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7 October 2002

New Study Finds Exposure to PCBs, Dioxins before Birth Changes Play Behaviors Years Later

Study Released Today in Environmental Health Perspectives Finds Exposed Boys Engage in “Less Masculine” Play; Girls “More Masculine”

[RESEARCH TRIANGLE PARK, NC] A new study published today in the science journal Environmental Health Perspectives found that prenatal exposure to polychlorinated biphenyls (PCBs) and dioxins can influence play behaviors that reflect gender differences. The Dutch study has been tracking various impacts of exposure to these toxicants on a group of children since 1990.
In the latest leg of the study, 189 children with an average age of 7.5 years were evaluated using the Pre-School Activities Inventory, a questionnaire that asks parents 24 questions about how their children prefer to play, including types of toys, activities, and interests.
“Higher prenatal exposure to PCBs was associated with less masculinized play behavior in boys and more masculinized play behavior in girls. In boys as well as in girls, higher prenatal dioxin levels were associated with more feminized play behavior,” the study’s authors wrote. “We therefore suggest that these results may indicate behavioral effects of steroid hormone imbalances early in development related to prenatal exposure to PCBs and dioxins, their metabolites, and/or related compounds.”
The children were evaluated based on their parents’ answers to the questions on the inventory. Representative questions include whether a child prefers playing with tools versus playing with dolls, taking care of babies versus climbing, and avoiding dirt versus taking risks. These data were then cross-referenced with data on each child’s exposure to 4 environmentally important PCBs and 17 dioxins in the umbilical cord blood and the mother’s blood and breast milk. The researchers also evaluated which children were breastfed and which children were formula-fed.
Importantly, breastfeeding was not associated with behavioral changes, suggesting that PCBs and dioxins probably disrupt hormones related to childhood play behavior early in fetal development.
This is the first human behavioral study to show the effects of PCB and dioxin exposure on behavior that reflects marked gender differences, according to the authors. Gender-specific effects of background prenatal studies have not previously been reported in human PCB studies. The authors plan to continue to evaluate the study participants to assess potential implications on later development.
The study team was headed by Hestien J. I. Vreugdenhil of Erasmus University and Sophia Children's Hospital of Rotterdam, The Netherlands.
EHP is the journal of the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. More information is available online at http://www.ehponline.org.

Editor’s note: A full copy of the report is available here http://ehpnet1.niehs.nih.gov/docs/2002/110pA593-A598vreugdenhil/abstract.html or by fax or e-mail (PDF format) to working media at no charge. Contact using phone number listed or e-mail adams6@niehs.nih.gov.