Environmental Factor, May 2010, National Institute of Environmental Health Sciences
Grantees Grapple with Harmonizing Air Pollution Studies
By Laura Hall
On March 31, investigators with clinical air-chamber facilities in the U.S. and Canada gathered at NIEHS to discuss how to integrate, coordinate, and standardize their air pollution studies to better facilitate regulatory decisions that affect public health. The all-day meeting on "Harmonization of Human Clinical Chamber Air Pollution Exposure Studies" was sponsored by the NIEHS Division of Extramural Research and Training (DERT) and attended by NIEHS grantees and other researchers, as well as NIEHS and U.S. Environmental Protection Agency (EPA) grant administrators.
Jerry Heindel, Ph.D., acting chief of the DERT Cellular, Organs, and Systems Pathobiology Branch (COSPB), opened the meeting by saying that in addition to the traditional practice of "funding the best science by the best scientists," NIEHS needed to work with investigators to develop more coordinated study designs. Harmonization of studies will not only advance the field but also have much greater impact on regulatory decisions, said Heindel.
COSPB Health Science Administrator Sri Nadadur, Ph.D., said he initiated and organized this meeting because previous discussions at grantee meetings recommended harmonization of human clinical air pollution studies, and participants expressed a need for a formal process to initiate this discussion.
There is a need for standardized exposure and end-point response measurement protocols as well as sharing resources and data across different laboratories, Nadadur explained. Harmonization will "aid in cross-study comparisons, novel-effects identification, increased statistical power for genetic susceptibility studies, biomarker validation, and robust clinical translation from chamber air pollution to epidemiology studies."
In her charge to the workshop, NIEHS/NTP Director Linda Birnbaum, Ph.D., pointed out that there were only about 10 laboratories across the U.S. and Canada with "the expertise and facilities to conduct clinical air pollution studies," each with minor variations in protocol that sometimes "make it difficult to harmonize these studies." Birnbaum said, "The beauty of the clinical studies is that it allows us to complete that bridge between animal and epidemiology studies, to identify early biomarkers of responses, and to begin to hone in on some gene-environment interactions."
Birnbaum stressed the need for guidelines for integrating data across laboratories to better make use of ongoing and future studies to address genetic or disease susceptibilities associated with air pollution.
In the first session of the day, University of Southern California Professor Ed Avol explained the translational power of chamber studies to address observations made in epidemiology studies. NIEHS Program Administrator David Balshaw, Ph.D., discussed the new innovative portable sensors and monitors that can characterize the individual's exposures. The developmental research for these devices was funded by the NIH Genes, Environment, and Health Inititive(http://www.genome.gov/19518663) led by NIEHS. Balshaw said that the prototypes are available for validation in chamber studies.
EPA National Program Director for Air Research Dan Costa, Sc.D., told the audience that all studies - encompassing animal to epidemiology research - are used in the regulatory decision-making process. "Population studies will continue to carry a lot of weight, but I think that there is an increasing importance in having these set in a strong foundation of biological plausibility and that is where the chamber studies come in." He added, "Standardization will allow us to do a fairer evaluation scientifically as well as help the regulatory folks in trying to pull all this information together."
By the end of the workshop, the group agreed that there are protocols that would be fairly easy to standardize and that approaching standardization as a tiered system of difficulty, from easy to problematical, would help the harmonization process. They also agreed that there was a need for a consortium to make final decisions on protocols and methodology and to oversee compliance and data sharing.
NIEHS and EPA air pollution grant administrators will work together to increase the coordination of these chamber studies to use available research dollars even more efficiently and effectively.
(Laura Hall is a biologist in the NIEHS Laboratory of Toxicology and Pharmacology, currently on detail as a writer for the Environmental Factor.)
Harmonization - the Doable and the Difficult
In the five moderated panel discussions, the experts discussed pulmonary and cardiovascular effects assessments as well as types of exposure protocols that are made in chamber exposure studies and how they might be standardized. They also discussed the use of genetic markers for genetic and disease susceptibility studies and the advantages of sharing data, tissue, and specimen samples that are collected.
The discussion brought up some challenges to harmonization because of the many variables involved in air chamber studies. Different equipment, equipment settings, and methodology for the same exposure type can create very different test conditions. For instance, particulate matter exposures would have to be carefully characterized in particle numbers and size to achieve harmonization. There are not even standard definitions of asthma and chronic obstructive pulmonary disease (COPD) across the different studies.
Nadadur chaired the organizing committee which was made up of members from NIEHS, EPA, Duke University, University of Rochester, University of Pittsburgh, and the University of Pennsylvania.