Introduction Occupational exposures are important, preventable causes of chronic obstructive pulmonary disease (COPD). We previously found an increased COPD risk among six occupations by analysing lifetime job-histories and lung function data in the population-based UK Biobank cohort.

Objectives We aimed to build upon these findings and elucidate the underlying potential causal agents.

Methods We applied the ALOHA+ job-exposure matrix (JEM) based on ISCO-88 codes in which exposure to 12 selected agents was rated as 0 (no exposure), 1 (low), and 2 (high). Agents highly correlated (>85%) were combined. COPD was spirometrically-defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < lower limit of normal (LLN). We calculated semi-quantitative cumulative exposure (CE) estimates for each agent by multiplying duration of exposure and squared intensity. Prevalence ratios (PR) and 95% confidence intervals (CI) for COPD were estimated using robust Poisson regression adjusted for centre, sex, age, smoking, and co-exposure to the other JEM agents. Only associations confirmed among never-smokers and never-asthmatics were considered reliable.

Results Out of 116,375 participants with complete job-histories, 94,514 had acceptable/repeatable spirometry data and smoking information and were included in the analysis. Pesticides exposure showed increased COPD risks (PR=1.00, 95%CI 0.85–1.17 for low CE, PR=1.32, 95% CI 1.12–1.56 for high CE; P-trend=0.004), that were confirmed among never-smokers (P-trend=0.005) and never-asthmatics (P-trend=0.001). Results remained unchanged when never-exposed to any of the JEM agents were used as reference category.

Conclusion Focussed preventive strategies in workers exposed to pesticides are warranted to prevent the associated occupational COPD burden.