Impact of number of functional teeth on independence of Japanese older adults

Abstract

Aim To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. Methods Participants were community‐dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long‐term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. Results This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow‐up period. Kaplan–Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168–3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. Conclusions The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life‐event. Geriatr Gerontol Int 2022; 22: 1032–1039.

Does maintaining the number of present and functional teeth benefit the longevity of life in older people requiring nursing care?: A prospective cohort study

“…As expected, the results indicated that the number of present and functional teeth were not significant risk factors for mortality in the study population. In contrast, previous studies targeting healthy community-dwelling older adults [4,5,31,32] or those requiring nursing care have indicated a positive association between tooth loss (present and functional teeth) and mortality [33,34]. However, in agreement with our results, Saarela et al suggested that the teeth present were not risk factors for mortality among older adults residing in nursing care facilities, as estimated by Cox regression analysis adjusted for age, sex, comorbidities, and MNA scores [18].…”

“…Subsequently, Kaplan-Meier estimator analysis was performed to calculate the participants' cumulative survival rate by sex (male or female), BI score (<40 or ≥40) [26], BMI (underweight or others), nursing care environment (residential care/home care), food texture (regular/modified), number of present teeth (<10, 10-19, or ≥20) and number of functional teeth (<20 or ≥20) [4,5]. Log-rank tests were used to compare the survival curves.…”

“…This is achieved by maintaining healthy masticatory and swallowing functions along with supporting nutritional well-being[1-3]. Moreover, among community-dwelling older adults, the number of functional teeth has been reported to be a stronger predictor of both total mortality and loss of independence than the number of present teeth [4,5].…”

Dietary inflammatory index and number of functional teeth in middle-aged and older Japanese adults: A cross-sectional study using national survey data

“…The masticatory function of partially or totally edentulous individuals can be recovered to some degree by replacing missing teeth [4,5]. The number of functional teeth, including remaining natural teeth and prosthetically restored missing teeth [6][7][8], is widely used in the field of oral epidemiology as an index of oral health when considering dental prosthetic treatments. Two well-designed, large-scale cohort studies [7,8] reported that a lower number of functional teeth was associated with an increased risk of disability and mortality.The possible underlying mechanisms for the association be-tween a lower number of functional teeth and diminished healthy longevity include inadequate and poor-quality diets induced by poor oral health and function [2,3].…”

“…The number of functional teeth, including remaining natural teeth and prosthetically restored missing teeth [6][7][8], is widely used in the field of oral epidemiology as an index of oral health when considering dental prosthetic treatments. Two well-designed, large-scale cohort studies [7,8] reported that a lower number of functional teeth was associated with an increased risk of disability and mortality.…”