Structural equation modeling to detect predictors of oral health-related quality of life among Japanese university students: a prospective cohort study

Purpose This prospective cohort study of Japanese university students aimed to identify factors that might affect oral healthrelated quality of life (OHRQoL) and longitudinal relationships over a period of 3 years. Methods Students (n = 487) provided complete data before entering and 3 years later (before university graduation) participated in the present study. Decayed, missing, and filled teeth (DMFT) scores, community periodontal index, ratios (%) of teeth with bleeding on probing, and malocclusion were determined during oral examinations. The questionnaire addressed age, sex, self-rated oral health, oral health behavior, subjective oral symptoms, and OHRQoL determined using the oral health impact profile (OHIP)-14. Associations were analyzed using structural equation modeling (SEM). Results The OHRQoL significantly worsened according to OHIP-14 total score (p = 0.001). The final model in the symptoms of SEM analysis showed that OHRQoL at follow-up positively correlated with OHRQoL at baseline. Self-rated oral health was directly associated with the OHRQoL at baseline (p < 0.05). Conclusions This study determined that OHRQoL at baseline was a direct predictor, and that self-rated oral health were indirect predictors of OHRQoL at follow-up among Japanese university students.