Dietary restriction and exercise improve airway inflammation and clinical outcomes in overweight and obese asthma: A randomized trial

Scott, H. A., Gibson, P. G., Garg, M. L., Pretto, J. J., Morgan, P. J., Callister, R. and Wood, L. G. (2013) Dietary restriction and exercise improve airway inflammation and clinical outcomes in overweight and obese asthma: A randomized trial. Clinical and Experimental Allergy, 43 1: 36-49. doi:10.1111/cea.12004


Author Scott, H. A.
Gibson, P. G.
Garg, M. L.
Pretto, J. J.
Morgan, P. J.
Callister, R.
Wood, L. G.
Title Dietary restriction and exercise improve airway inflammation and clinical outcomes in overweight and obese asthma: A randomized trial
Journal name Clinical and Experimental Allergy   Check publisher's open access policy
ISSN 0954-7894
1365-2222
Publication date 2013-01-01
Year available 2013
Sub-type Article (original research)
DOI 10.1111/cea.12004
Volume 43
Issue 1
Start page 36
End page 49
Total pages 14
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2013
Language eng
Abstract Background: Obesity and asthma are associated conditions; however, the mechanisms linking the two remain unclear. Few studies have examined the effects of weight loss on inflammation and clinical outcomes in obese-asthma. Objective: To compare the effects of weight loss achieved by dietary restriction, exercise or combined dietary restriction and exercise on airway inflammation and clinical outcomes in overweight and obese adults with asthma. Methods: Participants (n = 46; 54.3% female, body mass index (mean ± SD) 33.7 ± 3.5 kg/m2) were randomized to complete a 10-week dietary, exercise or combined dietary and exercise intervention. Dual-energy x-ray absorptiometry was performed, the Juniper Asthma Control Questionnaire and Juniper Asthma Quality of Life Questionnaire completed and inflammatory markers, dietary intake and physical activity measured. The trial was registered with the Australian Clinical Trials Registry: ACTRN12611000235909. Results: Retention was 82.6%. Mean ± SD weight loss was 8.5 ± 4.2%, 1.8 ± 2.6% and 8.3 ± 4.9% after the dietary, exercise and combined interventions respectively. Asthma control improved after the dietary (mean ± SD; -0.6 ± 0.5, P ≤ 0.001) and combined interventions (-0.5 ± 0.7, P = 0.040), whereas quality of life improved after the dietary [median (IQR); 0.9 (0.4, 1.3), P = 0.002], exercise [0.49 (0.03, 0.78), P = 0.037] and combined [0.5 (0.1, 1.0), P = 0.007] interventions. A 5-10% weight loss resulted in clinically important improvements to asthma control in 58%, and quality of life in 83%, of subjects. Gynoid adipose tissue reduction was associated with reduced neutrophilic airway inflammation in women [β-coefficient (95% CI); 1.75 (0.02, 3.48), P = 0.047], whereas a reduction in dietary saturated fat was associated with reduced neutrophilic airway inflammation in males (r = 0.775, P = 0.041). The exercise intervention resulted in a significant reduction to sputum eosinophils [median (IQR); -1.3 (-2.0, -1.0)%, P = 0.028]. Conclusion and clinical relevance: This study suggests a weight-loss goal of 5-10% be recommended to assist in the clinical management of overweight and obese adults with asthma. The obese-asthma phenotype may involve both innate and allergic inflammatory pathways.
Keyword Adipose tissue
Asthma
Body composition
Eosinophil
Exercise
Low-energy diet
Neutrophil
Obesity
Weight loss
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Medicine Publications
 
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Created: Fri, 29 May 2015, 23:48:46 EST by Hayley Scott on behalf of Medicine - Princess Alexandra Hospital