Mapping the Shift Worker's Microbiome

January 21, 2026 updated by: Carsten Skarke, MD, University of Pennsylvania
The investigators hypothesize that disruptions to the microbiome of shift-workers represent a hitherto unexamined factor contributing to disease risk. The investigators will therefore define time-of-day dependent fluctuations of the microbiome in night shift workers and matched daytime workers deeply phenotyped for behavioral, clinical, and metabolomic outputs using integrated remote sensing.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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.

Detailed Description

Though several epidemiological studies have demonstrated that working night shift schedules are a risk factor for developing metabolic and cardiovascular diseases, the mechanisms through which this is conferred is not yet understood. Shift-work schedules alter employee's patterns of activity, light exposure and dietary intake in a manner incongruent with the endogenous clock. This circadian clock ensures that our metabolic activity occurs at maximally beneficial times of the day, but is largely unable to adapt to rapidly shifting schedules or sustained night-work. In mice, the investigators' lab has previously shown that genes relevant to all aspects of the metabolic syndrome are subject to circadian oscillation and that the gut microbiome is also subject to control by the host molecular clock. Despite the large contribution of our microbiome to host metabolism, the microbiome has been scarcely studied in the shift-working population. The investigators hypothesize that disruptions to the microbiome of shift-workers represent a hitherto unexamined factor contributing to disease risk. The investigators will therefore define time-of-day dependent fluctuations of the microbiome in night shift workers and matched daytime workers deeply phenotyped for behavioral, clinical, and metabolomic outputs using integrated remote sensing. The investigators will assess core body temperature, sleep/activity cycles, cortisol and melatonin as outputs determined by the host clock, and postprandial glucose and insulin levels as well as nocturnal blood pressure dipping as risk-related outputs. Through antibiotic-induced suppression, The investigators will determine the microbiome's specific contribution to these outputs. This has major implications for refining shift-work schedules and exploring therapeutic strategies in this population.

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.
Interventional

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.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Institute for Translational Medicine and Therapeutics (ITMAT), University of Pennsylvania School of Medicine

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

40 years to 59 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Cohort 1: healthy un-medicated males (to limit gender-induced variability similar to our pilot study), shift-work schedule (>3 shifts per month outside 7am-6pm (9)) for the past ≥10 years, 40-59 years old (increased prevalence of the metabolic syndrome at ≥60 years of age (20));
  • Cohort 2: day workers who work 7am-6pm for ≥10 years matched for line of work, age, gender, and BMI;
  • Volunteers are capable of giving informed consent;
  • 40-59 years of age;
  • Own an android smartphone which installs the remote sensing applications (those with apple smartphones will not be recruited);
  • Non-smoking;
  • Male subjects
  • The use of contraception will NOT be required for male participants.

Exclusion Criteria:

  • Recent travel across more than two (2) time zones (within the past month);
  • Planned travel across more than two (2) time zones during the planned study activities;
  • Use of illicit drugs;
  • High dose vitamins (Vitamin A, Vitamin C, Vitamin E, Beta Carotene, Folic Acid and Selenium), alcohol and any over-the counter NSAID in the (2) two weeks before the start of the 48 hour deep phenotyping;
  • High fat foods and caffeine in the past 24 hours prior to the 48-hour deep chronotyping session;
  • History of abdominal surgery;
  • Known allergy or intolerance to Vancomycin, and/or Neomycin;
  • Use of anticholinergics in the week prior to the 48-hour sessions;
  • Use of laxatives or anti-diarrhea medications in the two weeks prior to the 48-hour sessions;
  • Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening;
  • Subjects with any abnormal laboratory value or physical finding that according to the investigator may interfere with interpretation of the study results, be indicative of an underlying disease state, or compromise the safety of a potential subject;

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

  • Primary Purpose: Other
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Experimental: Cohort 1
Shift workers receive a standardized meal with a glucose challenge test
Other: Standardized meal with a glucose challenge test
Postprandial glucose and insulin response
Experimental: Cohort 2
Matched healthy controls receive a standardized meal with a glucose challenge test
Other: Standardized meal with a glucose challenge test
Postprandial glucose and insulin response

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
Area under the glucose over time curve
Time Frame: 12 hour
Area under the curve (AUC) will be calculated from serial, timed glucose measurements
12 hour

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
Time-of-day dependent fluctuations of the microbiome
Time Frame: 48 hours
Relative abundances assessed several times of day (morning, afternoon, evening, night with target times of 08:00, 14:00, 20:00, 02:00 +/- 1 hour)
48 hours
Compound outcome derived from percent variance explained in communication (number of phone calls and text messages), mobility (miles traveled), light exposure, blood pressure, heart rate, heart rate variability, sleep/wake times, body core temperature
Time Frame: 48 hours
To evaluate the linear relationships between every pairwise combination of variables in the integrated dataset, the R^2, or coefficient of determination, will be calculated for each pair using linear regression. A heat map of the proportion of variance in each variable (e.g. mobility, light exposure, systolic blood pressure) explained by each other variable will then be constructed to allow an integrative exploration of these data. Here, the advantage is that multiple assessments with different units of measure can be integrated to generate deep phenotypes.
48 hours
Compound outcome derived from variance observed in multiomics outputs (metabolites, microbiota).
Time Frame: 48 hours
To explore factors contributing to the variance observed using principal components analysis
48 hours

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.
University of Pennsylvania

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: Carsten Skarke, MD, University of Pennsylvania

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.
September 27, 2017

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.
January 1, 2028

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.
November 1, 2028

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).
December 21, 2016

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 14, 2017

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 18, 2017

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.
January 23, 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.
January 21, 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.
January 1, 2026

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.
  • 826117

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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