The Metabolic and Circadian Effects of Shift Work (OPTI-SHIFT)

November 14, 2025 updated by: Tinh-Hai Collet, MD

The Metabolic and Circadian Effects of Shift Work - An Observational Study

In an exploratory observational pilot study, the investigators will focus on the effects of short-term circadian misalignment induced by shift work on multidimensional measurements including glucose excursion, metabolic health, circadian rhythms (measured in vitro and in vivo), sleep/wake cycles and ambient light, eating and activity patterns, well-being and attention.

Study Overview

Status

Status

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

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 (Actual)

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.
72

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 Contact Backup

Study Locations

  • Switzerland
      • Geneva, Switzerland, 1211
        • Geneva University Hospitals

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

20 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Shift workers

Description

Inclusion Criteria:

  • Men and women
  • Age 20-50 years
  • Working ≥ 80% full-time equivalent over the previous month and during the study
  • Working night shifts (i.e. shifts that comprise working hours between 23h and 06h) in rotation with day shifts (i.e. shifts that comprise working hours between 06h and 20h)
  • Planned to work at least 3 consecutive night shifts during the study preceded by at least a day off or day shift
  • Planned to work at least 3 consecutive day shifts during the study
  • Confident use of a smartphone compatible with the study application (iOS, Android) and able to regularly take pictures of consumed food/drinks
  • Able to give a fully informed consent and follow the study procedures

Exclusion Criteria:

  • Planned or current pregnancy during the study
  • Menopausal women
  • Major illness or hospitalization over the previous month
  • Carries a pacemaker, pump or other medical device that can be disabled by a magnet
  • Major mental illness
  • Trip to a different time zone (≥ 2-hour time difference) over the previous month or planned during the study
  • Enrolled in an interventional clinical trial (potentially interfering with the main outcomes) over the previous month or planned during the study

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.
Shift workers
Measurements repeated during a series of day shifts and during a series of night shifts
Other: Exposure to shift work
Detailed questionnaire adapted from the Standard Shiftwork Index, measured at inclusion

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
Difference in glucose excursion
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by Continuous Glucose Monitoring
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months

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
Difference in fasting glucose
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by clinical chemistry (mmol/L)
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in weight
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Body weight (Kg)
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in waist circumference
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Waist circumference (cm) assessed with a measuring tape
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in lipid profile
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol measured by clinical chemistry (mmol/L)
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in blood hormonal profile
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Insulin (mIU/L), thyroid-stimulating hormone (mIU/L), cortisol (nmol/L) measured by clinical chemistry
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in eating duration
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Time from the first to last caloric intake over a 24-hour period
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in nutrient intake
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Total calorie and macronutrient intake over a 24-hour period
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in systolic and diastolic blood pressure
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by blood pressure arm cuff
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in heart rate variability
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by wearable sensor
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in physical activity
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by actigraphy and the International Physical Activity Questionnaire
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in sleep/wake cycles
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by actigraphy
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in sleep quality
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by the Pittsburgh Sleep Quality Index (PSQI), score ranges from 0 to 21 points, 0 indicating no difficulty and 21 severe difficulties
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in attention and sleepiness
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by the Sustained Attention to Response Test
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in well-being
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by the World Health Organization-5 questionnaire (WHO-5), score ranges from 0 to 25, 0 indicating worst possible and 25 best possible
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in mental health outcomes
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by the Patient Health Questionnaire-9 (PHQ-9), score ranges from 0 to 27, 0 indicating no depression and 27 severe depression
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Difference in blood metabolomic parameters
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by high-throughput mass spectrometry metabolomics, semi-quantitative identification of small metabolites involved in carbohydrate, fat, protein, and steroid metabolism
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in lipid metabolism
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by high-throughput mass spectrometry lipidomics
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in the exposure to ambient light
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by wearable spectrometer and the light exposure behaviour assessment (LEBA) questionnaire
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
Difference in the core body temperature
Time Frame: Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months
As measured by a wearable skin temperature and heat transfer sensor
Between a series of day shifts and a series night shifts, separated by an interval from 10 days to 3 months

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.
Tinh-Hai Collet, MD

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Tinh-Hai Collet, MD, Geneva University Hospitals, Geneva

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

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.
February 1, 2022

Primary Completion (Actual)

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.
August 30, 2024

Study Completion (Actual)

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.
August 30, 2024

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).
November 18, 2021

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.
December 15, 2021

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.
January 5, 2022

Study Record Updates

Last Update Posted (Estimated)

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.
November 18, 2025

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.
November 14, 2025

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.
November 1, 2025

More Information

Terms related to this study

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.
  • 2021-01088

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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