Dental Status is Associated With Incident Functional Disability in Community-Dwelling Older Japanese: A Prospective Cohort Study Using Propensity Score Matching.

Takamasa Komiyama,Makoto Watanabe,Ichiro Tsuji,Takashi Ohi,Fumiya Tanji,Yasutake Tomata,Yoshinori Hattori

doi:10.2188/jea.je20180203

Abstract

BackgroundA growing number of epidemiology studies have shown that poor oral health is associated with an increased incidence of functional disability. However, there are few studies in which the confounding bias is adjusted appropriately. In this study, we examined whether dental status is associated with functional disability in elderly Japanese using a 13-year prospective cohort study after elimination of confounding factors with propensity score matching.MethodsParticipants were community-dwelling Japanese aged 70 years or older who lived in the Tsurugaya district of Sendai (n = 838). The number of remaining teeth (over 20 teeth vs 0–19 teeth) was defined as the exposure variable. The outcome was the incidence of functional disability, defined as the first certification of long-term care insurance (LTCI) in Japan. The variables that were used to determine propensity score matching were age, sex, body mass index (BMI), medical history (stroke, hypertension, myocardial infarction, cancer, and diabetes), smoking, alcohol consumption, educational attainment, depression symptoms, cognitive impairment, physical function, social support, and marital status.ResultsAs a result of the propensity score matching, 574 participants were selected. Participants with 0–19 teeth were more likely to develop functional disability than those with 20 or more teeth (hazard ratio 1.33; 95% confidence interval, 1.01–1.75).ConclusionsIn this prospective cohort study targeting community-dwelling older adults in Japan, having less than 20 teeth was confirmed to be an independent risk factor for functional disability even after conducting propensity score matching. This study supports previous publications showing that oral health is associated with functional disability.

Highlights

The increase in the number of older adults and the rise in aging rates have been rapidly progressing all over the world, these phenomena have been more pronounced in Japan than in other countries.[1]
Several studies have demonstrated the relationship between oral health status and incidence of functional disability, which is a major indicator of healthy life expectancy
Some reports have examined the relationship between tooth loss and mortality using propensity scores as a covariate.[13,14]. In this prospective cohort study, we focused on the number of remaining teeth, which is a representative indicator of oral health, and conducted propensity score matching to reduce the influence of confounding bias as much as possible

Summary

Introduction

The increase in the number of older adults and the rise in aging rates have been rapidly progressing all over the world, these phenomena have been more pronounced in Japan than in other countries.[1]. A growing number of epidemiological studies have shown that oral health is associated with systemic diseases, such as dementia and stroke,[3,4] as well as with disability, reflected by a decline in physical functions and an increased incidence of falls.[5,6] several studies have demonstrated the relationship between oral health status and incidence of functional disability, which is a major indicator of healthy life expectancy. In many studies, the influence of confounding bias was not fully considered. A growing number of epidemiology studies have shown that poor oral health is associated with an increased incidence of functional disability. We examined whether dental status is associated with functional disability in elderly Japanese using a 13-year prospective cohort study after elimination of confounding factors with propensity score matching

Methods

Results

Discussion

Conclusion