Occupation, physical workload factors, and disability retirement as a result of hip osteoarthritis in Finland, 2005-2013

Abstract

Objective. To identify occupations with a high risk of disability retirement as a result of hip osteoarthritis (OA), and to examine the effect of physical workload factors on the occupational differences in disability retirement. Methods. A total of 1,135,654 (49.4% women) Finns aged 30-60 years in gainful employment were followed from 2005 to 2013 for full disability retirement as a result of hip OA. Information on pensions, occupation, and education were obtained from national registers. Physical workload was assessed by a sex-specific job exposure matrix. We calculated age-adjusted incidence rates and examined the associations of occupation, education, and physical workload factors with disability retirement using a competing risk regression model. Results. Age-adjusted incidence rate was 25 and 22 per 100,000 person-years in men and women, respectively. Both men and women working in lower-level nonmanual and manual occupations had an elevated age-adjusted risk of disability retirement as a result of hip OA. A very high risk of disability retirement was found among male construction workers, electricians, and plumbers (HR 12.7, 95% CI 8.4-19.7), and female professional drivers (HR 15.2, 95% CI 7.5-30.8) as compared with professionals. After adjustment for age and education, the observed occupational differences in disability retirement were largely explained by physical workload factors among men and to a smaller extent, among women. Conclusion. Our results suggest that education and physical workload factors appear to be the major reasons for excess disability retirement as a result of hip OA in manual occupations, particularly among men.