Cross-sectional survey on musculoskeletal disorders and related factors of wolfberry harvesters in Ningxia

Background Wolfberry industry is one of the leading industries in Ningxia. While promoting farmers' income, awkward working postures and high-intensity repetitive picking task adversely affect the health of pickers.

Objective This study investigates the prevalence of work-related musculoskeletal disorders (WMSDs) in wolfberry harvesters in Ningxia, and analyzes its potential influencing factors.

Methods From August to October 2018, a cluster random sampling method was adopted to select 500 wolfberry harvesters as study subjects from 1-2 villages from each of the 6 townships of Zhongning and Tongxin counties in Ningxia where wolfberry cultivation was most concentrated. The general demographic variables, living habits, working characteristics, and WMSDs occurrence of the wolfberry harvesters were collected through the US Agricultural Health Study Questionnaire and the Standardized Nordic Musculoskeletal Disorders Questionnaire. Logistic regression models were adopted to identify the potential influencing factors of WMSDs.

Results A total of 482 valid questionnaires were returned (96.4%). The prevalence of WMSDs among the wolfberry harvesters was 92.5% (446/482). Among them, 170 workers had a confirmed hospital diagnosis of WMSDs, accounting for 35.3% (170/482) of total respondents, and 276 workers were not diagnosed but self-reported having symptoms of general or local musculoskeletal pain and discomfort, accounting for 88.5% (276/312) of the workers without a WMSDs diagnosis. The results of multiple analysis showed that the wolfberry harvesters with longer local residence time (OR=1.994, 95% CI: 1.110-3.581) and smokers (OR=3.990, 95% CI: 1.004-15.868) had a higher WMSDs prevalence rate, while those who well knew about the types of pesticides (OR=0.252, 95% CI: 0.104-0.611) and who had higher levels of education (OR=0.626, 95%CI: 0.405-0.966) had a lower WMSDs prevalence rate.

Conclusion The findings show a relatively high prevalence of WMSDs in wolfberry harvesters, and education level, length of local residence, smoking, and knowledge of pesticide types are the potential influencing factors of WMSDs.