JECFA and EFSA New Approach, Margin of Exposure

In order to avoid any quantitative estimate, the JECFA (2005) and EFSA (2005) have recommended to use an MOE approach in the assessment of compounds that are both genotoxic and carcinogenic. 

The following overview is primarily based on the following references JECFA (2005), EFSA (2005), and Larsen (2006). 

According to the OECD/IPCS definitions listed in Annex 1 (OECD 2003)  

Margin of Exposure is the Ratio of the no-observed-adverse-effect level (NOAEL) for the critical effect to the theoretical, predicted or estimated exposure dose or concentration.  

A related term is the margin of safety. According to the OECD/IPCS definitions listed in Annex 1 (OECD 2003), the margin of safety, for some experts, has the same meaning as the Margin of Exposure, while for others, the margin of safety means the margin between the RfD and the actual exposure dose or concentration. 

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