Long Jia Wei, Jiang Yong Liang
Department of Respiratory Medicine, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, China.
J Clin Med Res. 2024 May;16(5):220-231. doi: 10.14740/jocmr5158. Epub 2024 May 29.
Small airway dysfunction (SAD) and airway inflammation are vital in asthma exacerbations. Type 2 inflammation (T2), mediated by cytokines from T helper 2 cell (Th2) such as interleukin (IL)-4, IL-5, and IL-13, is a potential mechanism underlying SAD. Research on small airway function in asthma is limited. We aimed to explore the correlation between small airway function and respiratory symptoms and comorbidity in T2 and non-T2 asthma.
Derived from the National Health and Nutrition Examination Survey (NHANES), our study encompassed 2,420 asthma patients aged 6 - 79 years, including pulmonary function (PF) data such as forced expiratory flow between 25% and 75% of forced vital capacity (FEF), forced expiratory volume in 1 second (FEV), forced expiratory volume in 3 seconds (FEV), forced expiratory volume in 6 seconds (FEV), and forced vital capacity (FVC). To evaluate the small airway function, we calculated z-scores for FEF, FEF/FVC, FEV/FEV, and FEV/FEV. Logistic regression determined the adjusted odds ratios (aORs) for symptoms and comorbidity.
FEF, FEV/FEV, and FEV/FEV correlated with asthmatic symptoms. FEF had the strongest association with wheezing or whistling attacks. An increase of 1 standard deviations (SD) in FEF reduced recurrent wheezing (aOR: 0.70; 95% confidence intervals (95% CIs): 0.65 - 0.76) and severe attacks (aOR: 0.67; 95% CI: 0.62 - 0.94). These indices were also linked to dry cough and hay fever, particularly FEV/FEV reducing hay fever risk (aOR: 0.70; 95% CI: 0.55 - 0.91) in non-T2 asthma. FEF/FVC related to persistent (aOR: 0.78; 95% CI: 0.72 - 0.84) and severe attacks (aOR: 1.14; 95% CI: 1.08 - 1.22) in non-T2 groups. Lower indices combined with T2 exposure raised severe attack risk.
In this nationwide study, small airway function correlated with symptom onset, especially in T2 asthma. Small airway injury differed between T2 and non-T2 asthma. Prospective research is needed to establish reference values.
小气道功能障碍（SAD）和气道炎症在哮喘急性发作中至关重要。由辅助性T细胞2（Th2）分泌的细胞因子如白细胞介素（IL）-4、IL-5和IL-13介导的2型炎症（T2）是SAD潜在的发病机制。关于哮喘患者小气道功能的研究有限。我们旨在探讨T2和非T2哮喘中小气道功能与呼吸道症状及合并症之间的相关性。
本研究数据来源于美国国家健康与营养检查调查（NHANES），纳入了2420例年龄在6至79岁的哮喘患者，包括肺功能（PF）数据，如用力肺活量25%至75%之间的呼气流量（FEF）、第1秒用力呼气量（FEV₁）、第3秒用力呼气量（FEV₃）、第6秒用力呼气量（FEV₆）和用力肺活量（FVC）。为评估小气道功能，我们计算了FEF、FEF/FVC、FEV₃/FEV₁和FEV₆/FEV₁的z分数。采用逻辑回归分析确定症状和合并症的调整比值比（aOR）。
FEF、FEV₃/FEV₁和FEV₆/FEV₁与哮喘症状相关。FEF与喘息或哮鸣发作的关联最强。FEF每增加1个标准差（SD），复发性喘息风险降低（aOR：0.70；95%置信区间（95%CI）：0.65 - 0.76），严重发作风险降低（aOR：0.67；95%CI：0.62 - 0.94）。这些指标还与干咳和花粉症有关，尤其是在非T2哮喘中，FEV₆/FEV₁降低了花粉症风险（aOR：0.70；95%CI：0.55 - 0.91）。在非T2组中，FEF/FVC与持续性发作（aOR：0.78；95%CI：0.72 - 0.84）和严重发作（aOR：1.14；95%CI：1.08 - 1.22）相关。较低的指标与T2暴露共同增加了严重发作风险。
在这项全国性研究中，小气道功能与症状发作相关，尤其是在T2哮喘中。T2和非T2哮喘的小气道损伤存在差异。需要进行前瞻性研究以建立参考值。
