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Completed

NCT Number: NCT05177965

The Metabolic and Circadian Effects of Shift Work

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.

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Key information

Conditions

Shift Work Schedule

Age range

20 year–50 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Geneva University Hospitals

Geneva, 1211, Switzerland

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Exposure to shift work

Other

Detailed questionnaire adapted from the Standard Shiftwork Index, measured at inclusion

Primary outcomes

  1. 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

Secondary outcomes

  1. 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)

  2. 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)

  3. 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

  4. 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)

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

Other outcomes

  1. 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

  2. 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

  3. 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

  4. 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

Sponsors and collaborators

Lead sponsor

Tinh-Hai Collet, MD

Other

Registry information

Official study title

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

Acronym: OPTI-SHIFT

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Jan 5, 2022
Registry last updated
Nov 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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