Italian researchers looked at the geographic distribution of malignant mesothelioma cases and found that they tend to be clustered around cement manufacturing, shipbuilding, and other industrial facilities.
A team lead by Marisa Corfiata analyzed 15,322 incident cases of malignant mesothelioma from the period 1993 to 2008 recorded by the Italian national mesothelioma registry. Subjects were interviewed and asbestos exposure—the only known cause of mesothelioma—was defined for 11,852 of 15,322 cases. Cases were then then mapped and geographic clusters identified for the Northwest, Northeast, Centre, and South & Islands regions of Italy. Finally, case clusters were identified according to one of three asbestos exposure modalities: environmental, familial, and occupational.
According to the researchers, the main sources of mesotheliomas are cement manufacturing plants and shipyards, while several case clusters were also found in the vicinity of asbestos textile facilities.
“The largest [malignant mesothelioma] clusters, per number of cases or municipalities included were found, indeed, where the biggest asbestos cement plants or shipyard facilities were located,” writes Corfiata. “Overall, it should be noted that an asbestos cement industry, an asbestos textile industry or a harbor industrial area inclusive of shipyards partially contribute to exposure of MM cases in about 75% of the clusters identified.”
Diving deeper into the numbers, the researchers note that the high number of mesothelioma cases among women in the largest asbestos-cement industry clusters may be attributable to familial exposure, or so-called “take home” exposure, which occurs when one family member brings home asbestos fibers on their body or clothing and exposes other family members. For the shipyard clusters, mesothelioma is mainly associated with naval construction and/or repair activities.
The researchers also note a number of other industrial asbestos exposure sources, including steel manufacturing plants, metal product manufacturing, oil refineries, chemical facilities, power plants, railway carriage construction and maintenance, the automotive industry, glass industry, and food processing. These are many of the same industries that have historically in the United States produced occupational asbestos exposure.
But unlike the United States, Italy has enacted a national asbestos ban. The study points out that Italian asbestos consumption peaked later in Italy than in the U.S., and, given the 35-40 year latency period of mesothelioma, “a high number of cases is still expected in Italy in the next few decades.”
Mesothelioma incidence is thought to have already peaked in the United States, but as long as the use of asbestos products remains legal in this country, the carcinogenic mineral fiber continues to pose a threat to public health. Each year in the U.S. approximately 3,000 people are diagnosed with mesothelioma, while 10,000 total death are attributed to asbestos.
You can read the full text of the Italian report “Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry” at BMC Cancer.