Oral status and homebound status: A 6-year bidirectional exploratory prospective cohort study

Objectives: Little is known about the association between oral status and homebound status, and there is a possibility of a bidirectional relationship between them. In this exploratory prospective cohort study, we examined the association between four oral status measurements and being homebound bidirectionally. Methods: We used 2010–2016 panel data gathered from the Japan Gerontological Evaluation Study. All functionally independent participants aged 65 years or older (n = 26,579) were included in this study. Multiple imputation and Poisson regression were used for analyses. We adjusted for age, sex, education, comorbidity, and depressive symptoms. Results: In the fully adjusted model, the prevalence ratio (PR) of being homebound at follow-up was 1.42 for having <20 remaining teeth, 1.28 for having chewing difficulty, 0.99 for having choking experience, and 0.94 for having dry mouth at baseline. Reversely, being homebound at baseline predicted having chewing difficulty at follow-up (PR = 1.17), while no significant association was demonstrated with having <20 teeth (PR = 1.00), choking experience (PR = 1.06), and dry mouth (PR = 1.02). Conclusion: Chewing difficulty and having <20 remaining teeth predicted homebound status after 6 years. Reversely, homebound status at baseline only predicted having chewing difficulty at follow-up. These findings may help to determine the oral frailty assessment measures for older people.