Background

The study aimed to explore which sociodemographic, health-related, and work-related factors were associated with the number of sickness absence days during 18 months among employees on sickness absence due to common mental disorders.

Methods

A longitudinal study with participants from a cluster-randomized controlled trial was conducted. Participants from both intervention and control groups were treated as one cohort. Factors included in the analysis were sociodemographic, health-related, and work-related variables collected through questionnaires at baseline. The outcome was cumulative net sickness absence days for sickness absence spells exceeding 14 days and was collected from a national register. Data was analyzed using generalized estimating equations.

Results

The sample consisted of 197 employees. Lower-rated work ability in relation to physical demands ([exp (B) 1.19], 95% CI 1.02–1.40) and higher-rated job demands ([exp (B) 1.28], 95% CI 1.01–1.61), were associated with increased number of sickness absence days during the 18 months follow-up. Higher certainty of return to work within three months ([exp (B) 0.63], 95% CI 0.48–0.83) was associated with a decreased number of sickness absence days during the 18 months follow-up.

Conclusions

Our study suggests that work-related factors, i.e., high job demands and impaired work ability, are associated with an increased number of days on sickness absence. Additionally, the certainty of returning to work within three months is associated with fewer days on sickness absence. The results highlight the importance of addressing specific workplace factors when designing interventions aimed at decreasing sickness absence for employees on sickness absence due to CMDs. The results could be used to inform a dialogue between healthcare personnel and employees on sickness absence due to CMDs, and to serve as basis for a structured inventory to assist healthcare personnel in addressing workplace factors.