title: Childhood overweight and asthma symptoms, the role of pro-inflammatory proteins.
abstract: BACKGROUND
  Systemic inflammation is suggested as a mechanism by which overweight might induce asthma. However, few studies have linked childhood overweight, inflammation and asthma.
  
  
  OBJECTIVE
  To study the association between body mass index (BMI), asthma symptoms and pro-inflammatory proteins.
  
  
  METHODS
  High-sensitivity C-reactive protein (hs-CRP), complement factor 3 (C3) and 4 (C4) concentrations, and body weight and height were available for 359 4-year-old children participating in the Prevention and Incidence of Asthma and Mite Allergy birth cohort study. Data on asthma symptoms were obtained by yearly questionnaires. Logistic regression and generalized estimating equations were used to analyse the cross-sectional and prospective associations between BMI, asthma symptoms and pro-inflammatory proteins.
  
  
  RESULTS
  BMI was associated with asthma symptoms {odds ratio [OR] 1.43 [95% confidence interval (CI): 1.08-1.88] per BMI standard deviation scores [SDS]}. The inclusion of hs-CRP, C3 and C4 in the statistical models did not change this association. C3 was cross-sectionally associated with frequent asthma symptoms [OR per interquartile range of C3: 1.97 (95% CI: 1.20-3.24)] and prospectively with asthma symptoms [OR: 1.48 (95%CI: 1.04-2.09)], independent of BMI SDS.
  
  
  CONCLUSIONS
  We showed no evidence for a role of hs-CRP, C3 and C4 in the association between BMI and asthma symptoms. C3 concentrations were associated with (frequent) asthma symptoms, independent of BMI.
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands. marga.bekkers@rivm.nl
authors.forename: M B M
authors.initials: MB
authors.lastname: Bekkers
authors.forename: B
authors.initials: B
authors.lastname: Brunekreef
authors.forename: J C
authors.initials: JC
authors.lastname: de Jongste
authors.forename: M
authors.initials: M
authors.lastname: Kerkhof
authors.forename: H A
authors.initials: HA
authors.lastname: Smit
authors.forename: D S
authors.initials: DS
authors.lastname: Postma
authors.forename: U
authors.initials: U
authors.lastname: Gehring
authors.forename: A H
authors.initials: AH
authors.lastname: Wijga
mesh_terms: D001249:Asthma / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology / Q000503:physiopathology; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D002675:Child, Preschool; D015331:Cohort Studies; D003176:Complement C3 / Q000378:metabolism*; D003181:Complement C4 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism; D016014:Linear Models; D008297:Male; D050177:Overweight / Q000150:complications*; D011446:Prospective Studies
chemical_list: D003176:Complement C3; D003181:Complement C4; D002097:C-Reactive Protein