Nurture by Nature Feasibility Study

1. Background A newly published report from 2024 highlights significant socioeconomic,geographical, and seasonal disparities in 1‐15 years‐old Danish children's access tooutdoor environments. While the overall time spent outdoors has remained stablesince 2018 (averaging 2 hours and 41 minutes on weekdays and 3 hours and 24 minuteson weekends), the distribution of this time has changed. Most children spend theirweekdays outdoor time in structured settings such as schoolyards and playgrounds,whereas weekend visits to natural areas have increased, particularly among familiesfrom higher socioeconomic status (SES) and in the summer months.The report reveals persistent socioeconomic and regional differences in how childrenengage with nature as also shown in other studies. Children in rural areas andsmaller towns tend to spend more time outdoors overall, benefiting from the closerproximity to nature. In contrast, children in urban areas, particularly in theCapital Region and Region Zealand, use schoolyards, playgrounds, and urban parks,with fewer opportunities for spontaneous nature experiences. On weekends, however,urban families, particularly those from higher educational backgrounds, are morelikely to travel to forests and beaches. Meanwhile, those parents with lowereducational levels face greater barriers to nature access, including transportationlimitations and fewer nearby green spaces. While their total outdoor time iscomparable to other groups, they are significantly less likely to visit publicnatural areas, especially on weekdays.Seasonal differences further impact children's outdoor activity, with outdooractivities more prevalent in summer months and higher engagement with naturecompared to winter. It is important to highlight a crucial distinction betweengeneral outdoor activities which includes playgrounds, yards and streets, and directengagement with natural environments, emphasising that while children may spendconsiderable time outdoors, they do not necessarily interact with nature. The DanishOutdoor Council [Friluftsrådet] stresses the unique benefits of nature exposure,extending beyond conventional outdoor play at playgrounds. The outdoor environmentcan be categorized into two groups, the green outdoor environment which includesnature, and the grey outdoor environment which includes streets and other outdoorenvironments which are not nature.A recent Danish health report indicated that 5.2% of children with a mean age of 6.6years assessed their overall well‐being as low. Another Danish report among childrenaged 0‐9 years stated that at least 16% of young children experience mental healthissues or psychiatric diseases.Exposure to green outdoor environments might promote emotional well‐being, reducestress, fostering social connectedness, support cognitive development and bettersleep quality among children, all of which are crucial for learning abilities anddaily functioning. Furthermore, regular outdoor activities in nature have been shownto reduce ADHD symptoms, improve concentration, and enhance executive functioning.Additionally, it is speculated that nature‐connectedness, e.g. the feeling of beingemotionally and psychologically part of the natural world, fosters stronger socialbonds and greater emotional regulation, all of which contribute to children'spsychological well‐being. However, the evidence for these benefits among youngchildren is still limited as only few studies have been conducted among this agegroup.Findings from our previous qualitative study in rotating kindergartens (the samechildren were biweekly changing their kindergarten setting from rural more greenoutdoor to an urban with much indoor or grey outdoor time) showed that preschoolchildren, while in nature in the rural setting, gained self‐confidence by engagingin risky play (line climbing threes) and overcoming physical obstacles in thechanging natural environment, opposite to the stationary environment presented byformal playgrounds in conventional kindergartens (urban setting). Further, thepreschool teachers also stressed that those children that were more imaginative,engaged in fewer conflicts, were less interrupted during play, and used other motorskills while in nature as compared to when at the conventional playground. Similarresults were found in a cluster randomized intervention study promoting morephysical activity in the intervention kindergartens where significant improvementwas seen in endurance performance. The investigators also showed previously thatduring the time the children spent in the outdoor kindergarten, they were morephysically active as compared to when they were in the conventional kindergartensetting. In our stratified analysis of motor skills by level of maternal education,the investigators showed a tendency towards a lower risk of motor difficulties amongchildren from outdoor‐ compared to children from conventional kindergartens,particularly for those children who had less educated mothers. This suggests thatattending an outdoor kindergarten may improve motor abilities, in particularly amongchildren from low SES families. However, other studies have shown better enduranceperformance only among children from high or medium SES families. These discrepantfindings highlight the need for more studies especially targeted interventions.Given that up to 97% of preschool children attend kindergartens up to 40 hours perweek, a nature‐based intervention in kindergartens presents a practical, low‐cost,and scalable solution to promoting child well‐being by providing an optimal andequitable platform for fostering structured outdoor activities and natureengagement. By integrating nature‐based interventions into early childhoodeducation, municipalities can proactively support children's physical and mentalhealth, while also addressing disparities in access to green spaces. Furthermore,recognizing that the need for outdoor activity is highest during winter, theintervention will be designed to operate year‐round, ensuring that children remainactive, engaged, and exposed to nature even during the colder months.Given the complexity of implementing structured nature‐based interventions inkindergartens, conducting a feasibility study is a critical first step beforeprogressing to a large‐scale cluster randomized controlled trial (CRCT).Kindergartens vary in organizational structures, educational priorities, and staffcapacity, all of which can impact the success of an intervention. A feasibilitystudy will help assess recruitment potential among kindergartens, parentalwillingness to enroll children, and outcome response rates. Additionally, thefeasibility study will identify logistical barriers, ensure ethical considerationsare addressed, and inform necessary adjustments to enhance feasibility, compliance,and data quality before committing to a full‐scale trial. 2. Aim and objectives The Nurture by Nature feasibility trial aims to assess thefeasibility of conducting a future large‐scale pragmatic cluster randomizedcontrolled trial (CRCT) to evaluate the impact of a nature‐based intervention onchildren's mental and physical health. The intervention will be implemented inkindergartens located in areas with a large proportion of social housing andcompared with standard kindergarten activities in similar areas.Specifically, the objectives of the present feasibility study are to investigate 1. completion rate in follow‐up assessment of the Strengths and DifficultiesQuestionnaire (primary outcome), 2. recruitment rate and intervention fidelity (secondary outcomes), 3. completion rate in clinical exploratory outcomes (motor development, physicalactivity levels, sleep, and long‐term stress of the children; sickness absence ofboth children and kindergarten personnel, and stress among kindergarten personneland parents) and 4. safety of the interventionAdditionally, it will explore participants' (e.g. kindergarten personnel and parents)experiences and the acceptability of the intervention in a process evaluation.The findings will inform the feasibility of the larger CRCT and contribute to the designand power calculations necessary for a future trial.2.1. Hypothesis The investigators hypothesise that the Nurture by Nature feasibilitytrial is feasible (e.g. that the participants are willing to participate in the trial,complete assessments, and the intervention is accepted by the participants).3. Study design 3.1. Trial design and framework The trial is a cluster randomisedcontrolled trial (CRCT): a parallel group, cluster randomised controlled trial, whereclusters are randomised to one of two study arms. After randomisation the participants ineach cluster will stay in their assigned treatment arm during the entire trial. Primaryendpoint will be inferred 17‐18 weeks from baseline.3.2. Clusters, Participants and setting The feasibility CRCT will be carried out in 5kindergartens, as defined by the power calculation. The kindergarten management togetherwith the staff responsible for the daily operations of the kindergarten will decidewhether the kindergarten will participate in the CRCT in one of their kindergartengroups. Although the management team of the kindergarten decides whether or not toparticipate in the CRCT, it is up to the eligible participants (the kindergartenpersonnel, and the parents and children) if they give consent and contribute data to thetrial.Each kindergarten can contribute with one pre‐existing group of children, which theinvestigators refer to as a cluster. Each cluster should include at least 11 eligiblechildren consenting to participate.The 5 clusters will be randomised; 3 will be allocated to receive the nature‐basedintervention, and 2 will be allocated to usual activities. Since the clusters arepre‐existing groups within the kindergartens, they will include children not eligible,hence under the age of 4, and those who do not consent to contribute data or withdrawtheir consent. However, although some children in the clusters do not contribute data,all children in the cluster will receive the intervention if randomised to theintervention group.Kindergarten personnel working in the included clusters, will be asked if they want toconsent to contribute data, expectedly n=15.Participants (children and parents or kindergarten personnel) who withdraw during thetrial will not be replaced. Children who join the kindergarten group during theintervention period will not be enrolled in the trial nor contribute with data, but willreceive the intervention if they are int the intervention group.The overall number of participating children, parents and kindergarten personnel will berespectively n=56, n=56 and n=15.From now on in the protocol, the term 'participant' will include children, parents andkindergarten personnel unless other is stated.The trial will take place in the kindergartens and nearby nature settings.4. Study investigation The intervention is a 14‐week structured program during the wintermonths aimed at increasing nature‐based activities to enhance well‐being and health forchildren during kindergarten hours.The usual activities clusters (the control comparator group) will follow usual practiceswhich may include trips outside the kindergarten area as well as indoor and playgroundactivities.4.1. Adherence to the intervention Adherence to the Nurture by Nature intervention willbe monitored and recorded during the trial. Adherence is defined as the number of outdoorsessions and activities done will be registered by kindergarten personnel.5. Outcomes All outcomes will be measured at baseline and again at end‐of‐trial (after 14weeks). In addition, physical activity and sleep will be measured at mid‐trial. The threemost important feasibility outcomes are categorised as primary or secondary, reflectingtheir significance and importance into the decision to progress to a larger clusterrandomised trial.The investigators will assess qualitative and quantitative outcomes in an exploratorymanner.5.1. Feasibility outcomes The feasibility outcomes will be assessed with the 'trafficlight' system, where a set of progression criteria are categorized into red, amber, andgreen, each reflecting different levels of success (green = go, amber = modify, red =stop). The current nature‐based intervention will be deemed feasible if most indicatorsare above the thresholds denoted in the 'green' column and no indicator below thethreshold denoted in the 'red' column. The thresholds for red, amber, and green weredecided by the project management group.5.2. Qualitative outcomes and process evaluation To qualify the primary feasibilityoutcomes (quantitative assessments of recruitment and fidelity rates) the investigatorswill investigate the acceptability of the intervention among the kindergarten personneland parents in a process evaluation which is in line with the Medical Research Council'srecommendations for evaluating complex interventions, thus providing in‐depth insightinto experiences, challenges, and suggestions for improvement.The main research objectives of the process evaluation are: To assess the fidelity ofimplementation (i.e., delivery of the intervention according to the trial protocol). Toexplore how kindergarten personnel and parents respond to and experience theintervention. To identify the key enablers and barriers to implementation.The process evaluation will be based on qualitative interviews with up to 10 parents andup to 10 staff members and supplemented by quantitative measures of implementationfidelity. Fidelity will primarily be assessed as adherence to the intervention protocol.Implementation fidelity will be operationalized as the proportion of intervention weeksin which each intervention cluster delivers at least three planned nature‐basedactivities or outings. This information will be collected through weekly structuredchecklists completed by kindergarten personnel, documenting frequency and duration ofnature‐based activities. Qualitative interviews will be used to explore contextualfactors, participant engagement, and organizational conditions influencing fidelity, andto understand variations in implementation across clusters. Interviews with kindergartenpersonnel will explore how they implement the intervention, and how they experience theintervention in terms of meaning, workability, and compatibility with existing practicesand roles. Implementation will be investigated in relation to a) the specificintervention activities (i.e., nature‐based games) and b) the organizational structure(i.e., being outdoors in all weather in the winter season) that supports the delivery ofthe intervention. Interviews will be audiotaped and transcribed. The data material willbe analyzed using implementation theory.Results based on the process evaluation will tailor the nature‐based intervention for afuture full‐scale CRCT in kindergartens.6. Participant safety 6.1. Safety considerationsThe intervention is generally considered safe, and the investigators do not anticipate anincreased risk of adverse events or reactions in the study. Participants will be informedabout the following potential risks associated with the intervention:• emotional reaction to having hair cut for cortisol sampling Participants will beencouraged to communicate any discomfort or distress to the investigator immediately.6. Trial procedures 6.2.1. Recruitment of kindergartens (clusters)The recruitment of kindergartens will be done using three recruitment ways in denotedorder: 1. Child and Youth Departments of municipalities with larger housing areas in Denmarkand representatives of social housing areas will be contacted and informed about theproject. This will be done by e‐mail or phone. If the management accepts, theinvestigators will contact kindergartens in or near housing areas appointed by thesemunicipalities, via email and phone. If interested, they will receive detailedproject information by email and phone. 2. The investigators will contact the management in kindergartens directly by e‐mail orphone with detailed project information. 3. The investigators will recruit kindergartens directly by social media, newslettersor advertisements in local papers. The management of the kindergartens will then beable to contact us if interested in more information about the trial.6.2.2. Recruitment of children, parents and kindergarten personnel (participants) Uponacceptance by the kindergarten management, they will distribute project information tokindergarten personnel and parents by e‐mail/communication platform like Aula, and placeletters in the children's locker area, posters in the kindergarten. The writteninformation will highlight the randomized nature of the trial that it is voluntary toparticipate, and that children, parents and kindergarten personnel not eligible or who donot consent to contribute data will still receive the intervention. Kindergartenmanagement or personnel will further ask parents for permission to share contactinformation with the investigators. The investigators will then contact the parents andkindergarten personnel to arrange an individual oral information meeting by phone, onlineor on‐site. The participants will be made aware of the possibility of bringing a supportperson (e.g., relative or friend) to the information meeting.6.3. Individual oral information meeting The oral information meeting is plannedindividually , with the possibility of bringing a support person, by phone, online oron‐site in the kindergarten The investigator delivering the oral information will besuitably qualified and experienced and will be authorised to do so by the principalinvestigator.The oral information will include that: ‐ Participation in the trial is voluntary ‐ Participants have the right to minimum 24 hours reflection time before deciding tosign the informed consent or not ‐ Participants can at any time and without giving any reason, withdraw from the trialwithout affecting the potential participant's usual activity in the kindergartenFurther, the oral information will include: project aim, procedures, potential benefitsand risks when participating in the trial, procedures for random findings during theproject, procedures for securing the participants privacy and data protection,information on the trial organization, funding, as well as contact information on theprimary investigator and other key investigators.Children who participate in the trial will receive oral information and will be includedin the conversations with the parents about the trial to the extent that the child inquestion can understand the trial situation. The child's own statements will‐whererelevant‐be taken into account.The investigator will make sure that participants have received and understood theinformation given to them.To be enrolled in the trial inclusion criteria must be fulfilled, thus participants willbe screened accordingly. Participants not eligible will not be asked to consider signingconsent but will be informed that the children and kindergarten personnel are still partof the kindergarten cluster but will not give data.Potential participants which fit the inclusion criteria wishing to consider participationfurther will be contacted by investigators after a few days (min. 24 hours). If they wishto participate in the study, a consent form will be sent to them by email or givendirectly to them in the kindergarten.Participants who wish to sign the consent form right away, can do so and proceed tobaseline assessments (questionnaires). Hair sampling, motor test and accelerometerassessment will be done later but before randomisation.For each participant, the source documentation and eCRFs will document that informedconsent was obtained before participation in the study. The signed informed consent formwill remain in each participant's study file and will always be available.6.4. Assessments and assessment timings Both assessment visits (baseline and end‐of‐trialassessments) will be conducted at the included kindergartens where the children feelsafe.6.4.1. Baseline assessment The baseline assessment visit will be carried out in thethree‐week period (termed 'week 0') before the randomization and the intervention begin.At baseline the following procedures will be performed in the denoted order: 1. Assessment of child medical history and parental sociodemographic informationentered in RedCAP 2. The parents fill in the outcome questionnaires in RedCAP 3. Activity tracker is given, and instructions for returning the devise are given 4. Scheduling plan with dates for the mid‐trial (physical activity and sleep measure)and end‐of‐trial assessments 5. Sampling of child hair (investigator assessment) 6. Motor test (investigator assessment) The baseline hair sampling and motor test willbe held in the kindergartens by trained investigators. Parents can be present, butit is not a demand.Kindergarten personnel will fill out baseline questionnaire during kindergarten hours orat home via e‐boks.6.4.2. Mid‐trial assessment The mid‐trial assessment will be caried out in the two‐weekperiod (termed 'week 7').At week seven of intervention the child will again wear the activity tracer to measurephysical activity and sleep for four consecutive days. This will be given at thekindergarten by the investigators. The parents are welcome to be present, but it is not amust.6.4.3. During the trial Text messages by mobile phone will be send weekly to the parentsincluding a question related to child absence the last week.Information on kindergartens personnel's sickness absence will be collected by theinvestigators from kindergarten personnel monthly.Kindergarten personnel report daily activities performed related to the intervention(nature trips and activities carts used).6.4.4. End‐of‐trial assessment The end‐of‐trial assessment visit will be carried out inthe two‐week period (termed 'week 15‐16') after the intervention has ended and no laterthan 3 weeks after the last intervention week.The end‐of‐trial assessment will be held in the kindergartens where the children will bepresent. It is optional for the parents to be present or to answer the questionnaireonline. The investigators will ask the parents what they prefer. At end‐of trial thefollowing procedures will be done in the denoted order: 1. Information about the assessments 2. The parents fill in questionnaires 3. Questions about adverse events 4. Sampling of child hair (investigator assessment) 5. Motor test (investigator assessment) 6. Activity tracker is given, and instructions for returning the devise are givenKindergarten personnel will fill out end‐of‐trial questionnaire during kindergartenhours or at home via e‐boks.Assessments performed outside these time limits will be registered as protocoldeviations. 7. Biological material 7.1. Research biobank ‐ hair samples for cortisol measurementHair samples will be collected to measure cortisol levels, which serve as anindicator of chronic stress over time. Hair samples provide a reliable, non‐invasivemethod to assess cortisol accumulation over several months, as hair growsapproximately 1 cm per month, allowing a retrospective assessment of the stresslevels. This will inform us whether the nature‐base intervention affect chronicstress in the children. 8. Quality assurance and quality control The trial will be conducted in compliance withthe study protocol. Detailed instructions and Standard Operating Procedures will bedeveloped for specific tasks, as needed. 9. Statistical considerations 9.1. Determination of Sample Size and ProgressionCriteria The investigators have approached setting the sample size using Lewis etal.'s procedure to ensure adequate sample sizes for the feasibility study. Thismethod means that should the true observed proportion be at or above the greenthreshold, then the sample is sufficiently large to be confident that the observedproportion will be at or below the red threshold in only 5% of tests. The samplesize is set on the highest number; here, 56 children are divided into 33 in theintervention groups (3 groups) and 23 in the control groups (2 groups), for 90%power. No statistical testing is needed in this feasibility study. In thisfeasibility study, progression depends upon not having any indicator in the red zoneand having all or nearly all green criteria achieved.9.2. General statistical approach As this is a feasibility study, the primaryoutcomes will be reported descriptively as proportions and percentages. The primaryfocus is on assessing the feasibility parameters (e.g., data completeness,recruitment, and fidelity), not hypothesis testing. Changes from baseline toend‐of‐trial in secondary and exploratory outcomes will be summarized descriptivelyand presented with 95% confidence intervals where applicable. Given the small samplesize, these findings will be interpreted cautiously, as they are not intended toestablish causal relationships. All statistical tests, if performed, will betwo‐sided and statistical significance will be claimed if the computed p‐value isequal to or less than 0.05. However, all exploratory outcomes will be reported aspreliminary and exploratory findings, intended to inform the design and analysisplan of future, more definitive trials.9.3. Trial conduct The Nurture by Nature intervention is non‐invasive andnon‐medical with components focusing on nature, motor development, peerinteractions, physical activity etc., that are commonly used in society and are notgenerally considered harmful. All participants will, however, be closely monitoredfor potential adverse reactions, but the investigators anticipate no ethical issues.The intervention is considered justifiable in a health research ethics perspective.The trial will be conducted in compliance with the protocol, and The HelsinkiDeclaration and meets the requirements of the regional ethics committees. Theproject will be carried out in full compliance with the General Data ProtectionRegulation (GDPR) and the Danish Data Protection Act, ensuring that all dataprotection requirements are strictly adhered to throughout the study period. Thetrial is registered in the Capital Region's research project register (Privacy), anddata protection compliance has been reviewed and approved by Forskningsjura inaccordance with the Danish Data Protection Act and the GDPR. Any substantialdeviation from the protocol will only be implemented after review and approval fromrelevant regulatory authorities. Any deviation, however minor, will be documentedand made available with the protocol. 10. Reimbursement In recognition of the lack of benefit for attending the assessmentvisits, the children will receive a gift card to Fætter BR of DKK 150, and thekindergarten personnel will receive a cinema gift card for two (valued around DKK350), for completing the end‐of‐trial assessment visit. No compensation or transportreimbursement will be paid for attending any visits related to the Nurture by Natureintervention.If the sponsor or the kindergarten management discontinues a participant from the trial,the children and the kindergarten personnel will receive the reimbursement. Whereaschildren who withdraws from the trial after baseline assessment but before theend‐of‐trial assessment will receive a reimbursement gift card to Fætter BR of DKK 75.Kindergarten personnel who withdraw from the trial before end‐of‐trial assessment willstill receive the reimbursement.