An observational study in Obesity, Shift-work Disorder and Circadian Rhythm Disorders, sponsored by University of Vienna. Recruiting at 1 site in Austria. Open to participants aged 21 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-08.
Sponsored by University of Vienna · Observational
Shift work is a well-known risk factor for the development of overweight and obesity, which may lead to downstream effects such as increased risk of cardiometabolic diseases and cancer. However, the biological and behavioral mechanisms underlying the obesogenicity of night shift work are not well understood. Population-based mechanistic studies in real life shift workers are needed to address how night shift work impacts metabolic health.
The investigators aim to characterize the behavioural, environmental, and biological mechanisms and pathways for the association of night shift work and obesity across Europe.
The investigators will conduct a cross sectional study in 5 European countries (Austria, Denmark, Germany, Netherlands and Poland) and recruit 1000 rotating night shift workers and day workers (200/country) from the health sector and different industries. Night and day workers will be age-frequency (3 age groups), gender and (where possible) working tasks matched. Participants will complete online questionnaires and report their diet habits in a mobile app. Body composition, dietary behavior and sensory preferences will be tested. Biologic specimens (blood, urine, saliva, hair and feces) will be collected at the workplace on a day where participants are working on a day shift (or a day off). In a subsample (Austria and Netherlands) shift workers will provide biological samples (spot blood, urine and saliva) both on a day shift and on a night shift. Biomarkers including hormones, cellular immunity and inflammation, parameters linked to gut health and metabolism of fat and sugar, appetite, oxidative stress, metabolomics and microbiota will be measured. The investigators hypothesize that compared to day workers, night shift workers will experience disrupted levels of pre-obesity markers. Higher circadian disruption, sleep disruption and mistimed eating patterns workers will be associated with more disrupted biomarker profiles. Among rotating shift workers, night shift will be associated with acute disrupted melatonin production, metabolomic profiles and composition of oral microbiota compared to a day shift.
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
This study's planned enrollment of 1,000 is above the median of 114 across 2,154 observational studies indexed under Obesity.
Browse Obesity studies →University of Vienna is the lead sponsor of 49 studies on the registry; 16 are open to participants now.
Counted across the registry records on this site, refreshed daily.
We are recruiting shift worker and day worker in the industrial and healthcare setting.
Inclusion Criteria shift worker
Inclusion criteria controls
Exclusion Criteria shift worker and controls:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Nightshift worker in the health care and industrial sector. Night shift is defined as a work schedule that involves working at least 3 hours between 00:00 and 5:00, at least 2 consecutive nights/month.
Other: No intervention
Dayshift worker in the health care and industrial sector. No night shifts.
Other: No intervention
No intervention
high-sensitive C-Reactive Protein (hs-CRP)
Compare hs-CRP levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of hormones in plasma
Compare melatonin levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of hormones in plasma
Compare cortisol levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of parameters linked to gut health in serum and in feces
Compare Short-chain fatty acids (SCFA) levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of parameters linked to gut health in serum and in feces
Compare Fatty acid-binding protein (FABP) levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of parameters linked to gut health in serum and in feces
Compare lipopolysaccharide(LPS)-binding protein levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of parameters linked to gut health in serum and in feces
Compare zonulin-1 levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of cellular immunity and inflammation in plasma
Compare growth factors levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of cellular immunity and inflammation in plasma
Compare cytokines levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of cellular immunity and inflammation in plasma
Compare chemokines levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of metabolism of fat and sugar in plasma
Compare total cholesterol levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of metabolism of fat and sugar in plasma
Compare LDL-C levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of metabolism of fat and sugar in plasma
Compare HDL-C levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of metabolism of fat and sugar in plasma
Compare triglycerides levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider parameters of metabolism of fat and sugar in plasma
Compare glucose levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of appetite markers in plasma
Compare leptin levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of appetite markers in plasma
Compare ghrelin levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of oxidative stress in whole blood, serum, plasma and urine
Compare DNA damage levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of oxidative stress in whole blood, serum, plasma and urine
Compare Malondialdehyde (MDA) levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of oxidative stress in whole blood, serum, plasma and urine
Compare 8-oxo-Guo/Gua levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of oxidative stress in whole blood, serum, plasma and urine
Compare protein carbonyls levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider levels of oxidative stress in whole blood, serum, plasma and urine
Compare unconjugated bilirubin levels between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider metabolomics analysis of plasma samples and dry blood spots (DBS)
Compare the levels of various metabolites between night shift workers and day shift workers
Time frame: Baseline
The investigators will consider microbiome analysis of feces samples and tongue swabs
Compare the levels of various microbiota composition between night shift workers and day shift workers
Time frame: Baseline
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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University of Vienna