title: Diet-induced weight loss in obese children with asthma: a randomized controlled trial.
abstract: BACKGROUND
  Obesity is highly prevalent in asthmatic children and associated with worse clinical outcomes. Energy restriction to induce weight loss in asthmatic children has not been investigated in a randomized controlled trial (RCT).
  
  
  OBJECTIVE
  To assess if (1) weight loss can be achieved in obese asthmatic children using a dietary intervention; and (2) changes in asthma outcomes occur following diet-induced weight loss.
  
  
  METHODS
  In a 10-week pilot RCT, obese asthmatic children, aged 8-17 years, were randomized to a wait-list control (WLC) (n = 15) or dietary-intervention group (DIG) (n = 13). Lung function, Asthma Control Questionnaire (ACQ) score, and sputum and systemic inflammation were assessed at baseline and post-intervention. (Australian New Zealand Clinical Trials Registry: ACTRN12610000955011).
  
  
  RESULTS
  Body mass index (BMI) z-score reduced significantly in the DIG vs. the WLC (-0.2 [-0.4, -0.1] vs. 0.0 [-0.1, 0.0], P = 0.014). Expiratory reserve volume (ERV) increased significantly within the DIG, but not compared to the WLC (0.7 [0.0, 1.0] L vs. 0.3 [0.0, 0.8] L, P = 0.355). ACQ improved significantly in the DIG, compared to the WLC (-0.4 [-0.7, 0.0] vs. 0.1 [0.0, 0.6], P = 0.004). Airway and systemic inflammation did not change within the DIG. In comparison, C-Reactive Protein (CRP) increased significantly in the WLC (-0.4 [-0.5, 0.4] vs. 0.7 [-0.1, 1.9], P = 0.037). Change (∆) in BMI z-score correlated with ∆CRP (r = 0.47, P = 0.012) and ∆exhaled nitric oxide (eNO) (r = 0.46, P = 0.034), and ∆ACQ was associated with ∆CRP (r = 0.43, P = 0.029).
  
  
  CONCLUSIONS
  Dietary intervention can induce acute weight loss in obese asthmatic children with subsequent improvements in static lung function and asthma control. Systemic and airway inflammation did not change following weight loss. However, changes in BMI z-score were associated with changes in airway and systemic inflammation and this requires further investigation in a larger RCT. This is the first weight loss RCT conducted in obese asthmatic children. Diet-induced weight loss can achieve significant improvements in clinical outcomes for obese children with asthma.
authors.affiliation: Centre for Asthma and Respiratory Diseases, University of Newcastle, Newcastle, NSW, Australia.
authors.forename: M E
authors.initials: ME
authors.lastname: Jensen
authors.forename: P G
authors.initials: PG
authors.lastname: Gibson
authors.forename: C E
authors.initials: CE
authors.lastname: Collins
authors.forename: J M
authors.initials: JM
authors.lastname: Hilton
authors.forename: L G
authors.initials: LG
authors.lastname: Wood
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000178:diet therapy / Q000473:pathology / Q000503:physiopathology; D015992:Body Mass Index; D031204:Caloric Restriction / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009765:Obesity; D012129:Respiratory Function Tests / Q000379:methods; D011795:Surveys and Questionnaires; D015431:Weight Loss