Asbestos and Lung Diseases: Introduction and Epidemiology

Abstract

Over the last 2 centuries, there has been a growing awareness of occupationally related lung disease resulting from exposure to inorganic particulates that cause chronic and disabling fibrotic lung disease that can be fatal. Fibrotic lung disease, because of dust exposure, is referred to as pneumoconiosis. Asbestos refers to a group of naturally occurring minerals that has been extensively used in diverse industries as the minerals are known for their high tensile strength and flexibility and exhibit high thermal and chemical degradation as well as electrical resistance. 1 Asbestos fibers are either straight or curved and are referred to as amphiboles or serpentine type. Chrysotile, or often called white asbestos, is a serpentine form and widely used in USA in the past. Amphiboles may be more carcinogenic than the serpentine type. In the late 19th century, the industrial import of asbestos to England from Canada grew, and workers’ exposure to asbestos increased, resulting in a gradual increase in asbestos-related morbidity and mortality. Reports of asbestos-related illness and fatal cases started to appear in the lay press in England (1898, 1906), France (1906), and Italy (1908). Many of these reports involved exposure to Canadian chrysotile fiber. From early (1900s) reports of pulmonary fibrosis, referred to as asbestosis, resulting in significant morbidity and mortality, emerged the scientific literature in England, USA, and Europe. Despite the strong evidence regarding the adverse health effects of asbestos fibers, industries had no restriction or regulations in regard to the use of asbestos. 1-3 The studies from Canada were not supportive of asbestos-related lung diseases in the first half of 20th century and they continued to use the fiber. In 1931, regulation regarding asbestos use was established in Britain. Only in 1955, Canada acknowledged the occurrence of asbestosis in the miners and mill workers. 3 The carcinogenicity of asbestos was initially noted in an animal study using mice but the results were not widely accepted. Based on the Saranac research Vorwald reported an increased association of malig