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Childhood behavioural difficulties linked to exposure to insecticides

Exposure to a particular group of synthetic chemicals may be linked to behavioural difficulties in six year olds, say researchers in France. 

Exposure to a particular group of synthetic chemicals may be linked to behavioural difficulties in six year olds, say researchers in France. 


Children with the highest levels of metabolites in their urine were about three
times as likely to display abnormal behaviour. Picture: iStock

Pyrethroids, which are found in a range of products including treatments for head lice, scabies and fleas, work by damaging nerves. 

To see if there was any link between prenatal and childhood exposures and behaviour that might indicate neurodevelopmental damage, the researchers measured levels of five pyrethroid metabolites in the urine samples of 287 women between six and 19 weeks of pregnancy, and then in their six year olds. 

Threefold difference

The mothers filled in questionnaires on socioeconomic factors, lifestyle, their child’s behaviour and various environmental exposures. Psychologists then visited them and their children at home to carry out behavioural assessments. 

The researchers found that children with the highest levels of metabolites in their urine were about three times as likely to display abnormal behaviour. This may be due to pyrethroids altering the neurochemical signalling in the brain, the study authors suggested. 


Viel JF et al (2017) Behavioural disorders in 6-year-old children and pyrethroid insecticide exposure: the PELAGIE mother–child cohort. Occupational & Environmental Medicine. doi:10.1136/oemed-2016-104035 

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