Author Contributions: Dr Tibboel 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. Drs Ceelie and de Wildt contributed equally to this work.
Study concept and design: Ceelie, de Wildt, van Dijk, van den Berg, Knibbe.
Acquisition of data: Ceelie, van den Berg, van den Bosch, de Leeuw, Tibboel.
Analysis and interpretation of data: Ceelie, de Wildt, van Dijk, van den Berg, Duivenvoorden, Mathôt, Knibbe.
Drafting of the manuscript: Ceelie, van Dijk, van den Berg.
Critical revision of the manuscript for important intellectual content: de Wildt, van Dijk, van den Bosch, Duivenvoorden, de Leeuw, Mathôt, Knibbe, Tibboel.
Statistical analysis: Ceelie, van Dijk, Duivenvoorden.
Obtained funding: de Wildt, Knibbe, Tibboel.
Administrative, technical, or material support: Ceelie, van den Berg, van den Bosch, de Leeuw, Mathôt.
Study supervision: de Wildt, van Dijk, Knibbe, Tibboel.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Suppport: This study was supported by ZonMw Priority Medicines for Children grant 40-41500-98.9020.
Role of the Sponsor: ZonMw 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 Ko Hagoort, MA (Erasmus MC–Sophia Children's Hospital), for editorial assistance. Mr Hagoort received no compensation for his contributions.