Incidence is the occurrence, rate, or frequency of a disease. The incidence of mesothelioma varies by region, occupation, and due to biological factors.
Why is Incidence Important?
Studying the incidence of mesothelioma throughout the world can lead to better understanding of the disease. Researchers have discovered common traits among those exposed to asbestos and have even created the basis for genetic research.
Mesothelioma Incidence Factors
There are approximately 3,000 new cases of mesothelioma every year in the United States. Some regions in the country have a higher incidence of mesothelioma.
Age and Gender
Age and gender are two of the most consistent factors in the incidence of mesothelioma across the globe. Male patients over the age of 65 make up an overwhelming majority.
Occupational asbestos exposure is the most common cause of mesothelioma due to the mineral’s industrial applications. This helps account for why incidence among men is so common.
Trends in Mesothelioma
The study of mesothelioma incidence is about observing trends in the occurrences of the disease. In medicine, this field of study is known as epidemiology. People in this field act as detectives, investigating the causes of deadly diseases.
Epidemiologists collect information based on demographics, symptoms and exposure history to predict the future incidence of mesothelioma. The ultimate goal of epidemiologists is to prevent the outbreak of future cases of mesothelioma by studying patterns and distribution of disease. Learn more about these patterns and recent trends in our free Mesothelioma Guide.
Incidence By Region
There are currently around 3,000 cases of mesothelioma diagnosed each year in the United States. Other countries have a higher incidence and are likely to increase over time. The highest rates of mesothelioma are seen in Australia and Great Britain, where the number of new cases there are similar in number to those found in the US each year, despite their having a combined population equal to less than one-third of the population of the US.
Regions with a high presence of industries that use large amounts of asbestos, such as shipbuilding, often have a higher incidence of mesothelioma. Some countries with high rates of asbestos use do not have a correspondingly high incidence of mesothelioma. This implies non-industry-related factors that may contribute to mesothelioma, such as genetic predispositions, viruses or impairments in the immune system.
There are even certain regions within the United States itself that have a higher incidence of mesothelioma. Similar to the global presence of mesothelioma, this is related to regions with asbestos-based industries. Some areas with a higher than average incidence are Minnesota, Utah and California.
Incidence By Gender
There is a higher incidence of mesothelioma among men than women. While there could be genetic factors that contribute to this, no studies have shown a link. It is widely accepted that there are more men with mesothelioma because of the nature of their asbestos exposure.
Occupational exposure is responsible for more cases of mesothelioma than secondhand or environmental exposure. Men, who have traditionally worked in industrial trades, are exposed to more asbestos than women. Exposure among women is usually due to secondhand exposure from their spouse.
Incidence By Race
Mesothelioma predominantly affects Caucasians. Diagnoses in patients of other races is exceedingly rare.
Incidence By Age
The incidence of mesothelioma is likely to increase as people are living longer than they were 10-20 years ago. The disease is most common in people over the age of 65, mainly because of the latency period associated with mesothelioma—it takes anywhere from 20-50 years for tumors to develop. Furthermore, a recent study found that for people exposed to asbestos, the risk of developing mesothelioma never goes away and increases as they get older.
Researchers can study demographic information on the incidence of mesothelioma to help determine genetic predispositions for the disease and to understand more about how asbestos causes it.
Erionite in Cappadocia
There are several small villages throughout Cappadocia, Turkey that have relied on a naturally occurring mineral called erionite to build their homes. The mineral is structurally similar to asbestos and has recently been found to cause mesothelioma. The prevalence of this mineral in Cappadocia is responsible for the overwhelming cases of mesothelioma in the region.
Mesothelioma was responsible for over 50 percent of all deaths in three villages in Cappadocia. Nearly a quarter of all of Turkey’s new cases of mesothelioma come from the region.
Epidemiological research has proven a fruitful venture in the case of Cappadocia. Mesothelioma specialist Dr. Michele Carbone found a common factor among those developing mesothelioma in the region—a genetic mutation in the BAP1 gene. This was discovered by observing a higher incidence of mesothelioma among some families. The hunch that there could be a genetic relationship to the disease was validated.
Libby Epidemiology Research Project (LERP)
Epidemiological investigators didn’t have to work hard to find the origins of mesothelioma cases that were rampant in Libby, Montana. The small mining town was based around a W.R. Grace plant, which mined vermiculite contaminated with asbestos.
A large proportion of Libby’s population worked at the plant and were exposed to asbestos and bringing those fibers home with them on their clothes. Even baseball diamonds throughout the town were contaminated because W.R. Grace donated its waste dirt from the mine (loaded with asbestos) to supply them.
The incidence of mesothelioma in Libby is incomparable to other areas of the United States. Families that have lived in Libby their whole lives were subjected multiple cases of the disease among their relatives.
Mesothelioma is very rare, but it’s even more rare for multiple cases to occur in the same family. This gave researchers the motivation to form the Libby Epidemiology Research Project. LERP’s purpose is to collect data and study the cases of mesothelioma in Libby. This may lead to conclusions about the specific toxicity of Libby asbestos, which was exported throughout the country, as well as any potential genetic links to mesothelioma.