10 Jan 2014

What are the differences between endocrine active substances and endocrine disruptors?

If you missed it, the Scientific Commission (SC) of the European Food Safety Authority (EFSA) released an Opinion on the state of the science related to the hazard assessment of endocrine disruptors and whether current tools were sufficient to elucidate the endocrine activity/disrupting properties of these chemicals (EFSA, 2013). This is an important and useful reference document as it outlines key definitions, provides an overview of what current tests are available (or are under development), and outlines where more research is needed.

The SC made a clear distinction between endocrine active substances and endocrine disruptors, the latter being those substances that not only interact with the endocrine system, but result in an endocrine-related adverse effect.

Key conclusions:

  1. For a substance to be considered an endocrine disruptor there must be a) an adverse effect (in an organism or offspring), b) endocrine activity, and c) a plausible causal relationship between the endocrine activity and the adverse effect;
  2. The definition of "adverse" could not be specifically defined for endocrine disruptors, and as such it must be determined on a case-by-case basis using expert judgement;
  3. There are generally sufficient tools to evaluate the endocrine activity of substances related to the estrogen, androgen, thyroid, and steroidogenesis (EATS) hormone pathways in mammals and fish (although full lifecycle tests are still needed for mammals).
  4. There is a lack of understanding in the importance of non-EATS pathways in endocrine disorders, a lack of tools in evaluating non-EATS pathways related to all species (although some EATS pathway tests may capture some non-EATS endpoints), and limited tools in evaluating endocrine activity in invertebrates.

All available data information related to reversibility, critical effects, and severity, must considered in a weight-of-evidence (WoE) approach in evaluating whether a substance is an endocrine disruptor.

EFSA Report can be found here: www.efsa.europa.eu/en/efsajournal/pub/3132.htm

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