Circadian Rhythm and Health in Heavy Industry Shift Workers

July 9, 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

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Estimated)

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 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

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
Intervention / Treatment
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

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). Higher scores indicate a greater preference for morningness, whereas lower scores indicate a greater preference for eveningness.
At enrollment (single assessment)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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. Higher scores indicate greater musculoskeletal discomfort.
At enrollment (single assessment)
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)
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 physical, psychological, social, and environmental domains. Higher domain scores indicate 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

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)

July 20, 2026

Primary Completion (Estimated)

September 20, 2026

Study Completion (Estimated)

September 30, 2026

Study Registration Dates

First Submitted

July 9, 2026

First Submitted That Met QC Criteria

July 9, 2026

First Posted (Actual)

July 14, 2026

Study Record Updates

Last Update Posted (Actual)

July 14, 2026

Last Update Submitted That Met QC Criteria

July 9, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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