Work above shoulder level and shoulder complaints: a systematic review

Influence of brick laying height on biomechanical load in masons: Cross-sectional field study with technical measurements

BACKGROUND

Work-related musculoskeletal disorders (WMSDs) located in the low back and neck/shoulder regions are major concerns for both workers, workplaces, and society. Masons are prone to WMSD, because their work is characterized by repetitive work and high physical workload. However, the knowledge on the physical workload during bricklaying is primarily based on subjective measurements.

OBJECTIVE

This cross-sectional field study with technical measurements aimed to quantify physical workload in terms of muscular activity and degree of forward bending during bricklaying at different working heights among masons, i.e., knee, hip, shoulder, and above shoulder height.

METHODS

Twelve male (36.1±16.1 years) experienced masons participated in a cross-sectional field study with technical measurements. Surface electromyography from erector spinae longissimus and upper trapezius muscles and an inertial measurement unit-sensor placed on the upper back were used to assess the physical workload (level of muscle activation and degree of forward bending) different bricklaying heights. Manual video analysis was used to determine duration of work tasks, frequency, type, and working height. The working heights were categorized as 'knee', 'hip', 'shoulder', and 'above shoulder'. The 95 percentiles of the normalized Root Mean Square (RMSn) values were extracted assess from erector spinae and trapezius recordings to assess strenuous level muscle of muscle activation.

RESULTS

The RMSn of dominant erector spinae muscle increased from hip- to shoulder height (from 26.6 to 29.6, P <  0.0001), but not from hip to above shoulder height and decreased from hip to knee height (from 26.6 to 18.9, P <  0.0001). For the dominant trapezius muscle, the RMSn increased from hip- to shoulder- and above shoulder height (from 13.9 to 19.7 and 24.0, respectively, P <  0.0001) but decreased from hip- to knee height (from 13.9 to 11.5, P <  0.0001). Compared to hip height (27.9°), an increased forward bending was detected during bricklaying at knee height (34.5°, P <  0.0001) and a decreased degree of forward bending at shoulder- and above shoulder height (17.6° and 12.5°, P <  0.0001, respectively).

CONCLUSION

Based on technical measurements, bricklaying at hip height showed the best compromise between muscular load and degree of forward bending. This study contributes to the development of the work environment for masons and can help guide preventive initiatives to reduce physical workload.

Influence of an upper limb exoskeleton on muscle activity during various construction and manufacturing tasks

Musculoskeletal disorders (MSDs) significantly impact workers in the manufacturing and construction sectors. One solution that has gained interest to reduce MSDs incidence is the use of exoskeletons. In this study, the influence of an upper limb exoskeleton on muscle activity was investigated experimentally for three commonly performed tasks in the manufacturing and construction sectors. The tasks tested were overhead assembly, bricklaying, and box moving tasks. Eighteen males participated in the tests. The results showed a reduction in shoulder flexor muscle activation during all three tasks (up to -45.46 ± 4.52% for the anterior deltoid), but increased extensor activation (up to 15.47 ± 8.01% for the latissimus dorsi) was observed when the task was not primarily performed above shoulder level. The results revealed the dependence of the upper-body exoskeleton on tasks and arm posture, which should be considered for both in-field applications and designing new exoskeletons for performance enhancement.

Testing the association between shoulder pain prevalence and occupational, physical activity, and mental health factors in two generations of Australian adults

BACKGROUND

Shoulder pain is common among the adult population, but it appears to reduce in prevalence around retirement age. Associations between shoulder pain and work-place exposures, physical activity, or mental health status are unclear and may change with age. This study aimed to determine the prevalence of self-reported shoulder pain in Australian adults across two generations and test the association with occupational factors, physical activity, and mental health.

METHODS

In this cross-sectional study we used data from a longitudinal Australian pregnancy cohort (the Raine Study). We analysed data from the children (Gen2) at the 22-year follow-up (N = 1128) and parents (Gen1) at the 26-year follow-up (N = 1098). Data were collected on self-reported shoulder pain, occupational factors (employment status and work description), physical activity, and mental health at the respective follow-ups. Prevalence rates were provided as percentages with 95% confidence intervals. Univariate analysis for group comparisons included chi squared for categorical comparisons. The association of predictor variables and shoulder pain was assessed using logistical regression.

RESULTS

In Gen1 31.4% of adults aged 40-80 reported the presence of shoulder pain in the last month, with no significant difference between females and males. Gen1 participants younger than 65 reported more shoulder pain (OR[95%CI] = 1.80 [1.04-3.09]). Gen2 females (14.7%) reported shoulder pain in either shoulder more frequently than males (7.7%) and bilateral shoulder pain (8.0%) more frequently than males (1.9%). Gen1 had increased odds of reporting shoulder pain if their work was "physical or heavy manual" compared to "sedentary" (OR [95% CI] = 1.659 [1.185-2.323]) and when categorised with depression (OR [95% CI] = 1.940 [1.386-2.715]) or anxiety (OR [95% CI] = 1.977 [1.368-2.857]). Gen2 participants with depression (OR [95% CI] = 2.356 [1.620-3.427]) or anxiety (OR [95% CI] = 2.003 [1.359-2.952]) reported more shoulder pain.

CONCLUSION

Overall, shoulder pain was more prevalent in young females than males and was more prevalent in those under the age of 65. Cross-sectional associations were established between some occupational factors in older adults and depression in all adults, and shoulder pain.

Arm-support exoskeleton reduces shoulder muscle activity in ceiling construction

The objective of this study was to assess the efficacy and user's impression of an arm-support exoskeleton in complex and realistic ceiling construction tasks. 11 construction workers performed 9 tasks. We determined objective and subjective efficacy of the exoskeleton by measuring shoulder muscle activity and perceived exertion. User's impression was assessed by questionnaires on expected support, perceived support, perceived hindrance and future intention to use the exoskeleton. Wearing the exoskeleton yielded persistent reductions in shoulder muscle activity of up to 58% and decreased perceived exertion. Participants reported limited perceived hindrance by the exoskeleton, as also indicated by no increase in antagonistic muscle activity. The findings demonstrate the high potential of an arm-support exoskeleton for unloading the shoulder muscles when used in the dynamic and versatile working environment of a ceiling construction worker, which is in line with the consistent intention of the workers to use the exoskeleton in the future.Practitioner Summary: The majority of research focuses on the effect of using an arm-support exoskeleton during isolated postures and prescribed movements. We investigated the efficacy of an exoskeleton during a complex and realistic work, namely ceiling construction. Shoulder muscle activity was lower in almost all tasks when wearing the exoskeleton.

Development and validation of a work-related risk score for upper-extremity musculoskeletal disorders in a French working population

OBJECTIVES

The aim was to develop an easy-to-use risk score based on occupational factors and to validate its performance to identify workers either having (diagnostic setting) or developing (prognostic setting) upper-extremity musculoskeletal disorders (UEMSD).

METHODS

This study relied on data from the Cosali prospective cohort conducted in a French working population. Diagnostic status for six UEMSD at inclusion and at follow-up was assessed by a standardized clinical examination. Data on occupational factors were collected through a self-administered questionnaire completed before the clinical examination at inclusion. The risk score was derived from a prediction model developed on data of 2,468 workers included in 2002-2003, and the validation sample is composed of 1,051 workers included later in 2004-2005. The prognostic performance of the risk score was assessed in workers without UEMSD at baseline.

RESULTS

A total of 13% and 12% of workers had a UEMSD at inclusion in the development and validation sample. The developed risk score includes physical, organizational and psychosocial factors at work. In the validation sample, this score had acceptable performance for identifying workers having or not UEMSD at baseline (AUC: 0.60 [95% CI 0.57 to 0.63]), in particular the negative predictive value was high (89%-90%). The baseline risk score showed similar performance for predicting incident UEMSD at follow-up examination.

CONCLUSION

This score can be useful as a first-line risk assessment tool, especially for excluding the low-risk work situations from further intervention by an ergonomist. Further validation studies are needed to determine its performance among various working populations.

Shoulder Tendinopathies and Occupational Biomechanical Overload: A Critical Appraisal of Available Evidence

BACKGROUND

The aim of this study is to evaluate the association between occupational exposure to biomechanical risk factors and shoulder tendinopathies.

METHODS

We updated recent systematic reviews about specific shoulder disorders and work-related risk factors. MEDLINE was searched up to September 2022. Studies satisfying the following criteria were included: i) the diagnosis was based on physical examination plus imaging data (when available), and ii) the exposure assessment was based on video analysis and/or directly measured.

RESULTS

Five studies met the inclusion criteria: three cross-sectional studies identified from published systematic reviews and two cohort studies retrieved from the update. Two studies investigated shoulder tendinitis, one supraspinatus tendinitis, and the other two rotator cuff syndrome. The diagnosis was based on physical examination, not supported by imaging techniques for all the included studies. In four out of five studies, the exposure was assessed by experienced ergonomists with the support of video recordings. In two studies, the exposure assessment was further supplemented by force gauge measurements or direct measurements of upper arm elevation. Only the combined exposure of working with arms above shoulder level with forceful hand exertion appears to be associated with rotator cuff syndrome: i) a cohort study reported an HR=1.11 (95%CI 1.01-1.22) for each unit increase in forceful repetition rate when the upper arm is flexed ≥45° for ≥29% of the working time; and ii) a cross-sectional study showed an OR=2.43 (95%CI 1.04-5.68) for the combination of upper arm flexion ≥45° for more than 15% of the time with a duty cycle of forceful exertions more than 9% of the time.

CONCLUSIONS

There is moderate evidence of a causal association between shoulder tendinopathy and combined exposures of working above shoulder level with forceful hand exertion. The evidence is insufficient for any single biomechanical exposure on its own. High-quality cohort studies with direct exposure measures and objective diagnostic criteria are needed. The occupational origin of shoulder tendinopathies is still an open question that must be properly answered.

Physical Work Demands of Maintenance Workers on Onshore Petroleum Facilities in Norway: An Observational Study Utilizing Wearable Sensor Technology

OBJECTIVES

High physical work demands can cause musculoskeletal disorders and sick leave in petroleum workers. However, our knowledge of their physical work demands is scarce and based on self-report. The objective of our study is to work towards closing this knowledge gap by assessing the physical work demands of onshore petroleum maintenance workers using body-worn sensors.

METHODS

A total of 46 of 69 eligible maintenance workers (37 mechanics and 9 process technicians) from three onshore petroleum facilities in Norway filled in a questionnaire and diary and wore five accelerometers and a heart rate sensor for up to six consecutive workdays. Work-related physical activity and postures were classified using rule-based modelling in a modified version of the validated Acti4 software.

RESULTS

The onshore maintenance petroleum workers were working an average of 10 h a day and spent on average this time with 48% (SD = 16.5) sitting, 1% (SD = 2.8) lying down, 39% (SD = 16.2) in light physical activity, and 9% (SD = 3.8) in moderate to vigorous physical activity. During work hours while at feet, we found arm elevation ≥60° to be 11% (SD = 7.1) (68 min), and forward bending of the trunk ≥60° to be 2% (SD = 2.2) (14 min). The workers spent 2% (SD = 2.5) (12 minu) of the workhours kneeling. We observed a high inter-individual variation for all these work exposures. Moreover, 26% (12) of the workers conducted static standing for >30% of the workday, and 17% (8) spent more than half of the work hours >33% of their estimated maximal cardiovascular capacity.

CONCLUSIONS

While onshore maintenance petroleum workers on average spend about half of the workday sitting or lying down, the remaining worktime is spent with a rather high duration of arm elevation and forward bending. Quite high fraction of the workers spends much of the workhours in static standing and kneeling. We see a substantial variation in these work exposures between the workers. The findings indicate a need for preventive measures in how work is organized and performed.

Can home care work be organized to promote health among the workers while maintaining productivity? An investigation into stakeholders' perspectives on organizational work redesign concepts based on the Goldilocks Work principles

BACKGROUND

Due to the aging population, the need for home care services is increasing in most Western countries, including Norway. However, the highly physical nature of this job could contribute to make recruiting and retaining qualified home care workers (HCWs) challenging. This issue may be overcome by adopting the Goldilocks Work principles, aiming at promoting workers' physical health by determining a "just right" balance between work demands and recovery periods while maintaining productivity. The aim of this study was to 1) gather suggestions from home care employees on suitable organizational (re)design concepts for promoting HCWs' physical health and 2) have researchers and managers define actionable behavioral aims for the HCWs for each proposed (re)design concept and evaluate them in the context of the Goldilocks Work principles.

METHODS

HCWs, safety representatives, and operation coordinators (n = 14) from three Norwegian home care units participated in digital workshops led by a researcher. They suggested, ranked, and discussed redesign concepts aimed at promoting HCWs' health. The redesign concepts were subsequently operationalized and evaluated by three researchers and three home care managers.

RESULTS

Workshop participants suggested five redesign concepts, namely "operation coordinators should distribute work lists with different occupational physical activity demands more evenly between HCWs", "operation coordinators should distribute transportation modes more evenly between HCWs", "Managers should facilitate correct use of ergonomic aids and techniques", "HCWs should use the stairs instead of the elevator", and "HCWs should participate in home-based exercise training with clients". Only the first two redesign concepts were considered to be aligned with the Goldilocks Work principles. A corresponding behavioral aim for a "just right" workload was defined: reduce inter-individual differences in occupational physical activity throughout a work week.

CONCLUSIONS

Operation coordinators could have a key role in health-promoting organizational work redesign based on the Goldilocks Work principles in home care. By reducing the inter-individual differences in occupational physical activity throughout a work week, HCWs' health may be improved, thus reducing absenteeism and increasing the sustainability of home care services. The two suggested redesign concepts should be considered areas for evaluation and adoption in practice by researchers and home care services in similar settings.

Comparison of compensatory shoulder movements, functionality and satisfaction in transradial amputees fitted with two prosthetic myoelectric hooks

The functionalities of myoelectric hooks, such as whether they allow wrist movements, as well as the volume and design of the devices, may impact how fitted transradial amputees use their upper limbs. The aim of the current study was to compare two prosthetic myoelectric hooks in terms of compensatory shoulder movements, functionality and user satisfaction. This monocentric, randomized, controlled, cross-over trial evaluated eight transradial amputees fitted with two prosthetic myoelectric hooks, the Greifer and the Axon-Hook, during two consecutive periods. At the end of each period, shoulder abduction (mean and percentage of time with shoulder abduction > 60°) and manual dexterity were assessed using the Box and Blocks Test (BBT) on both sides, and satisfaction was assessed with the Evaluation of Satisfaction with Assistive Technology questionnaire. For each patient, data obtained with the BBT on the amputated side were compared with those obtained on the non-amputated side. Shoulder abduction was significantly higher with the Greifer (60.9°± 20.3°, p = 0.03) than with the Axon-Hook (39.8°± 16.9°) and also than with the NA side (37.6 ± 19.4°, p = 0.02). Shoulder abduction on the NA side (37.6 ± 19.4°) was close to that of the Axon-Hook (39.8°± 16.9°). The percentage of time spent with shoulder abduction > 60° during the BBT was higher with the Greifer than with the Axon-Hook or with the NA side (53.3 ± 34.4%, 17.6 ± 27.0% and 18.4 ± 34.9%, respectively), but the differences were not significant (p = 0.15). A significant strong negative correlation was found between shoulder abduction and wrist position with the Axon-Hook (r = -0.86; p < 0.01), but not with the Greifer. Manual dexterity and satisfaction did not differ significantly between the two devices. These results revealed compensatory movements, such as shoulder abduction in transradial amputees equipped with hooks, themselves influenced by the prosthetic device settings.

The Correlation of Frequency of Work-Related Disorders with Type of Work among Polish Employees

Musculoskeletal disorders have a significant negative impact on the quality of life of the population. These conditions, as well as other work-related disorders, generate costs associated with treatment and work absence, which makes it a growing problem in industrialized countries. Available data from studies on individual populations of workers indicate a higher incidence of certain symptoms in these groups. Due to the lack of studies on the general population, we aimed to perform the preliminary study evaluating the occurrence of pain and work-related conditions depending on the type of occupational work among Polish employees to identify further possible areas for research. Data was collected using an electronic self-administered questionnaire, which was distributed in groups bringing together various professionals. The data obtained from 379 participants have been analyzed and divided according to performed work into sedentary, forced posture, standing, physical and requiring physical activity. Our study reveals a correlation between the frequency of work-related disorders and type of work performed in the Polish population. A significant correlation between the type of occupational work and prevalence of ankle, knee and shoulder pain, as well as heavy legs or upper limb paresthesia was found. According to our findings, female employees may be more vulnerable to lower limb symptoms. A place of residence also seems to affect the prevalence of upper back pain and heavy legs. The analysis also showed a correlation between the occurrence of hip, knee and ankle pain and the level of education of the participants. Surprisingly, lower extremity paresthesia was significantly more common among participants undertaking additional physical activity, compared to non-physically active respondents.

Occupational demands associated with rotator cuff disease surgery in the UK Biobank

OBJECTIVES

Physically-demanding occupations may increase rotator cuff disease (RCD) risk and need for surgery. We linked a job-exposure matrix (JEM) to the UK Biobank cohort study to measure physical occupational exposures and estimate associations with RCD surgery.

METHODS

Jobs and UK Standard Occupational Classification (SOC) codes were recorded during the UK Biobank verbal interview. Lifetime job histories were captured through a web-based survey. UK SOC codes were linked to a JEM based on the US O*NET database. O*NET-based scores [static strength, dynamic strength, general physical activities, handling/moving objects (range=1-7), time spent using hands, whole body vibration, and cramped/awkward positions (range=1-5)] were assigned to jobs. RCD surgeries were identified through linked national hospital inpatient records. Multivariable Cox regression was used to calculate hazard ratios (HR) as estimates of associations with RCD surgery. Among those with lifetime job histories, associations were estimated for duration of time with greatest exposure (top quartile of exposure).

RESULTS

Of 277 808 people reporting jobs, 1997 (0.7%) had an inpatient RCD surgery. After adjusting for age, sex, race, education, area deprivation, and body mass index, all O*NET variables considered were associated with RCD surgery (HR per point increase range=1.10-1.45, all P<0.005). A total of 100 929 people reported lifetime job histories, in which greater exposures were significantly associated with RCD surgery after >10 years of work (eg, HR for 11-20 versus 0 years with static strength score ≥4 = 2.06, 95% confidence interval 1.39-3.04).

CONCLUSIONS

Workplace physical demands are an important risk factor for RCD surgery, particularly for workers with more than a decade of exposure.

Passive shoulder exoskeleton support partially mitigates fatigue-induced effects in overhead work

BACKGROUND

Despite the potential of occupational passive shoulder exoskeletons (PSEs) to relieve overhead work, limited insights in overhead work precision performance impedes large-scale adoption in industry.

OBJECTIVE

To investigate the effect of PSE support on the reduction in task performance caused by physical fatigue.

METHODS

This experiment consisted of a randomized, counterbalanced cross-over design comparing Exo4Work PSE support and no support, in a physically fatigued state and a control condition. Precision performance was determined using execution speed and drilling errors. Muscle activity and shoulder joint kinematics were recorded.

RESULTS

Fatigue altered task performance, shoulder joint kinematics, muscle activity and subjective experience during overhead work. The PSE support mitigated the fatigue-induced changes in shoulder kinematics. Additionally, a part of the fatigue-induced co-activation of shoulder stabilizing muscles was avoided when working with the PSE. The PSE support also reduced the activity of the anterior and medial deltoid.

CONCLUSION

Physical fatigue provokes compensatory movements and increased co-contraction of muscles when executing overhead work. These fatigue-induced alterations are generally believed to increase the overall musculoskeletal load. The support provided by the PSE reduced muscle activity of muscles working to elevate the arm, but also partially mitigated those fatigue-induced effects.

SIGNIFICANCE

This study shows that the effect of PSE support on precision performance is limited, and suggested that, apart from the known effects of PSE support during overhead work, wearing the exoskeleton in a physically fatigued state may provide additional advantages.

Does occupational forward bending of the back increase long-term sickness absence risk? A 4-year prospective register-based study using device-measured compositional data analysis

OBJECTIVE

Forward bending of the back is common in many jobs and a risk factor for sickness absence. However, this knowledge is based on self-reported forward bending that is generally imprecise. Thus, we aimed to investigate the dose-response relation between device-measured forward bending at work and prospective register-based risk of long-term sickness absence (LTSA).

METHODS

At baseline, 944 workers (93% from blue-collar jobs) wore accelerometers on their upper back and thigh over 1-6 workdays to measure worktime with forward bending (>30˚ and >60˚) and body positions. The first event of LTSA (≥6 consecutive weeks) over a 4-year follow-up were retrieved from a national register. Compositional Cox proportional hazard analyses were used to model the association between worktime with forward bending of the back in an upright body position and LTSA adjusted for age, sex, body mass index (BMI), occupational lifting/carrying, type of work, and, in an additional step, for leisure time physical activity (PA) on workdays.

RESULTS

During a mean worktime of 457 minutes/day, the workers on average spent 40 and 10 minutes on forward bending >30˚ and >60˚ in the upright position, respectively. Five more minutes forward bending >30˚ and >60˚ at work were associated with a 4% [95% confidence interval (CI) 1.01-1.07] and 8% (95% CI 1.01-1.16) higher LTSA risk, respectively. Adjustment for leisure-time PA did not influence the results.

CONCLUSION

We found a dose-response association between device-measured forward bending of the back and prospective LTSA risk. This knowledge can be integrated into available feasible methods to measure forward bending of the back for improved workplace risk assessment and prevention.

Ergonomic and individual risk factors for musculoskeletal pain in the ageing workforce

Background

The present study aimed to investigate the possible association between specific ergonomic and individual risk factors and musculoskeletal pain (MSP) in the back, shoulder, hip and knee region in workers aged 50-65y.

Methods

The study was a population based cross-sectional survey. The study population comprised citizens born between 1952–1966, living in Esbjerg municipality, Denmark, ultimo 2016 (n = 23,463). A questionnaire was sent electronically or by mail. The analysis included the working population only. A multivariate logistic regression was used for each of the following dependent variables; musculoskeletal pain for the past 3 months in the back, shoulder, hip and knee, where independent variables included ergonomic exposure, age, sex, body mass index (BMI) and leisure time physical activity (LTPA).

Results

The overall response rate was 58% and the data of individuals at work (n = 9,263) demonstrated several ergonomic exposures with increased odds for pain in specific regions. Exposure to back twisted or bend, squatting or lying on knees and to carrying or lifting were associated with musculoskeletal pain in the back, whereas exposure to back twisted or bend, arms above shoulder and repeated arm movement were associated with pain in the shoulder. Exposure to back twisted or bend, repeated arm movement, squatting or lying on knees and to carrying or lifting were associated with musculoskeletal pain in the hip. Important individual risk factors were also identified. Increasing age was significantly associated with increased pain in the hip but associated with less risk for pain in the back and shoulder. Males had higher odds for pain in the back and knee compared to females but lower odds for pain in the hip. BMI was particularly important for knee pain. The level of LTPA did not have an important association with MSP in any region.

Conclusion

There is a significant positive association between ergonomic exposures and musculoskeletal pain, which were specific for the back, shoulder, hip and knee. In addition, the data demonstrated a differential association with age, sex and BMI. This needs to be considered for the treatment and classification of musculoskeletal pain and for future preventive initiatives.

Influence of different passive shoulder exoskeletons on shoulder and torso muscle activation during simulated horizontal and vertical aircraft squeeze riveting tasks

Aircraft manufacturing involves riveting utilizing squeeze riveting tools at heights from below elbow to overhead levels. This study assessed utilization of passive shoulder exoskeletons on shoulder and torso muscle activation during simulated squeeze riveting. Horizontal and vertical riveting tasks using squeeze riveting tools were performed by 16 aircraft workers wearing three different shoulder exoskeletons and a no-exoskeleton condition capturing electromyographic signals from shoulder and torso muscles. Exoskeletons reduced normalized EMG for the left anterior deltoid at both heights (6.6% and 15.7%), the right anterior deltoid (8.3%) and the right and left medial deltoid (9.3% and 8.9%) at the upper height for horizontal squeeze riveting. Exoskeletons reduced normalized EMG for the right and left anterior deltoids (7.0%-10.6%) and medial deltoids (1.3%-7.1%) within the upper zones during vertical squeeze riveting. Participants felt exoskeletons would be beneficial for squeeze riveting, however no preference was found among the exoskeletons used.

The Association Between Forceful Hand Exertions and Musculoskeletal Disorders of the Neck and Shoulder: A Prospective Cohort Study of US Manufacturing Workers

OBJECTIVE

The aim of this study was to estimate associations between biomechanical exposures and workplace neck and shoulder musculoskeletal disorders (NSMSDs) in a prospective cohort.

METHODS

Manufacturing workers (N = 349) were followed for 28 months. Biomechanical exposures were collected on each individual, and physical examinations were performed every 4 months. Prevalent cases at baseline (n = 30) were excluded from the analysis.

RESULTS

There were 18 incident cases of NSMSDs. Greater than 33% time in forceful hand exertion doubled the rate of incident NSMSDs. Greater than 18 degrees of shoulder abduction, during forceful hand exertion, increased the rate by 55%. Confidence intervals were wide.

CONCLUSIONS

Effect estimates of the relationship between forceful hand exertions and NSMSDs were consistently elevated whether measured in isolation or while in shoulder abduction. Following a larger cohort with more frequent physical examinations would improve estimates of the model.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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 (OR_adj) 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, OR_adj 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, OR_adj 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).

CONCLUSION

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.

Gender Differences in Associations between Biomechanical and Psychosocial Work Exposures and Age of Withdrawal from Paid Employment among Older Workers

BACKGROUND

Work exposures are known predictors of withdrawal from employment, but the associations between work exposures and withdrawal may vary with gender. This study evaluated gender differences in associations between biomechanical and psychosocial work exposures and age of withdrawal from paid employment among older workers in Norway.

METHODS

77,558 men and 67,773 women (born 1949-1953) were followed from age 62 until withdrawal from paid employment or end of follow-up in 2016 (up to five years follow-up). Information about eight biomechanical and seven psychosocial exposures was obtained from a gender-specific job exposure matrix. Using Cox regression, the difference in mean estimated time until withdrawal between non-exposed and exposed was calculated for each gender and work exposure separately.

RESULTS

The largest gender difference was found for high psychological demands. Among men, the non-exposed withdrew earlier than the exposed (-3.66 months (95% CI: -4.04--3.25 months)), and contrary among women (0.71 (0.28-1.10)), resulting in a gender difference of 4.37 (3.81-4.97) months. Gender differences were also found for monotonous work (4.12 (3.51-4.69) months), hands above shoulder height (2.41 (1.76-3.10) months), and high iso-strain (2.14 (1.38-2.95) months).

CONCLUSIONS

There were observed gender differences in the associations between some biomechanical and psychosocial work exposures and mean age of withdrawal from paid employment among older workers. However, the results are likely affected by the selection of who remains in the workforce at age 62 and should be interpreted accordingly.

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

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.

Risk factors for shoulder disorders among French workers: prospective cohort study

Objectives

Shoulder disorders are common in the working population. This longitudinal study aimed to explore the relationships between personal factors and occupational organisational, psychosocial, and biomechanical factors and the incidence of shoulder disorders.

Methods

A total of 3710 workers in the Pays de la Loire region (Loire Valley area, France) were randomly included by their occupational physician in the Cosali cohort between 2002 and 2005. All workers completed a self-administered questionnaire about personal factors and work exposure, and using a standardised physical examination, occupational physicians diagnosed shoulder disorders. Between 2007 and 2010, 1611 workers were re-examined by their occupational physician. The 1,320 workers free of shoulder disorders at baseline were studied. A conceptual model was developed in which relationships between organisational, psychosocial, biomechanical, and personal factors at baseline and the incidence of shoulder disorders were assumed. Structural equation modelling was used to test the model.

Results

Shoulder disorders were directly associated with biomechanical factors and age but not with psychosocial factors. However, skill discretion and psychological demand influenced shoulder disorders indirectly through biomechanical factors. Exposure to a work pace dependent on an automatic rate and to a work pace dependent on customers’ demands were associated with biomechanical and psychosocial factors, but not directly to shoulder disorders.

Conclusions

This study identified the complex direct and indirect relationships between occupational factors and shoulder disorders. Our data confirmed our conceptual causation model: organisational and psychosocial factors were associated with biomechanical factors, while biomechanical factors were associated with the incidence of shoulder disorders.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-022-01853-9.

Association between working in awkward postures, in particular overhead work, and pain in the shoulder region in the context of the 2018 BIBB/BAuA Employment Survey

Background

Musculoskeletal disorders are the leading cause of work-related sick leave and incur substantial socioeconomic costs. With the aging of our society and employees, the problem is exacerbating, and prevention is becoming increasingly important. According to previous studies, exposure to awkward postures, such as overhead work, is associated with musculoskeletal problems.

Objective

This study aimed to determine the current prevalence of employees who work in awkward postures, specifically overhead, stratified by age, gender and occupation in the context of the 2018 BIBB/BAuA Employment Survey and to analyze associations between awkward working postures, in particular overhead work, and pain in the shoulder region.

Method

The study is based on secondary data from the German 2018 BIBB/BAuA Employment Survey. We have included 14,327 of the 20,012 employees aged < 67 years who work at least 35 h per week who took part in the survey. The classification of participants in occupational groups is based on the Blossfeld classification. The multivariate analysis was conducted by applying robust Poisson regression models adjusted block by block to obtain the relation between the self-reported frequency of working in awkward postures, in particular overhead work, and the occurrence of arm pain and neck and shoulder pain. Prevalence ratios (PR) are reported as effect estimates.

Results

12.7% of participants indicated that they are often exposed to awkward postures at work; 5.0% stated they often performed overhead work. The majority of these employees worked in agricultural, unskilled and skilled manual occupations. The crude prevalence is 17.4% for arm pain and 48.4% for neck and shoulder pain. If subjects reported that they often performed overhead work, the risk of arm pain increased by 18% (PR 1.18, CI 1.04–1.34, final model).

Conclusion

Working in awkward postures, especially overhead work, is a risk factor for upper extremity musculoskeletal disorders. The development of prevention strategies should focus on the workforce in agricultural, unskilled and skilled manual occupations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04482-4.

Combined ergonomic exposures and development of musculoskeletal pain in the general working population: A prospective cohort study

Objective:

This study aimed to investigate the importance of combined ergonomic exposures at work for the development of musculoskeletal pain.

Methods:

Through four rounds (2012–2018) of the Work Environment and Health in Denmark Study, 18 905 employees of the general working population replied to a baseline and 2-year follow-up questionnaire. First, a k-means cluster analysis of seven ergonomic factors (back bending, arm above shoulders, lifting etc., from ‘never’ to ‘almost all the time’) identified nine naturally occurring clusters. Second, using a weighted survey regression model controlling for age, gender, survey year, education, lifestyle, influence at work, and pain intensity at baseline, we estimated development of pain intensity (0–10) in the neck-shoulder and low-back in these clusters. The largest cluster served as reference to the other clusters and was characterized by low ergonomic exposures.

Results:

Clusters characterized by multiple combined ergonomic exposures for a relatively high percentage of the working time showed the largest increase in neck-shoulder as well as low-back pain intensity from baseline to follow-up. However, clusters characterized by high exposure to a few specific ergonomic factors also increased pain significantly, eg, standing/walking combined with lifting/carrying or twisted/bent back for the majority of the working time increased low-back pain, whereas repetitive arm movements for the majority of the working time with or without standing/walking increased neck-shoulder pain.

Conclusion:

Combined occupational ergonomic exposures play an important role in the development of musculoskeletal pain. Workplace preventive approaches should consider this in risk assessments and organization of the work.