OsteoporosisACORNNCT05091021
Skeletal Effects of Chronic Night Shift
An observational study of Osteoporosis and Circadian Rhythm Sleep Disorder, Shift Work Type, run by University of Colorado, Denver at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 20 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Osteoporosis, Circadian Rhythm Sleep Disorder, Shift Work Type
- How many people
- 59 participants
- Where
- 1 siteUnited States
- Study dates
- 27 Oct 2021to 19 Feb 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
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).
Who may be able to join
- 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
Who cannot join
- 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
Show all 14Show fewer
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
- Medical subject headings
- Osteoporosis, Sleep Disorders, Circadian Rhythm
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| 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 being measured
The primary outcome is the main question the study is designed to answer.
Difference in change of propeptide of type 1 procollagen (P1NP) over 1 year
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)
Measured: From baseline up to 12 months
Secondary outcomes (4)
Between-group differences in the change in osteocalcin
Between-group differences in the change in another bone formation marker (osteocalcin)
Measured: From baseline up to 12 months
DXA-derived areal bone mineral density (aBMD) changes
Between-group differences in aBMD at the lumber spine, total hip and femoral neck measured by DXA
Measured: From baseline up to 12 months
Change in bone microarchitecture
Change in trabecular volumetric BMD (vBMD) derived from high-resolution peripheral quantitative computed tomography (HR-pQCT)
Measured: From baseline up to 12 months
Between-group differences in the change in CTX (C-telopeptide of type I collagen)
Between-group differences in the change in a bone resorption marker (CTX)
Measured: From baseline up to 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Oct 2021
- Study start27 Oct 2021
- Primary completion19 Feb 2026
- Study completion19 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for OsteoporosisStudies of the same condition, open and under way.
- More trials run by University of Colorado, DenverThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 59 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Denver
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Responsible party
- Sponsor
- Investigators
- Christine M Swanson, MD, MCR, Principal investigator, CU Anschutz
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05091021
- Sponsor's protocol ID
- 20-3014
- Other IDs
- R01HL151332
- Acronym
- ACORN
- Status last verified
- May 2026
- First submitted
- 29 Sep 2021
- Last updated
- 15 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Skeletal Effects of Chronic Night Shift (ACORN Study)
- ClinicalTrials.gov ID
- NCT05091021
- Acronym / sponsor ID
- ACORN / 20-3014
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 59 participants (actual)
- Lead sponsor
- University of Colorado, DenverUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- 27 Oct 2021 (actual)
- Primary completion
- 19 Feb 2026 (actual)
- Study completion
- 19 Feb 2026 (actual)
- First posted
- 25 Oct 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 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. |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- 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).
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (14 listed)
- 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:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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)
4 secondary outcomes
Between-group differences in the change in osteocalcin
Time frame: From baseline up to 12 months
DXA-derived areal bone mineral density (aBMD) changes
Time frame: From baseline up to 12 months
Change in bone microarchitecture
Time frame: 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
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Christine M Swanson, MD, MCR principal investigator
CU Anschutz
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Osteoporosis and Circadian Rhythm Sleep Disorder, Shift Work Type, run by University of Colorado, Denver at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in change of propeptide of type 1 procollagen (P1NP) over 1 year (time frame: From baseline up to 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2026.