title: Health Literacy Measure for Adolescents (HELMA): Development and Psychometric Properties.
abstract: BACKGROUND
  Health literacy refers to personal competencies for the access to, understanding of, appraisal of and application of health information in order to make sound decisions in everyday life. The aim of this study was to develop and evaluate the psychometric properties of an instrument for the measurement of health literacy among adolescents (the Health Literacy Measure for Adolescents-HELMA).
  
  
  METHODS
  This study was made up of two phases, qualitative and quantitative, which were carried out in 2012-2014 in Tehran, Iran. In the qualitative part of the study, in-depth interviews with 67 adolescents aged 15-18 were carried out in 4 high schools to generate the initial item pool for the survey. The content validity of the items was then assessed by an expert panel review (n = 13) and face validity was assessed by interviewing adolescents (n = 16). In the quantitative part of the study, in order to describe the psychometric properties of the scale, validity, reliability (internal consistency and test-retest) and factor analysis were assessed.
  
  
  RESULTS
  An item pool made up of 104 items was generated at the qualitative stage. After content validity was considered, this decreased to 47 items. In the quantitative stage, 582 adolescents aged 15-18 participated in the study with a mean age of 16.2 years. 51.2% of participants were females. In principal component factor analysis, 8 factors were loaded, which accounted for 53.37% of the variance observed. Reliability has been approved by α = 0.93 and the test-retest of the scale at two-week intervals indicated an appropriate stability for the scale (ICC = 0.93). The final questionnaire was approved with 44 items split into eight sections. The sections were titled: gain access to, reading, understanding, appraise, use, communication, self-efficacy and numeracy.
  
  
  CONCLUSIONS
  The Health Literacy Measure for Adolescents (HELMA) is a valid and reliable tool for the measurement of the health literacy of adolescents aged 15-18 and can be used to evaluate different levels of functional, interactive, and critical health literacy in adolescents.
authors.affiliation: Department of Public Health, School of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Shahla
authors.initials: S
authors.lastname: Ghanbari
authors.affiliation: Department of Public Health, School of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Ramezankhani
authors.affiliation: Mental Health Research Group, Health Metrics Research Centre, Iranian Institute for Health Sciences Research, ACECR, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Montazeri
authors.affiliation: Department of Epidemiology, School of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Yadollah
authors.initials: Y
authors.lastname: Mehrabi
mesh_terms: D000293:Adolescent; D003710:Demography; D005260:Female; D057220:Health Literacy; D006801:Humans; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results