August 18, 2011
The use of asbestos building materials in developing countries results in millions of preventable cancer cases, a University of Wisconsin School of Medicine and Public Health epidemiologist reports in the coming issue of Annals of Epidemiology.
Dr. Marty S. Kanarek, professor of population health sciences and a faculty member in the Nelson Institute for Environmental Studies, says his review of health studies from around the world suggests that an epidemic of asbestos-caused mesothelioma is brewing in the developing world. The United States and Europe banned the use of such materials long ago.
"My conclusion and the conclusion of many other environmental health scientists is that all asbestos should be banned worldwide," says Kanarek, who has been studying the health effects of asbestos for about 40 years. "We could prevent a million or more cases of cancer. The evidence is very clear."
Kanarek, who has taught and done research on various topics in environmental health and epidemiology at UW-Madison since 1978, first looked at health problems caused by asbestos in the drinking water of the San Francisco Bay Area in the early 1970s.
Kanarek's review looked at cases of mesothelioma, a rare cancer of the lining of the lungs and abdominal cavity that can occur more than 50 years after exposure to asbestos. Most victims worked around asbestos, a fire-retarding mineral that was used in brake linings, insulation and building materials.
"It is a terrible cancer, quickly fatal, and practically impossible to treat because it is so diffuse throughout the body," he says.
Asbestos exposure also causes other cancers of the lung, larynx, and gastrointestinal tract and a chronic lung inflammation known as asbestosis. Worldwide it is the cause of about 10 million deaths; in the United States, it is blamed for 131,200 cancer deaths between 1985 and 2009.
Kanarek says the link between asbestos and fatal health problems has been known for a century. But, he says the asbestos industry obscured the issue by claiming that the health problems were only caused by a rarely used type of asbestos, and not by chrysotile or "white" asbestos, which accounts for about 95 percent of world production and use. Countries such as Canada continue to mine asbestos, but ship it overseas because its use is banned at home.
Kanarek reviewed dozens of studies of mesothelioma cases, ranging from those among miners in Zimbabwe, brake workers in the United States, cement pipe factory workers in Egypt, and many others. He concludes that despite industry protestations, chrysotile asbestos is associated with mesothelioma cases around the world.
"Because asbestos has not yet been banned in many countries, there are projections of an increasing mesothelioma epidemic worldwide," Kanarek says. "Today there are many safer, cheaper substitute materials available, so the time is long past for a worldwide asbestos ban."