Association of urine CC16 and lung function and asthma in Chinese children

Background: Many studies have shown the relationship between serum Club cell secretory protein-16 (CC16) and respiratory diseases. However, little research has been done to study urinary CC16 in relation to respiratory diseases. Our objective was to examine the association of urinary CC16 and physician-diagnosed asthma or lung function measurements in Chinese children. Methods: A total of 147 physician-diagnosed children with asthma, ages 9-15 years, were recruited from our cross-sectional study population in northeast China. The 390 healthy children who were not asthmatic and not smokers were selected at random from the population according to 10% proportional sampling. Lung function values, including forced expiratory volume in 1 second and forced vital capacity were measured with two portable spirometers. Urine CC16 was determined by using an enzyme-link immunoassay kit. The relationships between urine CC16 levels and asthma, lung function were assessed by multiple regression models. Results: The geometric mean (95% confidence interval [CI]) creatinine-adjusted urine CC16 level was, for creatinine, 9.77 ng/mg (95% CI, 8.12-12.02 ng/mg). After adjustments for sex, age, body mass index, parental education, and smoking status, lower urine CC16 levels were found to be associated with asthma (odds ratio 0.782 [95% CI, 0.617- 0.990]). A positive association was found between urine CC16 and forced vital capacity (beta 0.064 [95% CI, 0.008-0.119]). Conclusion: Our study demonstrated lower levels of urine CC16 and lung function in patients with asthma than in those patients without asthma. CC16 in urine may be a useful tool or biomarker for investigating lung epithelium integrity among children with asthma or lung injury.