[Incidence of permanent disability in a cohort of social security-affiliated workers (2004-2007)]

To describe the incidence of permanent disability, both work-related and non-work-related, by several socioeconomic and geographical variables.

We performed a retrospective study of a cohort of 768,454 workers covered by the General Social Security Regimen, followed-up from 2004 to 2007. This study was based on the Continuous Working Life Survey. In the 4 years of follow-up, 7,749 cases in 1,937,921 workers-years were identified. Incidence rates and crude and adjusted rate ratios were estimated by Poisson regression models.

The incidence of non-work-related permanent disability was 10 times greater than that of work-related disability (36.3 versus 3.7 per 10,000 workers-years). The incidences for both non-work-related and work-related disability were higher in men and increased with age and lower education level. For non-work-related permanent disability, the region with the highest incidence was Asturias and that with the lowest was Madrid (56.7 vs. 23.3). For work-related permanent disability, the highest incidence was found in Asturias and the lowest in Navarre (7.8 vs. 1.4). This differential was maintained for work-related and non-work-related permanent disability for Asturias, after adjustment was made by sex, age, educational level, company size and economic activity.

In this study, we observed substantial differences in the incidences of permanent disability by demographic, social and geographical characteristics, which should be analyzed in greater depth, especially the differences observed by regions.