Environmental Exposure to Respirable Particles and Estimated Risk of Sarcoidosis: A Systematic Review and Meta-Analysis

Introduction Sarcoidosis is an inflammatory disease of unknown etiology that affects multiple organs in the body. In most cases, the affected organ is the lung. Sarcoidosis risk factors include environmental exposures, genetic predisposition, and immunological factors. The main objective of this review was to assess whether exposure to respirable particles is associated with increased risk of sarcoidosis. Methods A comprehensive search was conducted in scientific databases. Additional search of grey literature as well as handsearching of relevant records was performed. The search was restricted to studies published between January 1998 to October 2019. Meta-analysis was performed for studies that provided quantitative data. Results After applying inclusion/exclusion criteria, nine articles were included in the systematic review and four in the meta-analysis. Quantitative analysis suggested that people exposed to respirable particles were approximately three times more likely to develop sarcoidosis compared to people who are unexposed. Discussion and conclusion This study collected and aggregated available evidence that assessed exposure to respirable particles and risk of developing sarcoidosis. Evidence of increased association between exposure to respirable particles and sarcoidosis was strongly suggested based on our qualitative review. More rigorous epidemiologic exposure studies are needed to generate data that would accurately determine the risk and causal pathways through which exposure to respirable particles could lead to the development of sarcoidosis.