A case-crossover study of age group differences in objective working-hour characteristics and short sickness absence

Aim: To investigate age group differences in objective working-hour characteristics and their associations with short (1–3 days) sickness absence. Background: Irregular working hours, that is shift work with non-standard schedule, may influence sickness absence rates in hospital workers. Methods: We collected daily working hours and the first incidence of short sickness absence from the employers’ electronic records from 2008 to 2017. A case-crossover study compared the characteristics of the working hours 28 days preceding the sickness absence (exposure window) and 28 days earlier (control window) across 10-year age groups (conditional logistic regression for odds ratios (OR) with 95% confidence intervals (95% CI)). Results: Younger employees had longer working hours and more night and consecutive shifts. Extended weekly working hours were associated with short sickness absence in all age groups. Age-related differences were few: extended working hours among oldest age group (OR: 1.01, 95% CI: 1.00–1.01) and daily working hours in the youngest and middle-age groups (Ors: 1.14–1.17) were associated with increased sickness absence. Conclusions: Length of working hours, and night and consecutive shifts differed between age, but the associations with short sickness absence were similar across all age groups. Implications for Nursing Management: Among older employees, the length of working hours should be paid special attention.