Work-related interstitial lung disease: what is the true burden?

Interstitial lung diseases (ILDs) include a large variety of fibrotic lung conditions caused by genetic and environ-mental factors. Occupational exposures might also play a significant role, but the real health burden is currently unknown. Here, we aim to evaluate the role of work-related exposures in ILDs, focussing on idiopathic pulmonary fibrosis (IPF) and hypersensitivity pneumonitis (HP). We performed a focused review of the literature on work-related HP and IPF over the past 5 years. Using a meta-analytic approach, we quantified the occupational burden of IPF and HP, and estimated that occupational exposures to metal, silica and environmental tobacco smoke increased IPF risk with a pooled odds ratio of 1.7 (95% CI 1.42-2.03). The proportion of HP cases related to workplace exposure was 17% (95% CI 7-28). Our review supports the hypothesis that occupational exposures are a significant risk factor in the aetiopathogenesis of IPF and HP. We recommend that further research be performed to identify the underlying occupational factors and the maximum permitted exposure to reduce the associated IPF and HP burden.