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Chemicals Causing Hormone Changes

The Endocrine Society is the world’s largest and most active organization devoted to hormone research. It recently published an update of its 2009 scientific literature review which reaffirmed its earlier conclusions that exposure to some environmental contaminants contributes to infertility, some cancers, and neurological disorders, as well to increasing frequency of Type 2 diabetes and obesity development;[1] these last two concerns are considered to be among the greatest public health perils confronting society today. Other scientists from various institutions, universities and organizations, such as the American Chemistry Council, have also reviewed the literature and examined the published findings regarding this statement in order to add scientific perspective and depth.[2] However, the idea in the Society’s summary, that environmental contaminants can harm one’s health is not new. Government agencies throughout the world routinely act to protect the public’s health by studying and critically evaluating the toxicity and exposure patterns of such contaminants, including ones that affect the hormone system. Importantly, these agencies determine the safe or virtually safe levels of these contaminants for humans, including sensitive folks (see for example, http://toxnet.nlm.nih.gov/newtoxnet/iter.htm). This government work to establish safe doses is important, since it is well known that both natural and synthetic chemicals are toxic at some level of exposure (see: http://kidschemicalsafety.org/topics/safe/).

The Endocrine Society maintains that a particular type of toxicity, i.e., changes in hormone function (“endocrine disruption”) should be evaluated differently than other kinds of effects environmental contaminants may produce. Publications that appear to support this suggestion, among many, are by Prins et al. (2011) and Vanderberg et al. (2012).[3] However, risk assessment scientists and scientific groups, including government agencies vigorously disagree that hormonal changes need to be evaluated differently from other effects. An example of this disagreement can be found in Autrup et al. (2015).[4]

Another aspect of disagreement between the Society and others is the Society’s point of view on the precautionary principle, which refers to the idea of taking precautionary measures against suspected threats to health and the environment, even when the cause of the threat has not been established scientifically.[5] However, many groups, including government agencies such as the U.S. Environmental Protection Agency (EPA),[6] do not follow the precautionary principle because most interpretations of this principle focus only on whether a chemical can cause an effect, while ignoring the amount of chemical needed to produce this effect. For example, high doses of pure drinking water affect the body’s hormone system (changing blood levels of vasopressin, an antidiuretic hormone) causing cells to swell. Drinking even larger amounts of water causes water to enter the brain leading to swelling, seizures, coma, respiratory arrest, and death. Thus, from a precautionary view, even water can be seen as an endocrine disrupter and neurotoxin. In fact, it is the dose makes the poison, a well-established principle in toxicology (see, for example, http://toxedfoundation.org/toxicity-today/), and many groups use this principle in their assessment of risk from both natural and synthetic chemical exposures.

The Endocrine Society has called for more direct cause-and-effect research; more mandatory testing for endocrine activity, particularly at environmentally low concentrations; more “green chemistry” to replace endocrine disrupting chemicals;[7] and more education of the public and policymakers to keep such chemicals out of the air, water and food chain provided effective alternative are available for beneficial consequences, e.g., compounds to prevent fires in homes when utilized at low, safe concentrations. These calls for “more” may be warranted. But what also seems reasonable—and clearly an important step—is for endocrine scientists to come to a better understanding of the current risk assessment practice and findings for these hormone-disrupting chemicals. In turn, risk assessment scientists need to evaluate the latest endocrine findings to make sure that all adverse effects are addressed. Efforts to bridge the apparent differences between these two scientific communities are underway.