Assessment of Diffusing Capacity of Lung for Carbon Monoxide (DLCO)

Background: Diagnosis of lung diseases associated with silica exposure typically relies on a history of occupational silica dust exposure and chest X-ray. Diffusing capacity of the lung for carbon monoxide (DLCO) is a pulmonary function test that measures the lungs' ability to transfer gas from inspired air to the bloodstream. Aims: To analyses the role of DLCO in the early detection of lung function impairment in asymptomatic or symptomatic workers exposed to silica dust for 5 years or more. Settings and Design: An observational study conducted in a tertiary care center of Rajasthan. Methods and Materials: A total of 50 silica-exposed workers without a history of Tuberculosis and other pneumoconiosis were enrolled based on inclusion criteria. Each participant underwent a detailed clinical history, physical examination, chest X-ray, hemoglobin, spirometry, and DLCO. Statistical Analysis Used: Pearson and Spearman tests were used for correlation. Categorical data were compared by the Chi-square test, and medians were compared with the Mann-Whitney U test. A Results: The study population had a median age of 44 years, and 90% were male. The median duration of silica exposure was 15.5 years, and the majority were stone-cutters. DLCO and spirometry detected abnormalities in 72% and 52% of the study population, respectively. Notably, more than half (66.6%) of the participants with normal spirometry had impaired DLCO, recommending the addition of DLCO in the surveillance of silica-exposed workers. A significant correlation was observed between the duration of silica exposure and the severity of impairment. Conclusions: DLCO can detect lung function impairment in asymptomatic or mildly symptomatic silica-exposed workers.