Skeletal Effects of Chronic Night Shift (ACORN)

May 13, 2026 updated by: University of Colorado, Denver

Skeletal Effects of Chronic Night Shift (ACORN Study)

The specific aim of this observational study is to characterize changes in bone turnover makers (BTMs), bone mineral density (BMD), and bone microarchitecture in a cohort of nurses during their first year of night compared to day shift work. The hypothesis is that night shift nurses will have poorer bone health indices at one year compared to day shift nurses.

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.

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.
59

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

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • CU Anschutz

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

We will recruit volunteers from the pool of recently graduated new nurse hires at UCH. We will target our recruitment towards units that work the night shift (floor/ICU units) or day shifts (peri-operative and operating room units).

Description

Inclusion Criteria

  • Healthy, nonpregnant adults 20-50 years old who recently (≤6 months) graduated from nursing school and were hired by University of Colorado Hospital for their first nursing position
  • For women to be eligible, they must be premenopausal, not breastfeeding, not pregnant with no plans to become pregnant during the year of observation and willing/able to maintain their current method of contraception use as detailed below.
  • Willing and able to travel to/from CU-AMC for study measurements at baseline and quarterly for one full year

Exclusion Criteria

  • Non-nursing school related shift work 1 year prior to study. (note: many nursing students work as an Advanced Care Partner (ACP) or as a Student Nurse Extern (SNE) and these positions will not be considered exclusionary).
  • Current smokers at baseline (or within the previous year of study).
  • Individuals who are concurrently participating in another research protocol that would influence their safe participation in this study. For example, participants involved in a study that requires blood draws or ingestion of experimental medication as this would increase the risk of participation in our study and/or compromise study results.
  • Any clinically significant unstable medical or surgical condition within the last year (treated or untreated), including history of a clinically significant abnormality of the neurological system (including cognitive disorders or significant head injury) or any history of seizure (including febrile seizure-sleep loss has been used clinically to induce seizures in patients with epilepsy). Given the wide range of illnesses that are encountered in medical practice, it would not be possible to provide a comprehensive list of each and every disease that could serve as grounds for exclusion for the subject. However, the following is a list of illness categories that would certainly be grounds for exclusion: Connective Tissue and Joint Disorders; Neurologic/cognitive Disorders; Musculoskeletal Disorders; Immune Disorders; Chronobiologic Disorders; Cardiovascular Disorders; Respiratory Disorders; Kidney Disorders; Infectious Diseases; Hematopoietic Disorders; Neoplastic Diseases; and Endocrine and Metabolic Diseases.

  • Self-reported or newly diagnosed medical condition that is still being investigated or is not under good control, including those identified on screening labs such as:

    o Out-of-range values measured on a blood sample such as glucose, TSH, creatinine or hemoglobin, that represent clinically significant abnormalities that may jeopardize safe participation or accuracy of outcome measures, at PI discretion

  • Any unstable psychiatric condition including but not limited to schizophrenic disorders and previously diagnosed personality disorders. Individuals with a history of anxiety or depression that has not required inpatient treatment and is well controlled without medication or on a stable medication dose will be permitted at the PI's discretion. Additionally, a personal history of limited prior counseling, psychotherapy (e.g., for adjustment reactions) will NOT be exclusionary.

  • Evaluation of Psychiatric/Psychological Suitability:

    • Inability to demonstrate a full understanding of the requirements and demands of the study.
    • Individuals who are unaware of specific psychiatric diagnoses who have a history of having been treated with antidepressants, neuroleptic medications or major tranquilizers will be excluded from study.
  • Individuals with any clinically significant sleep disorder; Diagnosis or symptoms of sleep disorders (history of significant parasomnia as an adult [night terrors, frequent sleep walking], insomnia, including but not limited to hypersomnias such as apnea, periodic limb movements, narcolepsy). Sleep disorders will be screened by self-report and physician interview including use of validated sleep questionnaires (PSQI, Epworth sleepiness scale, and Berlin sleep questionnaire for sleep apnea).
  • Individuals on medications known to affect bone turnover (e.g., glucocorticoids, osteoporosis medications);
  • Individuals with eGFR < 60 mL/min/1.73m2 as this is known to affect CTX measurements.
  • Symptoms of active illness (e.g., fever) at time of enrollment; note - participant may be studied at a later date if they have not yet started their clinical duties by that time

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.
University of Colorado Health New Nurses (Day Shift Workers)
Day shift work group nurses have greater than 50% of their shifts as day shifts.
University of Colorado Health New Nurses (Night Shift Workers)
Night shift work group nurses have greater than 50% of their shifts as night shifts.

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 change of propeptide of type 1 procollagen (P1NP) over 1 year
Time Frame: From baseline up to 12 months
Difference in change of P1NP over 1 year between the two groups (night vs. day shift nurses), as measured via bone biomarker assays (immunodiagnostic systems, chemiluminescence, immunoassay)
From baseline up to 12 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
Between-group differences in the change in osteocalcin
Time Frame: From baseline up to 12 months
Between-group differences in the change in another bone formation marker (osteocalcin)
From baseline up to 12 months
DXA-derived areal bone mineral density (aBMD) changes
Time Frame: From baseline up to 12 months
Between-group differences in aBMD at the lumber spine, total hip and femoral neck measured by DXA
From baseline up to 12 months
Change in bone microarchitecture
Time Frame: From baseline up to 12 months
Change in trabecular volumetric BMD (vBMD) derived from high-resolution peripheral quantitative computed tomography (HR-pQCT)
From baseline up to 12 months
Between-group differences in the change in CTX (C-telopeptide of type I collagen)
Time Frame: From baseline up to 12 months
Between-group differences in the change in a bone resorption marker (CTX)
From baseline up to 12 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.
University of Colorado, Denver

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Heart, Lung, and Blood Institute (NHLBI)

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: Christine M Swanson, MD, MCR, CU Anschutz

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.
October 27, 2021

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.
February 19, 2026

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.
February 19, 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).
September 29, 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.
October 11, 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.
October 25, 2021

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.
May 15, 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.
May 13, 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.
May 1, 2026

More Information

Terms related to this study

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.
  • 20-3014
  • R01HL151332 (U.S. NIH Grant/Contract)

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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