Two prominent medical researchers are calling for global restrictions on industrial chemicals to protect children from “a global, silent pandemic” of brain disorders including attention deficit hyperactivity disorder (ADHD) and autism.
The warning came in a review published last week in the Lancet Neurology, the Toronto Star reports. “Our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals that are silently eroding intelligence, disrupting behaviours, truncating future achievements and damaging societies,” the researchers write. Children’s developing brains, in the womb and during childhood, are much more susceptible to harmful toxins than are adult brains, according to co-author Dr. Philippe Grandjean, a professor at the University of Southern Denmark, who also teaches at the Harvard School of Public Health.
Grandjean and co-author Dr. Philip Landrigan call for the creation of an international clearinghouse that would coordinate testing of existing and new chemical compounds. They say manufacturers must shoulder the burden of proving a chemical is low risk before it can be used, according to the Star.
Experts report steady increases in worldwide rates of neurodevelopmental conditions like autism and ADHD, with one in 88 children currently diagnosed with autism, up 600 percent in the past 20 years. The rate of ADHD diagnosis in the U.S. is up by more than 50 percent in the past ten years, the Star reports. While heightened awareness and new diagnostic criteria play a role in the increases, scientists are exploring other explanations as well, including chemical exposure. Autism researchers are looking at the complex interaction of genes and environment, which may trigger the disorder in some children.
In 2006, Grandjean and Landrigan documented five chemicals harmful to brain development, including lead and methyl mercury. Since that review, the number of known “neurotoxicants” has doubled and the two scientists believe there are many unrecognized substances that are doing damage, the Star reports. Action is needed now, Grandjean says, because “we are endangering the brains of the future.”
Dr. Rosanna Weksberg, a specialist in epigenetics at the research institute at Toronto’s Hospital for Sick Children, told the Star that despite limited research on the role of chemical exposure in developmental disorders like autism, “there is enough scientific evidence that there may be a link and that it deserves appropriate in-depth investigation.”