Psychometric validation of the Spanish HLS-EU-Q16 in Ecuador: evidence for health literacy assessment and public health education

Introduction: Health literacy (HL) is a key determinant of individual and public health outcomes, as it influences people's ability to access, understand, and apply health information for informed decision-making. Although the European Health Literacy Survey Questionnaire (HLS-EU-Q16) has been validated in several countries, no psychometric validation had previously been conducted in Ecuador. Methods: This study evaluated the psychometric properties of the Spanish version of the HLS-EU-Q16 in a sample of 612 Ecuadorian adults from the three main regions of the country. Confirmatory factor analysis (CFA) was conducted to examine the factorial structure. Internal consistency was assessed using Cronbach's alpha and McDonald's omega, measurement invariance was tested across sex, age, and area of residence, and known-groups validity was evaluated through group comparisons. Results: /df = 2.37, CFI = 0.990, TLI = 0.988, RMSEA = 0.039, SRMR = 0.049), with all factor loadings exceeding 0.50 and excellent model fit. Strict measurement invariance was confirmed across sex, age, and area of residence. The scale demonstrated excellent internal consistency (α = 0.92; ω = 0.94) and strong reliability across dimensions. Known-groups validity was supported, with higher HL levels observed among participants with postgraduate education, urban residence, and absence of financial hardship or chronic illness. Discussion: These findings confirm that the Spanish HLS-EU-Q16 is a valid, reliable, and invariant instrument for assessing health literacy in Ecuadorian adults. The availability of this tool provides a solid foundation for evidence-based health education, targeted interventions, and public health policies aimed at promoting equity and strengthening health literacy in Ecuador and Latin America.