The Ramazzini Institute
for Occupational and Environmental Health Research   

Who Are We?

Study Questions Role of Viruses
In New Zealand Mesothelioma Epidemic*
    Malignant mesothelioma, a relatively rare cancer of the lining of the body, in the years 1975 to 1980, had an annual death rate in New Zealand of two per million. Tord Kjellstrom and Pamela Smartt of the University of Auckland have established that the rate for men reached 25 per million for 1995, and that the incidence is expected to double by 2010.
     Decades of studies, including prior epidemiological research by Kjellstrom, have established an association between asbestos exposure and cancer, as well as with an increase of fibrous tissue in the lungs [asbestosis]. He and Pamela Smartt calculate that for each case of mesothelioma, there are three to eleven other cases of asbestos-induced cancer in the lung and other sites. Thus the increase in mesothelioma is an index of a broader epidemic.
     Not all cases of mesothelioma are clearly associated with asbestos. Other causes have been hypothesized. Molecular biologist Michael Carbone, in laboratory studies, and statistician Julian Peto in a study of mesothelioma in British populations, suggest that SV40 [simian virus 40], a contaminant of some early polio vaccines, might contribute to the development of human mesothelioma by binding the gene p53, making cells more susceptible to the action of asbestos.
     The New Zealand investigators point out that cases of mesothelioma in females is much smaller than in men [49 versus 357] in the years 1980 to 1996, increased at a slower rate, and were concentrated at different sites. Most asbestos exposure occurs in mainly male-dominated occupations such as construction, shipbuilding, power plants and asbestos product production.
     "The difference in the trends for males and females...does not support SV40 exposure itself being the cause of [the] epidemic in males, as this would affect men and women equally. This cohort of vaccinated people is still relatively young so it is too early to tell if mesothelioma increases have been heightened by SV40 infection," the authors report.
     The import of crude asbestos into New Zealand [four kilograms per capita] peaked in 1974, and declined steeply thereafter. The "delayed exposure-response" has "a time lag of 13-70 years." The increase in the mesothelioma rate "is similar to the increase of annual asbestos imports into New Zealand from 1949 to 1970."
     The authors conclude that their data "strongly support" the belief that the epidemic of mesothelioma is occupationally associated with the "increase of asbestos use about 30 years earlier".

*Tord Kjellstrom and Pamela Smartt, New Zealand Medical Journal.
Increased mesothelioma incidence in New Zealand: the asbestos-cancer epidemic has started. Nov. 24, 2000; 113,1122:485-90