Quantitative CT Patterns and Functional Loss Related to Welding Fume Exposure, While Handling the Confounding Effect...

Ill-defined centrilobular nodules, the most common radiological sign of welding fume (WF) exposure, are also frequently seen in smoking-related respiratory bronchiolitis due to their common pathophysiological features. Thus, smoking is often a confounding factor in the diagnosis of welder's pneumoconiosis. This study aimed to investigate the quantitative computed tomography (QCT) patterns associated with WF exposure, while accounting for the effects of cigarette smoking. Additionally, the relationship between WF exposures and pulmonary function tests (PFTs) was also evaluated as the secondary outcome.

This study involved 136 male employees, comprising 66 welders and 70 controls. The WF exposure index was retrospectively estimated by using a semiquantitative exposure assessment, and cigarette pack-years were noted. Two radiologists, blinded to exposure information, performed QCT analysis, an objective and reproducible method. PFT results were also compared.

A significant decrease in the histogram's skewness and kurtosis was observed with WF exposure, in contrast to the effects of smoking. In multivariate analysis, the percentage of voxels in the range of -949 to -850 HU decreased with WF exposure (p = 0.037), whereas the percentage of voxels greater than -750 HU increased significantly. Each incremental WF exposure index was associated with a 0.39% decrease in predicted FEV1% (forced expiratory volume in the first second) when adjusted for smoking.

We identified functional losses and distinct QCT patterns associated with exposure to WF and cigarette smoke, both of which may cause chronic lung inflammation. These findings may offer valuable insights for further research.