Author Contributions: Drs Bare and Rosendaal had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Ms Bezemer and Dr Bare made an equal contribution to the manuscript.
Study concept and design: Bare, Doggen, Reitsma, Rosendaal.
Acquisition of data: Bezemer, Doggen, Arellano, Catanese, Young, Rosendaal.
Analysis and interpretation of data: Bezemer, Bare, Doggen, Arellano, Tong, Rowland, Young, Reitsma, Devlin, Rosendaal.
Drafting of the manuscript: Bezemer, Bare.
Critical revision of the manuscript for important intellectual content: Bezemer, Bare, Doggen, Arellano, Tong, Rowland, Catanese, Young, Reitsma, Devlin, Rosendaal.
Statistical analysis: Bezemer, Arellano, Rowland, Rosendaal.
Obtained funding: Rosendaal.
Administrative, technical, or material support: Bare, Doggen, Arellano, Tong, Catanese, Young, Devlin.
Study supervision: Bare, Doggen, Reitsma, Devlin, Rosendaal.
Financial Disclosures: None reported.
Funding/Support: The Leiden Thrombophilia Study was supported by grant 89.063 from the Netherlands Heart Foundation. The Multiple Environmental and Genetic Assessment of Risk Factors for Venous Thrombosis was supported by grant NHS 98.113 from the Netherlands Heart Foundation, grant RUL 99/1992 from the Dutch Cancer Foundation, and grant 912-03-033| 2003 from the Netherlands Organisation for Scientific Research. Celera reimbursed the Leiden University Medical Center for collecting, providing, and shipping the samples. Ms Bezemer received support for training in genetic epidemiology from a Transatlantic Network for Excellence in Cardiovascular Research grant from Fondation Leducq, Paris, France (LINAT project).
Role of the Sponsor: The funding organizations played no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Previous Presentation: Preliminary results were presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress; July 2007; Geneva, Switzerland.
Additional Contributions: We acknowledge the contributions of the Celera High Throughput Laboratory and Computational Biology group and thank John J. Sninsky, PhD, and Thomas J. White, PhD, both Celera employees for helpful comments on this manuscript. We thank Rob van Eck, BSc, Jeroen van der Meijden, and Petra J. Noordijk all from Leiden University Medical Center for performing factor XI measurements. We also thank Hans L. Vos, PhD, of Leiden University Medical Center for supervision of laboratory analysis and for his expertise in genetic data interpretation. All were compensated as part of their regular duties.