Association of night shift work and related risk factors with overweight and obesity across Europe: the SHIFT2HEALTH Online Survey.

INTRODUCTION

Night shift work is associated with higher risk of overweight/obesity (OW/OB). This study examines the prevalence of OW/OB among current and former night shift workers, compared to day workers, across Europe, and assesses the influence of night shift metrics and lifestyle/psychosocial factors on this relationship.

METHODS

Data on participants' self-reported BMI, night shift metrics, sociodemographics, and lifestyle/psychosocial factors were collected via an online survey in Austria, Denmark, Germany, Greece, Italy, the Netherlands, Poland, and Spain (May 2024-January 2025). Logistic regression models analysed the associations between night shift work metrics, lifestyle/psychosocial factors, and OW/OB, accounting for additional adjustments.

RESULTS

Among 6,148 Europeans [mean age: 40.6 (10.6) years; 50% female], OW/OB prevalence was highest in Germany and lowest in Denmark (61% vs. 41%; p<0.001). Current and former night shift workers exhibited higher prevalence of obesity (OR 1.62, 95%CI: 1.33-1.99; OR 1.51 95%CI: 1.19-1.93) than day workers. Longer, more frequent, and rotating night shift exposure correlated with higher odds of OW/OB. Among current night shift workers, factors such as fast eating rate, physical inactivity, and moderate/high alcohol consumption influenced OW/OB prevalence, with unfavourable dietary patterns linked to OB. Adjustments for lifestyle/psychosocial factors had minimal impact on these outcomes.

CONCLUSION

Current and former night shift workers exhibited a higher prevalence of OW/OB than day workers. Lifestyle factors, especially eating rate and physical activity, partly explain this elevated risk. Therefore, prevention strategies could benefit from combining organizational, environmental, and workplace interventions, particularly since an elevated BMI may persist even after night shift work has ceased.