Sexton Paul, Black Peter, Wu Lian, Sommerville Fay, Hamed Maye, Milne David, Metcalf Patricia, Kolbe John
1Department of Medicine, University of Auckland , Auckland , New Zealand.
COPD. 2014 Feb;11(1):2-9. doi: 10.3109/15412555.2013.800853. Epub 2013 Jul 11.
COPD is often regarded as a smoker's disease. In fact, up to 50% of COPD could be attributable to other causes. Relatively little is known about COPD among nonsmokers, and this group is usually excluded from studies of COPD.
In this cross-sectional case-comparison study, smokers and nonsmokers aged over 45 with COPD (post-bronchodilator FEV1 ≤ 70% predicted, FEV1/FVC ratio < 0.7) were recruited from specialist outpatient clinics and from primary care. Subjects completed a questionnaire and interview, and underwent spirometry, venesection, exhaled nitric oxide (ENO) measurement, allergen skinprick testing, formal lung function testing and high resolution CT.
48 nonsmokers and 45 smokers participated. Asthma was nearly universal among nonsmokers and was the commonest identifiable cause of COPD in that group. Nonsmokers also exhibited a high prevalence of objective eosinophilic inflammation (raised ENO and eosinophil counts, positive skinprick tests). Smokers had more severe airflow obstruction, but respiratory symptom prevalences were similar between groups. Nonsmokers reported greater lifetime burdens of respiratory disease. Nonsmokers' HRCT results showed functional small airways disease, with no significant emphysema in any subject. Previously undiagnosed bronchiectasis was common in both groups (31% and 42%).
Asthma is a very common cause of COPD among nonsmokers. Radiological bronchiectasis is common in COPD; the clinical significance of this finding is unclear.
慢性阻塞性肺疾病（COPD）常被视为一种吸烟者疾病。事实上，高达50%的COPD可能归因于其他原因。非吸烟者中对COPD的了解相对较少，并且该群体通常被排除在COPD研究之外。
在这项横断面病例对照研究中，从专科门诊和基层医疗中招募年龄超过45岁的COPD吸烟者和非吸烟者（支气管扩张剂后第一秒用力呼气容积[FEV1]≤预测值的70%，FEV1/用力肺活量[FVC]比值<0.7）。受试者完成一份问卷和访谈，并接受肺活量测定、静脉穿刺采血、呼出一氧化氮（ENO）测量、变应原皮肤点刺试验、正式肺功能测试和高分辨率CT检查。
48名非吸烟者和45名吸烟者参与研究。哮喘在非吸烟者中几乎普遍存在，并且是该组中COPD最常见的可识别病因。非吸烟者还表现出较高的客观嗜酸性粒细胞炎症患病率（ENO升高和嗜酸性粒细胞计数升高、皮肤点刺试验阳性）。吸烟者有更严重的气流受限，但两组间呼吸道症状患病率相似。非吸烟者报告的终身呼吸系统疾病负担更大。非吸烟者的高分辨率CT结果显示存在功能性小气道疾病，所有受试者均无明显肺气肿。两组中既往未诊断出的支气管扩张均很常见（分别为31%和42%）。
哮喘是导致非吸烟者患COPD的非常常见的原因。放射学上的支气管扩张在COPD中很常见；这一发现的临床意义尚不清楚。
