Night shift work and the risk of metabolic syndrome: Findings from an 8-year hospital cohort

• Published in: PloS one 2021-12, Vol.16 (12), p.e0261349-e0261349
• Main Authors: Cheng, Wan-Ju, Liu, Chiu-Shong, Hu, Kai-Chieh, Cheng, Yu-Fang, Karhula, Kati, Härmä, Mikko
• Format: Article
• Language: English
• Subjects: Adult; Biology and Life Sciences; Blood pressure; Blood Pressure - physiology; Cardiovascular disease; Cholesterol; Chronobiology Disorders - etiology; Chronobiology Disorders - physiopathology; Circadian Rhythm - physiology; Circadian rhythms; Cohort Studies; Cross-Sectional Studies; Design; Diabetes; Employees; Fasting; Female; Glucose; Health aspects; High density lipoprotein; Hospitals; Humans; Hypertension; Long-term effects; Longitudinal studies; Male; Medicine and Health Sciences; Metabolic disorders; Metabolic syndrome; Metabolic Syndrome - epidemiology; Metabolic Syndrome - etiology; Metabolic syndrome X; Night shifts; Nighttime; Occupational Diseases - etiology; Occupational health; Occupations; Personnel, Hospital; Regression analysis; Regression models; Risk analysis; Risk Factors; Shift work; Shift Work Schedule - adverse effects; Shift Work Schedule - psychology; Sleep - physiology; Social Sciences; Waist Circumference - physiology; Work hours; Work Schedule Tolerance - physiology; Workers; Working hours
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0261349

Studies concerning the risk of metabolic syndrome associated with night work have shown inconsistent findings, due to imprecise working time data and cross-sectional design. We used register-based daily working time data to examine the risk of incident metabolic syndrome associated with night shift work. Working time data collected between 2010 and 2018 of 5775 Taiwanese hospital workers were used to identify night shift workers and to calculate the number of night shifts. Metabolic syndrome was identified by annual occupational health examination results, which were linked to the working time data. Logistic regression models and generalized estimating equations were used to examine the association between night shift work and metabolic syndrome and the 5 components of metabolic syndrome. Night shift work is associated with a higher risk of developing metabolic syndrome (adjusted OR = 1.36, 95% CI = 1.04 to 1.78) and high waist circumference (adjusted OR = 1.27, 95% CI = 1.07 to 1.78) compared to day work. Among night shift workers, increased number of night shifts was associated with high blood pressure (adjusted OR = 1.15, 95% CI = 1.01 to 1.31). Night shift work is associated with metabolic risk factors. Long-term effects of circadian rhythm disruption on metabolic disturbances needs to be further studied.