Frequency of Radiologic Bronchiolocentric Interstitial Pneumonia Patterns and Associated Factors in Welders

Bronchiolocentric interstitial pneumonia (BIP) is an airway-centered pattern observed in various interstitial lung diseases. This study aimed to evaluate the clinical, occupational, and radiological factors associated with the frequency of the BIP pattern on HRCT in welders.

In this retrospective cross-sectional study, an operational HRCT-based methodology was used to systematically define the BIP pattern in 73 male welders. The frequency of the BIP pattern and its associations with clinical, demographic, and occupational factors were investigated by comparing cases according to BIP status. Cases were compared according to the presence of BIP, which was defined based on operational radiological criteria. Appropriate parametric and nonparametric tests were used for statistical analyses.

The BIP pattern was detected in 21.9% of welders (n = 16; 13 nonfibrotic and 3 fibrotic). Although BIP frequency did not differ significantly between never-smokers and current smokers (13.3% vs. 16.2%; p = 0.102), cumulative smoking exposure was higher among BIP-positive cases (32.5 vs. 20 pack-years; p = 0.021). DLCO and KCO were significantly lower in BIP-positive cases among the 33 patients with available diffusion capacity measurements (p = 0.007 and p = 0.002, respectively). Cases with the BIP pattern also had higher mMRC dyspnea scores (p = 0.032). The most frequent HRCT findings were bronchiolar wall thickening and centrilobular ground-glass nodules.

The BIP pattern is observed at a notable frequency on HRCT in welders. The findings suggest that BIP is not specific to hypersensitivity pneumonitis and may represent a morphological pattern associated with various inhalational etiologies. Occupational history should be carefully assessed in cases exhibiting the BIP pattern.