What is Mesothelioma? Mesothelioma and its connection to environmental asbestos exposure has typically been associated with white males over the age of 60. However, there has been a shift in age and gender as the trend for worldwide use of asbestos has declined and more industrialized nations continue to ban the use of the toxic mineral.
Malignant mesothelioma is a rare, asbestos-related cancer that develops on the thin protective tissues that cover the lungs and abdomen. Doctors diagnose an estimated 3,000 cases of mesothelioma annually in the United States. Most of those cases are traced to job-related exposures to asbestos such as working at industrial or residential construction, as factory workers, shipyard workers, or auto repair mechanics, to name a few.
Asbestos may cause health issues when asbestos-containing materials are disturbed and asbestos fibers are released into the air. When these microscopic fibers are inhaled, the body struggles to expel them. Over decades, the trapped fibers trigger biological changes than may cause inflammation, scarring, and genetic damage that may lead to cancer.
Symptoms of mesothelioma include fatigue, slight pain around the tumor in early stages, shortness of breath, chronic pain near the tumor in later stages, weight loss, fluid buildup, or bowel obstruction.
The lengthy gap between asbestos exposure and diagnosis is called the latency period. It can be between 20 to 50 years. Asbestos fibers usually become trapped in the lining of the lungs (pleura). The fibers can also collect in the lining of the abdominal cavity (peritoneum) or heart (pericardium). When asbestos fibers cause biological damage, that is when decades-long latency period may be ripe for the development of malignant mesothelioma.
Studying Environmental Risk of Mesothelioma and Asbestos
A study analyzing environmental risk of mesothelioma and asbestos in the U.S. and its effect on women and young people was designed and performed by University of New Caledonia epidemiologist Francine Baumann.
“In countries where asbestos is no longer used by the industry, and where there are other fibrous minerals present in the natural environment, I think that the proportion of environmental causes of exposure is very likely increasing, and that the proportion of female and young mesothelioma cases is also very likely to rise,” Baumann told Asbestos.com.
There have been reported cases of male and female school teachers who developed mesothelioma. They were found to have worked for numerous years in school buildings containing asbestos. Some interior decorators were exposed to asbestos from spray-on asbestos materials. Some bakers have developed mesothelioma due to asbestos in and around ovens.
The Journal of Toxicology and Environmental Health recently published Baumann’s study results. Environmental asbestos exposure normally occurs from natural deposits of fibrous minerals found in specific geographic areas. Over time, these deposits may become disturbed through road construction commercial development, or natural erosion. These factors, added to dry conditions and high winds, send toxic asbestos fibers in the air, which may become deadly if inhaled.
“The [U.S. Geological Survey] recently updated their maps of asbestos and other fibrous deposits, showing that the soil of California and other western states contain large deposits of these minerals,” Baumann said. Mexico, Greece, Turkey, Italy, Australia, South Africa, and Corsica, are other countries at high risk for environmental asbestos exposure.
“Studying an environmental exposure is very challenging, because people don’t know that if they have been exposed, when they have been exposed, and to what they have been exposed,” Baumann said. “Environmental epidemiology is developing its own methods, which are often based on ecological studies, using small geographical areas as units instead of individuals.”
Since environmental epidemiology has to focus on geographic areas instead of individuals, Baumann analyzed all mesothelioma deaths reported to the Centers for Disease Control and Prevention (CDC) during 1999 to 2010.
Men born in the 1920s significantly outweighed reported deaths and younger deaths but declined with time. This suggests a decline in occupational exposure. The incidence and mortality rates among women increased over time, suggesting an increase proportion of environmental cases.
A 2015 report from Baumann and researchers at the University of Hawaii Cancer Center linked environmental asbestos exposure to a growing number of mesothelioma cases among women and younger residents of southern Nevada counties, including Las Vegas.
Baumann analyzed the distribution of mesothelioma by sex and by age group in the counties by examining governmental statistics, as well as soil, rock, and air samples.
“I discovered that, in southern Nevada, the percentage of female and young people among mesothelioma cases was significantly elevated, compared to other Nevada regions and to the U.S., in general,” Baumann said. “This indicated the presence of environmental exposure to carcinogenic fibers.”
Southern Nevada residents under 55 accounted for almost double the percentage of mesothelioma deaths in that age group compared to the national average. The male to female ratio was significantly closer in the area compared to the rest of Nevada and the U.S. This news was especially alarming for residents of Las Vegas, a worldwide resort destination depending on tourism.