Tsuda Yasunari, Noguchi Toshiyuki, Mochizuki Hideaki, Makino Fumihiko, Nanjo Yuta, Sawabe Motoji, Takahashi Hideki
Division of Respiratory Medicine, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan.
Respirology. 2009 May;14(4):529-36. doi: 10.1111/j.1440-1843.2009.01533.x.
Little is known about the aetiology and clinical characteristics of COPD among people who have never smoked.
A case-control study was conducted to describe the potential risk factors for clinically significant COPD among smokers and people who had never smoked. Medical record reviews and scoring of high-resolution computed tomography (HRCT) findings were performed in patients with clinically significant COPD (defined as having post-bronchodilator FEV(1)/FVC < 0.7 and FEV(1) < 60% of the predicted values). Pathological analyses were performed in some patients following autopsy.
Among the 9493 subjects screened, 424 (4.5%) were diagnosed with clinically significant COPD. Forty-nine (11.6% of clinically significant COPD) were never smokers (NSCOPD), and a comparative group of 98 smoking patients with COPD was randomly selected (SMCOPD). NSCOPD was characterized by predominantly female sex (87.8%) and a high prevalence of physician-diagnosed asthma (61.2%). Similar levels of reduction in %FEV(1) and %FEF(25-75%) were found in NSCOPD and SMCOPD, but there were higher %DL(CO) values and fewer low attenuation areas on HRCT in NSCOPD. More than half of the NSCOPD patients without a history of asthma had features of asthma. More than one-third of NSCOPD patients with an asthma history had never had a severe attack. At autopsy, both NSCOPD and SMCOPD showed wall thickening and inflammatory cell infiltration in small airways, and the number of CD4(+)-T cells was increased in NSCOPD.
In elderly Japanese, COPD among never smokers is largely attributable to asthma. Airflow limitation in NSCOPD results from small airway disease (airway predominant phenotype) rather than parenchymal destruction (emphysematous phenotype).
对于从不吸烟人群中慢性阻塞性肺疾病（COPD）的病因及临床特征，人们了解甚少。
开展一项病例对照研究，以描述吸烟者和从不吸烟人群中具有临床意义的COPD的潜在危险因素。对具有临床意义的COPD患者（定义为支气管扩张剂后FEV(1)/FVC < 0.7且FEV(1) <预测值的60%）进行病历回顾及高分辨率计算机断层扫描（HRCT）结果评分。部分患者在尸检后进行病理分析。
在9493名筛查对象中，424人（4.5%）被诊断为具有临床意义的COPD。49人（占具有临床意义的COPD患者的11.6%）从不吸烟（非吸烟COPD，NSCOPD），并随机选取98名吸烟的COPD患者作为对照组（吸烟COPD，SMCOPD）。NSCOPD的特征为女性占主导（87.8%）且医生诊断的哮喘患病率高（61.2%）。NSCOPD和SMCOPD的FEV(1)%和FEF(25 - 75)%降低水平相似，但NSCOPD的DL(CO)%值更高且HRCT上的低衰减区域更少。超过一半无哮喘病史的NSCOPD患者具有哮喘特征。超过三分之一有哮喘病史的NSCOPD患者从未发生过严重发作。尸检时，NSCOPD和SMCOPD均显示小气道壁增厚和炎性细胞浸润，且NSCOPD中CD4(+) - T细胞数量增加。
在老年日本人中，从不吸烟人群的COPD很大程度上归因于哮喘。NSCOPD中的气流受限是由小气道疾病（气道为主型表型）而非实质破坏（肺气肿型表型）导致的。
