How DDT Relates to Autism?

Recently a study was conducted in Finland concerning Autism. Autism is a serious developmental disorder that impairs the ability to communicate and interact. The study was conducted on over 1 million women wherein it was found that increased levels of metabolite of the banned insecticide DDT in the blood of pregnant women have a relation with increased risk for autism in the offspring.

This study is an initiative that was taken up in collaboration with investigators at the University of Turku and the National Institute of Health and Welfare in Finland and the first ever study that connects an insecticide with risk for autism using maternal biomarkers of exposure. During the research the team took maternal blood during early pregnancy and examined it for DDE, a metabolite of DDT, and PCBs, another class of environmental pollutants. The results revealed that mothers in whose blood the levels of DDE were high, their offsprings had odds of autism and intellectual disability. On the other hand, they found absolutely no relation between maternal PCBs and autism. The question arises that when DDT and PCB’s were banned in US and Finland then how could the traces of these insecticides be present in the blood of the offsprings? The research later found that these chemicals persist in the food chain because their breakdown happens at a very slow rate. Resultantly, these chemicals transfer across the placenta to the offspring in concentrations greater than those seen in the mother's blood. To conclude, the researchers offer two reasons for their observation that maternal exposure to DDE was related to autism while maternal PCB exposure was not in any way. First, maternal DDE is related with low birthweight, a well-replicated risk factor for autism. In contrast, maternal PCB exposure has not been related to low birthweight. Second, they point to androgen receptor binding, which is a process important to neurodevelopment. A similar study in rats found DDE inhibits androgen receptor binding, an outcome also seen in a rat model of autism. In contrast, PCBs increase androgen receptor transcription.

By: Anuja Arora

Content:  https://www.sciencedaily.com/releases/2018/08/180816081500.htm