You have a number of questions and comments, and I will try to address each one of them.
Having worked in our Product Safety Center and now in Stewardship, I can assure you that the safety of our products is of critical importance to my colleagues and me. When we see claims that glyphosate is associated with neural tube defects or any other adverse health effect, we take them very seriously and review all relevant information.
Let’s first talk about what we know about glyphosate. Glyphosate inhibits the growth of plants by blocking an enzyme found in plants. This enzyme is not found in humans, fish, birds, insects or any other type of wildlife. Glyphosate has undergone extensive toxicology testing over the last 40 years, with at least six separate toxicology data sets generated by different registering companies across the globe. These data are remarkably consistent, and there is no evidence in any of those studies that glyphosate produces neural tube defects, like anencephalitis. Glyphosate is registered in 166 countries around the world, and the consensus of regulatory authorities and scientific bodies (e.g. the World Health Organization) is that glyphosate is not carcinogenic, genotoxic, neurotoxic or immunotoxic, has no endocrine disruption potential and does not impact reproduction or cause birth defects. Glyphosate has an excellent toxicological profile and there is no scientific evidence that it poses a potential hazard to an unborn child.
The allegation that glyphosate is linked to cases of anencephaly in Washington state is simply not true. Researchers from the Centers for Disease Control (CDC) assisted the Washington State Department of Health (DOH) to investigate the affected pregnancies in a three-county area. A clear cause of the increased rate of anencephaly was not determined. The Washington State DOH emphasized the importance of folic acid supplementation for women of childbearing age and recommended monitoring private wells for nitrates because of their potential association with birth defects and other adverse health outcomes. Glyphosate was not mentioned as a potential cause in these cases by either CDC or the Washington State DOH.
The Rull et al. references cited by Antoniou et al. report the results of an epidemiology study where the authors linked the mother’s address with agricultural pesticide use reports of 59 products and crop maps. There was no observation of the pesticide applications and no actual measurement of maternal exposure to the pesticides; the mothers were considered ‘‘exposed’’ to a particular pesticide if any crop type within a designated radius (1,000 m) surrounding the mother’s residence was treated with that product. There was no verification of the mother’s addresses, and given that the addresses were self-reported by the mothers in some cases almost four years after the delivery of the child, there may be some recall error in the data. Rull et al. (2006) analyzed the data several ways and found that with one model, glyphosate was weakly associated with anencephaly, but modeled another way it had no association. Given that the one association is weak and not repeated in another model, limitations exist in the exposure assessment, no other epidemiology studies have reported an association between glyphosate and neural tube defects and there is no evidence of neural tube defects in toxicology studies conducted with glyphosate, this one publication does not provide any scientific evidence that glyphosate produces neural tube defects in humans.