Monsanto Response: de Vendomois (Seralini) et al. 2009

(A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health)
Regarding: MON 863, MON 810 and NK603

Assessment of Quality and Response to Technical Issues

Synopsis:
The laboratory findings primarily related to kidney and liver function reflect the large proportion of tests applicable to these organ systems. This is not a defect in the design of the study, but simply the reality of biochemical testing - there are good clinical tests of these systems which are reflected in blood chemistry. The function of other organ systems is assessed primarily via functional assessment, organ weight, and organ pathology rather than through blood or urine biochemical assays.

The authors apply a variety of non-standard statistical approaches. Each unique statistical approach and each comparison performed increases the number of statistically significant findings which will occur by chance alone. Thus, the fact that de Vendomois et al. find more statistically significant findings than reported in the Monsanto analysis is entirely expected. The question, which de Vendomois et al. fail to address, is whether these non-routine statistical tests contribute anything of value to a safety assessment. Do they help to ascertain whether there are biologically and toxicologically significant events? In our opinion (consistent with prior reviews of other publications from Seralini and colleagues) they do not.

The authors undertake a complex “principle component analysis” to demonstrate that kidney and liver function tests vary between male and female rodents. This phenomenon is well-recognized in rodents (and, for that matter, humans) as a matter of gender difference. (This does not indicate any toxic effect, and is not claimed to do so by the authors, but may be confusing to those not familiar with the method and background.)

De Vendomois et al. appear to draw from this a conclusion that there is a gender difference in susceptibility to toxic effects. While such differences are possible, no difference in susceptibility can be demonstrated by gender differences in normal baseline values. Utilizing this alleged difference in gender susceptibility, the authors proceed to identify statistically significant, but biologically meaningless differences (see next bullet) and to evaluate the extent to which these changes occur in males verses females.
De Vendomois et al. fail to consider whether a result is biologically meaningful, based on the magnitude of the difference observed, whether the observation falls outside of the normal range for the species, whether the observation falls outside the range observed in various reference materials, whether there is evidence of a dose-response, and whether there is consistency between sexes and consistency among tested GM materials. These failures are similar to those observed in previous publications by the same group of authors.

While the number of tests that are statistically significant in males verses females would ON AVERAGE be equal in a random distribution, this ratio will fluctuate statistically. The authors have not, in fact, demonstrated any consistent susceptibility between genders, nor have they demonstrated that the deviations from equality in regards to numbers of positive tests fall outside of expectation. For example, if you flip a coin 10 times, on average you will get 50% heads and 50% tails but it is not unusual to get 7 heads and 3 tails on a particular 10 tosses. If you do this over and over and consistently get on average 7 heads and 3 tails then there may be something different about the coin that is causing this unexpected result. However, de Vendomois et al. have not shown any such consistent difference.

While de Vendomois et al. criticize the lack of testing for cytochrome P450, such testing is not routinely a part of any toxicity testing protocol. These enzymes are responsible for (among other things) the metabolism of chemicals from the environment, and respond to a wide variety of external stimuli as a part of their normal function. There is no rational reason to test for levels of cytochromes in this type of testing, as they do not predict pathology. De Vendomois et al. could have identified thousands of different elements, enzymes and proteins that were not measured but this does not indicate a deficiency in the study design since there is no logical basis for testing them.

While de Vendomois et al. criticize the occurrence of missing laboratory values, the vast majority of missing values are accounted for by missing urine specimens (which may or may not be obtainable at necropsy) or by a small number of animals found in a deceased condition (which are not analyzed due to post-mortem changes). Overall, despite the challenges in carrying out such analyses on large numbers of animals, almost 99% of values were reported.

The statistical power analysis done by de Vendomois et al. is invalid, as it is based upon non-relevant degrees of difference and upon separate statistical tests rather than the ANOVA technique used by Monsanto (and generally preferred). The number of animals used is consistent with generally applicable designs for toxicology studies.

Prior publications by Seralini and colleagues in both the pesticide and GM crops arenas have been found wanting in both scientific methodology and credibility by numerous regulatory agencies and independent scientific panels (as detailed below).

In the press release associated with this publication, the authors denounce the various regulatory and scientific bodies which have criticized prior work, and claim, in advance, that these agencies and individuals suffer from incompetency and/or conflict of interest. In effect, the authors claim that their current publication cannot be legitimately criticized by anyone who disagrees with their overall opinions, past or present.

It is important to note that several scientific groups and regulatory agencies have reviewed this study, and reject and/or refute the claims of the authors:

The French High Counsel on Biotechnology (HCB) has considered both the de Vendomois (2009) and Seralini (2007) papers and has found that these papers make no useful contribution to the safety assessment.

The Food Standards Australia New Zealand (FSANZ) have also dismissed this study, stating, “Séralini and colleagues have distorted the toxicological significance of their results by placing undue emphasis on the statistical treatment of data, and failing to take other relevant factors into account.”

To summarize, as with the prior publication of Seralini et al. (2007), de Vendomois et al. (2009) uses non-traditional and inappropriate statistical methods to reach unsubstantiated conclusions in a reassessment of toxicology data from studies conducted with MON 863, MON 810 and NK603. Not surprisingly, they assert that they have found evidence for safety concerns with these crops but these claims are based on faulty analytical methods and reasoning and do not call into question the safety findings for these products.

http://www.monsanto.com/products/techandsafety/fortherecord_science/2010/monsanto_response_de_vendomois.asp