Study Known pesticide can cause autism in children

Expectant mothers should not come into contact with a particular pesticide

Researchers now found that exposure to a notorious pesticide during pregnancy increases children's risk of developing autism.

Columbia University scientists have found in their current research that exposure to the pesticide dichlorodiphenyltrichloroethane (DDT) during pregnancy may increase the likelihood that the child develops autism. The physicians published the results of their study in the English-language journal "American Journal of Psychiatry".

Pesticides are commonly used in agriculture. Researchers found that a particular pesticide could be linked to autism in children. (Image: Dusan Kostic / fotolia.com)

DDT is banned in most parts of the world

Exposure to the notorious pesticide dichlorodiphenyltrichloroethane (DDT) during pregnancy may increase the risk of a child suffering from autism. The pesticide became famous in the 1960s and has since been banned in most parts of the world. Nevertheless, some countries still use the pesticide.

Researchers analyze data from prenatal study on autism

A research team led by Columbia University used data from Finnish mothers for a prenatal study on autism. They identified 778 children who were born between the year 1987 and the year 2005 and were diagnosed with autism. They compared the maternal blood samples taken during pregnancy with these children. Another 778 children and their mothers served as a control group. The blood samples were tested for both the pesticide DDT and its metabolite (p, p'-dichlorodiphenyl dichloroethylene; p, p'-DDE). These arise when DDT is broken down in our body. In addition, the research team measured the concentrations of another group of potentially toxic contaminants called polychlorinated biphenyls (PCBs).

How did PCB work??

There was no evidence of a relationship between autism and PCB. However, the researchers found a significantly increased risk of diagnosing autism in the child when the mother had a serum DDE level that was in the upper 25 percent. The child was also twice as likely to suffer from intellectual disability along with autism in the lowest 75 percent of DDE scores.

What is DDT?

DDT is a common synthetic pesticide that was developed in the 1940s to destroy mosquitoes on a large scale. It was so effective that it was used practically everywhere, from harvest to household use. The pesticide is very effective in combating malaria spread, explain the experts. While we care little about the pest responsible for the spread of malaria in affluent Western nations, malaria is still one of the greatest threats to humanity.

Many countries use DDT against malaria

The World Health Organization (WHO) provides only an exception for indoor DDT use in regions with a significant malaria threat. However, many African countries continue to inject the malaria pesticide on a regular basis. This further fuels the controversy. The chemical itself is only listed as moderately toxic, which means that humans have to experience a fairly large exposure to die from their effects, the researchers explain. Over the decades, however, there have been signs of subtle but serious health effects. Now it should be considered whether autism has to be included in the list of side effects, the researchers emphasize.

What causes autism spectrum disorder??

The study itself can not clarify how DDT could affect brain development. Nor could it be proven that the metabolite of DDT causes autism, especially given the complex nature of the disorder, say the authors of the study. This is characterized by difficulties in sensory processing, communication and socialization and seems to involve various neurological and brain functions. Today, the condition is referred to as autism spectrum disorder to account for the wide range of severity levels and manifestations of its key characteristics. Genetics undoubtedly plays an important role in development, but environmental influences can not be ruled out, the doctors say. It is difficult to pinpoint the multitude of causes behind this complex complaint, and as is often the case, more research is urgently needed, the researchers conclude. (As)