ITASPA is a worksite intervention, conducted in a stepped wedge design (Fig. 1) . The stepped wedge design are assumed to increase the willingness to participate as it allows all workers to receive the intervention. The workers function as their own control and thereby, the stepped wedge design allows for an effect-evaluation, mimicking an RCT design.
The study was approved by the Danish data protection agency (journal number REG-034–2021) and the Ethics Committee for the regional capital in Denmark (journal number SJ-927) and will be conducted in accordance with the Helsinki declaration. The first version of the Clinicaltrials.gov registration for ITASPA is registered on May 19, 2023 (NCT05866978).
To increase the transferring of the WIN program to a broad variety of Danish worksites, both public and private worksites are aimed to be enrolled. The worksites will be enrolled on basis of their willingness to perform the ITASPA activities during paid worktime and participation in the scientific evaluation of the ITASPA project. Workers will be included in the scientific evaluation of the ITASPA project by the following criteria: aged 18 – 67 years old at baseline; employed at one of the enrolled worksites ≥ 20 h/week; not being pregnant; ability to understand and speak Danish or English; providing an informed signed consent prior to participation.
An information meeting at the worksites will be held before initiating the intervention. At the meeting, the background and aim of the ITASPA project are introduced. All workers will be invited to fill out a screening questionnaire in which they can choose to sign up for participation in the scientific evaluation.
The sample size estimations were based on effect expectations in MSDs, on a scale ranging from 0–10, an expected variance of 2.1, an Alpha value of 0.05, and a power of 80%. The estimation showed a cluster size of 65 participants to identify a statistically significant effect, at a 5% level, of the worksite intervention.
Development, planning, and preparation of the itaspa intervention
Organization of the project
The ITASPA project will be organized by a steering group consisting of the ITASPA project managers, representatives from the senior management at the enrolled worksites, and the ITASPA facilitators from the Department of Occupational and Social Medicine at Holbæk Hospital, Denmark (Fig. 2). Moreover, the steering group includes an advisory board consisting of the developers of the WIN program and TWH concept. The advisory board will provide information about international experiences with integrated worksite interventions to assist the development of worksite health interventions in Denmark.
Development of ITASPA package of change
The steering group will collect and choose relevant tools and methodologies to establish a Package of Change. This package encompasses descriptions of the processes in ITASPA, evidenced examples of previous successful worksite interventions similar to ITASPA, and the present work environment policy, program, and practice at the enrolled worksites.
ITASPA committee at the worksite
At each worksite, an ITASPA committee will be established (Fig. 2). In accordance with an integrated approach, the members will represent the existing cooperative work environment fora, the workers, union and safety representatives, and relevant staff functions (HR, etc.). The worksites choose a chairperson for the ITASPA committee, who will be leading the interventions and act as the contact to the ITASPA facilitators. Ideally, the chairperson of the committee is a line manager who has knowledge of change management and communicates with both employees and senior management.
Education of the ITASPA committee
Before the offset of the intervention, the ITASPA committee will be educated by the ITASPA facilitators in the ITASPA concept and the Package of Change.
The education session will be carried out as a workshop (education workshop, Fig. 3) at the enrolled worksites during paid work time. The workshop lasts 3 h and involves training in collaborative methodology, the models of improvements (e.g. the model of Change), the plan-do-study-act (PDSA) cycle, and the integrated concept of worksite intervention used in ITASPA . A central theme for the education workshop is the Model of Improvement which consists of two parts. The first brainstorming part includes three key questions aiming to guide the assessment of which initiatives each worksite should focus on: 1) What are we trying to accomplish?, 2) How will we know that a change is an improvement?, and 3) What changes can we make that will result in an improvement?) . The second part is the “test part”, which consist of the PDSA cycles:
• Plan: Thorough planning of the initiative, clarification of expectations of outcomes, and agreements on data collection.
• Do: Implementation of the planned actions as well as data collection.
• Study: Reflection on effect and learning, data analysis, and identification of unintended negative and positive consequences.
• Act: Assessment of either continuation of implementation, adjustments, or testing a new initiative.
The experiences from each cycle will systematically be transferred to the next. Thus, continuous improvements and/or adjustments will be conducted.
Workshops for choosing, planning, studying, and evaluating initiatives
In workshops (learning workshops, Fig. 3), the ITASPA committees will develop their initiatives based on their own experiences of their work environment. Methods used in the Australian WIN study  will guide the ITASPA committee in this process. Finally, success criteria will be set, and the committee will decide what data should be used to evaluate the effect of the initiative. All decisions will be documented by the ITASPA facilitators.
ITASPA committee network
Following the first implementation period, the ITASPA committees from all participating worksites will be invited to join a network. In this network, the ITASPA committees learn from each other, share ideas and give each other feedback. Each ITASPA committee will describe their worksite initiatives, the preliminary intended and unintended effects, and the facilitating factors and barriers for testing and implementation of their initiatives. The network meetings will be facilitated by the project manager and an ITASPA facilitator, who will lead the discussion and give feedback.
Periods of implementation (approximately 3 months)
Between the workshops the worksites will test and implement their initiatives, e.g. using the Model of Improvement from the ITASPA Package of Change. At each worksite, the ITASPA Facilitators participate in two of the ITASPA Committee’s meetings every implementation period to support the worksites and ensure an integrated approach.
Data collection and study materials
The screening questionnaire contains questions about job title, sex, age, country of birth, years lived in Denmark, job seniority, education, smoking, alcohol consumption, level of MSDs, safety culture at the worksite, psychosocial wellbeing, and diagnosis with one or more of the following diseases: asthma, allergy, diabetes, cardiovascular or skin diseases, and mental disorders.
Data collection at baseline and after the periods of implementation
The data collection will be conducted at baseline, before the first learning workshop, and after each period of implementation, approximately every third month throughout the year of scientific evaluation, summing up to five data collections in total (Fig. 4). The data collection will be conducted by the ITASPA facilitators at a health check encompassing a questionnaire-based interview and objective measurements.
The questionnaire-based interview includes questions about the level of physical activity in occupational and leisure time, eczema, and self-reported health. Functionality will be measured by the ICF-based Work Rehabilitation Questionnaire (WORQ) (https://myworq.org/). The Short Form of the Örebro Musculoskeletal Pain Screening Questionnaire will be used to measure MSDs . Psychosocial wellbeing will be measured via the Health Survey SF-12 . Finally, safety culture will be measured by the Nordic Occupational Safety Climate Questionnaire (NOSACQ-50) .
The objective measurements include body weight (kg), height (m), percent body fat, resting heart rate (beats per minute), and blood pressure (mmHg). Bodyweight, percent body fat, and height will be measured while the participant is wearing light clothes and no shoes. The estimated weight of clothes (1.5 kg) will be subtracted from body weight. Percent body fat will be estimated by bioelectric-impedance-analysis. Both body weight and percent body fat will be measured by a Segmental Body Composition Monitor, Innerscan V, BC545N (TANITA, produced in Japan). If participants have a pacemaker or are pregnant, the analysis of percent body fat will not be made. Body height will be measured on a mobile stadiometer Seca 213 (Seca, produced in China). Body mass index (BMI) will be estimated by the equation of BMI = (body weight (kg)/body height (m)2). Resting heart rate and blood pressure will be measured three times on the left arm after 15 min of sitting at rest using an Omron Model M3, automatic upper arm BP monitor (Omron healthcare, produced in Vietnam).
At baseline, and after the periods of implementation, we will collect data on sickness absence, staff turnover, and productivity combined with interviews with the chairperson of the ITASPA committee. These data will be collected for a financial evaluation of the overall ITASPA intervention at each worksite.
Process and implementation evaluation
The implementation of the initiatives will be tracked by the research group using quantitative and qualitative methods, allowing for triangulation of data across methodologies .
The quantitative process tracking will be based on the data collected by the ITASPA committees during the implementation periods. Data will be used to monitor the fidelity and dose (the amount of intervention delivered) of the planned initiatives, following the principles of process evaluation .
The qualitative process tracking will be based on focus group interviews consisting of members of the ITASPA committee at each worksite after the second learning workshop and an individual semi-structured interview with the chairperson of the ITASPA committee midway through each implementation period. Data on implementation experiences will be collected and feedback on the effect of the chosen outcome, for the particular period of implementation, will be given. This has two purposes: 1) to collect data on factors facilitating and hindering the implementation of the initiatives, and 2) to give feedback to the worksites regarding the effect of the chosen outcome, based on the initiative in the ongoing period of implementation. The focus groups are directed by a semi-structured interview guide including questions about the specific interventions and reflections on intervention delivery, such as observations on contextual factors, barriers, and facilitating factors of intervention implementation . Thus, the interviews will be tailored to the context and initiative at each worksite and provide input for the next period of implementation. Conversation objectives, topics, and materials discussed will be documented.
Data from the health checks will be used to evaluate the effect of the initiatives after each implementation period. Preliminary descriptive analysis will be conducted and discussed with the ITASPA committee after each implementation period to ensure that only beneficial and effective initiatives are continued in the next implementation period and to guide the development of future initiatives.
Descriptive analyses of baseline data and health check data will be conducted after the implementation periods. Frequencies and distribution of participants across variables will be reported (amount and percentages). Differences between baseline data and the follow-ups within and between participating worksites will be reported by the use of chi2 test for categorical variables and paired and independent sampled t-test for continuous variables. Furthermore, differences in baseline data between those who want to participate and those who do not want to participate will be analyzed. Where appropriate, results are presented as the mean and standard deviation (Mean ± SD) or visualized in graphs and histograms.
Effect evaluation and analyses
The effect evaluation will be based on a mixed-methods approach, where questionnaire data on MSDs, psychosocial wellbeing, safety culture, and workability will be measured based on the questionnaire-based interviews. The quantitative data will be analyzed based on the intention-to-treat principle in linear mixed models with random slope and intercept. The repetitive measurements within and between participants will be accounted for by nesting participants in clusters at the worksite level. The intervention will be included as a categorical variable with two levels, comparing the intervention period with the control period as a fixed effect in the model. Intercorrelation of repeated measurements will be included in the models as a random effect. Participants missing data on exposure or outcome variables will be excluded from analyses. All analyses will be conducted in SAS version 9.4 and/or SPSS version 27.0.
Evaluation of the implementation
Experiences from each interview midway through the periods of implementation will be analyzed in an overall analysis based on the Model of Knowledge to Action Cycle . This analysis will be supplied by focus group interviews with the ITASPA committee chairpersons at the end of the intervention period.
The implementation of the project within worksites depends on the consent of the top management. At learning workshops, worksites will be encouraged to share experiences with their work environment initiatives. During this process, company-sensitive information may be shared. Thus, in workshops, it will be pointed out that a duty of confidentiality is expected among companies.
Personal information will be obtained from the participants about safety at work, workability, MSD, and psychosocial well-being. Data will be stored and processed as prescribed by the Danish Data Protection Agency and will only be available to researchers involved in this study. Data will be anonymized in analyses and feedback to the worksite will be provided anonymously, and in groups of at least 10 participants. The ITASPA facilitators will discuss any unforeseen ethical aspects with the worksites if they experience any. In this context, the steering group and reference group will be involved as potential sparring partners.