Asbestos is a mineral that exists in the environment. It is made of very fine fibres that are strong. Asbestos resists destruction from heat and chemicals and is therefore used in many commercial products as insulators, in the construction of buildings and as friction-resistant products.
Asbestos exposure
Tiny fibres of asbestos suspended in the air are inhaled. They are deposited in the lungs where they cause irritation and chronic inflammation. People living close to asbestos factories or mines are at higher risk of inhalation of asbestos fibres. Renovation of old buildings where asbestos was used for insulation in the ceiling and floor tiles increase exposure.
Health effects of asbestos
Asbestos fibres that are inhaled during respiration settle in the respiratory passage and lungs. Some of these are coughed out and expectorated or swallowed. The remaining fibres in the lungs cause fibrosis or scarring of the lungs. This results in irreversible damage to the lungs and impairs lung function. The genesis of these diseases may take 3 to 5 decades or longer.
Asbestos-related diseases are as follows:
Asbestosis
Lung cancer
Mesothelioma or cancer of the outer lining of lungs
Asbestosis
After years of exposure, a person develops difficulty in breathing that is gradually progressive. Spells of infection result in fever and increase lung damage. Non-productive cough seen in these people becomes productive in the presence of infection. The fingers become deformed and look like drum-sticks. In long-standing disease, there is swelling of legs and bluish discolouration of lips due to lack of oxygenation of blood. The breathing difficulty is easily aggravated on exertion like climbing stairs or brisk walking. This also reflects the degree of lung scarring. A chest x-ray shows evidence of lung scarring and indicates the severity of lung damage. Lung function tests and CT scanning is also done for the diagnosis of this condition. The diagnosis is confirmed by taking a piece of lung and examining it under a microscope. It shows fibrosis or scar tissue and asbestos bodies. The treatment includes antibiotics for infection, immunization against influenza and Pneumococcal pneumonia. Smoking should be prevented completely as it aggravates the symptoms. Oxygen therapy is required when a person is unable to maintain normal blood oxygen levels as seen during an episode of infection. Once this condition is detected, further exposure to asbestos should be prevented.
Cancer
Asbestos is associated with cancer of the lung and pleura (mesothelioma). About half of the cases of occupational lung cancer are related to asbestos exposure as reported by WHO (World health organization). Smoking in association with asbestos exposure multiplies the risk of lung cancer as both are risk factors for this condition. Though asbestos lung cancer and mesothelioma takes years to develop, it spreads very rapidly to other organs. There are two types of asbestos-related lung cancer, called small cell lung cancer and non-small cell lung cancer. Non-small cell lung cancer occurs more commonly and progresses slowly in comparison to small cell variety. It is seen in about 80% of such cases. The small cell variety is seen in the remaining 20% cases and is more rapid growth. It is also more difficult to treat people who develop small cell lung cancer. About 5% of these patients live longer than 5 years whereas this figure is 17% in people with non-small cell lung cancer. Therefore the prognosis of non-small cell cancer is three times better than the small cell lung cancer.
Ingestion of asbestos is related to cancer of the digestive tract and peritoneum. Other cancers related to asbestos exposure include cancer of the larynx, breast, prostate, gallbladder, ovary and kidneys. Lymphoma and leukaemia are also related to asbestos.
Asbestos-related damage in the body is a slow process and is irreversible. Prevention of exposure is the best way to prevent the occurrence of this occupational disease.
