Slovenian six-item health literacy tool reliable, but youth results vary

A six-item health literacy questionnaire showed satisfactory internal consistency in a Slovenian population of 3,360 youth, adults and older adults, but its structural fit and predictive associations were not equally consistent across age groups. Researchers evaluating the European Health Literacy Survey Questionnaire short-short form, HLS-EU-Q6, found that the instrument was reliable and practical for screening, particularly among adults and older adults, while its construct and predictive validity among youth warrant further age-sensitive refinement. The study used data from the Health Literacy of Adults in Slovenia survey, known as HLS-SI19.

Its population included 3,360 participants divided into three age groups: youth aged 18–30 years, adults aged 31–64 years and older adults aged 65 years or above. The researchers assessed construct validity with confirmatory factor analysis and Item Response Theory using Samejima’s Graded Response Model. They also used correlations and hierarchical regression analyses to examine discriminant, concurrent, concurrent-predictive and criterion-related predictive validity, alongside internal reliability.

This was a psychometric validation study, not an intervention or trial of a health-literacy program. A single-factor structure fit the data well among older adults, but the fit was weaker for youth, adults and the full sample. Item-response modelling indicated satisfactory item discrimination and measurement precision, although four of the six items showed age-related differential item functioning.

That pattern indicated partial measurement invariance: some questionnaire items may not function identically at different levels of underlying health literacy across the three age groups. Despite this qualification, internal consistency was satisfactory in every group, with Cronbach’s alpha ranging from 0.76 to 0.84. The results support the HLS-EU-Q6 as a reliable brief instrument, while also showing that measurement properties should not be assumed to be identical for younger and older respondents.

The questionnaire’s associations with other measures were also favourable. HLS-EU-Q6 scores were distinct from measures of communicative and navigational health literacy, supporting discriminant validity. Concurrent validity with the longer, 47-item HLS-EU-Q47 was supported across all three age groups, with a reported correlation of 0.892.

Predictive validity differed more clearly by age. Among adults and older adults, higher health literacy scores were associated with more favourable self-rated health and attitudes toward vaccination. Among youth, health literacy scores predicted only self-rated health and did not show the vaccination-attitude association reported in the two older groups.

These are modelled predictive associations rather than evidence that health literacy causes better health or vaccination attitudes. Overall, the findings identify the Slovenian HLS-EU-Q6 as a practical screening tool with especially consistent performance among adults and older adults, but they also point to a need for further age-sensitive refinement before its results are treated as fully interchangeable across the lifespan.

Subject of Research: Psychometric validation of the HLS-EU-Q6 among Slovenian youth, adults and older adults

Article Title: Psychometric properties of the European health literacy survey questionnaire short-short form (HLS-EU-Q6) among Slovenian youth, adults, and older adults

Article References: Kirbiš, A., Branilović, S., & Lamot, M. (2026). Psychometric properties of the European health literacy survey questionnaire short-short form (HLS-EU-Q6) among Slovenian youth, adults, and older adults. BMC Public Health. https://doi.org/10.1186/s12889-026-28926-5

Image Credits: AI Generated

DOI: 10.1186/s12889-026-28926-5

Keywords: health literacy, HLS-EU-Q6, Slovenia, questionnaire validation, psychometrics, measurement invariance, youth health, older adults, self-rated health, vaccination attitudes, Psychometric, properties