Time trends in disability pensioning for rheumatoid arthritis, osteoarthritis and soft tissue rheumatism in Norway 1968-97

Aims: Disability pensioning with musculoskeletal diagnoses increased more than general disability pensioning in Norway during 1968-97. Incidences of disability pensioning for three main musculoskeletal diseases - rheumatoid arthritis, osteoarthritis and soft tissue rheumatism - during the period 1968-97 were assessed. Changes in incidence were related to changes in Norwegian society with respect to prevalence of these diseases, the number of individuals having high probability of disability pensioning for these diseases, the labour market and legal amendments that may have changed the probability of being granted a disability pension among these patients. Methods: Data on all new disability pensioners aged 50-66 years registered by the National Insurance Administration during 1968-97 and the total population of Norway excluding disability pensioners were used to calculate annual incidence rates of disability pension for the selected musculoskeletal diagnoses. Results: The incidence of disability pension for soft tissue rheumatism and osteoarthritis increased during the study period, and both increased more than the incidence of disability pension in general. The incidence of disability pension for rheumatoid arthritis decreased when compared with disability pensioning in general. The year an upward or downward trend started is similar for osteoarthritis and soft tissue rheumatism for men and women in the age groups studied. Conclusion: Changes in prevalence of a disease seem to be an important factor in explaining differences in time trends of disability pensioning with different diagnoses. Changes in unemployment, female employment, number of manual workers or the legal system do not appear to be related to the increases in incidence of disability pensioning with musculoskeletal diseases.