|Year : 2021 | Volume
| Issue : 4 | Page : 344-349
Comparison of oral health-related quality of life between community-dwelling elderly people with cognitive decline and normal elderly in Japan
Yoshifumi Toyoshita1, Mizuho Sasaki1, Katsuya Kawanishi1, Shuichi Hara2, Hiroko Miura3, Hisashi Koshino1
1 Division of Occlusion and Removable Prosthodontics, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Hokkaido, Japan
2 Department of Speech-Language-Hearing Therapy, Kyushu University of Health and Welfare, Nobeoka, Miyazaki, Japan
3 Division of Disease Control and Molecular Epidemiology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Hokkaido, Japan
|Date of Submission||02-Mar-2021|
|Date of Decision||08-Apr-2021|
|Date of Acceptance||22-Apr-2021|
|Date of Web Publication||19-Aug-2021|
Dr. Yoshifumi Toyoshita
Division of Occlusion and Removable Prosthodontics, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-gun, Tobetsu, Hokkaido.
Source of Support: None, Conflict of Interest: None
Aim: The aim of this article was to survey oral health-related quality of life (OHRQOL) of elderly people and compared that of elderly people with cognitive decline with that of those with no cognitive decline. Materials and Methods: The cognitive function of community-dwelling elderly people (65 years old or more, n = 188) in Japan was measured by Mini-Mental State Examination, and subjects were divided into normal and impaired groups. Oral status was examined and for those wearing dentures, the dentures were assessed by the prosthodontic specialists with clinical techniques and by the subjects themselves with visual analog scale. Masticatory function was assessed by an objective method with a test food and a subjective method with a questionnaire. OHRQOL was measured by General Oral Health Assessment Index (GOHAI). The statistical analysis was carried out using the Mann–Whitney U-test and χ2 test. Results: The number of remaining teeth and masticatory ability in the normal group were significantly higher than that in the impaired group. There are significant differences on the ratio of answers in Q2, Q7, Q9, Q10, and Q11 at GOHAI. The status of dentures by subjective and objective assessment was almost the same in both groups. Conclusion: Elderly people with cognitive decline decrease masticatory function with fewer remaining teeth, and it is revealed that they have trouble in chewing and psychological and oral discomfort caused by oral problems.
Keywords: Cognitive Decline, GOHAI, Masticatory Function
|How to cite this article:|
Toyoshita Y, Sasaki M, Kawanishi K, Hara S, Miura H, Koshino H. Comparison of oral health-related quality of life between community-dwelling elderly people with cognitive decline and normal elderly in Japan. J Int Oral Health 2021;13:344-9
|How to cite this URL:|
Toyoshita Y, Sasaki M, Kawanishi K, Hara S, Miura H, Koshino H. Comparison of oral health-related quality of life between community-dwelling elderly people with cognitive decline and normal elderly in Japan. J Int Oral Health [serial online] 2021 [cited 2022 Jan 29];13:344-9. Available from: https://www.jioh.org/text.asp?2021/13/4/344/324148
| Introduction|| |
According to the survey conducted by Alzheimer’s Disease International, over 50 million people are living with dementia all over the world and it is estimated that the total number of patients in 2035 and 2050 will be 82 million and 152 million, respectively. It is expected that the number of patients will increase in the future. The prevalence of dementia in most areas of the world is 5–7%. From a systematic review of 21 studies, the prevalence rates for dementia in Japan were from 2.9% to 12.5%. By a domestic survey in 2012, 4.6 million patients with dementia were found among elderly people aged 65 or over. As aging rate in Japan had been raised to 28.7% in 2020 and will reach to 40% in 2060, the total number of patients with dementia in Japan is expected to increase coinciding with the world trend.
As we have no radical cure for dementia at the moment, the main treatment for it is the combination of non-pharmacotherapy like rehabilitation and pharmacotherapy to suppress symptoms. Prevention of cognitive decline by elimination of risk factors is consequently placed emphasis as the most important measure for dementia.
Oral function is one of the factors interacting with cognitive function. The number of missing teeth, maximum biting force, posterior teeth contact, and masticatory malfunction raise the incidence of dementia among independent elderly people.,,, From the view of prevention of dementia, investigation of relationship between oral health and cognitive function is of great significance. Oral health-related quality of life (OHRQOL) is utilized for the measurement of subjective oral health. It is useful for maintenance of oral status to survey how elderly people with cognitive decline see their oral health in their daily life and to analyze the characteristics and disposition of their recognition. However, only a few studies have reported OHRQOL of independent elderly people with cognitive decline. In this study, we surveyed OHRQOL of elderly people and compared that of elderly people with cognitive decline with those with no cognitive decline.
| Materials and Methods|| |
All of the Japanese independent elderly people (1550 people) residing in a survey site of Hokkaido, Japan were requested to participate in the survey by mail. The candidates were 65 years old or more. One hundred eighty-eight people who participated had their oral and cognitive status examined and analyzed cross-sectionally.
Measurement of cognitive function
The cognitive function of the subjects was measured by Mini-Mental State Examination (MMSE) in Japanese version. Full score is 30 points, and the range of 27–30 points was classified as “normal,” and the range of 24–26 points was classified as “impaired.” The subjects who got 23 points or less were excluded from the analysis because it is possible that they could not understand correctly what the examiner requested them to do.
Oral and dentures examination
Dentists collected the subjects’ information (e.g. age, sex, and their health) and examined their oral cavity and remaining teeth. When subjects wore dentures, the prosthodontic specialists approved by the Japan Prosthodontic Society examined the dentures. Dentures were checked on the basis of the shape of base, fitness, and wear of artificial teeth and ranked as “excellent,” “average,” and “poor.” The prosthodontic specialists observed shape of base and fitness by silicone materials for checking fit (Fit Checker II, GC, Tokyo, Japan) and wear of artificial teeth by visual examination with depth of fissure and flattening of cusp. As subjective assessment, subjects assessed their dentures with visual analog scale (VAS). VAS consists of 6 scales: namely “satisfaction,” “suitability,” “pain,” “mastication,” “esthetics,” and “speech.” Subjects marked the most applicable point on each scale, considering the right end of each scale as the worst and the left end as the best, and measured the distance from the marked points to the right end. VAS score was calculated as the distance from the marked points to the right end divided by the total scale length by 100.
Masticatory score and masticatory ability
The masticatory score (MS) was measured as a subjective assessment of masticatory function. We asked the subjects whether they can masticate 25 foods that have various textures or not and calculated the MS by the prior method. The masticatory ability was measured as an objective assessment of masticatory function. The subjects masticated 2 g of standardized gummy jelly including glucose (Grucolum, GC, Tokyo, Japan) for 20 s freely, rinsed their mouth with 10 mL of pure water, and spitted all of them. The concentration of glucose in the liquid part was measured by a saccharimeter (Glico Sensor GS-II, GC, Tokyo, Japan).
Measurement of OHRQOL
OHRQOL was measured by GOHAI in Japanese version. The subjects answered 12 questions consisting of three subcategories: physical function (Q1–4), psychosocial impacts (Q6, 7, 9–11), and pain and discomfort (Q5, 8, 12) with “Never,” “Seldom,” “Sometimes,” “Often,” and “Always.” “Never” was scored as 5 points, “Seldom” as 4 points, “Sometimes” as 3 points, “Often” as 2 points, and “Always” as 1 point. The score of each question ranges from 1 to 5, the total score ranges from 12 to 60, the subcategorical score in physical function ranges from 4 to 20, the subcategorical score in pain and discomfort ranges from 3 to 15, and the subcategorical score in psychosocial impacts ranges from 5 to 25. The mean of each question, total score, and subcategorical scores were calculated.
The data were analyzed by SPSS Statistics 22 (IBM, Tokyo, Japan). The Mann–Whitney U-test was used for comparison of the MMSE score, age, the number of remaining teeth, masticatory score, masticatory ability, VAS score, and GOHAI score in the normal and the impaired groups. The χ2 test was used for difference of proportion of gender, prevalence of lifestyle diseases and objective assessment of dentures by the prosthodontic specialists, and ratio of answer in GOHAI in both groups. Statistical significance was defined at P < 0.05.
| Results|| |
The summary of subjects is shown in [Table 1]. The normal group has 92 people and the impaired group has 71 people. Age, the number of remaining teeth, the MMSE score (P<0.01), and masticatory ability (P<0.05) between both groups have significant difference. There is no difference in prevalence of lifestyle diseases in both groups.
Distribution of remaining teeth is shown in [Figure 1]. The ratio of 25 teeth or over in the normal group is considerably higher than that in the impaired group, and the ratio of four teeth or less in the normal group is lower than that in the impaired group conversely. Other parts of the number of teeth are mostly same in both the groups.
|Figure 1: Distribution of remaining teeth. Y-axis shows ratio and X-axis shows the ranges of the number of remaining teeth|
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Mean value and standard deviation of the GOHAI score are shown in [Table 2]. From most of the questions, subcategories, and total score, the mean in the normal group was just a little higher than that in the impaired group, but there is no significant difference between both the groups. The ratio of answers in all questions is shown in [Figure 2]. There are significant differences on the content of answers in Q2 (P=0.019), Q7 (P=0.043), Q9 (P=0.004), Q10 (P=0.045), and Q11 (P=0.014). Compared with the answer of the normal group, the ratio of “Often” or “Sometime” in those questions was higher than that in the impaired group.
|Figure 2: The ratio of answers to GOHAI. *Significant difference at P < 0.05 and †significant difference at P < 0.01|
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The denture wearers were 112 subjects (normal group: n = 56, impaired group: n = 56). Eighty-eight lower and upper dentures in the normal group and 90 dentures in the impaired group were examined. Objective conditions of dentures were almost the same in both the groups [Figure 3]. Subjective assessment had no significant difference in both the groups as well as objective results [Table 3]. The mean of VAS score at “Satisfaction,” “Mastication,” “Esthetics,” and “Speech” in the normal group was higher when compared with the impaired group.
|Figure 3: Objective assessment of the denture by the prosthodontic specialists|
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|Table 3: VAS scores by the subjective assessment of the dentures (mean value±SD)|
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| Discussion|| |
Some of the risk factors for dementia are aging and lifestyle diseases (e.g. hypertension, diabetes, and hyperlipidemia).,, Significant difference was found in the age of both the groups; however, there were no difference in lifestyle diseases. In this study, the subjects were interviewed about the status of their whole body and answered according to their own perception. Generally in Japan, an elderly person has much diseases and takes a lot of medicine, clouded with medical complexities. For that reason, they might not recall or comprehend all of their diseases or body status precisely.
It is reported that the number of remaining teeth and occlusal units supporting masticatory function are related with cognitive decline., Our result that masticatory function and the number of teeth in the normal group were higher than those in the impaired group matches previous studies. There is possibility that oral and cognitive functions are interacted via trigeminal nerve and stimulate each other for the maintenance of functions. To consider the difference of masticatory function, we analyzed the condition of the dentures. The subjective and objective evaluation of the dentures had no difference between both the groups. The difference of masticatory function is expected due to trouble of remaining teeth or just difference of the number of the remaining teeth. Actually, the wider the area of dentate defect gets expanded by loosing teeth, the ability of mastication declines, even though the condition of denture is equivalent.
To screen cognitive function, MMSE is utilized in a large number of researches dealing with cognitive impairment, dementia, and Alzheimer’s disease. The cutoff value of MMSE is argued among researchers, and various values are used for the analysis. O’Bryant et al. reported that 4248 participants were analyzed, and a cutoff value of 27 (sensitivity=0.69, specificity=0.91) in a cognitively impaired group (dementia and mild cognitive impairment) was the most valid. So in this study, we adapted 27/26 as a cutoff value of it.
In this study, we compared with GOHAI scores and proportions to each answer in both the groups. Some papers were published on comparison of cognitive function and OHRQOL by GOHAI. Klotz and co-workers surveyed nursing home residents and 70% of the participants had dementia. They did not find any difference in OHRQOL by GOHAI between subjects with dementia and those having no dementia. Ming et al. asserted no significant difference between AD patients and controls by conducting a systematic review and analyzing four studies. Lee et al. concluded that the GOHAI scores are better in normal elderly adults compared with those with cognitive decline by searching 226 community-dwelling elderly people. Lee et al. also reported that the GOHAI scores in normal people are better than those in cognitive impaired people. In contrast to these reports, Zuluaga et al. found that the GOHAI scores in elderly people with cognitive impairment living in a geriatric institution are better than those in normal elderly. Our results show no significant difference between normal and decline cognition. Nevertheless, proportion of answers to some questions was statistically different. The result of this study is found at the crossroad between the results of other previous researches. All of these studies used GOHAI to measure OHRQOL but various results were obtained, caused by the disunification of the progress of cognitive decline, backbone of living, and the society.
After analyzing proportion of answers, we found that the ratio of answer to some questions was difference in both groups. Q2 is about trouble with mastication, and masticatory function was actually lower in the impaired group. On this part, the result of GOHAI matched well with the result of examination by test food. Whereas Q7, 9, 10, 11 that had also different portions of answers are on a category of psychosocial impacts. The frequency that subjects cared what other people think and their esthetics increased in the impaired group. Although type of prosthesis and requirement of prosthodontic treatment affect OHRQOL, our results did not show that subjects in the impaired group assessed their denture on satisfaction and esthetics as same degree with the normal group. Teeth wear causes esthetic problems, and objective assessment by the prosthodontic specialists showed the same result in both the groups. Psychosocial impacts in this study may be affected by their oral health with less remaining teeth rather than problem of prosthesis, and subjects in the impaired group could have negative emotion on their oral health. Depression is common symptom among elderly people who had experience radical change of environment with life events (e.g. retirement, lost member of family or intimate friend). Elderly adults tend to develop depression more than other age groups. Depression could affect whole body health and develop various diseases. Furthermore, cognitive function is related to appearance and level of depression and they interinfluence., By such a physical status, they would have sentiment to deny their oral health.
Mastication changes the secretion of some substances concerning with stress in the central nerve. Chewing reduces stress hormone such as catecholamine in plasma and saliva. Well-mastication links to suppress stress. As chronic stress causes depression, poor masticatory function in the impaired group could cause chronic stress that has potential to develop into depression.
| Conclusion|| |
Elderly people with cognitive decline decrease masticatory function with fewer remaining teeth, and it is revealed that they have trouble of chewing and psychological and oral discomfort caused by oral problems. By taking dental treatment and oral care, problems on OHRQOL must be resolved. Finally, it is essential to encourage the intake of rich nutrition and participate in social activities for the maintenance of cognitive function.
Special thanks to all the staff members of the Division of Occlusion and Removable Prosthodontics, the Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido for their support for the research.
Financial support and sponsorship
The study received Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan
Conflicts of interest
There are no conflicts of interest.
Y. T.: Concepts, design, definition of intellectual content, literature search, data collection, data analysis, statistical analysis, manuscript preparation, manuscript editing, manuscript review, and guarantor. M. S.: Literature search, data collection, data analysis. K. K.: Literature search, data collection, data analysis. S. H.: Concepts, design, definition of intellectual content, data analysis, manuscript review. H. M.: Concepts, design, definition of intellectual content, literature search, data analysis, statistical analysis, manuscript review. H. K.: Concepts, design, definition of intellectual content, literature search, data analysis, statistical analysis, manuscript preparation, manuscript editing, manuscript review, and guarantor.
Ethical policy and Institutional Review board statement
This study was approved by the Ethics Committee of Health Sciences University of Hokkaido (Process Number 2017-123). All the procedures have been performed as per the ethical guidelines laid down by Declaration of Helsinki (1964).
Patient declaration of consent
The authors certify that all the participants provided their written consent to participate in the research and have the analyzed data published.
Data availability statement
Data are available upon reasonable request.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]