National Children’s Study Advisory Committee 7 th Meeting
Thematic Sub-Group Breakout Meeting Summary: Asthma
September 15, 2003
Holiday Inn Select
Chair: P. Barry Ryan, Ph.D., NCSAC Member
Emory University Rollins School of Public Health
Dr. Ryan opened the meeting by stating the task: to raise questions or points to send to various Working Groups to help them clarify their hypotheses related to asthma. He also commented that there was no one present who represented the areas of immunity, infections, and vaccines.
Dr. Ryan noted that the incidence of asthma in early childhood is increasing. Susceptibility factors include:
- Respiratory viral infections
- Beta p
- Psychosocial stress.
Haluk Ozkaynak, Ph.D., M.S., Co-Chair, Exposure to Chemical Agents Working Group, Office of Research and Development, EPA, added that the disease is triggered by multifactorial processes. There are many unknowns, including genetic susceptibility. He added the following factors:
- Chemical exposure
- Biological agents
- Toxics, molds
- Food allergies.
Loretta Jones, M.A., Healthy African American Families, added:
- Social factors
- Environmental diesel fuel.
- Hypotheses should reflect a merging of biomedical and social science, as well as incorporate poverty.
- Behavioral factors should be included.
Specificity of Asthma Study Questions
Grace LeMasters, Ph.D., NCSAC Member, University of Cincinnati College of Medicine, asked for clearer definitions that address the following:
- How is asthma defined?
- At what age or developmental point is wheezing predictive?
- What elements in the future are predicted by a wheezy child?
- How do should asthma be defined at different ages?
James Quackenboss, M.S., ICC Member, Office of Research and Development, EPA, asked for more information about:
- Reactions to cold air
- The age at which respiratory outcomes distinguish children at great risk.
Dr. LeMasters questioned whether the hypotheses are specific enough to be scored. For example, do the hypotheses address the following:
- What are asthma phenotypes and how are they measured at different ages?
- How do you measure airway obstruction in the first 2 years of life?
- Should the hypotheses include measuring:
- indoor exposure to environmental agents such as bioaerosol agents
- environment of tobacco smokers
- exposure to nitrogen dioxide for a specific period
- Should the Study focus on identifying baselines on background levels of agents?
- How do the hypotheses measure the relations between independent and dependent variables?
Pauline Mendola, Ph.D., ICC Member, Office of Research and Development, EPA, explained that the hypotheses were developed from a variety of sources over the past several years. In 2000, a group determined the Study’s focus. Several hypotheses have been developed by various Working Groups. It is possible to go back to the Working Groups and ask for more specificity.
Dr. Ryan asked if current hypotheses are sound and broad-based enough so that details could be added in the future.
Recommendation: All four subtypes in the first hypothesis should receive equal weight.
Size of the Study
Group members discussed the size of the Study, including concerns about having to possibly justify the rationale for such a large sample population.
Ms. Jones noted that in a sample of 10,000, the number of asthmatics is probably 6,500; between 3,000 and 4,000 of those will have no diagnosis. Dr. LeMasters suggested that with a smaller sample size, the Study might only reveal a twofold risk if it examines potential interactions. With a larger sample size, Study researchers should be able to identify trends.
Dr. Ryan agreed that a study of this magnitude is necessary to consider interactions. For example, in the case of multiple pollutants with NO 2 and ozone, all agents co-vary under some circumstances.
Asthma in Urban Populations
Dr. Ryan also commented that city populations had a remarkable increase in the incidence of asthma as a result of pollutants and covariants (for example, allergens and diesel exhaust). He asked how that affected sample size.
Mr. Quackenboss asked how feasible it would be to test drug and exposure measures. Dr. LeMasters asked how exposures of concern would be measured. For example, how will pollutants be measured?
Ms. Jones explained that different parts of a city have different levels of pollutants. A monitoring network already exists that can estimate how much a pollutant penetrates indoors. Indoor pollutants are specific to each household.
Dr. Ryan asked how detailed the Study parameters should be—for example, "record measures hourly" or just "measure ozone."
- Whereas the overall hypotheses are well written, the Working Group should now address more specificity (for example, exposure measures and the effects of asthma on parent and child).
- Conduct a workshop on the diagnosis of asthma.
- Select specific population groups to identify and over sample for risk exposures (for example, bronchial challenge could be limited to those with symptoms).
- Consider having the Working Groups do nested studies and case control studies.
Participants agreed that the hypotheses are solid. Participants urged the Working Group to move on to delineating specifics and priorities:
- What species do we need to measure?
- Within what timeframes?
- At what sensitivity (quantitative assessment)?
- What are expected outcomes?
- What is asthma?
- At what age will incidence/prevalence of asthma be first measured?
- What is the measure?
- How do we test pulmonary function in young children—for example, squeeze test?
- Teleconferences are too limited. Rather, conduct intensive 2-to-3-day inter-Working Group workshops, with agendas centered around the hypotheses.
- Working Groups need to get beyond the shopping-list approach. They need to determine critical elements to test hypotheses, who should be measured, and markers of symtomatologies.
- Include measuring early emergency room visits.
Giving Back to the Community
Participants discussed the benefit of giving something from the Study to the community to use as a basis for environmental change, for example, preventive strategies.
- There should be consideration of what the Study could give back to the community, for example:
- Community-based resources concerning asthma
- Short-term deliverables
- A built-in protocol so that the community is always getting something back
- An educational component
- Information on exposures during pregnancy and food allergies; including early pregnancy exposure to pesticides.
- Feedback to the community should occur annually or every 6 months.
- Educational intervention and assessment need to be linked.
- Consider the possibility of cross-pollination among:
- Gene environment
Structure of Future Meetings
The Study Design Working Group will interact with all other Working Groups. Participants noted that at the Baltimore meeting, attendees were had to be in many places at the same time.
- Working Groups should propose what they need to move to the next step (for example, a literature review).
- Working Groups should make proposals about what they want done before proceeding.
- Working Groups should notify the NCSAC when they need to access the expertise of a member from another Working Group.
- Refrain from arbitrarily assigning individuals to various groups (as was the case for the Baltimore meeting).
- Make better use of outside experts where underused.
Donald R. Mattison, M.D., NCSAC Chair, National Institute of Child Health and Human Development, NIH, DHHS, noted that critical issue areas are:
Mr. Quackenboss suggested that obesity and other groups are essential to the Study. Ms. Jones added a design level, adolescence.
Finalizing Study Hypotheses on Asthma
Although participants agreed that there was a solid set of hypotheses, there was concern about what was needed to test them. Theoretically, six priorities should be identifiable. For example, certain stressors exacerbate asthma. When and how can we measure these stressors?
- The Study should included personal details, such as an indoor/outdoor measures, community experience, and questionnaires; critical agents such as diesel versus indoor cooking sources; and culprit pollutions’ links with asthma.
- Hypotheses need to be very specific about what is to measured, and allow enough time to collect these measurements. For example, should indoor dust sampling occur once a year or should it be seasonal?
- There should be a definitive and cost-effective plan supporting how asthma would be measured.
- Working Groups need biomarkers for early assessment of asthma outcomes. These can be extended to embrace one other component (for example, a community/social piece or another component).
Participants concurred that Working Groups need a definitive timeline for developing a framework for asthma assessment through the lifespan of childhood. The Group formulated the following timeline:
||October 1, 2003|
- Response to Working Group from NCSAC
|October 10, 2003|
||November 15, 2003|
||December 15, 2003|
||January 10, 2004|
||February 1, 2004|
Thematic Sub-Group Members
Chair: P. Barry Ryan, Ph.D., Emory University Rollins School of Public Health
Loretta Jones, M.A., Healthy African American Families
Sarah A. Keim, M.A., National Children’s Study Program Office, NICHD, NIH, DHHS
Grace K. LeMasters, Ph.D., University of Cincinnati
Pauline Mendola, Ph.D., CDC, DHHS
James J. Quackenboss, M.S., EPA
Observers and Other Participants
Arthur M. Bennett, M.E.A., B.E.E.
Rebecca Brown, EPA
Haluk Ozkaynak, Ph.D., M.S., EPA
Donald R. Mattison, M.D., NCSAC Chair, NICHD, NIH, DHHS
Ann Vinup, Learning Disabilities Association of America