The Impact of Occupational Exposures on the Risk of Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis.

Rationale Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic pulmonary disorder of unknown etiology, characterized by a usual interstitial pneumonia (UIP) pattern. Previous meta-analyses have reported associations between occupational exposures and IPF, but higher-quality studies have been published in recent years, doubling the number of studied patients. Objective To provide a contemporary and comprehensive assessment of the relationship between occupational exposures and IPF. Study Design and Methods We searched Pubmed, Embase, and Web of Science through July 2023 to identify all publications on occupational exposure and IPF. We conducted a meta-analysis of the occupational burden, odds ratio (OR), and population attributable fraction (PAF) of exposures. Five exposure categories were analyzed: VGDF (vapors, gas, dust, and fumes), metal dust, wood dust, silica dust, and agricultural dust. A comprehensive bias assessment was performed. The study protocol was registered to the International Prospective Register of Systematic Reviews (ID: CRD42021267808). Results Our search identified 23,942 publications. Sixteen publications contained relative risks needed to calculate pooled ORs and PAFs, and 12 additional publications reported an occupational burden within a case series. The proportion of cases with occupational exposures to VGDF was 44% [95% confidence interval (CI), 36-53], with a range of 8-17% within more specific exposure categories. The pooled OR was elevated for VGDF at 1.8 (CI, 1.3-2.4), with a pooled PAF of 21% (CI, 15-28). The OR and PAF were respectively found to be 1.6 and 7% (metal dust), 1.6 and 3% (wood dust), 1.8 and 14% (agricultural dust), and 1.8 and 4% (silica dust). The pooled OR and PAF within specific exposure categories ranged from 1.6-1.8 and 4-14%, respectively. We identified some publication bias, though it was not sufficient to diminish the association between occupational exposures and IPF based on sensitivity analysis and bias assessment. Conclusions Our findings indicate that 21% (or approximately 1 in 5) IPF cases could be prevented by removal of occupational exposure (alongside a pooled OR of 1.8). Additionally, 44% of patients with IPF report occupational exposure to VGDF. This meta-analysis suggests that a considerable number of cases of IPF are attributable to inhaled occupational exposures and warrant increased consideration in the clinical care of patients and future prevention efforts. Clinical Trials Registration International Prospective Register of Systematic Reviews (ID: CRD42021267808).