Mustra Rakic Jelena, Zeng Siyang, Rohdin-Bibby Linnea, Van Blarigan Erin L, Liu Xingjian, Ma Shuren, Kane John P, Redberg Rita F, Turino Gerard M, Oestreicher Stock Eveline, Arjomandi Mehrdad
Center for Tobacco Control Research and Education, University of California, San Francisco, California, United States.
Cardiovascular Research Institute, University of California, San Francisco, California, United States.
Chronic Obstr Pulm Dis. 2022 Jul 29;9(3):377-393. doi: 10.15326/jcopdf.2022.0289.
Prolonged past exposure to secondhand tobacco smoke (SHS) in never-smokers is associated with abnormal lung function and reduced diffusing capacity suggestive of an associated lung tissue injury and damage. The mechanisms by which past SHS exposure may contribute to lung tissue damage are unknown. Elastin is a major constituent of extracellular matrix in lung parenchyma.
To determine whether past exposure to SHS is associated with ongoing lung tissue damage as indicated by elevated elastin degradation products that are linked to lung function.
We measured the plasma levels of elastin degradation markers (EDM) from 193 never-smoking flight attendants with a history of remote SHS exposure in aircraft cabins and 103 nonsmoking flight attendants or sea-level control participants without such history of cabin SHS exposure and examined those levels versus their lung function with adjustment for covariates. The cabin SHS exposure was estimated based on airline employment history and years of the smoking ban enactment.
The median [interquartile range] plasma EDM level for all participants was 0.30 [0.24-0.36] ng/mL with a total range of 0.16-0.65 ng/mL. Plasma EDM levels were elevated in those with a history of exposure to cabin SHS compared to those not exposed (0.33±0.08 versus 0.26±0.06 ng/mL; age- and sex-adjusted <0.001). In those with a history of cabin SHS exposure, higher EDM levels were associated with a lower diffusing capacity (parameter estimate [PE] 95% [confidence interval(CI)]=4.2 [0.4-8.0] %predicted decrease per 0.1 ng/mL increase in EDM; =0.030). Furthermore, EDM levels were inversely associated with forced expiratory volume in 1 second (FEV), FEV to forced vital capacity (FVC) ratio , and forced expiratory flow rate between 25% and 75% ( FEF) (PE [95%CI]=5.8 [2.1-9.4], 4.0 [2.2-5.7], and 12.5 [5.8-19.2] %predicted decrease per 0.1 ng/mL increase in EDM, respectively; <0.001). Plasma EDM mediated a substantial fraction of the association of SHS with FEV, FVC, and FEF (<0.05).
Long after past exposure to SHS, there is ongoing elastin degradation beyond what is expected from the aging process, which likely contributes to lower lung function and a reduced pulmonary capillary bed as seen in chronic obstructive pulmonary disease (COPD).
从不吸烟者过去长期暴露于二手烟（SHS）与肺功能异常及弥散能力降低有关，提示存在相关的肺组织损伤。过去暴露于二手烟可能导致肺组织损伤的机制尚不清楚。弹性蛋白是肺实质细胞外基质的主要成分。
确定过去暴露于二手烟是否与持续的肺组织损伤有关，这种损伤表现为与肺功能相关的弹性蛋白降解产物升高。
我们测量了193名有在飞机客舱长期暴露于二手烟史的从不吸烟的空乘人员以及103名无客舱二手烟暴露史的不吸烟空乘人员或海平面对照参与者的血浆弹性蛋白降解标志物（EDM）水平，并在调整协变量后检查这些水平与他们肺功能的关系。根据航空公司工作经历和吸烟禁令颁布年限估算客舱二手烟暴露情况。
所有参与者血浆EDM水平的中位数[四分位间距]为0.30[0.24 - 0.36]ng/mL，范围为0.16 - 0.65 ng/mL。有客舱二手烟暴露史者的血浆EDM水平高于未暴露者（0.33±0.08对0.26±0.06 ng/mL；年龄和性别调整后<0.001）。在有客舱二手烟暴露史者中，较高的EDM水平与较低的弥散能力相关（参数估计[PE]95%[置信区间(CI)] =每EDM增加0.1 ng/mL预计下降4.2[0.4 - 8.0]%；= 0.030）。此外EDM水平与第1秒用力呼气量（FEV）、FEV与用力肺活量（FVC）比值以及25%至75%用力呼气流量（FEF）呈负相关（PE[95%CI]分别为每EDM增加0.1 ng/mL预计下降5.8[2.1 - 9.4]%、4.0[2.2 - 5.7]%和12.5[5.8 - 19.2]%；<0.001）。血浆EDM介导了二手烟与FEV、FVC和FEF关联的很大一部分（<0.05）。
在过去暴露于二手烟很久之后，存在超出衰老过程预期的持续弹性蛋白降解，这可能导致肺功能降低以及如慢性阻塞性肺疾病（COPD）中所见的肺毛细血管床减少。
