Chrysotile is one of six fibrous minerals that are classified as asbestos. Known as white asbestos, chrysotile is the most common type, accounting for about 95 of the asbestos used in industry. Chrysotile fibers are strong and can be made into thread and woven into cloth for flame retardant blankets and insulators. Like all types of asbestos, it is resistant to heat and flame.
Although chrysotile was heavily used in textile workshops in Southeast China, no clear link had been drawn between workshop use of chrysotile and development of mesothelioma until now. In the new study, researchers from both China and Japan focused on the cases of 28 mesothelioma patients at China’s Yuyao People’s Hospital.
The 28 study subjects represented all confirmed mesothelioma patients diagnosed at the hospital from 2003 to 2010. All of the patients were women and most were from one of two small towns with multiple small asbestos textile workshops. Not surprisingly, all of the women had a history of exposure to chrysotile either in their home or in a textile factory.
What was surprising, however, was the fact that, although pleural mesothelioma is the most common variety of mesothelioma worldwide, more than two thirds of the patients in the Chinese study had peritoneal mesothelioma, a figure which the researchers refer to as an “over-representation.”
All types of asbestos have been shown to cause mesothelioma, a rare and intractable cancer that starts on the membranes around organs. While most mesothelioma occurs on the pleural membrane which surrounds the lungs, about a fifth of cases occur on the peritoneum which lines the abdomen. In the US, peritoneal mesothelioma accounts for fewer than 500 of the 2,500 mesothelioma cases each year. There is no explanation as to why peritoneal mesothelioma was more common than pleural mesothelioma in the Chinese textile workers.
The new study is published in the American Journal of Industrial Medicine.
Gao, Zhibin et al, “Asbestos textile production inked to malignant peritoneal and pleual mesothelioma in women: Analysis of 28 cases in Southeast China”, July 6, 2015, American Journal of Industrial Medicine, Epub ahead of print