Circadian Rhythm and Health in Heavy Industry Shift Workers

July 20, 2026 updated by: Amine Ataç, Istanbul Gedik University

Investigation of Circadian Rhythm, Musculoskeletal Pain, Sleep Quality, and Quality of Life Among Heavy Industry Shift Workers: A Cross-Sectional Study

Shift work can disrupt the body's circadian rhythm, which may negatively affect sleep, musculoskeletal health, and quality of life. Heavy industry workers who perform rotating or night shifts may be particularly vulnerable to these health problems. This cross-sectional observational study will evaluate circadian rhythm characteristics, musculoskeletal pain, sleep quality, and quality of life among heavy industry shift workers. Participants will complete validated questionnaires assessing chronotype, musculoskeletal symptoms, sleep quality, and quality of life. The study will examine the associations between chronotype and these health outcomes and compare the results across different chronotype groups. The findings may contribute to a better understanding of the health effects of shift work and support the development of occupational health strategies for shift workers

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
220

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

N/A

Sampling Method

Non-Probability Sample

Study Population

Shift workers: Heavy industry workers employed in a shift work system will be recruited from participating industrial workplaces in İstanbul, Kocaeli in Türkiye. Eligible participants will be adults aged 18 to 65 years who have been working in a rotating or night shift schedule for at least 3 months and are willing to participate in the study.

Description

Inclusion Criteria:

  • Ages 18-65
  • Working in a shift system for at least 3 months
  • Agreeing to participate in the work voluntarily
  • Being a shift worker

Exclusion Criteria:

  • Presence of using any medication that may affect alertness or muscle activity

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Heavy Industry Shift Workers
Heavy industry workers who perform shift work and will undergo a single questionnaire-based assessment.
Other: Questionnaire-Based Assessment
Participants will complete validated self-administered questionnaires to assess chronotype, musculoskeletal pain, sleep quality, and quality of life. No therapeutic intervention will be administered.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Morningness-Eveningness Questionnaire (MEQ)
Time Frame: At enrollment (single assessment)
The Morningness-Eveningness Questionnaire (MEQ) is a validated 19-item self-administered questionnaire used to determine an individual's chronotype (morning, intermediate, or evening type). Total scores range from 16 to 86. Higher scores indicate a greater preference for morningness, whereas lower scores indicate a greater preference for eveningness.
At enrollment (single assessment)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Pittsburgh Sleep Quality Index (PSQI)
Time Frame: At enrollment (single assessment)
The Pittsburgh Sleep Quality Index (PSQI) is a validated self-administered questionnaire used to evaluate sleep quality over the previous month. Total scores range from 0 to 21, with higher scores indicating poorer sleep quality.
At enrollment (single assessment)
Cornell Musculoskeletal Discomfort Questionnaire (CMDQ)
Time Frame: At enrollment (single assessment)
The Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) is a validated self-administered questionnaire used to assess the frequency, severity, and work-related impact of musculoskeletal discomfort in different body regions. The total score is calculated by summing weighted scores across body regions and does not have a fixed minimum or maximum value. Higher scores indicate greater musculoskeletal discomfort.
At enrollment (single assessment)
World Health Organization Quality of Life-BREF (WHOQOL-BREF)
Time Frame: At enrollment (single assessment)
The World Health Organization Quality of Life-BREF (WHOQOL-BREF) is a validated self-administered questionnaire that assesses quality of life across the physical, psychological, social, and environmental domains. Domain scores are transformed to a 0-100 scale, with higher scores indicating better quality of life.
At enrollment (single assessment)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Istanbul Gedik University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 20, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 20, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 9, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 9, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 14, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • E-10840098-50.04-3312

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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