Night and shift work and incidence of cerebrovascular disease - a prospective cohort study of healthcare employees in Stockholm

• Published in: Scandinavian journal of work, environment & health Vol. 48; no. 1; pp. 31 - 40
• Main Authors: Bigert, Carolina, Kader, Manzur, Andersson, Tomas, Selander, Jenny, Bodin, Theo, Gustavsson, Per, Härmä, Mikko, Ljungman, Petter, Albin, Maria
• Format: Journal Article
• Language: English
• Published: Finland Scandinavian Journal of Work, Environment & Health 01.01.2022; Nordic Association of Occupational Safety and Health; Nordic Association of Occupational Safety and Health (NOROSH)
• Subjects: cerebrovascular disease; Cerebrovascular diseases; Cerebrovascular Disorders - epidemiology; Cohort analysis; Cohort Studies; Confidence intervals; Delivery of Health Care; Employees; Employment; Female; healthcare; Humans; Incidence; Male; Medicin och hälsovetenskap; Men; Mortality; Night shifts; night work; Nighttime; Nurses; Nursing; occupational exposure; occupational health; Original; Personnel, Hospital; prospective cohort study; Prospective Studies; Risk Factors; Shift work; Shift Work Schedule - adverse effects; shift worker; Sleep deprivation; Statistical models; stockholm; stroke; sweden; Work Schedule Tolerance; Working conditions; Working hours; Sweden
• ISSN: 0355-3140; 1795-990X; 1795-990X
• DOI: 10.5271/sjweh.3986

This study aimed to investigate the effects of various aspects of night and shift work regarding incident cerebrovascular disease (CeVD). The cohort included 26 667 women and 3793 men (nurses and nursing assistants) who were employed for at least one year 2008-2016 in Region Stockholm, Sweden. Information about the cohort and working hours were obtained from a computerized employee-register and diagnoses were retrieved from national and regional registers. We used discrete time proportional hazard models to assess the risk of CeVD (2009-2017), in relation to work hour characteristics, adjusting for sex, age, country of birth, education and profession. We observed an excess risk of CeVD (N=223) among employees who, during the preceding year, worked night shifts >30 times [hazard ratio (HR) 1.44, 95% confidence interval (CI) 1.04-1.99] or ≥3 consecutive night shifts >15 times (HR 1.69, 95% CI 1.18-2.42) or with >30 quick returns (<28 hours) from night shifts (HR 1.52, 95% CI 1.10-2.10) compared to those who did not work nights. We also observed an excess risk among employees with a long duration (>5 years) of exposure to night shift work (HR 1.87, 95% CI 1.27-2.77), all supported by a dose-response pattern. Our results show that the risk of CeVD among nurses and nursing assistants is associated with night shift work. The number of years with night shift work, the frequency of night shifts per year, the frequency of consecutive night shifts, and short recovery after night shifts influenced the risk. Work schedules aiming at minimizing these aspects of night shift work may reduce the risk.