title: Gastro-oesophageal reflux and worse asthma control in obese children: a case of symptom misattribution?
abstract: BACKGROUND
  Obese children for unknown reasons report greater asthma symptoms. Asthma and obesity both independently associate with gastro-oesophageal reflux symptoms (GORS). Determining if obesity affects the link between GORS and asthma will help elucidate the obese-asthma phenotype.
  
  
  OBJECTIVE
  Extend our previous work to determine the degree of associations between the GORS and asthma phenotype.
  
  
  METHODS
  We conducted a cross-sectional study of lean (20%-65% body mass index, BMI) and obese (≥95% BMI) children aged 10-17 years old with persistent, early-onset asthma. Participants contributed demographics, GORS and asthma questionnaires and lung function data. We determined associations between weight status, GORS and asthma outcomes using multivariable linear and logistic regression. Findings were replicated in a second well-characterised cohort of asthmatic children.
  
  
  RESULTS
  Obese children had seven times higher odds of reporting multiple GORS (OR=7.7, 95% CI 1.9 to 31.0, interaction p value=.004). Asthma symptoms were closely associated with GORS scores in obese patients (r=0.815, p<0.0001) but not in leans (r=0.291, p=0.200; interaction p value=0.003). Higher GORS scores associated with higher FEV1-per cent predicted (p=0.003), lower airway resistance (R10, p=0.025), improved airway reactance (X10, p=0.005) but significantly worse asthma control (Asthma Control Questionnaire, p=0.007). A significant but weaker association between GORS and asthma symptoms was seen in leans compared with obese in the replicate cohort.
  
  
  CONCLUSIONS
  GORS are more likely to associate with asthma symptoms in obese children. Better lung function among children reporting gastro-oesophageal reflux and asthma symptoms suggests that misattribution of GORS to asthma may be a contributing mechanism to excess asthma symptoms in obese children.
authors.affiliation: Division of Pulmonary & Sleep Medicine, Nemours Children's Hospital, Orlando, Florida, USA.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Lang
authors.affiliation: Department of Biomedical Research, Center for Pediatric Research, Alfred I. DuPont Hospital of Children, Wilmington, Delaware, USA.
authors.forename: Jobayer
authors.initials: J
authors.lastname: Hossain
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors.forename: Janet T
authors.initials: JT
authors.lastname: Holbrook
authors.affiliation: Division of Pediatric Respiratory Medicine & Allergy, University of Virginia School of Medicine, Charlottesville, Virginia, USA.
authors.forename: W Gerald
authors.initials: WG
authors.lastname: Teague
authors.affiliation: GI Care for Kids, Children's Center for Digestive Healthcare, Atlanta, Georgia, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Gold
authors.affiliation: Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wise
authors.affiliation: Center for Pharmacogenomics & Translational Research, Nemours Children's Clinic, Jacksonville, Florida, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Lima
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity / Q000639:trends; D003430:Cross-Sectional Studies; D019468:Disease Management; D005260:Female; D005431:Florida / Q000453:epidemiology; D005500:Follow-Up Studies; D005540:Forced Expiratory Flow Rates; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D011379:Prognosis; D011788:Quality of Life; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
keywords: Asthma; Asthma Epidemiology; Asthma Mechanisms; Paediatric asthma; Perception of Asthma/Breathlessness
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