Determinants of oral health literacy among adults aged 45 years and older with type 2 diabetes: a cross-sectional comparative study

Oral health literacy (OHL) is important for oral health and self-care among people with diabetes, yet evidence comparing OHL across healthcare settings in Taiwan remains limited. This study compared OHL among adults with type 2 diabetes mellitus (T2DM) recruited from a diabetes education clinic and a general dental clinic in southern Taiwan. A cross-sectional comparative study was conducted between February and December 2024. Adults aged 45 years and older with T2DM were recruited from a diabetes education clinic at a regional teaching hospital and from a community-based general dental clinic. OHL was assessed using the validated Mandarin version of the Oral Health Literacy–Adult Questionnaire (OHL-AQ; score range 0–17). Group differences were examined using Mann–Whitney U tests and chi-square tests, and additional bivariate analyses, including Kruskal–Wallis tests and Spearman’s correlations, were performed to describe OHL across selected characteristics. A total of 187 participants were included (diabetes education clinic: n = 115; dental clinic: n = 72). The overall mean OHL score was 11.37 ± 2.86. Participants recruited from the diabetes education clinic had higher mean OHL scores than those from the dental clinic (12.16 ± 2.45 vs. 10.11 ± 3.04; p < 0.001). Domain-level analyses showed higher scores in reading comprehension, numeracy, and listening comprehension in the diabetes education clinic group (all p ≤ 0.001), whereas the difference in decision-making was not statistically significant (p = 0.06). OHL scores also differed by clinical setting, educational attainment, and employment status. In this sample of adults aged ≥ 45 years with T2DM in southern Taiwan, OHL differed across clinical settings, with higher OHL scores observed among participants recruited from a diabetes education clinic compared with a general dental clinic. Given the cross-sectional design and potential selection bias, findings should be interpreted as associations rather than causal effects. Further multi-center and longitudinal studies are warranted.