Exposure–response relationships between cumulative occupational shoulder exposures and different diagnoses related to surgery for subacromial impingement syndrome

PURPOSE: The aim was to examine associations between cumulative occupational shoulder exposures and different diagnoses related to surgery for subacromial impingement syndrome (SIS).METHODS: We re-analysed data from a previous register-based cohort study of the Danish working population (2,374,403 persons) with follow-up 2003-2008. The outcomes were eight different SIS-related diagnosis codes (M19, M75.1-5, and M75.8-9) in combination with SIS-related surgery codes. Occupational shoulder exposures were estimated by combining occupational codes with an expert-rated job exposure matrix. Cumulative exposure estimates were calculated for 10-year time windows and expressed as exposure-years. We used a logistic regression technique equivalent to discrete survival analysis.RESULTS: Exposure-response relationships were found between most occupational shoulder exposures and the different SIS-related diagnosis codes. For arm-elevation-years, M19, M75.1, and M75.4 reached maximum adjusted odds ratio (ORadj) of 2.0-2.4, while the maximum ORadj for M75.3 was 1.6; we found intermediate values for the remaining diagnoses. The relationships were almost similar for repetition-years and shoulder-load-years. For force-years, maximum ORadj of 1.7-1.9 was seen for M19, M75.1, and M75.4, while M75.3 reached a maximum ORadj of 1.3. For HAV-years, M19, M75.1, and M75.4 reached maximum ORadj of 1.5-1.7, while M75.3 reached a maximum ORadj of 1.1.CONCLUSION: We found associations between all occupational shoulder exposures and the eight different SIS-related diagnoses; exposure-response relationships were found for most diagnoses. The highest risks were seen for M19 (acromioclavicular osteoarthritis), M75.1 (rotator cuff syndrome), and M75.4 (impingement syndrome), and the lowest for M75.3 (calcific tendinitis).