A new study carried out by the University of Southern Denmark (SDU) and Odense University Hospital suggests there is a greater risk of children aged two to four developing ADHD if their mother is exposed to pesticides during pregnancy.
Spraying agents – such as the insecticide chlorpyrifos and a group of insecticides called pyrethroids – are used on many fruits and vegetables and thereby consumed indirectly in high amounts.
“We see a clear connection between these insecticides in the urine samples of the women and the ADHD symptoms displayed by their children,” Louise Dalsager, a co-author of the study and PhD student at SDU, told DR.
“We tried to take into account other factors that could explain the relationship.”
90 percent of pregnant women affected
The study, which has just been published in the scientific journal ‘Environmental Research’, is based on data from 948 pregnant women and their children.
The women and children are all participants in the Odense Child Cohort, a research project following the kids from the fetal stage until they reach the age of 18.
During pregnancy, the women submitted their urine samples for examination and, when their children were aged between two and four, the families responded to a questionnaire concerning the ADHD symptoms.
The researchers measured the residues of the insecticides in the urine samples and found that a high concentration of pyrethroids or chlorpyrifos tended to correspond with an increased number of ADHD symptoms.
“It was surprising to see that the connection was noticeable, even if the concentrations weren’t particularly high,” said Dalsager.
Switch to organic food, says researcher
In Denmark, pyrethroids are used in agriculture and horticulture to paralyse the nervous system of insects and, hence, residues are often found in fruits and vegetables.
The use of chlorpyrifos is forbidden, but it remains in imported fruits and vegetables, as it is permitted in other countries.
Dalsager advises pregnant women to only eat organic fruit and veg – preferably produced in Denmark.
The study was a collaboration between the Research Unit for Environmental Medicine at SDU, the Research Unit for Child and Young Psychiatry at SDU, Odense University Hospital, and Odense Children’s Cohort.