Abstract: Objective To understand the incidence of work-related musculoskeletal disorders(WRMSDs) among open-pit coal miners in Xinjiang,identify the incidence pattern of WRMSDs in this group through latent class analysis(LCA),and explore the relationship between related influencing factors and the incidence pattern of WRMSDs. Methods From January to October 2023,a cluster sampling method was used to conduct a questionnaire survey of 3 590 employees in 5 large open-pit coal mining enterprises in Xinjiang,and the data were analyzed. Results The annual symptom incidence of WRMSDs among open-pit coal miners in Xinjiang was 1 469,with an incidence rate of 40.9%. The top three body parts with the highest incidence rates were the waist (940,26.2%),the neck(916,25.5%) and the shoulder(782,21.8%),the hip and buttocks(249,6.9%) with the lowest incidence rate.The optimal model for the incidence patterns of WRMSDs among open-pit coal miners in Xinjiang was a five-category model,which included the following groups respectively：the shoulder-neck-waist pain group(418,11.64%),only waist pain group (164,4.57%),the pain in all body parts group(157,4.37%),the upper body pain group(284,7.91%),and the mild pain group(2 567,71.5%). After occupational factors were incorporated into the model,it was found that the conditional probability of "having sufficient rest time" was relatively low in all categories(all ρ<0.500),and the situation of "working in a cold environment" was commonly seen in all categories(ρ>0.700). The conditional probabilities of the 9 occupational risk factors were relatively high in both the pain in all body parts group and the upper body pain group(all ρ>0.500).After grouping by cumulative fatigue,except that the non-cumulative fatigue group was divided into four categories,the mild,moderate and severe cumulative fatigue groups were each divided into three categories. The upper body pain group existed in all four groups,and its category probabilities were 4.28%,30.21%,37.10% and 36.74%,respectively.After incorporating sleep quality as a covariate into the analysis,except that there was no significant difference between the "pain in all body parts group" and the "upper body pain group" in the mild cumulative fatigue group,all other classification differences were statistically significant(all P<0.01). Conclusion The incidence rate of WRMSDs among open-pit coal miners is relatively high,and it often occurs in the waist,neck and shoulder areas. Exposure to different occupational factors can lead workers to fall into different pain classifications. As the level of cumulative fatigue increases,the probability of open-pit coal miners experiencing upper body pain becomes greater. Sleep quality is related to the classification of the incidence patterns of WRMSDs,and good sleep quality may reduce the risk of workers having the pain pattern in multiple body parts.

Key words: Open-pit coal miners, Work-related musculoskeletal disorders, Latent class analysis, Influencing factors, Disease patterns