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Article History

Received: 1 October 2018

Accepted: 10 June 2019

First Online: 5 July 2019

Ethics approval and consent to participate

: The U.S. National Center for Health Statistics (NCHS) restricts access to vital statistics data when linked to states, counties or municipalities. After an application process detailing our proposed use of restricted-access mortality data, the NCHS approved our study. The Institutional Review Board (IRB) at Utah State University (USU) determined that our investigation did not qualify as human subjects research, as defined by the U.S. Department of Health and Human Services. The USU IRB granted ethics approval for our study on November 1, 2016 (Request for Determination of non-Human Subjects Research, Protocol #7992).

: Not applicable.

: The authors declare that they have no competing interests.