Feasibility and informative value of environmental sample collection in the National Children's Vanguard Study.
BACKGROUND
Birth cohort studies provide the opportunity to advance understanding of the impact of environmental factors on childhood health and development through prospective collection of environmental samples.


METHODS
We evaluated the feasibility and informative value of the environmental sample collection methodology in the initial pilot phase of the National Children's Study, a planned U.S. environmental birth cohort study. Environmental samples were collected from January 2009-September 2010 at up to three home visits: pre-pregnancy (n=306), pregnancy (n=807), and 6-months postnatal (n=117). Collections included air for particulate matter ≤2.5 µm (PM2.5), nitrogen dioxide, ozone, volatile organic compounds (VOCs), and carbonyls; vacuum dust for allergens/endotoxin; water for VOCs, trihalomethanes (THMs), and haloacetic acids (HAAs); and wipe samples for pesticides, semi-volatile organics, and metals. We characterized feasibility using sample collection rates and times and informative value using analyte detection frequencies (DF).


RESULTS
Among the 1230 home visits, environmental sample collection rates were high across all sample types (mean=89%); all samples except the air PM2.5 samples had collection times <30 min. Informative value was low for water VOCs (median DF=0%) and pesticide floor wipes (median DF=5%). Informative value was moderate for air samples (median DF=35%) and high for water THMs and HAAs (median DF=91% and 75%, respectively).


CONCLUSIONS
Though collection of environmental samples was feasible, some samples (e.g., wipe pesticides and water VOCs) yielded limited information. These results can be used in conjunction with other study design considerations, such as target population size and hypotheses of interest, to inform the method selection of future environmental health birth cohort studies.
Westat, 1600 Research Blvd, Rockville, MD, United States. Electronic address: eboyle@nas.edu.
Elizabeth Barksdale
EB
Boyle
Yale University School of Public Health, Department of Environmental Health Sciences, New Haven, CT, United States.
Nicole C
NC
Deziel
South Dakota State University, Ethel Austin Martin Program in Human Nutrition, Brookings, SD, United States.
Bonny L
BL
Specker
University of Utah, Department of Pediatrics, Salt Lake City, United States.
Scott
S
Collingwood
Rutgers University, Environmental & Occupational Health Science Institute (EOHSI), Piscataway, NJ, United States.
Clifford P
CP
Weisel
Westat, 1600 Research Blvd, Rockville, MD, United States.
David J
DJ
Wright
Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, United States.
Michael
M
Dellarco
D015331:Cohort Studies; D004781:Environmental Exposure; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007223:Infant; D018811:Maternal Exposure; D011247:Pregnancy; D013048:Specimen Handling
Air samples; Birth cohort study; National Children's Study; Water samples; Wipe samples