LAUSR

Objective To investigate repetitive movements and the use of hand force as causes of treatment for distal upper extremities musculoskeletal disorders Methods A cohort of 202 747 workers in a pension health scheme from 2005 to 2017 in one of 17 jobs (eg, office work, carpentry, cleaning) was formed. Representative electro-goniometric measurements of wrist angular velocity as a measure for repetition and expert-rated use of hand force were used in a job exposure matrix (JEM). Job titles were retrieved from the Danish registers. Outcome was first treatment in the distal upper extremities. In a Poisson regression model, incidence rate ratios (IRRs) of treatment were adjusted for age, calendar-year, diagnosis of rheumatoid arthritis and arm fractures. In further analyses, wrist velocity or hand force was added. Results In men, wrist velocity had an IRR of 1.48 (95% CI 1.15 to 1.91) when the highest exposure level was compared with the lowest but with no clear exposure-response pattern. The effect became insignificant when adjusted for hand force. Hand force had an IRR of 2.65 (95% CI 2.13 to 3.29) for the highest versus the lowest exposure with an exposure-response pattern, which remained after adjustment for wrist velocity. Among women, no increased risk was found for hand force, while wrist velocity showed a significantly protective association with treatment. Conclusions In men, occupational exposure to hand force more than doubled the risk of seeking treatment. The results for exposure to repetition were less clear. In women, we could not find any indications of an increased risk neither for force nor for repetition.