Psychometric properties of the English version of the Oral Health Literacy Adults Questionnaire - OHL-AQ.

Objective: To test the psychometric properties of the Oral Health Literacy Adult Questionnaire (OHL-AQ) in English. The OHL-AQ was designed to test functional oral health literacy in general populations and was initially validated in Iran.

Methods: The instrument was administered to 405 adult subjects (mean age 45 (SD 16) years and 67% female) attending the 2014 Minnesota State Fair. The OHL-AQ is composed of 17 items measuring four conceptual dimensions: reading comprehension, numeracy, listening, and decision-making. Participants selected the best answer for written or verbally administered items and entered answers on an electronic tablet. Item responses for each individual were combined into a summary score (range 0-17) with higher scores indicating better oral health literacy. Score dimensionality, reliability, and validity were investigated.

Results: For dimensionality, both exploratory factor analysis and a parallel analysis yielded evidence for scale unidimensionality. Reliability was sufficient indicated by a Cronbach's alpha ⟩0.74. Validity of scores was supported by "small" and "medium" effect sizes for construct validity. "Small" effect sizes were observed for global oral health self-report, OHIP-5 scores, treatment urgency, and having a regular dentist. "Medium" effect sizes were seen for presence of dentures, number of natural teeth present, and educational level.

Conclusions: Dimensionality, reliability and validity of the English version of the OHL-AQ in a general adult English-speaking population is supported, providing sufficient psychometric properties in an important target population of the instrument.