Mesothelioma rates in South Africa: trends 1995-2008

Abstract

Background: Mesothelioma is a rare neoplasm which is caused by asbestos exposure. South Africa has mined and refined all three types of asbestos since 19th century with the peak of production in1940-1980s. At present asbestos use and production is banned in South Africa. Trend 1995-2008 in mesothelioma rate was assessed to determine burden of asbestos related deaths due to mesothelioma by year and gender. Methods: Death certificates with underlying cause of death stated as C45 were selected for the study in 1995-2008. For each year of study, age and gender distribution was obtained from the national statistical releases. Mesothelioma rates, 95% confidence interval were calculated for each year and sex, and for age groups and sex .Poisson regression was used to test for trend. Results: In total 2497 cases were identified of deaths due to mesothelioma, 1919 in men and 578 in women in the study period. There was 3:1 male to female ratio. The trend was stable and constant over time for both men and women cases. Mortality rate in men was 8-16 per million and in women 2-5 per million respectively Conclusion: If mortality rate remains at current estimates we can expect 2 134 cases until 2020. These mortality rates are much lower than expected, given the historical production and use of, and high exposure to, asbestos in South Africa. Possible reasons for this are discussed, including the effect of HIV which has been instrumental in reducing the life expectancy of South Africans in the last two decades. Asbestos-exposed individuals may not live long enough to develop mesothelioma. Competing causes of death need to be taken into account when constructing models to predict mesothelioma mortality rates.