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NCT Number: NCT05984979

The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and Diabetes

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.

Recruiting

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Key information

Conditions

Diabetes Mellitus Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Bern

Bern, 3010, Switzerland

Location status: Recruiting

Location contact

Nicolier Cléo

SUB_INVESTIGATOR

Witthauer Lilian, Prof.Dr.

CONTACT

[email protected]

+41 31 664 22 77

Witthauer Lilian, Prof.Dr.

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Subgroup 1:

  • Age 18 or older
  • HbA1c below 6.5%
  • Written informed consent

Subgroup 2:

  • Age 18 or older
  • 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

Exclusion criteria

  • 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)
  • Drinking habit of more than four units of alcohol per day
  • Current inhaled medicines treatments
  • Antibiotic treatment in the previous 4 months

Treatment and study plan

Standardized meal

Other

The participants will receive a standardized meal for breakfast

Primary outcomes

  1. 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.

  2. VOC Patterns over time as boxplots

    Time frame: During the study procedure (approximately 8 hours)

    Box plots from selected VOC peaks over time.

Secondary outcomes

  1. Capillary blood glucose

    Time frame: During the study procedure (approximately 8 hours)

    Correlation between capillary blood glucose and VOCs

  2. Correlation between VOCs in breath intestinal microbiota

    Time frame: day 1

    Correlation between VOCs in breath and intestinal microbiota species abundance

  3. Correlation between VOCs in breath oral microbiota

    Time frame: day 1

    Correlation between VOCs in breath and oral microbiota species abundance

  4. Correlation between VOCs and subgroups

    Time frame: day 1 or 8 hours

    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

Study contacts

Contact information is provided by the study sponsor or research team.

Lilian Witthauer

CONTACT

[email protected]

+41 31 664 22 77

Sponsors and collaborators

Lead sponsor

University of Bern

Other

Collaborators

  • DCB Research AG
  • Insel Gruppe AG, University Hospital Bern

Registry information

Official study title

The Daytime Circadian Rhythm in Exhaled Volatile Organic Compounds in People Living Without and With Type 1 and 2 Diabetes: an Exploratory Study

Acronym: VOCircle

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Aug 9, 2023
Registry last updated
Dec 8, 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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