title: Environmental tobacco smoke exposure, urine CC-16 levels, and asthma outcomes among Chinese children.
abstract: BACKGROUND
  Previous studies have shown the relationship between club cell secretory protein (Clara) (CC-16) and respiratory diseases. However, few studies have explored the associations between urine CC-16 levels and environmental tobacco smoke (ETS) exposure in children. The objective of this study was to evaluate whether ETS exposure is associated with CC-16 when stratified by asthma status.
  
  
  METHODS
  In our study, CC-16 was measured on 537 children aged 9-15 from northeast China in 2011-2012 using the Human Clara Cell Protein ELISA kits. Doctor-diagnosed asthma was defined as having ever been diagnosed with asthma by a physician. The relationship between ETS exposure and urine CC-16 level was assessed using linear regression.
  
  
  RESULTS
  When stratified by asthma status, a negative association between ETS exposure and urine CC-16 was observed after adjusting for the effects of the related covariates, with an adjusted β coefficient [P value] = -0.31 [0.006] in the first 2 years of life and with an adjusted β coefficient [P value] = -0.68 [0.004] in the first 2 years of life and current.
  
  
  CONCLUSIONS
  Our study shows long-term exposure to ETS was associated with urinary CC-16 among children without asthma.
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning, China.
authors.forename: Y-N
authors.initials: YN
authors.lastname: Ma
authors.forename: Z
authors.initials: Z
authors.lastname: Qian
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: E
authors.initials: E
authors.lastname: Rodemich
authors.forename: Y L
authors.initials: YL
authors.lastname: Lee
authors.forename: X-F
authors.initials: XF
authors.lastname: Lv
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: M-M
authors.initials: MM
authors.lastname: Huang
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: Q-C
authors.initials: QC
authors.lastname: He
authors.forename: G-H
authors.initials: GH
authors.lastname: Dong
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology / Q000209:etiology* / Q000652:urine*; D002648:Child; D002681:China / Q000453:epidemiology; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D063868:Patient Outcome Assessment; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014598:Uteroglobin / Q000652:urine*
chemical_list: D014028:Tobacco Smoke Pollution; D014598:Uteroglobin; D003404:Creatinine
keywords: Clara cell secretory protein-16; asthma; children; environmental tobacco smoke exposure