Exposure–response relationship between chrysotile exposure and mortality from lung cancer and asbestosis

Abstract

The study confirmed strong associations between exposure to chrysotile asbestos and lung cancer and asbestosis, in which clear exposure-response relationships were observed.

A comparison of parallel dust and fibre measurements of airborne chrysotile asbestos in a large mine and processing factories in the Russian Federation

“…Other studies reporting conversions of dust were predominantly in other industries or using different measurement methods or units of measurements thus making the resulting conversion factors difficult to compare (Deng et al, 2012;Loomis et al, 2009;Dodic-Fikfak, 2007;Dement et al, 2009). Many were in textile factories where finished, enriched asbestos is used compared to Uralasbest where the processing involved multiple stages of crushing and enriching asbestos containing ore.…”

“…Some parts of textile manufacturing could be compared to the Uralasbest "Final product (packaging)" unit, where the enriched asbestos is packaged for commercial use. A chrysotile asbestos textile plant in Chongqing, China, the fibre to dust ratio in the raw materials workshop was 2.32, twice as high as the ratio from Uralasbest for "Final product (packaging)" (Deng et al, 2012). This study used a similar gravimetric measurement method for assessing the dust concentration and a similar counting method for fibres as the Asbest Study but, although it was not reported by Deng et al (Deng et al, 2012), the samplers used and their efficiency were most likely different to those used at Uralasbest.…”

“…Cumulative fibre years (either measured or estimated from dust) is the most common exposure index (Dement et al, 1983a;Deng et al, 2012;Elliott et al, 2012;Hein et al, 2007;Loomis et al, 2009;Loomis et al, 2012;Sichletidis et al, 2009;Wang et al, 2013), however exposure has also been estimated based on profession or other occupational history characteristics (Acheson et al, 1982;Mirabelli et al, 2008;Ohlson and Hogstedt, 1985 considered to be a more relevant metric than dust concentration as fibres can be isolated from other airborne particles, where dust also includes other airborne materials, not exclusively asbestos (Harries, 1971;Dement et al, 2008). However, comprehensive fibre concentrations are not always available and often derived from historic dust concentrations using conversion factors, which is not without its challenges (Deng et al, 2012;Dement et al, 1983b;Lin et al, 2014;Liddell et al, 1997;McDonald et al, 1984;Council of the European Communities, 1987;Dodic-Fikfak, 2007). Although there have been efforts to develop a standard conversion factor to convert asbestos dust concentrations to fibre (Council of the European Communities, 1987), evidence shows that conversions are dependent on industry, asbestos based activity type, asbestos type and other environmental airborne materials (Peto, 1989;Puledda and Marconi, 1991).…”

How conflicted authors undermine the World Health Organization (WHO) campaign to stop all use of asbestos: spotlight on studies showing that chrysotile is carcinogenic and facilitates other non-cancer asbestos-related diseases

“…4. The recently published 37-year follow-up cohort studies with chrysotile asbestos miners and textile workers in China by Wang et al [19][20][21][22] and Deng et al 23 showing significant dose-dependent mortality of mesothelioma/lung (SMR 1.46; 95% CI, 0.50, 4.30, P,0.001), larynx, and other cancers as well as of non-malignant disorders 24 . Lung cancer increased with employment years at entry to the study by 3.5-fold in 10 years, and 5.3-fold in 20 years.…”

“…The authors showed significant exposure-response relationship with causal links between chrysotile asbestos exposure and lung cancer and non-malignant respiratory diseases. [19][20][21][22][23] The strength of these latter studies by Wang et al [19][20][21][22] is that subjects were exposed to relatively pure chrysotile. As a result of geographical features with the remote location of the mine, workers usually remained with the mine for a lifetime with little opportunity to change their job, eliminating exposure to other occupational carcinogens.…”