Associations of number of teeth with medical costs and hospitalization duration in an older Japanese population

Aim Many studies have reported close relationships between oral and systemic health. We explored the association of the number of remaining teeth with medical costs and hospitalization duration in people aged 75 and 80 years. Methods Oral health examinations were carried out at dental clinics in 2014. Medical cost and hospitalization duration data for fiscal year 2015 were obtained from the Mie Prefecture health insurer. We analyzed the data of 4700 individuals who met our inclusion criteria: 2745 75‐year‐olds and 1955 80‐year‐olds. The effects of remaining tooth numbers on medical costs and hospitalization days were analyzed using a generalized linear model with log link adjustment for confounders. Results Total medical costs for all diseases were significantly higher in those with 20–27, 10–19 and 1–9 teeth, and in edentulous older individuals, compared with those with 28 teeth. Outpatient medical costs for diabetes were significantly higher in those with 20–27 and 1–9 teeth. Inpatient medical costs for digestive cancers were significantly higher in those with 10–19 and 1–9 teeth, and in edentulous older individuals. Hospitalization for digestive cancer was significantly longer in those with 20–27, 10–19 and 1–9 teeth, and in edentulous older individuals, than in those with 28 teeth. The number of teeth as a continuous variable was significantly inversely associated with medical costs for cerebrovascular disease and digestive cancer, and hospitalization days for digestive cancer. Conclusion Small numbers of teeth were associated with higher medical costs and longer hospital stays for older Japanese. Geriatr Gerontol Int 2019; 19: 335–341 .