Emphysema and Airflow Obstruction in Non-Smoking Coal Miners with Pneumoconiosis

Abstract

BackgroundAccumulating evidence shows that functional impairment in subjects with coal workers’ pneumoconiosis (CWP) is principally due to emphysema and airflow obstruction, rather than underlying restrictive mechanisms. However, cigarette smoking has remained a major confounder. The aim of this study was to assess whether coal dust exposure was associated with emphysema and/or airflow obstruction in the absence of smoking history.Material/MethodThe subjects evaluated for possible pneumoconiosis between 2013 and 2015 were retrospectively enrolled into this study. After excluding those with history of smoking, tuberculosis, or lung cancer, the study population was a total of 57 subjects. The emphysema severity and airflow obstruction were quantified by computed tomographic densitometry analysis and spirometry, respectively. For comparability regarding emphysema, 9 age- and sex-matched nonsmoker (n=9) control subjects without known lung disease were randomly selected from a radiology database.ResultsEmphysema severity was significantly higher in the CWP group compared with the control group (15% vs. 4%, p<0.001). The median percent emphysema and percentage of those with FEV1/FVC <0.7 was 13% and 37% in subjects with simple CWP and 18% and 67% in subjects with complicated CWP, respectively. Percent emphysema and Perc15 (15th percentile of the attenuation curve) was correlated with FEV1/FVC (r=−0.45, r=−0.47) and FEF25–75 (r=−0.36, r=−0.56), respectively, but not with perfusion score. A linear regression analysis showed that factors associated with emphysema were FEV1/FVC (β=−0.24, p=0.009) and large opacity (β=−3.97, p=0.079), and factors associated with FEV1/FVC were percent emphysema (β=−0.51, p=0.018) and tenure (β=−0.63, p=0.044).ConclusionsOur results support the observation that coal dust exposure is associated with emphysema and airflow obstruction, independent of smoking status.

Prevalence of spirometry-defined airflow obstruction in never-smoking working US coal miners by pneumoconiosis status

“…Additional details on airflow obstruction type (eg, chronic bronchitis and emphysema) would help explain mechanisms of obstructive impairments in never-smoking coal miners with and without CWP. Of interest in non-smoking miners with obstruction is the presence of fibrotic scarring from focal emphysema as it signifies CWP and is not attributed to smoking 3…”

“…Although cigarette smoking is a major risk factor for obstructive lung disease, obstructive disease also occurs in never-smoking coal miners. Furthermore, coal workers’ pneumoconiosis (CWP) is associated with emphysema and airflow obstruction 3. For example, 15% of non-smoking bituminous coal miners in Turkey with radiographic evidence of CWP had emphysema and 51% had airflow obstruction, defined using spirometry measured as the ratio of forced expiratory volume in the first second to forced vital capacity (FEV 1 /FVC)<0.70 3…”

Lung Function Decline after 24 Weeks of Moxa Smoke Exposure in Rats

“…Pulmonary function tests can be used to analyse forced expiratory volume in 1 second/forced vital capacity ratio (FEV1/FVC%), inspiratory resistance (Ri), expiratory resistance (Re), and lung compliance (Cdyn). FEV1/FVC% plays an important role in the judgement of pneumoconiosis, pulmonary function ventilation and obstructive disorders [23]. Airway resistance is a good indication of airway obstruction and helps to determine whether the cause of pulmonary dysfunction is derived from the airways or not [24].…”

Mining is bad for health: a voyage of discovery

“…The development of this severe, preventable, but incurable lung disease among miners depends on the type and grade (rank) of coal being mined, type or site of coal mine, chemical composition of dust, fineness of dust, concentration of dust in the air, length of period of exposure and underlying health status of the exposed worker, possibly including specific genes (Gamble et al 2012;Blackley et al 2014;Han et al 2015;Liu et al 2017;Perret et al 2017). Smoking increases the risk of the disease (Altinsoy et al 2016;He et al 2017), while tuberculosis is commoner in miners with a pneumoconiosis (Leung et al 2012;Mo et al 2013;Ngosa and Naidoo 2016).…”