title: Evaluating the validity of self-reported smoking in Mexican adolescents.
abstract: OBJECTIVE
  We aimed to evaluate the validity of the self-reported smoking indicator used in the Global Youth Tobacco Survey (GYTS).
  
  
  METHODS
  43 middle and high-school classrooms from 26 schools were selected from Mexico City and Cuernavaca, Morelos.
  
  
  METHODS
  A total of 1257 students provided both a questionnaire and a urine sample.
  
  
  METHODS
  Sensitivity and specificity of self-reported smoking compared to urinary cotinine. Validity indices were evaluated by subgroups of gender, social acceptability of smoking (ie, smoking parents or friends) and smoking frequency.
  
  
  RESULTS
  Sensitivity and specificity for current smoking were 93.2% and 81.7%, respectively. Validity indices remained stable across gender. Parental smoking status moderated the validity of self-report, which had lower sensitivity in adolescents with non-smoking parents (86.7%) than in adolescents with smoking parents (96.6%). Sensitivity and specificity increased with smoking frequency.
  
  
  CONCLUSIONS
  This first validation study of self-reported current smoking used in the GYTS among Mexican adolescents suggests that self-reported smoking in the past 30 days is a valid and stable indicator of current smoking behaviour. This measure appears suitable for public health research and surveillance.
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: María del Carmen
authors.identifier: http://orcid.org/0000-0002-1116-4743
authors.initials: Mdel C
authors.lastname: Valladolid-López
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: Tonatiuh
authors.initials: T
authors.lastname: Barrientos-Gutiérrez
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: Luz Myriam
authors.initials: LM
authors.lastname: Reynales-Shigematsu
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico Department of Health Promotion, Education and Behavior, University of South Carolina, Columbia, South Carolina, USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Thrasher
authors.affiliation: Mexican Institute of Social Security, Mexico City, Mexico.
authors.forename: Ingris
authors.initials: I
authors.lastname: Peláez-Ballestas
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lazcano-Ponce
authors.affiliation: National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hernández-Ávila
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods*; D015203:Reproducibility of Results; D057566:Self Report; D012907:Smoking / Q000453:epidemiology*; D013334:Students / Q000706:statistics & numerical data*; D014029:Tobacco Use Disorder / Q000453:epidemiology
keywords: sensitivity and specificity; surveys; tobacco smoking