Mesothelioma epidemiology

Mesothelioma on

Friday, 3 April 2015

• Incident

Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. The incidence rate is approximately one per 1,000,000. The highest incidence is found in Great Britain, Australia and Belgium: 30 per 1,000,000 per year. For comparison, populations with high levels of smoking can have a lung cancer incidence of over 1,000 per 1,000,000. The incidence of malignant mesothelioma currently ranges from about 7 40 per 1,000,000 in Western countries, depending on the amount of asbestos exposure that population for decades. It is estimated that the incidence may have peaked at 15 per 1,000,000 in the United States in 2004. The incident is expected to continue to increase in other parts of the world. Mesothelioma occurs more often in men than in women and risk increases with age, but this disease can appear in either men or women at any age. About a fifth one-third of all peritoneal mesotheliomas.

Between 1940 and 1979, approximately 27.5 million people occupationally exposed to asbestos in the United States. Between 1973 and 1984, there was a threefold increase in the diagnosis of pleural mesothelioma in Caucasian male. From 1980 until the late 1990s, the death rate from mesothelioma in the USA increased from 2,000 per year to 3,000, with men four times more likely than women to obtain. This figure may not be accurate, because it may be that many cases of mesothelioma are misdiagnosed as adenocarcinoma of the lung, which is difficult to differentiate from mesothelioma.

• Risk factor

Working with asbestos is the major risk factor for mesothelioma. The history of asbestos exposure exists in almost all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos. In rare cases, mesothelioma has also been associated with irradiation, intrapleural thorium dioxide (Thorotrast), and inhalation of other fibrous silicates, such as erionite.

Asbestos is the name of a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. Asbestos has been widely used in many industrial products, including cement, brake linings, gaskets, tile, flooring products, textiles, and insulation. If tiny asbestos particles float in the air, especially during the manufacturing process, they can be inhaled or swallowed, and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous lung disease, chronic) and other cancers, such as throat and kidneys.

The combination of smoking and asbestos exposure significantly increases a person's risk of developing cancer Airways (lung cancer, bronchial carcinoma). Kent brand of cigarettes used asbestos in the filter for the first few years of production in the 1950s and some cases of mesothelioma have resulted. Modern Smoking does not seem to increase the risk of mesothelioma.

Some studies suggest that simian virus 40 (SV40) may act as a cofactor in the development of mesothelioma.

• Exposure

Asbestos was known in ancient times, but was not mined and widely used commercially until the late 1800s. Its use greatly increased during World War II. Since the early 1940s, millions of US workers who have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not known by the public. However, an increased risk of developing mesothelioma was later found among shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other merchants.

Today, the US Safety and Health Administration (OSHA) sets limits for acceptable levels of asbestos exposure in the workplace, and created guidelines for engineering controls and respirators, protective clothing, exposure monitoring, hygiene facilities and practices, warning signs, labeling, books, and medical exams. In contrast, the British government health and safety executive (K3) states formally that any threshold for mesothelioma must be at a very low level and many agree that if any such limits exist at all, then it is not at this time can be measured. For practical purposes, therefore, the K3 does not assume that there are no such limits. People who work with asbestos wear personal protective equipment to reduce the risk of exposure.

• Environmental exposure

Incidence of mesothelioma had been found to be higher in populations living near naturally asbestos. For example, in Cappadocia, Turkey, mesothelioma causes 50% of all deaths in three small villages-Tuzköy, Karain and Sarıhıdır. Initially, this was attributed to erionite, a zeolite mineral with similar properties to asbestos, however, recently, detailed epidemiological investigation showed that erionite causes mesothelioma mostly families with a genetic predisposition.

• The Work

Exposure to asbestos fibers has been recognized as a health hazard since the early 1900s. Several epidemiological studies have associated exposure to asbestos with the development of lesions such as asbestos bodies in the sputum, pleural plaques, diffuse pleural thickening, asbestosis, carcinoma of the lung and larynx, gastrointestinal tumors, and spread the pleural and peritoneal mesothelioma.

Documented presence of asbestos fibers in water supplies and food products has fostered concerns about the possible long-term effects, however, are not known to the general population exposure to these fibers. Although many authorities consider brief or transient exposure to asbestos fibers world and a possible risk factor, some epidemiological claims that there is no risk threshold. Mesothelioma cases have been found in people whose only exposure was breathing the air through the ventilation system. Other cases had very minimal (3 months or less) direct exposure.

Commercial asbestos mining at Wittenoom, Western Australia, occurred between 1945 to 1966. A cohort study of miners working in the mine reported that while no deaths occurred within the first 10 years after crocidolite, 85 deaths related to mesothelioma had occurred prior to 1985. In 1994, 539 reported deaths due to mesothelioma has been reported in Western Australia.

• Secondary Paraoccupational exposure

Family members and others living with asbestos workers have an increased risk of developing mesothelioma, and possibly other asbestos related diseases. This risk may be the result of exposure to asbestos dust brought home on the clothing and hair of asbestos workers. To reduce the chance of exposing family members to asbestos fibers, asbestos workers are usually required to shower and change their clothing before leaving the workplace.

• Asbestos in buildings

Many building materials used in domestic public and local before banning of asbestos may contain asbestos. People who perform renovations or DIY activities may expose themselves to asbestos dust. In the UK, the use of Chrysotile asbestos was banned at the end of 1999. Brown and blue asbestos was banned in the UK around 1985. Buildings built or renovated prior to these dates may contain asbestos materials.

Labels: Mesothelioma, Mesothelioma Epidemiology

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