Abstract:
OBJECTIVE:To determine how information on chemical
constituents of different smokeless tobacco products
(STPs) may be used in cancer risk assessment for
regulatory purposes.
METHODS:This study investigated select STP
constituents potentially associated with significant
cancer risk by applying a known toxicological risk
assessment framework. Cancer risk estimates were
obtained for selected constituents of STPs and
a medicinal nicotine gum formulation with comparable
toxicity information and also median concentration data
on the GothiaTek analytes. The calculated cancer risk
was considered ‘unacceptable’ if it exceeded the US
Environmental Protection Agency’s (USEPA’s) benchmark
of an ‘acceptable’ cancer risk of 10E 6.
RESULTS:The cancer risk estimates derived from daily use
of 10 g of STPs meeting the industry-set GothiaTek limits
exceed the levels generally considered ‘acceptable’ by
the USEPA at least 8000 times. Except for the medicinal
nicotine tested, all the STP types, including the relatively
lower tobacco specific nitrosamine (TSNA)-containing
snus, were found to carry an ‘unacceptable’ cancer risk.
The calculated cancer risks associated with the snus and
the US moist snuff products were, respectively, at least
1000 times and 6000 times greater than the minimum
acceptable. TSNA and cadmium are associated with the
largest estimated cancer risks for all the STPs evaluated.
CONCLUSIONS:This study’s findings provide an empirical
risk assessment that could guide STP regulation using an
existing toxicological assessment framework. The study
findings question the scientific rationale of the industryset
standards and highlight the need for regulatory
actions to reduce specific toxicants in all STPs.
