Psychometric Properties of a Brief Health Literacy Instrument (HL-8) Among 18-65-Year-Old Iranians: A Scale Developed for Online Surveys

Background: A short, valid, and reliable instrument is required for the easy assessment of health literacy in online surveys. Objectives: In this study, we investigated the validity and reliability of the Persian version of the 8-item Health Literacy Questionnaire as a brief online survey tool in 18-65-year-old Iranians. Methods: This was a cross-sectional study undertaken in thirty-one provinces of Iran. A total of 2374 Iranian people with age 18 - 65 years participated in this study. To ensure the quality of English-to-Persian translation, the process of forward-backward translation was conducted. The scale's factor structure was assessed using a series of exploratory factor analyses (EFA) and confirmatory factor analyses (CFA). In order to assess reliability, Cronbach's alpha estimation, test-retest reliability, and Spearman correlation coefficients were applied. Results: Most of the participants were male (1610, 67.8%), married (1610, 67.8%), and 31 - 59 years old (1672, 70.4%). Cronbach's alpha coefficients for the factors of finding & evaluating, understanding, decision making, interaction, and the questionnaire as a whole were 0.76, 0.46, 0.75, 0.82, and 0.59, respectively. Test-retest correlation coefficients for these factors and the questionnaire as a whole were 0.85, 0.94, 0.75, 0.82, and 0.86, respectively. Based on CFA, the four-factor structure of the 8-item health literacy (HL) fitted the data well. Conclusions: The validity and reliability of the online version of the Persian 8-item Health Literacy Questionnaire to measure the HL of the public were approved. This short online tool can be helpful for future online survey studies on the health literacy of Persian-language populations at a large scale.