Published Online: March 16, 2007 (doi:10.1001/jama.297.12.1224).
Author Contributions: Dr Harper 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: Harper, Lynch, Davey Smith.
Acquisition of data: Harper.
Analysis and interpretation of data: Harper, Lynch, Burris, Davey Smith.
Drafting of the manuscript: Harper, Lynch, Davey Smith.
Critical revision of the manuscript for important intellectual content: Harper, Lynch, Burris.
Statistical analysis: Harper.
Obtained funding: Lynch, Burris.
Administrative, technical, or material support: Lynch.
Study supervision: Lynch, Davey Smith.
Financial Disclosures: None reported.
Funding/Support: This work was supported in part by the Robert Wood Johnson Foundation's Investigator Awards in Health Policy Research Program (Drs Lynch and Davey Smith and Mr Burris) and by contract 263-MQ-314803 from the National Cancer Institute (Dr Harper).
Role of the Sponsors: The funding sources did not participate in the design and conduct of the study, in the collection, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Disclaimer: The ideas expressed herein are the authors’ own and do not represent the Robert Wood Johnson Foundation.