Rotating shift work time is directly associated with excess body adiposity

Objective: To analyze the association between changes in body adiposity and length of service on a schedule of rotating shifts.

Methods: The study was a cross-sectional investigation conducted during the years 2012, 2015, and 2018, involving individuals engaged in rotating shifts at a company involved in iron ore extraction situated within the Iron Quadrangle region of Minas Gerais and the southeastern region of Pará, Brazil. Sociodemographic and behavioral data were collected along with anthropometric parameters in order to calculate body mass index (BMI) and the waist-to-height ratio (WHtR). For data analysis, a multivariate logistic regression was employed to explore potential associations between indicators of body adiposity and the duration of shift work, employing a hierarchical determination model.

Results: The findings showed that in the multivariate model, controlling for confounding factors, workers with 5 to 10, 10 to 15, and more than 15 years of shift work had 41 to 96% greater odds of being overweight (BMI > 25.0 kg/m²), 71 to 82% of having altered neck circumference (> 40 cm), 33 to 120% of altered WC (>102 cm), and 57 to 214% of having altered WHtR (> 0.5 cm).

Conclusion: The findings suggest that time spent in work has a significant effect on anthropometric indicators of body adiposity, especially if the worker has a previously established comorbidity such as dyslipidemia or hypertension and is frequently exposed to night work.