Validation of Ageism Scale for Dental Students (ASDS) in a Multicultural South and Southeast Asian Context

Global populations are ageing rapidly, especially in Asia. The Ageism Scale for Dental Students (ASDS) was developed in 2018 to assess ageism among dental students. This study aims to validate the ASDS in a multicultural, multi-center Asian context to establish a robust tool for future educational and interventional research in gerodontology education.

The original 27-items ASDS was distributed to dental students from five dental schools in Cambodia, India, Indonesia, Malaysia, and Philippines. Data were randomly split for Exploratory Factor Analysis (EFA; n = 400) and Confirmatory Factor Analysis (CFA; n = 355). Sampling adequacy and Bartlett's test were assessed. EFA employed Oblimin rotation, polychoric correlation matrix and maximum likelihood extraction with iterative item removal. Reliability and internal consistency were evaluated with Cronbach's alpha; convergent and discriminant validity were also examined.

EFA revealed 20-items five-factor structure explaining 55.2% of the variance namely therapeutic nihilism, empathy and advocacy, perceived noncompliance and oral health neglect, perceived clinical burden, and confidence and competence. Cronbach's alpha values ranged from 0.742 to 0.839. CFA of the modified model, with 2 items removed, confirmed the five-factor structure with 2-6 items per factor distribution, and good model fit indices (χ²/DF = 3.717, CFI = 0.968, GFI = 0.993, SRMR = 0.055, RMSEA = 0.088). Four factors demonstrated strong convergent validity (AVE ≥ 0.50), while discriminant validity was supported for all factors (HTMT < 0.85).

The modified 18-item ASDS demonstrated robust reliability and validity across the five Asian countries, confirming its utility as a cross-cultural tool for assessing ageism in dental education and guiding the development of culturally sensitive strategies to prepare students for geriatric care.