Article History
Received: 27 January 2018
Accepted: 13 June 2018
First Online: 23 June 2018
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: The study was approved by the Ethics Committee of the Universidad del Valle de Guatemala on July 3, 2000 and the permission to analyze the data was granted by the Ethics Committee of the University of Texas Health Science Center at Houston on August 14, 2015 (permit code HSC-SPH-15-0551). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.