Association of occupational and non-occupational risk factors with the prevalence of self-reported carpal tunnel syndrome in a national survey of the working population

To compare the association of occupational versus personal, nonoccupational risk factors with the prevalence of carpal tunnel syndrome (CTS), data from the 1988 National Health Interview Survey, Occupational Health Supplement, were analyzed. When both occupational factors (bending/twisting of the hands/wrists [B/T] and use of hand-held vibrating tools) and personal nonoccupational factors (gender, race, age, body mass index [BMI], smoking, education, and family income) were included in a multivariate logistic regression model, adjusted odds ratios (AORs) of these factors for reporting medically called CTS (MC-CTS) were: exposure to B/T, 5.5; exposure to vibration, 1.9; white race, 16.7; female gender, 2.3; BMI ≥25, 2.0; history of cigarette smoking, 1.6; age ≥40, 1.2; education >12 years, 1.2; and annual family income ≥$20,000, 1.5. Although both occupational and nonoccupational factors are associated with reporting of CTS, repetitive bending/twisting of the hands/wrists and use of vibrating tools remain important risk factors for work-related carpal tunnel syndrome. Am. J. Ind. Med. 32:550–556, 1997. © 1997 Wiley-Liss, Inc.     

Prevalence and risk factors of tendinitis and related disorders of the distal upper extremity among U.S. workers: comparison to carpal tunnel syndrome

BACKGROUND: National estimates of tendinitis and related disorders of the distal upper extremity among U.S. workers have not been available with the exception of carpal tunnel syndrome. METHODS: The Occupational Health Supplement Data of the 1988 National Health Interview Survey were analyzed for tendinitis and related disorders of the hand/wrist and elbow (distal upper extremity) using the Survey Data Analysis (SUDAAN) software. RESULTS: Among the 30,074 respondents (statistically weighted population of 127 million) who had worked anytime during the previous 12 months, 0.46% (95% CI: 0.36, 0.56) reported that they experienced a "prolonged" hand discomfort which was called tendinitis, synovitis, tenosynovitis, deQuervain's disease, epicondylitis, ganglion cyst, or trigger finger, by a medical person. This corresponds to 588,000 persons (95% CI: 457,000; 712,000) reporting one of these disorders, 28% (or 164,000) of which were thought to be work-related by the medical person. Among various risk factors examined by multiple logistic regression analysis, bending/twisting of the hands/wrists at work and female gender were significantly associated with reporting of these disorders. CONCLUSIONS: By combining these cases with the previously reported cases of work-related carpal tunnel syndrome, we estimate that there were approximately 520,000 cases of work-related musculoskeletal disorders of the distal upper extremity among US workers in 1988.     

Association of Occupational and Non-occupational Risk Factors with the Prevalence of Work Related Carpal Tunnel Syndrome

PURPOSE: Several occupational and personal risk factors cause the development of carpal tunnel syndrome (CTS). The purpose of the study was to evaluate both non-occupational and occupational factors associated with CTS in industrial workers. METHODS: A cross sectional study was designed with 400 industrial workers (77% male, 23% female) randomly selected. Workers' upper extremities were examined and related signs and symptoms were assessed. Questionnaires about personal and occupational risk factors were completed and suspicious cases were referred for NCV (nerve conduction velocity) testing and documentation of diagnosis. RESULTS: About 395 workers from automobile industry factories in Iran were assessed by interview and electrodiagnostic studies. Among 395 workers, 47 met the definition of CTS to yield a prevalence of 11.9%. These 47 workers averaged 29.85 years of age (SD = 6.28), and the mean age of the healthy group was 27.95 (SD = 4.86). 395 workers included 91 women (23%) and 304 men (77%). Using multivariate logistic regression model the largest adjusted odds ratios of personal and occupational factors for CTS were: exertion of force over one kilogram 6.38 (1.91-2.02); bending/twisting of the hands/wrists > 30 degrees , 5.62 (0.56-55.6); history of cigarette smoking 4.68 (1.80-11.80); rapid movement of hands 4.44 (1.41-14.02); and use of vibrating tools 3.23 (1.46-7.15). CONCLUSION: Some occupational factors including force exertion, bending/twisting of the hands, rapid movement of the hands and vibration are associated with CTS.     

The US prevalence of self-reported carpal tunnel syndrome: 1988 National Health Interview Survey data.

To estimate the prevalence of carpal tunnel syndrome among US adults, data from the Occupational Health Supplement of the 1988 National Health Interview Survey were analyzed. Based on a sample of 44,233 households (response rate, 91.5%), an estimated 1.55% (2.65 million) of 170 million adults self-reported carpal tunnel syndrome in 1988. Females and Whites had a higher prevalence of self-reporting carpal tunnel syndrome than males and non-Whites, respectively. Among 127 million adults who worked during the 12 months before the survey, 0.53% (0.68 million) reported that their "prolonged" hand discomfort was called carpal tunnel syndrome by a health care provider.     

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.     

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.     

Self-reported hand and wrist arthritis and occupation: data from the U.S. National Health Interview Survey-Occupational Health Supplement

BACKGROUND: There is a paucity of population-based studies examining occupational hand-wrist arthritis. We examined relationships between hand-wrist arthritis, occupation, and biomechanical exposures in the U.S. National Health Interview Survey-Occupational Health Supplement. METHODS: A randomized, multi-stage, and cross-sectional national prevalence survey was carried out. RESULTS: Self-reported, medically attended hand-wrist arthritis was common among employed persons (period prevalence 1.58%; lifetime prevalence 3.58%). Highest prevalences occurred among technicians, machine operators, assemblers, and farmers, and in the mining, agriculture, and construction industries. Work requiring repetitive hand bending and twisting was associated with hand-wrist arthritis (Odds Ratio 1.43; 95%CI: 1.11-1.84; P = 0.005). Among workers with hand arthritis, 7.4% had made major changes in their work, 7.6% missed work, and 4.5% stopped working or changed jobs because of the problem. CONCLUSIONS: Our study links hand-wrist arthritis to occupation and potentially modifiable workplace ergonomic factors. The spectrum of hand-wrist "cumulative trauma" disorders may considerably exceed that of soft-tissue injuries like carpal tunnel syndrome and tendonitis, and may include arthritis, a widely prevalent, disabling condition.     

Carpal tunnel syndrome in repetitive work: a follow-up study

BACKGROUND: The Project on Research and Intervention in Monotonous work (PRIM) studied Danish workers for 3-4 years to determine the effects of monotonous work. The present study is a subset of that cohort and compares prevalence and incidence differences of carpal tunnel syndrome (CTS) between workers with highly repetitive work tasks and workers with varied work tasks. METHODS: The baseline study included 731 participants. Follow-up examinations were performed after 6 and 18 months. The CTS diagnosis was based on symptom interviews and nerve conduction tests. The repetitiveness levels were determined with electrogoniometers and observation of cycle times. RESULTS: The overall prevalence of CTS was 1.6% on the working hand and 0.7% on the other hand. There was a significantly increased risk of CTS for every 10-hr increase of repetitive non-forceful work (OR = 1.84; 95% CI = 1.06-3.19) on the working hand. This result, however, was based on few cases and a low prevalence in the control group. The overall annual CTS incidence was 0.62% on the working hand and 0.44% on the other hand. For the repetitive work tasks, the mean power frequencies ranged from 0.53 to 0.79 Hz. CONCLUSIONS: In the baseline study, highly repetitive work was associated with CTS. The CTS incidence was too low to perform any analyses of exposure differences.     

Workplace surveillance for carpal tunnel syndrome using hand diagrams

Four hundred and eleven workers from 4 different companies participated in a worksite screening program designed, in part, to estimate the prevalence of carpal tunnel syndrome (CTS). Each worker completed a discomfort survey and underwent limited nerve conduction testing of the median and ulnar sensory nerves in both wrists. The discomfort survey included a hand diagram which allowed subjects to shade in area(s) affected by numbness, burning, tingling, or pain. The discomfort survey also asked each worker to indicate whether she or he had experienced neuropathic symptoms (i.e., numbness, burning, tingling, or pain) in the wrist, hand or fingers of each hand, without regard to localization (i.e., median versus ulnar versus radial distribution), and also nocturnal occurrence of symptoms. Analyses involved comparing hand diagram scores and non localized wrist/hand/finger symptoms with electrodiagnostic test results. All configurations of hand diagram scores of the dominant hands had a statistically significant association with electrophysiologically determined median nerve dysfunction, but so did non localized symptom reports. The sensitivity, specificity, and positive predicted values of hand diagrams were poorer than those reported previously. While some test performance characteristics of hand diagrams were better than those for non localized distal extremity symptoms consistent with CTS, some were worse. Overall, our data suggest that hand diagrams are no better than using a questionnaire to determine if workers have experienced symptoms consistent with CTS in their wrists, hands or fingers without regard to localization. The choice of screening tool would depend on the goal of screening, in particular, whether it is more desirable to have slightly higher sensitivity or positive predictive value.     

Worksite and Personal Factors Associated with Carpal Tunnel Syndrome in an Egyptian Electronics Assembly Factory

Abstract

The study objective was to identify personal and work related risk factors associated with carpal tunnel syndrome (CTS) in electronics assembly operators relative to clerical workers in the same factory. Of 422 workers in a television assembly factory located in Ismailia, Suez Canal Area, Egypt, 198 (46.9%) participated. The electronics assembly workers were more likely to report CTS (odds ratio = 11.41, 95% CI = 3.6?40.26) than were the clerical workers. The significant risk factors were longer work years (odds ratio = 1.11, 95% CI = 1.03?1.20) and precision-type hand grip (odds ratio = 6.5, 95% CI = 1.08-39.23). The results suggest an association between electronics assembly and CTS. Work years and precision grip are possible risk factors for CTS and should be studied more thoroughly. Tools to reduce the need for precision grip may help reduce CTS.     

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.     

Validation of a surveillance case definition of carpal tunnel syndrome

The National Institute for Occupational Safety and Health (NIOSH) has proposed a surveillance case definition for work-related carpal tunnel syndrome (CTS). The case definition requires the presence of median nerve symptoms; one or more occupational risk factors; and objective evidence of CTS including one of three physical examination findings or nerve conduction tests diagnostic of CTS. We evaluated the performance of the NIOSH case definition, restricting our analysis to cases in which physical examination findings served as the objective criterion. Nerve conduction studies were used as the gold standard. Seventy-eight workers were studied; 38 percent had CTS. The NIOSH case definition had sensitivity of 0.67 (95% CI = 0.57, 0.77), specificity of 0.58 (95% CI = 0.47, 0.69), and positive and negative predictive values of 0.50 (95% CI = 0.39, 0.61) and 0.74 (95% CI = 0.64, 0.84), respectively. Overall 38 percent of subjects were classified incorrectly. In a sample with a prevalence of 15 percent, as might be encountered in high risk workplaces, the positive predictive value would be 0.22. In conclusion, when physical examination findings serve as the objective criterion the performance of the case definition is modest reflecting the limited diagnostic value of its component tests and indicating that effective screening for CTS awaits improved diagnostic techniques.     

Prevalence of musculoskeletal disorders in union ironworkers

The prevalence of musculoskeletal disorder (MSD) symptoms and doctor-diagnosed musculoskeletal disorders (DDMDs) were estimated among union construction ironworkers by a telephone-administered questionnaire. Of 1996 ironworkers eligible, 1566 were contacted and 981 were interviewed. The prevalence of self-reported MSD symptoms was high for the lower back (56%), wrist/hands/fingers (40%), knees (39%), and shoulders (36%). The most common DDMDs were tendonitis (19%), ruptured disk in the back (18%), bursitis in the shoulder (15%), and carpal tunnel syndrome (12%). Generally, the prevalence of DDMDs and MSD symptoms increased with duration of employment. In age-adjusted logistic regression analyses, those who worked 25 to 35 years were more likely to have tendonitis (odds ratio [OR] 7.1, 95% confidence interval [CI] 3.116.6), shoulder bursitis (OR 13.7, 95% CI 3.160.4), knee bursitis (OR 5.1, 95% CI 1.025.1), and ruptured intervertebral back disk (OR 6.7, 95% CI 2.617.5). The effect of prior injury was also consistently high (upper extremities, OR 4.6; lower extremities OR 5.1; lower back, OR 6.0). Among workers without prior injuries, MSD symptoms were more frequent for the lower back in structural ironwork (OR 1.7, 95% CI 1.12.6), and for the upper extremity in concrete reinforcement ironwork (OR 1.9, 95% CI 1.22.9). These findings suggest that some musculoskeletal morbidity in construction ironworkers may be work related and thus preventable.     

Soft tissue disorders in the upper limbs of female garment workers

In this cross-sectional investigation of female garment workers the prevalence of soft tissue disorders of the hands and arms was studied. The findings were compared with the prevalence of disorders in a group of female hospital employees not required to use repetitive hand motion. One hundred and eighty-eight garment workers and 76 hospital employees were surveyed by questionnaire and physical examination. The prevalences of persistent shoulder, wrist, and hand pain were significantly greater among the garment workers (rate ratio 2, 4, and 3, respectively). In both groups about 60% of the persistent hand pain was consistent with carpal tunnel syndrome (rate ratio 3). These associations held when the comparisons were stratified by age and by length of employment. Workers whose native language was not English were significantly less likely to report symptoms (rate ratio 0.6). Workers in hand sewing and trimming suffered especially high prevalences of persistent pain in all upper limb sites. Stitchers had elevated rates of pain in the shoulders, wrists, and hands. Workers ironing by hand had a significant elevation in elbow pain rates. Garment assembly tasks appear to be associated with cumulative trauma of the hands and wrists; the biomechanical features of these jobs should be studied in greater detail.     

Worksite and personal factors associated with carpal tunnel syndrome in an Egyptian electronics assembly factory

The study objective was to identify personal and work-related risk factors associated with carpal tunnel syndrome (CTS) in electronics assembly, operators relative to clerical workers in the same factory. Of 422 workers in a television assembly factory located in Ismailia, Suez Canal Area, Egypt, 198 (46.9%) participated. The electronics assembly workers were more likely to report CTS (odds ratio = 11.41, 95% CI = 3.6 -40.26) than were the clerical workers. The significant risk factors were longer work years (odds ratio = 1.11, 95% CI = 1.03-1.20) and precision-type hand grip (odds ratio = 6.5, 95% CI = 1.08-39.23). The results suggest an association between electronics assembly and CTS. Work years and precision grip are possible risk factors for CTS and should be studied more thoroughly. Tools to reduce the need for precision grip may help reduce CTS.     

Cross-sectional study of the relationship between repetitive work and the prevalence of upper limb musculoskeletal disorders.

BACKGROUND: This study examined the relationship of repetitive work and other physical stressors to prevalence of upper limb discomfort, tendinitis, and carpal tunnel syndrome. METHODS: Three hundred fifty-two workers from three companies participated. Job exposure levels for repetition and other physical stressors were quantified using an observational rating technique. Ergonomic exposures were rated on a 10-point scale, where 0 corresponded to no stress and 10 corresponded to maximum stress. Job selection was based on repetition (three categories: high, medium, and low) to ensure a wide range of exposures. Physical evaluations on all participating workers were performed by medical professionals and included a self-administered questionnaire, physical exam, and limited electrodiagnostic testing. RESULTS: Repetitiveness of work was found to be significantly associated with prevalence of reported discomfort in the wrist, hand, or fingers (odds ratio (OR) = 1.17 per unit of repetition; OR = 2.45 for high vs. low repetition), tendinitis in the distal upper extremity (OR = 1.23 per unit of repetition; OR = 3.23 for high vs. low repetition), and symptoms consistent with carpal tunnel syndrome (OR = 1.16 per unit of repetition; OR = 2.32 for high vs. low repetition). An association was also found between repetitiveness of work and carpal tunnel syndrome, indicated by the combination of positive electrodiagnostic results and symptoms consistent with carpal tunnel syndrome (OR = 1. 22 per unit of repetition; OR = 3.11 for high vs. low repetition). CONCLUSIONS: These findings indicate that repetitive work is related to upper limb discomfort, tendinitis, and carpal tunnel syndrome in workers. Further research with a wider range of exposures is needed to evaluate the effects of other physical stresses alone and in combination.     

Prevalence of abnormal median nerve conduction in applicants for industrial jobs

There has been much debate regarding the work relatedness of carpal tunnel syndrome (CTS) and whether workers diagnosed with CTS had pre-existing disease at the time they were hired. To elucidate the latter issue, we examined the prevalence of abnormal median nerve conduction within the carpal tunnel in applicants for industrial jobs. Nerve conduction studies (NCS) were performed on both hands of 1,021 applicants following a conditional offer of employment. Each applicant completed a self-administered symptom survey specific to the upper extremity. Applicants had worked previously for an average of 4.4 (range 0–33) years and had a mean age of 30.1 (S.D. 8.9) years. Nerve conduction studies were performed in a private medical clinic. Sensory palmar latencies were determined over an 8 cm segment for the median and ulnar nerves. The difference between the median and ulnar sensory latencies was the primary electrophysiologic measurement used to determine median neuropathy. Using a very conservative criterion for abnormal median nerve conduction, 17.5% of the applicants were classified with neuropathy in at least one hand. Despite the relatively high prevalence of median neuropathy, relatively few (10%) with positive NCS acknowledged symptoms associated with CTS. Males had a higher percentage of median neuropathy than did females. We conclude that a large percentage of industrial workers have objective evidence of abnormal median nerve conduction within the carpal tunnel when hired. The high prevalence of abnormal median nerve conduction without corresponding symptoms may suggest a subclinical entity associated with CTS. © 1996 Wiley-Liss, Inc.     

Carpal tunnel syndrome in vibration disease.

The presence of carpal tunnel syndrome (CTS) in 125 forestry workers with exposure to vibration was examined clinically by electromyography and by determining vibration detection thresholds. Numbness of the hands was present in 43%, history of diminished hand muscle force in 15%, and Raynaud's phenomenon in 27%. The muscle weakness correlated significantly with motor nerve conduction velocity in the median nerve in both hands. In 25 forestry workers CTS was diagnosed. The condition was bilateral in 48%; otherwise it was more common on the right side. Fifteen patients were referred for surgery but because of spontaneous recovery or refusal by the patients only five underwent surgery; of these four improved. The motor conduction velocity of the ulnar nerve was decreased among patients with CTS supporting the idea that entrapment neuropathies in the hands may be due to tissue swelling caused by vibration at work. Total exposure time to vibration correlated with the decrease in motor conduction velocity in the ulnar nerve.     

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.