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.