Accepted for Publication: November 19, 2013.
Published Online: May 12, 2014. doi:10.1001/jamapediatrics.2013.5300.
Study concept and design: Whitehill, Moreno.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Whitehill, Moreno.
Critical revision of the manuscript for important intellectual content: Rivara.
Statistical analysis: Whitehill.
Obtained funding: Rivara, Moreno.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by grant R01DA031580-03 from the National Institutes of Health Common Fund, managed by the Office of the Director/Office of Strategic Coordination, and by grant T32HD057822 from the National Institute of Child Health and Human Development.
Role of the Sponsor: The funding sources 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.
Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Additional Contributions: Mara Stewart, BSN, Lauren Kacvinsky, BS, and the Social Media and Adolescent Health Research Team assisted with data collection and management, and Janessa Graves, PhD, MPH, Alex Quistberg, PhD, MPH, and Jin Wang, PhD, offered suggestions about data analysis. Mss Stewart and Kacvinsky received compensation for their roles; the others did not.