Pollutants alter play: another way PCBs affect children. (Science Selections).

A prospective Dutch study that has tracked various health consequences of perinatal exposure to polychlorinated biphenyls (PCBs) and dioxins since 1990 continues to offer new insights into children's health [EHP 110:A593-A598]. The latest assessment by the team, headed by Hestien J. I. Vreugdenhil of Erasmus University Rotterdam and Sophia Children's Hospital, finds that prenatal exposure to these pollutants can influence play behaviors that reflect sex differences.

In this latest stage of the study, 189 children, average age 7.5 years, were evaluated using the Pre-School Activities Inventory, a questionnaire asking parents about their children's play behaviors. The inventory consists of 24 questions that distinguish play behavior between the sexes by focusing on three key aspects of play--type of toys, activities, and child characteristics. 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. Three scales are derived from the inventory: a feminine scale, a masculine scale, and a composite scale integrating both masculine and feminine behaviors.

Each child's perinatal exposure to 4 environmentally important PCBs was estimated from levels of the pollutants in the mother's blood, umbilical cord blood, and breast milk. Breast milk assessments also measured 17 dioxins. About half the children were breastfed for at least six weeks, which increased their exposure to the pollutants, because these pollutants are passed through breastmilk. The other half were fed formula containing no PCBs and dioxins from birth.

Boys with higher prenatal exposure to PCBs scored significantly lower on the masculine scale of play behavior, whereas girls with higher prenatal exposure to PCBs scored higher on the masculine scale. Prenatal exposure to dioxins was associated with higher scores on the feminine scale of play behavior in both boys and girls. Breastfeeding was not associated with behavioral changes, suggesting that PCBs and dioxins probably disrupt hormones related to childhood play behavior early in fetal development. However, the children's levels of steroid hormones were not measured at birth. At some later time in the study, the children will be re-evaluated to observe their sex-related behavioral development.

The authors propose that the alterations in play behavior may be due to steroid hormone imbalances caused early in development, but just how PCBs and dioxins influence steroid hormones remains unknown. The authors recommend following up with this cohort to assess potential implications of these results on later development.