Ethics approval and consent to participate
All the measures taken in this study were approved by the Ethics Committee of Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran (code no. IR.SBMU.PHNM.1400.104) in agreement with the ethical standards of the 1964 Declaration of Helsinki and its later amendments. Informed consent was obtained from all the participants or legal guardians of the illiterate participants for participation in the study.