Pregnant women exposed to DDT insecticides increase the risk of autism in babies
Pregnant women exposed to DDT insecticides increase the risk of autism in babies August 28, 2018 Source: Chinese Journal of Science A study of blood samples from more than 1 million pregnant women in Finland showed that mothers with high levels of DDT pesticides in their blood during pregnancy are more likely to have autism. The World Health Organization estimates that one in every 160 children worldwide has autism. Any autism case can be caused by many factors, including genetic factors and other environmental factors. The researchers stressed that these findings do not prove that autism is caused by DDT - for decades, many countries have banned the use of DDT due to concerns about wildlife. This is the first time that a correlation study has been conducted using a method for directly measuring the amount of pesticide exposure. Researchers who study the link between the environment and the disease say that, if any, further research is needed to determine the mechanism by which DDT exposure triggers autism. The study was published in the August 16 issue of the American Journal of Psychiatry. The study also looked at mothers' exposure to another chemical called polychlorinated biphenyls (PCBs) and found no association between these substances and autism. This finding has deepened questions about whether or how DDT is associated with autism. In Africa, DDT is sometimes used to control mosquitoes. These pesticides can stay in soil and water for decades and accumulate in plants and animals that eat them. PCBs used to be common in building materials and electronics, and they also accumulate in high concentrations in certain fish. Previous studies have linked DDT and PCB to cancer and suggested that these chemicals may affect early childhood brain development and cognitive abilities. However, most of these studies assume that participants' exposure to these chemicals is based on how they approach the contaminated site. The researchers did not directly measure the amount of this chemical in the blood of pregnant women. To better understand direct contact, Alan Brown, a psychiatrist and epidemiologist at Columbia University in New York City, turned to a biological database in Finland that began collecting and preserving maternal serum samples in 1983. A team of Brown and Finnish researchers compared the child's health record with a cohort study that collected serum samples from more than 1 million women born between 1987 and 2005. They found about 1,300 children diagnosed with autism and compared 778 children (including their mothers) with 778 children and mothers without autism, each child and mother were born. The location, date of birth, gender and place of residence were carefully matched. The researchers analyzed the mother's serum samples and observed the levels of certain chemicals that were produced when the body broke down DDT or PCB. The Brown team found no connection between PCB by-products and autism. But when measuring the levels of by-products of DDT in blood samples, they found that mothers with high concentrations of this chemical, the first 25%, were more likely to have autistic children than mothers with lower DDT concentrations. %. Among mothers with high levels of DDT, the likelihood of giving birth to a child with autism and mental retardation is twice that of those with lower DDT levels. Tracey Woodruff, a reproductive health and environmental expert at the University of California, San Francisco, said the study was "very remarkable." She was very impressed with the quantity and quality of the samples in the Finnish database and felt that the link between DDT and autism was shocking. "This confirms that it is a good idea to disable it." In addition, to Brown's surprise, the study did not find a link between PCB exposure and increased incidence of autism, as in other epidemiological studies. "This result taught me that not only is a toxin associated with autism, it is assumed that each toxin is associated with autism," he said. At present, it is not clear how DDT increases the risk of autism, but Brown proposes two hypotheses. DDT has been shown to cause low birth weight and preterm birth, which is a well-known risk factor for autism. Moreover, DDT can also bind to a protein called the androgen receptor in the body, which allows cells to respond to testosterone and other hormones. Rodent studies have shown that some chemicals that bind to androgen receptors can disrupt fetal brain development, especially for boys, who are more likely to be diagnosed with autism than girls. Brown said his team is working on rodents to validate these hypotheses. Bruce Lanphear, an epidemiologist at Simon Fraser University in Burnaby, Canada, also praised the study and said that the correlation between autism and DDT seems to be at least related to autism and multiple genetic mutations. As strong as sex. However, Brown warns that although there appears to be a link between autism and DDT exposure, even among women with higher DDT levels, the overall risk of developing the disease is low. The research team plans to study other organic chemicals in the Finnish database sample to determine if they will affect the fetus through interaction with DDT. Jonathan Chevrier, an epidemiologist at McGill University in Montreal, Canada, is interested in whether DDT levels are associated with mental retardation in children without autism. He is currently tracking the health of more than 700 children in South Africa, and given that South Africa is still using DDT, this may provide clues to the mechanisms by which pesticides affect the brain. He said that this is a very important issue. "At this moment, basically the entire planet is polluted by DDT." (Lu also compiled) Journal of Chinese Sciences (2018-08-27 3rd Edition International) Toilet Cleaner,Toilet Bowl Cleaner,Toilet Cleaning,Toilet Cleaning Powder Wuxi Keni Daily Cosmetics Co.,Ltd , https://www.wxkenidaily.com