ADHD News & Research

Plastic Softening Phthalates Linked to ADHD in Children Treated in Pediatric Intensive Care Units

Phthalates are prohibited from use in kids’ toys because of toxic effects, but remain in medical devices such as plastic tubes and catheters. A new study finds that children exposed to these chemicals during hospitalization had a higher risk of developing ADHD.

April 28, 2016

Phthalates are a family of chemicals that are used to make rubber-based materials soft and pliable. They are found in vinyl, plastic bottles, shower curtains, raincoats, and are also used to make personal-care products, air fresheners, and shampoos. Physicians have suspected a link between exposure and ADHD for many years. Six types of phthalates are banned for use in children’s toys and children’s child care items because of their toxic effects.

Now, a group of researchers investigated their impact on children treated in a pediatric intensive care unit (PICU) with indwelling medical devices containing phthalates to determine if they contribute to ADHD — a condition that is more common in children previously hospitalized. They found that phthalate exposure explained half of the ADHD in post-PICU patients.

The study, published in the March issue of the journal Intensive Care Medicine, evaluated a sample of 100 healthy children, and 449 children from newborn to 16 years who had been treated in PICU, and were neurocognitively tested within the following four years. In the first cohort of 228 patients, the researchers identified the threshold of di(2-ethylhexyl)phthalate (DEHP) metabolites circulating in the body plasma that was associated with decreased neurocognitive outcomes. DEHP is the most commonly used plastic softener in medical devices. In a second cohort of 221 patients, the researchers validated their findings from the first group.

Children who were treated with indwelling medical devices containing phthalates had plasma DEHP metabolite concentrations 18 times higher than healthy children, far exceeding the harmful threshold of exposure. This level is associated with impaired motor coordination and ADHD. It these effects persisted for the four years the children were observed after exposure.

“We found a clear match between previously hospitalized children’s long-term neurocognitive test results and their individual exposure to the phthalate DEHP during intensive care,” says lead researcher Sören Verstraete, M.D., a Ph.D. student at KU (Katholieke Universiteit) Leuven in Leuven, Belgium.

Journal Reference

1. S. Verstraete, I. Vanhorebeek, A. Covaci, F. Güiza, G. Malarvannan, P. G. Jorens, G. Van den Berghe. Circulating phthalates during critical illness in children are associated with long-term attention deficit: a study of a development and a validation cohort. Intensive Care Medicine, 2016; 43 (3): 379-392.