Validation of a theory-based oral health questionnaires among adolescents

Abstract

Objectives: To develop and validate a questionnaire which comprised the main components of health belief model (HMB) and social cognitive theory (SCT) for oral health in Hong Kong adolescents. Methods: One psychologist and two peadiatric dentists drafted the questionnaires based on main domains of HBM and SCT. Face and content validity were assessed by a panel of psychologists (n=5), dentists (n=5), and adolescents (n=10). The questionnaires were further modified according to the suggestions from the face interview and the final scale were consisted of 49 items which were designed to be understandable for adolescents. 254 adolescents (10-17 years old) were recruited from secondary schools and participated in the reliability and construct validity test. Informed consents from their parents were obtained. Construct validity was analyzed by means of factor analysis with varimax rotation. Internal reliability of each domain of theories was assessed using Cronbach’s alpha. 26 participants (10%) were invited to answer the questionnaire again two weeks later. The data were then subjected to test-retest analysis (Spearman’s r). Ethical approval was obtained (IRB HKU: UW 18-209). Results: Among the 20 members in the panel, 95% reported that the questionnaire was understandable and 92.9% agreed that most items were relevant to the main components of HBM and SCT. Five factors were identified for HBM which explained 65.33% of variance. Three factors were identified for SCT which explained 74.73% of total variance. Cronbach’s alpha was 0.84 for HBM and 0.87 for SCT. Correlation coefficients for test-retest analysis were high for all domains of questions (p＜0.001), with a mean value of 0.72. Conclusions: The final scale included 49 items within which 32 items assessed HBM components and 17 items assessed SCT components. It was a valid and reliable tool for measuring HBM and SCT components of oral health in Hong Kong adolescents.