title: Obesity, asthma prevalence and IL-4: Roles of inflammatory cytokines, adiponectin and neuropeptide Y.
abstract: BACKGROUND
  Obesity is associated with asthma risk and severity, but the underlying biological mechanisms are poorly understood. We hypothesized that cytokine markers of systemic inflammation, and adiponectin and neuropeptide Y (NPY) markers of immuno-modulating and neurohormonal regulation are involved in the obesity-asthma association.
  
  
  METHODS
  We explored the relationships between body mass index (BMI), C-reactive protein (CRP), IL-6, TNF-α, adiponectin and NPY with asthma prevalence and IL-4 levels in 70 youth with asthma and 69 age- and gender-matched healthy controls using cross-sectional and longitudinal data.
  
  
  RESULTS
  Mean BMI level was higher among patients with asthma than healthy controls (p < 0.001). In logistic regression models controlling for potential confounders, independent associations with asthma prevalence were found for obesity (p = 0.001), increasing tertiles of CRP (linear trend p < 0.001), IL-6 (linear trend p < 0.001) and lowest and highest tertiles of TNF-α (quadratic trend p < 0.05), increasing adiponectin (linear p = 0.022) and decreasing tertiles of NPY (linear trend p = 0.001). Among patients with asthma, NPY level was positively correlated with adiponectin (p < 0.05) and TNF-α (p < 0.05), and levels of NPY and IL-6 were significantly associated with IL-4 level at baseline and 1-year follow-up.
  
  
  CONCLUSIONS
  The obesity-asthma association was not explained by systemic inflammation. Specifically, CRP, TNF-a, IL-6, NPY and adiponectin were independently associated with asthma prevalence. NPY and IL-6 were associated with IL-4 marker of allergic airway inflammation in asthma and should be further investigated as prognostic markers of asthma outcomes.
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore City, Singapore.|Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.
authors.forename: Hugo P S
authors.initials: HP
authors.lastname: Van Bever
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Medicine, National University Health System, Singapore City, Singapore.
authors.forename: Tow Keang
authors.initials: TK
authors.lastname: Lim
authors.affiliation: Emergency Medicine Department, National University Health System, Singapore City, Singapore.
authors.forename: Win Sen
authors.initials: WS
authors.lastname: Kuan
authors.affiliation: Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.
authors.forename: Daniel Yam Thiam
authors.initials: DY
authors.lastname: Goh
authors.affiliation: Emergency Medicine Department, National University Health System, Singapore City, Singapore.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Mahadevan
authors.affiliation: Emergency Medicine Department, National University Health System, Singapore City, Singapore.
authors.forename: Tiong Beng
authors.initials: TB
authors.lastname: Sim
authors.affiliation: Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.
authors.forename: Roger
authors.initials: R
authors.lastname: Ho
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore City, Singapore.
authors.forename: Anis
authors.initials: A
authors.lastname: Larbi
authors.affiliation: Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.
authors.forename: Tze Pin
authors.initials: TP
authors.lastname: Ng
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001249:Asthma / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D015847:Interleukin-4 / Q000097:blood*; D016014:Linear Models; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D009478:Neuropeptide Y / Q000097:blood*; D009765:Obesity / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; D015415:Biomarkers; C508598:IL4 protein, human; D018836:Inflammation Mediators; D009478:Neuropeptide Y; D015847:Interleukin-4
keywords: adiponectin; adiposity; asthma control; inflammation; neuropeptide Y