What causes asbestosis?
Asbestosis is caused by long-term inhalation of asbestos fibers. People with occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. There is an increased risk of lung cancer and mesothelioma associated with asbestosis. The risk is related to the total dose of asbestos received and the duration of asbestos exposure. Exposure to the crocidolite form of asbestos is the form most associated with mesothelioma among the four forms of asbestos. Occupational exposure is the most common cause of asbestosis, but the condition also
strikes people who inhale asbestos fiber or who are exposed to waste products from plants near their homes. Family members can develop the disease as a result of inhaling particles of asbestos dust that cling to workers' clothes.
Normally, microorganisms, dust and other foreign particles in the air you breathe are filtered out by being trapped in your nose hairs or being expelled when you cough. Asbestos particles (called amphiboles) are long, extremely thin, microscopic glass-like fibers that are not filtered by the nose or the bronchi because they are so thin and light. Asbestosis development starts when a person inhales an amphibole. This particle travels deep into the lungs to one of the 300 million gas exchanging structures called an alveolus. Each alveolus has many cleaning cells called macrophages that eat up any particles that made it down to the alveoli. Alveoli have very thin, elastic walls that allow an exchange of gases vital to your health - oxygen flows from the alveoli into your bloodstream to nourish your body, and carbon dioxide waste flows from your bloodstream into the alveoli and on into your bronchi to be expelled.
Asbestos fibers can easily flake off and are small enough to be inhaled deep into the lungs. When they are inhaled into the lungs, the lungs’ defense cells try to destroy the asbestos fibers, but the body's defense mechanisms cannot break down asbestos. The result is that the asbestos fibers remain in the lungs and cause inflammation and scarring. This inflammation and scarring continues for decades, and over time prevents oxygen and carbon dioxide from traveling between the tiny air sacs of the lungs and into the blood stream. Eventually, breathing becomes much less efficient and severe complications arise.
Asbestos fibers are difficult to destroy, even for macrophages. When a macrophage attempts to ingest an asbestos fiber, it often fails because the fiber is too long. In the process, however, the macrophage leaks out substances that were supposed to destroy the foreign body but that can also harm the alveoli. This causes the alveoli to become inflamed and eventually scar, a process referred to as fibrosis. If many fibers are inhaled over a long period of time, the cumulative scarring of alveoli reduces their ability to exchange oxygen and carbon dioxide. The result is that your lung capacity diminishes, oxygen exchange is diminished, and you feel increasingly short of breath.