Study concept and design: Hanauer, Zheng, Singer, Davis.
Acquisition of data: Hanauer, Singer, Gebremariam, Davis.
Analysis and interpretation of data: Hanauer, Zheng, Gebremariam, Davis.
Critical revision of the manuscript for important intellectual content: Hanauer, Zheng, Singer, Gebremariam, Davis.
Statistical analysis: Gebremariam, Davis.
Administrative, technical, and material support: Hanauer, Singer, Gebremariam.
Study supervision: Hanauer, Zheng, Davis.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This research was conducted with the support of the C. S. Mott Children’s Hospital National Poll on Children’s Health (http://www.mottnpch.org), sponsored by the Department of Pediatrics and Communicable Diseases at the University of Michigan and the University of Michigan Health System.
Role of the Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.