title: Does age impact the obese asthma phenotype? Longitudinal asthma control, airway function, and airflow perception among mild persistent asthmatics.
abstract: BACKGROUND
  The relationship between obesity and asthma remains inadequately defined. Studies about how obesity affects asthma control and lung function show conflicting results. Additional focus on the effect of age as a modifier may make clearer the interaction between obesity and asthma phenotype. We sought to use a diverse and well-phenotyped cohort of asthmatic patients to determine how age impacts the relationship between obesity and spirometry, peak flow variability, airflow perception, and asthma control.
  
  
  METHODS
  The characteristics of 490 patients with mild persistent asthma taken from 2,794 study visits from a prospective trial studying strategies of step-down therapy were included in this post hoc analysis. A longitudinal mixed-effect model was used to determine if age affects the relationship between obesity and asthma characteristics, including spirometry, asthma control, airway pH, and perception of airflow changes.
  
  
  RESULTS
  The effect of obesity on asthma outcomes changes with age and gender. Obese 6- to 11-year-old children had the largest reduction in lung function but reported relatively fewer asthma symptoms than did similar nonobese asthmatics. Obese 12- to 17-year-olds showed a trend toward greater airflow obstruction and asthma symptoms compared with nonobese asthmatics. Adults in general displayed few obesity-related alterations in asthma phenotype. Female gender among 12- to 17- and 18- to 44-year-olds was associated with greater obesity-related asthma impairment.
  
  
  CONCLUSIONS
  Age is a significant effect modifier on the relationship between obesity and asthma phenotype. With increasing age, the influence of obesity on the asthma phenotype is generally reduced. The asthma phenotype may be most impacted by obesity among children and women.
  
  
  BACKGROUND
  ClinicalTrials.gov; No.: NCT00156819; URL: www.clinicaltrials.gov.
authors.affiliation: Division of Pulmonology, Allergy and Immunology, Nemours Children's Clinic, Jacksonville, FL; Center for Pharmacogenomics and Translational Research, Nemours Children's Clinic, Jacksonville, FL. Electronic address: jelang@nemours.org.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Lang
authors.affiliation: The Center for Pediatric Research, University of Delaware, Newark, DE; Alfred I. DuPont Hospital of Children, Wilmington, and the Department of Food and Resource Economics, University of Delaware, Newark, DE.
authors.forename: Jobayer
authors.initials: J
authors.lastname: Hossain
authors.affiliation: Pulmonary and Critical Care Medicine, University of Vermont College of Medicine, Burlington, VT.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Dixon
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: David
authors.initials: D
authors.lastname: Shade
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wise
authors.affiliation: Wake Forest University School of Medicine, Winston-Salem, NC.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Peters
authors.affiliation: Center for Pharmacogenomics and Translational Research, Nemours Children's Clinic, Jacksonville, FL.
authors.forename: John J
authors.initials: JJ
authors.lastname: Lima
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000235:genetics; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001249:Asthma / Q000150:complications / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D015992:Body Mass Index; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D020738:Leptin / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D010641:Phenotype; D011237:Predictive Value of Tests; D011379:Prognosis; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D014109:Total Lung Capacity; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018927:Anti-Asthmatic Agents; D020738:Leptin