Association of respiratory health with occupational exposures in the Burden of Obstructive Lung Disease (BOLD) cohort: a multinational longitudinal study

BACKGROUND: Occupational exposures are contributors to chronic respiratory diseases, particularly in low- and middle-income countries (LMICs), where regulatory policies are limited. We investigated associations between occupational exposures and respiratory outcomes using longitudinal data from the Burden of Obstructive Lung Disease study. METHODS: We analysed data from 4237 participants across 17 sites, mostly in LMICs. Occupational exposures were assessed by self-report (never vs ever) and the ALOHA+Job Exposure Matrix for vapours, gases, dusts, fumes (VGDF), pesticides, solvents and metals (cumulative exposure). Respiratory outcomes included: forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), the FEV₁/FVC and respiratory symptoms. Associations were examined using multilevel linear and logistic regression models adjusted for age, sex, smoking, pack-years, education, body mass index and baseline FVC. We further explored sex differences and non-linear relationships for symptoms. RESULTS: Over a median 10 years of follow-up, FEV₁/FVC decline was associated with moderate (β=-1.34; 95% CI -2.32 to -0.35) and high (β=-1.79; 95% CI -3.33 to -0.20) exposure to VGDF and low (β=-1.11; 95% CI -2.11 to -0.08) and high (β=-2.16; 95% CI -4.08 to -0.24) exposure to pesticides. Increased risk of wheeze was associated with moderate (Relative Risk (RR) =1.45; 95% CI 1.05 to 2.15) and high (RR=1.89; 95% CI 1.100 to 3.26) exposure to pesticides. Associations did not differ by sex. There was weak evidence of non-linear exposure-response relationships and no associations with solvents or metals. CONCLUSIONS: A significant decline in FEV1/FVC was associated with exposure to VGDF and pesticides. Increased risk of wheeze was also associated with exposure to pesticides. These findings underscore the need for continued monitoring in high-exposure settings, particularly in LMICs.