Background and Objectives: Health literacy is a crucial indicator of health status; making it essential to identify the factors associated with it. Doing so may offer healthcare providers valuable insights for planning appropriate interventions to enhance health literacy. This study aimed at evaluating the sociodemographic factors related to health literacy worldwide. Materials and Methods: This systematic review was conducted according to a five-stage approach including designing a research question, identifying relevant evidence, quality assessment of retrieved evidence, preparing a summary of included evidence, and interpretation of the findings. The preferred reporting items for systematic reviews and meta-analysis guideline (PRISMA) was utilized to locate relevant evidence and produce valuable results. Six national and international scientific databases including SID, Magiran, PubMed, Medline, Scopus, and Google Scholar were assessed applying inclusion criteria such as being a cross-sectional study, having a sample size more than ۵۰۰ people, study on general population and wrote in English/ Persian; and using keywords including health literacy, determinants and factors. Qualified studies were examined through Joanna Briggs Institute checklist for cross-sectional studies and EndNote software was used to screen data.Results: Overall, ۵۷۳۹ records from different databases were obtained. After removing duplicates and screening the articles, ۲۸۳ studies were identified appropriate for full-text assessment. After examination of shortlisted studies, finally ۳۲ articles were included in the qualitative synthesis, of them ۲۷ items were at international level and the remaining were national studies, encompassing a total of ۲۱۷۹۳۳ individuals. On average, ۵۳% of participants at the international level and ۵۹% at national level were identified with inadequate health literacy. Common factors associated with inadequate health literacy were: male gender, older age, low education, unemployment, being single, and living in rural areas, whereas among the national studies factors such as older age, male gender and low education were more frequent. Conclusion: In general, sociodemographic factors such as male gender, older age, low education, unemployment, being single and living in rural areas were commonly linked to inadequate health literacy both at the international and national levels. Therefore, developing proper interventions to improve health literacy targeting high risk groups such as older males, people with low education, unemployed individuals and single people should be addressed.
