Occupational Exposures: Evidence for a Causal Association with Chronic Obstructive Pulmonary Disease

Abstract

The increase in morbidity and mortality attributable to chronic obstructive pulmonary disease (COPD) has focused attention on environmental and host factors causally associated with the clinical entities included under the rubric of this term with a view to early preventive intervention. Despite the biologic plausibility of inhaled agents being causally implicated, only the role of tobacco smoke has been accepted beyond doubt. However, evidence implicating occupational exposures has accumulated, in particular over the last 2 yr, from: (1) community-based studies (in which larger study populations provide greater power than the usually smaller workforce based studies); (2) longitudinal studies of lung function (which enhance the signal of interest, namely the effects of the occupational exposures, and diminish the noise due to between-individual differences); (3) pathology studies (in which the outcome of interest is the quantitative measurement of emphysema), and (4) cohort mortality studies of all or specific causes of death. This evidence, reviewed here according to accepted criteria for establishing causality, leaves little doubt that occupational exposure to dust and/or to dust and fumes may be causally implicated in the genesis of COPD. As with tobacco exposure, both bronchitis (mucus hypersecretion) and airflow limitation are recognized as causally related to exposure, but not necessarily to each other. As with tobacco exposure, though effects are in general dose related to exposure, there is evidence for individual susceptibility. As with tobacco exposure, a possible host factor is the reactivity of airways to inhaled materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Patients hospitalized for COPD have a high prevalence of modifiable risk factors for exacerbation (EFRAM study)

“…Certain known risk factors for the exacerbation of COPD were found: no influenza vaccination [7] and high air pollution exposure [8]. In addition, other factors were found, related to the poor progress of the disease, that could be considered potential risk factors for exacerbation: no respiratory rehabilitation [9], underprescription of LTOT and noncompliance with it [10,11], current [12] and passive [13] smoking and occupational exposure [14]. Other potentially relevant factors as suggested by members of the study group were: poor inhaler manoeuvres, no pneumococcal vaccination, consumption of alcohol and sedatives, and no physical activity.…”

Occupational chronic obstructive pulmonary disease: a systematic literature review

“…As early as 1985, however, Margaret Becklake concluded that occupational exposure to dust and/or dust and fumes may have a causal link to the pathogenesis of COPD, often relying on studies in which work-related factors were included as confounders to be adjusted for in an analysis of smoking effects (9,10). Coggon and Newman Taylor (11) made an extensive analysis of the literature on airflow obstruction among coal miners, concluding there was a significant association between exposure to coal dust and the development of chronic airflow obstruction.…”

Assessment of Lifetime Occupational Exposure in an Epidemiologic Study of COPD

“…Although cigarette smoking is the most important risk factor worldwide for COPD, occupational exposures to mineral and organic dusts, irritant gases and fumes, and to other industrially produced or used agents have been established as risk factors for COPD [2][3][4][5][6][7][8][9][10][11][12][13][14]. Industryand population-based epidemiological studies have reported increased risk of COPD due to occupational exposures or due to employment in certain industries or job categories.…”

“…Industryand population-based epidemiological studies have reported increased risk of COPD due to occupational exposures or due to employment in certain industries or job categories. Occupational groups reported to have increased risk of COPD include coal miners, hard rock miners, tunnel workers, concretemanufacturing workers, construction workers, agricultural workers, and some manufacturing workers [2,3,[6][7][8][9]. COPD etiology is multi-factorial in nature and is strongly associated with non-occupational factors such as tobacco smoking.…”