Grantee Research Project Results
2010 Progress Report: Exposure to Air Pollutants and Risk of Birth Defects
EPA Grant Number: R834596C002Subproject: this is subproject number 002 , established and managed by the Center Director under grant R834596
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: UC Berkeley/Stanford Children’s Environment Health Center
Center Director: Tager, Ira
Title: Exposure to Air Pollutants and Risk of Birth Defects
Investigators: Tager, Ira , Shaw, Gary M.
Current Investigators: Tager, Ira , Hammond, S. Katharine , Shaw, Gary M. , Padula, Amy
Institution: University of California - Berkeley , Stanford University
EPA Project Officer: Callan, Richard
Project Period: May 7, 2010 through May 6, 2013 (Extended to May 6, 2014)
Project Period Covered by this Report: May 7, 2010 through May 6,2011
RFA: Children's Environmental Health and Disease Prevention Research Centers: Formative Centers (with NIEHS) (2009) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health
Objective:
Birth defects are the leading cause of infant mortality in the US. Our Center's research efforts will enhance scientific understanding of the potential environmental etiologies of birth defects, which will undoubtedly have important implications for risk assessment and prevention of these common, costly, and often deadly outcomes of pregnancy. Specifically in this project, we are conducting a rigorous population-based epidemiologic study to address the following research aim: To determine whether exposures to specific air pollutants and mixtures of air pollutants, during critical periods of fetal organogenesis, are associated with women delivering infants/fetuses with structural birth defects.Progress Summary:
In this project we are using data from the largest case-control study conducted to date in the United States. on birth defects — the National Birth Defects Prevention Study. We limit our inquiries to the California study site, which is being conducted in the San Joaquin Valley — an area with demonstrated poor air quality. This study includes information on 30 birth defect phenotypes.
In this first year, project activities have focused on preparing the data for exposure assessment and for epidemiologic analyses. Addresses were geocoded using the Centrus Software, which combines reference street networks from Tele Atlas and United States Postal Service data. Geocodes were available for 95% of cases and 93% of controls, approximately 3,500 cases and controls.
Ambient air pollution measurements and traffic metrics were assigned to each of the geocoded residences reported by the study subjects during the first and second month of pregnancy. Exposure assignments were made if the geocodes were within the San Joaquin Valley and accounted for at least 75% of the first and second month of pregnancy. The pollutants included: ozone (O3), nitrogen dioxide (NO2), nitrogen oxide (NO), carbon monoxide (CO), particulate matter less than 10 μg/m3 (PM10), and PM less than 2.5 μg/m3 (PM2.5). Daily 24-hour averages for all of the pollutants as well as a daily daytime 8-hour maximum for ozone were then averaged over the first two months of pregnancy.
The principal repository for U.S. ambient air quality data is the U.S. Environmental Protection Agency's Air Quality System (AQS) database (Air Quality System (AQS)). The station-specific daily air quality data were spatially interpolated using inverse distance-squared weighting. The data from up to four air quality measurement stations were included in each interpolation. Due to the regional nature of O3, NO2, PM10, and PM2.5 concentrations, a maximum interpolation radius of 50 km was used. NO and CO were interpolated using a smaller maximum interpolation radius of 25 km since they are directly emitted pollutants with larger spatial gradients. When a residence was located within 5 km of one or more monitoring stations with valid observations, the interpolation was based solely on the nearby values.
The data for gaseous pollutants were measured using Federal Reference Method continuous monitors. Particulate matter data were primarily limited to those collected with FRM samplers and Federal Equivalent Method monitors. The national air monitoring networks began measuring PM2.5 in 1999, therefore births with dates of conception prior to 1999 were not part of the analyses of PM2.5.
Traffic density indicators were calculated to represent the amount of traffic counts within a 300 m radius of the early pregnancy residence. Roadway link-based traffic volumes were derived from Tele-Atlas/Geographic Data Technology (GDT) traffic count data in 2005 using methodologies.
More than 97% of geocoded addresses were assigned exposure metrics. The overall completeness for the exposure assignments is 74% for CO, 84% for NO, 98% for NO2, 98% for PM10, 98% for ozone and 91% for traffic density. Among those born after January 1, 1999, 98% of the participants were assigned an estimate for PM2.5 exposure.
With the completion of the exposure assignments, our initial analyses have targeted three specific birth defect phenotypes that, based on past investigations, appear to be more environmentally-sensitive in their etiologies, namely neural tube defects, oral clefts, and the abdominal wall defect known as gastroschisis. Eligible cases included live births, stillbirths, and pregnancy terminations and were selected from the centers surveillance system based on strict eligibility criteria. Controls included non-malformed live-born infants randomly selected from birth hospitals to represent the population from which the cases arise.
Future Activities:
Our plans and goal have essentially not changed. Many analyses are planned in the coming year.Journal Articles:
No journal articles submitted with this report: View all 10 publications for this subprojectSupplemental Keywords:
congenital abnormalities, pregnancy, RFA, Health, Scientific Discipline, ENVIRONMENTAL MANAGEMENT, HUMAN HEALTH, Biochemistry, Health Effects, Children's Health, Biology, Risk Assessment, asthma, air toxics, prenatal exposure, biological response, measuring childhood exposure, air pollution, assessment of exposure, childhood respiratory disease, children's vulnerablity, harmful environmental agents, developmental disordersRelevant Websites:
Children's Health & Air Pollution Study - San Joaquin Valley Exit
Progress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R834596 UC Berkeley/Stanford Children’s Environment Health Center Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834596C001 Effect of Multi-Level Environmental Exposure on Birth Outcomes
R834596C002 Exposure to Air Pollutants and Risk of Birth Defects
R834596C003 Ambient Pollutant/Bioaerosol Effects on Treg Function
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
4 journal articles for this subproject
Main Center: R834596
50 publications for this center
15 journal articles for this center