Author Contributions: Drs Bach and Begg had full access to the combined, deidentified data, and take responsibility for the integrity of the data analysis, which they performed.
Study concept and design: Bach, Jett, Pastorino.
Acquisition of data: Jett, Pastorino, Tockman, Swensen.
Analysis and interpretation of data: Bach, Pastorino, Tockman, Swensen, Begg.
Drafting of the manuscript: Bach, Begg.
Critical revision of the manuscript for important intellectual content: Bach, Jett, Pastorino, Tockman, Swensen, Begg.
Statistical analysis: Bach, Pastorino, Begg.
Obtained funding: Bach, Tockman.
Administrative, technical, or material support: Bach, Jett, Tockman.
Study supervision: Bach, Pastorino, Tockman.
Financial Disclosures: None reported.
Funding/Support: The pooling and secondary analysis of data from the 3 study sites, and the death record searches, were supported by institutional funds at the 4 involved institutions, and also by the Steps for Breath fund at Memorial Sloan-Kettering Cancer Center. The original data collection at the 3 sites was supported by the European Institute of Oncology and the Italian Ministry of Health (Istituto Tumori); the National Cancer Institute (grant R01CA79935) (Mayo Clinic study); the Department of Defense (Army Advanced Cancer Detection grant DAMD17-98-1-8659) and the National Cancer Institute (grant UO1CA94973) (Moffitt study).
Role of Sponsors: None of the sponsors played any role in the design and conduct of this study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Acknowledgment: We are indebted to the study participants and study investigators of the Beta Carotene and Retinol Efficacy Trial (CARET) trial and the computed tomography screening studies conducted at the Mayo Clinic, the Moffitt Cancer Center, and the Istituto Tumori, as well as to our many colleagues who offered useful insights during this project, none of whom received compensation for our study. We are also indebted to several individuals who were employed at the study sites: Jacqueline Rehbein and Aaron Bungum at the Mayo Clinic (Rochester, Minn); John Bomba at the Moffitt Cancer Center (Tampa, Fla); and Morgan Hanger at Memorial Sloan-Kettering Cancer Center (New York, NY). We also are grateful to Robert Bilgrad, MA, MPH, at the National Center for Health Statistics (Hyattsville, Md), for his assistance but who was not compensated for his work.