Background and objectives: Musculoskeletal disorders (MSDs) account for more than 60% of compensated occupational diseases in Korea. Despite this burden, benchmarks of standardized ergonomic exposure and evidence on the combined effects of risk factors remain limited. This study aimed to construct a body part-specific ergonomic job exposure matrix (JEM) and evaluate the independent and interactive effects of ergonomic, demographic, and work-related factors. Materials and Methods: We analyzed the data of 210,500 workers from the 2nd–6th Korean Working Conditions Survey (2009–2020). A JEM for arms/neck, back, and legs was developed and validated (κ ≥ 0.79). Logistic regression models estimated adjusted odds ratios (aORs), and additive interactions were assessed using relative excess risk due to interaction (RERI), attributable proportion (AP), and the synergy index (SI). Results: High ergonomic exposure was strongly associated with MSDs across all body regions (aORs 2.3–2.5). Age > 45 years, long working hours (>52 h), and high job strain also increased risks (aORs 1.4–2.3). On the additive scale, ergonomic risk combined with older age showed consistent synergy (RERI up to 1.5; SI >1.5), whereas combinations with long working hours or job strain showed attenuation (RERI < 0; SI < 1). Women reported higher crude prevalence but lower adjusted odds (aOR ≈ 0.9). Conclusions: This nationally representative study demonstrates that ergonomic risk, age, long working hours, and job strain are major determinants of MSDs. The validated Korean JEM provides a standardized tool for surveillance and compensation. However, the cross-sectional design limits causal inference. Future longitudinal research with objective exposure measures is needed to strengthen causal inference and guide tailored prevention.

Background and objectives: Musculoskeletal disorders (MSDs) are the most common work-related diseases in Korea, yet nation-wide estimations of their occupational burden remain scarce. This study aimed to (1) assess the prevalence and distribution of MSD symptoms by body part; (2) construct a body-part–specific job exposure matrix (JEM) for ergonomic risk factors using representative national data; (3) validate the JEM through expert consensus; and (4) examine dose–response relationships be-tween exposure intensity and MSD symptoms. Materials and Methods: We analyzed data from 215,000 Korean workers across five waves (2006–2020) of the Korean Working Conditions Survey (KWCS). A JEM was created based on self-reported ergo-nomic exposures by occupational category. Expert review and agreement statistics were used to validate exposure estimates. Logistic regression was applied to evaluate associations between exposure levels and MSD symptoms. Results: Symptoms were re-ported in the upper extremities and neck (35.3%), back (20.3%), and lower extremities (24.6%), with over 40% of respondents experiencing symptoms in multiple body parts. The JEM showed strong agreement with expert ratings (κ ≥ 0.80 for upper body and back), and exposure intensity was positively associated with symptom prevalence, particularly in the upper body and back. Occupations such as crop growers and construction workers had high levels of both exposure and symptom burden. Conclusions: This study developed and validated the first body-part–specific ergonomic JEM for Korean workers using nationally representative data. Findings support data-driven prioritization of high-risk occupations and provide a foundation for future surveillance and prevention of work-related MSDs in Korea.

Background: This study attempted to construct musculoskeletal JEM using KWCS data and use it to evaluate the burden of these disorders in Korean workers. Methods: This study was conducted using data from the second to the sixth KWCS, and a total of 210,500 people were included. The jobs of the subjects were reclassified based on the unit groups of the 7th Korean Standard Classification of Occupation (KSCO). The intensity of exposure to work-related risk factors for musculoskeletal disorders was classified into ‘high’, ‘moderate’, and ‘low’ for the body segments involving the ‘upper extremities and neck’, ‘lower back’, and ‘lower extremities’. Results: The time of exposure was longest in the standing posture and repetitive hand and arm movements. An analysis of the intensity of exposure by body segments revealed that the highest intensity of exposure was to the upper extremities. For the upper extremities and neck, and the lower back, there was a exposure-response relationship in the association between intensity of exposure and musculoskeletal symptoms. However, for the lower extremities, there was a exposure-response relationship only at high exposure. Conclusion: In this study, a JEM for work-related risk factors for musculoskeletal disorders was constructed for the first time in Korea. The intensity of exposure to musculoskeletal risk factors was estimated for each occupation. The JEM constructed in this study is expected to have high applicability for assessing the risk of musculoskeletal disorders for each job with respect to the upper extremities and neck, and lower back.

Background and objectives: Musculoskeletal disorders (MSDs) account for more than 60% of compensated occupational diseases in Korea. Despite this burden, benchmarks of standardized ergonomic exposure and evidence on the combined effects of risk factors remain limited. This study aimed to construct a body part–specific ergonomic job-exposure matrix (JEM) and evaluate the independent and interactive effects of ergo-nomic, demographic, and work-related factors. Materials and Methods: We analyzed the data of 210,500 workers from the 2nd–6th Korean Working Conditions Survey (2009–2020). A JEM for arms/neck, back, and legs was developed and validated (κ≥0.79). Logistic regression models estimated adjusted odds ratios (aORs), and additive interactions were assessed using relative excess risk due to interaction (RERI), attributable proportion (AP), and the synergy index (SI). Results: High ergonomic exposure was strongly associated with MSDs across all body regions (aORs 2.3–2.5). Age >45 years, long working hours (>52 h), and high job strain also increased risks (aORs 1.4–2.3). On the additive scale, ergo-nomic risk combined with older age showed consistent synergy (RERI up to 1.5; SI >1.5), whereas combinations with long working hours or job strain showed attenuation (RERI < 0; SI < 1). Women reported higher crude prevalence but lower adjusted odds (aOR ≈0.9). Conclusions: This nationally representative study demonstrates that ergonomic risk, age, long working hours, and job strain are major determinants of MSDs. The validated Korean JEM provides a standardized tool for surveillance and compensation. However, the cross-sectional design limits causal inference. Future longitudinal research with objective exposure measures is needed to strengthen causal inference and guide tailored preven-tion.

Background: Musculoskeletal disorders (MSDs) are a major occupational health issue in Korea; however, a standardized job-exposure matrix (JEM) has not been established. This study aimed to develop an MSD-specific JEM using data from the Korean Working Conditions Survey (KWCS) to evaluate the exposure time proportion by job category and body segment.Methods: Data from the 2nd to 6th KWCS (2006–2020), covering 210,500 workers, were analyzed. The jobs of the subjects were reclassified based on the unit groups of the 7th Korean Standard Classification of Occupations. Exposure time proportion for key MSD risk factors—repetitive movements, awkward postures, heavy lifting, and prolonged standing—was categorized as high, moderate, or low based on self-reported responses. Validity was assessed through expert review and statistical analysis, including Cohen’s kappa coefficients and logistic regression.Results: Duration-based exposure to musculoskeletal (MS) risk factors was estimated for each occupation. The JEM classified exposure time proportion for three body regions: upper extremity and neck, lower back, and lower extremity. Expert review showed high agreement for the upper extremity and neck and for the lower back (kappa > 0.8), whereas agreement was lower for the lower extremity. Logistic regression analysis indicated an exposure–response relationship between JEM-derived exposure time proportion and MS symptoms for the upper extremity and neck and the lower back.Conclusions: This study developed Korea’s first MS-specific JEM, providing a standardized framework for occupational MSD risk assessment. The JEM demonstrated strong validity for most body regions and can be a valuable tool for research, workplace risk evaluation, and policy development. Further refinements incorporating detailed job classifications and ergonomic factors are recommended to enhance its applicability.