Critical comments on the WHO-UNEP State of the Science of Endocrine Disrupting Chemicals – 2012

  • a Exponent, 1800 Diagonal Road, Suite #500, Alexandria, VA 22314, USA
  • b The Tisch Cancer Institute and Institute for Translational Epidemiology, Icahn School of Medicine at Mount Sinai, 17 East 102 Street Floor West Tower, 5th Floor Room 5-142, New York, NY 10029, USA
  • c Department of Obstetrics & Gynecology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
  • d Gradient, 20 University Road, Cambridge, MA 02138, USA
  • e Exponent, The Lenz, 1st Floor, Hornbeam Park, Harrogate HG2 8RE, UK
  • f Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada


We critically review the WHO-UNEP 2012 report on endocrine disruptors.

WHO-UNEP report is not an update of the WHO-IPCS 2002 state-of-the-science review.

WHO-UNEP report should not guide evidence-based decisions on endocrine disruption.

A balanced and objective review of all available literature is needed.

An update must note controversies, data gaps, and provide supported conclusions.


Early in 2013, the World Health Organization (WHO) released a 2012 update to the 2002 State of the Science of Endocrine Disrupting Chemicals. Several significant concerns have been identified that raise questions about conclusions reached in this report regarding endocrine disruption. First, the report is not a state-of-the-science review and does not follow the 2002 WHO recommended weight-of-evidence approach. Second, endocrine disruption is often presumed to occur based on exposure or a potential mechanism despite a lack of evidence to show that chemicals are causally established as endocrine disruptors. Additionally, causation is often inferred by the presentation of a series of unrelated facts, which collectively do not demonstrate causation. Third, trends in disease incidence or prevalence are discussed without regard to known causes or risk factors; endocrine disruption is implicated as the reason for such trends in the absence of evidence. Fourth, dose and potency are ignored for most chemicals discussed. Finally, controversial topics (i.e., low dose effects, non-monotonic dose response) are presented in a one-sided manner and these topics are important to understanding endocrine disruption. Overall, the 2012 report does not provide a balanced perspective, nor does it accurately reflect the state of the science on endocrine disruption.


  • ADDM, Autism and Developmental Disabilities Monitoring Network;
  • ADHD, attention deficit hyperactivity disorder;
  • AhR, aryl hydrocarbon receptor;
  • AHS, Agricultural Health Study;
  • ASD, autism spectrum disorder;
  • BPA, bisphenol A;
  • CDC, Centers for Disease Control and Prevention;
  • DDD, dichlorodiphenyldichloroethane;
  • DDE, dichlorodiphenyldichlorethylene;
  • DDT, dichlorodiphenyltrichloroethane;
  • DES, diethylstilbestrol;
  • DNA, deoxyribonucleic acid;
  • DNT, developmental neurotoxicity;
  • DTU, Technology University of Denmark;
  • EDCs, endocrine disrupting chemicals;
  • EFSA, European Food Safety Authority;
  • GLP, Good Laboratory Practices;
  • GRADE, Grades of Recommendation Assessment Development and Evaluation;
  • IARC, International Agency for Research on Cancer;
  • IPCS, International Programme on Chemical Safety;
  • MOA, mode of action;
  • NMDR, non-monotonic dose response;
  • NOAEL, no observed adverse effect level;
  • NRC, National Research Council;
  • OECD, Organization for Economic Cooperation and Development;
  • PCB, polychlorinated biphenyls;
  • POP, persistent organic pollutants;
  • TBT, tributyl tin;
  • TCDD, tetrachlorodibenzo-p-dioxin;
  • TDI, tolerable daily intake;
  • TPT, triphenyl tin;
  • TRH, thyrotropin-releasing hormone;
  • UNEP, United Nations Environment Programme;
  • USEPA, United States Environmental Protection Agency;
  • USFDA, United States Food and Drug Administration;
  • WHO, World Health Organization


  • Endocrine-disrupting chemicals (EDCs);
  • Weight of evidence;
  • Causation;
  • State of the science;
  • Disease trends;
  • Low-dose effects;
  • Non-monotonic dose response (NMDR)

1. Introduction

In 2002, the World Health Organization (WHO), in collaboration with the International Programme on Chemical Safety (IPCS), produced the Global Assessment of the State-of-the-Science of Endocrine Disruptors ( WHO-IPCS, 2002). In the intervening ten years, interest in the question of endocrine disruption as a possible environmental issue has only increased and a substantial quantity of research related to endocrine disruption has been conducted. Consequently, a more current state-of-the-science review was warranted and the WHO, in collaboration with the United Nations Environment Programme (UNEP), published what is presented as an “update” to the 2002 report: State of the Science of Endocrine Disrupting Chemicals – 2012 ( WHO-UNEP, 2012a) and a companion report: State of the Science of Endocrine Disrupting Chemicals 2012 Summary for Decision-Makers ( WHO-UNEP, 2012b).