Objective To investigate the prevalence and influencing factors of work-related musculoskeletal disorders (WMSDs) in neck, shoulders and lower back among power grid workers. Methods A total of 371 workers from a power grid enterprise in Guangdong Province were selected as the research subjects using the convenience sampling method. A cross-sectional survey of WMSDs in the neck, shoulders and waist of the workers was conducted using the modified Musculoskeletal Disorders Questionnaire. Results The overall prevalence of WMSDs among the power grid workers was 62.8%, with prevalence of 37.2%, 33.7% and 32.1% for WMSDs in neck, shoulders and lower back, respectively. Binary logistic regression analysis showed that power grid workers who did not maintain a good sitting posture or were unable to maintain good sitting posture over prolonged periods had a higher risk of neck WMSDs than those who maintained a good sitting posture (both P<0.01). A higher frequency of head-down posture during work was associated with an increased risk of neck WMSDs (both P<0.05). Female workers had a higher risk of shoulder WMSDs than male workers (P<0.05). A higher frequency of early awakening with inability to fall back asleep, as well as a higher frequency of head-down posture during work, were both associated with an increased risk of shoulder WMSDs (all P<0.05). Workers with a sedentary habit had a higher risk of shoulder WMSDs than those without (P<0.01). Workers with insufficient rest time had a higher risk of shoulder WMSDs than those with sufficient rest time (P<0.01). Both maintenance workers and managers had a higher risk of lower back WMSDs than workers in other occupational categories (all P<0.05). Workers who experienced nocturnal awakening with difficulty falling back asleep at frequency of several times per year, ≥1 time /month, ≥1 time /week, had higher risk of lower back WMSDs than those who never experienced such problem (all P<0.05). Workers with a sedentary habit and those uncertain about having a sedentary habit both had a higher risk of lower back WMSDs than those without (both P<0.05). Greater forward neck flexion during work was associated with an increased risk of lower back WMSDs (both P<0.05). Workers who occasionally tilted their necks to the side while working had a higher risk of lower back WMSDs than those who did not (P<0.05). Conclusion WMSDs are highly prevalent among power grid workers, particularly affecting the neck, shoulder, and waist. Influencing factors include individual characteristics, behavioral habits, work organization, work posture, and workload. Maintaining proper posture and adequate rest may reduce the risk of WMSDs.

Objective To explore the application value of distortion product otoacoustic emission (DPOAE) and speech in noise(SIN) testing in occupational health surveillance of noise-exposed workers. Methods A total of 220 noise-exposed workers was selected as the study subjects using the convenient sampling method. The study subjects participated questionnaire survey, personal noise exposure assessment, acoustic immittance testing, pure tone audiometry (PTA), DPOAE and SIN testing. According to PTA results, workers were enrolled into a high-frequency hearing loss (HFHL) group and a non-HFHL group. Results The detection rate of HFHL among the study subjects was 41.4%, and the detection rate of speech-frequency hearing loss was 15.9%. Workers′ bilateral DPOAE response amplitudes and signal-to-noise ratios at frequencies of 2.0-8.0 kHz in the HFHL group were lower than those in the non-HFHL group (all P<0.05). The DPOAE amplitudes at frequencies of 1.0-8.0 kHz in both ears of the study subjects were negatively correlated with the PTA threshold (all P<0.01), and were negatively correlated with age (all P<0.01). The signal-to-noise ratio loss score was higher among worker in the HFHL group than in the non-HFHL group (P<0.01) and was positively correlated with PTA thresholds (P<0.05). Conclusion DPOAE and SIN testing can detect early cochlear outer hair cell impairment and reduction of noise-related speech recognition ability in noise-exposed workers and may serve as an effective supplementary tool to routine PTA in occupational hearing surveillance.