The association between occupational-related mechanical stress and radiographic damage in psoriatic arthritis

Objective

To assess the association between occupational-related mechanical factors and the severity of radiographic peripheral and axial joint damage in patients with longstanding Psoriatic Arthritis (PsA).

Methods

Patients with longstanding PsA (disease duration≥10 years) were identified from a prospective longitudinal cohort. Using an occupation history questionnaire, patients were asked to report all paid employments since the age of 18. The key predictor variables included various occupational-related mechanical exposures. A job classification database was used to rate the level of exposure to various occupational physical activities. The outcomes were the extent of radiographic damage in the peripheral and axial joints, as measured by the modified Steinbrocker score (mSS), and the modified Stokes Ankylosing Spondylitis Spine Score (mSASSS). The association between the predictors and outcome variables was assessed by negative binomial regression models after adjusting for potential confounding variables.

Results

A total of 307 eligible patients were analyzed. In the multivariable analysis, exposure to prolonged repetitive hand movements (exp^(β) 1.17 (95% 1.07, 1.28)) and occupations that required higher level of finger dexterity (exp^(β) 1.27 (95% 1.09, 1.47)) were associated with a higher mSS. With regards to axial damage, none of the occupational exposures or workers abilities was associated with mSASSS.

Conclusion

High level of occupation-related mechanical stress is associated with increased radiographic peripheral joint damage among patients with longstanding PsA. This finding supports the potential role of micro-trauma in the pathogenesis of PsA.