Author Contributions: Dr Tangen 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: Thompson, Paradelo, Crawford.
Acquisition of data: Thompson, Tangen, Lucia, Troyer, Forman, Chin, Canby-Hagino.
Analysis and interpretation of data: Thompson, Tangen, Messing, Forman, Chin, Swanson.
Drafting of the manuscript: Thompson, Tangen, Paradelo, Messing, Swanson, Crawford.
Critical revision of the manuscript for important intellectual content: Thompson, Tangen, Lucia, Troyer, Forman, Chin, Swanson, Canby-Hagino.
Statistical analysis: Tangen.
Administrative, technical, or material support: Thompson, Paradelo, Lucia, Troyer, Messing, Chin.
Study supervision: Thompson, Crawford.
Financial Disclosures: None reported.
Funding/Support: This study was supported in part by the following Public Health Service Cooperative Agreement grants awarded by the National Cancer Institute, Department of Health and Human Services: CA38926, CA32102, CA14028, CA58416, CA58658, CA42777, CA27057, CA46136, CA35431, CA58882, CA12644, CA58861, CA35090, CA37981, CA76429, CA04919, CA76132, CA35119, CA35178, CA35176, CA46282, CA67575, CA45377, CA46113, CA74647, CA35261, CA04920, CA20319, CA76447, CA58723, CA12213, CA22433, and CA46441, and by National Cancer Institute of Canada grant PR-2.
Role of the Sponsor: The National Cancer Institute and the National Cancer Institute of Canada reviewed the design and conduct of the study but had no role in the collection, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.