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Aim: The aim was to examine exposure-response relations between surgery for subacromial impingement syndrome (SIS) and intensities of lifting/carrying and pushing/pulling loads during a 10-year time window.Methods: We conducted a register-based cohort study (2003-2008), comprising persons born in Denmark (1933-1977) with ≥5 years of work experience (N=2 374 403). Information on surgery for SIS was retrieved from the Danish National Patient Register (N=14 188). Occupational mechanical exposures comprising lifting/carrying loads ≥10 kg and pushing/pulling loads ≥50 kg were assessed by combining individual register-based job codes with our expert-based Shoulder job exposure matrix. We created three intensity-specific exposure duration variables by dividing the intensity for lifting/carrying and pushing/pulling loads into three categories (low, medium and high), and summed up number of years in each exposure category for a 10-year time window. The associations were analysed using logistic regression technique equivalent to discrete survival analysis.Results: The adjusted OR (ORadj) increased with both exposure duration and intensity of lifting/carrying and pushing/pulling. For lifting/carrying, the ORadj reached a maximum of 1.78 (95% CI 1.66 to 1.89), 2.52 (95% CI 2.32 to 2.74) and 2.96 (95% CI 2.53 to 3.47) after 10 years of exposures for the three exposure intensities. For pushing/pulling, maximum ORadj was 1.44 (95% CI 1.31 to 1.58), 1.68 (95% CI 1.58 to 1.79) and 1.72 (95% CI 1.50 to 2.00), respectively.Conclusion: We found exposure-response relations for lifting/carrying and pushing/pulling across the 10-year time window. The risk was especially pronounced for lifting/carrying compared with pushing/pulling. We did not find indications of safe exposure intensities. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate if exposure to hand-arm vibration (HAV) is an independent risk factor.Methods: We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003-2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register-based occupational codes (1993-2007) to a general population job exposure matrix to obtain year-by-year exposure intensities on measurement scales for force, upper arm elevation >90° and repetition and expert rated intensities of exposure to HAV. For 10-year exposure time windows, we calculated the duration of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures.Results: We found indications of safe exposure intensities for repetition (median angular velocity <45°/s), while force exertion ≥10% of maximal voluntary electrical activity and upper arm elevation >90° >2 min/day implied an increased risk reaching ORs of 1.7 and 1.5 after 10 years at low intensities. No associations were found for HAV.Conclusions: We found indications of safe exposure intensities for repetition. Any intensities of force and upper arm elevation >90° above minimal implied an increased risk across 10-year exposure time windows. No independent associations were found for HAV. [ABSTRACT FROM AUTHOR]

Objectives: The long-term prognosis for neck-shoulder pain and disorders and the impact of shoulder exposure among former sewing machine operators were investigated in a 14-year follow-up study.Methods: Information on neck-shoulder pain and disorders was collected by questionnaire and clinical examination at baseline in 243 female sewing machine operators and by questionnaire 14 years later. During follow-up, information on comorbidity and job exposures was obtained from registers and by linking register-based D-ISCO 88 codes with a job exposure matrix. Logistic regression analyses were performed to examine associations between neck-shoulder pain and disorders at baseline and neck-shoulder pain and physical functioning at follow-up.Results: We found an association between neck-shoulder disorders at baseline and neck-shoulder pain at follow-up (OR 5.9;95% CI 1.9 to 17.7), and between neck-shoulder pain at baseline and neck-shoulder pain at follow-up (OR 8.2;95% CI 3.5 to 19.2). Associations between neck-shoulder disorders and pain at baseline and limited physical functioning at follow-up had ORs of 5.0 (95% CI 1.5 to 16.1) and 2.2 (95% CI 1.1 to 4.6), respectively. In women still working in 2008, the association between neck-shoulder pain in 1994 and in 2008 seemed to be stronger for those in jobs with high job shoulder exposure.Conclusions: The results suggest a long-term adverse prognosis for neck-shoulder pain. High job shoulder exposure can worsen this prognosis for those who continue working. This knowledge could influence the counselling given to similar workers and emphasises the need to prevent neck-shoulder pain. [ABSTRACT FROM AUTHOR]

Objectives: To estimate the risk of surgery for subacromial impingement syndrome (SIS) in relation to occupational exposures, lifestyle factors and diabetes mellitus.Methods: We conducted a case-control study nested in a register-based cohort study of the Danish working population. For each of 3000 first-time cases of surgery for SIS, two age-matched and sex-matched controls were drawn. Cases and controls received a questionnaire on job history and other factors. Job histories were combined with a psychosocial job exposure matrix (JEM) and the updated Shoulder JEM, which provided exposure intensities on measurement scales. Ten-year cumulative exposures to upper arm elevation >90°, repetitive shoulder movements, forceful shoulder exertions and hand-arm vibrations (HAVs) were estimated. We used conditional logistic regression.Results: There were 5396 persons (60%) who answered the questionnaire. For occupational mechanical exposures, the adjusted OR (ORadj) ranged from 1.9 (95% CI 1.5 to 2.5 for HAVs) to 2.5 (95% CI 1.9 to 3.5 for force) among men and 1.7 (95% CI 1.2 to 2.5 for HAVs) to 2.0 (95% CI 1.3 to 2.9 for force) among women. No statistically significant associations were found for occupational psychosocial factors. Body mass index (BMI) and pack-years of smoking showed ORadj up to 2.0. Diabetes mellitus showed ORadj of 1.5 (95% CI 1.1 to 2.2) for men and 2.2 (95% CI 1.4 to 3.4) for women.Conclusions: Our findings add to the evidence of an increased risk of surgery for SIS in relation to occupational cumulative mechanical exposures, even when an increased risk in relation to BMI, smoking and diabetes mellitus is taken into account. [ABSTRACT FROM AUTHOR]

Objectives: We recently constructed a general population job exposure matrix (JEM), The Shoulder JEM, based on expert ratings. The overall aim of this study was to convert expert-rated job exposures for upper arm elevation and repetitive shoulder movements to measurement scales.Methods: The Shoulder JEM covers all Danish occupational titles, divided into 172 job groups. For 36 of these job groups, we obtained technical measurements (inclinometry) of upper arm elevation and repetitive shoulder movements. To validate the expert-rated job exposures against the measured job exposures, we used Spearman rank correlations and the explained variance[Formula: see text] according to linear regression analyses (36 job groups). We used the linear regression equations to convert the expert-rated job exposures for all 172 job groups into predicted measured job exposures. Bland-Altman analyses were used to assess the agreement between the predicted and measured job exposures.Results: The Spearman rank correlations were 0.63 for upper arm elevation and 0.64 for repetitive shoulder movements. The expert-rated job exposures explained 64% and 41% of the variance of the measured job exposures, respectively. The corresponding calibration equations were y=0.5%time+0.16×expert rating and y=27°/s+0.47×expert rating. The mean differences between predicted and measured job exposures were zero due to calibration; the 95% limits of agreement were ±2.9% time for upper arm elevation >90° and ±33°/s for repetitive shoulder movements.Conclusions: The updated Shoulder JEM can be used to present exposure-response relationships on measurement scales. [ABSTRACT FROM AUTHOR]

Objectives The primary aim was to examine exposure--response relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sex-specific exposure--response relationships. The secondary aim was to examine the time window of relevant exposures. Methods We conducted a nationwide register study of all persons born in Denmark (1933-1977), who had at least 5 years of full-time employment. In the follow-up period (2003-2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis. Results The adjusted OR (ORadj) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure--response relationships were similar for men and women, when assessed using a relative risk scale. The ORadj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%. Conclusions Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure--response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures. [ABSTRACT FROM AUTHOR]