Common Chemicals Linked with Attention Deficit

What are phthalates?
Phthalates (pronounced THAL-ates) are synthetic chemicals used to make plastics soft and flexible. Phthalates are used in hundreds of consumer products and humans are exposed to them daily though air, water, and food. Di(2-ethylhexyl)phthalate (DEHP) is the name for the most common phthalate. It can be found in products made with plastic such as tablecloths, floor tiles, shower curtains, garden hoses, swimming pool liners, raincoats, shoes, and car upholstery. Based on animal studies, the Environmental Protection Agency (EPA) has classified DEHP as a “probable human carcinogen1.” Such studies have shown that DEHP exposure affects development and reproduction.

What is already known about phthalates?
Previous research has shown children with higher levels of DEHP byproducts in their urine have worse inattention and hyperactivity2.  It is also known that children who are critically ill when they are very young have considerable deficits in executive functions, motor coordination, and attention. However, it was previously unknown whether exposure to phthalates in hospitals plays a role in these neurocognitive deficits. In the hospital, DEHP can be found in and can leach from medical devices such as catheters, blood bags, breathing tubes, and feeding tubes.

Recent findings
New research shows that exposure to DEHP in pediatric intensive care units (PICU) is associated with attention deficits in children. Researchers from Belgium measured levels of DEHP byproducts in the blood of 449 children aged 0-16 while they were staying in a pediatric intensive care unit. The majority of the patients were in for heart surgery for congenital heart defects. Four years later, the children’s neurocognitive development was tested and compared to healthy children.

The researchers found that all medical devices and/or their accessories inserted into the body actively leached DEHP. Critically ill children had very high levels of DEHP byproducts throughout their stay in the intensive care unit. In contrast, healthy children had virtually undetectable DEHP byproducts in their blood. Specifically, critically ill children’s blood DEHP levels were 111 times higher upon PICU admission and eight times higher on the last PICU day compared to healthy children.

A high exposure to DEHP was strongly associated with attention deficit and impaired motor coordination four years later. In fact, PICU phthalate exposure explained half of the attention deficit in post-PICU patients.

Shockingly, the researchers noted, “The potentially harmful threshold could be reached even with minimal indwelling instrumentation of the children and thus, with the currently used material, appears unavoidable3.”



1. Environmental Protection Agency (EPA). Bis(2-ethylhexyl) phthalate (DEHP). Technology Transfer Network – Air Toxics Web Site.
2. Kim, B., Cho, S., Kim, Y., Shin, M., Yoo, H., Kim, J., & … Hong, Y. (2009). Phthalates Exposure and Attention-Deficit/Hyperactivity Disorder in School-Age Children. Biological Psychiatry, 66(Autism: Molecular Genetics and Neurodevelopment), 958-963.
3. Verstraete, S., Vanhorebeek, I., Covaci, A., Guiza, F., Malarvannan, G., Jorens, P. G., & Van den Berghe, G. (2016). 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, (3), 379.

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