Background:
While long working hours seem to lead to impaired health, several studies have also shown that long
working hours are related to lower levels of sickness absence. Previous studies on the relationship between long
working hours and sickness absence have compared those who work long hours to those who do not, looking
only at between-individual correlations. Those results might therefore reflect relatively stable differences between
employees who typically work long hours and employees who typically do not. The aim of the present study is to
examine within-individual correlations between long working hours and sickness absence.
Methods:
Records from the Human Resources department in a large Norwegian hospital from 2012 to 2015
provided objective data on both working hours and sickness absence. Two analyses were performed: a prospective
cohort analysis to replicate the results from previous between-individual analyses and a second analysis of within-
individual correlations using a fixed effect design.
Results:
In line with existing research, both between-individual and within-individual analyses showed a negative
relationship between long working hours (> 48 h/week) and short-term sickness absence (1
–
8 days) and no
significant difference in incidence of long-term sickness absence (> 8 days).
Conclusions:
The results indicate that the negative relationship between long working hours and sickness absence
is not due only to relatively stable individual differences between those who typically work long hours and those
who do not. The results from both analyses therefore still contrast with previous research showing a negative
relationship between long working hours and other health indicators.