ABSTRACT
Chronic obstructive pulmonary disease (COPD) is defined by chronic airflow limitation that, in practical terms, requires spirometric assessment and the presence of persistent respiratory symptoms. COPD, emphysema, and chronic bronchitis, even though separate diagnostic entities, are sometimes studied together as a mixed diagnostic group, with condition-specific subcategories stratified insofar as the data allow. An overlap syndrome between asthma and COPD (ACOS) has been categorized as a subtype of COPD. The epidemiological perspective on COPD in relation to occupational factors focuses on associations of risk, most through estimation of relative risk (RR) and a related measure, the odds ratio (OR). The study of occupationally related COPD has also been informed by estimations of population attributable risk percent, which is also known as the population attributable fraction (PAF). The pooled estimate of the occupationally associated PAF of COPD is close to 15% in the general population and to 30% in nonsmokers. The authors present the impact of exposure to inorganic dusts such as coal and silica dusts as well as metal fumes on airflow limitation and COPD. The authors conclude that in the case of COPD and chronic bronchitis, the consistency of findings from multiple studies worldwide, using a variety of analytic approaches in heterogeneous populations and over a wide range of working conditions, strongly supports a causal association between occupational exposures and disease. Therefore, it is reasonable to assume that nearly 15% of COPD (3 in 20 cases) is attributable to work factors.
