Author Contributions: Dr Talbert 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: Talbert, Blumenschein, Stromberg, Freeman.
Acquisition of data: Talbert, Freeman.
Analysis and interpretation of data: Talbert, Blumenschein, Burke, Stromberg, Freeman.
Drafting of the manuscript: Talbert, Blumenschein, Stromberg, Freeman.
Critical revision of the manuscript for important intellectual content: Talbert, Blumenschein, Burke, Stromberg, Freeman.
Statistical analysis: Talbert, Burke, Stromberg.
Administrative, technical, or material support: Talbert.
Study supervision: Talbert, Stromberg.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs Talbert, Blumenschein, and Stromberg reported being supported by grant UL1RR033173 from the National Center for Research Resources and grant UL1TR000117 from the National Center for Advancing Translational Sciences. Dr Freeman reported receiving past grant support from the National Association of State Controlled Substance Authorities for preparation of a white paper on laws regulating methamphetamine precursors. Dr Burke did not report any disclosures.
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: We thank Yevgeniya Gokun, MS (University of Kentucky Applied Statistical Laboratory), for statistical consultation during the preparation of this research letter. Her analytical services as a statistician are available to all investigators free of charge.