Author Contributions: Dr Bell had full access
to all of the data in the study and takes responsibility for the integrity
of the data and the accuracy of the data analysis.
Study concept and design: Bell, Zeger, Samet,
Acquisition of data: McDermott, Zeger.
Analysis and interpretation of data: Bell,
McDermott, Zeger, Dominici.
Drafting of the manuscript: Bell, Dominici.
Critical revision of the manuscript for important
intellectual content: Bell, McDermott, Zeger, Samet, Dominici.
Statistical analysis: Bell, McDermott, Zeger,
Obtained funding: Zeger, Dominici.
Study supervision: Zeger, Samet, Dominici.
Funding/Support: Funding for Drs Bell, Dominici,
and McDermott was provided by the US Environmental Protection Agency (EPA
3D-6867-NAEX). Funding for Drs Dominici, Samet, and Zeger was also provided
by the National Institute for Environmental Health Sciences (NIEHS; ES012054-01)
and by the NIEHS Center in Urban Environmental Health (P30 ES 03819).
Role of the Sponsors: None of the funding agencies
played any role in the design and conduct of the study; collection, management,
analysis, and interpretation of the data; and preparation, review, or approval
of the manuscript.
Acknowledgment: We thank Roger Peng, PhD, for