The agent was famously criticised for its environmental impacts in the 1960s, and has since become banned throughout most of the world. Yet a number of countries still use the pesticide, and the decision to ban it worldwide isn’t straight-forward.
A research team led by Columbia University used data collected from Finnish mothers for an earlier prenatal study on autism.
They identified 778 children born between 1987 and 2005 who were diagnosed with autism, matching them with maternal blood samples taken during pregnancy. Another 778 control groups were then selected for comparison.
Blood samples were tested for both the pesticide DDT and the metabolite that it forms as it breaks down in our body – p,p’-dichlorodiphenyl dichloroethylene (p,p’-DDE).
In addition, the research team measured the levels of another group of potentially toxic pollutants called polychlorinated biphenyls (PCBs).
There were no signs of a relationship between autism and PCBs. But they did find a significantly increased risk that a child would be diagnosed with autism if the mother was among the top 25 percent of serum DDE levels.
The child was also twice as likely to have an intellectual disability compared with cases of autism among the lowest 75 percent of DDE levels.
Neither DDT nor PCBs have a sterling reputation as it is. We can thank mid-20th century environmentalism for that.