Junior Resident, Department of General Medicine.
Associate Professor, Department of Pulmonary & Critical Care Medicine.
J Assoc Physicians India. 2023 Aug;71(8):11-12. doi: 10.59556/japi.71.0285.
Chronic obstructive lung disease (COPD) has been characterized as a smoker's disease, which has resulted in the usual exclusion of never-smokers from COPD studies. It is now recognized that never-smokers account for nearly one-fourth of all COPD cases, and thus airflow limitation in never-smokers needs further evaluation. Our study aims to elucidate the clinical and physiological aspects of COPD in nonsmokers and to compare smokers and nonsmokers with COPD.
A total of 200 naïve sequential patients with COPD were recruited. The severity of airflow limitation in COPD patients was defined as per Global Initiative for COPD (GOLD) 2019 criteria, and the severity of breathlessness was assessed by the modified Medical Research Council (MRC) dyspnea scale. Data was collected using a patient pro forma, including risk factors for COPD and detailed clinical history. Phenotypic differences along with biomass exposure between never-smokers and smokers were analyzed.
Compared to smokers, never-smokers presented at a younger age (55.69 ± 11.5 years; p < 0.001), with a longer duration of dyspnea (5.05 ± 4.96 vs 7.35 ± 6.98 years, p < 0.01). Chest radiographs revealed hyperinflation in a higher number of smokers as compared to never-smokers (82.9 vs 64.6%, p < 0.05). On spirometry evaluation, smokers were found to have significantly poorer lung function [forced expiratory volume in first second (FEV1) 40.36 ± 17.76%; forced vital capacity (FVC): 58.16 ± 17.02%] as compared to never-smokers (FEV1: 47.1 ± 16.47%; FVC: 67.38 ± 17.02%) with p < 0.05. With respect to severity at presentation, most (45.8%) never-smokers presented with stage 2 COPD as compared to the majority of smokers (46.7%) who presented with stage 3 COPD (p-value of <0.05). Absolute eosinophil count (AEC) and eosinophil proportion in total leucocyte count (TLC) was significantly higher in never-smokers as compared to the smokers (232 ± 204.2 vs 309 ± 238.8, p < 0.05). Risk factor analysis showed mean biomass exposure index was significantly higher in never-smokers as compared to smokers (56.02 vs 6.28; p-value of <0.001).
Compared to smokers, COPD in never-smokers presents at a younger age, with a longer duration of dyspnea and higher eosinophil count. Biomass exposure is one of the major contributors to etiologies for COPD in nonsmokers.
慢性阻塞性肺疾病（COPD）被认为是一种吸烟者的疾病，这导致通常将从不吸烟的人排除在 COPD 研究之外。现在已经认识到，从不吸烟的人几乎占所有 COPD 病例的四分之一，因此需要进一步评估从不吸烟的人的气流受限情况。我们的研究旨在阐明非吸烟者 COPD 的临床和生理方面，并比较吸烟者和非吸烟者的 COPD。
共招募了 200 名患有 COPD 的未经治疗的连续患者。根据全球倡议慢性阻塞性肺疾病（GOLD）2019 标准，COPD 患者气流受限的严重程度被定义，呼吸困难的严重程度通过改良的医学研究委员会（MRC）呼吸困难量表进行评估。使用患者表格收集数据，包括 COPD 的危险因素和详细的临床病史。分析了从不吸烟者和吸烟者之间的表型差异以及生物量暴露情况。
与吸烟者相比，从不吸烟者的年龄更小（55.69 ± 11.5 岁；p < 0.001），呼吸困难的持续时间更长（5.05 ± 4.96 与 7.35 ± 6.98 年，p < 0.01）。与从不吸烟者相比，吸烟者的胸片显示出更高比例的过度充气（82.9%比 64.6%，p < 0.05）。在肺功能评估中，吸烟者的肺功能明显较差[第一秒用力呼气量（FEV1）：40.36 ± 17.76%；用力肺活量（FVC）：58.16 ± 17.02%]与从不吸烟者（FEV1：47.1 ± 16.47%；FVC：67.38 ± 17.02%）相比，p < 0.05。就就诊时的严重程度而言，大多数（45.8%）从不吸烟者表现为 2 期 COPD，而大多数吸烟者（46.7%）表现为 3 期 COPD（p 值 < 0.05）。与吸烟者相比，从不吸烟者的绝对嗜酸性粒细胞计数（AEC）和嗜酸性粒细胞在总白细胞计数（TLC）中的比例明显更高（232 ± 204.2 与 309 ± 238.8，p < 0.05）。风险因素分析显示，从不吸烟者的平均生物量暴露指数明显高于吸烟者（56.02 与 6.28；p 值 < 0.001）。
与吸烟者相比，从不吸烟者的 COPD 发病年龄更小，呼吸困难持续时间更长，嗜酸性粒细胞计数更高。生物量暴露是导致非吸烟者 COPD 发病的主要因素之一。
