Exposure to insecticides may increase behavioural problems in kids

Children exposed to a widely used group of insecticides may be at increased risk of behavioural problems. According to a new study published online in the journal ‘Occupational and Environmental Medicine’, the insecticides, pyrethroids, which are used on crops can also be found in some mosquito repellents and in products used to treat head lice, scabies and fleas.

The French researchers behind the study said like many types of insecticides, pyrethroids work by damaging nerves, and concerns have recently been raised about their possible effects on children who have been exposed to the products.

A pyrethroid is an organic compound similar to the natural pyrethrins produced by the flowers of Pyrethroids, which now constitute the majority of commercial household insecticides In the concentrations used in such products, they may also have insect repellent properties and are generally harmless to human beings in low doses but can harm sensitive individuals however they are known to be toxic to aquatic organisms including fish.

They are usually broken apart by sunlight and the atmosphere in one or two days, however when associated with sediment they can persist for some time and contribute to toxicity in the surrounding watersheds. However, the new study can’t prove cause-and-effect. Acording to one child psychiatrist, it does raise troubling questions –

“The pesticide class studied are considered ‘safe’ pesticides and this study is cause for concern as to how safe it really is,” said Dr. Matthew Lorber, who reviewed the new findings.

The new study was led by Jean-Francois Viel of the University Hospital in Rennes, France. His team measured hundreds of pregnant women’s exposure to pyrethroids, as well as their children’s exposure, by assessing levels of pyrethroid metabolites in their urine.At age six, the children underwent behavioural assessments.

Viel’s team found a link between pyrethroids and behavioral problems in the children. Specifically, higher levels of a certain pyrethroidlinked chemical in the urine of pregnant women was associated with an increased risk of internalising behaviours — for example, an inability to share problems and ask for help — in their children.

The presence of one such chemical in children’s urine was also associated with an increased risk of externalising disorders — defiant and disruptive behaviours. And another pyrethroid-linked chemical was associated with a lower risk of externalising disorders, the researchers said.

Overall, children with the highest levels of pyrethroid metabolites in their urine were about three times more likely to have abnormal behaviour, the French study found. Pyrethroids may trigger behavioural problems by affecting neurochemical signaling in the brain, the study authors suggested.

“The current study suggests that exposure to certain pyrethroids at the low environmental doses encountered by the general public may be associated with behavioral disorders in children,” Viel’s group wrote. For his part, Lorber called the findings “concerning, because the amounts determined to be ‘low exposure’ are consistent with what children are typically exposed to in the environment.”

Dr. Andrew Adesman is chief of developmental and behavioural pediatrics at Cohen Children’s Medical Center in New Hyde Park in New York. He agreed with Lorber that the findings suggest that pyrethroids “may not be as safe as we would like when it comes to young children.” According to Adesman: “Common sense suggests that pregnant women should minimise their exposure to insecticides and other toxins, as well as other industrial chemicals