by InHo Lee, SangHee Hong, EunChul Jang, JuneHee Lee, JeongBeom Lee Background Confined space work exposes workers to complex risks, including oxygen deficiency, hazardous gases, and physical strain, requiring structured criteria for fitness-for-duty screening. This study aimed to develop a Confined-Space Suitability Index (CSSI) based on routinely available health examination and functional test data.
Methods A total of 111 workers were analyzed. Risk factors were classified into anthropometric and metabolic factors, functional and physiological factors, and lifestyle factors.
Low cardiorespiratory fitness was defined using age- and sex-specific VO₂max reference thresholds from Korea Occupational Safety and Health Agency (KOSHA) H-43–2021 and Canadian Public Health Association reference values. Risk-factor weights were derived using LASSO regression, and internal validation was performed using leave-one-out cross-validation and bootstrap stability analysis.
Results According to the revised CSSI criteria, 86 workers were classified as suitable, 19 as caution, and 6 as unsuitable. The independent specialist assessment classified 7 workers as unsuitable.
PLOS ONE (Medicine) published a clinical update in Research Highlights on 02 Jun 2026.
The item focuses on Development of a Confined-Space Suitability Index (CSSI) using Least Absolute Shrinkage and Selection Operator (LASSO) regression: a pilot study for structured fitness-for-duty screening.
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