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Have your say – draft opinion on non-monotonic dose-response

Our scientists’ proposal for an approach to evaluate the possible presence of ‘non-monotonic dose-response’ relationships for chemicals is open for comments. EFSA calls on the scientific community, regulatory advisory bodies and other interested parties to send your feedback by the deadline of 4 February 2021.

The concept of non-monotonic dose response (NMDR) challenges a critical assumption in chemical risk assessment: harmful effects increase with the dose until reaching a maximum level for people or animals. This draft scientific opinion follows up on previous work by EFSA including an update on non-monotonic dose response and a scientific colloquium on low dose response in toxicology and risk assessment.

What does the draft opinion on NMDR say?

  • There is no gold standard for the statistical analysis of NMDR of chemicals. EFSA’s experts looked at different approaches and concluded that a combination of approaches would be preferable during the evaluation of ‘apparent’ NMDR.
  • For some biological effects a NMDR is clearly plausible and these cases are well covered by current risk assessment principles.
  • Our scientists have also observed other cases with ‘apparent’ NMDR at molecular level and also possibly with some adverse effects in humans.
  • To cover these cases, EFSA’s experts developed an approach and applied it to two substances used in food contact materials – bisphenol A (BPA) and the phthalate DEHP – as case studies. They concluded: no indications of NMDR were detected for BPA, while there were indications of a biologically plausible NMDR for DEHP and this should be further investigated in future work.

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