OBESITY IS A DETERMINANT OF ASTHMA CONTROL, INDEPENDENT OF INFLAMMATION AND LUNG MECHANICS.
Chest. 2011 Mar 17;
Authors: Farah CS, Kermode JA, Downie SR, Brown NJ, Hardaker KM, Berend N, King GG, Salome CM
ABSTRACT BACKGROUND: It is unclear why obesity is associated with worse asthma control. We hypothesized that: (1) obesity affects asthma control independent of spirometry, airway inflammation and airway hyperresponsiveness (AHR); and (2) residual symptoms after resolution of inflammation are due to obesity-related changes in lung mechanics METHODS: 49 asthmatic subjects performed the following, before and after 3 months high-dose inhaled corticosteroid (ICS) treatment: asthma control questionnaire (ACQ-5), spirometry, exhaled nitric oxide (F(E)NO), methacholine challenge and the forced oscillation technique (FOT), which allows for the calculation of respiratory system resistance (Rrs) and reactance (Xrs) as indicators of airway calibre and elastic load, respectively. The effects of treatment were assessed by BMI group (18.5-24.9, 25-29.9, ?30 kg.m(-2)) using ANOVA. Multiple regression analyses determined the independent predictors of ACQ-5. RESULTS: At baseline, the independent predictors of ACQ-5 were FEV(1), F(E)NO and BMI (model r(2) = 0.38, p < 0.001). After treatment, asthma control, spirometry, airway inflammation and AHR improved similarly across BMI groups. The independent predictors of ACQ-5 after treatment were Rrs and BMI (model r(2) = 0.42, p < 0.001). CONCLUSIONS: BMI is a determinant of asthma control independent of airway inflammation, lung function and AHR. After ICS treatment, BMI again predicts ACQ-5, but independent of obesity-related changes in lung mechanics.
PMID: 21415135 [PubMed – as supplied by publisher]
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