Rotating Shift-Work as an Independent Risk Factor for Overweight Italian Workers: A Cross-Sectional Study

BACKGROUND A job-related factor is attracting a growing interest as a possible determinant of body weight gain in shift-workers. OBJECTIVE The aim of the study was to reinvestigate the issue of overweight between rotating shift workers and daytime workers, taking into consideration possible confounding covariate factors. METHODS This is a cross-sectional study, conducted by reviewing data from subjects participating in an occupational surveillance program in 2008. Participants answered a self-administered questionnaire to retrieve information about socio-demographic factors and working conditions (job schedule type, job-related physical activity, time in job), subjective health status, health care visits during the previous year, and lifestyle factors (dietary habits, leisure time physical activity, alcohol consumption). Participants underwent a medical examination for measurement of BMI, and acquisition of medical history. RESULTS Compared to daytime workers (N = 229), rotating shift workers (N = 110) displayed higher BMI (mean BMI was 27.6±3.9 and 26.7±3.6 for shift workers, and daytime workers, respectively; p<0.05). Logistic regression analysis allowed to highlight the role of rotating shift-work as an independent risk factor for increased body weight (OR 1.93, 95%CI 1.01-3.71), being aged between 35 and 54 years was a major determinant of increased BMI (OR 2.39, 95%CI 1.14-5.00). In addition, family history of obesity was the strongest determinant of overweight/obesity (OR 9.79, 95%CI 1.28-74.74). Interestingly, no significant association was found between overweight and other potentially relevant factors, such as diet quality and food choices, alcohol consumption, levels of occupational and leisure-time physical activity. CONCLUSIONS Present findings seem to support the notion that rotating shift work is an independent risk factor for overweight, regardless of workers' dietary habits and physical activity levels.