The effect of organic dust exposure on change in lung function – A systematic review

Abstract

Background: Lung function is a predictor of morbidity and mortality and the chronic nature of lung function decline facilitates preventive initiatives. Pro-inflammatory microbial constituents of organic dust are considered a cause of respiratory disease. The aim of this systematic review was to explore the impact of organic dust exposure on change in lung function. Methods: The literature search was performed according to the PRISMA criteria using three online databases (PubMed/Embase/Cochrane). Based on predefined inclusion/exclusion criteria concerning study-design (longitudinal, ≥1 year follow-up, ≥50 exposed), exposure-measures (organic dust: wood-work, grain-work, cotton-work, farming), and outcome-measures (change in lung function: FEV1, FVC, FEV1/FVC), 1580 potentially relevant publications were narrowed down to 20 papers. Quality was evaluated based on 6 criteria (maximum score 6). Results: Ten studies had a total quality score of 5-6 and ten studies a score of 3-4. Overall, 14 studies (7 qual. 5-6/7 qual. 3-4) found an association between exposure to organic dust and change in lung function. The effect size ranged from -12.1 mL/yr to -38 mL/yr in excess FEV1 decline, and -9.2 mL/yr to -33.5 mL/yr in excess FVC decline in dust exposed compared to controls. Of 18 studies (10/8) with exposure-response analysis, 12 (7/5) revealed a significant exposure–response relation between organic dust and change in lung function. Conclusion: The studies included were of varying design, applied different measures of exposure and outcome, and were of different size. The results were inconsistent, though they point toward an association between exposure to organic dust and longitudinal lung function change.