The joint contribution of cardiovascular disease and socioeconomic status to disability retirement: A register linkage study.

BACKGROUND: Whether low occupational class amplifies the risk of disability retirement among employees with cardiovascular disease (CVD) is unknown. We examined this issue in two prospective cohort studies.

METHODS: In the Finnish Public Sector Study and the Helsinki Health Study (n=50.799 employees), prevalent CVD (coronary heart disease or stroke, n=1269) was ascertained using records from national health registers, self-reported doctor-diagnosed diseases, and Rose Angina Questionnaire. Data linkage to national pension registers allowed the follow up of disability retirement among the participants for a mean of six years. We analysed the associations of occupational class and CVD with disability retirement using Cox regression, tested interactions between occupational class and prevalent CVD in predicting disability retirement by calculating the Synergy Index, and pooled the results from the two studies using fixed-effect meta-analysis.

RESULTS: Compared with the participants from high occupational class and no CVD, the participants from the low occupational class without CVD had a 2.13-fold (95% CI 1.97-2.30), those with high occupational class and CVD a 2.18-fold (1.73-2.74); and those with both low occupational class and CVD a 4.49-fold (3.83-5.26) risk of disability retirement. A Synergy Index of 1.55 (1.16-2.06) suggested a greater than additive effect for low occupational class and CVD in combination.

CONCLUSIONS: Individuals with both low occupational class and CVD are at a particularly high risk of premature exit from the labour market due to work disability. These findings suggest that better preventive strategies are needed to improve prognosis in this risk group.