Introduction:

Children’s Health and Air Pollution Study-San Joaquin Valley (CHAPS-SJV) is part of the Children’s Environmental Health Center network funded jointly by the National Institute of Environmental Health Sciences (NIEHS) and the U.S. Environmental Protection Agency (EPA).  Formally, CHAPS-SJV is what is know as a “pre-center”—that is, it is a 3-year grant to do the preliminary research and pilot studies necessary to  develop an application for a full center. This center would then be funded for five years to evaluate the hypothesis and implement the study designs developed in the pre-center period. 

CHAPS-SJV is a collaborative effort of researchers from the School of Public Health at University of California, Berkeley, Stanford Medical School and Sonoma Technology, Inc, an organization that is well-known for its expertise in measuring air pollution.  Many of the researchers on this project have been working on FACES (Fresno Asthmatic Children’s Environment Study) since 2000.  CHAPS-SJV is intended to build on the work of FACES and to expand the scope of the research.

Focus on the San Joaquin Valley is highly relevant for several reasons. SJV has one of the fastest growing populations in California, many areas in the Valley have air pollution levels that exceed Federal and California standards for clean air, and areas such as Fresno have disproportionately high numbers of children with asthma compared to the rest of California and  the nation.

Goals:

The overall goal of CHAP-SJV is to study the effects of in utero (fetal) and childhood exposure to outdoor air pollutants and bioaerosols (pollens, fungi and bacterial products) on:

  • Birth outcomes (low birth weight, small for gestational age, prematurity, congenital birth defects)
  • Specialized cells in the body called regulatory T-cells (T-reg) function, which are needed for a normal pregnancy and to control allergic responses that are associated with asthma and other allergic diseases such as hayfever.

These findings will be used to examine how adverse birth outcomes and disturbances to T-reg function help to explain the high frequency of asthma in some parts of the San Joaquin Valley.

To achieve its goals and to develop a larger center, CHAP-SJV has designed 4 projects

  • Project 1:  What neighborhood-level and social characteristics influence women’s susceptibility to outdoor air pollution during pregnancy?. Are there characteristics that exacerbate air pollution’s effects on adverse pregnancy outcomes such as low birth weight and prematurity?
  • Project 2:  Does exposure to outdoor air pollution during critical periods of fetal development increase the chance of structural birth defects?
  • Project 3:  Are the reported associations between outdoor air pollution and asthma onset and exacerbations of asthma the result of pollutant damage to regulatory T-cells (T-reg)?
  • Project 4:  What are some ways to keep people who live in the Valley informed about the work of CHAPS-SJV and to hear about people’s concerns and interests around air pollution and health?

The first three projects depend on refined measures of air pollution exposure that already are available for Fresno through the FACES study and will be developed for Bakersfield as part of CHAPS-SJV.

How will each project work:

Project 1 will use birth certificate records kept by the State of California for Fresno Kern, San Joaquin and Stanislaus counties for the year 2006.  The records already have been linked to the residences at which the mothers lived when their children were born.  Exposure to outdoor air pollution at these residence has been estimated through another study funded by NIEHS (Study of Air Pollution, Genetics and Early Life Events ( SAGE)).  We will define each mother’s neighborhood during pregnant based on new methods developed by one of the researchers and describe the neighborhood by features such as the percentage of people who live below the Federal poverty level, the number and types of crime, the presence of stores that are licensed to sell alcoholic beverages, walkability, retail availability and nearness to major freeways or polluting businesses.  The social, demographic, and environmental characteristics will be obtained from census data and other existing public data registries and sources. We then will compare how differences in each mother’s neighborhood and her air pollution exposures influence adverse birth outcomes.

Project 2 will use information that is collected in California as part of the largest study on birth defects ever conducted in the US (National Birth Defects Prevention Study).  Detailed information collected as part of that study will be used to explore whether mothers who lived in selected areas of the SJV were more likely to have babies born with birth defects based on air pollution levels.  As part of CHAPS-SJV, a special network to measure chemicals in air pollution that have been associated with adverse birth outcomes will be measured in the summer and winter over 2 years.  The exposure of the mothers during their pregnancies will be estimated as was done for Project 1 and neighborhood features also will be determined as for Project 1.

Project 3 is going to enroll 400 7th grade children (200 with asthma and 200 without asthma) from all of the middle schools in Fresno.  All of these children will have participated in “Fresno Kicks Asthma”, which is part of a study funded by the Centers for Disease Control and Prevention (CDC) to learn more about how the environment affects human health.  Letters will be sent through the schools to the parents to invite them to participate in this project.  Parents and children who volunteer to participate will be invited to come to the CHAPS-SJV field office in Fresno.  At the field office, parents and children will answer questions about the health of each child and the child will have a lung function test (called spirometry) and be checked for allergies.  Small blood samples will be collected to measure T-reg cells function.  Each child’s exposure to outdoor air pollution will be determined based on home and school addresses.  We will contrast how air pollution affects T-reg cells function in the children with and without asthma to see whether in children with asthma have cells that are especially sensitive to damaging effects of air pollution.

Why it is the CHAPS-SJV study important to do?

There is still a great deal that we do not know about how and to what extent air pollution can damage the health of people.  More information is needed to find out if air pollution really does increases the changes of having a low birth-weight or premature baby.  Almost nothing is known about whether air pollution increases the risk of birth defects, and, if so, what kinds of defects and among what subgroups of women.  Together, these projects will provide important information on just how air pollution could do damage that can affect pregnancies and subsequently cause asthma.  This type of scientific information is very important to agencies such as the California Air Resources Board and the EPA who have the responsibility to make regulations that assure the safest levels of air pollution possible in our modern society.