Association of Serum Clara Cell Protein with Pulmonary Function in Occupational Populations with High-PM_2.5 Exposure

Objectives The aim was to investigate the association of serum clara cell protein (CC16) and pulmonary function in occupational populations with high fine particulate matter (PM_2.5) exposure.

Methods We selected 390 male coke oven workers as the exposure group, of whom 215 workers in low-PM_2.5group and 175 workers in high-PM_2.5 group, then selected 115 non exposed workers as the control group. Enzyme-linked immunosorbent assay (ELISA) method was used to detected the serum CC16 levels, and the pulmonary function was measured by spirometer.

Results With the increase of PM_2.5 exposure level, serum CC16 levels reduced (P=0.019). There was a positive correlation between FEV₁/FVC and serum CC16 levels (r=0.094, P=0.035). There also was a positive correlation between FEV₁/FVC and serum CC16 levels (P=0.045) in total population after simple linear regression adjusted age, height, weight, drinking and smoking. After stratification by smoking, the subjects showed a positive correlation between FEF_25%~75%%, FEV₁/FVC and serum CC16 levels in non-smokers. However, there was no any correlation between lung function and serum CC16 levels among the smokers. After age stratification, the authors found a positive correlation between FEF_25%~75%%, FEV₁%, FEV₁/FVC and serum CC16 levels in population younger than 36 years (P values were 0.032, 0.036 and 0.029, respectively). However, the authors did not find similar correlation among population who is older than 36 years.

Conclusions There is significant correlation between serum CC16 level and lung function in population with high PM_2.5 exposure. The decrease of serum CC16 levels could be used as a marker for lung injury caused by high-PM_2.5 exposure.