By Gregory G. Bond and Daniel R. Dietrich,
The EU and U.S. governments continue to try to best identify and regulate potential endocrine-disrupting chemicals (EDCs). In an attempt to influence these efforts, the Endocrine Society – a global association representing endocrinologists and related experts – published a series of economic papers in 2015 and 2016 estimating annual health care costs due to EDC exposure in the hundreds of billions of euros and dollars. While significantly flawed, these cost estimates have been used aggressively in advocacy campaigns to try to change how chemicals are tested, evaluated and regulated.
Although these estimates were initially received with some skepticism by scientists and government authorities, including the European Commission, they got widespread media coverage and continue to be cited by activists in public policy forums. As a result, we did a thorough and rigorous critique of the methodology underlying the cost estimates, which was published on 20 May 2017 in the peer-reviewed journal Archives of Toxicology.
We found that the medical burden and cost estimates were as flawed and irrelevant to public health decision-making as many experts first suspected. For example, the authors assumed causal relationships between exposures to EDCs and selected medical conditions, namely “loss of IQ” and “increased prevalence of intellectual disability,” but did not establish them via a critical weighting of sound animal toxicology and human epidemiology evidence. Consequently, the cost estimates are highly speculative and should not be used to support public policy or chemical regulation.
Since more than 75 percent of the total cost estimates for both the EU and U.S. were driven by the authors’ assessment that exposures to EDCs were causing lost IQ and intellectual disability, we scrutinized the animal toxicology and human epidemiology studies they cited for these estimates. We found the evidence to be remarkably sparse and inconsistent.
Other scientific groups also evaluated the same evidence base, using superior methods. They reported that the “evidence” fell far short of establishing a causal link between EDC exposures, lost IQ and intellectual disability. In a breach with standard scientific practice, the authors of the cost estimates neither cited these contradictory, published scientific reviews, nor explained why they arrived at different conclusions.
Although we didn’t examine in detail the studies supporting the remaining 25 percent of estimated total costs, other scientists have examined some of it, reporting similar problems. Thus, the cost estimates in their entirety appear dubious at best and should not be given any weight.
Everyone loses when the scientific method, which demands impartial objectivity, is not met as demonstrated by this series of economic papers. Not only can it undermine the credibility of individual scientists and organizations, it further erodes public acceptance of science. Moreover, public policy decisions based on poor science or isolated findings from unreplicated studies, even if well-intentioned, will have significant adverse effects on individuals and society.
Gregory G. Bond, Ph.D., M.P.H., F.A.C.E., is principal of Manitou View Consulting, LLC in Northport, Mich., USA. Daniel R. Dietrich, Ph.D.,F.A.T.S., E.R.T., is professor of human and environmental toxicology at the University of Konstanz in Konstanz, Germany.