Exposure to pesticides at work is linked to an increased risk of developing COPD, a large UK population-based study suggests.

Using data from the UK Biobank cohort study, researchers investigated the lifetime job histories of about 100,000 people from the general population and found a cumulative exposure to pesticides was associated with an increased risk of COPD, with positive exposure-response trends.

Ever being exposed to pesticides at work was associated with a 13% increased risk of developing COPD, while high cumulative exposure to pesticides was linked with a 32% increased risk of COPD, according to the study published in Thorax.

The association remained after researchers factored in simultaneous exposure to other agents and in sub-analyses in people without asthma and who had never smoked.

‘The unique large sample, and the confirmation of our results in sensitivity analyses, in particular in never smokers, support the validity of these findings and deserve further investigation,’ the authors said.

‘Future studies focused on evaluating the effect of specific types of pesticides on chronic airway obstruction are warranted in order to inform focused workplace preventive strategies and avoid the associated COPD burden.’

Strengths of the study included its sample size, which researchers believed was larger than any previous study on lifetime occupations and COPD risk in the general population.

Among the study’s limitations, the researchers noted it hadn’t been possible to identify specific pesticide subtypes responsible for the observed increased COPD risk.

‘Occupational exposures are important, preventable causes of COPD, and it has been recently estimated that about 14% of cases are work-related,’ the authors said.

‘Identification of specific occupations and the underlying exposures associated with increased risk of COPD is key to preventing the associated public health burden, both in terms of morbidity and mortality and to focus on preventive strategies.’

A relatively small percentage of cohort members were exposed to pesticides (4.2% among COPD cases and 3.5% among people without COPD).

Most people had been exposed to only low levels in their lifetime career, the study authors noted. No significantly increased risk of COPD was observed for any of the other agents, such as metals, included in the study analysis.

The findings were consistent with a previous study from the same research team where analysing the lifetime job histories of UK Biobank participants they found people who had identified as a gardener, groundsman and park keeper or with a role in agriculture and fishing occupations not classified elsewhere were among the occupations at highest risk of COPD.

It comes after the British Lung Foundation warned that tens of thousands of people could have undiagnosed COPD in the UK.