Researchers focused on Casale Monferrato in Northwest Italy, an area known for its high number of mesothelioma cases linked to the Eternit asbestos-cement plant. Although the plant was closed in 1986, mesothelioma cases continue to crop up. In an effort to determine how often that happens or is likely to happen in the future, researchers studied the cases of 200 mesothelioma patients and 348 healthy people.
They found that the odds ratio (OR) for mesothelioma, a measure of association between an exposure and an outcome, was four to fifteen times higher in asbestos-exposed individuals. The OR increased with increased exposure. Even people who had never been exposed to asbestos on the job at the cement plant had an OR for mesothelioma from 3.8 to 23.3. The research found that just living in a house near a building with “large asbestos cement parts” produced an OR for mesothelioma of 2, high enough to be statistically significant.
“Our results also provide indication of risk associated with common sources of environmental exposure and are highly relevant for the evaluation of residual risk after the cessation of asbestos industrial use,” writes lead study author Daniela Ferrante of the University Piemonte Orientale in Novara.
Previous studies have also shown that asbestos can remain in the environment for decades after an asbestos industry like the Eternit cement plant moves out. The mechanism by which asbestos causes mesothelioma is not fully understood but is believed to involve chronic (sometimes decades-long) irritation and inflammation of lung tissue by inhaled or ingested asbestos fibers.
Ferrante, D, “Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment”, August 11, 2015, Occupational and Environmental Medicine, Epub ahead of print