ABSTRACT
Background Bus drivers are a high-risk group for work-related musculoskeletal disorders (WMSDs). There are a large number of bus drivers in mega-cities. High volumes of passenger traffic and complexity of road conditions may elevate their risk of WMSDs, but there are few studies related to this group. Objective To investigate the prevalence of WMSDs among bus drivers in a mega-city and to analyze potential influencing factors. Methods Based on cross-sectional study design and self-administered questionnaire, the prevalence of WMSDs in past 12 months were estimated by stratified cluster sampling among bus drivers in a mega-city. Pearson χ2 and logistic regression models were used to analyze the influencing factors for the body regions with a high prevalence. Results The overall prevalence of WMSDs in past 12 months among bus drivers in a mega-city was 49.5% (551/1113). The prevalence of WMSDs by body regions ranged from 4.0% to 38.5%, and led by neck pain (38.5%), lower back pain (25.5%), and shoulder pain (20.8%). The results of logistic regression showed that the risk factors for neck pain were age (>50 years), smoking, tiredness after work (moderate, severe), long sitting (frequently), awkward postures (sometimes, often, frequently), overtime(occasionally, often), workplace temperature (uncomfortable), and noise (severe) (OR=2.014、1.577、2.793、3.025、2.708、2.032、3.406、2.746、1.442、2.998、1.456、3.506；P<0.05); the lower back pain risk factors were current work experience (6-10 years, 11-15 years, and 16-20 years), smoking, tiredness after work (moderate, severe), and awkward postures(sometimes, often, frequently)(OR=1.777、2.130、2.400、1.503、2.951、3.364、1.836、4.569、2.786，P<0.05); and the shoulder pain risk factors were age (46-50 years, and >50 years), smoking, tiredness after work (moderate, severe), vehicle type (hybrid power, diesel oil), awkward postures (often, frequently), overtime (often), and workplace temperature (uncomfortable) (OR=1.737、2.357、1.553、2.259、2.489、1.659、3.295、2.777、3.320、2.266、1.426，P<0.05). Identified protective factors for neck and lower back pain were off-duty physical activity (1-2 times per week, and ≥3 times per week) (OR=0.553、0.470、0.586、0.485，P<0.05). Conclusion Nearly half of the bus drivers in the mega-city report symptoms of WMSDs, mainly in the neck, lower back, and shoulders. The prevalence is related to individual and occupational factors, and prevention and intervention measures should be actively taken.
ABSTRACT
{L-End}Objective To explore the suitable methods for individual occupational stress examination and evaluation for workers in China based on the electronics industry. {L-End}Methods A total of 1 164 workers from four electronics enterprises in Beijing City were selected as the research subjects using a convenient sampling method. The Occupational Stress Measurement Scale, which was developed based on the Japanese Brief Job Stress Questionnaire, was used to assess the occupational stress of the research subjects, and test the reliability and validity of the scale. Percentile norms and T-score norms were established, and the T-scores of the three dimensions of stress reaction (psychological reaction and physical symptoms), stress factors, and social support were divided into five stages using the normal distribution method with x¯±0.5 s and x¯±1.5 s, which was used to explore a proposed standard for assessing individual stress levels. {L-End}Results The revised scale consisted of 57 items, which could explain 64.0% of the total variation of occupational stress based on the result of item analysis and exploratory factor analysis. The results of confirmatory factor analysis showed that the model fitted well, with root mean square error of approximation of 0.052, standardized root mean square residual of 0.070, comparative fit index of 0.960, and Tucker-Lewis index of 0.958. The Cronbach's α coefficient of the scale was 0.951, and the Spearman-Brown coefficient was 0.837. Cronbach's α coefficients of the three dimensions ranged from 0.794 to 0.952, and the Spearman-Brown coefficients ranged from 0.737 to 0.850. The scores of the three dimensions of stress reaction, stress factors, and social support were (49.1±13.0), (44.9±7.7), and (18.1±3.6), respectively. Workers in the electronics industry met one of the following items were identified as the high level of occupational stress individuals: i) a score of stress reaction dimension ≥72.0 points; ii) a sum of stress factor and social support dimension scores ≥81.0 points, and a stress reaction dimension score ≥58.0 points. {L-End}Conclusion The Occupational Stress Measurement Scale and the criteria for determining high level of occupational stress can be used to assess the individual occupational stress levels of workers in the electronics industry in China. This method can provide a theoretical basis for the formulation of occupational stress examination and assessment for Chinese workers.