8263460 Effect of shift work on blood pressure and markers of obesity in the EPHOR-NIGHT WORK study

<h3>Objective</h3> Shift work, particularly night shifts, have been linked to poor cardiometabolic outcomes. However, the mechanistic pathways underlying these associations are not completely understood. We aimed to evaluate the effect of night shift work on blood pressure and markers of obesity in workers from Spain, Sweden, and Denmark. <h3>Material and Methods</h3> A total of 860 participants aged 21-67 years (mean age 42.6) were included from the EPHOR-NIGHT study, comprising 363 day shift workers and 497 nightshift workers, primarily employed in the healthcare sector. Participants completed a baseline questionnaire and systolic (SBP), diastolic blood pressure (DBP), along with anthropometric parameters were measured by trained personnel. Linear and logistic regression models, adjusting for sociodemographic and lifestyle factors, were used to assess associations between night shift work and blood pressure, hypertension (≥140/90 mmHg), as well as body mass index (BMI), waist circumference, waist–hip ratio, overweight, and abdominal obesity using WHO definitions. <h3>Results</h3> Compared to day workers, night shift work was associated with a 2.85-mmHg increase (95% confidence interval (CI): 0.50-5.19) in SBP and possibly with DBP (β=1.12; 95% CI: -0.53-2.77 mmHg). We observed a higher odds ratio for hypertension (OR=1.59; 95% CI: 1.06-2.38). We also observed a dose-response pattern of hypertension risk per night shifts worked on consecutive days (p for trend 0.03). Night shift work was also associated with higher BMI (β=0.88; 95% CI: 0.09-1.68), and potentially with overweight (OR=1.14; 95% CI: 0.81-1.62) or abdominal obesity (OR=1.30; 95% CI: 0.87-1.94). <h3>Conclusion</h3> We found that compared with day workers, night shift work was associated with elevated blood pressure and BMI, two important cardiometabolic risk factors.