Background: Chronic respiratory diseases (asthma, COPD) are commonly associated with obstruction of the small airways (SAO), which has been associated with occupational exposures. However, the survival of people with SAO exposed to harmful occupational agents has not been described. Our aim was to assess the mortality risk related to occupational exposures among people with SAO.

Methods: We used data from UK Biobank participants with SAO and information on lifetime occupational exposures, assigned individually using the ALOHA+ Job Exposure Matrix. Mortality data were provided by the National Death Registries. SAO was defined as a forced expiratory volume in three seconds to the forced expiratory volume in six seconds ratio (FEV₃/FEV₆) below the lower limit of normal. To assess the association of all-cause mortality with lifetime occupational exposures (pesticides; solvents; metals and VGDF: vapours, gases, dusts, fumes) we used Cox Proportional Hazards models adjusted for potential confounders: sex, smoking status, smoking pack-years, Townsend deprivation index, ethnicity and UK Biobank centre. 

Results: Among 13,942 participants there were 457 deaths over a mean of 12.85 years of follow-up. Increased all-cause mortality was greater in those with occupational exposures to VGDF (VGDF_{low exposure} HR = 1.32, 95%CI 1.04-1.78; VGDF_{moderate exposure} HR = 1.41, 95%CI 1.11-1.78). All-cause mortality was not associated with other occupational exposures.

Conclusion: Lifetime exposure to VGDF may increase the risk of early death among people with SAO. This work emphasises the benefit of early intervention to target respiratory morbidity and mortality in working populations.