Common mental and musculoskeletal disorders as predictors of disability retirement among Finns

Background: The contribution of common mental disorders (CMD) co-occurring with chronic musculoskeletal disorders (MSD) to disability retirement is not known.

Methods: A nationally representative sample (the Health 2000 survey) comprised 3943 occupationally active Finns aged 30-63. MSD and other chronic disorders were assessed by a physician in a standardized clinical examination, and CMD using the Composite International Diagnostic Interview. Disability pension data for 2000-2011 was retrieved from national pension records. Cox regression was used with censoring for death and pension other than that for disability. Covariate information was based on an interview.

Results: The baseline prevalence of CMD was 9.4% and of MSD 31.1%. CMD co-occurred with MSD in 3.3% of participants. The risks inflicted by CMD and MSD were additive. Thirty-eight per cent of the co-morbid subjects, 18% of those with CMD and 19% of those with MSD retired prematurely during the average follow-up of 8.6 years. Compared with those with neither type of disorder, the hazard ratio (HR) for disability pension was 2.4 (95% CI 1.7-2.7) for CMD only, 2.2 (1.8-2.7) for MSD only, and 4.1 (2.9-5.7) for the occurrence of both, allowing for age, gender, other chronic disorders, working conditions, and socio-economic and lifestyle factors. No synergistic or antagonistic interactive effects were observed.

Limitations: The determinants were measured only once and we had no information on incident disorders during the follow-up.

Conclusions: It is important to identify subjects with both mental and musculoskeletal complaints in order to efficiently support their work ability.