A critique of the use of hormesis in risk assessment.
There are severe problems and limitations with the use of hormesis as the principal dose-response default assumption in risk assessment. These problems and limitations include: (a) unknown prevalence of hormetic dose-response curves; (b) random chance occurrence of hormesis and the shortage of data on the repeatability of hormesis; (c) unknown degree of generalizability of hormesis; (d) there are dose-response curves that are not hormetic, therefore hormesis cannot be universally generalized; (e) problems of post hoc rather than a priori hypothesis testing; (f) a possible large problem of 'false positive' hormetic data sets which have not been extensively replicated; (g) the 'mechanism of hormesis' is not understood at a rigorous scientific level; (h) in some cases hormesis may merely be the overall sum of many different mechanisms and many different dose-response curves - some beneficial and some toxic. For all of these reasons, hormesis should not now be used as the principal dose-response default assumption in risk assessment. At this point, it appears that hormesis is a long way away from common scientific acceptance and wide utility in biomedicine and use as the principal default assumption in a risk assessment process charged with ensuring public health protection.
Kitchin
Kirk T
KT
Environmental Carcinogenesis Division National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA. kitchin.kirk@epa.gov
Drane
J Wanzer
JW
D000818:Animals; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D014116:Toxicology