Design of the National Children's Study A Workshop Summary (2013) / Chapter Skim
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2 Environmental Measures
2 Environmental Measures
Pages 5-22
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From page 5... ...
Current plans include, but are not necessarily limited to, collection of the following samples: • Household dust • Blood • Urine • Questionnaires on exposures and the social environment • Placenta and cord blood at birth 5
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From page 6... ...
The NCS emphasizes data collections early in pregnancy and early in child development because the largest knowledge gaps, and perhaps the most critical events, occur during those time periods. Pregnancy data collections are scheduled, if possible prior to about 20 weeks of gestation and once later in pregnancy.
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The table Potential Environmental Exposures of Interest2 lists environmental exposures of potential interest to be measured in all NCS participants (general) and in a subset of participants (selective)
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2. How should the NCS prioritize decisions regarding exposure assessments?
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EPA-NIEHS workshop participants defined an exposure metric to include direct measurements as well as measurements combined with other data via a model that would provide the ability to estimate an exposure. They defined a true exposure metric as one that would indicate biologically relevant exposure during the entire time window of susceptibility.
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From page 10... ...
. Discussion Among Panelists About Measurements and Schedule Perry noted minimizing the use of questionnaires, especially to collect environmental exposures, is important because of the burden associated with questionnaires, although a small number of questions can be used to collect information for specific key exposures that cannot be collected using a biologically relevant exposure metric.
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From page 11... ...
She stated collection of some sort of bulk dust sample is important. She noted in some of her research at NCI, she and her colleagues have compared concentrations of chemicals from a participant's vacuum bag or vacuum canister with a more standardized vacuum approach, the HVS3, with very good correlation between the two methods for a range of chemicals, like pesticides, PCBs, and polycyclic aromatic hydrocarbons (PAHs)
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From page 12... ...
She agreed with Sheldon that the collection of a single blood spot for a newborn and planning how to use it are important, and she also concurred that house dust is a very important biologically relevant matrix of exposure. Perry noted the proposed sequencing chronology of measurements -- possibly first trimester, third trimester, at birth, and then going forward -- looks like a logical and a well-thought-out trajectory of sampling over time.
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These databases may provide a way to get exposure information during critical time windows when samples were not collected. Open Discussion About Measurements and Schedule Naihua Duan (Columbia University)
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Perry noted even though collecting pregnancy and prenatal data is challenging, the data are critically important for generating information about in utero exposure related to new findings about prenatal bases of adult disease. She said one flaw she sees with foregoing prenatal sampling in anticipation of collecting information on the second- or third-born is the fact that individuals who have children with health problems may not go on to conceive and reproduce again.
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From page 15... ...
All have prenatal collections with prenatal blood and urine, but none has prenatal environmental house exposures. The possibility of collecting prenatal exposure environmental information is unique to the potential NCS.
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She reminded the audience that future analytic opportunities are dependent on success in collecting blood samples and cord blood samples. She suggested the use of personal monitoring.
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commented on the availability of personal monitoring devices. He said with NCS funding, his group developed eight different residential air quality monitoring parameters that could be wirelessly downloaded and could detect when a cigarette was lit or gas cooking stove turned on.
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Duan added the technologies are not all entirely new. The EPA has conducted a variety of personal monitoring studies for several decades, including the Total Human Exposure Study.
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Paneth commented one of the questions the panel was asked to address concerned potential public health impact of the outcome and noted some of the conditions that might be related to prenatal exposures are not very frequent in the population. Congenital heart defects, cerebral palsy, and type-1 diabetes, for example, are prevalent at less than 1 percent.
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From page 20... ...
At the same time, there are genetic and epigenetic mechanistic studies that blood in particular is going to afford and that would provide insight into mechanisms without having the critical mass of required cases. McCormick said she is uncomfortable when people talk about neurodevelopment as a specific outcome because neurodevelopment covers a fairly large number of relatively rare conditions.
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Sheldon commented that community-level environmental exposures are important: air pollution, water pollution, and soil. Perry said in environmental exposure assessment, a wealth of information shows that environmental exposures are not uniformly distributed and different subpopulations are affected and exposed in different ways.
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From page 22... ...
22 DESIGN OF THE NATIONAL CHILDREN'S STUDY urban and suburban environments, because the population in suburban areas is more likely to be spread out versus an urban population where people share more exposures. In an urban environment, even though a person is not using a particular product or chemical, a close neighbor may be.
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