Biomarkers for Pulmonary Inflammation and Fibrosis and Lung Ventilation Function in Chinese Occupational Refractory Ceramic Fibers-Exposed Workers

Abstract

Refractory ceramic fibers (RCFs) can cause adverse health effects on workers’ respiratory system, yet no proper biomarkers have been used to detect early pulmonary injury of RCFs-exposed workers. This study assessed the levels of two biomarkers that are related to respiratory injury in RCFs-exposed workers, and explored their relations with lung function. The exposure levels of total dust and respirable fibers were measured simultaneously in RCFs factories. The levels of TGF-β1 and ceruloplasmin (CP) increased with the RCFs exposure level (p < 0.05), and significantly increased in workers with high exposure level (1.21 ± 0.49 ng/mL, 115.25 ± 32.44 U/L) when compared with the control group (0.99 ± 0.29 ng/mL, 97.90 ± 35.01 U/L) (p < 0.05). The levels of FVC and FEV1 were significantly decreased in RCFs exposure group (p < 0.05). Negative relations were found between the concentrations of CP and FVC (B = −0.423, p = 0.025), or FEV1 (B = −0.494, p = 0.014). The concentration of TGF-β1 (B = 0.103, p = 0.001) and CP (B = 8.027, p = 0.007) were associated with respirable fiber exposure level. Occupational exposure to RCFs can impair lung ventilation function and may have the potential to cause pulmonary inflammation and fibrosis. TGF-β1 and CP might be used as sensitive and noninvasive biomarkers to detect lung injury in occupational RCFs-exposed workers. Respirable fiber concentration can better reflect occupational RCFs exposure and related respiratory injuries.

Respiratory effects induced by occupational exposure to refractory ceramic fibers

“…In our previous research, pulmonary ventilation function was also measured among workers exposed to RCFs and controls. However, the results of FVC%, FEV 1 % and FEV 1 /FVC were lower than in this study, probably because the subjects of these two studies were different (Zhu et al, 2017). We have included more workers exposed to RCFs and chosen a different group as controls in this study.…”

“…To clarify the exposure levels of RCF‐exposed workers, concentrations of respirable fibers and total dust in different job categories in these nine workshops were measured simultaneously. Our previous study has already measured the concentration of RCFs in four manufacturing workshops, a textile workshop and a module workshop (Zhu et al, 2017). In the present study, we measured the concentrations of RCFs in three other RCF‐related workshops including board‐making, wet process and paper‐making workshops.…”

“…We conducted at least three full shifts during normal working hours, breathing zone exposure monitoring for each job category. The methods and materials used for air sampling were described in our previous study (Zhu et al, 2017). In summary, a worker from each job category wore two air sampling pumps connected to filters located in the worker's breathing zone to measure both respirable fiber concentration and total dust concentration.…”

“…Forty‐hour (a workweek) time‐weighted average concentration ( C TWA, 40 h ) was estimated for each job. The methods of calculation were also described in the previous study (Zhu et al, 2017).…”

“…Respiratory health effects have been studied among workers exposed to occupational particles such as carbon nanofibers, asbestos and other MMMFs, which are also identified as the primary target outcomes for exposure to RCFs based on toxicological risk assessments (Bernstein, 2007;Moulin et al, 1988;Schubauer-Berigan et al, 2018). Our previous study found there was a significant decrease in lung function and changes in biomarkers among RCFexposed workers (Zhu et al, 2017). However, due to the relatively small sample size and lack of respiratory symptom evaluation, our previous study could not fully interpret the respiratory health effects caused by occupational exposure to RCFs.…”