With the CDC’s recent admitted omissions of data correlating vaccines to autism, more information continues to emerge on other factors which are “highly likely” to contribute to the incidence of autistic spectrum disorder (ASD). A growing body of literature is also reporting strong associations between the disorder and pesticide exposures during pregnancy.
Anti-vaccine advocates have sharply criticized the medical community for the rise in vaccination scheduling and frequency as a primary cause of autism. Although vaccines are certainly a contributor to ASD, they are not the smoking gun in terms of causation. If they were, then a much higher percentage of children receiving vaccines would exhibit symptoms of the disorder.
The disorder likely has a number of causes involving synergistic toxicity between vaccines, the environment and some degree of genetic susceptibility.
Case Control Study
The study included 486 children diagnosed with an ASD, 168 diagnosed with delayed development, and 316 controls from the ongoing Childhood Autism Risks from Genes and Environment (CHARGE) study, which was launched in 2003. The researchers assessed timing and extent of pesticide applications within 1.75 km of each mother’s residence from 3 months before conception through the time of delivery. These data came from California’s Pesticide Use Report, which since 1990 has documented pesticide applications to farmland, golf courses, cemeteries, and other sites down to the square mile
The study examined the association between prenatal proximity to fields where organophosphate, pyrethroid, or carbamate pesticides were applied and later diagnosis of neurodevelopmental disorders including ASDs and developmental delays. The authors found the strongest associations between ASDs and application of nonspecified organophosphates during the third trimester as well as one specific organophosphate, chlorpyrifos, during the second trimester. They also report statistically significant associations between ASDs and pyrethroid application both preconception and during the third trimester, as well as an association between carbamate application and developmental delay, although this estimate was based on a small number of cases.
The new research supports associations reported in previous work, says Kirsten Brandt, a senior lecturer at the School of Agriculture, Food, and Rural Development at University of Newcastle, United Kingdom, who was not involved in the study. First author Janie Shelton, a graduate student in the Department of Public Health Sciences at the University of California, Davis, says the most important finding was the association between chlorpyrifos and ASDs. The compound is banned for residential use but is one of the most commonly used agricultural chemicals, she says, noting that pesticides can drift beyond buffer zones around the point of application and into homes and workplaces.
It is known that some birth malformations are caused by de novo genetic events, such as large copy number variants that have been found to increase the risk for ASD by approximately 400%. Single-gene deletions, are known to cause CHARGE syndrome associated with genital abnormalities and putatively associated with ASD. However, these genetic events may have currently poorly identified environmental triggers, and 70 to 80% of male congenital malformations of the reproductive system have no clear genetic causes. Instead, they appear to be driven by specific environmental insults that were not serious enough to lead to more serious adverse events during pregnancy, such as spontaneous abortion.
“Essentially what happens is during pregnancy…there are certain sensitive periods where the fetus is very vulnerable to a range of small molecules — from things like plasticisers, prescription drugs, environmental pesticides and other things. Some of these small molecules essentially alter normal development. Autism appears to be strongly correlated with rate of congenital malformations of the genitals in males across the country, this gives an indicator of environmental load and the effect is surprisingly strong. The strongest predictors for autism were associated with the environment; congenital malformations on the reproductive system in males.” stated Andrey Rzhetsky, Professor of Genetic Medicine and Human Genetics at the University of Chicago.
Glyphosate is an herbicide produced and marketed by Monsanto Corporation, the agrochemical and biotechnology giant. Monsanto claims that glyphosate is safe and has successfully lobbied the Environmental Protection Agency to raise the residue limits of this toxic chemical.
Independent scientists disagree with Monsanto: several recently published peer-reviewed studies point to serious health impacts from exposure to this toxic herbicide.
Roundup herbicide may also be the most important factor in development of autism and other chronic disease. Glyphosate does induce disease and is a “textbook example of exogenous semiotic entropy.” Glyphosate inhibits detoxification of xenobiotics and interferes with cytochrome P450 enzymes, which enhances the damaging effects of other chemical residues and toxins, and very slowly damages cellular systems in the body through inflammation. Residues of glyphosate are found in sugar, corn, soy, and wheat, some of the main components of the Western diet.
One such study, published in the journal Ecotoxicology, found that glyphosate is toxic to water fleas (Daphnia magna) at minuscule levels that are well within the levels expected to be found in the environment.
According to regulators, glyphosate is thought to be practically nontoxic to aquatic invertebrates. The water flea is a widely accepted model for environmental toxicity, so this study throws serious doubt on glyphosate’s classification as environmentally safe.
Despite any limitations in the study, Philippe Grandjean, an adjunct professor of environmental health at the Harvard School of Public Health adds, “The researchers must be praised for having been able to link data on pesticide usage to geocoded residences during pregnancy.” Joseph Braun, an assistant professor in the Department of Epidemiology at Brown University, describes the work as “the cutting edge of research into environmental determinants of autism.” Braun also was not involved in the study.
The study provides new directions for exploration. “Until about five years ago, virtually all research on autism assumed that the disease was entirely genetic in origin, and that environmental exposures did not play a role,” says Robert Wright, director of the Division of Environmental Health at Mount Sinai School of Medicine, who was not involved in the research. “Rising rates of autism and failure to find genetic causes despite a multitude of very large genetic studies has led to a major shift in focus in the field. These chemicals are a solid lead that needs to be followed.”