Night Shift WorkWHReduNCT07848607
Night Work Hours Reduction Trial
A study testing Reduced Working Hours (from 38h15minutes to 36h) in people with Night Shift Work and Sickness Absence, run by Finnish Institute of Occupational Health at 3 sites in Finland.
Trial summary
The primary aim of this study is to investigate the effects of reducing weekly working hours among employees working night shifts regularly from 38 hours 15 minutes to 36 hours on payroll-based, objective working-hour characteristics, sickness absence, and workforce retention. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Night Shift Work, Sickness Absence
- What is being tested?
- Reduced Working Hours (from 38h15minutes to 36h)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 3 sitesFinland
- Study dates
- 30 Sep 2026to 1 Apr 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Employment in one of the participating Finnish wellbeing services counties. Employees working in work units participating in the study. For the primary analyses, employees who work regular night shifts. Employees with available administrative, payroll-based working-hour and employment records.
Who cannot join
- Exclusive day workers. Employees performing shift work that does not include night shifts. For the primary analyses, employees not engaged in regular night work.
- Employees not performing regular night work may be included in secondary analyses evaluating workplace-level spillover effects.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Finland3 sites
Kainuun hyvinvointialue
Kajaani
Päijät-Hämeen hyvinvointialue
Lahti
Pohjois-Pohjanmaan hyvinvointialue
Oulu
About this study
Official title: Trial of Reduced Working Hours Among Regular Night Shift Workers in Public Health and Social Care
The primary aim of this study is to investigate the effects of reducing weekly working hours among employees working night shifts regularly from 38 hours 15 minutes to 36 hours on payroll-based, objective working-hour characteristics, sickness absence, and workforce retention. The secondary aim is to investigate experiences of promoting and hindering factors related to the working-hour reduction, its implementation process, and perceived benefits and challenges.
The working-hour reduction will be implemented in three Finnish wellbeing services counties with different starting dates, the first being in late September 2026 and the latest in early 2027. The working-hour reduction has been agreed upon by the parties to the collective agreement for Finnish public social and health care. Thus, intervention is a so-called natural experiment in a real-life setting.
The effects of the intervention will be evaluated using a quasi-experimental design with staggered, non-randomized implementation across participating counties. Administrative, payroll-based, employer-owned working-hour data, including records of sickness absences without any medical or health information and other absences (including unpaid, education, and childcare), will be used to compare changes before and during the intervention among work units participating in the working-hour reduction. The investigation will also utilize matched work units that do not participate in the reduction (i.e., intervention) as control units (i.e., continuing standard working-hour arrangements).
Read the detailed description
Introduction Night work is associated with increased fatigue, impaired recovery, sickness absence, and difficulties in maintaining long-term work ability (Kecklund \& Axelsson, 2016; Krutova et al., 2022). In addition, night work has been classified as probably carcinogenic to humans (IARC Working Group on the Identification of Carcinogenic Hazards to Humans, 2020). One potential strategy for reducing the burden associated with night work is to decrease total working hours while maintaining service quality and workforce availability. Although organizations have experimented with reduced working hours (Hanbury et al., 2023; Neubert et al., 2022; Voglino et al., 2022) detailed examination of large-scale workplace interventions for the effects of working-hour reduction among night workers using administrative, payroll-based working-hour data remains very limited.
The present study evaluates a reduction in weekly working hours from 38 hours 15 minutes to 36 hours among employees working night shifts in Finnish wellbeing services counties using administrative, payroll-based, employer-owned working-hour data (see e.g., Härmä et al., 2015; Härmä et al., 2025; Ropponen et al., 2024).
Intervention The natural experiment of working hour reduction, later referred to as the intervention, consists of reducing contractual weekly working hours from 38 hours 15 minutes to 36 hours among employees working regular night shifts. At the earliest, the implementation will begin in late September 2026 in three Finnish wellbeing services counties. Due to organizational decision-making and operational requirements, the intervention will be introduced at different time points (from September 2026 to early 2027) in different counties in a non-randomized manner using a staggered implementation design.
The participating organizations will modify shift schedules and staffing arrangements to accommodate the reduced working hours while ensuring continuity of services among those work units that have voluntarily decided to participate in the intervention. Control units consisting of matched work units will continue operating under the standard working-hour arrangement of 38 hours 15 minutes per week.
Data Sources The study will primarily utilize administrative, payroll-based, employer-owned working-hour data (see e.g., (Harma et al., 2015; Härmä et al., 2025; Ropponen et al., 2024)). The data will include day-to-day information on shift start and end times, shift duration, number of morning, day, evening and night shifts, number of consecutive shifts, weekend work, overtime hours, sickness absence (without any health or medical information), other absences and absence types (such as childcare or education), job title, work contracts and employment start and end dates. The data also includes information on organizational structure, including work units. The data will be processed both at the individual- and work unit-level as well as annual and scheduling-period summary measures.
Study Design The study will employ a non-randomized quasi-experimental design. The impact of the reduced working-hours (i.e., intervention) will be evaluated by comparing (1) changes before and during the implementation within intervention units, (2) changes between the intervention and the control units, and (3) changes across wellbeing services counties with different implementation schedules using a difference-in-differences framework (see, e.g., Turunen et al., 2020 and Turunen et al., 2025 for a similar approach in evaluating a participatory scheduling program implementation and national legislative change reducing the occurrence of quick returns, defined as rest periods of less than 11 hours between shifts, respectively).
The staggered introduction of the intervention across the three wellbeing services counties allows the use of longitudinal and difference-in-differences approaches to strengthen causal inference.
Baseline data will be collected from employer records before and during the implementation. Employer records will be available from the beginning of 2023 through the end of 2027, providing approximately 47 months of pre-intervention data and at least 15 months during the intervention, depending on the intervention start date in each county.
- Conditions
- Night Shift Work, Sickness Absence
- Being tested
- Reduced Working Hours (from 38h15minutes to 36h)
- Keywords
- Working Time Reduction, Reduced Working Hours, Night Work, Night Shift Work, Healthcare Workers, Sickness Absence, Employee turnover, Payroll-Based Working Hour Data, Quasi-experimental Study
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Reduced Working Hours (from 38h15minutes to 36h)Other
Reduced Working Hours (from 38h15minutes to 36h) for those conducting night shift work regularly
| Study group | Role | What they receive |
|---|---|---|
| Reduced working hours (36 h) | Experimental | Reduced working hours (36 h) for those who regularly conduct night shift work. Receives: Other: Reduced Working Hours (from 38h15minutes to 36h) |
| Standard working hours (38 h 15 min) | No intervention | Standard working hours (38 h 15 min) for those whose organisation or unit did not choose to participate in the trial. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Sickness Absence Rate
Percentage of working time lost due to sickness absence, derived from administrative, payroll-based employer records. No medical or diagnostic information will be collected.
Measured: From enrollment to the end of treatment at 66 weeks.
Employee Turnover
Termination of employment during the follow-up period, derived from employment records.
Measured: From enrollment to the end of treatment at 66 weeks.
Retention of Employees Performing Night Work
Proportion of employees performing regular night work who remain employed and performing night shifts during the follow-up period.
Measured: From enrollment to the end of treatment at 66 weeks.
Total Weekly Working Hours
Average number of paid working hours per week, derived from administrative, payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Number of Morning, Day, Evening, and Night Shifts
Number or rate of shifts worked during each scheduling period, categorized according to shift type (morning, day, evening, and night) using employer payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Secondary outcomes (13)
Number of Sickness Absence Episodes
Total number of sickness absence episodes recorded in administrative payroll-based employer records.
Measured: From enrollment to the end of treatment at 66 weeks.
Total Sickness Absence Days from Short Episodes (1-5 days) of Sickness Absence
Total number of sickness absence days from short episodes of sickness absence recorded in administrative payroll-based employer records.
Measured: From enrollment to the end of treatment at 66 weeks.
Short-Term Sickness Absence Episodes (1-5 Days)
Number of sickness absence episodes lasting 1-5 consecutive calendar days.
Measured: From enrollment to the end of treatment at 66 weeks.
Number of Consecutive Shifts
Number of instances in which employees work consecutive shifts without a day off, derived from administrative, payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Overtime Hours
Total number of overtime hours worked during each scheduling period, derived from administrative, payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Recovery Periods Between Shifts
Duration of rest periods between consecutive shifts, calculated from shift start and end times recorded in payroll-based working-hour data.
Measured: From enrollment to the end of treatment at 66 weeks.
Number of Quick Returns (<11 Hours Between Shifts)
Number of occurrences in which the interval between the end of one shift and the start of the next shift is less than 11 hours, derived from payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Weekend Work
Number of shifts worked during weekends, derived from administrative, payroll-based working-hour records.
Measured: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Recovery
Employees', supervisors', shift planners', and managers' perceptions of the effects of the working-hour reduction on recovery from work, assessed using semi-structured interviews for focus group including employees, shift planners and management.
Measured: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Work-Life Balance
Participants' perceptions of the effects of the working-hour reduction on work-life balance, assessed using semi-structured interviews for focus group including employees, shift planners and management.
Measured: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Workload and Staffing
Participants' perceptions of the effects of the working-hour reduction on workload, staffing adequacy, and continuity of services, assessed using semi-structured interviews for focus group including employees, shift planners and management.
Measured: From enrollment to the end of study at 66 weeks.
Implementation Process
Experiences regarding the organization and implementation of the working-hour reduction, including facilitating factors and implementation challenges, assessed using semi-structured interviews for focus group including employees, shift planners and management.
Measured: From enrollment to the end of study at 66 weeks.
Perceived Advantages and Disadvantages of the Intervention
Participants' views regarding positive consequences, unintended effects, challenges, and recommendations for future implementation of reduced working hours, assessed using semi-structured interviews for focus group including employees, shift planners and management.
Measured: From enrollment to the end of study at 66 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2026
- Study start30 Sep 2026 (estimated)
- Primary completion28 Feb 2028 (estimated)
- Study completion1 Apr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (11)Papers the sponsor has linked to this study.
- Other trials for Night Shift WorkStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- Participants are effectively in one of two concurrent conditions: 1. Reduced working hours (36 h) 2. Standard working hours (38 h 15 min)
- Masking
- None (open label)
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Finnish Institute of Occupational Health
- Sponsor type
- University, hospital or other
- Collaborators
- Finnish Work Environment Fund
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07848607
- Sponsor's protocol ID
- WHRedu-36
- Acronym
- WHRedu
- Status last verified
- Sep 2026
- First submitted
- 17 Sep 2026
- Last updated
- 30 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because the study uses employer-owned administrative and payroll-based records containing potentially identifiable employee information. Data sharing is restricted by data protection regulations, data use agreements, and organizational policies of the participating wellbeing services counties.
Publications
Voglino G, Savatteri A, Gualano MR, Catozzi D, Rousset S, Boietti E, Bert F, Siliquini R. How the reduction of working hours could influence health outcomes: a systematic review of published studies. BMJ Open. 2022 Apr 1;12(4):e051131. doi: 10.1136/bmjopen-2021-051131.
PubMed 35365508Turunen J, Karhula K, Ropponen A, Shiri R, Hamalainen K, Ervasti J, Koskinen A, Haavisto O, Sallinen M, Pehkonen J, Harma M. Evaluating quick return restrictions on sickness absence in healthcare employees: A difference-in-differences study. Int J Nurs Stud. 2025 Mar;163:104996. doi: 10.1016/j.ijnurstu.2025.104996. Epub 2025 Jan 10.
PubMed 39836993Turunen J, Karhula K, Ropponen A, Koskinen A, Hakola T, Puttonen S, Hamalainen K, Pehkonen J, Harma M. The effects of using participatory working time scheduling software on sickness absence: A difference-in-differences study. Int J Nurs Stud. 2020 Dec;112:103716. doi: 10.1016/j.ijnurstu.2020.103716. Epub 2020 Jul 14.
PubMed 32736788Ropponen A, Hirvonen M, Kuusi T, Harma M. Concurrent Trajectories of Objectively Measured Insufficient Recovery and Workload Among a Cohort of Shift Working Hospital Employees: Quantitative Empirical Research. Nurs Open. 2024 Nov;11(11):e70101. doi: 10.1002/nop2.70101.
PubMed 39571045Neubert, S., Bader, C., Hanbury, H., & Moser, S. (2022). Free days for future? Longitudinal effects of working time reductions on individual well-being and environmental behaviour. Journal of Environmental Psychology, 82, 101849. https://doi.org/https://doi.org/10.1016/j.jenvp.2022.101849
Krutova O, Koskinen A, Peutere L, Ervasti J, Virtanen M, Harma M, Ropponen A. A Longitudinal Study on Trajectories of Night Work and Sickness Absence among Hospital Employees. Int J Environ Res Public Health. 2022 Jul 3;19(13):8168. doi: 10.3390/ijerph19138168.
PubMed 35805827Kecklund G, Axelsson J. Health consequences of shift work and insufficient sleep. BMJ. 2016 Nov 1;355:i5210. doi: 10.1136/bmj.i5210.
PubMed 27803010IARC Working Group on the Identification of Carcinogenic Hazards to Humans. Night Shift Work. Lyon (FR): International Agency for Research on Cancer; 2020. Available from http://www.ncbi.nlm.nih.gov/books/NBK568195/
PubMed 33656825Harma M, Karhula K, Turunen J, Koskinen A, Shiri R, Sallinen M, Vanttola P, Haavisto O, Hakola T, Ropponen A. Working time traffic light recommendations: development, use, and implementation in the Finnish social and healthcare. Ind Health. 2026 May 20;64(3):214-232. doi: 10.2486/indhealth.2025-0082. Epub 2025 Sep 15.
PubMed 40958582Harma M, Ropponen A, Hakola T, Koskinen A, Vanttola P, Puttonen S, Sallinen M, Salo P, Oksanen T, Pentti J, Vahtera J, Kivimaki M. Developing register-based measures for assessment of working time patterns for epidemiologic studies. Scand J Work Environ Health. 2015 May 1;41(3):268-79. doi: 10.5271/sjweh.3492. Epub 2015 Mar 19.
PubMed 25788103Hanbury, H., Illien, P., Ming, E., Moser, S., Bader, C., & Neubert, S. (2023). Working less for more? A systematic review of the social, economic, and ecological effects of working time reduction policies in the global North. Sustainability: Science, Practice and Policy, 19(1), 2222595. https://doi.org/10.1080/15487733.2023.2222595
Study at a glance
From the registry record, last updated by the sponsor on 30 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Trial of Reduced Working Hours Among Regular Night Shift Workers in Public Health and Social Care
- ClinicalTrials.gov ID
- NCT07848607
- Acronym / sponsor ID
- WHRedu / WHRedu-36
- Conditions
- Night Shift Work, Sickness Absence
- Keywords
- Working Time Reduction, Reduced Working Hours, Night Work, Night Shift Work, Healthcare Workers, Sickness Absence, Employee turnover, Payroll-Based Working Hour Data
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Finnish Institute of Occupational HealthUniversity, hospital or other
- Collaborators
- Finnish Work Environment Fund
- Study start
- 30 Sep 2026 (estimated)
- Primary completion
- 28 Feb 2028 (estimated)
- Study completion
- 1 Apr 2028 (estimated)
- First posted
- 30 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary aim of this study is to investigate the effects of reducing weekly working hours among employees working night shifts regularly from 38 hours 15 minutes to 36 hours on payroll-based, objective working-hour characteristics, sickness absence, and workforce retention. The secondary aim is to investigate experiences of promoting and hindering factors related to the working-hour reduction, its implementation process, and perceived benefits and challenges.
The working-hour reduction will be implemented in three Finnish wellbeing services counties with different starting dates, the first being in late September 2026 and the latest in early 2027. The working-hour reduction has been agreed upon by the parties to the collective agreement for Finnish public social and health care. Thus, intervention is a so-called natural experiment in a real-life setting.
The effects of the intervention will be evaluated using a quasi-experimental design with staggered, non-randomized implementation across participating counties. Administrative, payroll-based, employer-owned working-hour data, including records of sickness absences without any medical or health information and other absences (including unpaid, education, and childcare), will be used to compare changes before and during the intervention among work units participating in the working-hour reduction. The investigation will also utilize matched work units that do not participate in the reduction (i.e., intervention) as control units (i.e., continuing standard working-hour arrangements).
Detailed description
Introduction Night work is associated with increased fatigue, impaired recovery, sickness absence, and difficulties in maintaining long-term work ability (Kecklund \& Axelsson, 2016; Krutova et al., 2022). In addition, night work has been classified as probably carcinogenic to humans (IARC Working Group on the Identification of Carcinogenic Hazards to Humans, 2020). One potential strategy for reducing the burden associated with night work is to decrease total working hours while maintaining service quality and workforce availability. Although organizations have experimented with reduced working hours (Hanbury et al., 2023; Neubert et al., 2022; Voglino et al., 2022) detailed examination of large-scale workplace interventions for the effects of working-hour reduction among night workers using administrative, payroll-based working-hour data remains very limited.
The present study evaluates a reduction in weekly working hours from 38 hours 15 minutes to 36 hours among employees working night shifts in Finnish wellbeing services counties using administrative, payroll-based, employer-owned working-hour data (see e.g., Härmä et al., 2015; Härmä et al., 2025; Ropponen et al., 2024).
Intervention The natural experiment of working hour reduction, later referred to as the intervention, consists of reducing contractual weekly working hours from 38 hours 15 minutes to 36 hours among employees working regular night shifts. At the earliest, the implementation will begin in late September 2026 in three Finnish wellbeing services counties. Due to organizational decision-making and operational requirements, the intervention will be introduced at different time points (from September 2026 to early 2027) in different counties in a non-randomized manner using a staggered implementation design.
The participating organizations will modify shift schedules and staffing arrangements to accommodate the reduced working hours while ensuring continuity of services among those work units that have voluntarily decided to participate in the intervention. Control units consisting of matched work units will continue operating under the standard working-hour arrangement of 38 hours 15 minutes per week.
Data Sources The study will primarily utilize administrative, payroll-based, employer-owned working-hour data (see e.g., (Harma et al., 2015; Härmä et al., 2025; Ropponen et al., 2024)). The data will include day-to-day information on shift start and end times, shift duration, number of morning, day, evening and night shifts, number of consecutive shifts, weekend work, overtime hours, sickness absence (without any health or medical information), other absences and absence types (such as childcare or education), job title, work contracts and employment start and end dates. The data also includes information on organizational structure, including work units. The data will be processed both at the individual- and work unit-level as well as annual and scheduling-period summary measures.
Study Design The study will employ a non-randomized quasi-experimental design. The impact of the reduced working-hours (i.e., intervention) will be evaluated by comparing (1) changes before and during the implementation within intervention units, (2) changes between the intervention and the control units, and (3) changes across wellbeing services counties with different implementation schedules using a difference-in-differences framework (see, e.g., Turunen et al., 2020 and Turunen et al., 2025 for a similar approach in evaluating a participatory scheduling program implementation and national legislative change reducing the occurrence of quick returns, defined as rest periods of less than 11 hours between shifts, respectively).
The staggered introduction of the intervention across the three wellbeing services counties allows the use of longitudinal and difference-in-differences approaches to strengthen causal inference.
Baseline data will be collected from employer records before and during the implementation. Employer records will be available from the beginning of 2023 through the end of 2027, providing approximately 47 months of pre-intervention data and at least 15 months during the intervention, depending on the intervention start date in each county.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants are effectively in one of two concurrent conditions: 1. Reduced working hours (36 h) 2. Standard working hours (38 h 15 min)
| Arm | Type | Receives |
|---|---|---|
| Reduced working hours (36 h) | Experimental | Other: Reduced Working Hours (from 38h15minutes to 36h)Reduced working hours (36 h) for those who regularly conduct night shift work. |
| Standard working hours (38 h 15 min) | No intervention | –Standard working hours (38 h 15 min) for those whose organisation or unit did not choose to participate in the trial. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Employment in one of the participating Finnish wellbeing services counties. Employees working in work units participating in the study. For the primary analyses, employees who work regular night shifts. Employees with available administrative, payroll-based working-hour and employment records.
Key exclusion criteria (2 listed)
- Exclusive day workers. Employees performing shift work that does not include night shifts. For the primary analyses, employees not engaged in regular night work.
- Employees not performing regular night work may be included in secondary analyses evaluating workplace-level spillover effects.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Reduced Working Hours (from 38h15minutes to 36h)Reduced Working Hours (from 38h15minutes to 36h) for those conducting night shift work regularly | Other | Reduced working hours (36 h) |
Primary outcome
Sickness Absence Rate
Time frame: From enrollment to the end of treatment at 66 weeks.
Percentage of working time lost due to sickness absence, derived from administrative, payroll-based employer records. No medical or diagnostic information will be collected.
Employee Turnover
Time frame: From enrollment to the end of treatment at 66 weeks.
Termination of employment during the follow-up period, derived from employment records.
Retention of Employees Performing Night Work
Time frame: From enrollment to the end of treatment at 66 weeks.
Proportion of employees performing regular night work who remain employed and performing night shifts during the follow-up period.
Total Weekly Working Hours
Time frame: From enrollment to the end of treatment at 66 weeks.
Average number of paid working hours per week, derived from administrative, payroll-based working-hour records.
Number of Morning, Day, Evening, and Night Shifts
Time frame: From enrollment to the end of treatment at 66 weeks.
Number or rate of shifts worked during each scheduling period, categorized according to shift type (morning, day, evening, and night) using employer payroll-based working-hour records.
13 secondary outcomes
Number of Sickness Absence Episodes
Time frame: From enrollment to the end of treatment at 66 weeks.
Total Sickness Absence Days from Short Episodes (1-5 days) of Sickness Absence
Time frame: From enrollment to the end of treatment at 66 weeks.
Short-Term Sickness Absence Episodes (1-5 Days)
Time frame: From enrollment to the end of treatment at 66 weeks.
Number of Consecutive Shifts
Time frame: From enrollment to the end of treatment at 66 weeks.
Overtime Hours
Time frame: From enrollment to the end of treatment at 66 weeks.
Recovery Periods Between Shifts
Time frame: From enrollment to the end of treatment at 66 weeks.
Number of Quick Returns (<11 Hours Between Shifts)
Time frame: From enrollment to the end of treatment at 66 weeks.
Weekend Work
Time frame: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Recovery
Time frame: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Work-Life Balance
Time frame: From enrollment to the end of treatment at 66 weeks.
Perceived Effects on Workload and Staffing
Time frame: From enrollment to the end of study at 66 weeks.
Implementation Process
Time frame: From enrollment to the end of study at 66 weeks.
Perceived Advantages and Disadvantages of the Intervention
Time frame: From enrollment to the end of study at 66 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Sep 2026.
- Background: PubMed 35365508Voglino G, Savatteri A, Gualano MR, Catozzi D, Rousset S, Boietti E, Bert F, Siliquini R. How the reduction of working hours could influence health outcomes: a systematic review of published studies. BMJ Open. 2022 Apr 1;12(4):e051131. doi: 10.1136/bmjopen-2021-051131.
- Background: PubMed 39836993Turunen J, Karhula K, Ropponen A, Shiri R, Hamalainen K, Ervasti J, Koskinen A, Haavisto O, Sallinen M, Pehkonen J, Harma M. Evaluating quick return restrictions on sickness absence in healthcare employees: A difference-in-differences study. Int J Nurs Stud. 2025 Mar;163:104996. doi: 10.1016/j.ijnurstu.2025.104996. Epub 2025 Jan 10.
- Background: PubMed 32736788Turunen J, Karhula K, Ropponen A, Koskinen A, Hakola T, Puttonen S, Hamalainen K, Pehkonen J, Harma M. The effects of using participatory working time scheduling software on sickness absence: A difference-in-differences study. Int J Nurs Stud. 2020 Dec;112:103716. doi: 10.1016/j.ijnurstu.2020.103716. Epub 2020 Jul 14.
- Background: PubMed 39571045Ropponen A, Hirvonen M, Kuusi T, Harma M. Concurrent Trajectories of Objectively Measured Insufficient Recovery and Workload Among a Cohort of Shift Working Hospital Employees: Quantitative Empirical Research. Nurs Open. 2024 Nov;11(11):e70101. doi: 10.1002/nop2.70101.
- BackgroundNeubert, S., Bader, C., Hanbury, H., & Moser, S. (2022). Free days for future? Longitudinal effects of working time reductions on individual well-being and environmental behaviour. Journal of Environmental Psychology, 82, 101849. https://doi.org/https://doi.org/10.1016/j.jenvp.2022.101849
- Background: PubMed 35805827Krutova O, Koskinen A, Peutere L, Ervasti J, Virtanen M, Harma M, Ropponen A. A Longitudinal Study on Trajectories of Night Work and Sickness Absence among Hospital Employees. Int J Environ Res Public Health. 2022 Jul 3;19(13):8168. doi: 10.3390/ijerph19138168.
- Background: PubMed 27803010Kecklund G, Axelsson J. Health consequences of shift work and insufficient sleep. BMJ. 2016 Nov 1;355:i5210. doi: 10.1136/bmj.i5210.
- Background: PubMed 33656825IARC Working Group on the Identification of Carcinogenic Hazards to Humans. Night Shift Work. Lyon (FR): International Agency for Research on Cancer; 2020. Available from http://www.ncbi.nlm.nih.gov/books/NBK568195/
- Background: PubMed 40958582Harma M, Karhula K, Turunen J, Koskinen A, Shiri R, Sallinen M, Vanttola P, Haavisto O, Hakola T, Ropponen A. Working time traffic light recommendations: development, use, and implementation in the Finnish social and healthcare. Ind Health. 2026 May 20;64(3):214-232. doi: 10.2486/indhealth.2025-0082. Epub 2025 Sep 15.
- Background: PubMed 25788103Harma M, Ropponen A, Hakola T, Koskinen A, Vanttola P, Puttonen S, Sallinen M, Salo P, Oksanen T, Pentti J, Vahtera J, Kivimaki M. Developing register-based measures for assessment of working time patterns for epidemiologic studies. Scand J Work Environ Health. 2015 May 1;41(3):268-79. doi: 10.5271/sjweh.3492. Epub 2015 Mar 19.
- BackgroundHanbury, H., Illien, P., Ming, E., Moser, S., Bader, C., & Neubert, S. (2023). Working less for more? A systematic review of the social, economic, and ecological effects of working time reduction policies in the global North. Sustainability: Science, Practice and Policy, 19(1), 2222595. https://doi.org/10.1080/15487733.2023.2222595
- Individual participant dataSharing planned: No. Individual participant data will not be shared because the study uses employer-owned administrative and payroll-based records containing potentially identifiable employee information. Data sharing is restricted by data protection regulations, data use agreements, and organizational policies of the participating wellbeing services counties.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Reduced Working Hours (from 38h15minutes to 36h) in people with Night Shift Work and Sickness Absence, run by Finnish Institute of Occupational Health at 3 sites in Finland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 30 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Finland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Annina Ropponen, Professor (+358304742012, annina.ropponen@ttl.fi), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Sickness Absence Rate (time frame: From enrollment to the end of treatment at 66 weeks.). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07848607, which also lists 11 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Sep 2026.