Age-group differences in associations of working hour characteristics and short sickness absences

Abstract

Abstract Background Working-hour characteristics are linked to disturbed sleep, but little is known about their association with short sickness absences (SA). We investigated the association between working hour characteristics in shift work and the incidence of short (1-3 days) SA in three age groups. Methods The data was from the hospitals’ electronic working time records. The final sample was restricted to the first incidence of short SA (1-3 days) from 2008 to 2015 and to shift working employees (n = 12156, 89% women). Age groups were < 35 (n = 5652), 35-49 (n = 3592) and ≤ 50 years (n = 2545). Work shifts (morning, day, evening, and night), quick returns (< 11 hours between two work shifts), length of work shift and weekly working time were calculated for case-crossover study design to compare the working hour characteristics of the 28 days preceding SA (exposure window) and those of the 28 days before the exposure window (control window). Conditional logistic regression models were run for odds ratios (OR) with 95% Confidence Intervals (95%CI). Results Working hour characteristics, especially length of working hours, played the clearest role among those < 35 years of age. In this age group, exposure to > 25% of > 40 weekly working hours associated with an increased likelihood of short SA (OR 1.30, 95%CI 1.17-1.44), whereas weekly working hours had OR 1.02 (95%CI 1.02-1.03). Having only a few (≤ 4) quick returns decreased the likelihood of SA (ORs 0.31-0.54), whereas having ≥25 quick returns increased it (OR 2.75, 95%CI 2.44-3.11). The results showed mostly similar trends among those of 35-49 years of age whereas among older workers (≤ 50 years) only an association for quick returns was observed. Conclusions Long working hours increase the risk of short SA among those ≤ 49 years of age and several quick returns among all age groups. These working-hour characteristics should be avoided to minimize SA and increased costs for the employer, but also to maintain public health. Key messages Unhealthy working-hour characteristics should be paid special attention in shift scheduling to avoid sickness absence. Good shift scheduling could assist in maintaining workability and therefore public health.