Environmental connections to public health >>
New studies show heightened toxics risks in newborns
Newborn babies are more intensely exposed than previously documented to contamination by bisphenol A (BPA), a synthetic estrogen and ubiquitous plastic component, according to two new studies published by Environmental Health Perspectives, the journal of the National Institute of Environmental Health Sciences. The studies offer new and serious insights into the harm caused by BPA, an industrial chemical found to disrupt the endocrine system, to diminish brain and neurological activity and to cause permanent damage to the reproductive systems of young lab animals.
In a pioneering December 10, 2008, study entitled "Exposure to Bisphenol A and other Phenols in Neonatal Intensive Care Unit Premature Infants," a team led by Antonia M. Calafat of the U.S. Centers for Disease Control and Prevention tested the urine of 41 premature infants being treated in two Boston-area hospital neonatal intensive care units for the presence of BPA and other plastic chemicals.
The scientists detected BPA in the urine of every infant, with a median level of 28.6 micrograms per liter, nearly 8 times the median level (3.7 micrograms per liter) found by CDC in children 6 to 11 in the general population. The most alarming finding: the infant with the most severe exposure to BPA had a total urinary concentration of 946 micrograms per liter, 256 times greater than levels in older children tested by the CDC.
The preemies' BPA readings are even more striking when compared to other CDC data showing that adults in the general U.S. population have a median BPA urine level of 2.7 micrograms per liter. By that standard, the infants' median BPA level was 10 times that of adults; the child with the highest reading had a body burden 350 times that of the median adult level.
The researchers also measured high levels of parabens, preservatives used in pharmaceuticals and cosmetics, and phthalates, plasticizers, which, like BPA, are known to disrupt the endocrine system
The scientists did not pinpoint exactly how the preemies were exposed to BPA and other chemicals, but they reasoned that BPA may have leached into the children's bodies from plastic tubing, drip feeding bags, respiratory masks and catheters. Some BPA, they said, could have come from plastic baby bottles or formula.
The unprecedented study's results are particularly troubling because they suggest that tubing and other medical devices widely used in hospitals are introducing BPA directly into infants' bloodstreams - the most dangerous route of exposure. The study did not identify specific health problems suffered by the infants exposed to high levels of BPA. However, the scientists wrote: "Our findings suggest that infants may be exposed during critical periods of their development to several potential reproductive and developmental toxicants at levels higher than those reported for the general population....Early life exposures are of great concern with regard to the potential for adverse health consequences throughout the lifespan. Because premature infants in intensive care units are both developmentally and physiologically immature, they are a potential high risk population following exposure to environmental chemicals."
A second ground-breaking study, "Predicting Plasma Concentrations of Bisphenol A in Young Children," published in EHP in November 2008 and authored by Canadian scientists Andrea N. Edginton of the University of Waterloo School of Pharmacy and Len Ritter of the Department of Environmental Biology at the University of Guelph, used a mathematical model to predict that a newborn exposed to the same amount of BPA as an adult, per pound of body weight would have 11 times more of chemical in its bloodstream. The reason: an infant's immature body is less able to detoxify and excrete the chemical, so some ingested BPA lingers longer in the baby's blood.
The researchers estimated that by the age of 3 months, as the baby's body developed and its ability to metabolize the chemical improved, the ratio of BPA in the bloodstream would be reduced to twice that in an adult. But they added that "exposure [to BPA] through food in this age group can be greater than in adults" because of exposures from formula, food and baby bottles. Liquid formula is commonly packaged in cans lined with BPA-based epoxy lacquer (though some varieties are also available in non-BPA plastic containers). Some baby bottles are made with BPA-based polycarbonate plastic, although increasingly consumers are opting for glass or non-BPA plastic.
The study concluded that much is not known about how children are exposed to BPA and how their bodies handle the chemical. The scientists concluded that much more sensitive measures are required to understand how BPA contamination affects children.
Under the Bush administration, FDA leaders have resisted pressures from scientists and health and consumer advocates to order BPA removed from food packaging, including baby formula containers, baby bottles and kid-friendly foods such as canned soup, ravioli and vegetable. Last fall, the FDA Science Board issued a blistering critique of that stance, but the agency insisted that more study was necessary and delayed regulatory action. The agency has initiated a separate review of BPA exposures from medical devices, but so far, no results are in.
These important studies are certain to intensify pressure on FDA officials to take urgent action to protect infants and children.