Self-reported workplace related ergonomic conditions as prognostic factors for musculoskeletal symptoms: the "BIT" follow up study on office workers

Aims: To identify prognostic ergonomic and work technique factors for musculoskeletal symptoms among office workers and in a subgroup with highly monotonous repetitive computer work. Methods: A baseline questionnaire was delivered to 5033 office workers in 11 Danish companies in the first months of 1999, and a follow up questionnaire was mailed in the last months of 2000 to 3361 respondents. A subgroup with highly monotonous repetitive computer work was formed including those that were repeating the same movements and/or tasks for at least 75% of the work time. The questionnaire contained questions on ergonomic factors and factors related to work technique. The outcome variables were based on the frequency of musculoskeletal symptoms during the last 12 months. Logistic regression analyses were used to identify prognostic factors for symptoms in the three body regions. Results: In total, 39%, 47%, and 51% of the symptomatic subjects had a reduced frequency of symptom days in the neck/shoulder, low back, or elbow/hand region, respectively. In all regions more men than women had reduced symptoms. In the multivariate logistic regression analyses, working no more than 75% of the work time with the computer was a prognostic factor for musculoskeletal symptoms in the neck/shoulder and elbow/hand, and a high influence on the speed of work was a prognostic factor for symptoms in the low back. In the subgroup with highly monotonous repetitive computer work, the odds ratios of the prognostic factors were similar to those for the whole group of office workers. Conclusion: When organising computer work it is important to allow for physical variation with other work tasks, thereby avoiding working with the computer during all the work time, and further to consider the worker''s own influence on the speed of work.     

Occupational factors and carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most commonly reported nerve entrapment syndrome. The prevalence of CTS among 652 active workers in jobs with specific hand force and repetitiveness characteristics was estimated. The prevalence of CTS ranged from 0.6% among workers in low force-low repetitive jobs to 5.6% among workers in high force-high repetitive jobs. When controlling for potential confounders, the odds ratio for the high force-high repetitive jobs was more than 15 (p less than .001) compared to the low force-low repetitive jobs. High repetitiveness appears to be a greater risk factor than high force (odds ratio of 5.5 p less than .05 versus 2.9 and not statistically significant).     

Course of symptoms and median nerve conduction values in workers performing repetitive jobs at risk for carpal tunnel syndrome

BACKGROUND: Carpal tunnel syndrome (CTS) is a common occupational disorder associated with repetitive manual work. Little information exists about the possible relation between the variation of biomechanical hand/wrist exposure and the development of symptoms and median nerve conduction values. AIMS: To investigate the prevalence of CTS in a group of workers exposed to intensive use of the hands and the course of symptoms and median nerve conduction values after a period of reduced exposure to biomechanical risk factors. METHODS: CTS was assessed in assembly and non-assembly line workers by means of clinical examinations and nerve conduction studies (NCS). Ergonomic analysis was conducted for each assembly line workstation. RESULTS: Prevalence of CTS was significantly higher in assembly line workers compared to non-assembly line workers but there was a high prevalence of median nerve conduction abnormalities in both groups (60/102 hands and 40/110 hands, respectively). In a sizable proportion of both groups there was no relationship between symptoms and electrodiagnostic findings (45 hands and 48 hands in assembly and non-assembly line workers, respectively). When assembly line workers were re-examined after 2 years following a period of reduced work schedule, a significant proportion reported resolution of symptoms or had reverted to having normal NCS. CONCLUSIONS: In our study, repetitive work was associated with a higher level of CTS and abnormal NCS. These findings appeared to be reversible following a period of less repetitive work. Overall, there was generally poor correlation between symptoms and electrodiagnostic findings.     

The effects of repeated mechanical trauma in the meat industry

Meat handlers are more prone to traumatic hand lesions and wound infections than most other occupational groups. This paper deals with the carpal tunnel syndrome (CTS), which is thought to be a major occupationally related condition affecting thousands of workers engaged in repetitive hand motion tasks. The literature reveals a high prevalence of CTS among meat handlers. Additional epidemiological research is needed. Further, it is important to educate workers about the signs, symptoms, and causes of CTS.     

An ergonomics study on the evaluation of carpal tunnel syndrome among Chikan embroidery workers of West Bengal,India

Abstract

Background:

Chikan embroidery is a popular handicraft in India that involves hand-intensive stitching while seated in a static posture with the upper back curved and the head bent over the fabric. Women perform most Chikan embroidery.

Objectives:

The aim of this study was to analyze the repetitive nature of this work among female Chikan embroiderers by measuring the prevalence of upper extremity discomfort and carpal tunnel syndrome (CTS).

Methods:

The Nordic musculoskeletal questionnaire was used to analyze the extent of upper extremity pain symptomology. The repetitive nature of Chikan embroidery work was evaluated using the Assessment of Repetitive Tasks of the upper limbs tool (ART). Motor nerve conduction studies of median and ulnar nerves were performed with embroidery workers and a control group to determine the risk of CTS.

Results:

Among embroidery workers, the prevalence of wrist pain was 68% and forearm pain was 60%. The embroiderers also commonly reported Tingling and numbness in the hands and fingertips. The ART analysis found that Chikan embroidery is a highly repetitive task and nerve conduction studies showed that the embroidery workers were more likely to experience CTS than women in the control group.

Conclusions:

Chikan embroidery is a hand-intensive occupation involving repetitive use of hands and wrists and this study population is at risk of experiencing CTS. Future research should explore the potential benefits of ergonomics measures including incorporating breaks, stretching exercises, and the use of wrist splints to reduce repetitive strain and the probability of developing CTS.     

Self-reported carpal tunnel syndrome: Predictors of work disability from the National Health Interview Survey Occupational Health Supplement

The objective of this study was to identify risk factors for work disability among persons with carpal tunnel syndrome (CTS). The study was designed to analyze data from the Occupational Health Supplement of the National Health Interview Survey, a nationwide, population-based survey. Subjects included 544 survey respondents with self-report of CTS and 32,688 survey respondents without CTS, all aged 18–64 years, and with a history of labor force participation. Measurements were as follows: Dependent variables were work disability, defined either as cessation of employment without attribution of cause or, alternatively, as cessation of employment or job change specifically attributed to CTS by the survey respondent. Independent variables were ergonomic risk of work disability, defined by minutes of workplace repetitive hand and wrist bending for the most recent job held. This measure was derived from responses categorized by an occupation and industry matrix independent of CTS status. Socio-demographic and health status risk factors for work disability were based on the respondent report. The main results were as follows: Among 544 persons with CTS, 58 (11%, CI 8–13%) reported work disability specifically attributed to CTS, representing an estimated national prevalence of 240,578 persons with this limitation. Workplace ergonomic risk, measured as repetitive hand or wrist bending in the occupation and industry of last employment, was a significant factor predictive of CTS-attributed work disability (per 120 min of daily exposure, OR 1.7, CI 1.1–2.6), even after taking into account socio-demographic factors and health status. The conclusions were that work disability among persons with CTS is common. For those with CTS, working conditions characterized by repetitive bending of the hand or wrist may increase the risk of work disability associated with this condition. © 1996 Wiley-Liss, Inc.     

Carpal tunnel syndrome in male visual display terminal (VDT) workers

BACKGROUND: The association between working at a video display terminal (VDT) and development of carpal tunnel syndrome (CTS) is not well-established. The study surveyed the prevalence of CTS symptoms, explored the risk factors and evaluated the clinical application of hand diagrams, physical tests and electrodiagnosis among male VDT workers. METHODS: A cross-sectional study was performed in an information and communication technology company. Three-forty questionnaires were completed and 82 volunteers participated in the physical examination and nerve conduction study. The personal and occupational risk factors for CTS were analyzed. RESULTS: The prevalence of CTS symptoms was 3.8% among 340 subjects, while prolonged median motor distal latency (>4.2 msec) was disclosed in 3.7% of a subgroup receiving examination. Classic/probable CTS symptoms was associated with high body mass index (>28 kg/m(2), odds ratio = 4.1, P = 0.029) and moderate job seniority (3-5 years, odds ratio = 4.6, P = 0.023). Prolonged median motor distal latency was associated with older age (>35 years old). We did not observe correlation between CTS symptoms, abnormal NCS, positive Tinel's sign or Phalen's test. CONCLUSION: The prevalence of CTS symptoms was not high among the group of male VDT workers studied. Job seniority, but not specific tasks, was associated with CTS symptoms. More reliable and valid methods to quantify the ergonomic exposure are needed to establish the association of VDT tasks and CTS.     

Carpal tunnel syndrome among apprentice construction workers

BACKGROUND: In terms of lost-work time and restricted workdays, surgery, and rehabilitation, one of the most costly occupational musculoskeletal disorders is carpal tunnel syndrome (CTS). The purpose of this study was to determine the prevalence of CTS among apprentice construction workers. METHODS: This cross-sectional study included apprentices from four construction trades. Apprentices completed a self-administered questionnaire and received electrophysiologic studies assessing median nerve function across the carpal tunnel. A surveillance case definition for CTS was based on characteristic hand symptoms and the presence of median mononeuropathy across the carpal tunnel. RESULTS: Of the 1,325 eligible apprentices, 1,142 (86.2%) participated in the study. The prevalence of CTS among apprentices was 8.2%; sheet metal workers had the highest rate (9.2%). In operating engineers, the prevalence of CTS was significantly higher (OR = 6.9; 95% CI = 2.6-18.2) among the heavy equipment mechanics than the drivers of those vehicles. Body mass index, age, and self-reports of working overhead were associated with prevalent CTS. Less than 15% of the apprentices with CTS sought medical attention for their disorder. CONCLUSIONS: Many construction workers begin developing CTS before or during their apprenticeship. Few apprentices seek medical attention for hand symptoms characteristic of CTS. The results of this study indicate a public health need for the implementation of prevention strategies for CTS in the construction industry.     

Prevalence, incidence and risk factors of carpal tunnel syndrome in a large footwear factory

The study was conducted to assess the prevalence and incidence of carpal tunnel syndrome (CTS) in a large modern footwear factory and to identify factors predictive of CTS. To this end, 199 workers were examined in 1996, and 162 of them were re-examined in 1997. Ergonomic and psychosocial risk factors of CTS were assessed by workpost analysis and self-administered questionnaire. The prevalence of CTS at baseline in 1996 and in 1997 was 16.6% (95%CI: 11.4-21.7) and 11.7% (95%CI: 6.7-16.8), respectively. The incidence rate of CTS in 1997 was 11.7% (95%CI: 6.7-7.8). No specific type of job performance was associated with CTS. Obesity (OR = 4.4; 95%CI: 1.1-17.1) and psychological distress at baseline (OR = 4.3; 95%CI: 1.0-18.6) were strongly predictive of CTS. Rapid trigger movements of the fingers were also predictive of CTS (OR = 3.8; 95%CI: 1.0-17.2). A strict control of thework by superiors was negatively associatedwith CTS (OR = 0.5; 95%CI: 0.2-1.3). The prevalence and incidence of CTS in this workforce were largely higher than in the general population and numerous industries. The study highlights the role of psychological distress in workers exposed to a high level of physical exposure and psychological demand.     

Carpal tunnel syndrome among grocery store workers

The California Department of Health Services evaluated carpal tunnel syndrome (CTS), a median nerve entrapment condition associated with forceful and repetitive wrist motion, among grocery store workers at a large California supermarket where a CTS cluster had been reported. Forceful and repetitive wrist motion was measured, in three exposure levels, through a job classification scheme based upon type of work tasks and average time per week spent performing these tasks. A medical questionnaire and measurements of median sensory nerve conduction were used to measure CTS. CTS prevalence was 23% based upon a sample of 56 participants drawn from a workforce of 69 employees. A relative risk of 8.3 (95% confidence interval 2.6–26.4) for a history of CTS-like symptoms between the high and low exposure level groups held up after adjustment for the potential confounders of age, sex, alcohol consumption, and high-risk medical history. It was concluded that the basic principles of good ergonomic design should be used to prevent or diminish the risk of musculoskeletal injury in the workplace. © 1994 Wiley-Liss, Inc.     

An ergonomics study on the evaluation of carpal tunnel syndrome among Chikan embroidery workers of West Bengal,India

Background:

Chikan embroidery is a popular handicraft in India that involves hand-intensive stitching while seated in a static posture with the upper back curved and the head bent over the fabric. Women perform most Chikan embroidery.

Objectives:

The aim of this study was to analyze the repetitive nature of this work among female Chikan embroiderers by measuring the prevalence of upper extremity discomfort and carpal tunnel syndrome (CTS).

Methods:

The Nordic musculoskeletal questionnaire was used to analyze the extent of upper extremity pain symptomology. The repetitive nature of Chikan embroidery work was evaluated using the Assessment of Repetitive Tasks of the upper limbs tool (ART). Motor nerve conduction studies of median and ulnar nerves were performed with embroidery workers and a control group to determine the risk of CTS.

Results:

Among embroidery workers, the prevalence of wrist pain was 68% and forearm pain was 60%. The embroiderers also commonly reported Tingling and numbness in the hands and fingertips. The ART analysis found that Chikan embroidery is a highly repetitive task and nerve conduction studies showed that the embroidery workers were more likely to experience CTS than women in the control group.

Conclusions:

Chikan embroidery is a hand-intensive occupation involving repetitive use of hands and wrists and this study population is at risk of experiencing CTS. Future research should explore the potential benefits of ergonomics measures including incorporating breaks, stretching exercises, and the use of wrist splints to reduce repetitive strain and the probability of developing CTS.     

A Longitudinal Study of Industrial and Clerical Workers: Incidence of Carpal Tunnel Syndrome and Assessment of Risk Factors

This study followed workers over an extended period of time to identify factors which may influence the onset of Carpal Tunnel Syndrome (CTS). The purpose was to evaluate incidence of CTS and to create a predictive model of factors that play a role in the development of CTS. This prospective study followed 432 industrial and clerical workers over 5.4 years. Incident cases were defined as workers who had no prior history of CTS at baseline testing and were diagnosed with CTS during the follow-up period or at the follow-up screening. On the basis of logistic regression, significant predictors for CTS include baseline median-ulnar peak latency difference, a history of wrist/hand/finger tendonitis, a history of numbness, tingling, burning, and/or pain in the hand, and work above the action level of the peak force and hand activity level threshold limit value. This longitudinal study supports findings from previous cross-sectional studies identifying both work related ergonomic stressors and physical factors as independent risk factors for CTS.     

Prevalence and Work-Relatedness of Self-Reported Carpal Tunnel Syndrome Among U.S. Workers: Analysis of the Occupational Health Supplement Data of 1988 National Health Interview Survey

To estimate the prevalence and work-relatedness of self-reported carpal tunnel syndrome (CTS) among U.S. workers, data from the Occupational Health Supplement of 1988 National Health Interview Survey (NHIS) were analyzed. Among 127 million “recent workers” who worked during the 12 months prior to the survey, 1.47% (95% CI: 1.30; 1.65), or 1.87 million self-reported CTS, and 0.53% (95% CI: 0.42; 0.65), or 675,000, stated that their prolonged hand discomfort was called CTS by a medical person. Occupations with the highest prevalence of self-reported CTS were mail service, health care, construction, and assembly and fabrication. Industries with the highest prevalence were food products, repair services, transportation, and construction. The risk factor most strongly associated with medically called CTS was exposure to repetitive bending/ twisting of the hands/wrists at work (OR = 5.2), followed by race (OR = 4.2; whites higher than nonwhites), gender (OR = 2.2; females higher than males), use of vibrating hand tools (OR = 1.8), and age (OR = 1.03; risk increasing per year). This result is consistent with previous reports in that repeated bending/twisting of the hands and wrists during manual work is etiologically related to occupational carpal tunnel syndrome.     

Incidence of carpal tunnel syndrome among automobile assembly workers and assessment of risk factors

OBJECTIVES: This study defined the incidence rate of carpal tunnel syndrome (CTS) among active assembly workers and evaluated risk factors. METHODS: This study followed 189 automobile assembly workers over 1 year. Incident cases were defined as workers who had no current or prior history of CTS and were subsequently diagnosed with CTS by means of active surveillance during the study. RESULTS: The estimated annual incidence rate ranged from 1% to 10%, depending on the case definition. Significant predictors for CTS include a higher baseline median-ulnar peak latency difference, history of wrist/hand/finger tendonitis, history of diabetes, nonneutral wrist and elbow postures, and a lower self-reported social support. CONCLUSIONS: This is similar to other prospective studies that demonstrate both ergonomic and medical history are independent risk factors for development of CTS.     

职业因素对汽车制造业工人肌肉骨骼疾患影响的研究

目的了解作业场所职业病危害因素与工效学危险因素等对工人几个主要身体部位肌肉骨骼疾患（MSDs）的影响。方法选取南方3家汽车生产制造企业,采用分层、整群抽样的方法,随机从冲压、焊装、涂装、总装、树脂、质检等生产部门中抽取1个班组的生产工人作为调查对象,对其进行问卷调查,收集个人一般情况、职业病危害因素接触情况、典型不良劳动姿势与活动的暴露情况及肩臂部、手部、下背部的阳性症状。影响肌肉骨骼症状发生的单因素分析采用X^2检验,多因素分析采用logistic回归。结果共调查794名工人,其中男性765人,女性29人,平均年龄为（23．34±4．52）岁,工龄中位数2年,其文化程度以中专及以上为主（97．8％）。车企工人总体的MSDs年患率分别为下背部47．0％、肩臂部42．9％、手腕／手掌41．3％。不同工种间不同身体部位MSDs的年患率的差异均有统计学意义（均P〈0．01）,其中肩臂部、手彬手掌的年患率以焊装工的最高,下背部的年患率以总装工的最高。多因素分析结果显示,背前屈〉30°的工作（OR=1．691）等2项与下背部阳性症状年患率有关,手部高力量大角度屈伸的上肢重复活动（OR=1．685）等3项与肩臂阳性症状年患率有关,手部高力量高度重复活动（OR=1．956）等4项与手腕／手掌的阳性症状年患率有关。结论被调查的汽车制造企业工人下背部、肩臂部、手部3个身体部位MSDs的患病情况较突出,各部位的MSDs年患率主要与不良的工作姿势、活动及搬举负荷强度等工效学不良因素有关,需针对其采取有效的控制措施。     

Carpal tunnel syndrome among milking parlor workers in Northern Italy: a comparison of screening approaches

Background:Occupational tasks characterized by repetitive, awkward and forceful movements of the hand and wrist may heighten the risk of carpal tunnel syndrome (CTS) among dairy parlor workers. Median nerve impairment can be investigated with ultrasonography (US) and nerve conduction studies (NCS) but a structured questionnaire may help identify early symptoms.Objectives:Our objectives were to: a) compare the sensitivity of US investigations and NCS to detect early signs of CTS; b) explore the correlation of the results of these two tests with CTS symptoms obtained from the administration of a targeted questionnaire.Methods:Forty male milking parlor workers were recruited. The study protocol included: 1) the identification of characteristic CTS symptoms through a targeted questionnaire; 2) US imaging of the carpal tunnel inlet (using a portable ultrasound device; 3) NCS of the distal median nerve.Results:The symptom questionnaire was considered positive if at least one CTS symptom was present within two weeks prior to the examination. The symptom questionnaire showed a high level of specificity (92,6%) and sensitivity (61%) when compared with NCS results. Ultrasound results revealed a prevalence of median neuropathy of 55%, but when compared to NCS, the ultrasound showed quite low predictive values (NPV of 37% and PPV of 38%).Discussion:The symptom questionnaire was associated with the median nerve pathology often seen in CTS. Moreover, the study results have shown the questionnaire to be the most effective screening method when compared to ultrasound.Key words: Wrist, biomechanical overload, carpal tunnel syndrome     

Fish processing work: the impact of two sex dependent exposure profiles on musculoskeletal health

OBJECTIVES: To evaluate the impact of work tasks, physical exposure, and psychosocial factors on the risk of musculoskeletal disorders in men and women, in a defined industrial setting. METHODS: 116 male and 206 female fish industry workers were compared with 129 men and 208 women with more varied work. Physical and psychosocial work load as well as musculoskeletal complaints were recorded by a questionnaire. A physical examination was performed and an observation method was used for work evaluation. 196 male and 322 female former fish processing workers received a postal questionnaire. RESULTS: The women workers in the fish industry had worse working conditions than the men for repetitiveness, constrained neck postures, and psychosocial work environment. They also had higher prevalences of complaints of the neck and shoulder (prevalence odds ratio (POR) 1.9; 95% confidence interval (95% CI) 1.1 to 3.2), neck and shoulder and elbow and hand complaints (POR 2.9; 95% CI 1.8 to 4.7 and POR 2.8; 95% CI 1.6 to 4.7, respectively). The women more often than the men left the industry because of neck and upper limb complaints. Also, women in other work had a higher prevalence of complaints of the neck and shoulder (POR 2.3; 95% CI 1.1 to 5.1) than the men. The men in the fish processing industry had a higher prevalence of complaints of the neck and shoulder than the men in other work (POR 3.6; 95% CI 1.6 to 8.0). This difference was not shown up by the questionnaire. CONCLUSIONS: Despite superficially similar work, there were clear sex differences in physical exposure and psychosocial work environment. Work in the fish processing industry was associated with a high risk of neck and upper limb disorders in women, which was probably mainly due to their extremely repetitive work tasks; the corresponding men had less repetitive work and less disorders. Also, a healthy worker effect on neck and upper limb disorders was found. The advantage of a physical examination compared with a questionnaire is clearly shown.

 

     

Impact of occupations and job tasks on the prevalence of carpal tunnel syndrome.

In this investigation reported epidemiologic studies on carpal tunnel syndrome (CTS) (15 cross-sectional studies involving 32 occupational or exposure groups and six case-referent studies) were reviewed. The prevalence of CTS in the different occupational groups varied between 0.6 and 61%. The highest prevalence was noted for grinders, butchers, grocery store workers, frozen food factory workers, platers, and workers with high-force, high-repetitive manual movements. Odds ratios greater than 10 were reported for exposed groups in three studies. On the basis of epidemiologic and other evidence, it was concluded that exposure to physical work load factors, such as repetitive and forceful gripping, is probably a major risk factor for CTS in several types of worker populations. At least 50%, and as much as 90%, of all of the CTS cases in these exposed populations appeared to be attributable to physical work load.     

Carpal tunnel syndrome and work organisation in repetitive work: a cross sectional study in France. Study Group on Repetitive Work

OBJECTIVES: To study the determinants of signs of carpal tunnel syndrome (CTS) in repetitive industrial work, with special attention to occupational constraints at group level and management practices of the companies. METHOD: A cross sectional study was conducted in three sectors: assembly line; clothing and shoe industry; food industry. A total of 1210 workers in repetitive work, from 53 different companies, was compared with a control group of 337 workers. Constraints at the workplace were partly self declared, and partly assessed by the occupational physicians in charge of the employees of the company. The definition of CTS was based on a standardised clinical examination. RESULTS: CTS was associated with repetitive work, especially packaging. It was more frequent among subjects who declared psychological and psychosomatic problems and those with a body mass index > or = 27. Dissatisfaction with work, lack of job control, short cycle time, and having to press repeatedly with the hand were associated with the syndrome. An odds ratio (OR) of 2.24 was found for "just in time" production. CONCLUSION: The results emphasise the complexity of the determinants of CTS, the role of psychosocial factors at work and the potentially negative effects of some practices of the companies aimed at enhancing their competitiveness.

 

     

Musculoskeletal disorders among construction apprentices in Hungary.

The purpose of this study was to determine the prevalence of occupationally related musculoskeletal disorder (MSD) symptoms and carpal tunnel syndrome (CTS) among construction apprentices in Hungary. Symptoms of occupational MSDs and the job factors contributing to the symptoms were determined through an administered symptom and job factors survey. The prevalence of CTS was based on a case definition that included hand symptoms and nerve conduction studies of the median nerve across the carpal tunnel. The participation rate was 96% among the 201 eligible construction apprentices. More than 50% of the apprentices reported occupationally related musculoskeletal symptoms in the previous 12 months. Job tasks that required awkward postures and working in a static position were the two factors that contributed most to MSD symptoms. No cases of CTS were found in this sample of apprentices. Although disorders of the musculoskeletal system are more prevalent among experienced construction workers, this study indicated that symptoms of MSDs are present among young construction workers. Assessing the magnitude and nature of occupational related MSDs is the first step in promoting a healthier, safer, and more efficient workforce.