Development and validation of the Environmental Health Literacy Index: a new tool to assess the environmental health literacy among university students.

Environmental health literacy (EHL) is a rather recent concept that applies health literacy skills to environmental issues. Research in this field is still at the beginning, and there is currently no existing tool in the literature designed to comprehensively assess individual general EHL among university students. The aim of our study is to fill this gap through the validation of the Environmental Health Literacy Index (EHLI) in such a target group. We adapted a previously administered survey, originally completed by 4778 university students from various Italian universities. Starting from the original questionnaire, our methodology involved a three-round item selection process, followed by a comprehensive evaluation of the instrument's psychometric properties. The EHLI consists of 13 Likert-type items, covering three primary domains of health literacy: functional (six items), interactive (three items), and critical (four items). The Cronbach's alpha coefficient is 0.808 for the global scale, while it stands at 0.888 for the functional, 0.795 for the critical, and 0.471 for the interactive components. The area under the receiver operating characteristic curve reached a value of 0.643. Spearman correlation analysis revealed a significant yet slight correlation between EHLI and both functional health literacy score and the extent of pro-environmental behaviors adoption. Our study serves as an important initial step in developing a tool able to evaluate the EHL of university-aged individuals. Further research efforts may improve the questionnaire's validity and completeness, as well as to explore its applicability to different age groups.