Can exposure characterization explain concurrence or discordance between toxicology and epidemiology?
The importance of reliable exposure assessment, as a key component of the overall risk assessment process, has been well described for some considerable time. Yet, despite this widely accepted tenet, many studies conclude significant adverse health effects, with associated public policy implications, in the absence of adequate or, in some cases, even rudimentary, exposure quantification. Moreover, it appears that epidemiological studies in humans and toxicological studies in experimental animals may both suffer from inadequate exposure assessment. In this review, we discuss the nature and quality of the exposure assessment in both epidemiologic and toxicologic studies using examples from the pesticides and phthalate literature. Each type of study has its strengths and weaknesses in how exposure is assessed and often the strength of one is also a weakness. It would appear that insufficient or incomplete information about differences in exposure assessment could explain, at least in some
