Assessment of Diffusing Capacity of Lung for Carbon Monoxide (DLCO) in Silica-Exposed Workers

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.

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.

An observational study conducted in a tertiary care center of Rajasthan.

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.

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 P value less than 0.05 was considered significant.

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.

DLCO can detect lung function impairment in asymptomatic or mildly symptomatic silica-exposed workers.