Depressive symptoms and the risk of long-term sickness absence: a prospective study among 4747 employees in Denmark

BACKGROUND: The aim of this paper is to examine the impact of depressive symptoms on long-term sickness absence in a representative sample of the Danish workforce.

METHODS: This prospective study is based on 4,747 male and female employees, participating in the Danish Work Environment Cohort Study. Depressive symptoms were measured at baseline. Data on sickness absence were obtained from a national register on social transfer payments. Onset of long-term sickness absence was followed up for 78 weeks.

RESULTS: The cumulative 78 weeks incidence for the onset of long-term sickness absence was 6.5% in men and 8.9% in women. Both men and women with severe depressive symptoms (<or=52 points) were at increased risk of long-term sickness absence during follow-up (men: HR=2.69; 95% CI: 1.18, 6.12; women: HR=2.27; 95% CI: 1.25, 4.11), after adjustment for demographic, health related, and lifestyle factors. When we divided the depressive symptom scores into quartiles, we found no significant effects with regard to long-term sickness absence.

CONCLUSIONS: Severe depressive symptoms, as measured with the MHI-5, increased the risk of future long-term sickness absence in the general Danish working population. However, effects were not linear, but occurred mostly only in those employees with high levels of depressive symptoms.