Musculoskeletal Symptom Burden Across Occupations in Korea: Linking Korean Working Conditions Survey Data with a Body-Part–Specific Exposure Assessment

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.