Large-scale Study Finds that 21% of COPD Cases Can Be Attributed to Occupational Exposures

A new study showed that 21% of chronic obstructive pulmonary disease (COPD) cases can be attributed to occupational exposures, particularly exposure to biological dust, pesticides, gases, and fumes.

The study, “Occupational exposures and 20-year incidence of COPD: the European Community Respiratory Health Survey,” was published in the journal Thorax.

COPD is a progressive respiratory disease caused by obstruction of the lung airways. While tobacco smoking is known to be the primary risk factor for COPD, many other environmental factors, including occupational exposures, have been implicated in COPD development.

Many studies have examined the relationship between occupation and COPD-related outcomes, and have demonstrated that about 15% of COPD cases can be attributed to exposures at the workplace, even when taking smoking into account.

“Our results strengthen this evidence base substantially,” Jan-Paul Zock, PhD, lead author of the study, said in a press release.

Using the European Community Respiratory Health Survey (ECRHS), an international team led by researchers at the Barcelona Institute for Global Health examined the effects of occupational exposures on COPD incidence. The  ECRHS is a large, multicenter, population-based study with a long follow-up duration.

Individuals from the general population, ages 20-44, were randomly selected between 1991-1993 and followed up 20 years later. Spirometry, a method to assess lung function, was performed when individuals were selected and at follow-up.

In total, 3,343 participants from 12 countries were included in the study, of whom 89 had COPD at follow-up, resulting in an incidence of 1.4 cases per 1,000 person-years.

Interestingly, researchers discovered that participants who were exposed to biological dust had a higher incidence of COPD than those who were unexposed. In fact, individuals who were exposed to biological dust had a 1.6 times higher risk of developing COPD than the general population.

“To our knowledge, this is the first study to demonstrate an effect of biological dust exposure on the incidence of COPD in a prospective fashion in a general population cohort,” Zock said.

Additionally, individuals who were exposed to gases and fumes had a 1.5 times higher risk of developing COPD, and individuals exposed to pesticides had a 2.2 times higher risk of developing COPD.

Statistical analysis revealed that 21% of COPD cases could be attributed to occupational exposures. “This suggests that up to one in five new COPD cases among middle-aged people in Western countries could be prevented by avoiding or controlling occupational exposures in contemporary jobs,” the researchers wrote in the study.

One of the limitations of the study is that the population was still at a fairly young age at follow-up, and COPD generally develops in an older population. However, the fact that some individuals developed COPD due to occupational exposure even among this relatively young population is very troubling from a public health point of view.

A question that remains unanswered is whether the observed effects are modified by smoking, given that smoking is a primary risk factor for COPD development.

“Future studies should clarify whether these effects are modified by smoking, their interplay with asthma, and further detail the risks involved with respect to particular occupations, activities and noxious agents,” the team concluded.