Incidence of Mesothelioma

Mesothelioma incidence specifies the number of new cases of mesothelioma diagnosed over a certain period of time. Incidence can be identified for various populations. Statistics can be broken down by age, gender, and geographic location. In the United States, the incidence of mesothelioma is thought to have reached a peak and is now tapering off. This is largely due to regulations on the asbestos use. In most other countries around the world, incidence of mesothelioma continues to rise.

Incidence is an important puzzle piece in the epidemiology of a disease, as is etiology (description of causes). Knowing subsets of the population at a higher risk for mesothelioma, as well as what is causing the disease, helps policy makers, advocates, and researchers take appropriate steps in prevention and treatment.

Mesothelioma Incidence by Age and Gender

Researchers are able to form a picture of who is at risk and why by looking at incidence for certain diseases in specific populations. Understanding incidence also helps pinpoint causes for a disease. According to the National Cancer Institute, the incidence of mesothelioma in the United States is consistently higher in men than women. Incidence peaked for both in the 1990s. Since then, there has been a considerable downward trend. In 2009, the mesothelioma rate in men was about 1.8 per 100,000. In women, it was about 0.9.

The incidence of mesothelioma is higher for older Americans. Between 2008 and 2010, the incidence for men over 85 was 20.2. For men between 55 and 64 it was only 2.1. Men between the ages of 75 and 84 showed an incidence of 6.8, and for those between 75 and 84 it was 17.2. For women, the incidence also rises with age, from 0.6 for ages 55 to 64 to 3.1 for women over 85.

The difference in incidence between men and women is typically explained by the major risk factor for mesothelioma. More men than women have worked in industries that put them at risk asbestos exposure. By age, the incidence grows as the population gets older because mesothelioma has a long latency period. It can take decades to develop symptoms and receive a diagnosis.

Incidence of Mesothelioma by Job

Occupation is another major factor in the incidence of mesothelioma. The major cause of mesothelioma is asbestos exposure. Therefore, industries that commonly used asbestos have a higher risk of developing mesothelioma. While the link between asbestos and mesothelioma is now common knowledge, there was time the connection was not so clear. High incidence rates in industries with asbestos helped clarify the role it plays in this disease.

The Centers for Disease Control and Prevention (CDC) listed the occupations with the highest incidences of mesothelioma. These occupations are construction workers, plumbers, pipefitters, steamfitters, janitors, cleaners, managers, and workers in chemical industries. In the United Kingdom, a country with higher rates of mesothelioma, occupations with the highest incidences include carpenters, joiners, construction workers, electricians, plumbers, metal workers, and heating and ventilating workers.

Incidence in Shipyards

Construction workers, pipefitters, steamfitters, plumbers, electricians, and others have higher risks of developing mesothelioma, particularly in one industry: ship building and repair. An epidemiological study of Virginia’s coastal shipyards found the incidence of mesothelioma was four times higher for shipbuilders than the national average.

Understanding incidence in specific industries, occupations, and regions, helps pinpoint exactly where people are at risk. By discovering the high incidence of mesothelioma in Virginia shipyard workers, researchers provided information that led to safer working conditions in the industry.

Incidence by Geography

Epidemiological studies of mesothelioma have discovered certain areas are more affected than the rest of the country. New Jersey, for instance, has one of the highest incidences of mesothelioma. The Johns Manville Corporation is most likely responsible. This company operated an asbestos plant in Manville, New Jersey for decades. The incidence of mesothelioma among Manville workers was 25 times higher than the national average.

Other areas with higher incidences of mesothelioma include areas of Washington, Louisiana, Connecticut, New Mexico, California, Utah, and Detroit, Michigan. Some of these are explained by the presence of asbestos mines, shipyards, or other industries that used asbestos. New York City is expected to see an increase in the incidence of mesothelioma in the coming decades as people exposed to dust from the World Trade Center attacks develop the disease.

Worldwide Incidence

For most of the United States, the incidence of mesothelioma has reached a peak and begun to decline. This decrease is due to increased regulations on asbestos use and workplace safety. Other countries are still experiencing an upward trend, including developed nations like the United Kingdom and Australia. The overall incidence is still rising around the world.

According to the World Health Organization, between 1994 and 2008 the worldwide mortality rate for mesothelioma was 4.9 deaths per million people. During that same time period, the average age of someone who died from mesothelioma was 70. Also, the ratio of men to women with the disease was 3.6 to one. These worldwide trends mirror those seen in the United States.

Understanding the incidence of a disease like mesothelioma is important for understanding the disease itself. Incidence helps explain causes of the disease. It also helps those at risk by shedding light on risk factors, such as age, gender, industry, occupation, and geographical location.