Although consumption of
chrysotile asbestos has decreased since the 1970s, the latency period of
asbestos-related
cancers is thought to be at least 20-30 years, and therefore the potential health risks associated with historical exposures is still actively researched. This analysis represents an update to a previous paper in which we evaluated the exposure-response relationships for
lung cancer and
mesothelioma in
chrysotile-exposed cohorts. Here, we review several recently published studies as well as updated information from previous studies. For each of the 14 studies considered, we identified the "no-observed adverse effect level" (NOAEL) for
lung cancer and/or
mesothelioma. NOAEL values for
lung cancer ranged from 1.1 to <20 f/cc-years to 1600-3200 f/cc-years, and for
mesothelioma ranged from 100-400 f/cc-years to 800-1599 f/cc-years. The range of "best estimate" NOAELs was estimated to be 89-168 f/cc-years for
lung cancer and 208-415 f/cc-years for
mesothelioma. None of the six cohorts of cement or friction product manufacturing workers exhibited an increased
lung cancer risk at any exposure level, while all of the five studies of textile workers reported an increased risk at one or more exposure levels. This is likely because friction and cement workers were exposed to much shorter
chrysotile fibers. Of the seven cases of peritoneal
mesothelioma reported in the included studies, none were observed in the analyses of cement or friction product manufacturing workers in the absence of
crocidolite exposure. These findings will help characterize potential worker and consumer health risks associated with historical and current
chrysotile exposures.