Diabetes MellitusVOCircleNCT05984979
The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and Diabetes
An observational study of Diabetes Mellitus, run by University of Bern at 1 site in Switzerland.
Trial summary
Exhaled volatile organic compounds will be measured during daytime with the goal to identifying circadian variability. The study incudes three subgroups: people without diabetes, people with type 1 diabetes, and people with type 2 diabetes. A total of 60 people will be recruited for the study. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Diabetes Mellitus
- What is being tested?
- Standardized meal
- How many people
- 60 participants
- Where
- 1 siteSwitzerland
- Study dates
- 7 Aug 2023to 30 Jun 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: 60 participants with the following subgroups: Subgroup 1: People without diabetes Subgroup 2: People diagnosed with T1D Subgroup 3: People diagnosed with T2D
Who may be able to join
- Subgroup 1:
- Age 18 or older
- HbA1c below 6.5%
- Written informed consent
- Subgroup 2:
- Age 18 or older
Show all 12Show fewer
- T1D (Type 1 diabetes) with MDI (multiple daily injection) or CSII (Continuous subcutaneous insulin infusion therapy) therapy >1 year
- Written informed consent
- Subgroup 3
- Age 18 or older
- T2D (Type 2 diabetes) with oral antidiabetic medication or insulin therapy
- Written informed consent
Who cannot join
- Pregnancy or breastfeeding
- Smoking (last cigarette less than 6 months ago)
- Any chronical lung and intestinal disease diagnosis (such as intestinal bowel disease (IBD); asthma; COPD (chronic obstructive pulmonary disease); lung cancer, …)
- Coeliac disease
- Lactose and fructose intolerance
- Any acute disease diagnosis (such as viral or bacterial infection)
Show all 9Show fewer
- Drinking habit of more than four units of alcohol per day
- Current inhaled medicines treatments
- Antibiotic treatment in the previous 4 months
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site, 1 recruiting
- Recruiting
University of Bern
Bern, 3010
Witthauer Lilian, Prof.Dr., +41 31 664 22 77, lilian.witthauer@unibe.ch
Witthauer Lilian, Prof.Dr.
About this study
Official title: The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and With Type 1 and 2 Diabetes: an Exploratory Study
Exhaled volatile organic compounds will be measured during daytime with the goal to identifying circadian variability. The study incudes three subgroups: people without diabetes, people with type 1 diabetes, and people with type 2 diabetes. A total of 60 people will be recruited for the study.
- Conditions
- Diabetes Mellitus
- Being tested
- Standardized meal
- Medical subject headings
- Diabetes Mellitus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Standardized mealOther
The participants will receive a standardized meal for breakfast
| Study group | Role | What they receive |
|---|---|---|
| People without diabetes | Not described Receives: Other: Standardized meal | |
| People with type 1 diabetes | Not described Receives: Other: Standardized meal | |
| People with type 2 diabetes | Not described Receives: Other: Standardized meal |
What is being measured
The primary outcome is the main question the study is designed to answer.
VOC Patterns over time as gallery plots
Gallery plots (3D visualization of retention index, drift time, ion current) from selected VOC peaks over time.
Measured: During the study procedure (approximately 8 hours)
VOC Patterns over time as boxplots
Box plots from selected VOC peaks over time.
Measured: During the study procedure (approximately 8 hours)
Secondary outcomes (4)
Capillary blood glucose
Correlation between capillary blood glucose and VOCs
Measured: During the study procedure (approximately 8 hours)
Correlation between VOCs in breath intestinal microbiota
Correlation between VOCs in breath and intestinal microbiota species abundance
Measured: day 1
Correlation between VOCs in breath oral microbiota
Correlation between VOCs in breath and oral microbiota species abundance
Measured: day 1
Correlation between VOCs and subgroups
Wilcoxon signed-rank test will be used to explore if the patterns in VOCs differ between subgroup: people without diabetes, people living with T1D, and people living with T2D
Measured: day 1 or 8 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Aug 2023
- Study start7 Aug 2023
- Primary completion30 Jun 2026 (estimated)
- Study completion30 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Diabetes MellitusStudies of the same condition, open and under way.
- More trials run by University of BernThe 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
- Other
- Time perspective
- Other
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Bern
- Sponsor type
- University, hospital or other
- Collaborators
- Insel Gruppe AG, University Hospital Bern, DCB Research AG
- Responsible party
- Sponsor
- Investigators
- Lilian Witthauer, Prof.Dr., Principal investigator, University of Bern
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05984979
- Sponsor's protocol ID
- VOCircle
- Acronym
- VOCircle
- Status last verified
- Dec 2025
- First submitted
- 24 Jul 2023
- Last updated
- 8 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Nicolier C, Rothenbuhler M, Balmer ML, Witthauer L. Daytime circadian patterns of exhaled volatile organic compounds in adults without and with type 1 and type 2 diabetes: protocol for an exploratory observational study. BMJ Open. 2026 Apr 8;16(4):e113892. doi: 10.1136/bmjopen-2025-113892.
PubMed 41951262
Study at a glance
From the registry record, last updated by the sponsor on 8 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and With Type 1 and 2 Diabetes: an Exploratory Study
- ClinicalTrials.gov ID
- NCT05984979
- Acronym / sponsor ID
- VOCircle / VOCircle
- Conditions
- Diabetes Mellitus
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- University of BernUniversity, hospital or other
- Collaborators
- Insel Gruppe AG, University Hospital Bern, DCB Research AG
- Study start
- 7 Aug 2023 (actual)
- Primary completion
- 30 Jun 2026 (estimated)
- Study completion
- 30 Jun 2026 (estimated)
- First posted
- 9 Aug 2023 (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.
Exhaled volatile organic compounds will be measured during daytime with the goal to identifying circadian variability. The study incudes three subgroups: people without diabetes, people with type 1 diabetes, and people with type 2 diabetes. A total of 60 people will be recruited for the study.
Study design
- Observational model
- Other
- Time perspective
- Other
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| People without diabetes | – | Other: Standardized meal |
| People with type 1 diabetes | – | Other: Standardized meal |
| People with type 2 diabetes | – | Other: Standardized meal |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- 60 participants with the following subgroups: Subgroup 1: People without diabetes Subgroup 2: People diagnosed with T1D Subgroup 3: People diagnosed with T2D
Key inclusion criteria (12 listed)
- Age 18 or older
- HbA1c below 6.5%
- Written informed consent
- Age 18 or older
- T1D (Type 1 diabetes) with MDI (multiple daily injection) or CSII (Continuous subcutaneous insulin infusion therapy) therapy >1 year
Key exclusion criteria (9 listed)
- Pregnancy or breastfeeding
- Smoking (last cigarette less than 6 months ago)
- Any chronical lung and intestinal disease diagnosis (such as intestinal bowel disease (IBD); asthma; COPD (chronic obstructive pulmonary disease); lung cancer, …)
- Coeliac disease
- Lactose and fructose intolerance
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Standardized mealThe participants will receive a standardized meal for breakfast | Other | People with type 1 diabetes, People with type 2 diabetes, People without diabetes |
Primary outcome
VOC Patterns over time as gallery plots
Time frame: During the study procedure (approximately 8 hours)
Gallery plots (3D visualization of retention index, drift time, ion current) from selected VOC peaks over time.
VOC Patterns over time as boxplots
Time frame: During the study procedure (approximately 8 hours)
Box plots from selected VOC peaks over time.
4 secondary outcomes
Capillary blood glucose
Time frame: During the study procedure (approximately 8 hours)
Correlation between VOCs in breath intestinal microbiota
Time frame: day 1
Correlation between VOCs in breath oral microbiota
Time frame: day 1
Correlation between VOCs and subgroups
Time frame: day 1 or 8 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Dec 2025.
- Derived from this study: PubMed 41951262Nicolier C, Rothenbuhler M, Balmer ML, Witthauer L. Daytime circadian patterns of exhaled volatile organic compounds in adults without and with type 1 and type 2 diabetes: protocol for an exploratory observational study. BMJ Open. 2026 Apr 8;16(4):e113892. doi: 10.1136/bmjopen-2025-113892.
- 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.
Lilian Witthauer, Prof.Dr. principal investigator
University of Bern
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 Diabetes Mellitus, run by University of Bern at 1 site in Switzerland.
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 12 inclusion and 9 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: looking for participants now, as of the sponsor's last update on 8 Dec 2025. 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 Switzerland. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Lilian Witthauer (+41 31 664 22 77, lilian.witthauer@unibe.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
VOC Patterns over time as gallery plots (time frame: During the study procedure (approximately 8 hours)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05984979, which also lists 1 linked publication.
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 8 Dec 2025.