Occupational Exposures associated with Pulmonary Sarcoidosis: A Systematic Review and Meta-analysis

Abstract

Background: The aetio-pathophysiology of sarcoidosis is not fully defined – current hypotheses centre on complex genetic-immune-environmental interactions in individuals triggering a granulomatous process.

Aim: Define and describe the inhalable/ respirable occupational exposures associated with a diagnosis of pulmonary sarcoidosis (PS).

Methods: A systematic review (PROSPERO ID:CRD42020199054) of the odds of pulmonary sarcoidosis with various occupational exposures. 8830 studies were assessed against eligibility criteria by 2 independent reviewers. Proportions or odds of identified and specified occupational exposures in PS were extracted. Meta-analysis of odds ratios (OR; random effects model [pooled log estimate of OR; DerSimonian Laird]) using STATA v16 are reported.

Results: N=79 occupational exposures have been associated with PS in literature across all study designs - silica (n=34), iron (n=13) and aluminium (n=12) exposure are most frequently reported. N=13 occupational exposures were reported in ≥2 observational studies. Insecticide, pesticide & herbicide exposure (OR 1.42 [95% CI 1.09 – 1.85], I² 14.3%) and occupational mold or mildew exposure (OR 1.52 [95% CI 1.21 – 1.91], I² 0%) had increased odds of PS. Trends in increased odds between occupational silica (OR 1.15 [95% CI 0.80 – 1.66], I² 86.4%), aluminium (OR 1.89 [95% CI 0.72 – 4.95], I² 90.5%) and nickel (OR 1.18 [95% CI 0.65 – 2.14], I² 0%) were seen.

Conclusion: Occupational exposure to insecticides, pesticides & herbicides, and mold & mildew increase the odds of a diagnosis of pulmonary sarcoidosis. Equipoise persists concerning the role of silica and metal dust such as aluminium and nickel in pulmonary sarcoidosis.