Each year, about 250,000 babies are born in New York. Shortly after each birth, hospital staff pricks the baby’s heel, capturing and drying several drops of blood on a special filter paper known as a Guthrie card. The blood sample is then sent to the state’s newborn screening program at the Wadsworth Center, where it is screened for 45 different genetic, endocrine or metabolic disorders. The speed of the screening process and confirmatory diagnostic testing allows at-risk infants access to prompt and often life-saving medical care.
Some of the remaining collection cards, which are held under highly secure conditions without any identifying links, are now being utilized in a fully consented biomonitoring study funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The study will examine the link between environmental chemical exposures, childhood development and long-term health outcomes.
Biomonitoring is the direct measurement of natural and synthetic chemicals in a person’s body via blood, urine or breast milk samples. In this study, called Upstate Kids, 3,800 children are enrolled from birth and followed through the age of three. The study is approved by the Department of Health’s Institutional Review Board and is being performed with the full consent of the parents of enrolled children. It is a collaboration of the Wadsworth Center and the Center for Environmental Health within the New York State Department of Health and the State University at Albany, School of Public Health.
How is it possible to use stored collection cards for this purpose? According to Kenneth Aldous, PhD, director of the Environmental Health Sciences Division at Wadsworth, biomonitoring is experiencing a rapid expansion in capability due to “the advancement in computers and analytical instrumentation, which has allowed us to measure samples more quickly, using smaller and smaller volumes of human body fluids.”
It is natural that scientists who study the levels of chemicals in people, tracking the rise and fall of certain toxins through the years, would recognize the value of stored newborn blood samples. Dr. Kurunthachalam Kannan, a scientist at Wadsworth working on this study, noted that, “With the help of the parents, we can link the baby’s weight, head circumference, height, and other demographic information to health outcomes of babies. By gaining permission to extend the study once the children reach adulthood, we may also be able to monitor them over their lifetimes.”
The stumbling block for researchers has been that the dried spots on the cards are very tiny, far beyond what they consider a “smaller volume” sample. Is it even possible to create a sensitive enough assay to allow researchers to use the small volumes contained in these residual collection cards? Wadsworth experts now believe that it is.
Using a technique that involves liquid-liquid extraction and high performance liquid chromatography/tandem mass spectrometry method, Kannan and his colleagues have looked for certain endocrine disrupting environmental chemicals (polybrominated diphenyl ethers [PBDEs], perfluorooctane sulfonate [PFOS], perfluorooctanoic acid [PFOA] and bisphenol A [BPA]) in both whole blood samples and dried blood spots. Although they are still trying to determine how to get an accurate measurement of the sample’s exact volume, the results from the collection cards have been remarkably accurate in comparison to the whole blood samples.
In an interesting quirk of the study, the researchers realized they also needed to understand the specific amount of background chemical contamination present on the card. According to Kannan, it matters how the nurses handle the card at the hospital, how it is packaged and mailed, and even how long it is held during the newborn screening process. To evaluate this ambient contamination, laboratorians used a blank punch, reasoning that this spot (taken from an area of the card without any blood) would experience the same contamination as the dried blood, thus allowing scientists to correct for potential contaminations that happened in the hospital after birth compared to chemical exposure that occurred through the placenta.
The success of this study may open the door for biomonitoring programs to study all kinds of childhood exposure to chemicals. In the past, scientists were only able to make educated guesses on chemical exposure via a complex modeling process. Measuring the chemicals directly in people provides valuable information about the sources of chemical exposure and potential long-term health effects. As further research is done, it may also be possible to test for biomarkers for developmental concerns.
In addition to blood samples drawn at birth, and regular motor and social development updates, this study is also gathering extensive demographic information about maternal age, health and assisted reproductive interventions. Many people have concerns about the effect of IVF on the long-term health of the child and studies like this one may provide some answers. The parents of these children will receive ongoing updates of developmental progress and if any child develops health issues, there will be significant data that may help inform the child’s treatment.
With access to the incredible storehouse of information available from these collection cards from nearly every child in the state, in future approved studies, scientists may be able to look at a broader population for trends in chemical exposure over time. Just as public health programs succeeded in getting lead out of gas and paint, and ultimately out of people’s bodies, these studies will help identify which chemicals are causing problems for human health.
At the heart of it, said Aldous, “What is getting into us through the environment? What other chemicals are already present in newborns and how have they been exposed?” Also, said Kannan, “Why are some people sensitive to a chemical exposure of a small amount, when it takes much more to cause a health problem in the next person?”
