 
imbalance of cluster characteristics across the two study arms, we will use covariate-
constrained randomization (60). The covariates will be at school- and school district level with 
tentative factors being number of classes per school year (at least two classes per school year 
required); the socioeconomic profile of the school based on parental educational level 
(proportion of parents with a shorter education); ethnicity of the children (proportion of pupils 
with non-Danish origin in the respective school); and degree of urbanization of school district. 
The randomization procedure will be carried out by a statistician not otherwise involved in the 
project (i.e., not involved in recruitment of school districts or participants), and the procedure 
will be concealed to the investigators. 
6.1.3 Timeframe of the trial 
The trial will run over two school years (2023-24 and 2024-25). Baseline data will be obtained 
before the start of the intervention, and follow-up data will be collected during the two school 
years period.  

 
 
 
 
 
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6.1.4 Sample size justification 
The sample size calculations are based on the primary outcome for the study being FM (kg) at 
22 months as measured by air displacement plethysmography (BODPOD). For the power 
calculation, a mean cluster size of n=90 children is assumed, which we expect based on our 
inclusion criteria of ≥2 classes per school year, an anticipated mean of 20 enrolled children per 
class, and a drop-out/missing data of 15%. Others and we have managed to limit missing data 
to approximately this amount in previous large-scale school-based cluster randomized trials 
in young people (61–63). Thus, we aim to enrol a mean of n=105 children from each school 
district. We assume a cluster size coefficient of variation of 0.24 based on the OPUS School 
Meal Study (64) PHASAR data (65) (1st to 4th grade children), a standard deviation of FM of 
4.65 kg in both groups based on OPUS, and a conservative estimate of the intra-cluster 
correlation coefficient in FM (kg) of 0.03 based on PHASAR data (PI´s of the OPUS and PHASAR 
study are part of the scientific team in Generation Healthy Kids). Finally, because we plan to 
adjust for baseline FM (kg) in our primary analysis, we also assume a correlation between 
baseline and follow-up FM (kg) of 0.8 in the power calculation. With an expected enrolment 
of 24 clusters in 1:1 ratio allocation to intervention and control, we have decided to 
additionally control for type-1 error due to a planned correction of small (cluster) sample using 
the Satterthwaite correction for mixed linear models (66) by lowering alpha to 0.025 in the 
power calculations. With a cluster size of 90 and 24 clusters (expected n=2,160 children in the 
analytical sample and 2,520 enrolled children at baseline), we have a power of 80% to detect 
a significant mean difference of -0.76 kg FM or greater at 22 months between intervention 
and control. In OPUS data, this difference corresponds to -0.15 BMI-z score (95% CI -0.144; -
0.158), and a previous cohort study based on The Copenhagen School Health Records Register 
reported that a 1 kg increase in FM at 10 years of age was associated with a 12% and 15% 
increased risk of type 2 diabetes at 50 years of age for boys and girls, respectively (67), which 
corresponds to an 8% and 10% decrease in risk per -0.76 kg FM. Thus, the planned study is 
powered to detect a fairly small, but also clinically relevant size of mean difference in FM at 
22 months between intervention and control. 
6.1.5 Blinding 
The study will be open label, as it will not be possible to blind participants due to the nature 
of the intervention. Also, it is not possible to blind personnel delivering the intervention (i.e., 
teachers). Outcome assessors will not be blinded, as we judge this to be impossible to 
implement with success. However, the primary outcome (FM) is objectively assessed not 
involving judgement by the assessor during the assessment and therefore unlikely to be 
influenced by knowledge of intervention allocation. 

 
 
 
 
 
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6.2 Study Participants 
The study population will be approximately 2,500-2,600 children in 1st and 2nd grade (i.e., 
age 6–9 years at baseline) who attend public schools in 24 school districts from selected 
municipalities.   
We have selected young school children as the target group for the intervention, because the 
prevalence of overweight and obesity increases from early childhood until adolescence, from 
approximately 12-13% at ages 6-7 years to approximately 18-19% at ages 14-15 years (68–72). 
Furthermore, early childhood is an important time period for formation of habits in relation 
to diet and physical activity which may persist into adulthood (73). Thus, early intervention is 
crucial to prevent unhealthy weight development. 
6.2.1 Inclusion Criteria 
All children attending 1st or 2nd grade in schools recruited into the study will be eligible to 
participate. 
6.2.2 Exclusion Criteria 
There are no exclusion criteria for the children. If a child has food allergies, plaster allergies, 
or chronical disease (Appendix 2a and 2b) or if parents, teachers, or research team judge that 
a child has physical or mental disabilities which cannot be accommodated in the dietary or 
physical interventions, the child can participate in the remaining parts of the program.  
6.2.3 Withdrawal Criteria 
The parents will be informed that they can withdraw their child from the study at any time 
and for whatever reason without any explanation or consequences for the child's daily life at 
school. If parents withdraw their child, they will be asked if they are willing to explain the 
reason, but the response is optional, i.e., entirely voluntary (see Appendix 3). In case of 
participant withdrawal, the data collected up to the point of withdrawal will be used in data 
analyses. Withdrawn participants will not be replaced.  
The Primary Investigator and Clinical Responsible Physician (independently of each other) 
have the right and obligation to terminate participation of any child at any time if it is deemed 
to be in the best interest of the child, e.g.:  
 If a child’s safety or well-being is compromised by further participation 

 
 
 
 
 
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 If the investigator judges that the child does not want to continue his/her participation 
 
Or in the interest of completion of the study, e.g.: 
 If the child does not comply with the study procedures in a way that impacts the 
scientific integrity of the study. 
 Reasons for withdrawal will be recorded, and parents will be informed about the 
decision.  
Dropouts and children who do not participate in the study will not be excluded from 
participating in activities which are incorporated as a part of the school’s regular schedule and 
activities, including physical activity during school time, school meals, and learning activities 
during school time regarding screen media habits, sleep habits and food competences. 
However, no data will be collected from these children.  
6.2.4 Recruitment of schools 
The sampling frame of the study will be constructed based on information on all public schools 
(“folkeskoler”) in Denmark obtained from The Danish Ministry of Children and Education data-
warehouse. Information obtained at school-level will include the number of children attending 
each school in 1st and 2nd grade. Special schools and schools in areas that already take part 
in similar research projects will not be eligible for participation. An initial sampling frame list 
will prioritize schools with at least two classes per year group and relative geographical 
proximity to the study centres. This sampling frame list will be expanded if the success of 
recruiting schools is lower than expected. To minimize contamination, eligible school districts 
are not allowed to lie geographically next to each other.  
The schools selected to be part of the sampling frame will be contacted directly via the school 
leader and the head of the school board, and the school will be invited to participate in the 
study. Furthermore, municipalities will be contacted to assist with recruitment of schools and 
to ensure overall support for the study. Finally, in addition to this direct recruitment 
procedure, an open advertisement for the study will be placed on relevant platforms (e.g., 
Folkeskolen.dk) to recruit potentially interested schools for the study. 

 
 
 
 
 
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6.2.5 Recruitment and enrolment of study participants 
6.2.5.1 Invitations 
Families in the selected schools and classes will receive invitations to the study through Aula 
or E-boks and in printed form from teachers. Aula is an online communication platform used 
by all schools and approved for the processing of sensitive information.  
The invitation message on Aula or E-boks will include: 
 An invitation letter, including an invitation to information meetings about the study at 
the school (Appendix 4A and 4B);  
 Written participant information about the study (Appendix 5A and 5B);  
 Informed consent form (standard form S6) (Appendix 6) 
 The 
pamphlet 
‘Forsøgspersonens 
rettigheder 
i 
et 
sundhedsvidenskabeligt 
forskningsprojekt’ reviewed and published by the ethical committee system, Sep 2019 
 Information about processing of participants’ personal data and biological material in 
accordance with the European General Data Protection Regulation (GDPR). 
 Power of attorney for joint custody holders for one custody holder to give consent on 
behalf of the other custody holder (Appendix 7).  
Parents (or custody holders) are asked to carefully read all the information material and to 
explain the content to their child/children. The information material will be translated into the 
languages judged by the school and research team to be most relevant for the included 
classes. 
Parents sign up for information meetings at the school, either via a secure online system or by 
handing in a physical “paper-slip” to their teacher. Parents are informed that they must bring 
their child to the information meeting, and that they can also bring an assessor (”bisidder”) if 
they wish.  
Prior to the information meetings, members of the research team will visit the schools in the 
morning during the time slot where children are usually dropped off at school, and/or in the 
afternoon when children are usually picked up or at other times considered relevant by the 
school. The researchers will hand out one-page information leaflets about the study (Appendix 
8), encourage parents to participate in the information meetings, and answer any questions 
from parents about the study. In addition, one-page information leaflets will be handed out 
to parents in the involved classes by staff in the afterschool clubs, and posters about the 
project will be posted at the schools (Appendix 9). Members of the research team may also 
visit the involved classes during school time and inform the children about the study activities 

 
 
 
 
 
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in a language and at a level appropriate for their understanding, cf. Committee Act § 5, stk. 2. 
The parents and children will always be informed that participation is entirely voluntary, and 
that the decision on whether to participate will in no way impact the child’s schooling.   
6.2.5.2 Information meetings for families at the school 
The information meetings will be held at the school in groups of maximum 25 families per 
meeting. Parents will be informed that they must bring their child to the information meeting.  
At the meetings, the background and objectives of the study will be presented by the 
Investigator, or by a qualified person who is delegated to give the information, and the parts 
of the study that involve the family and child will be explained in detail to both the parents 
and the children (see the content of the information meeting in “Table 1. Overview of study 
procedures and activities“).  Also, the parents will be informed that in case of an incidental 
finding concerning their child, e.g. hyperglycemia, or hypertension, they will be contacted 
either by phone or e-mail if it is judged to be clinically relevant by the Clinically Responsible 
Physician. 
In line with the Committee Act § 5, stk. 2, information to the children will be provided in a 
language and at a level that is appropriate and suited for the children’s age and 
comprehension. The information to the children will be provided by project staff experienced 
in communicating to children or who have been trained specifically for this task. There will be 
time and room for asking questions, also in a separate room one-to-one. If the parents or the 
child are unable to participate in the information meetings, they can have the oral information 
for themselves (see below section 6.2.5.4). If the project staff judges that some parents need 
a second explanation of the study, this will be encouraged. It will be emphasized that the 
participants have the right to at least 24 hours consideration time, that participation is 
voluntary, that the participants can withdraw from the study at any time without giving a 
reason and without any consequences, and that all personal data will be kept strictly 
confidential. It will be ensured that parents with insufficient knowledge of Danish will be 
adequately supported to fully understand the information provided.  
The research team will register which parents and children are present at the information 
meetings, and during information provided to children in the classroom, in order to make sure 
that the custody holders and the child have received thorough oral participant information 
and fully understand the study and its procedures. 
6.2.5.3 Informed consent process 
In case the parents/custody holders and the child want the child to participate and do not wish 
further consideration time, both parents/custody holders together with investigator or a 

 
 
 
 
 
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delegated and qualified person fill out the consent form (Appendix 6) at the information 
meeting. They will also be informed that by signing the informed consent they give permission 
for the controlling authorities to access their data, and that a person carrying out these 
functions is subject to the rules of confidentiality. 
In the supplementary information about GDPR, parents and participants will receive 
additional information about the way data and biological material are collected, shared, and 
made available for other researchers and data processors in compliance with GDPR. 
If parents/custody holders or children wish further time for consideration, the 
parents/custody holders will receive an informed consent form to take home. The informed 
consent form must be signed by the parents/custody holders and the investigator or a 
delegated and qualified person, and additional questions from the parents must be answered. 
No study procedures can be initiated before the informed consent is obtained. One parent or 
custody holder can empower the other parent or custody holder to decide whether the child 
should participate (Appendix 7). The parents will also be given the opportunity to sign the 
informed consent form by electronic signature, via a link which will be sent out on Aula or E-
boks immediately after the information meeting only to those who participated in the 
meeting. 
As the study participants are under the age of 18, they cannot give informed consent. 
However, the project staff will be aware of the child’s response and reactions to the study 
(both verbal and non-verbal responses); if the project staff at any time judges that the child 
does not want to participate in the study, the child will not be included. 
6.2.5.4. Parents who do not participate in information meetings 
Follow-up information meetings, either in groups or as individual meetings, online or face-to-
face, will be arranged for parents/custody holders and children who were not able to 
participate in the initial meetings.  
School staff will be asked to encourage families to participate in information meetings to learn 
about the study, but it will always be stressed that participation in the study is completely 
voluntary, and that a decision not to participate will in no way impact their child. We will ask 
school staff (e.g., teachers and pedagogues) to offer parents the possibility to be contacted by 
telephone by a member of the research team, if the parents wish further information about 
the study before deciding whether to participate in one of the information meetings.  

 
 
 
 
 
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6.2.5.5. New students enrolled in the schools during the study period 
If new students are enrolled in the participating school classes during the intervention period, 
they and their parents will be invited to participate in the study. Parents will initially be 
contacted by the schoolteacher via Aula or in person. If they are interested in hearing more 
about the study, the parents and children will receive oral and written participant information 
by the research team following the same procedures as described above in section 6.2.5.3. 
Written informed consent will be obtained from custody holders before enrolment into the 
study.   
6.2.5.6 Recruitment of local stakeholders 
In each local intervention community, a stakeholder analysis will be done together with 
representatives from the municipality and school. Potentially relevant stakeholders will 
initially be invited for a bilateral meeting. Relevant stakeholders will initially be defined as 
community leaders who have authority to initiate action within child health and well-being, 
including leaders from the municipality, the local school, local sports- and leisure time 
organizations, and private businesses such as local supermarkets and restaurants. These 
leaders will build a system map of drivers of obesity in the local community as further 
described in section 6.3.1. The system map captures drivers of childhood obesity in the local 
community. Subsequently, a larger group of community representatives will be engaged from 
organizations whose activities and agenda includes remit and capacity to influence children’s 
food and activity environments, screen time and sleep. Furthermore, selected local leaders 
and stakeholders in each community will be invited into a Local Community Partnership Group 
(LCPG) that will function as a steering group during the project period and help ensure 
coordination and long-term local anchoring of the intervention program. 
6.3 Intervention  
6.3.1 Principles of the intervention 
The development of the intervention in the intervention school districts will be guided by the 
Medical Research Council framework on designing complex interventions as well as a systems 
thinking approach (58,74,75). Furthermore, the super-setting approach will guide the process 
of creating synergy between intervention components (76). 
The development of the intervention will take place on three levels: 
a) Core intervention components at school level based on existing evidence  

 
 
 
 
 
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b) Intervention components developed in co-creation with national stakeholders 
c) Community capacity building in each intervention local community 
The core intervention components at school level are pre-defined based on existing evidence 
and will be described in section 6.3.2 Intervention in schools and after school clubs. The 
intervention at school level will be refined based on experiences from the pilot study. 
Furthermore, the intervention components will be adapted to the local context of each school. 
Other interventions will be developed primarily outside school, focusing especially on 
changing the environmental drivers of childhood obesity (social, cultural, physical, economic, 
and political). Inspired by the Public Health England’s publication “Whole systems approach 
to obesity: A guide to support local approaches to promoting a healthy weight” (59), a co-
creation process with national stakeholders took place prior to the pilot study to develop 
relevant interventions. The national stakeholders included representatives from national 
supermarket chains, fast food restaurants, Rådet for Sund Mad [Council for Healthy Food], 
national leisure time organisations, Local Government Denmark (KL), The Danish Healthy 
Cities Network, Danish Health Authority, The Danish Food Administration etc. After the initial 
stakeholder analysis, the process of co-creation consisted of a series of bilateral meetings and 
two workshops. In the first workshop, a systems map was developed using the software 
STICKE (77). In the second workshop, stakeholders came together to prioritise areas to 
intervene in the local system and propose collaborative and aligned actions to bridge 
interventions between settings. The project drew on the expertise and resources of The 
Intersectoral Prevention Laboratory (www.forebyggelseslaboratoriet.dk) who is responsible 
for the process of facilitating the creation of a systems map using STICKE. 
Community capacity building will take place in each of the local intervention communities. 
Initially, a stakeholder analysis will be conducted to identify community leaders and 
stakeholders that have authority to initiate action and that would be relevant to engage in an 
intervention anchored in the local community promoting healthy weight among local children. 
Inspired by the cluster-randomized trial, WHO STOPS (78), the process will consist of the 
phases listed below:   
 Collecting and communicating local data and scientific evidence to raise local 
awareness of childhood obesity and to engage and recruit community leaders.  
 Identifying, inviting, and working with a smaller group of community leaders who 
have authority to initiate action, including leaders from the municipality, the local 
school, local leisure time organisations, and private businesses including local 
supermarkets and restaurants. These leaders will build a causal loop diagram of 
the causes of childhood obesity in their community (79) using STICKE (77).  

 
 
 
 
 
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 Engaging a larger group of community representatives from organizations whose 
activities and agenda includes remit and capacity to influence children’s food and 
activity environments, screen media habits and sleep.  
 Involving the larger group of community representatives in working together to 
design actions to prevent childhood obesity that they can carry out across the 
community, inspired by the causal loop diagram or systems map and informed by 
a prepared evidence brief on obesity prevention, including case studies from 
previous successful interventions.  
 Ongoing data collection and updates of the systems map to enhance 
implementation and diffusion of the selected actions and stimulate new ideas in a 
constructive, capacity-building cycle.  
 Selected local leaders and stakeholders in each local community will be invited into 
a LCPG that will function as a steering group.  
To develop an overall coordinated intervention programme, the different intervention 
components developed at different levels and in different settings will be combined using the 
Super-setting Approach (76). To promote integration and synergy between interventions, 
common themes for all settings (e.g., mental well-being, taste and senses etc.) will run 
throughout the intervention period for 2-3 months each. 
6.3.2 Interventions in schools and after-school clubs 
Prior to initiation of the intervention and measurement schedule (cf. section 6.6.), project staff 
may visit the school classes and explain the study activities to the children during school time 
in their classroom. This will occur at a level appropriate for the children’s age group by project 
staff specifically trained for this task. Children whose parents have not provided informed 
consent to participate in the study will be exempted from this information. 
6.3.2.1 Food and nutrition 
The dietary intervention will be based on the national Danish food-based dietary guidelines 
(40) and the Nordic Nutrition Recommendations (41) and seeks to promote a balanced energy 
intake, increased healthy food intakes, and improving children’s healthy food competences. A 
key focus will be on increasing intakes of wholegrains, fruits, vegetables and legumes, and fish, 
reducing the intake of sugar, and on drinking water. 
The dietary intervention in school will include pre-prepared do-it-yourself cold lunch and 
possibly a midmorning snack, consisting of for example rye bread sandwiches, pasta salad, 
raw vegetables with dip etc. The children will be involved in the table setting and cleaning 
after the meals. We expect that extra time will be needed to be scheduled for eating by the 

 
 
 
 
 
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schools. Lunch will be offered to all children regardless of their participation in the 
measurement schedule and will be free of charge. We will collect information about allergies 
and other dietary considerations from the parents of participating children at enrolment. 
Parents will be informed that the meals cannot accommodate special dietary needs and that 
the menu with full list of ingredients (including allergens) will be posted on a specific website 
one week before, for them to check which parts their child can eat. The teachers/pedagogues 
will help handling allergies in the eating situation as in a normal school day. We will ask the 
teachers to note any allergies in children who wish to have the meals, but who are not 
participating in the measurements. To encourage water consumption, cold-water dispensers 
will be made available if this is feasible and needed at each school, and each child will receive 
a reusable water bottle. 
In addition to this, we will develop fun and engaging hands-on food competence exercises that 
the teachers can use in their teaching to support the children’s knowledge, self-efficacy and 
liking of healthy foods as well as practical skills in food preparation. Examples are sensorics 
taste exercises, vegetable puzzles and following a recipe to cook a simple dish together in the 
school kitchen.  
In the after-school clubs (SFOs), we will work with their existing offers of breakfast and 
afternoon snacks and provide tips and inspiration to encourage the staff to follow the national 
food-based guidelines. Other activities focusing on healthy diet may be arranged in 
collaboration with the SFO, such as afternoon café for parents where children serve healthy 
snacks and/or excursions to local farmers, greengrocers, or fishmongers. 
6.3.2.2 Physical activity 
The amount of moderate and vigorous PA during school time will be increased through three 
approaches: a) 3x45 minutes of organized vigorous PA, b) education of Physical Education (PE) 
teachers and c) improved facilities and structure for PA during recess and in after school clubs. 
a) 3x45 minutes per week of organized vigorous physical activity during school time 
To ensure that all children reach the recommended 3x30 minutes of vigorous activity per 
week, we will implement three weekly 45-minute sessions in the school curriculum. These 
sessions will be carried out throughout the study period and will encompass modified and 
varied sporting activities (80) and games, which promote motivation, active involvement of all 
children, and intensity. These 45-min sessions are developed to promote joy though play, 
provide appropriate challenges of the children’s motor competences and physical capacity 
and, importantly, to achieve at least 30 minutes of varied, vigorous activity in relation to 
cardiopulmonary and musculoskeletal loading for all children, irrespectively of sex, fitness 

 
 
 
 
 
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levels, skills, and prior experience with sporting activities (80). The activities will thus be 
adapted to allow participation for all children. 
b) Physical activity during school recess 
In primary schools, recess time amounts to almost 5 hours weekly and is a setting where young 
school children on average have a high level of PA (81). This makes recess an important part 
of the total daily and weekly amount of MVPA for young school children. It has been shown 
that improved facilities, both in terms of permanent play and sport facilities (e.g., climbing 
frames, football goals) and loose play equipment (balls, skipping ropes, skateboards), 
increases mean daily amount of PA among young school children as well as the proportion 
reaching daily recommended levels of MVPA (82,83). This part of the integrated PA 
intervention centres on distributing packages of loose play and sports equipment to school 
classes and making agreements with schools and teachers about how these are distributed 
and collected at the beginning and end of recess. Previous projects such as Move@School 
have shown this to be feasible and a popular approach for improving children’s opportunities 
to be active during recess. This will be supplemented by the concept of drawing lines in the 
schoolyards for 4-square and similar games and, if relevant, providing small goals for 
basketball, floorball and football.  
c) Physical activity in after-school clubs 
Danish school children at age 7-8 years spend about 10 hours a week in after-school clubs. 
Mean activity level is moderately high, but great variation is seen between children (81). More 
physical activity in this setting will be facilitated by implementing policies limiting computer 
gaming as an activity and facilitating outdoor activities as much as possible.  In collaboration 
with the staff at the after-school clubs, activities suiting the institutional facilities and time 
structures will be developed and the equipment needed will be identified.  
6.3.2.3 Sleep and screen media habits  
During the study period, teachers/pedagogues will be asked to facilitate small assignments on 
screen media and sleep practices with the children during school time. The children will be 
asked to discuss and reflect upon screen media and sleep practices in their family, based on 
material from e.g., Medierådet (The Danish Media Council). The results of the children’s 
assignments will be presented at later workshops for the parents (see below in section 
6.3.3.2). This is done to integrate the children’s perspective in the parent workshops, 
especially in relation to screen media habits.   

 
 
 
 
 
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6.3.2.4 Education of school staff 
School staff (teachers and pedagogues) involved with the 1st and 2nd grade classes at the 
intervention schools will be asked to participate in three courses in the beginning of the study 
period: 
Course on food and nutrition (approx. 4 hours): Teachers and pedagogues involved in 
preparation of the school food and having lunch with the children will receive education and 
material in e.g., the hygienic and pedagogical aspects of food and eating, nutrition, sensorics 
as well as tips and exercises to be used in the classroom.   
Course on PA (6 hours): The aim of the educational program for PE teachers and other 
teachers with responsibility of PA in the class is to develop children’s understanding, 
motivation, and abilities for being active in different sports and exercise activities throughout 
life. In many ways, the aim is to develop children’s physical literacy (PL). We aim to help 
schools and PE teachers fulfil the ambitious aim of PE by offering a short educational program 
developed and tested in the PE component of the Y-path program (84). PE teachers will be 
offered this short education in combination with peer supervision and sparring on how to 
support children’s PL development and how to create a motivating and inclusive climate for 
all.  
Course on children’s screen media and sleep habits (3 hours): Teachers and/or pedagogues 
with overall responsibility for the class will participate in an educational program related to 
children’s sleep and screen media habits. The educational program will inform teachers about 
evidence and recommendations on sleep and screen media habits, and examples of class 
exercises and activities for the workshops will be presented.   
6.3.3 Interventions focused on the child through the family 
The interventions focusing on the child through the family will include fixed intervention 
components determined à priori by the research team, as well as co-created intervention 
components developed in collaboration with families.    
During the intervention period, up to four parent or family workshops will be held at the 
schools each year. The workshops will be used to convey important scientific knowledge 
within each of the project’s focus areas (diet, physical activity, screen media habits and sleep) 
to the parents. The workshops will also include practical exercises, such as inspiration for ways 
that parents can engage in physically active play with their children and/or tips and tricks for 
involving children in daily cooking. Furthermore, the workshops will be used to ask parents to 
provide their views on perceived individual-level and structural barriers for adopting healthier 

 
 
 
 
 
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habits, and in collaboration with parents, we will co-create interventions which could support 
behavioural changes within each focus area. 
The form of each workshop will be decided in collaboration with the school. The workshops 
will be facilitated by members of the research team, teachers, pedagogues and/or external 
experts (such as Medierådet, Børns Vilkår, Hello Kitchen etc.), depending on the content of 
the specific workshop. Participants in the workshops may be parents alone and/or parents 
and children together. 
We will pay special attention to avoid lecturing, parent bashing, stigma, and unhealthy focus 
on body weight. Focus will be on actively engaging and involving parents in promoting 
healthier lives in their family and in the local community. To reach all parents irrespective of 
ethnic and educational background, we will provide simple messages supported by visuals, 
and we will translate material into numerous languages if recommended by the school. 
Written study material, such as invitations for workshops and inspirational material, will be 
sent to parents by e-mail via the software REDCap and/or via AULA and in print via the 
teachers. Inspirational material may include, for example, inspiration for birthday parties and 
playdates including fun physical activities that promote movement as well as suggestions for 
simple, fun and healthy food which we will develop together with the school and/or other 
stakeholders. 
The planned intervention components which involve the families within diet and sleep/screen 
media habits are described in more detail in the following sections. 
6.3.3.1 Diet  
At least one of the parent workshops held at the school during the intervention period will be 
used to provide motivation, tips, and strategies for healthier eating in the family. If feasible, 
there may also be cooking workshops for the families at the school, where families will be 
invited to cook with their children following simple and hands-on recipes to gain practical 
healthy food competences in the families.   
6.3.3.2 Screen media habits and sleep 
Based on the current knowledge of determinants of screen media habits in children, as well 
as our experiences in the family-based ‘SCREENS trial’ (57) and the ongoing school-based 
‘Screen-Free Time with Friends’, the intervention will mainly focus on the interpersonal- and 
institutional (school) level, i.e., the family and peer social networks (85,86).  

 
 
 
 
 
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The overall aim of the screen media habits and sleep intervention component is to promote 
healthy screen media habits, encourage healthy sleep practices in the participating children, 
and to reduce the gap between the parents’ and child’s understanding of digital literacy.  
The intervention will contain fixed generic components such as facilitating class culture and 
providing parents with the latest knowledge and recommendations within sleep hygiene and 
screen media habits. 
Inspiration sheets 
All parents, (also those who have not provided consent on behalf of their child to participate 
in the study), will receive inspiration sheets introducing knowledge and recommendations 
about screen media habits and/or sleep, potential tools to address this knowledge as well as 
suggestions for child and parent activities to support dialogues about sleep and screen media 
habits between the children and parents. Through these inspiration sheets we seek to 
encourage parents to reflect and consider the sleep and screen media habits in their family. 
We will provide parents with tools they can choose to use to support the introduction and 
maintenance of e.g., screen media rules. Importantly, any specific screen media rules will be 
determined by the parents/family and not by the researchers. 
Parent workshops on sleep and screen media habits 
Several parent workshops will be held over the two-year intervention period. The workshops 
will include information and dialogue focusing on children’s sleep and screen media practices. 
The workshops will focus on the assignments on sleep and screen media habits that children 
completed during school hours (see 6.3.2.3). 
The goal of the workshops is to increase parent knowledge on their own and their children’s 
screen media practices, strengthen the dialogue with other parents, their own child, and 
between children within the provided subject (e.g., evening screen media use).  
The topic for the workshops is planned to be an introduction to the knowledgebase for the 
importance of better sleep and balanced screen habits. The meetings will also focus on the 
exchange of experiences (pros and cons) with sleep and screen media habits at home and 
during child playdates among parents and reflections on potential strategies to support better 
sleep and screen media practices among the children during leisure time periods, in the family, 
and to increase the awareness of alternative leisure time activities (e.g., participation in after-
school clubs, sports clubs).  
All parents will be invited to participate in the workshops even though they have not 
consented on behalf of their child to participate in the study.  

 
 
 
 
 
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6.3.4 Intervention focused on the local environment 
6.3.4.1 Local supermarkets, restaurants, and fast-food outlets 
To promote healthier eating, children and families need to be supported within their local 
community by food environments that make the healthy choice the easy choice and not a 
challenge in their everyday life (87–92). 
Within the national partnership established in connection with the study (see section 6.3.1.), 
new solutions will be developed to promote healthier eating among children, e.g., decreasing 
portion sizes, improving the availability of fruit, vegetables, cold fresh water, and healthy 
snacks, and decreasing the availability of sweets and sugar-sweetened beverages in 
supermarkets, restaurants, cafés, fast-food outlets and local sports clubs. Priority will be given 
to increasing the availability of fruit and vegetables, including convenience products, to make 
cooking with vegetables easier. The local community partnership groups (LPCGs) established 
in each intervention school district (see section 6.3.1) will have an important role in adapting 
and anchoring the interventions in the local setting. 
Furthermore, stakeholders from each of the 12 local intervention communities will be invited 
into a co-creation process and to join the LCPGs. Invited stakeholders will be representatives 
from local sports organizations and other leisure time organizations for children, the school, 
the municipality, local supermarkets, restaurants and other private companies, parents, and 
other relevant local actors. The LCPGs will be responsible for developing and implementing 
activities within the local community that can promote healthier environments for children 
and families, including healthier food environment, easier access to active living including 
participation in sporting activities and outdoor activities, community-building activities etc. 
6.3.4.2 Sports organizations 
To support children that are not in sports clubs to join and become members, we will establish 
collaborations between schools, municipalities, and local sports clubs. Such collaborative 
initiatives have been shown to benefit families with low sporting experience, as these families 
are more positive towards sporting activities initiated via the school. 
6.3.5 Compliance 
Adherence to the intervention components will be explored at different levels using multiple 
method e.g., interviews, questionnaires, observations, logs, accelerometry, dietary 
registrations and biomarkers. As part of the evaluation of the implementation, we will assess 
whether the different intervention components are implemented by intervention providers, 

 
 
 
 
 
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e.g., teachers and other pedagogical staff, as intended and to what extent (dose delivered). 
Moreover, we will explore to what degree children and parents are exposed to the 
intervention component (dose received and reach). We will also explore participation in 
general. 
6.4 Control schools 
The control schools will be offered education related to physical activity for the eldest classes 
in the school, and the participating children in the present study will be offered participation 
in an activity day by the end of the study period.  
6.5 Overview of study procedures and activities 
The table below summarizes the activities described above and provides an overview of the 
planned study procedures as well as measurements, which will be conducted in 4 test rounds 
i.e., at the beginning and end of each of the two school years. The measurements will be 
further detailed in section 6.6. 
Table 1. Overview of study procedures and activities 
May 2023 
Initial contact 
 Invitation letters and participant information are distributed to 
parents / custody holders  
May to September 
2023  
Information meetings at the school  
 An understandable presentation of the context and purpose of 
the study  
 An understandable explanation of the study interventions and 
measurements to parents and children.  
 Description of rights and considerations before decision  
 Description 
of 
foreseeable 
risks, 
adverse 
events, 
complications, and inconveniences  
 Unpredictable risks  
 Voluntary participation and right to withdraw at any time  
 Review of pamphlet “Before you decide” (11.NVK marts 2019) 

 
 
 
 
 
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 Information regarding handling of personal data/biological 
material, confidentiality, and general compliance with The 
European 
General 
Data 
Protection 
Regulation/Databeskyttelsesforordningen. 
 That all data collected during the participation in the study will 
be used in the event of a participant chooses to withdraw from 
the study 
 The right to time for reflection  
 Questions  
 Explanation of informed consent and withdrawal  
 Collection of informed consent (including the possibility for 24 
hours of consideration time) 
 Evaluation of inclusions/exclusions criteria including the 
allergy questionnaire  
Staff education 
 Courses at schools – an education program for teachers and 
related staff involved in the intervention (see section 6.3.2.4) 
Preparation of measurements  
 Instructions 
on 
dietary 
recording 
and 
accelerometer 
measurement  
Round 1: August-
November 
2023 
(baseline) 
+ 
Round 2: April-
June 2024  
+  
Round 4:  April-
June 
2025 
(endpoint) 
Measurements at home:  
 Three-day dietary record, app. 30 min/day 
 Accelerometry 
 Screen/app time 
 Questionnaires  
Measurements in school:  
 Fasting blood sample and time for breakfast  
 Height, weight, and waist circumference 
 Body composition (BOD POD and bioimpedance) 
 Blood pressure and heart rate  
 Mounting of accelerometer device   

 
 
 
 
 
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 Cognitive functions and school performance (math and 
reading) 
 Physical and motor function tests (handgrip strength, balance, 
vertical jump, sprint, agility, gross and fine motor function) 
 Yoyo running test 
 Adverse events 
 Questionnaires 
Round 3: August-
November 2024  
(Subset of round 
1,2 and 4) 
Measurements at home: 
 Three-day dietary record, app. 30 min/day 
 Questionnaires  
Measurements in school: 
 Height, weight, and waist circumference 
 Body composition (BOD POD and bioimpedance)  
 Blood pressure and heart rate  
 Physical and motor function tests (handgrip strength, balance, 
vertical jump, sprint, agility, gross and fine motor function) 
 Cognitive functions 
 Yoyo running test 
 Questionnaires and school tests (math and reading) 
October 2023 to 
June 2025  
Activities in school and in the community
 School lunch 4-5 times per week  
 Possibly a midmorning snack 4-5 times per week 
 3x40 minutes of organized vigorous PA per week in school. 
 PA in breaks and after school clubs. 
 Inspiration sheets for families on screen media habits, sleep 
and dietary habits etc.  
 Tips and inspiration for staff in after-school clubs on how to 
follow the national food-based guidelines  
 Cold-water dispensers and reusable water bottles, if relevant  
 Parent workshops at the school 
 Assignments / exercises for children during school time about 
screen media habits, sleep, nutrition and food competences 

 
 
 
 
 
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Other  
 School staff education  
 Packages of loose play and sports equipment for school classes
 Community events 
 Fieldwork, interviews, logbooks, and short questionnaires for 
e.g., parents, school staff and local stakeholders 
 Observations 
 
 
6.6 Measurements and study procedures 
As mentioned, measurements will be conducted in 4 test rounds i.e., at the beginning and end 
of each of the two school years. Each measurement will be conducted in all 4 rounds, unless 
stated otherwise below. 
6.6.1 Questionnaires to be filled in at home  
The questionnaires will be administered via text message and e-mail with a link to the 
electronic survey to parents.  
The following questionnaires will be administered: 
 Family background (round 1 or at round 2, 3, 4 or at new enrolments if not answered 
at previous data collection rounds): Data on children’s SES will be collected from the 
parent(s) or legal guardian(s) using the Danish Occupational Social Class Measurement 
(93) (appendix 10). 
 Sun habits (vitamin D) (in appendix 10) 
 Child’s leisure time sports participation (in appendix 10).  
 Pubertal stage (round 1 and 4) (appendix 11-12). 
 Food allergies, plaster allergies, or chronical disease (Appendix 2a and 2b (control 
schools))  
 Neurodevelopmental disorders and medical conditions (in appendix 2a and 2b) (at 
round 1 or at round 2, 3, 4 or at new enrolments if not answered at previous data 
collection rounds). 

 
 
 
 
 
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 Breakfast consumption, intake of wholegrains, sugary foods, beverages, fish, and 
dietary supplements (appendix 13). 
 Wellbeing & Quality of Life: Children’s well-being will be measured by KIDSCREEN 27 
(parental edition) (appendix 14) (round 1, 2, 3 and 4) (94). As no valid measure exists 
for children under age 11, the parent version will be used to supplement the child 
version.  
 Child and parent screen time, type and current screen time practices (round 1, 2 and 
4) will be collected using the modified parent reported SCREENS questionnaire (95) 
(appendix 15).  
 Child quality of sleep (round 1, 2 and 4) will be measured using the Children’s Sleep 
Habits Questionnaire translated to Danish (96) (appendix 16).   
 Perception of the project and the activities (see section 6.6.4). 
 Adverse events and concomitant medicine (round 2, 3 and 4) (appendix 17). 
 Drop-out questionnaire (at dropout) (appendix 3). 
6.6.2 Other procedures at home 
6.6.2.1 Dietary records 
Children’s daily intake of food and drinks will be recorded by the parents for three consecutive 
days (two weekdays and one weekend day). We will use the validated, web-based tool, 
myfood24, which uses data from the national food composition tables. The tool is user-
friendly, suitable for the target group and recording links can be sent via email.  
6.6.2.2 Screen time and categorized app time measurement  
At baseline, we kindly ask the parents to install a research-based app, Ethica 
(https://ethicadata.com), on the participating child´s own smartphone (if they have one) at 
round 1, 2 and 4 over a period of 14 days collecting information on screen time and 
categorized app usage and screen time patterns. After installation, the app runs automatically 
in the background. The app has been developed to meet legal requirements for data security.  
6.6.2.3 Physical activity and sleep assessments (Axivity)  
At round 1, 2, and 4 detailed, objective information on the whole spectrum of behaviours will 
be assessed by continuous 24-hour/7-8-day Axivity® accelerometer measurement using thigh 
positioned monitors. Using the thigh measurement position the modified age-adjusted 
method of Skotte et al. (97) provides the ability to classify postural allocations like sitting, 
standing and activities like walking and running with high sensitivity and specificity in children 

 
 
 
 
 
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(98). Time lying in bed and sleep time will be objectively measured using an accelerometer 
classification algorithm that is currently under development. 
The Axivity® AX3 monitor is a small (23 x 32.5 x 7.6 mm), lightweight (11 g), waterproof, 3-axis 
accelerometer data logger (Axivity, 2016). The Axivity® AX3 will be attached to the skin using 
thigh belts developed by a Danish company (Elas) or tape (Opsite Flexifix®, Fixumull®) directly 
on the body using compress (gaze) or artificial skin (DuoDerm) between the monitor and the 
skin. We have good experience with both methods attaching the Axivity® AX3 monitor to the 
body, but using plaster is more time consuming so we need to find out which method is most 
feasible in the study. The monitors will be attached at the school. All observers/staff in contact 
with the children will undergo pedagogical and professional training in the tests and in carrying 
out the measurements with the children and in adherence with Danish law have the necessary 
criminal records bureau check. It is important to ensure that the children also give their assent 
to participate in the study, if their parents have provided a written consent allowing them to 
participate. During the study period we will be aware of the children´s reactions and whether 
they feel comfortable or not with the test situations. If the children do not want to wear 
accelerometers, we will respect this. Children with plaster allergy, childhood eczema or 
sensitive skin will always be offered to use belts. The children or parents will receive an 
information leaflet to take home or on the parent email including relevant information 
regarding the physical activity measurement. 
6.6.3 Measurements in school 
Two program centres (UCPH and SDU), with specially trained test teams, will be responsible 
for the measurements in the schools. 
6.6.3.1 Measures of anthropometry including height, weight, and waist circumference 
The children will be weighed once in underwear/light clothes on a digital scale. Standing 
height will be measured three times to the nearest millimetre with a stadiometer. Waist 
circumference will be measured three times to the nearest millimetre by a non-elastic 
measuring tape at the level of the umbilicus. The mean of three measurements will be used 
for height and waist circumference. 
6.6.3.2 Body composition and blood pressure 
Body composition (i.e., FM and fat free mass) will be measured by air-displacement 
plethysmography using a BOD POD and a bioimpedance weight (InBody 270). The children will 
be wearing underwear/light clothes and a bathing cap. The children must sit in a transparent 
capsule for approximately 5 minutes (BOD POD), the bioimpedance measures takes 
approximately 1 min.  

 
 
 
 
 
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Blood pressure and resting heart rate will be measured three times by an automated device 
while the child is lying down after 10 minutes of rest. The appropriate cuff size for the child’s 
arm circumference will be used.  
6.6.3.3 Blood samples 
At test round 1, 2 and 4 blood samples will be collected in the overnight fasted state (except 
water) in the children. The children can have breakfast shortly after. We will instruct the 
parents to provide the children with a breakfast pack on the measurement day but will also 
have food available for children that do not have any. The children will be provided with local 
anaesthetic patches (EMLA), which the parents will be instructed to apply on the child’s arms 
in the morning (appendix 18). After removal of the patches, max. 30 ml blood will be drawn 
from the child’s forearm by trained laboratory technicians. The blood samples will be brought 
back to University of Copenhagen or University of Southern Denmark for processing and 
storage at –70oC until analysis.  
6.6.3.4 Health related fitness and motor functions  
Aerobic fitness and intermittent exercise performance will be evaluated by the Yo-Yo 
Intermittent Recovery Level 1 Children’s test (80), where the children will have to run 2x16m 
at increasing speed with 10 s break between each run. The test continues until the children 
cannot reach the finish line in time and takes around 20 min. for up to 50 pupils, depending 
on the size of the indoor gym. Heart rate will be measured continuously during the test, to 
determine endurance capacity and maximal heart rate. The test is simple and validated for 
fitness and maximal heart rate assessment for 6-10-year-old children (99). Heart rate and 
locomotor activities will also be measured during selected physical activities throughout the 
study period to describe the intensity. 
Muscular fitness, strength and sprint performance will be determined by the hand grip 
strength test and a 20-m sprint test. The hand grip strength test is conducted with a hand grip 
Dynamometer. The child squeezes the dynamometer with all their strength, two times with 
each hand. An average score is then calculated using the measurements from both hands. 
Sprint time is measured by photocells. The children will complete each test twice and will be 
instructed to use all their power.  
Gross motor functions are assessed as static and dynamic balance ability, upper extremity 
gross-motor function, jump height and agility. Jump height and balance ability are measured 
on a force plate measuring the vertical ground reaction force. Jump height is measured during 
the vertical countermovement jump test. Balance ability is measured during one-leg 
maintained balance and as maximum reaching ability during maintained balance, Agility is 

 
 
 
 
 
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measured as time to complete an agility running exercise preferably as a T-drill. Time to 
completion is measured by photocells. The children will complete each test twice and will be 
instructed to use all their power. Upper extremity gross-motor function is tested as speed and 
accuracy in the ability to perform accurate, goal-directed reaching movements towards a 
number of visually displayed targets within 30s or 1 minute. Fine motor function is measured 
by completion of a pegboard test where the children use both the dominant and nondominant 
hand to manually place small rods in the pegboard within 30s or 1 minute (100). 
6.6.3.5 Test of cognitive functions and school performance 
At test round 1, 2 and 4 the children will complete a short battery of standardized, validated 
and age-appropriate neurocognitive tests (100,101) including tests of executive function, 
memory, and attention. The tests resemble computer games, and they are administered 
individually via a tablet or iPad.  At these time points, school performance will also be assessed 
by use of standard and age-appropriate tests of Danish spelling, reading and mathematics 
proficiency (100,102). We have good experience administering these methods in a school 
setting and for children at this age. 
6.6.3.6 Wellbeing & Quality of Life: KIDSCREEN 27  
Children’s well-being will be measured using KIDSCREEN 27 (appendix 14). This validated 
questionnaire consists of 27 items that measure five dimensions of children’s quality of life 
and well-being. These are physical well-being, psychological well-being, relationship with 
parents, relations to peers & social support, and life quality in the school environment (94). 
Due to the respondents’ low age and inability to read a video and speech assisted child version 
of these questionnaires will be developed. The children will fill in this questionnaire using 
tablets and headphones enabling all items of the questionnaire to be read aloud, while the 
text appears on the screen. The answer scale points are illustrated with smileys.  
To assess pupils’ psychological well-being and functioning during school-based intervention 
activities, basic psychological needs satisfaction and intrinsic motivation is measured acutely 
right after occurrences of the school intervention activities. Satisfaction of children’s three 
basic psychological needs for experiencing relatedness; - competence and autonomy as well 
as intrinsic motivation - will be measured with 3 items each adapted from Basic Psychological 
Needs Scale (BPNS-R) for PE (103) and the Intrinsic Motivation Inventory (104,105) adapted 
to the age-group and context (Appendix 18). A smiley based 4-point answer scale will be used. 
To assess the motivational climate during intervention activities, systematic observations and 
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support) dis-empowering climate (ego-orientation and controlling behaviour) will be collected 
during intervention activities.  
6.6.3.7 Motivation, confidence, and knowledge in relation to physical activity  
A Danish version of the Canadian Assessment of Physical Literacy (CAPL) questionnaire, 
validated and context adapted in the Danish Assessment of Physical Literacy (DAPL) study 
(106), will be used to measure children’s intrinsic motivation and confidence for physical 
activity as well as their knowledge and understanding of physical activity. A Danish video and 
speech assisted child version of these questionnaires has been developed and validated in the 
DAPL study (school grade 1 to 6). The children will fill in this questionnaire using tablets and 
headphones enabling all items of the questionnaire to be read aloud, while the text appears 
on 
the 
screen, 
will 
fill 
out 
this 
questionnaire 
(see: 
https://www.survey-
xact.dk/LinkCollector?key=PHC22ZQNUJ9K or Appendix 19). 
The children will also be asked about their participation in leisure time sports club activities 
(Appendix 20).   
6.6.3.8 Food competences and meal culture 
Children’s food competence and meal culture will be assessed using a self-constructed 
questionnaire developed for and validated in the age group (Appendix 21). 
6.6.3.9 Registration of snack and lunch consumption 
On selected days, portion sizes and food/beverage intake at breakfast, midmorning snack, 
lunch and afternoon snack in schools/after school clubs will be recorded at class level in a 
subsample of the schools. Also, teachers/pedagogical staff present in the classes during the 
children’s consumption of midmorning snack (if provided by the project) and lunch will be 
asked to roughly assess and register the intake of each of these meals at class level.  
6.6.4 Evaluation of measures related to implementation of the intervention and 
organizational aspects 
To explore acceptability, perceived outcomes, and consequences of the intervention, as well 
as structural and organizational aspects related to implementation of the intervention, school 
management at each school, and/or other relevant personnel with coordinating/managerial 
responsibilities related to this project, will be asked to complete a questionnaire and to 
participate in interviews. Moreover, all teachers and/or other relevant pedagogical staff, 
affiliated with the various intervention components, will be asked to complete a survey and 

 
 
 
 
 
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to participate in group interviews. Field work during school hours, e.g., classes, PA sessions, 
recess, and lunch with focus on how the intervention unfolds in practice, reasons for 
adaptation, and participant responsiveness will be conducted via observation methods etc. 
Parents will be asked to participate in a focus group interview and to complete a questionnaire 
regarding perception of the project and the activities. Moreover, PE teachers are asked to 
roughly assess and register attendance and active participation during the 3x45 minutes 
sessions of PA at class level. Local coordinators will be asked to register the number of parents 
who attend school events, to explore implementation and perceived outcomes of the 
intervention. Moreover, fieldwork will be conducted when possible. 
To explore relevant structural and organizational aspects as well as initiatives focusing on diet, 
physical activity, screen time and/or sleep in the control schools, the school management at 
each control school will be asked to complete a (few) questionnaire(s) and participate in an 
interview. 
6.6.5 Measurements at further school, community, and national level 
During the study, we will track the implementation and stakeholder engagement. 
Implementation data will include a register of activities in each local community, a database 
of stakeholder engagement and key engagement activities. Data will be collected on a regular 
basis and use methods recently described by Maitland et al. (107).  
Furthermore, we will collect structural data on food environments, including accessibility and 
spatial layout of stores, using digital maps, GIS data (e.g., Smiley register) and field studies 
(90). 
We plan to conduct both a) interviews with the manager of the after-school club and 
facilitators of activities in the leisure time clubs and the active summer holiday camp as well 
as b) systematic observations on selected days to explore acceptability, perceived outcomes 
and consequences of these intervention components. Moreover, we expect that actors 
involved in the implementation of intervention activities, e.g., schoolboard members, 
managers of after-school club, volunteers in leisure time clubs, will be asked to fill out 
questionnaires and/or take part in interviews exploring structural and organizational factors 
influencing implementation. Several core theories, models and frameworks within 
implementation science will serve as reference points for the mentioned investigations. 
We will measure local and national partnerships using the Danish translation of the VicHealth 
partnerships analysis tool (108). Furthermore, this tool will be adjusted and adapted to the 
current project inspired by the work done by Indig et al. (109).  

 
 
 
 
 
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6.6.6 Use of the school’s recordings of children’s absence 
As an indicator-measure of intervention effects on the children’s general health and school 
wellbeing, we will seek to obtain the schools’ recordings of children’s attendance and absence, 
by parental consent. 
6.7 Adverse Events 
Adverse events (AEs) will be registered during the intervention. At each round of 
measurements, parents/custody holders will be asked by questionnaire if their child has had 
any AEs or reactions and any new medicine or changes in dosage taken since the last 
measurement as well as the start and end date (Appendix 17).  In addition, parents will be 
asked to contact us if any events or reactions occur. The medically responsible physician will 
evaluate and record the intensity, causality, actions needed and outcomes of reported events.  
6.8 Handling of biological samples   
6.8.1 Sample analysis 
Biological samples will mainly be analysed at University of Copenhagen, Denmark. Samples 
could also be analysed at other laboratories within and outside the EU, when this is judged 
necessary for the quality of the analyses. Therefore, it is not possible for researchers to predict 
in advance where analyses will be carried out and by whom. If data is transferred to countries 
outside EU to a country which cannot ensure an adequate level of protection, the transfer will 
be in accordance with chapter V of the GDPR. Parents will be informed that their data may be 
sent to data processors in a country like these if this is necessary for the quality of the overall 
result of the study. They are also informed that their data will be sent as 
pseudonymised/coded data and that the transfer will comply with the GDPR.   
Parents will be informed separately about the handling of the data and all data transferring 
will be in accordance with GDPR.  
The processing of data and biological samples in the project and at external data processors 
will be recorded at the mandatory lists to the Danish Data Protection Agency, and all data 
processing will follow GDPR/Databeskyttelsesforordningen and Databeskyttelsesloven. Data 
set and samples will always only be sent to data processors in coded s without any 
accompanying data that could potentially identify the participants.   

 
 
 
 
 
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Table 2 gives an overview of the planned analyses of the biological samples.  
Table 2. Biological sample analyses – blood   
Biomarker field
Analyses 
Compliance 
& 
nutrition 
biomarkers  
 Fatty acids, lipids and other nutrient biomarkers  
 Alkylresorcinols (wholegrains) and other food biomarkers  
 25-hydroxyvitamin D, vitamin D binding proteins and -
metabolites   
 Haemoglobin, ferritin, and transferrin receptor (iron)  
Growth 
& 
development 
 IGF-I, IGFBP-3 and other growth factors 
 Osteocalcin, bone specific alkaline phosphatase and other 
bone markers  
 Parathyroid hormone 
 Sex hormones 
Cardiometabolic
 Triacylglycerol and total, LDL and HDL cholesterol and others 
 Glucose, insulin, C-peptide, glycosylated hemoglobin (HbA1c) 
etc. 
Appetite
 Appetite hormones 
Inflammation 
 C-reactive protein, cytokines, adipokines, and related markers 
  Immune cells and immune markers 
Cognition 
 Blood markers related to brain function such as brain-derived 
neurotrophic factor (BDNF) and serotonin  
Mechanisms
 Metabolomics, proteomics and lipidomics 
 Short chain fatty acids and other metabolites 
Genetics 
 Genotypes and epigenetics related to the study outcomes and 
research questions (single nucleotides polymorphisms and 
genome wide association studies, NOT full genome 
sequencing, and epigenetics) 
 

 
 
 
 
 
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6.8.2 Genotypes and epigenetic analyses 
Gene polymorhisms and epigenetic analyses will be used to investigate biological mechanisms 
and effect modifications, as described in section 5.2.2. We will only investigate genes related 
to the exposure variables and study outcomes, e.g. involved in nutrient status, growth and 
body weight, metabolism, cognitive function etc. Genotyping will not include any full genome 
or exome sequencing, but will either be performed by DNA microarray (such as the Illumina 
Infinium HumanCoreExome Beadchip), that gives information on common gene variants 
(>5%), or by targeted analysis of common single nucleotide polymorphisms. It is therefore 
considered highly unlikely that we will identify any genetic variants that have any direct 
relevance for illnesses. 
6.8.3 Research Biobank 
In relation to the planned analyses in this study a research biobank will be created at 
Department of Nutrition, Exercise and Sports, University of Copenhagen, at Department of 
Sports Science and Clinical Biomechanics, University of Southern Denmark and at the Odense 
University Hospital for storage of blood samples. The research biobank will include maximum 
3 x 30 mL = 90 mL of blood from each child. 
The research biobank is registered at University of Copenhagen and University of Southern 
Denmark, which have shared data responsibility in the project and record all data responsible 
and data handlers, as well as their handling of biological material and other personal data. 
Biological material will be stored at maximum -70 C in the research biobank until analysis is 
completed and will be destroyed no later than 10 years after last participant last visit (June 
2035), unless custody holders have signed a separate consent form that eventual remains can 
be transferred to a biobank (see 6.7.3).  
All personal data/biological material is handled with confidentiality and stored in accordance 
with applicable law, GDPR and Danish Data Protection Act. no. 502 of 23rd May 2018. 
6.8.4 Biobank for future research purposes 
Eventual remains of material of blood (maximum 3x 10 mL=30 mL) from the research biobank, 
will, if the custody holders of participants have signed a separate consent form for this, be 
transferred from the Research Biobanks at University of Southern Denmark and University of 
Copenhagen to a biobank at University of Copenhagen. The biobank material will be stored at 
maximum -70 C at the Department of Nutrition, Exercise and Sports, University of 
Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C. The biological samples in this biobank 

 
 
 
 
 
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will be stored for a maximum of 15 years after last participant last vist (June 2040) and will 
only be used in new research projects after these have been approved by the Danish Regional 
Committee on Biomedical Research Ethics, unless the samples have been totally anonymized. 
This means that the ID-log that connects study participants and the ID on the biological 
material has been destroyed and it is no more possible to identify the participant. If the study 
participants or custody holders of participants choose to donate remains of biological material 
from the research biobank to the biobank and later regret it, they can contact NEXS and have 
the samples destroyed if the samples have not been anonymized.  
PI knows that establishment of a biobank for future related research projects of the excess 
material from the research biobank is not covered by the committee by law, but by the 
General Data Protection Regulation (Databeskyttelsesloven/ Databeskyttelsesforordningen). 
As the procedure is considered relevant for the entire research protocol in Denmark and to be 
able to prove that the biobank is established on a legal basis, the information is included in 
the material for the ethical committee. 
6.9 Data Management and Quality Control 
6.9.1 Data Collection and Processing 
All collected data will be stored in accordance with the General Data Protection 
Regulation/Databeskyttelsesforordningen for data handling. 
6.9.1.1 Data storage in REDCap 
Data from questionnaires and most outcome data collected during school measurement days 
will be collected and stored directly in REDCap, which is a secure platform for building and 
managing online surveys and databases. REDCap is managed by the researcher service 
organization OPEN in the Region of Southern Denmark.  
Research personnel will collect and enter data following formulated standard operating 
procedures. Data quality will be ensured using tailored validation fields in REDCap. 
6.9.1.2 Data storage on other platforms 
Outcome data (smartphone use, cognitive tests and dietary record) will also be stored on 
online servers provided by external companies (Ethicadata, Cambridge Cognition, MyFood24). 
We will establish data handling agreements with the companies to ensure that data is securely 
and not used for other purposes. 

 
 
 
 
 
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Data from heart rate monitors (collected during the fitness test) will be extracted and stored 
pseudonymised in safe folders on university servers at SDU or UCPH. 
Accelerometers will be collected at the schools (after 7-10 days) and transported back to the 
University of Southern Denmark or University of Copenhagen where data will be extracted 
from the measurement devices and stored in safe folders on the University servers. 
Collected blood samples will each day be transported back to the University of Southern 
Denmark or University of Copenhagen where they will be processed and stored at maximum 
–70 degrees Celsius until analysis.  
Process data such as field notes, observations, logbooks, and interviews, which will be 
collected in paper form or recorded, will be entered and stored in safe folders on university 
and/or region servers at SDU and/or Center for Clinical Research and Prevention. 
Aggregated datasets from all data storage platforms other than REDCap will be stored in the 
REDCap file repository. The aggregated datasets will be uploaded to the REDCap file repository 
and include the ID log variable to allow for combination of the datasets. 
6.9.2 Confidentiality 
To maintain confidentiality, participants will only be identified by their initials and an assigned 
participant number. Documents that identify the participant (such as the signed informed 
consent document and the ID log) will be maintained in strict confidence by the investigator, 
except to the extent necessary to allow auditing and/or monitoring by the appropriate 
regulatory authority. All information obtained during the study will be handled according to 
local regulations and the GDPR/Databeskyttelsesforordningen. The study is registered on a 
central list at the Institutions/UCPH and SDU. The universities conduct lists of all data 
controllers/data processors and their handling of the personal data, and the lists are available 
in case of inspections from the Danish Data Protection Agency. 
6.9.3 Information/data from patient hospital records 
Data and information from the participants’ Hospital medical records will not be included in 
this project. 
6.10 Use of data from Danish registers 
We will obtain information on eligible children and their families from Danish registries with 
the purposes to 1) obtain contact information (name, address, and CPR-number) on eligible 

 
 
 
 
 
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children and their parents (for distribution of all participant materials  related to the study), 
2) compare socio-demographic characteristics (parent education and employment) of 
participants with eligible non-participants to better judge generalizability and explore this 
analytically, 3) investigate the long-term (i.e., a 7-year follow-up) effectiveness of the program 
on body composition, and 4) lower the burden of the parental survey with respect to 
sociodemographic information, and 5) limit missing information on sociodemographic 
information due to survey non-response. Registries that will be used for these purposes 
include at least the following: The Civil Registration System (Det Centrale Personregister), The 
National Child Health Register (Børnedatabasen), and the DREAM database.  
In the participant information (Appendix 5a and 5b), we inform all parents that we plan to 
collect information on the above-mentioned factors from Danish registers on all eligible 
children regardless of whether consent to participation in this project has been obtained or 
not. The Legal authority for said collection of data will be Section 10 in Databeskyttelsesloven 
and Article 6 (1) (e) of General Data Protection Regulation  
Furthermore, we will obtain information from Danish national health registers and clinical 
databases, e.g., the National Patient Register, the National Prescription Register, the National 
Health Services Register, the Danish Psychiatric Central Register, the Medical Birth Register, 
and the National Child Health Register, to study associations between lifestyle factors and 
biomarkers collected in the study and subsequent long-term health and morbidity among 
participants. Such registry linkages will be performed for up to 10 years after last participant 
last visit (June 2035) to be able to passively follow the cohort during adolescence and 
adulthood, and thereby study early childhood determinants of later health and morbidity. All 
registry linkages will be performed on secure servers at Statistics Denmark or the National 
Board of Health Data, and all data sets will be pseudonymized before analysis. 
The establishment of a database containing data from this project as well as the subsequent 
transfer of data for related future research projects are not covered by the Danish Committee 
Act. Rather, for said actions, PI must comply with the General Data Protection Regulation 
(Databeskyttelsesforordningen) and Databeskyttelsesloven.  Accordingly, the parents must be 
informed separately about this in the mandatory GDPR information sheet and a valid consent 
must be obtained.     
6.11 Statistical methods  
6.11.1 Primary analyses 

 
 
 
 
 
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All analyses of the predefined primary and secondary outcomes will be planned a priori and 
made publicly available in statistical analyses plans at clinicaltrials.org. Reporting of the trial 
will be done in accordance with the CONSORT guidelines for cluster randomized trials. The 
primary analysis will be conducted on an intention-to-treat basis using mixed regression 
analysis with school district as random effect using degrees-of-freedom correction 
(Satterthwaite) to control for type 1 error due to the moderate number of clusters. Because 
the school district is the unit of randomization (not municipality, region, or school-class) and 
the intervention is being applied at this level, no further cluster-level will need to be 
considered statistically. Analyses will be adjusted for baseline factors that are found to be 
related to individual school districts (clusters) to control for possible baseline imbalance of 
cluster- and participant level data. In analyses using more than two assessment points, 
random slope effects of time will be considered to examine the possible heterogeneity of 
effects according follow-up time. In all intention-to-treat analyses, data from all participating 
children at inclusion will be included. All hypotheses testing will be based on two-sided tests 
at the alpha=0.05 level. 
6.11.2 Secondary analyses 
Analysis and reporting of predefined secondary outcomes will be mentioned explicitly as 
secondary outcome analyses in the papers.  
In addition, several sub-group analyses will be predefined and outlined in the final statistical 
analysis plan before the start of the trial. This will include subgroup analyses by e.g., parent 
socio-economic status, school district characteristics, and baseline adiposity status (being 
normal weight at baseline vs. being overweight or obese at baseline). Sub-group analysis 
among normal weight children at baseline will also be used to examine the effectiveness of 
the program on incidence of overweight or obesity. Other outcomes or sub-group analysis 
that are not predefined in the final study statistical analyses plan published before the start 
of the trial, will be defined explicitly as exploratory post hoc analyses in the papers and the 
exploratory nature of these analyses will be mentioned as a major limitation. Per-protocol and 
complete case analyses of the primary and secondary outcomes will also be carried out. We 
will analyze the association between implementation fidelity and actual dose delivered of 
each intervention activity in each intervention setting and its association with intervention 
outcomes among children. 
In the final statistical analyses plan, a detailed plan to adjust for multiplicity based on a priority 
of the secondary outcomes and follow-up time points will be outlined. 
6.11.3 Exploratory analyses 

 
 
 
 
 
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All analyses that were not pre-planned will be labelled as exploratory analyses.  
6.11.4 Safety analysis 
A safety analysis will be carried out to summarize any reported adverse events associated with 
participation in the study. 
6.11.5 Definition of datasets 
Quantitative datasets will be generated from the REDCap databases for each specific research 
aim guided by a predefined analysis plan. When registry data are needed for analyses, and 
these cannot be stored locally in REDCap, data stored in REDCap will be uploaded to 
‘Forskermaskinen’ at Statistics Denmark. 
6.11.6 Handling of missing values 
Missing values will be handled via the mixed regression modelling approach to analyses 
(110,111).  If alternative analyses are carried out missing values will be imputed using multiple 
imputation or inverse-probability weighting.   
6.12 Suspension or early termination of the study  
The principal investigator may suspend or prematurely terminate parts of or the entire clinical 
study for significant and documented reasons. If a suspicion relating to an unacceptable risk 
to study participants arises during the study, the principal investigator will suspend the study 
while the risk is assessed. The principal investigator will terminate the study if an unacceptable 
risk is confirmed. The principal investigator must ensure that the premature termination is 
justified in writing (fill out the termination form) and that the parents of the participants are 
informed. 
6.13 Serious adverse events and reporting 
6.13.1 Serious adverse events 
A serious adverse event is defined as any untoward medical occurrence in a study participant 
that: 
 Results in death 
 Is life-threatening at the time of the event 

 
 
 
 
 
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 Requires inpatient hospitalization 
 Results in persistent or significant disability or incapacity. 
6.13.2 Reporting of Serious adverse events 
The principal investigator will immediately inform the ethics committees if a serious adverse 
event occurs during the project. Reporting will take place no later than 7 days after the 
principal investigator became aware of any such adverse event. The standard forms from the 
ethics committees will be used for this purpose. In case of serious adverse events resulting 
from the project, the investigator will make any information requested by the committee 
available.  
When the study ends, the principal investigator will provide a list of all serious expected and 
unexpected adverse reactions and all serious adverse events that have occurred during the 
study period. The report will be accompanied by an assessment of the participants' safety. The 
report will be delivered using the forms prepared by the committee system. 
6.14 Study Documentation 
6.14.1 Publication of Results 
Results from the study, whether positive, negative, or inconclusive, will be summarized and 
published in peer-reviewed scientific journals and/or as part of scientific conferences. 
Authorship of publications should in agreement with the publication approval procedure 
reflect the collaborative nature of the project. 
The project is registered in www.clinicaltrials.gov 
7 Ethical conducts of the study 
The study will be conducted in accordance with the ethical principles set forth in the current 
version of the Declaration of Helsinki. Children in the participation classes that are not enrolled 
in the study will be invited to participate in all activities that are like what could happen during 
the school day anyway, but without any examinations and data registration. 

 
 
 
 
 
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It always, and especially for families with small and younger children, interferes with everyday 
life to participate in a clinical study as it requires time to be set aside to comply with the 
procedures of the study, and some procedures may be associated with a risk. 
7.1 Ethical approval and study registration 
Ethical approval is obtained by (Project ID xxxxxx-22 S-xxxxxxxx) and the data processing of 
the participants’ personal data and biological material and the study is registered on statutory 
lists before enrolment of any study participants. 
7.2 Justification of the study 
Investigation of the effectiveness of a health promotion intervention program in children on 
health outcomes is not possible to conduct with high validity in a non-randomized experiment 
or in an observational study. Thus, for the present study there is a need for a control group 
and to investigate the aims of the study using an experimental randomized study design. The 
study will provide important new knowledge about the effectiveness of the Generation 
Healthy Kids program, a novel multicomponent intervention developed using a systems 
approach that can benefit children in Denmark and elsewhere in the future.  
7.3 Underage study participants - justification and precautions 
Justification of inclusion of children in the clinical study is in line with the Committee act 
(Komitéloven §19, stk. 3) which concerns studies not involving medicine, as the project can 
only be conducted in the described age group to answer the objective stated in section 5. 
Further, it is justified to recruit children of this young age as the overall project and main trial 
is focused on early prevention of overweight at school start before the overweight prevalence 
starts to rise markedly. Also, as described below, the study gives minimal risk of harm for the 
participants, and it is our assessment that the benefits outweigh the potential harms. 
7.4 Children of ethnic minority 
All children in the participating classes are eligible for the study. Written information materials 
will be translated depending on what is needed in the local school district. Verbal information 
will as standard be in Danish, but interpreters will be present at meetings if needed.  

 
 
 
 
 
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7.5 Risks and safety in relation to conducting the study 
The interventions will not include focus on weight, but instead promote well-being, healthy 
habits, sense of community, and play. All communication will be prepared carefully in terms 
of non-stigmatization of children or families and there will not be any focus on weight related 
issues. 
Participation in the study is associated with minimal risks.  We have thoroughly considered 
the ethical aspects of the discomfort of the biological sampling. Since the blood samples are 
crucial for investigating the outcomes of the study (including diet and health related 
biomarkers), the discomfort of the blood sample is considered to be outweighed by its 
usefulness. The discomfort of blood sampling will be minimized by use of local anaesthetic 
patches before blood sampling and blood will be sampled by skilled laboratory technicians or 
other trained and qualified staff. The only expected risk of the biological sampling is a mild 
pain at the site of the blood sampling on the arm and potentially a small blue bruise at the site 
of the prick, which will disappear within a few days. Risks for infections that are associated 
with blood sampling are extremely low.  
The children will be asked to meet for the visits after an overnight fast to standardize the blood 
results. They have time to eat immediately after the blood sample, at 10:30 am the latest, and, 
as in our previous trials with blood sampling in children they are allowed to drink 100-200 ml 
during the fasting period and up to 1-2 hours before the blood sampling. A fasting period of 
this duration is relatively short, and we do not expect the children to experience considerable 
discomfort due to the fasting. However, if this should be the case, the examinations will be 
discontinued immediately, and the child will be offered drinks and food. 
The BOD POD body composition measurement is crucial for investigating the primary outcome 
of the main trial (fat mass). The measurement uses air-displacement plethysmography, is safe 
and approved for children, and takes few minutes. The measurement is constantly monitored 
by the operator and if the child expresses discomfort sitting inside the BOD POD, the 
measurement will be stopped immediately. 
There is a risk of more focus on weight related issues e.g., overweight when measuring height, 
weight, and waist circumference. Therefore, the personnel will be trained to talk carefully 
about the measurement and to handle comments on body weight related issues from peers. 
Moreover, the children will not be told the measurement numbers (numbers on digital scale 
is hidden) and they can wear light clothing during the examinations. 
There are no considerable risks related to the school meals which are prepared using foods 
that are part of a normal diet. The parents will be asked about food allergies at project start-

 
 
 
 
 
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up and will be informed to check the menu plans with ingredients allergens online the week 
before. The children will be instructed in hygiene e.g., hand washing. The risk of injury or 
discomfort of performing the muscular and fitness tests are comparable to the risk children 
are exposed to during daily life and play. In case of any discomfort or accident the activity will 
be discontinued. 
The risk or side effect of participating in the measurement of physical activity based on our 
extensive experience in carrying out physical activity measurement in paediatric populations 
is minimal. However, attaching the monitor to the skin on the thigh, might be unpleasant for 
some children and might in some rare cases result in skin irritation or an allergic reaction to 
the adhesive tape. The parents and the child will receive written and oral instruction about 
the instruments, and how the instrument can be removed gently. Furthermore, the written 
information will contain information on which symptoms to be aware of to reduce any 
physical inconveniences in case of an allergic reaction, and whom to contact in case of an 
allergic reaction. If the children participating in this project are allergic to adhesive tape, have 
eczema or other skin problems (se appendix 56), they will be offered to wear a monitor in a 
thigh belt. The belts include skin friendly silicone to keep the belt in place during the child´s 
play. Children/parents can switch the belt between the right and left leg if necessary and to 
avoid/reduce potential skin irritation. 
7.6 Benefits of the study and risk-benefit evaluation 
The overall aim of Generation Healthy Kids is to promote healthy weight and wellbeing in 
children and is expected to benefit future generations of children. Furthermore, it is expected 
that the study will generate new and important knowledge on how to promote sustainable 
changes and potentially how to scale-up.  
The participation in a study can cause some inconvenience to daily life and can be time-
consuming. During the study, the families in the intervention school districts will receive 
school meals for the children, inspiration, and support for healthier lifestyle habits, and the 
control schools will be invited to an activity day by the end of the study period. After 
completion of the study all children receive a diploma (Appendix 22) and after data analysis, 
and publication of the main scientific papers, the parents can read about the study's main 
conclusions on the project's website. 
The schools and local communities are also expected to benefit from the study in terms of 
elevated knowledge and focus on a healthy lifestyle. 

 
 
 
 
 
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All things considered, the study is judged to be ethically justified and proper as the individual, 
scientific and societal benefits are believed to outweigh the limited discomfort and very low 
risk of harm associated with the study. 
7.7 Participant Information and Informed Consent 
Written, informed consent will be obtained from all parents/guardians to the subjects prior to 
entry into the study and execution of any study-related procedures. PI or delegated and 
qualified persons staff will explain verbally to parents/guards the objectives, nature, 
significance, risks, and implications of the study before inclusion. This information will also be 
included in the written subject information sheet. The information will be given at meetings 
at each school. If the parents/guards are not able to join the meeting, they can arrange a 
separate meeting with project staff.  
The parents/guardians will be offered to bring with them an assessor to the information 
meeting and after the meeting they are given time to discuss any questions and decide on 
participation in the study. All parents/guardians will receive a copy of the subject information 
sheet. The children will be informed of the objectives and procedures of tests in a language 
they can understand. The procedures are explained in more detail in section 6.2.5 and in the 
participant information. 
7.8 Protocol Changes 
Substantial amendments to this protocol may be implemented only after a favourable opinion 
of the Ethics Committees has been obtained. Amendments to the protocol are regarded as 
substantial if they have a significant impact on: 
 The safety, physical health, and mental integrity of the study subjects 
 The scientific value of the study 
 The conduct or the management of the study 
7.9 Protocol Deviations 
No systematic deviations from the protocol are allowed. All significant protocol deviations 
noted during the study (by the Investigator) will be recorded in the e-CRF (REDCap).  

 
 
 
 
 
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7.9 Insurance 
The participants are insured in accordance with the Law: “Lov om arbejdsskadeforsikring” (cf.  
LBK nr 1186 af 19/08/2022) by the current insurance at University of Southern Denmark and 
University of Copenhagen. During the study the participants will be covered by law: “Lov om 
klage- og erstatningsadgang inden for sundhedsvæsenet” (cf. LBK no. 995 14/06/2018 
www.retsinformation.dk). 
8 Funding 
The initial concept of the Generation Healthy Kids was developed by the Investigators of the 
study. Generation Healthy Kids is funded by the Novo Nordisk Foundation with 80 mio. DKK in 
total, covering both the pilot study and the main trial.  The study funds have been transferred 
to a research account at University of Copenhagen, which is subject to public audit. The 
funding will primarily cover salary for project staff (PhD students, postdocs, medical laboratory 
technicians, project managers and communication staff) and expenses related to operation 
e.g., school food, buy out of teachers, measurement equipment, analysis of blood samples, 
car rent, measuring instrument (one Bod Pod) and communication materials. Funding will not 
be used for paying subjects.  
The Investigators declare to have no financial interests in the results of the study or any 
economic affiliation with any of the project partners. 
 

 
 
 
 
 
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10 List of Appendices (all in Danish) 
Appendix 1: Protokol resumé   
Appendix 2a: Spørgeskema om fødevareallergi, allergi over for plaster, kronisk sygdom og 
andre hensyn 
Appendix 2b: Spørgeskema om allergi over for plaster, kronisk sygdom og andre hensyn 
(kontrolskoler) 
Appendix 3: Drop-out skema  
Appendix 4a og 4b: Invitationsbrev til interventionsskoler og kontrolskoler 
Appendix 5a og 5b: Deltagerinformation til interventionsskoler og kontrolskoler 
Appendix 6: Samtykkeerklæring  
Appendix 7: Forældrefuldmagt  
Appendix 8: Pjece om informationsmøde 
Appendix 9: Plakat om informationsmøde 
Appendix 10: Spørgeskema om familiebaggrund, idræt og solvaner 
Appendix 11: Spørgeskema om pubertetsudvikling til forældre med drenge 
Appendix 12: Spørgeskema om pubertetsudvikling til forældre med piger 
Appendix 13: Spørgeskema om barnets kost 
Appendix 14: Spørgeskemaet KIDSCREEN 27  
Appendix 15: SCREENS modificeret spørgeskema  
Appendix 16: Børns søvnvaner spørgeskemaet  
Appendix 17: Uønskede hændelser og samtidig medicin 
Appendix 18: Spørgeskema om dækning af basale psykologiske behov og IM under 
interventionsaktiviteter 

 
 
 
 
 
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Appendix 19: Spørgeskema til børn om physical literacy 
Appendix 20: Spørgeskema til børn om deltagelse i fritidsidræt 
Appendix 21: Spørgeskema om madkompetence og måltidskultur 
Appendix 22: Diplom