Risk factors for airway hyperresponsiveness in severely obese women
AP-HP, Hôpital européen Georges-Pompidou, Service de Physiologie-Clinique de la Dyspnée, 75015 Paris, France. Respiratory Physiology & Neurobiology
(Impact Factor: 1.97).
01/2013; 186(2). DOI: 10.1016/j.resp.2013.01.009
Obesity affects airway diameter and tidal ventilation pattern, which could perturb smooth muscle function. The objective was to assess the pathophysiology of airway hyperresponsiveness in obesity while controlling for gastro-oesophageal reflux disease. Obese women (n=118, mean±SD BMI 46.1±6.8kg/m(-2)) underwent pulmonary function testing (including tidal ventilation monitoring and methacholine challenge) and oesogastro-duodenal fibroscopy. Fifty-seven women (48%, 95% CI: 39% to 57%) exhibited hyperresponsiveness (dose-response slope ≥ 2.39% decrease/μmol) that was independently and positively correlated with predicted % FRC, Raw(0.5) and negatively correlated with sigh frequency during tidal ventilation. Obese women had an increased breathing frequency but a similar sigh frequency than healthy lean women (n=30). Twenty-two obese women (19%, 95% CI: 12% to 26%) were classified as asthmatics (hyperresponsiveness and suggestive symptoms) without confounding effect of gastro-oesophageal reflux disease. In conclusion, in women referred for bariatric surgery, unloading of bronchial smooth muscle (reduced airway caliber and sigh frequency) is associated with hyperresponsiveness.
Available from: PubMed Central
- "Overall, in their study, obesity (BMI ≥ 30 kg/m2) was very prevalent (50 subjects equally distributed between the sexes) and they highlighted the association of NSP with obesity and hyperresponsiveness (31%). Obesity has also been associated with propensity of distal airway closure/hyperresponsiveness . We similarly observed that asthmatic patients in our series were often obese, even if obesity prevalence was lower in our series (26%), which may further explain our lower prevalence of NSP. "
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ATS/ERS Task Force has highlighted that special attention must be paid when FEV1 and FVC are concomitantly decreased (<5th percentile) and the FEV1/FVC ratio is normal (>5th percentile) because a possible cause of this non specific pattern (NSP) is collapse of small airways with normal TLC measured by body plethysmography (>5th percentile). Our objectives were to determine the main lung diseases associated with this pattern recorded prospectively in a lung function testing (LFT) unit, the prevalence of this pattern in our LFT and among the diseases identified, and its development.
Observational study of routinely collected data selected from our Clinical Database Warehouse.
The prevalence of NSP was 841/12 775 tests (6.6%, 95% CI: 6.2 to 7.0%). NSP was mainly associated with seven lung diseases: asthma (prevalence of NSP among asthmatics: 12.6%), COPD/emphysema (prevalence 8.6%), bronchiectasis (12.8%), sarcoidosis (10.7%), interstitial pneumonia (4.0%), pulmonary hypertension (8.9%) and bilateral lung transplantation for cystic fibrosis (36.0%). LFT measurements were described in 185 patients with NSP and indisputable nonoverlapping causes. A moderate defect (FEV1: 66 ± 9% predicted) with mild lung hyperinflation (FRC: 111 ± 27%, RV: 131 ± 33% predicted: suggesting distal airway obstruction) was evidenced whatever the underlying cause. A long term stability of NSP was evidenced in 130/185 patients (70% 95% CI: 64 to 77%).
NSP is observed in asthma, COPD/emphysema, bronchiectasis, sarcoidosis, pulmonary hypertension, interstitial pneumonia and after bilateral lung transplantation and remains stable in the majority of patients.
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Obesity has been associated with a lesser degree of asthma control that may be biased by other comorbidities. The objectives of this cross-sectional study were to describe resting and activity-related dyspnea complaints according to the presence of obesity-related comorbidities (asymptomatic airway hyperresponsiveness (AHR), asthma, gastroesophageal reflux disease (GERD) and sleep-disordered breathing (SDB)). We hypothesized that obese women can exhibit both resting and activity-related dyspnea, independently of the presence of asthma.
Severely obese (body mass index (BMI) > 35 kg m(-2)) women prospectively underwent description of resting and activity-related dyspnea (verbal descriptors and Medical Research Council (MRC) scale), pulmonary function testing (spirometry, absolute lung volumes, and methacholine challenge test), oesogastro-duodenal fibroscopy, and overnight polygraphy. Thirty healthy lean women without airway hyperresponsiveness were enrolled.
Resting dyspnea complaints were significantly more prevalent in obesity (prevalence 41%) than in healthy lean women (prevalence 3%). Chest tightness and the need for deep inspirations were independently associated with both asthma and GERD while wheezing and cough were related to asthma only in obese women. Activity-related dyspnea was very prevalent (MRC score > 1, 75%), associated with obesity, with the exception of wheezing on exertion due to asthma. Asymptomatic AHR and SDB did not affect dyspneic complaints.
In severely obese women referred for bariatric surgery, resting dyspnea complaints are observed in association with asthma or GERD, while activity-related dyspnea was mainly related to obesity only. Consequently, asthma does not explain all respiratory complaints of obese women.
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ABSTRACT: Airway anatomy could be a risk factor for asthma in susceptible patients with airway hyperresponsiveness. This anatomy can be described by only two parameters, the tracheal cross-sectional area and the homothety ratio, which describes the reduction of calibre at each subsequent generation. Thus, we hypothesised that the tracheal area would be linked to the risk of asthma presence. Tracheal area (measured by acoustic reflexion method) and airway responsiveness to metacholine (expressed as Dose Response Slope) were evaluated in 71 consecutive adult patients with nasal polyposis and normal baseline lung function. Hyperresponsiveness was evidenced in 30/71 patients (42%), and 20/71 patients (28%) were asthmatics. Forced expiratory flows were related to tracheal areas (mean value: 3.22±1.32 cm(2)). In a logistic multivariate analysis, tracheal area and the degree of responsiveness were independent predictors of asthma. In conclusion, this study suggests that airway anatomy, crudely assessed by tracheal section, is an independent determinant of asthma.
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