The Nonallergic asthma of obesity: A matter of distal lung compliance

Al-Alwan, A; Bates, JHT; Chapman, DG; Kaminsky, DA; DeSarno, MJ; Irvin, CG; Dixon, AE

The Nonallergic asthma of obesity: A matter of distal lung compliance

Al-Alwan, A Bates, JHT Chapman, DG

Kaminsky, DA DeSarno, MJ Irvin, CG Dixon, AE

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Publication Type:: Journal Article
Citation:: American Journal of Respiratory and Critical Care Medicine, 2014, 189 (12), pp. 1494 - 1502
Issue Date:: 2014-06-15

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Field	Value	Language
dc.contributor.author	Al-Alwan, A	en_US
dc.contributor.author	Bates, JHT	en_US
dc.contributor.author	Chapman, DG https://orcid.org/0000-0002-8211-1817	en_US
dc.contributor.author	Kaminsky, DA	en_US
dc.contributor.author	DeSarno, MJ	en_US
dc.contributor.author	Irvin, CG	en_US
dc.contributor.author	Dixon, AE	en_US
dc.date.issued	2014-06-15	en_US
dc.identifier.citation	American Journal of Respiratory and Critical Care Medicine, 2014, 189 (12), pp. 1494 - 1502	en_US
dc.identifier.issn	1073-449X	en_US
dc.identifier.uri	http://hdl.handle.net/10453/118813
dc.description.abstract	Rationale: The pathogenesis of asthma in obesity is poorly understood, but may be related to breathing at low lung volumes. Objectives: To determine if lung function in obese patients with asthma and control subjects would respond differently to weight loss. Methods: Lung function was evaluated by conventional clinical tests and by impulse oscillometry in female late-onset, nonallergic patients with asthma and control subjects before, and 12 months after, bariatric surgery. Measurements and Main Results: Patients with asthma (n = 10) had significantly lower FEV1 (79.8 ± 10.6 vs. 95.5 ± 7.0%) and FVC (82.4 ± 13.2 vs. 93.7 ± 8.9%) compared with control subjects (n = 13). There were no significant differences in FRC or TLC at baseline. Twelve months after surgery, control subjects had significant increases in FEV1 (95.5 ± 7.0 to 100.7 ± 5.9), FVC (93.6 ± 8.9 to 98.6 ± 8.3%), FRC (45.4 ± 18.5 to 62.1 ± 15.3%), and TLC (84.8 ± 15.0 to 103.1 ± 15.3%), whereas patients with asthma had improvement only in FEV1 (79.8 ± 10.6 to 87.2 ± 11.5). Control subjects and patients with asthma had a significantly different change in respiratory system resistance with weight loss: control subjects exhibited a uniform decrease in respiratory system resistance at all frequencies, whereas patients with asthma exhibited a decrease in frequency dependence of resistance. Fits of a mathematical model of lung mechanics to these impedance spectra suggest that the lung periphery was more collapsed by obesity in patients with asthma compared with control subjects. Conclusions: Weight loss decompresses the lung in both obese control subjects and patients with asthma, but the more pronounced effects of weight loss on lung elastance suggest that the distal lung is inherently more collapsible in people with asthma. Copyright © 2014 by the American Thoracic Society.	en_US
dc.relation.ispartof	American Journal of Respiratory and Critical Care Medicine	en_US
dc.relation.isbasedon	10.1164/rccm.201401-0178OC	en_US
dc.subject.classification	Respiratory System	en_US
dc.subject.mesh	Lung	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Asthma	en_US
dc.subject.mesh	Obesity	en_US
dc.subject.mesh	Weight Loss	en_US
dc.subject.mesh	Lung Compliance	en_US
dc.subject.mesh	Vital Capacity	en_US
dc.subject.mesh	Forced Expiratory Volume	en_US
dc.subject.mesh	Treatment Outcome	en_US
dc.subject.mesh	Models, Statistical	en_US
dc.subject.mesh	Case-Control Studies	en_US
dc.subject.mesh	Follow-Up Studies	en_US
dc.subject.mesh	Prospective Studies	en_US
dc.subject.mesh	Cross-Sectional Studies	en_US
dc.subject.mesh	Adult	en_US
dc.subject.mesh	Middle Aged	en_US
dc.subject.mesh	Female	en_US
dc.subject.mesh	Bariatric Surgery	en_US
dc.title	The Nonallergic asthma of obesity: A matter of distal lung compliance	en_US
dc.type	Journal Article
utslib.citation.volume	12	en_US
utslib.citation.volume	189	en_US
utslib.for	1102 Cardiorespiratory Medicine and Haematology	en_US
utslib.for	1117 Public Health and Health Services	en_US
utslib.for	11 Medical and Health Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	12	en_US
pubs.publication-status	Published	en_US
pubs.volume	189	en_US

Abstract:

Rationale: The pathogenesis of asthma in obesity is poorly understood, but may be related to breathing at low lung volumes. Objectives: To determine if lung function in obese patients with asthma and control subjects would respond differently to weight loss. Methods: Lung function was evaluated by conventional clinical tests and by impulse oscillometry in female late-onset, nonallergic patients with asthma and control subjects before, and 12 months after, bariatric surgery. Measurements and Main Results: Patients with asthma (n = 10) had significantly lower FEV1 (79.8 ± 10.6 vs. 95.5 ± 7.0%) and FVC (82.4 ± 13.2 vs. 93.7 ± 8.9%) compared with control subjects (n = 13). There were no significant differences in FRC or TLC at baseline. Twelve months after surgery, control subjects had significant increases in FEV1 (95.5 ± 7.0 to 100.7 ± 5.9), FVC (93.6 ± 8.9 to 98.6 ± 8.3%), FRC (45.4 ± 18.5 to 62.1 ± 15.3%), and TLC (84.8 ± 15.0 to 103.1 ± 15.3%), whereas patients with asthma had improvement only in FEV1 (79.8 ± 10.6 to 87.2 ± 11.5). Control subjects and patients with asthma had a significantly different change in respiratory system resistance with weight loss: control subjects exhibited a uniform decrease in respiratory system resistance at all frequencies, whereas patients with asthma exhibited a decrease in frequency dependence of resistance. Fits of a mathematical model of lung mechanics to these impedance spectra suggest that the lung periphery was more collapsed by obesity in patients with asthma compared with control subjects. Conclusions: Weight loss decompresses the lung in both obese control subjects and patients with asthma, but the more pronounced effects of weight loss on lung elastance suggest that the distal lung is inherently more collapsible in people with asthma. Copyright © 2014 by the American Thoracic Society.

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http://hdl.handle.net/10453/118813