By (July 1, 2008)

Study: Exposure to PCBs Reduces Thyroid Function in Children

ALBANY, N.Y. -- Adolescents exposed to polychlorinated biphenyls (PCBs) demonstrate reduced thyroid function, according to a new report by researchers at the University at Albany-SUNY's Center for the Elimination of Minority Health Disparities (CEMHD). Thyroid hormones are essential for regulating metabolism and normal growth and brain development. They also promote normal cardiovascular, reproductive and nervous system functioning. The study, published in the June 2008 issue of Environmental Health Perspectives, was funded by the National Institute of Environmental Health. Findings reveal that chronic exposure to PCBs directly correlates to reduced thyroid function among adolescents in the Akwesasne Mohawk Nation who had not been breast-fed as infants. PCBs added through breast-feeding may not contribute to reduced thyroid functioning in adolescence.

The Akwesasne Mohawk Nation is located along the St. Lawrence River near several industrial complexes. A National Priority Superfund site and two New York State Superfund Sities are located immediately upstream. In the 1990s, several local animal species were found to have levels of PCBs above human consumption tolerance limits set by the U.S. Food and Drug Administration.

The study focused on adolescents who were exposed to PCBs in both prenatal and postnatal life. The findings also indicate that prenatal exposure to PCBs appear to have a direct impact on thyroid function later in life.

"The work shows that PCBs at levels common in many Americans are related to hormones from the thyroid gland that affect some of the most important systems in the body," said Lawrence Schell, director of CEMHD and lead author of the report.

Among the findings:

• Currently, PCB levels of adolescents at Akwesasne are comparable to those of many populations in the U.S. and Canada and so the results pertain to most people in the U.S.
• Adolescents who had been breast fed as infants still had higher levels of PCBs and other persistent organic pollutants some 10 to 16 years later.
• Breast feeding transfers PCBs and other fat soluable pollutants to the infant, but the higher levels in breastfed adolescents at Akwesasne did not correlate with thyroid hormones.

As an NIH EXPORT (Excellence in Partnerships for Community Outreach, Research on Health Disparities and Training) center, CEMHD works to identify health problems and seeks ways to reduce and eventually eliminate minority health inequities by building the University�s health disparities research capacity and by strengthening community partners� ability to collaborate on research and intervention programs.
 
Under the direction of Schell, professor of anthropology and epidemiology at the University at Albany, CEMHD seeks to make a significant difference in the health of communities by facilitating university-community partnerships to determine local causes of health disparities and then to determine the best, most community-relevant solutions.