WP 2

WP2 is closely linked to WP1 through a cross-sectional study (registered on ClinicalTrials.gov) across Austria, Denmark, Germany, the Netherlands, and Poland. Approximately 900 rotating night shift workers and day workers from the healthcare sector and various other industries were recruited between May 2024 and December 2026.

Participants completed online questionnaires and recorded their dietary habits in a mobile app. 
Assessments included body composition, dietary behavior, and sensory preferences. 
Biological samples like blood, urine, saliva, hair, and faeces were collected.

Within the nested mechanistic study, shift workers from Austria and the Netherlands provided additional biological samples (dried blood spots, 24-hour urine and saliva) during both day and night shifts.

Further steps:

A wide range of biomarkers will be analyzed, including hormones, markers of cellular immunity and inflammation, indicators of gut health, and measures related to fat and glucose metabolism, appetite regulation, oxidative stress, metabolomics, and microbiota composition.

We hypothesize that, compared to day workers, night shift workers will exhibit more disrupted levels of early markers associated with obesity. Greater circadian misalignment, sleep disruption, and irregular eating patterns are expected to correlate with more adverse biomarker profiles. Among rotating shift workers, night shifts are anticipated to be associated with acute disruptions in melatonin production, metabolomic profiles, and the composition of oral microbiota compared to day shifts.