The environmental epidemiology of idiopathic interstitial lung disease including sarcoidosis

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders ch aracterized by inflammation of the pulmonary interstitium and related struc tures. Many of these disorders, such as asbestosis, silicosis, coal workers ) pneumoconiosis, and hypersensitivity pneumonitis, have known environmenta l causes. However, among patients with ILDs seen by clinicians in the gener al population, only about 15% have an identifiable cause. In this article, we review the biological, clinical, and epidemiological evidence that sugge sts that most idiopathic ILDs are initiated by environmental exposures, The clinicopathological classifications of ILDs are reviewed in association wi th known causes, and a review of the current literature linking idiopathic pulmonary fibrosis and sarcoidosis to environmental etiologies is presented .