A cross-sectional study of musculoskeletal symptoms and risk factors in semiconductor workers

The prevalence and risk factors of work related musculoskeletal disorders among electronics manufacturing workers: a cross-sectional analytical study in China

OBJECTIVES

To describe the prevalence of self-reported musculoskeletal disorders among workers in the electronics manufacturing industry and to investigate the relations between work-related musculoskeletal disorders (WMSDs) and work-related variables.

METHODS

An interview-based questionnaire survey was carried out in thirty electronics manufacturing factories in China in 2018. The prevalence of WMSDs was estimated using the modified Nordic Musculoskeletal Questionnaire (NMQ). A multivariate logistic regression model was applied to evaluate the effects of risk factors on WMSDs on multiple body parts.

RESULTS

The 12-month prevalence of WMSDs among participants was 40.6%, and the common body sites affected were the neck (26.8%), shoulder (22.8%), upper back (14.9%), and lower back (14.8%). The results of logistic regression showed that female adults, > 5 job tenure and work-related factors (including awkward posture, lifting or carrying weights, excessive repetition, prolonged sitting, monotonous work and working under conditions of cold or temperature variations) led to a higher risk of WMSDs on most body parts. Upper back, wrist/hand and elbow pain levels were significantly higher for workers with vibration. However, more frequently, physical exercise was a protective factor against WMSDs on most body parts except the upper back, leg and knee.

CONCLUSIONS

The study indicates a high prevalence of musculoskeletal pain among the electronics manufacturing industry in China. Different personal and work factors are related to the occurrence of WMSD on different body parts. Preventive measures should be implemented based on the characteristics of WMSD in the electronic manufacturing industry. Furthermore, the training and intervention guidance of ergonomic hazards in the workplace need to be strengthened by understanding the impact of bad posture, avoiding long-term sitting posture and increasing physical activities.

Semiconductor Work, Leukemia, and Cancer Risk: A Systematic Review and Meta-Analysis

BACKGROUND

With the development of the semiconductor industry over the past 60 years, various occupational diseases have been reported to coincide with rapid industrial growth. Among these occupational diseases, the association between semiconductor work and cancers, including leukemia, remains controversial. Therefore, this systematic review and meta-analysis assesses the associations between semiconductor work, leukemia, and cancer risk.

METHODS

The core research databases, including PubMed, were screened for studies published until 31 July 2022. All eligible studies assessed cancer risk among workers in the semiconductor industry.

RESULTS

Nine studies were selected after a literature review. The employment period of semiconductor workers in each study was between 1965 and 2009. Semiconductor work was not significantly associated with the risk of leukemia (Relative Risk [RR], 1.02; 95% Confidence Interval [CI], 0.74-1.41) or cancer (RR, 1.00; 95% CI, 0.93-1.07).

CONCLUSION

In this meta-analysis, semiconductor work was not significantly associated with leukemia or cancer risk. Internal comparisons, such as non-fab workers, quality of the study, employment period, and healthy worker effect, should be considered for interpretation. Furthermore, a prospective cohort study based on overall semiconductor workers in the industry could be useful to assess occupational disease risk as a mandatory component of health assessment.

Biological Assessment of Potential Exposure to Occupational Substances in Current Semiconductor Workers with at Least 5 Years of Employment

Background: this study aimed to conduct a biological assessment of the potential exposure to carcinogenic substances in current semiconductor workers. Methods: A cross-sectional study was conducted on 306 semiconductor workers. The assessed biomarkers were as follows: (benzene) urine S-phenylmercapturic, trans,trans-muconic acid, blood benzene; (trichloroethylene) urine trichloroacetic acid; (2-ethoxyethanol) 2-ethoxyacetic acid; (arsine) urine arsenic3+, arsenic5+, monomethylarsonic, dimethylarsinic acid, arsenobetaine; (shift work) 6-hydroxymelatonin; (smoking) cotinine, and (radiation). The detection rate of these materials is defined as more than the biological exposure index (BEI) or the previous reference value. Results: Some workers exposed to trans,trans-muconic acid, trichloroacetic acid, and arsenic5+ showed high BEI levels. Generally, there was no difference according to job categories, and workers were suspected to be exposed to other sources. The melatonin concentration tended to decrease when working at night, and cotinine was identified as an excellent surrogate marker for smoking. In the case of radiation exposure, there was no significant difference in the number of stable chromosome translocation in 19 semiconductor workers. Their estimated radiation exposure level was below the limit of detection (LOD) or near the LOD level. Conclusion: In this study, most carcinogens were below the BEI level, but verification through re-measurement was needed for workers who were identified to have a high BEI level. For continuous monitoring, a prospective cohort is necessary to deal with the healthy worker effect and assess additional materials.

Work-related and personal factors in shoulder disorders among electronics workers: findings from an electronics enterprise in Taiwan

BACKGROUND

The electronics industry is one of the largest global industries, and significant numbers of workers are engaged in this industry. Evidence suggests two associations, including one between ergonomic risks and shoulder disorders and another between psychological stress and psychological problems among workers in this industry. Investigations on ergonomic risks, psychological stress, and sex effects for shoulder disorders in this industry are limited. This study aimed to explore personal and work-related factors associated with shoulder disorders and to investigate the combined effect of similar ergonomic risk factors.

METHODS

In this cross-sectional study, 931 workers aged 20 to 58 from an electronics factory in Taiwan were recruited. A Nordic musculoskeletal questionnaire was used to assess shoulder symptoms. Sociodemographic factors and work-related factors, including psychological stress, were assessed. One hundred random sample workers with shoulder symptoms underwent a standardized clinical test for the evaluation of subacromial impingement syndrome. The ergonomic risks were assessed by the risk filter of 'upper limb disorders in the workplace', including repetition, posture, force, vibration, and duration of exposure.

RESULTS

The prevalence of shoulder symptoms was 30.5, and 19% of those with shoulder symptoms had subacromial impingement syndrome. In multivariable analyses, older age (adjusted odds ratio (aOR) = 1.37, 95% CI 1.01-1.86), repetition (aOR = 1.73, 95% CI 1.15-2.60) and posture (aOR = 1.85, 95% CI 1.10-3.11) were associated with shoulder symptoms. Regarding the gender effect, older age (aOR = 1.46, 95% CI 1.01-2.11), repetition (aOR = 1.64, 95% CI 1.00-2.68), posture (aOR = 1.89, 95% CI 1.01-3.52), and force (aOR = 1.68, 95% CI 0.99-2.85) were associated with shoulder symptoms in men, whereas posture (aOR = 2.12, 95% CI 0.99-4.57) was associated with symptoms in women.

CONCLUSIONS

This study implies that repetition and posture are important risk factors for shoulder disorders in the electronics industry. The risk exhibited sex differences, and force was more important for shoulder disorders in men. Such information is useful to help occupational health practitioners and policy makers conduct preventive programmes on shoulder disorders in this working population. Future longitudinal studies on work-related shoulder disorders are warranted.

The health impacts of semiconductor production: an epidemiologic review

BACKGROUND

Despite concerns over the harmful health effects of semiconductor production, epidemiological studies have shown mixed results.

OBJECTIVES

We aim to critically appraise epidemiologic studies to date, and to suggest future research and actions to protect workers in semiconductor industry.

METHODS

Epidemiologic studies were identified through electronic database searches, review of reference lists of relevant published works, and expert consultations, and were narratively reviewed.

RESULTS

Most evidence suggests reproductive risks from fabrication jobs, including spontaneous abortion (SAB), congenital malformation, and reduced fertility. Although chemicals have been suspected as causal agents, knowledge of the likely contribution(s) from specific exposures is still limited. Evidence of cancer risk seems to be equivocal. However, the available studies had serious limitations including healthy worker effects (HWEs), information bias, and insufficient power, all of which are associated with underestimation. Nevertheless, excess risks for non-Hodgkin's lymphoma (NHL), leukemia, brain tumor, and breast cancer were observed.

CONCLUSIONS

Monitoring and innovative research based on international collaboration with a focus on sentinel events are required.

Carpal tunnel syndrome and its relationship to occupation: a meta-analysis

OBJECTIVE

To examine the association between work place exposure and CTS by meta-analysis, including analyses with respect to exposure to hand force, repetition, vibration and wrist posture.

METHODS

All relevant peer-reviewed articles published between January 1980 and December 2009 were identified by a systematic search using the MEDLINE, CINAHL and PubMed databases. Papers were critiqued independently by two researchers and the relevant exposure information was extracted. Using the raw data of exposed and unexposed cases, a cumulative effect of specific exposure risks were calculated for hand force, repetition, a combination of force and repetition, vibration and wrist posture using the statistical program, Stata version 11 (StataCorp, College Station, TX, USA). Heterogeneity, meta-regression, publication bias and subgroup sensitivity analyses were performed.

RESULTS

Thirty-seven studies from English-language literature met the inclusion criteria. Using National Institute for Occupational Health and Safety criteria for case definition, a significant positive association between CTS and hand force, repetition, use of vibratory tools and wrist posture was observed with approximate doubling of risk for all exposures. Significant heterogeneity among studies was observed for most exposures and metaregression analyses identified CTS case definition, study design, country and risk of bias score to be the significant determinants. When a more conservative definition of CTS was employed to include nerve conduction abnormality with symptoms and/or signs, risk factors significantly associated with an increased risk of CTS among exposed workers were: vibration [odds ratio (OR) 5.40; 95% CI 3.14, 9.31], hand force (OR 4.23; 95% CI 1.53, 11.68) and repetition (OR 2.26; 95% CI 1.73, 2.94). There was a non-significant trend for the association between CTS and combined exposure to both force and repetition (OR 1.85; 95% CI 0.99, 3.45) and wrist posture (OR 4.73; 95% CI 0.42, 53.32).

CONCLUSION

Occupational exposure to excess vibration, increased hand force and repetition increase the risk of developing CTS. Workplace strategies to avoid overexposure to these risk factors should be implemented.

The burden and determinants of neck pain in workers: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Systematic review and best evidence synthesis.

OBJECTIVES

To describe the prevalence and incidence of neck pain and disability in workers; to identify risk factors for neck pain in workers; to propose an etiological diagram; and to make recommendations for future research.

SUMMARY OF BACKGROUND DATA

Previous reviews of the etiology of neck pain in workers relied on cross-sectional evidence. Recently published cohorts and randomized trials warrant a re-analysis of this body of research.

METHODS

We systematically searched Medline for literature published from 1980-2006. Retrieved articles were reviewed for relevance. Relevant articles were critically appraised. Articles judged to have adequate internal validity were included in our best evidence synthesis.

RESULTS

One hundred and nine papers on the burden and determinants of neck pain in workers were scientifically admissible. The annual prevalence of neck pain varied from 27.1% in Norway to 47.8% in Québec, Canada. Each year, between 11% and 14.1% of workers were limited in their activities because of neck pain. Risk factors associated with neck pain in workers include age, previous musculoskeletal pain, high quantitative job demands, low social support at work, job insecurity, low physical capacity, poor computer workstation design and work posture, sedentary work position, repetitive work and precision work. We found preliminary evidence that gender, occupation, headaches, emotional problems, smoking, poor job satisfaction, awkward work postures, poor physical work environment, and workers' ethnicity may be associated with neck pain. There is evidence that interventions aimed at modifying workstations and worker posture are not effective in reducing the incidence of neck pain in workers.

CONCLUSION

Neck disorders are a significant source of pain and activity limitations in workers. Most neck pain results from complex relationships between individual and workplace risk factors. No prevention strategies have been shown to reduce the incidence of neck pain in workers.

The burden and determinants of neck pain in workers: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Systematic review and best evidence synthesis.

OBJECTIVES

To describe the prevalence and incidence of neck pain and disability in workers; to identify risk factors for neck pain in workers; to propose an etiological diagram; and to make recommendations for future research.

SUMMARY OF BACKGROUND DATA

Previous reviews of the etiology of neck pain in workers relied on cross-sectional evidence. Recently published cohorts and randomized trials warrant a re-analysis of this body of research.

METHODS

We systematically searched Medline for literature published from 1980-2006. Retrieved articles were reviewed for relevance. Relevant articles were critically appraised. Articles judged to have adequate internal validity were included in our best evidence synthesis.

RESULTS

One hundred and nine papers on the burden and determinants of neck pain in workers were scientifically admissible. The annual prevalence of neck pain varied from 27.1% in Norway to 47.8% in Québec, Canada. Each year, between 11% and 14.1% of workers were limited in their activities because of neck pain. Risk factors associated with neck pain in workers include age, previous musculoskeletal pain, high quantitative job demands, low social support at work, job insecurity, low physical capacity, poor computer workstation design and work posture, sedentary work position, repetitive work and precision work. We found preliminary evidence that gender, occupation, headaches, emotional problems, smoking, poor job satisfaction, awkward work postures, poor physical work environment, and workers' ethnicity may be associated with neck pain. There is evidence that interventions aimed at modifying workstations and worker posture are not effective in reducing the incidence of neck pain in workers.

CONCLUSION

Neck disorders are a significant source of pain and activity limitations in workers. Most neck pain results from complex relationships between individual and workplace risk factors. No prevention strategies have been shown to reduce the incidence of neck pain in workers.

Are psychosocial factors, risk factors for symptoms and signs of the shoulder, elbow, or hand/wrist?: A review of the epidemiological literature

BACKGROUND

In 1993, an extensive review on the role of psychosocial factors in the development of musculoskeletal problems was published by Bongers et al (1993). Since then, additional reviews on this topic have been published; however, none of these focussed on upper limb problems.

METHODS

In this systematic review, the methodological quality of all studies was assessed and levels of evidence were apriori defined.

RESULTS

The large majority of the studies reported an association between at least one work-related psychosocial factor and adverse upper extremity symptoms or signs. High-perceived job stress was consistently associated with all upper extremity problems (UEP) in high and lower quality studies. Although not often studied, non-work-related stress was also consistently associated with UEP. In addition, there was some evidence for a relationship between high job demands and UEP, although the results did not meet the pre-set criterion for consistency.

CONCLUSIONS

High job stress and non-work-related stress reactions are consistently associated with UEP. In addition, high job demands is also in most studies associated with these disorders. Firm conclusions on the role of these factors in the etiology of UEP are not possible due to the cross-sectional nature of most studies.

The effects of container design and stair climbing on maximal acceptable lift weight, wrist posture, psychophysical, and physiological responses in wafer-handling tasks

Despite the high level of automation in semiconductor manufacturing processes, many manual operations are still involved in the workplace. Due to inadequate human-machine interface design, stairs are frequently used to help operators perform wafer-handling tasks. This study was designed to evaluate the effects of climbing stairs and carrying wafer containers (pods) on psychophysical responses (maximal acceptable weight of lift--MAWL, and ratings of perceived exertion--RPE), physiological responses (oxygen consumption--VO2, and heart rate--HR), and wrist posture (ulnar and radial deviations). Each of 12 subjects (six males and six females) performed six sessions (3 climbing stairs x 2 pods types). The results indicate that climbing stairs had a significant influence on MAWL and VO2 (p<0.01). The type of pod effect on wrist posture was significant (p<0.01). Gender effect differences on MAWL, VO2 and wrist posture were also significant (p<0.05). Job design implications are discussed.

Psychosocial risk factors for neck pain: a systematic review

BACKGROUND

Neck pain, which is assumed to be a multifactorial disease, is a major problem in modern society.

METHODS

To identify the most important psychosocial risk factors for neck pain, a systematic review of the literature was carried out. The methodological quality of all studies in the review was assessed. Four levels of evidence were defined to assess the strength of evidence for potential risk factors for neck pain (strong, moderate, some or inconclusive evidence).

RESULTS

Some evidence was found for a positive relationship between neck pain and high quantitative job demands, low social (coworker) support, low job control, high and low skill discretion and low job satisfaction. Inconclusive evidence was found for high job strain, low supervisor support, conflicts at work, low job security, and limited rest break opportunities.

CONCLUSIONS

The procedure of the assessment of the methodological quality and the rating system applied to distinguish between high- and low-score studies, had a considerable influence on the level of evidence, indicating that changes in this procedure may have a major impact on the overall conclusions of this review.

[Occupational activity and prevalence of osteomuscular pain among dentists in Belo Horizonte, Minas Gerais State, Brazil: a contribution to the debate on work-related musculoskeletal disorders]

The objective was to determine the prevalence of upper-limb and back pain among dentists (n = 358) and factors associated with these symptoms. Dentists were interviewed using a self-administered questionnaire containing data on sociodemographic, occupational, lifestyle, and psychosocial factors and presence, site, and characteristics of pain. Participation rate was 92.3%. 58% reported upper limb pain, with 22, 21, 20, and 17% for the arm, back, neck, and shoulder, respectively. 26% reported daily frequency and 40% classified pain as moderate or severe. In the multivariate analysis (multiple logistic regression), the factors associated with pain were: neck: anxiety/depression (OR = 2.3; CI95%: 1.2-4.5), compressor in the office (OR = 2.1; CI95%: 1.2-3.7), job satisfaction (OR = 0.3; CI95%: 0.1-0.9), and use of indirect vision (OR = 0.5; CI95%: 0.3-0.9); shoulder: income > 20 minimum wage (OR = 2.9; CI95%: 1.2-6.7), greater productivity (OR = 3.3; CI95%: 1.3-8.4), height > or = 160cm (OR = 0.3; CI95%: 0.2-0.7), and age 30-49 years (OR = 0.3; CI95%: 0.1-0.8); back: anxiety/depression (OR = 2.3; CI95%: 1.2-4.5), manual activity (OR = 0.4; CI95%: 0.2-0.9), and being married (OR = 0.5; CI95%: 0.3-0.9); arms: manual activity (OR = 1.8; CI95%: 1.0-3.2).

The prevalence of musculoskeletal complaints among women in Tijuana, Mexico: sociodemographic and occupational risk factors

The authors interviewed an age- and occupation-stratified sample of 466 women, aged 18-40, from 12 Tijuana neighborhoods, about sociodemographic characteristics, work and reproductive history, and musculoskeletal complaints. A total of 29.8% reported experiencing aches or pain in the low back, 38.3% in the upper back, 26.4% in the neck/shoulders, 18.2% in the hand/wrist, and 28.3% in the legs in the preceding year. Both sociodemographic and occupational factors were associated with these complaints. Very low educational attainment, having substandard housing, being the head of household, and being a migrant were each associated with an increased prevalence of one or more musculoskeletal complaints. In general, working outside the home increased the risk of musculoskeletal complaints. Compared with women who had not worked in the preceding 30-month period, those working in the maquiladora had 40-90% higher risks of upper back, neck/shoulder, and hand/wrist pain. Compared with women working outside the maquiladora, maquiladora women workers had 20% higher risks of low back, upper back, and neck/shoulder complaints. More detailed studies of the incidences of musculoskeletal disorders and of specific etiologic risk factors within the maquiladora industry are warranted. Future studies should concurrently evaluate sociodemographic risk factors.

Meta-analysis of published studies of work-related carpal tunnel syndrome

The published information about work-related carpal tunnel syndrome (CTS) was surveyed to identify risk estimates and possible biases influencing the risk estimates. Seventeen studies from the English-language literature were identified and study characteristics were coded for univariate and regression analysis. Country of publication, study population, force, and repetitive motion were significant predictors or risk, with R(2) = 0.57, adjusted R(2) = 0.43, Cp = 5.79, and AIC = 19.6 using the best-subset method of variable selection. Using the forward-variable selection method, country, study population, study type, and repetitive motion were significant predictors, with R(2) = 0.57, Cp = 6.24, p = 0.033. Excess risks of work-related CTS were consistent in the studies reviewed. Studies published in the United States reported higher risk estimates than did those published elsewhere. Some industrial populations were found to have higher risk estimates than others. Cross-sectional designs were the most common epidemiologic approach, but are not without methodologic concerns.

Association of spontaneous abortion and other reproductive effects with work in the semiconductor industry

This study tested the hypothesis that fabrication room (fab) work in the silicon-based semiconductor industry is associated with an increased risk of spontaneous abortion (SAB). The study was conducted nationwide at 14 companies representing a spectrum of large to small manufacturers. A small increase in risk of SAB was observed among fab workers compared with nonfabrication room (nonfab) workers in two cohorts, historical (adjusted RR = 1.43, 95% confidence interval [CI] 0.95-2.09) and prospective (adjusted RR = 1.25, 95% CI = 0.63-1.76). Analysis of specific fab exposures in the historical cohort showed a consistent, dose-response association of SAB with photoresist and developer solvents, whose major component was ethylene-based glycol ethers. The consistency of our findings and the toxicological data for these agents suggest that this is a causal association. Independent associations of SAB with self-reported stress and with etching fluorides were observed and require further research. No significant decrease in fertility was observed among men or women working in fabs, but reduced fecundability was suggested for some women fab workers.

A cross-sectional survey of respiratory and general health outcomes among semiconductor industry workers

As part of the Semiconductor Health Study, we performed a cross-sectional survey to assess prevalence of specific nonreproductive health outcomes and their association with occupational exposures. A total of 3,175 persons from eight manufacturing sites across the U.S. completed a health and work questionnaire (78% participation rate). After adjusting for confounders, responses from fabrication room (fab) workers indicated a greater risk than those of nonfab workers for upper respiratory symptoms (relative risk [RR] = 1.08; 95% confidence interval [CI] = 1.03-1.13); a dose-response effect with hours per day spent in fabs was observed. Fab workers also had greater prevalence for persistent wheezing (RR = 1.82; 95% CI = 1.15-2.87), dermatitis within the past year (RR = 1.19; 95% CI = 1.04-1.35), and alopecia (RR = 1.73; 95% CI = 1.16-2.54). Female sex, a somatization index score, and smoking were important nonoccupational covariates. Increased respiratory symptoms may result from occupational exposures in fabs; further research is needed to identify causal agents and develop prevention strategies.