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There is a critical need for all regulatory decisions to be made on the basis of credible scientific evidence, largely based on peer-reviewed studies published in credible journals. The interpretation of scientific data is not always clear-cut because of many variables, especially where there are gaps in the data. Publishing these in journals so that they are available for all the relevant stakeholders to read and analyze allows for a wider and more critical debate over the data and for more rigorous processes in reaching conclusions.

One of the most important aspects of this scientific process is that studies should clearly document the materials and methods used in research experiments. Many of the studies showing the adverse effects of pesticides and problems with current regulatory methodologies get criticized through academic and political debates. The accepted way to resolve the credibility of research is to accurately repeat the experiment by using the material and methods described in the published paper to see if they consistently produce the same results. This will in most cases confirm if the research conclusions are correct. One of the methods used at times by the pesticide industry and regulators to rebut studies is to state that industry studies fail to report the same adverse outcomes. These industry studies are largely unpublished and are usually based on different criteria than the peer-reviewed studies they are meant to refute. Setting up research using different criteria will most likely result in different outcomes. When the outcomes of these “similar” studies do not confirm the results of the study with adverse health outcomes, the pesticide industry and regulators use them to discredit the potentially profit-damaging study and dismiss its results.

A good analogy would be if an organization performed a few studies on a select number of elderly people who smoke tobacco and then announced that “studies” show no evidence that smoking reduces a person’s life span, as these people have lived long lives while smoking every day. Tobacco proponents could then use these biased studies as “evidence” that the hundreds of other studies linking smoking tobacco to numerous health issues should be ignored because the results are “not proven.”

An example was given by Dan Fagin in a comment article that he wrote in Nature in 2012, a few months after of the publication of the comprehensive meta review on endocrine disruption by Vandenberg et al. He mentions two separate studies that were conducted on the plasticizer bisphenol A (BPA) to assess if it is an endocrine disrupter. One study was conducted by the U.S. Food and Drug Administration (FDA) and the other by a private firm that was contracted by industry. Neither study found evidence of endocrine disruption by BPA, despite numerous other studies finding this. Vandenberg et al., for example, reported that “In 2006, vom Saal and Welshons . . . examined the low-dose BPA literature, identifying more than 100 studies published as of July 2005 that reported significant effects of BPA below the established LOAEL, of which 40 studies reported adverse effects below the 50µg/kg·d safe dose set by the EPA and U.S. Food and Drug Administration (FDA).”

Substantially more studies have been published since 2005 showing the endocrine-disrupting effects of BPA. Because regulatory authorities take a reactionary approach rather than a precautionary approach, one study confirming the status quo tends to take precedence over the many studies that challenge it.

According to Fagin, largely because of these two studies, neither the U.S. FDA nor the U.S. EPA will alter their risk assessments for BPA despite more than a hundred published, peer-reviewed scientific studies showing adverse health effects. “The FDA still says that BPA has no adverse effects at levels below 50 milligrams per kilogram of body weight per day—a level that vom Saal contends should actually be two million times lower, at 25 nanograms.”

The vom Saal quoted by Fagin is Dr. Frederick vom Saal, PhD, a neurobiologist and professor at the University of MissouriColumbia. He is a leading and pioneering scientist in the field of endocrine disrupters and has been since the 1970s. He was one of the coauthors of the Vandenberg et al. meta review. Vom Saal stated that both of the studies conducted by the industry and the FDA used criteria that were not suitable for finding the effects of endocrine disruption. Parts of the design of the two experiments were regarded by vom Saal and other expert researchers in the field of endocrine disruption as insensitive to low-dose effects, and consequently they would not be found in the results.

Vandenberg et al. give many examples of the way the differences in the design of experiments will result in outcomes that will not confirm the earlier studies. “In fact, the NTP [National Toxicology Program] low-dose panel itself suggested that factors such as strain differences, diet, caging and housing conditions, and seasonal variation can affect the ability to detect low dose effects in controlled studies.”

A review of the studies that were used to refute the toxic effects of low doses of atrazine found many flaws in the design of the experiments. “Hayes’ work also clearly addressed the so called irreproducibility of these findings by analyzing the studies that were unable to find effects of the pesticide; he noted that the negative studies had multiple experimental flaws, including contamination of the controls with atrazine, overcrowding (and therefore underdosing) of experimental animals, and other problems with animal husbandry that led to mortality rates above 80%.”

These examples highlight the need to accurately replicate the material and methods used in the original studies to test whether their results are credible rather than designing similar studies using variations of the materials and methods. In reality these “similar” studies are new studies because they are using a different set of criteria. They are not replicating the original study, and therefore it should not be expected that they get the same results as the original study.

Similarly, just because one study does not find an adverse health outcome like cancer or endocrine disruption, it does not necessarily invalidate a study that does. It usually means that the studies are using different criteria and methodologies. Glyphosate is a good example: several animal feeding studies did not find any evidence of cancer, but there is a study linking glyphosate to non-Hodgkin’s lymphoma. There are several studies linking it and its formulations to gene mutations, cell-cycle disregulation, and chromosomal aberrations. These types of genetic damage can be precursors to cancer. A study of human breast cancer cells found that glyphosate caused a rapid multiplication of the cancer cells. Instead of dismissing the studies, regulatory authorities need to investigate the criteria and methodologies used in these studies in order to fully understand why the cancer growths and pre-cancer events occurred.

The strategy of using studies that do not find adverse health problems to cast doubt on the credibility of a study that has is a tactic used by some industries and regulators. Big tobacco, the lead industry, and the asbestos industry did this for decades before public pressure working in partnership with concerned scientists finally forced the governments and regulatory authorities to implement some of the necessary changes. This inaction has resulted in and continues to cause millions of people to suffer from painful and needless illnesses and early deaths. Most recently this technique was used to sow the seeds of doubt about the science of human-created greenhouse gases as the major cause of climate change as well as junk food composed of empty calories as a cause of the global obesity epidemic.

The pesticide industry has a long history of muddying the waters with false comparisons like this and has been very successful at convincing most people to believe the myths that their food is safe.

About the Author:

André Leu is the author of The Myths of Safe Pesticides and Poisoning Our Children. He previously served as president of IFOAM — Organics International and is currently the international director of Regeneration International. André has over 40 years of experience in all areas of organic agriculture, from growing, pest-control, weed management, marketing and post-harvest transport to grower organizations, developing new crops and education – not only in his home country Australia, but across Asia, Europe, the Americas and Africa. He has written and published extensively in magazines, newspapers, journals, conference proceedings and newsletters in print and online on many areas of organic agriculture including climate change, the environment and the health benefits of organic agronomy. André and his wife, Julia, run an organic tropical fruit orchard in Daintree, Queensland, Australia.

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