Author Contributions: Dr Kanatani 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: Kanatani, Yokote, Kuwabara.
Acquisition of data: Fujii, Saijo, Morikawa.
Analysis and interpretation of data: Saito, Takeuchi.
Drafting of the manuscript: Saito, Fujii, Kanatani, Takeuchi.
Critical revision of the manuscript for important intellectual content: Saito, Kanatani, Saijo, Morikawa, Yokote, Kuwabara.
Statistical analysis: Saito.
Obtained funding: Kanatani.
Administrative, technical, or material support: Yokote, Kuwabara.
Study supervision: Kanatani.
All authors commented on early versions of the manuscript and approved the final version.
Financial Disclosures: None reported.
Funding/Support: This study was supported by research funding from the Japan Ministry of Health, Labour and Welfare in fiscal year 2004-2006.
Role of the Sponsor: The study sponsor had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Additional Contributions: We thank Takuya Matsumura, MD, PhD (Department of Internal Medicine, Self-Defense Forces Hanshin Hospital, Hyogo, Japan), and Tomoo Nagai, MD, PhD (Department of Internal Medicine, Self-Defense Forces Central Hospital, Tokyo, Japan), for collecting clinical data and Isao Arita, MD (Agency for Cooperation in International Health [emeritus], Kumamoto, Japan), and J. Michael Lane, MD, MPH (Emory University School of Medicine [emeritus], Atlanta, Georgia), for useful comments and critical reading of an early draft of the manuscript. None of these individuals received any extra compensation for their contributions.
This article was corrected online for typographical errors on 3/10/2009.