JKAOH Journal of Korean Academy of Oral Health J Korean Acad Oral Health 1225-388X 2093-7784 Journal of Korean Academy of Oral Health 10.11149/jkaoh.2016.40.1.43 jkaoh-40-43 Original Article Associations between remaining teeth and salivary flow, activity of daily living, and cognitive impairment among the elderly in a rural area: A pilot study KimEun-Kyong1 LeeSung Kook2 JungYun Sook1 LeeHee-Kyung3 SongKeun-Bae4 ChoiYoun-Hee4 Department of Dental Hygiene, College of Science & Technology, Kyungpook National University, Daegu, Korea Department of Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Korea Departments of Dentistry, Yeungnam University College of Medicine, Daegu, Korea Department of Preventive Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea Corresponding Author: Youn-Hee Choi Department of Preventive Dentistry, School of Dentistry, Kyungpook National University, 2177 Dalgubeol-daero, Jung-gu, Daegu 41940, Korea Tel: +82-53-660-6875 Fax: +82-2-53-425-6025 E-mail: cyh1001@knu.ac.kr 032016 12032016 40 1 43 48 21012016 03032016 11032016 Copyright © 2016 Journal of Korean Academy of Oral Health 2016 This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Objectives

The purpose of this study was to assess the associations between oral health, activity of daily living, and cognitive impairment among elderly people who live at home in a rural area.

 Methods

A total of 183 participants older than 70 years of age were recruited from a public health center in a rural Korean city. Trained examiners conducted questionnaire surveys and at-home oral exams to assess oral health, geriatric function, and cognitive impairment. Oral health was assessed by counting remaining teeth and examining salivary flow. Geriatric function and cognitive impairment were assessed using the Mini-Nutritional Assessment (MNA), the Mini-Mental State Examination for Dementia Screening (MMSE-DS), and an activity of daily living (ADL) questionnaire.

 Results

Mean age (SD) of the participants was 83.77 (5.99) years and 68.9% of them were women. The participants who had a lower number of remaining teeth were significantly older, had severe cognitive impairment, and poor ADL and MNA results. The participants with severe cognitive impairment were significantly older and had fewer remaining teeth and low salivary flow. Simple linear regression analysis showed an association between remaining teeth and cognitive impairment with a P-value of 0.000, which disappeared after adjusting for sex and age or sex, age, denture use, and salivary flow, respectively.

 Conclusions

Possible associations between remaining teeth and salivary flow, activity of daily living, and cognitive impairment were discovered among some elderly people living in a rural area.

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Socio-economic status of participants (N=183)

Variables N (%)
Age
70-79 45 (24.6)
80-89 100 (54.6)
≥90 38 (20.8)
Gender
Male 57 (31.1)
Female 126 (68.9)
Education level
Not schooled 111 (60.7)
Elementary school 57 (31.1)
>Middle school 15 (8.2)
Spouse
Yes 112 (61.2)
No 71 (38.8)
Smoking
Yes 23 (12.6)
No 109 (59.6)
Ex-smoking 51 (27.9)
Drinking
Yes 54 (29.5)
No 88 (48.1)
Ex-drinking 41 (22.4)
Regular exercise
Yes 38 (20.8)
No 145 (79.2)
Regular meal
Yes 171 (93.4)
No 12 (6.6)

General health of participants according to remaining teeth

Variables Remaining teeth
 P-value
Total (N=183) ≤ 3 (n=93) ≥4 (n=90)
Mean±SD N (%) N (%)
Age 7.34±9.22
70-79 13.51±11.05 13 (28.9) 32 (71.1) 0.001*
80-89 5.96±7.79 53 (53.0) 47 (47.0)
≥90 3.68±6.74 27 (29.0) 11 (28.9)
Gender
Male 8.51±10.01 28 (30.1) 29 (32.2) 0.757*
Female 6.82±8.83 65 (69.9) 61 (67.8)
physical ADL (Mean±SD) 11.61±3.56 10.38±1.55 0.002†
Instrumental ADL (Mean±SD) 14.19±6.42 11.59±3.23 0.001†
MNA (Mean±SD) 21.62±4.45 23.25±4.34 0.014†
MMSE-DS (Mean±SD) 20.48±5.94 23.89±4.49 <0.001†

ADL: Activity of Daily Living, MNA: Mini Nutritional Assessment, MMSE-DS: Mini-Mental State Examination for Dementia Screening. *P-value by 

-test,

P-value by student's t-test.

Oral health status of participants according to MMSE-DS

Variables MMSE-DS
 P-value
Total (N=183) ≤22 (n=88) ≥23 (n=95)
Mean±SD N(%) N(%)
Age 22.15±5.53
70-79 25.53±3.33 8 (4.4) 37 (20.2) <0.001*
80-89 22.75±4.57 47 (25.7) 53 (29.0)
≥90 16.55±5.87 33 (18.0) 5 (2.7)
Gender
Male 24.82±4.70 14 (7.7) 43 (23.5) <0.001*
Female 20.94±5.47 74 (40.4) 52 (28.4)
Denture use
No 21.98±5.09 64 (35.0) 79 (43.2) 0.088*
Yes 22.20±5.66 24 (13.1) 16 (8.7)
Saliva flow (ml/min) (Mean±SD) 3.87±1.94 5.48±4.81 0.004†
Remaining teeth (Mean±SD) 4.88±7.72 9.63±9.91 <0.001†

MMSE-DS: Mini-Mental State Examination for Dementia Screening. *P-value by 

-test,

P-value by student’s t-test.

Linear regression analysis of remaining teeth and MMSE-DS

Variables Model 1 Model 2 Model 3
B (SE) P-value B (SE) P-value B (SE) P-value
Remaining teeth .187 (.042) 0.000 .071 (.038) 0.062 .080 (.042) 0.058
Age - ―.442 (.058) 0.000 ―.420 (.061) 0.000
Gender - ―2.950 (.706) 0.000 ―2.893 (.709) 0.000
Denture use ―.542 (.876) 0.537
Saliva flow .115 (.088) 0.190

Model 1: Unadjusted model, Model 2: Age and gender adjusted model, Model 3: Age, gender, denture use and saliva flow adjusted model.