The toxicology of chrysotile-containing brake debris: implications for mesothelioma

Figures & data

Table 1. Summary of study findings on relative risk of malignant mesothelioma amongst automobile mechanics. Adapted from Kelsh et al. (2007).

Exposure	Study type	Relative risk estimate and 95% confidence interval	Reference
Auto mechanics	Cohort	NA	Jarvholm and Brisman (1988)
Auto mechanics		NA	Hansen (1989)
Bus garage workers		NA	Gustavsson et al. (1990)
Garage	Case-control	0.91 (0.35–2.34)	McDonald and McDonald (1980)
Auto service/repair		0.65 (0.80–5.53)	Teta et al. (1983)
Brake pad service/repair		1.0 (0.6–1.6)	Spirtas et al. (1985)
Auto mechanics		0.87 (0.43–1.70)	Woitowitz and Rodelsperger (1994)
Auto mechanics		0.8 (0.2–2.3)	Teschke et al. (1997)
Auto mechanics		0.62 (0.11–2.36)	Agudo et al. (2000)
Auto service/repair		0.8 (0.4–1.5)	Hansen and Meersohn (2003)
Brake pad service/repair		1.04 (0.46–2.22)	Hessel et al. (2004)
Brake pad service/repair		1.50 (0.36–6.45)	Welch et al. (2005)
Auto mechanics		1.0 (0.6–1.5)	Pan et al. (2005)
Auto mechanics		2.23 (0.53–9.35	Musk et al. (2017)
Auto service/repair	Proportionate Incidence Ratio	0	Olsen and Jensen (1987)
Auto mechanics	Proportionate Mortality Ratio	0.46 (0.24–0.80)	Coggon et al. (1995)
Auto mechanics		0.48 (0.37–0.62)	McElvenny et al. (2005)

Figure 1. The fiber pathogenicity paradigm relating physicochemical properties to fate of long and short fibers in the body. The items on the left of the diagram are parameters which dictate behavior. Adapted from Donaldson et al. (2006).

Figure 2. Diagram of the chemical structure of chrysotile and leaching mechanisms leading to dissolution and fragmentation. (I) Deposition of chrysotile fibers in the lung environment. (II) Longitudinal splitting of the fiber into thinner fibrils. (III) Leaching of magnesium from the brucitic layer resulting in the formation of a weakened metastable pseudomorph formed of the remaining silica structure. (IV) Transverse breakage of the weakened silica structure into short fragments.

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