Background: Nurses often endure working irregular day, night and evening shifts as well as mandatory overtime (i.e. employer-imposed work time in excess of one's assigned schedule). While these work characteristics are examined as potential risks for nurses' safety and health, it is not clear whether negative health impacts occur simply because of working long hours or in combination with other mechanisms.
Aim: This study investigates how these work characteristics are associated with nurses' work-related injury and illness over and above long work hours.
Methods: In this cross-sectional study, questionnaire data were collected from a sample of 655 registered nurses in the Philippines. Multiple logistic regression was used to assess associations of shift work and mandatory overtime with four work-related health outcomes.
Results: After weekly work hours, shift length and demographic variables were accounted for, non-day shifts were associated with work-related injury [odds ratio (OR) = 1.54; 95% confidence interval (CI): 1.07, 2.24] and work-related illness (OR = 1.48; 95% CI: 1.02, 2.16). Also, frequency of working mandatory overtime was associated with work-related injury (OR = 1.22; 95% CI: 1.06, 1.41), work-related illness (OR = 1.19; 95% CI: 1.04, 1.37) and missing more than 2 days of work because of a work-related injury or illness (OR = 1.25; 95% CI: 1.08, 1.44).
Conclusions: These findings suggest that non-day shifts and mandatory overtime may negatively impact nurses' health independent of working long hours. Mechanisms through which these work characteristics affect health, such as circadian rhythm disturbance, nurse-to-patient ratios and work-family conflict, should be examined in future studies.