Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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benzene in the causation of multiple myeloma. Also
reviewed
are recent advances in the detection of specific chromosome
lesions in myeloma cells and those associated with drug and
chemical exposure. Epidemiological studies from the
United
States, Canada, United Kingdom, China, Italy, the
Scandinavian countries, China and other countries were
reviewed. Based on a thorough review and analysis of the
existing scientific data according to well–established
criteria, the authors concluded that: (1) There is strong
evidence linking high levels of exposure to benzene with an
increased risk of developing acute myelogenous leukemia.
The evidence of this association satisfies all the Hill’s
criteria, and the relationship can be judged as causal in
nature. Furthermore, cell–type specific analysis indicates
that the threshold is most likely to be around 370 to 530
ppm–years. (2) In contrast, there is no scientific
evidence to support a causal relationship between exposure
to benzene or other petroleum products and the risk of
developing multiple myeloma.
Source: EXXON Biomedical Sciences East Millstone, NJ
Reliability: (1) valid without restriction
07–JUL–2005 (97)
Remark: Review of leukemia cell–type specific risks in
epidemiologic
studies of benzene workers.
The purpose of this document was to review the human
epidemiologic studies on benzene with respect to leukemia
cell types. While benzene is clearly linked to leukemia in
humans, the question of whether this effect is cell type
specific is important. First, if benzene were causally
linked to all leukemia cell types, the burden of benzene
over–exposure would be larger. Secondly, in the quest to
find a mechanistic explanation for benzene–induced
leukemia,
current views are that the cell type would be important.
Five studies were selected from a set of 16 studies because
they satisfied the two attributes that: (1) benzene
exposure
was measured quantitatively and (2) leukemia cell types
were
specified. These two features allow a formal assessment of
dose response for benzene and leukemic cell types, an
essential element for determining causality. The studies
of
Crump, 1994; Bond et al., 1986; Hayes et al., 1997; Rushton
and Romaniuk, 1995; Ireland, 1997 were reviewed. General
findings and conclusions of this review include the
following. There is sufficient evidence to conclude that
acute non–lymphocytic leukemia (ANLL) shows a dose response
relationship with benzene. All five of the studies that
are
reviewed here provide either strong evidence or at least
some indication of a possible relationship. To date, there
Appendix D: Benzene SIDS Dossier
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