An Australian study published in the journal Chest indicates that age and gender have bearing on how likely asbestos exposure is to result in mesothelioma. Researcher Alison Reid studied residents of the town of Wittenoom, Western Australia. Like Libby, Montana, Wittenoom was the home of a major asbestos mining and milling operation. Wittenoom’s asbestos operations, which began in 1943, were closed down in 1966. Because of the lengthy latency period of asbestos-related diseases and the ability of asbestos fibers to float in the air for weeks and months, however, the legacy of asbestos disease remains. The type of asbestos mined at Wittenoom was so-called “blue asbestos,” technically called “crocidolite.” This form of asbestos is particularly deadly, consisting of what are known as “amphibole” fibers that appear and behave as microscopic spears or needles.
Once breathed into the lungs, amphiboles burrow through lung tissue from the inside, working their way out to the lung surface and the pleural lining. Medical researchers believe these fibers cause mutations in cellular DNA, causing them to become malignant. As one might expect, the rate of mesothelioma was higher for those who had lived in the town a greater length of time. However, a study of 4,768 residents of the town–none of whom had worked at the mine or mill, but nonetheless had suffered exposure–showed that men suffered from the cancer at a rate four times that of women, all other factors being equal. However, women were shown to have a “steeper dose-response curve,” meaning that women who did develop mesothelioma were likely to do so at lower levels of exposure. Interestingly, those who had initially been exposed to asbestos at an early age were less likely to die of mesothelioma than those whose first exposure had occurred at age 15 or later. Alison Reid and her colleagues are part of the Occupational and Environmental Epidemiology Group of the School of Population Health at the University of Western Australia in Crawley, near Perth.