Prenatal Exposure to Phthalates Linked to Behavior Problems in Children
Women who are exposed to high levels of hormone-disrupting substances called phthalates during pregnancy tend to have children who display problem behaviors between the ages of 4 and 9 years. Prenatal exposure to phthalates can be hard to avoid, as these toxins are found in thousands of items ranging from plastics to shampoo, perfumes, cosmetics, nail polish, and coatings on medications.
A new study conducted by researchers at Mount Sinai School of Medicine along with those from Cornell University and the Centers for Disease Control and Prevention (CDC) is the first to examine the impact of prenatal phthalate exposure on the neurobehavioral development of children. The investigators found a significant association between the type of phthalates commonly found in personal care products such as lotions and shampoos and disruptive behaviors in children, including aggressiveness, conduct issues, and difficulties with attention.
Stephanie Engel, PhD, Associate Professor of Preventive Medicine at Mount Sinai and the study’s lead author, noted that “These same behavioral problems are commonly found in children diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD), Oppositional Defiant Disorder, or Conduct Disorder.”
The CDC reports that about 4.5 million children ages 5 to 17 have ever been diagnosed with ADHD, and that 3 to 7 percent of school-aged children have the disorder. Oppositional Defiant Disorder affects from 1 to 16 percent of children and adolescents, according to the American Academy of Child and Adolescent Psychiatry. The most severe psychiatric disorder among children and adolescents, conduct disorder, is believed to affect 1 to 4 percent of young people ages 9 to 17, according to the Substance Abuse and Mental Health Services Administration.
Several studies reported prior to the Mount Sinai research found a link between phthalates and behavioral problems in children. In November 2009, a report published in Biological Psychiatry found a significant association between phthalate levels and ADHD in school-age children. In another study, from the University of Rochester Medical Center, experts found that when concentrations of two phthalates in the prenatal urine of women were elevated, their male offspring were less likely to engage in male-typical behaviors.
In the Mount Sinai study, the investigators analyzed the phthalate metabolite levels in prenatal urine samples of 404 women who were pregnant for the first time. The women were then invited to participate in follow-up interviews when their children were between the ages of 4 and 9. A total of 188 women and their children returned for the follow-up portion of the study.
During the follow-up interviews, the investigators learned that mothers who had higher concentrations of low-molecular weight phthalates consistently reported difficult behaviors in their children, with the most prevalent trends associated with characteristics of ADHD, Oppositional Defiant Disorder, and Conduct Disorder.
Although the government has established regulations that limit the use of certain phthalates in toys and other articles that children may put into their mouths, there are no regulations on the types of phthalates found in everyday products used not only by women but by the entire general population.
The results of this new study highlight the impact that prenatal exposure to phthalates can have on neurobehavioral development in children. Along with the findings of previous studies, which point out the relationship between phthalate exposure and behavior problems in children, it is increasing evident that both mothers and their children need to avoid or strictly limit their exposure to these chemicals.
American Academy of Child and Adolescent Psychiatry
Centers for Disease Control and Prevention
Kim et al. Biological Psychiatry 2009; 66(10): 958
Mount Sinai School of Medicine news release, Jan. 28, 2010
Substance Abuse and Mental Health Services Administration
Swan SH et al. International Journal of Andrology 2009 Nov. 16.