Prevalence and risk factors of musculoskeletal symptoms among municipal solid waste workers in Phayao Province, Northern Thailand

Abstract

Background: Solid waste management needs to be performed worldwide. In developing countries, municipal solid waste is collected manually, requiring heavy physical labor outdoors, which may contribute to the development of work-related musculoskeletal disorders (MSDs). Purpose: To determine the prevalence and risk factors of musculoskeletal symptoms among municipal solid waste workers in local administrative organizations in Phayao Province, Northern Thailand. Methods: A cross-sectional analytic study using sociodemographic, work profile and environment workplace exposure data was conducted. The Standard Nordic Questionnaires among municipal solid waste workers (MSWWs) were used to interview 135 employees who participated in the study. Results: The highest prevalence of musculoskeletal symptoms among MSWWs was shoulder pain (55.56%), followed by low back pain (42.96%), wrist/hand pain (42.22%) and ankle pain (30.37%). There was one risk factor that was significantly associated with musculoskeletal symptoms: a frequency of lifting of ≥150 times/day [adjusted odds ratio (aOR) 4.46; 95% confidence interval (CI), 1.28–15.48]. Additionally, regarding body parts, a frequency of lifting of ≥150 times /day was shown to be a risk factor for wrist/hand pain [aOR 3.06; 95% CI, 1.11–8.44] and knee pain [aOR 4.00; 95% CI, 1.05–15.20]. Lifting heavy objects above the knees was associated with a risk of shoulder pain [aOR 3.80; 95% CI, 1.56–9.26], and workers who lifted objects continuously were at risk of knee pain [aOR 4.97; 95%CI, 1.02–24.31]. Conclusion: These findings demonstrate that the frequency of lifting, lifting continuously and lifting objects above the knees are risk factors for musculoskeletal symptoms, and it is recommended that MSWWs’ posture and workplace environment are monitored.