ABSTRACT
Background The prevalence rate of work-related musculoskeletal disorders (WMSDs) among manufacturing workers is relatively high and has been widely concerned. However, research on the prevalence and risk factors of multi-site WMSDs is still insufficient. Objective To explore the prevalence and risk factors of multi-site WMSDs of assembly workers in four manufacturing enterprises. Methods The "Chinese Musculoskeletal Questionnaire" was used to conduct a cross-sectional survey among 1401 assembly workers selected by convenient sampling in four manufacturing enterprises, and their demographic characteristics, the prevalence of WMSDs in various body parts, and the information about biomechanical factors, work organizations, work environment, and psychosocial factor exposure were collected. The prevalence of WMSDs and multi-site WMSDs were estimated, Pearson χ2 test was used for univariate analysis of multi-site WMSDs risk factors, and logistic regression was used for multi-factor analysis. Results The total prevalence rate of WMSDs was 54.9% (769/1 401). The top three affected sites were neck (41.4%), shoulders (30.7%), and wrist/hand (25.1%). The prevalence rate of multi-site WMSDs was 41.9% (587/1 401). The prevalence rates of multi-site WMSDs in railway vehicle assembly and riveting workers were higher than those in electronic parts processing and glass manufacturing workers (P<0.001). The results of logistic regression analysis showed that individual factors such as female (OR=2.09, 95%CI: 1.48−2.97) and drinking (OR=1.52, 95%CI: 1.05−2.18), biomechanics factors such as keeping head down for a long time (OR=1.37, 95%CI: 1.22–1.53), keeping bending frequently (OR=1.18, 95%CI: 1.03–1.34), and keeping arms up for a long time (OR=1.25, 95%CI: 1.10–1.41), work organizational factors such as electronic parts processing, railway vehicle assembly, and riveting (OR values were 3.23, 5.70, and 13.83, respectively), environmental factors such as temperature a little cold (OR=4.84, 95%CI: 1.90–12.37), noise seriously affecting work (OR=2.25, 95%CI: 1.23–4.11), and psychosocial factors such as high job demands (OR=1.47, 95%CI: 1.04–2.08), fatigue after work (OR=1.92−2.61) were risk factors of multi-site WMSDs. Conclusion The prevalence rate of multi-site WMSDs in assembly workers is high, and the main influencing factors include individual factors, awkward work postures, environmental factors, and psychosocial factors.
ABSTRACT
Most studies have examined the association of ergonomic risk factors and musculoskeletal discomfort in developed countries. Meanwhile the data are still lacking in developing countries such as Malaysia. The aim of this study was to determine the relation between risk factors and musculoskeletal discomfort among manual material handling workers in Malaysian automotive industries. A total of211 manual material handling workers from automotive industries completed a set of questionnaire on the individual, physical and environmental factors and the prevalence of musculoskeletal discomfort. The Chi-Square test and logistics regression analysis were used to determine the relationship of the risk factors and musculoskeletal. The findings highlighted that job tenure was significantly correlated with musculoskeletal discomfort among the workers (OR=2.33-5.56). The most significant physical risk factor that was associated with musculoskeletal discomfort was bending the trunk forward slightly, hands above knee level, which was significantly related to lower back discomfort (OR=5.13, 95%CI=1.56-16.8), thigh discomfort (OR=5.1, 95%CI=1.01-25.53) and wrist discomfort (OR=3.65, 95%CI=1.06-12.53). Twisting of the trunk (over 45o) and bending sideways were significantly associated to lower back discomfort (OR=4.04, 95%CI=1.44-14.44), and thigh discomfort (OR=4.3, 95%CI=1.29-8.50). The findings also highlighted that environmental factors was associated with musculoskeletal discomfort (p < 0.05. Musculoskeletal discomfort can be reduced by lowering work-related risk factors among automotive manual material handling workers, particularly by focusing on significant factors, including job tenure, bending or twisting postures and environmental factors.