Job strain and the risk of disability pension due to musculoskeletal disorders, depression or coronary heart disease: a prospective cohort study of 69 842 employees

Objectives Observational studies suggest that high job strain is a risk factor for retirement on health grounds, but few studies have analysed specific diagnoses. We examined job strain's association with all-cause and cause-specific disability pensions. Methods Survey responses to questions about job strain from 48 598 (response rate, 68%) public sector employees in Finland from 2000 to 2002 were used to determine work unit- and occupation-based scores. These job strain scores were assigned to all the 69 842 employees in the same work units or occupations. All participants were linked to the disability pension register of the Finnish Centre of Pensions with no loss to follow-up. Cox proportional hazard models were used to calculate HRs and their 95% CIs for disability pensions adjusted by demographic, work unit characteristics and baseline health in analyses stratified by sex and socioeconomic position. Results During a mean follow-up of 4.6 years, 2572 participants (4%) were granted a disability pension. A one-unit increase in job strain was associated with a 1.3- to 2.4-fold risk of requiring a disability pension due to musculoskeletal diseases in men, women and manual workers, depending on the measure of job strain (work unit or occupation based). The risk of disability pension due to cardiovascular diseases was increased in men with high job strain but not in women nor in any socioeconomic group. No consistent pattern was found for disability pension due to depression. Conclusion High job strain is a risk factor for disability pension due to musculoskeletal diseases.