For mothers with elevated exposure to the pesticide DDT (75 percentile or greater), there was double the likelihood of their child developing autism with intellectual disability (odds ratio = 2.21, 95% CI = 1.32, 3.69). It should also be noted, DDT has been widely banned in many countries owing to the concerns about its direct and indirect effect on the wildlife.
DDT is one of the first modern synthetic insecticides - an organochlorine that was first synthesized in 1874. It soon proved to be highly effective for insect control in crop and livestock productions, but also around private homes and gardens. Today, DDT is classified as a probable human carcinogen by US and worldwide authorities following animal studies that linked the insecticide to liver tumors.
The study looked for a link between the development of autism and two common environmental chemicals - DDT and PCBs.
"DDT is still persisting in the environment and is detectable in nearly everyone", lead author Dr Alan Brown told IFLScience. Although it was banned more than three decades ago in Finland, people are still exposed to the chemical because it's still in the soil where food is grown. This results in continuous exposure among some populations, and as the chemicals transfer across the placenta, children may also be at risk of prenatal exposure.More news: Ever West Nile Virus case confirmed in Steuben County
A pregnant woman is in a doctor's office in this undated stock photo.
The investigators found the odds of autism with intellectual disability in offspring were increased by greater than twofold for the mother's DDE levels in the top quartile.
"We think of these chemicals in the past tense, relegated to a long-gone era of risky 20th Century toxins", says lead author Alan S. Brown, MD, MPH, professor of Epidemiology at Columbia University's Mailman School of Public Health and of Psychiatry at Columbia University Medical Center.
To get a better sense of direct exposure, Alan Brown, a psychiatrist and epidemiologist at Columbia University in New York City, turned to a biological database in Finland, which has collected and stored blood-serum samples from pregnant women since 1983. Any case of autism is likely due to a number of factors, including genetics and other environmental exposures.More news: Israel’s Shin Bet Interrogate And Threaten Reza Aslan
The study also looked at the risks associated with a class of industrial chemicals called polychlorinated biphenyls (PCBs) that were banned in 1979 in the United States and in 1985 in Europe, but no association with autism was found. Confusingly, a similarly designed 2016 study did find a link to PCBs and failed to identify one with DDT.
The authors concluded that their findings "provide the first biomarker-based evidence that maternal exposure to insecticides is associated with autism among offspring". Second, DDE inhibits androgen receptor binding, an important neurodevelopmental process, while PCBs androgen receptor transcription.
Research in rodents has shown androgen receptors are responsible in disrupting the fetal brain development in males than in females. Some countries in Africa, Asia, and South America need the pesticide for mosquito control in order to reduce the risk of malaria.More news: Watch Don Cheadle Relive the Time Mark Ruffalo Spoiled Infinity War
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