A prospective twin cohort study of disability pensions due to musculoskeletal diagnoses in relation to stability and change in pain.

Pain is known to play an important role in the pathway to becoming work disabled, in particular for award of disability pensions (DP) due to musculoskeletal diagnoses (MSD). This prospective cohort study investigated MSD-related pain stability and/or changes as predictors for DP during a 23-year follow-up. Additionally confounding factors were examined to elucidate whether familial effects (including genetics and family background) or socioeconomic status, other pain, or use of medication would affect the associations between pain and DP. Data were available on 11,224 twins (4399 complete pairs) born before 1958 surveyed through questionnaires about background factors and musculoskeletal (low back, neck, and shoulder) pain impairing work ability in 1975 and 1981. The follow-up data were collected from pension registers until 2004. Cox proportional hazards regression models were used. During the 23-year follow-up, 508 DPs due to MSD, 166 DPs due to osteoarthritis (OA), and 162 DPs due to low back diagnoses (LBD) were granted. Musculoskeletal pain impairing work ability both measured at 1 time point and 6 years apart, and either 1 pain location or multiple locations, predicted increased risk for DP due to MSD, OA, and LBD. The associations were independent of familial confounding factors and of several influential background factors, including headache; migraine; use of analgesics, hypnotics, or tranquillizers; life satisfaction; and education and marital status. This study concluded that musculoskeletal pain impairing work ability is an early and direct predictor for DP due to MSD, OA, and LBD.