Occupational Mechanical Exposures Research Articles

Dupuytren’s disease and occupational mechanical exposures: a systematic review and meta-analysis

The risk of developing Dupuytren’s disease among workers exposed to occupational mechanical exposures has been reported in few systematic reviews, mainly related to vibration. Expanding the investigation to all occupational...

Hip osteoarthritis and occupational mechanical exposures: a systematic review and meta-analysis.

The aim was to conduct a systematic review and meta-analysis investigating the association between occupational mechanical exposures and hip osteoarthritis. The study was registered in PROSPERO. A systematic literature search was conducted in six databases to identify relevant articles. Two authors independently excluded articles, extracted data, assessed the risk of bias of each included article, and graded the level of evidence. We conducted a meta-analysis using random-effects model and performed a sensitivity analysis stratifying articles based on the risk of bias assessment, study design, and the outcome measurement. Twenty-four articles were eligible for inclusion. The highest pooled odds ratio (OR) was found for combined mechanical exposures [OR 1.7, 95% confidence interval (CI) 1.4-2.0], non-neutral postures (OR 1.7, 95% CI 1.4-2.1), lifting/carrying loads (OR 1.6, 95% CI 1.3-1.9), and climbing stairs (OR 1.6, 95% CI 1.1-2.2). The range of pooled OR for the remaining mechanical exposures (eg, standing, walking, kneeling, squatting, and sitting) was 0.6-1.6. Grading the quality of evidence, a moderate level of evidence was found for the combined mechanical exposures and for lifting/carrying loads. The remaining exposure categories were graded as having either low or very low levels of evidence. Considerable heterogeneity was observed across the included studies, and high-quality literature using objective exposure measurements is warranted. Despite various limitations affecting the comparability, occupational mechanical exposures seem to influence the likelihood of developing hip osteoarthritis.

Using a shoulder exoskeleton in slaughterhouse work: Expectations, experiences, and feasibility

BackgroundWork in the slaughterhouse industry increase the risk of shoulder disorders due to high occupational mechanical exposures. Assistive devices, such as exoskeletons, have been developed to reduce the mechanical exposures, but few studies have investigated exoskeleton's feasibility, when used in a workplace setting. ObjectivesThe objective was to explore managers' and workers' expectations and experiences related to using a shoulder exoskeleton, and to evaluate its feasibility compared to an existing assistive device (a ‘lifting glove’) at a Danish slaughterhouse. ParticipantsThe participants included 26 production line workers and their managers at a packaging department at a large slaughterhouse facility. MethodsIn a 5-month field study, data on worker's expectations and experiences of using a shoulder exoskeleton, was compared to a lifting glove and to working without any assistive device. Data was collected using semi-structured interviews, questionnaires, and on-site observations. ResultsExpectations were that shoulder exoskeletons would reduce the mechanical exposure and strain in workers. Some managers also expected that workers could handle more weight/produce more and that the need for job rotation could be reduced. Workers reported the exoskeleton to ‘straighten the body’, and reduced strain, but e others experienced no perceived support or found donning and doffing too time consuming. ConclusionWe found different expectations as to what the shoulder exoskeleton should achieve. This could influence the evaluation of the feasibility of using a shoulder exoskeleton in slaughterhouse work. To facilitate the feasibility of exoskeletons it is important to explicate different expectations and to allow for individual tailoring in its implementation.

Occupational mechanical exposures as risk factor for chronic low-back pain: a systematic review and meta-analysis.

The association between occupational mechanical exposures and low-back pain (LBP) has been studied in several systematic reviews. However, no systematic review addressing chronic LBP exists. The aim of this systematic review and meta-analysis was to examine the association between occupational mechanical exposures and chronic LBP. The study was registered in PROSPERO. We used an existing systematic review to identify articles published before January 2014. For studies published between January 2014 and September 2022, a systematic literature search was conducted in six databases. Two authors independently excluded articles, extracted data, and assessed risk of bias and level of evidence (GRADE). Meta-analyses were conducted using random-effects models comparing highest versus lowest exposure group with sensitivity analyses based on study quality (low/moderate versus high risk of bias), study design (cohort versus case-control), and outcome definition (non-specific LBP versus specific chronic LBP). Twenty-six articles were included. Highest pooled odd ratios (OR) were found for combined mechanical exposures [OR 2.2, 95% confidence interval (CI) 1.4-3.6], lifting/carrying loads (OR 1.7, 95% CI 1.4-2.2), and non-neutral postures (OR 1.5, 95% CI 1.2-1.9). For the remaining mechanical exposures (ie, whole-body vibrations, standing/walking, and sitting), OR ranged between 1.0 and 1.4. In the sensitivity analyses, generally, higher pooled OR were found in low/moderate risk of bias studies, case-control studies, and studies of specific chronic LBP. Moderate evidence of an association was found for lifting/carrying loads, non-neutral postures, and combined mechanical exposures. Low or very low evidence was found for whole-body vibrations, standing/walking, and sitting. Studies using standardized exposure definition, metric, and technical measurements are highly warranted.

Association between occupational exposures and chronic low back pain: Protocol for a systematic review and meta-analysis.

The association between occupational mechanical exposures and chronic low back pain (LBP) has been widely studied, however, few systematic reviews have evaluated the evidence of an association. Furthermore, little is known of the impact of occupational psychosocial exposures on chronic LBP. The aim of this systematic review and meta-analysis is to study the association between occupational mechanical and psychosocial exposures and chronic LBP. The study will be conducted as a systematic review using another systematic review published in 2014 as basis and has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42021281996. A systematic literature search will be performed in 6 scientific databases to identified potential relevant studies published after 2014. Studies will systematically be excluded through a screening process performed independently by 2 reviewers. Exposures will include occupational mechanical and psychosocial exposures, and outcome will include chronic LBP (LBP ≥3 months, "degenerative" diseases, and lumbosacral radiculopathy). Study population will include persons in or above working age, and study designs will comprise cohort and case-control studies. The quality of each included study will be methodologically assessed by 2 independent reviewers and level of evidence of an association will be graded using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system. In meta-analyses, effect sizes will be addressed using random-effect models, sensitivity analyses will explore the robustness of the meta-analysis, and heterogeneity assessed. This systematic review and meta-analysis will assess the evidence available of the association between occupational mechanical and psychosocial exposures and chronic LBP. The review can provide essential knowledge on the association, exposure-response relationships, thresholds, which may pave the way for political decisions on the occupational environment and the labour market insurance policy.

Associations between single and combined occupational mechanical exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study.

This study aimed to evaluate whether the risk of surgery for subacromial impingement syndrome (SIS) increases with the number of combined occupational mechanical exposures compared with single exposure. We reanalyzed data from a register-based cohort study of the entire Danish working population (N=2 374 403) with 14 118 events of surgery for SIS (2003-2008). Exposure information in 10-year windows was obtained by combining occupational codes with a job exposure matrix. For single and combined mechanical exposures, we created three exposure variables of the number of years with specific exposure intensities with or without co-existing mechanical exposures. We used logistic regression as survival analysis. We found exposure-response relations for duration and intensity of each single mechanical exposure except for repetition. The single effect of arm elevation >90º reached a maximum adjusted odds ratio (ORadj) of 1.7 [95% confidence interval (CI) 1.5-2.0], which increased to 1.8 (95% CI 1.5-2.0), 2.0 (95% CI 1.9-2.2), and 2.2 (95% CI 2.0-2.5) when combined with repetition, force, and both. When combining repetition with arm elevation >90º, force, and both, ORadj increased from 1.5 (95% CI 1.3-1.8) to 2.1 (95% CI 1.8-2.4), 2.5 (95% CI 2.4-2.9), and 2.7 (95% CI 2.4-3.0). For force, ORadj increased from 2.5 (95% CI 2.1-2.9) to 2.6 (95% CI 2.3-2.8), 2.8 (95% CI 2.4-3.2), and 3.0 (95% CI 2.6-3.4). We found an increased risk of surgery for SIS with the number of combined exposures; the risk was especially pronounced when the combined exposures included force.

Occupational lifting, carrying, pushing, pulling loads and risk of surgery for subacromial impingement syndrome: a register-based cohort study

AimThe 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.MethodsWe conducted a register-based cohort...

Predictors of inguinal hernia repair and persistent postoperative pain - impact of occupational mechanical exposures

Predictors of inguinal hernia repair and persistent postoperative pain - impact of occupational mechanical exposures

Disability and return to work after MRI on suspicion of scaphoid fracture: Influence of MRI pathology and occupational mechanical exposures

ObjectivesWe aimed to determine the prognosis after early MRI on clinical suspicion of scaphoid fracture, hypothesising that MRI pathology is associated with more disability and that MRI pathology and high occupational mechanical hand-arm exposures are associated with slower return to work (RTW).MethodsWe conducted a follow-up study of a cohort of 469 patients, who were scanned in the period 2006 to 2010. The respondents constituted our cohort for disability analysis and the subset that was in the labour market at the time of the trauma constituted our sub-cohort for RTW analysis. Questionnaires included disability scores, job title, and lifestyle factors. Job titles were linked with a job exposure matrix to estimate occupational exposures. Register information was obtained on time until RTW. We used logistic regression analysis of disability and Cox regression analysis of time until RTW.ResultsThe proportion that responded was 53% (249/469) for the disability analysis and 59% (125/212) for the RTW analysis. The mean age at follow up was 43.5 years, the mean time since trauma was 4.8 years, 53% had injury of the dominant hand, and 54% had MRI pathology. Men constituted 43% of the cohort and 56% of the sub-cohort. MRI pathology was not associated with more disability [e.g., for a 'Disabilities of the Arm Shoulder and Hand'-score ≥20 the odds ratio was 0.58 (95% confidence interval 0.26–1.17)]. Patients without MRI pathology and with low occupational exposures were off work for an average of four weeks. Patients with MRI pathology or high occupational exposures were off work for twice as long time.ConclusionMRI pathology was not associated with more disability. For patients, who were in the labour market at the time of the trauma, MRI pathology and high occupational mechanical hand-arm exposures were associated with slower RTW.

Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows

ObjectivesWe 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...

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension: prospective cohort study.

Objectives The aim of this study was to determine the prospective association of cumulative mechanical exposure during working life with health-related labor market outcomes. Methods This prospective cohort study combines data from 5076 older workers (age 49-63 years) from the Copenhagen Aging and Midlife Biobank with a job exposure matrix and a national register containing information on social transfer payment. By coding individual job histories from the Danish version of ISCO-codes (International Standard Classification of Occupations), we calculated cumulative occupational mechanical exposures from a JEM for ton-years (lifting 1000 kg each day in one year), lifting-years (lifting loads weighing ≥20 kg >10 times each day in one year), kneeling-years (kneeling for one hour each day in one year) and vibration-years (whole-body vibration for one hour each day in one year). Cox-regression analyses estimated the relative risk of register-based long-term sickness absence (LTSA) and disability pension with cumulative occupational mechanical exposures throughout working life. Analyses were censored for competing events and adjusted for multiple confounders. Results During the follow-up period, 970 persons (19.3%) had ≥1 episode of LTSA and 85 persons (1.7%) were granted a disability pension. Number of ton-, lifting- and kneeling-years showed an exposure-response association with increased risk of LTSA (P<0.0001). In addition, both long term [≥20 years; hazard ratio (HR) 1.76 95% CI 1.39-2.22] and short term (<10 years; HR 1.20 95% CI 1.02-1.41) exposure to kneeling work increased the risk of LTSA. Lifting-years, but not the other mechanical exposures, were associated with risk of disability pension (HR 1.75 95% CI 1.01-3.04). Conclusions Cumulative occupational mechanical exposures during working life - such as lifting and kneeling work - increased the risk of LTSA. Importantly, being exposed to lifting increased the risk of disability pension.

Inguinal hernia repair among men in relation to occupational mechanical exposures and lifestyle factors: a longitudinal study

ObjectivesTo evaluate exposure–response relationships between occupational mechanical exposures and first-time lateral and medial inguinal hernia repair and effects of lifestyle factors. To estimate if occupational mechanical exposures advance the repairs.MethodsThis...

Surgery for subacromial impingement syndrome in relation to occupational exposures, lifestyle factors and diabetes mellitus: a nationwide nested case–control study

ObjectivesTo estimate the risk of surgery for subacromial impingement syndrome (SIS) in relation to occupational exposures, lifestyle factors and diabetes mellitus.MethodsWe conducted a case–control study nested in a register-based cohort...

Reversible median nerve impairment after three weeks of repetitive work.

Objectives The aim of this study was to evaluate the development of impaired median nerve function in relation to hand-intensive seasonal work. We hypothesized that at end-season, median nerve conduction would be impaired and then recover within weeks. Methods Using nerve conduction studies (NCS), we examined median nerve conduction before, during, and after engaging in 22 days of mink skinning. For a subgroup, we used goniometry and surface electromyography to characterize occupational mechanical exposures. Questionnaire information on symptoms, disability, and lifestyle factors was obtained. Results The study comprised 11 male mink skinners with normal median nerve conduction at pre-season (mean age 35.7 years, mean number of seasons with skinning 8.9 years). Mink skinning was characterized by a median angle of wrist flexion/extension of 16º extension, a median velocity of wrist flexion/extension of 22 °/s, and force exertions of 11% of maximal voluntary electrical activity. At end-season, mean distal motor latency (DML) had increased 0.41 ms (P<0.001), mean sensory nerve conduction velocity (SNCV) digit 2 had decreased 6.3 m/s (P=0.004), and mean SNCV digit 3 had decreased 6.2 m/s (P=0.01); 9 mink skinners had decreases in nerve conduction, 5 fulfilled electrodiagnostic criteria and 4 fulfilled electrodiagnostic and clinical criteria (a positive Katz hand diagram) for carpal tunnel syndrome (CTS). Three to six weeks post-season, the changes had reverted to normal. Symptom and disability scores showed corresponding changes. Conclusions In this natural experiment, impaired median nerve conduction developed during 22 days of repetitive industrial work with moderate wrist postures and limited force exertion. Recovery occurred within 3-6 weeks post-season.

Sickness absence and permanent work disability in relation to upper- and lower-body pain and occupational mechanical and psychosocial exposures.

The aim of this study was to examine if combined pain (pain in the upper and lower body), high occupational mechanical exposures, and job strain predict sickness absence and permanent work disability, particularly if co-occurring. This longitudinal study was based on the musculoskeletal research database at the Danish Ramazzini Centre. We linked baseline information from 2001-2004 on musculoskeletal pain, job titles, and covariates with register information on sickness absence and permanent work disability. Mechanical and psychosocial exposure estimates were obtained from job exposure matrices. We used multivariable Cox regression. The study included 25 292 persons. Compared to low occupational mechanical exposures and no pain, low mechanical exposures and combined pain showed an adjusted hazard ratio (HR adj) of 1.81 [95% confidence interval (95% CI) 1.58-2.08], while high mechanical exposures and combined pain showed HR adj3.71 (95% CI 3.24-4.25) for sickness absence. The corresponding values for permanent work disability were 3.35 (95% CI 1.74-6.45) and 4.59 (95% CI 2.36-8.94). Job strain showed an association with sickness absence [HR adj1.24 (95% CI 1.10-1.39)], while low social support was associated with both sickness absence and permanent work disability [HR adj1.30 (95% CI 1.19-1.41) and 2.19 (95% CI 1.41-3.41), respectively]. Combined pain in the upper and lower body was associated with sickness absence and permanent work disability, and high occupational mechanical exposures further increased the risk. Job strain showed a modest association with sickness absence, while low social support at work was associated with both outcomes, especially permanent work disability.

Combined musculoskeletal pain in the upper and lower body: associations with occupational mechanical and psychosocial exposures.

Pain in more than one site is common in working populations. We aimed to characterise combined pain (pain in the upper and lower body) and to evaluate whether the prevalence of combined pain is positively related to combined occupational mechanical exposures to the upper and lower body and to high psychosocial job strain. This cross-sectional study was based on questionnaire data from the Musculoskeletal Research Database at the Danish Ramazzini Centre. The study included 14,081 men and 20,173 women. Occupational exposures were assessed by job exposure matrices. We analysed the prevalence of pain limited to the upper body, pain limited to the lower body, and combined pain in relation to occupational exposures using Poisson regression. During the last year, 23.2 % of the men and 33.9 % of the women reported combined pain, which was characterised by somatisation, illness worrying, and low SF-36 scores. For men, the adjusted prevalence ratio for combined pain was 1.51 [95 % confidence interval (95 % CI) 1.40-1.64] in relation to exposures limited to the upper body and 2.24 (95 % CI 2.11-2.39) in relation to combined exposures. For women, the corresponding adjusted prevalence ratios were 1.56 (95 % CI 1.50-1.63) and 1.55 (95 % CI 1.50-1.61). High job strain was related to pain among men, only. Combined pain may in part be explained by local effects of occupational mechanical exposures acting at more than one site.

Varicose veins in the lower extremities in relation to occupational mechanical exposures: a longitudinal study

ObjectivesTo evaluate if occupational mechanical exposures are associated with an increased risk of surgery for varicose veins (VV) in the lower extremities.MethodsWe conducted a longitudinal study of persons from the...

Occupational mechanical exposures and reoperation after first-time inguinal hernia repair: a prognosis study in a male cohort

The aim of this study was to evaluate exposure-response relationships between occupational mechanical exposures and risk of reoperation after inguinal hernia repair. Using register information, we identified all men born in Denmark 1938-1988, who had their first inguinal hernia repair 1998-2008, and who were 18-65 years old and active in the labour market at the time of surgery. The Danish Hernia Database provided information on repairs and reoperations. We used registered occupational codes and a job exposure matrix based on experts' ratings to estimate total load lifted per day, frequency of heavy lifting, and number of hours per day spent standing/walking. We also obtained register information on sickness absence. Multivariable Cox regression analysis was used. The cohort comprised 34,822 patients. We did not reveal exposure-response relationships between occupational mechanical exposures and the hazard ratio (HR) of reoperation. The percentage of patients with >2 weeks of sickness absence within 8 weeks after surgery increased with total load lifted per day from 15 to 53%. Longer sickness absence was associated with an increased HR of reoperation, but within strata of sickness absence, we found no increase in the HR of reoperation with increasing exposures. We did not find indications that the HR of reoperation was related to occupational mechanical exposures, even after accounting for a potential protective effect of sickness absence. Hence, the exposure-related prolonged duration of sickness absence could not be explained by exposure-related complications that led to reoperation.

Total Hip Replacement due to Primary Osteoarthritis in Relation to Cumulative Occupational Exposures and Lifestyle Factors: A Nationwide Nested Case–Control Study

To investigate the risk of total hip replacement (THR) due to primary osteoarthritis in relation to cumulative occupational mechanical exposures and lifestyle factors. Using register information, we identified first-time THR cases within the Danish working population in 2005-2006. For each case, 2 age- and sex-matched controls were drawn. Persons within 2,500 randomly selected case-control sets received a questionnaire about job history, weight at age 25 years, present weight and height, smoking, and sports activities at age 25 years. The job history was combined with a job exposure matrix. Cumulative exposure estimates were expressed according to the pack-year concept of smoking (e.g., cumulative lifting was expressed as ton-years). We used conditional logistic regression for statistical analyses. In total, 1,776 case-control sets (71%) were available for analysis. The adjusted odds ratio (OR) for exposure to ≥20 ton-years was 1.35 (95% confidence interval [95% CI] 1.05-1.74) for men and 1.00 (95% CI 0.73-1.41) for women. Standing/walking and whole body vibration showed no associations. The adjusted OR for body mass index (BMI) ≥30 kg/m(2) at age 25 years was 2.44 (95% CI 1.38-4.32) for men and 5.12 (95% CI 2.30-11.39) for women. The corresponding adjusted ORs for an increase in BMI of ≥10 kg/m(2) since age 25 years were 2.16 (95% CI 1.25-3.70) and 2.46 (95% CI 1.47-4.13). Sports participation showed weak positive associations, while pack-years of smoking showed no associations. The results indicated a modest increase in risk of THR in relation to cumulative lifting among men and an increased risk in relation to a high BMI at age 25 years and to a gain in BMI in both sexes.

0190 Carpal tunnel syndrome and carpal tunnel syndrome-like symptoms in relation to mechanical exposures assessed by a job exposure matrix: a triple case-referent study

ObjectivesTo evaluate relations between occupational mechanical exposures and (1) carpal tunnel syndrome verified by ENG (ENG+CTS) and (2) CTS-like symptoms with normal ENG (ENG-CTS).MethodWe plan a triple-case referent study of...