title: Longitudinal associations between asthma and general and abdominal weight status among Norwegian adolescents and young adults: the HUNT Study.
abstract: BACKGROUND
  In adolescents the temporal directionality to the asthma and adiposity association remains unclear. Asthma may be a consequence of obesity; however, asthma may increase adiposity.
  
  
  OBJECTIVE
  This study aimed to assess the associations between (i) baseline weight status and subsequent asthma and (ii) baseline asthma and subsequent weight status after 4 and 11 years of follow-up (N = 1543 and N = 1596, respectively) using data from three, sequentially enrolled population-based surveys of Norwegians aged 12-30 years from 1995 to 2008.
  
  
  METHODS
  Weight status was defined as general (body mass index) or abdominal (waist circumference) underweight, normal weight, overweight or obesity. Self-report physician-diagnosed asthma defined asthma status.
  
  
  RESULTS
  Over the longitudinal 11-year follow-up, baseline generally overweight or abdominally obese adolescents had increased risk of asthma. Likewise, baseline asthmatics had increased risk of general overweight or abdominal obesity. After sex stratification, these associations were stronger in males. Generally (odds ratio [OR] 1.90; 95% confidence interval [CI] 1.32, 2.73) or abdominally (OR 1.66; 95% CI 1.13, 2.44) overweight males were at increased risk of asthma. Baseline asthmatic males were also at increased risk of general (OR 2.14; 95% CI 1.54, 2.98) and abdominal (OR 1.77; 95% CI 1.27, 2.47) overweight.
  
  
  CONCLUSIONS
  Among Norwegian adolescents, a bidirectional association of asthma and adiposity was observed in males. Each baseline condition increased the risk of the other condition over time. No association was observed in females.
authors.affiliation: Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA.|Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.|Yale Graduate School of Arts and Sciences, New Haven, CT, USA.
authors.forename: K B
authors.initials: KB
authors.lastname: Egan
authors.affiliation: Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA.|Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.|Yale Graduate School of Arts and Sciences, New Haven, CT, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Ettinger
authors.affiliation: Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA.|Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.|Yale Graduate School of Arts and Sciences, New Haven, CT, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: DeWan
authors.affiliation: Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA.|Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.|Yale Graduate School of Arts and Sciences, New Haven, CT, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Holford
authors.affiliation: HUNT Research Centre, Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Norway.
authors.forename: T L
authors.initials: TL
authors.lastname: Holmen
authors.affiliation: Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA.|Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.|Yale Graduate School of Arts and Sciences, New Haven, CT, USA.|Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Bracken
mesh_terms: D050154:Adiposity; D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009664:Norway / Q000453:epidemiology; D056128:Obesity, Abdominal / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D016017:Odds Ratio; D050177:Overweight; D055105:Waist Circumference; D055815:Young Adult
keywords: Adolescents; asthma; obesity; overweight