Occupational Biomechanical Exposure Research Articles

Surgery for subacromial impingement syndrome and occupational biomechanical risk factors in a 16-year prospective study among male construction workers.

The aim of this study was to assess the association between occupational biomechanical exposures and the occurrence of surgical treatment for subacromial impingement syndrome (SIS). A cohort of 220 295 male constructions workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively over a 16-year follow-up period (2001-2016) for surgically treated SIS. Worker job title, smoking status, height, weight, and age were registered on health examination. Job titles were mapped to 21 occupational groups based on tasks and training. A job exposure matrix (JEM) was developed with exposure estimates for each occupational group. Surgical cases were determined through linkage with the Swedish national in- and outpatient registers. Poisson regression was used to assess the relative risks (RR) for each biomechanical exposure. The total incidence rate of surgically treated SIS over the 16-year observation period was 201.1 cases per 100 000 person-years. Increased risk was evident for workers exposed to upper-extremity loading (push/pull/lift) (RR 1.45-2.30), high hand grip force (RR 1.47-2.23), using handheld tools (RR 1.52-2.09), frequent work with hands above shoulders (RR 1.62-2.11), static work (RR 1.77-2.26), and hand-arm vibration (RR 1.78-2.13). There was an increased risk for SIS surgery for all occupational groups (construction trades) compared with white-collar workers (RR 1.56-2.61). Occupational upper-extremity load and posture exposures were associated with increased risk for surgical treatment of SIS, which underlines the need for reducing workplace exposures and early symptom detection in highly exposed occupational groups.

Agreement between an expert-rated mini job exposure matrix of occupational biomechanical exposures to the lower body and technical measurements or observation: a method comparison study

ObjectivesInvestigating the agreement between an expert-rated mini job exposure matrix (JEM) of lower body exposures and technical measurements of worktime spent standing/walking and observation-based estimates of time spent kneeling/squatting and...

The non-explicit observational method is reproducible and valid in the analysis of occupational biomechanical exposure of workers

An analysis of workers' exposure to biomechanical risk factors in the workplace with a high methodological quality allows for stronger evidence of the relationship between risk factors and musculoskeletal disorders. To evaluate the measurement properties of non-explicit observational methods. Psychometric study design that included 50 workers in an analysis of occupational tasks (n = 50 video tasks) using a non-explicit observational method, the Rapid Entire Body Assessment (REBA) method, and a workers' self-report on their perception of their biomechanical occupational exposure. The reliability was tested by a non-explicit method and the REBA method. The validity of the non-explicit method was tested using the REBA method and the workers' self-report, according to COSMIN guidelines. The intra- and inter-evaluator reliability of the non-explicit observational method ranged from moderate to strong (ICC2.1 = 0.45 to 0.87), and the agreement was acceptable (SEM = 0.60 to 2.79), expect for neck region. The REBA method showed intra-evaluator reliability to be moderate to excellent (ICC2.1 = 0.50 to 1.00), inter-evaluator reliability to be poor to strong (ICC2.1 = -0.17 to 0.83), and intra- and inter-evaluator agreement to be poor to moderate (SEM = 0.00 to 0.74). The concurrent validity between the non-explicit and REBA methods showed a strong positive correlation. The non-explicit observational method of biomechanical exposure analysis presented reproducible and valid measurement properties. Methods that present better measurement properties provide professionals with a better basis for analysis and assist in decision-making to reduce or eliminate risk exposure.

An ergonomics educational training program to prevent work-related musculoskeletal disorders to novice and experienced workers in the poultry processing industry: A quasi-experimental study

This quasi-experimental study was conducted in a poultry processing industry with the aim of assessing the benefits of ergonomics educational training for novice and experienced workers in preventing work-related musculoskeletal disorders. Sociodemographic and occupational questionnaires were used to evaluate age, marital status, education, time in job, musculoskeletal complaints and pain intensity, perceived effort, biomechanical exposure, and perception of ease or difficulty in adoption of ergonomics educational training. Musculoskeletal complaints in the neck, back, and wrists were reduced with training, but pain intensity was reduced only in the wrist region. A reduction in the occupational biomechanical exposure from the baseline to immediately post-training and 2 months after training both for novice and experienced workers was also observed. The novice workers group differed from the experienced workers by presenting a higher reduction of biomechanical exposure in the cutting room. All workers in this study benefited from the ergonomics educational training in the short and medium term. However, the success of training was highly dependent on the content and approach of the training.

Occupational biomechanical risk factors for radial nerve entrapment in a 13-year prospective study among male construction workers

ObjectivesThe aim was to assess the association between occupational biomechanical exposure and the occurrence of radial nerve entrapment (RNE) in construction workers over a 13-year follow-up period.MethodsA cohort of 229...

Occupational biomechanical risk factors for surgically treated ulnar nerve entrapment in a prospective study of male construction workers.

Objectives The aim of this study was to determine the association between occupational biomechanical exposures and occurrence of surgically treated ulnar nerve entrapment (UNE). Methods A cohort of 229 689 male construction workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively over a 13-year case ascertainment period (2001-2013) for surgically treated UNE. Job title (construction trade), smoking status, height, weight and age were recorded on examination. Job titles were merged into occupational groups of workers performing similar work tasks and having similar training. Occupational biomechanical exposure estimates were assigned to each occupational group with a job exposure matrix (JEM) developed for the study. Negative binomial models were used to assess the relative risks for each biomechanical exposure and the sums of highly correlated biomechanical exposures. Surgical treatment of UNE was determined via a linkage with the Swedish Hospital Outpatient Surgery Register. Results There were 555 cases of surgically treated UNE within the cohort. Workers exposed to forceful hand-grip factors had a 1.4-fold higher relative risk (95% CI 1.18-1.63) of undergoing surgical treatment for UNE compared to unexposed workers. Occupational groups comprising workers exposed to forceful hand-grip work showed the highest risks for UNE and included concrete workers, floor layers, ground preparatory workers, rock blasters, and sheet-metal workers. Conclusion Forceful hand-grip work increases the risk for surgically treated ulnar nerve entrapment.

Development of “MADE”, a French Job exposure matrix for evaluation of biomechanical exposure

This paper presents the stages of development of an occupational biomechanical exposure matrix and preliminary reliability and validity indicators. The expertise-based job exposure matrix, called "MADE" (for "difficult physical conditions and job matrix"), was developed from the French and international classification of jobs for 17 biomechanical exposures. Three pairs of investigators independently rate the frequency and intensity of exposure of each job from 0 to 5; discordant scores within pairs (mean difference >20% for each biomechanical exposure considered) were discussed collectively. Reliability was assessed by the difference between the initial ratings, the number of revised jobs, and the correlation between the two classifications (with transcoding). Validity was studied by correlating variables similar to those from existing United States and Danish matrices. The difference between the mean scores of the pairs was considered to be "fair" (less than one point). Of the 51 paired results studied (17 exposures - 3 pairs of investigators), four coefficients were found to be less than 0.6, and 14 were between 0.6 and 0.7. Forty-nine of the 1,169 job categories were reviewed. Correlation coefficients between the initial classification and transcoding were greater than 0.7. Correlation coefficients between the French, United States and Danish MEE variables were fair to good. An expertise-based job exposure matrix with fairly reliable indicators has been developed, opening up the prospects to improve certain some fields of public health, at both national and international levels.

Observed Differences between Males and Females in Surgically Treated Carpal Tunnel Syndrome Among Non-manual Workers: A Sensitivity Analysis of Findings from a Large Population Study.

ObjectivesWe aimed at assessing whether differences among males and females in carpal tunnel syndrome (CTS) epidemiology might be attributable to segregation with respect to occupational biomechanical exposures or differential access to care by sex.MethodsWe analysed surgically treated cases of CTS occurring among non-manual workers in Tuscany between 1997 and 2000. We conducted a Monte Carlo simulation to estimate the difference in occupational biomechanical exposures between males and females necessary to explain the observed incidence rate ratios. We also accounted for the sex-specific probability of receiving surgery after the diagnosis of CTS, as women were reported to be more likely to undergo surgery in a subset of our study population. We quantified the hypothetical biomechanical overload through the hand activity level (HAL) metric proposed by the American Conference of Governmental Industrial Hygienists. To quantify the effect of HAL on CTS risk, we assumed a prior distribution based on findings from two large cohort studies of industrial workers.ResultsAfter adjustment for the probability of receiving surgery, women showed a 4-fold incidence of CTS as compared with men. To explain this association among non-manual workers, women should have an average value of HAL at least 5 points higher.ConclusionsOur analysis does not support the hypothesis that the difference in CTS incidence between males and females is entirely attributable to occupational risk factors or to differential access to surgery. The causal pathway between sex and CTS might include more determinants such as hormonal factors, anthropometric characteristics, and non-occupational exposure to biomechanical overload (e.g. household tasks).

Sex differences in task distribution and task exposures among Danish house painters: an observational study combining questionnaire data with biomechanical measurements.

ObjectivesSex differences in occupational biomechanical exposures may be part of the explanation why musculoskeletal complaints and disorders tend to be more common among women than among men. We aimed to determine possible sex differences in task distribution and task-specific postures and movements of the upper extremities among Danish house painters, and to establish sex-specific task exposure matrices.MethodsTo obtain task distributions, we sent out a questionnaire to all members of the Painters' Union in Denmark (N = 9364), of whom 53% responded. Respondents reported their task distributions in a typical week. To obtain task exposures, postures and movements were measured in 25 male and 25 female house painters for one whole working day per person. We used goniometers on the wrists, and inclinometers on the forehead and the upper arms. Participants filled in a logbook allowing task-specific exposures to be identified. Percentiles and % time with non-neutral postures were used to characterise postures. Velocity, range of motion, repetitiveness, and variation were used as measures of movement. Cochran-Mantel-Haenszel statistics and unpaired double-sided t-tests with post-hoc Bonferroni correction were used to evaluate sex differences.ResultsStatistically significant (p<0.05) sex differences were revealed in task proportions, but the proportions differed by less than 4%. For task exposures, no statistically significant sex differences were found.ConclusionsOnly minor sex differences were found in task distribution and task exposures regarding postures and movements among Danish house painters. Sex-specific task exposure matrices were established.

Occupational biomechanical exposure predicts low back pain in older age among men in the Gazel Cohort.

Occupational biomechanical exposures are considered as risk factors for low back pain in the working population. It has also been suggested that their effects persist after retirement. Our objectives were to assess the role of past biomechanical occupational exposure on low back pain in early old age among male participants of the Gazel Cohort. Low back pain for more than 30 days in the past 12 months (LBP30) was assessed in 1996 and 2006 using a French version of the Nordic questionnaire in a subsample of the Gazel Cohort. Logistic regression models were used to study associations between LBP30 in 2006 and past occupational biomechanical exposure, self-reported in 1996, taking into account personal and psychosocial work factors self-reported in 1996, and the date of retirement provided by the company. A multinomial model served to study persistent and new cases, according to LBP30 in 1996. We studied 1,520 men aged 58-67 in 2006, most of them retired. Low back pain for more than 30 days in the past 12 months reported in 2006 was related to occupational biomechanical exposure encountered many years earlier (OR 1.55, 95% CI 1.05-2.27 for 10-20 years of exposure to bending/twisting, OR 1.71, 95% CI 1.17-2.49 for >20 years). These associations appeared specific to low back pain for more than 30 days in the past 12 months which persisted between 1996 and 2006. These results suggest that occupational biomechanical exposure during active life has persistent effects among men in early old age, even for people who left the workforce. They point out the importance of preventive measures at work for better health later and appear relevant for policy-making decisions concerning age at retirement.

0049 Association between work exposure, alcohol intake, smoking and Dupuytren’s disease in a large cohort study (Gazel)

ObjectivesIn view of the debate about biomechanical and toxic factors in Dupuytren’s disease, we aimed to describe its relationship with certain occupational factors and alcohol intake and smoking.MethodSubjects in the...

0323 Workplace Psychosocial Risk Factors for Carpal Tunnel Syndrome: A Pooled Prospective Study0323 Workplace Psychosocial Risk Factors for Carpal Tunnel Syndrome: A Pooled Prospective Study

ObjectivesSeven research groups conducted coordinated studies of carpal tunnel syndrome (CTS). In this analysis of the pooled cohort, we estimate associations of workplace psychosocial factors and CTS incidence with adjustment...

Association among work exposure, alcohol intake, smoking and Dupuytren's disease in a large cohort study (GAZEL)

ObjectivesIn view of the debate of factors in Dupuytren’s disease, we aimed to describe its relationship with certain occupational factors, alcohol intake and smoking.SettingThe French GAZEL cohort (employees of Electricité...

Risk of surgery for subacromial impingement syndrome in relation to neck-shoulder complaints and occupational biomechanical exposures: a longitudinal study

The aim of this longitudinal study was to evaluate the risk of surgery for subacromial impingement syndrome (SIS) in relation to neck-shoulder complaints and occupational biomechanical shoulder exposures. The study was based on the Musculoskeletal Research Database at the Danish Ramazzini Centre. We linked baseline questionnaire information from 1993-2004 on neck-shoulder complaints, job titles, psychosocial work factors, body mass index, and smoking with register information on first-time surgery for SIS from 1996-2008. Biomechanical exposure measures were obtained from a job exposure matrix based on expert judgment. We applied multivariable Cox regression. During 280 125 person-years of follow-up among 37 402 persons, 557 first-time operations for SIS occurred. Crude surgery rates increased from 1.1 to 2.5 per 1000 person-years with increasing shoulder load. Using no neck-shoulder complaints and low shoulder load at baseline as a reference, no neck-shoulder complaints and high shoulder load showed an adjusted hazard ratio (HR(adj)) of 2.55 [95% confidence interval (95% CI) 1.59-4.09], while neck-shoulder complaints in combination with high shoulder load showed an HR(adj) of 4.52 (95% CI 2.87-7.13). Subanalyses based on 18 856 persons showed an HR(adj) of 5.40 (95% CI 2.88-10.11) for complaints located specifically in the shoulder in combination with high shoulder load. Based on these findings, persons with neck-shoulder and especially shoulder complaints in combination with high shoulder load seem an obvious target group for interventions aimed at reducing exposures to prevent surgery for SIS.

Prognosis of ulnar neuropathy and ulnar neuropathy-like symptoms in relation to occupational biomechanical exposures and lifestyle

The aim of this paper was to identify prognostic factors for severity of symptoms and disability among patients with ulnar neuropathy confirmed by nerve conduction studies (NCS) or ulnar neuropathy-like symptoms with normal ulnar nerve NCS. We conducted a cohort study based on a matched case-referent study. In 2008, we mailed a questionnaire to 1179 patients who were examined by NCS for suspected ulnar neuropathy at the age of ≥ 18 - < 65 years, 2001-2007. Potential prognostic factors included occupational biomechanical exposures, lifestyle factors, and NCS result. Outcomes were severity of symptoms and disability according to questionnaire scores. Referents delivered reference values. We used ordinal logistic regression. The percentage of those responding was 61%, comprising 324 patients with ulnar neuropathy and 396 with ulnar neuropathy-like symptoms. At follow-up, both patient groups had more severe symptoms and disability than age and sex matched referents. Abnormal NCS indicated a poorer prognosis regarding symptom severity [odds ratio (OR) 1.44, 95% confidence interval (95% CI) 1.01-2.01], but not disability (OR 0.78, 95% CI 0.57-1.08). High occupational force requirements indicated a poorer prognosis regarding both symptom severity (OR 1.78, 95% CI 1.10-2.88) and disability (OR 1.66, 95% CI 1.06-2.59). Other negative prognostic factors for both outcomes were current smoking, obesity, distal upper-extremity fractures, female sex, and a recent NCS date (suggesting improvement over time). NCS confirmation of ulnar neuropathy identified patients with a poorer prognosis regarding symptoms. A negative impact of high occupational force requirements, current smoking, and obesity on both outcomes suggested that reduction of these factors might improve prognosis of ulnar neuropathy and ulnar neuropathy-like symptoms.

Ulnar neuropathy and ulnar neuropathy-like symptoms in relation to biomechanical exposures assessed by a job exposure matrix: a triple case–referent study

ObjectivesWe aimed to evaluate relations between occupational biomechanical exposures and (1) ulnar neuropathy confirmed by electroneurography (ENG) and (2) ulnar neuropathy-like symptoms with normal ENG.MethodsIn this triple case–referent study, we...

Dupuytren's disease: Personal factors and occupational exposure

The etiology of Dupuytren's disease is unknown, and the role of occupational exposure is still debated. Our objective was to study the association between occupational exposures, personal risk factors and Dupuytren's disease. In this cross-sectional survey, nine occupational physicians performed clinical examinations, focused on Dupuytren's disease, of 2,406 French male civil servants employed at the Equipment Ministry in 1998 and interviewed them about medical history, leisure manual exposure and occupational biomechanical exposure to vibrations and manual work. A cumulative occupational exposure score was defined, with three levels of exposure. Dupuytren's disease was diagnosed in 212 men (8.8%). The occupational exposure score was significantly higher in this group of cases than in the rest of the sample (377 (SD280) vs. 223 (SD250), respectively; P < 0.0001). Occupational exposure was associated with Dupuytren's disease (adjusted Odds Ratio = 2.20 [1.39-3.45] for the intermediate and 3.10 [1.99-4.84] for the high exposure groups), with adjustment for age, leisure physical activities, alcohol consumption (> or =5 servings per day), history of diabetes, epilepsy, hand trauma, and familial history of Dupuytren's disease. Manual work exposure was associated with Dupuytren's disease after adjustment for personal risk factors. Longitudinal studies are needed to confirm these results.