Woolcock Institute of Medical Research, 431 Glebe Pt Rd., Glebe, NSW 2037, Australia.
Pulm Pharmacol Ther. 2013 Aug;26(4):438-43. doi: 10.1016/j.pupt.2012.05.004. Epub 2012 May 15.
Obesity is associated with poor asthma control, but the reason for this is unclear. Reduction in operating lung volume, as occurs in obesity, and bronchoconstriction, as occurs in asthma, can increase expiratory flow limitation during tidal breathing (EFLt), which may in turn increase respiratory symptoms. The aim of this study was to determine the effect of obesity on EFLt at baseline and after bronchoconstriction in non-asthmatic and asthmatic subjects, and to determine the association between EFLt, and respiratory symptoms. Data from previously published studies in non-asthmatic and asthmatic subjects were reanalyzed using an index of EFLt derived from respiratory system reactance measured by the forced oscillation technique. The analysis showed that during bronchoconstriction both non-asthmatic and asthmatic obese individuals were more likely to develop EFLt than non-obese subjects, despite similar changes in FEV1. Furthermore the index of EFLt was a significant determinant of the severity of breathlessness during challenge in non-asthmatic subjects, and of asthma symptom control in asthmatic subjects following anti-inflammatory treatment. These studies suggest that the combination of bronchoconstriction and low resting lung volume increase the risk of EFLt, and that this altered response to bronchoconstriction may increase the severity of symptoms and lead to worse asthma control.
肥胖与哮喘控制不佳有关，但原因尚不清楚。在肥胖中会发生肺容积减少，在哮喘中会发生支气管收缩，这两者都会在潮式呼吸期间增加呼气流量受限（EFLt），这反过来可能会增加呼吸症状。本研究旨在确定肥胖对非哮喘和哮喘受试者基础状态和支气管收缩后 EFLt 的影响，并确定 EFLt 与呼吸症状之间的关系。使用强迫振荡技术测量呼吸系统电抗得出的 EFLt 指数，对非哮喘和哮喘受试者的先前发表研究的数据进行了重新分析。分析表明，在支气管收缩期间，非肥胖的肥胖非哮喘个体和哮喘个体比非肥胖个体更容易发生 EFLt，尽管 FEV1 有相似的变化。此外，EFLt 指数是非哮喘受试者在挑战期间呼吸困难严重程度的重要决定因素，也是哮喘受试者在接受抗炎治疗后哮喘症状控制的重要决定因素。这些研究表明，支气管收缩和低静息肺容积的组合增加了 EFLt 的风险，而这种对支气管收缩的改变反应可能会增加症状的严重程度，并导致哮喘控制更差。
