Psychosocial factors at work as predictors of hospitalization for back disorders: a 28-year follow-up of industrial employees.

STUDY
DESIGN: A prospective cohort study.
OBJECTIVES: To study the association of psychosocial factors at work with severe back disorders leading to hospitalization. SUMMARY OF BACKGROUND DATA: Some psychosocial factors at work have been related to back pain, but little is known about their predictive role in severe back disorders.
METHODS: Psychosocial factors at work were studied by questionnaire and interview in 1973 among a cohort of 902 metal industry employees. Information on hospital admissions for back disorders from the Finnish Hospital Discharge Register in 1973-2000 was linked to the data. Cox proportional hazards regression was used to estimate the time between the assessment of risk factors and the first hospital admission for intervertebral disc disorders (36 cases) and other back disorders (47 cases).
RESULTS: In a model including psychosocial factors and potential confounders, low job control versus high control was associated with a 3.2-fold risk (95% confidence interval, 1.3-7.8) of hospitalization for back disorders other than those of the intervertebral disc. The corresponding rate ratio for low versus high supervisor support was 2.9 (95% confidence interval, 1.3-6.3). Job demands, coworker support, and distress were not independently associated with these disorders. The result did not change when patients with chronic back disorder at baseline were excluded from the analysis. There was no association between psychosocial factors at work and hospitalizations for intervertebral disc disorders.
CONCLUSION: Low job control and low supervisor support seem to increase the risk of hospitalization for back disorders other than intervertebral disc disorders.