Association between dust exposure and lung function levels in steelworkers: mediation analysis of inflammatory biomarkers.

Abstract

Purpose: This investigation aimed to examine the mediating effect of inflammatory biomarkers on the relationship between dust exposure and lung function levels among steelworkers.

Methods: The study comprised 2,315 front-line workers employed at an iron and steel company in Tangshan, who underwent occupational health assessments through cluster sampling. Demographic and lifestyle data were collected via a self-administered questionnaire, while physical examinations measured parameters such as height and weight. Lung function was assessed using a portable pulmonary function tester (CHEST). Blood cell counts were uniformly analyzed using a Mindray fully automated biochemistry analyzer (BS-800). Inflammatory biomarkers, including leukocyte count, neutrophil count, lymphocyte count, and platelet count, were assessed, and the neutrophil-to-lymphocyte ratio and systemic immune inflammation index were computed. Generalized linear models and Spearman rank correlation analyses were employed to explore the interplay among dust exposure, inflammatory biomarkers, and alterations in lung function. A mediation analysis model was constructed to elucidate how inflammatory biomarkers mediate the relationship between dust exposure and lung function levels.

Results: After adjusting for covariates, dust exposure was significantly associated with reduced lung function levels, with statistically significant differences observed between dust-exposed and non-exposed groups across various lung function indicators (P < 0.001). In the dust-exposed group, inflammatory biomarkers were elevated, showing significant correlations with FVC and FEV₁ (P < 0.05). However, the correlation between FEV₁/FVC and various inflammatory biomarkers was insignificant (P > 0.05). Mediation analysis revealed that white blood cells and neutrophils partially mediated the association between dust exposure and FVC, with proportions of 1.75% and 1.09%, respectively. Similarly, white blood cells, neutrophils, and the systemic immune inflammation index partially mediated the association between dust exposure and FEV₁, with proportions of 1.15%, 0.82%, and 0.82%, respectively.

Conclusion: In conclusion, dust exposure poses a risk for decreased lung function levels. Inflammatory biomarkers derived from blood cells offer a valuable and easily obtainable means of identifying changes in lungfunction levels. Among these biomarkers, white blood cells, neutrophils, and the systemic immune inflammation index significantly mediate the association between dust exposure and lung function levels, although further exploration is needed to understand their underlying mechanisms.