The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

ARTICLES

The effect of ADL quality on sense of deliciousness
and sense of taste in nursing homes in Sri Lanka
Toru Takiguchi1,4)，Yoshiaki Yamada2)，Geethani Kandaudahewa3)，
Chie Yamamura2)，Kakuhiro Fukai4)，Atsushi Takayanagi4)1）(Former) JICA Advisor's Office, the Ministry of Healthcare & Nutrition, Sri Lanka
Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and
Dental Sciences
3）
Oral Health Unit, the Ministry of Healthcare & Nutrition, Sri Lanka
4）
Fukai Institute of Health Science
2）

Key Words ：Sense of deliciousness, Sense of taste, Activities Daily Living (ADL), General Condition,
Multiple Logistic Regression Analysis

a necessity to decrease the burdens caused byIntroduction

CDS-AA.

The Change of disease structure accompanying
aging (CDS-AA) in Japan has resulted in the adop-

The campaign to prolong healthy life expectan-tion of health, medical and welfare measures suchcy proposed by WHO1) in 2000 is the ultimate pur-as the Health Promotion Law (2002) along withpose of measures to deal with CDS-AA in both

Healthy Japan 21 Campaign: A New Health Policy

developed countries and developing countries. In

stfor Japan in the 21 Century, as well as the Long-

order to achieve the goals of this campaign, toTerm Care Insurance System (2000). Further-maintain masticatory & swallowing functions andmore, Health and Medical Service Law for thesense of taste (sense-T) are indispensable elements

Elderly will be drastically reformed in the nearfor the elderly. The function of sense-T as a sensor

future. However, according to the WHO'sis linked to sense of deliciousness (sense-D), and it

Web01), the CDS-AA is becoming an

not only contributes to QOL but also various cru-

urgent problems not only in advanced countries

cial functions in the elderly. Namely, the function

but also in developing countries other than sub-of sense-T contributes to the recovery of Activi-

Saharan African countries which suffer socioeco-

ties of Daily Living (ADL), to ensuring food bynomic and medical difficulties due to epidemics ofmeans of distinguishing decayed food or foreign

serious infectious diseases such as HIV/AIDS andobjects, and to allow perception and avoidance ofmalaria. From an international standpoint, there isexcessively salty foods which are likely to con-recent report

tribute hypertension2) and stroke3). In other words,
sense-T has a very important physiological func【著者連絡先】〒341-0003 埼玉県三郷市彦成3-86
深井保健科学研究所
主席研究員 瀧口 徹
TEL&FAX： 048-957-3315
E-mail ： taki8020@mth.biglobe.ne.jp

tion as the gatekeeper4) of food consumption.
However, there have been few comprehensive
studies which have evaluated links between general conditions such as ADL and dental conditions
such as present teeth, wearing of denture, and―4―

ヘルスサイエンス・ヘルスケア

Volume 7，No.1（2007）

sense-T even though decline in sense-T is serious

ment organization (NGO) located in Colombo ( pop-

problem for the elderly. One of the reasons for theulation 2.4 million), Kalutara district (1.1 million) inlack of such studies is the difficulty of synergetic

Western Province and Galle district (1.0 million) inand synthetic research, because this issue is linked

Southern Province. These facilities are funded by ato the fields of medicine, dentistry and nutrition. In

combination of governmental subsidy, private

addition, there may be relatively large differences

donations and pensions. The population of theseof sense-D and sense-T caused by diversities inthree districts accounts for about 25 % of country's

daily habits such as smoking, alcohol drinking,total population, and capital cities of these districts

daily food habits, and general health conditions

are the most urbanized areasWeb03) in Sri Lanka.

among different countries, regions, or religious

Generally, unlike at their individual homes, simi-groups. To elucidate this question quantitatively is

lar meals are served to all residents of a nursing

a challenge that must be undertaken in order tohome. Therefore, there is less variation in thedevelop measures to combat global aging prob-

types of foods, method of preparation, and fresh-lems and offer technical assistance in the areas ofness of food than there would be at individual

health, medicine, and welfare to other countries.

homes. This was a major reason why these facili-

The aim of this study is to analyze the relationships between

ties were selected for this study. This restriction

ADL and sense-D and sense-T ofof participants is an epidemiological method tothe elderly at nursing homes in Sri Lanka5) while

control confounding factors. However, because

adjusing for background factors such as generalmeals are likely to be at the 6 facilities, indepen-and dental conditions.

dent categories for each facility were entered as avariable in the Multiple Logistic Regression Analysis (MLRA) discussed below, in order to look for

Methods

differences in tendencies at the facilities. This sur-1）Background
Sri Lanka is a developing, multiracial country,

vey was conducted anonymously after obtaining

located in the Indian Ocean near the equator, withthe permission of the administrators and the resi-

a population of approximately 20 million. It has adents in the nursing homes. Formal ethicalsocial democratic parliamentary system of govern-

approval was not required because this survey

ment under which over 80% of hospitals belong toconsisted of only questionnaire and non-invasive

government and medical services are free ofobservations such as count of number of teeth or

Web02)

charge. Literacy ratemeasurements such as weight and height.

of Sri Lanka (90.4%,

ranking 78th in the world) is on par with Republicof China (90.9%) and Mexico (90.3%) and far higher

3）Dependent variables and independent variables

than the neighbouring countries in South Asia

including target variables

such as India (61.0%, ranked 145th), Pakistan(54.2%,

Dependent variables Xa and Xb in Table 1 arerdthtarget indices which are objective variables in theranked 153 ), and Bangladesh (41.1%, ranked 165 ).

MLRA. Xa is the subjective sense-D (whether the
food tastes delicious or not). Xb is subjective sense-

2）Participants
The participants of this study are 188 elderly

T (whether the taste declines or charges). These

people 65+ years old (91 males, 97 females) living

indices were consolidated into two categories

in six nursing homes administrated by non-govern-because with three categories, the peripheral fre―5―

The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

cut-off point for selecting variables in backward-

quencies of category 2 were only 1 to 6.
LTCN3 and LTCN2 in Table 1 are target indices

MRLA using -2LL. The backward procedure waswhich quantify ADL. LTCN6 is abbreviation of

repeated until the difference of before and afterLong-Term Care Need , which is provisional of six

nest-mode χ 2 test value reached the probability of

Web04)

levels of criteria

the cut-off point. Consequently, a final model withdrawn up in 1997 by the Min-

maximum goodness-of-fit was confirmed.

istry of Health, and Welfare in Japan. The original

The contract of all categorical items except

six levels of LTCN6 were consolidated into three
categories as LTCN3 (categorized as 0：0，1：1-2，

nursing homes was

simpleand the first cate-

2： 2-5) and two categories as LTCN2 (categorized

gories were used as reference categories. The con-

as 0： 0， 1： 1-5) respectively. Table 2 shows thetract of nursing homes item isclassification system as translated from Japaneseother unrelated categories were used as reference

into English by the authors. These criteria werecategories.

indicator , and all

In addition, a Kendall's τ correlation coefficientused in nursing homes in Sri Lanka after being

matrix was obtained in order to easily interprettranslated into the Sinhalese and Tamil language.

the links between target LTCN2 (or LTCN3) andconfounding factors.

4）Analyses（1）Basic Statistics of important indices

Results

The distributions of frequency of age and gen-1）Basic Statistics of important indicesder, as well as and the correlation coefficients

The Kendall's τ correlation coefficient between

between gender and number of present teeth, andbetween sense-D and sense-T were calculated.

sense-D and sense-T was 0.31 (p<0.01), which is（2）Trend analyses on simple factors by Cochran-equivalent to a 9.6% contribution rate. Figure 1

Armitage Trend Test (CAT-test).6）

shows the distribution of participants' ages. Frequencies of age groups by five years shows uni-Linear trends between LTCN2 and sense-D andsense-T were analyzed by CAT-test.

modal distribution, and the mean (SD) ages of（3）Trend analyses on multiple factors (MLRA)

males and females were 75.0 years (6.4) and 76.6

The indices used in the analyses shown in Table

years (6.6) respectively. Although the mean age of

1 are composed of six classifications and 21 indices.

females was slightly higher, the difference is statis-

The classifications are: i) gender, ii) age, iii) present

tically insignificant according to the Student's t-teeth & prosthesis, iv) basic diseases, v) physicalconditions, and vi) daily life habits. Tumor, stroke
and liver diseases were eliminated from basic diseases because the positive rates were under 5 %.
All variables except

age

and

total amount ofdiseases are categorical variables.
Backward-MLRA7, Web05), a type of MLRAs using-2 Log Likelihood (-2LL) as a criteria for eliminating insignificant variables one after another up to
the optimum goodness-of-fit model were perFig.1

formed. A probability of 0.20 was adopted as the―6―

Age Distribution

ヘルスサイエンス・ヘルスケア

Volume 7，No.1（2007）

test. The overall mean age of participants was 75.8

fewer than 10 PT, and only 6.4% had more than 20

years, 56% werelate elderly , defined as 75+

PT. The mean number (SD) of PT was 4.77 (6.76)

years old in Japan. The oldest participants of bothfor males and 5.66 (7.53) for females, and there wasgenders were 96 years old.

no statistically significant difference between gen-

Figure 2 shows the distribution of the level ofders. The Pearson's correlation coefficient between

LTCN6 using the criteria shown in Table 2. Theage and LTCN6 is small (r=0.1673) but significant

distribution shown in Figure 2 is also unimodal,(p<0.05).

Level 1 andTable 3 shows the distribution of sense-D andLevel 2 are approximately 26% each, for a total of

Sense-T of elderly in nursing homes by LTCN6

around 50 %.

and gender.

like the age distribution (Figure 1).

Level 0 and 5 are 22.3%, 2.7%

respectively.
2）The trend analyses on simple factors

Figure 3 shows the distribution of number ofpresent teeth (PT) in the participants. 40.4% of par-Table 4 shows the trends between LTCN2 andticipants had 0 PT, making this the mode of thesense-D, Sense-T by CAT-Test6). XT: linear trends

PT distribution. Frequencies of participants withof both sense-D and Sense-T are significant

PT greater than 0 decreases steadily from 1 PT

(p<0.05) and XQ: Quadratic trends of both senses

all the way up to 32 PT. 78.2% of participants had

are insignificant. Therefore, a linear uptrend wasconfirmed between LTCN2 and sense-D, sense-T
as far as the simple factor analyses are concerned,
without considering confounding factors mentioned below.
3）The trend analyses on multiple factors
Table 5 shows the results of MLRA using
sense-D as the objective variable and the 21 independent variables shown in Table 1 including thetarget index LTCN3. The final goodness-of-fit

Fig.2 Distribution of Level of Long-Term Care Need（LTCN）− ADL measured by Level of LTCN −model was arrived at through 17 steps of variablereduction using -2LL. The reliabilities of the
MLRA model with statistical indices are Nagelkerke R2=0.1657, Omunibus test=0.0157, Hosmer &Lemeshow test p=0.5940, and the results fulfill thestatistical reliabilities7) of the model. The following
five variables were selected by MLRA : LTCN,
gender, heart disease, hypertension and temporomandibular joints (TMJ) pain. Three of theses variables were significant at p<0.05: the second category of LTCN3, gender, and hypertension.
Regarding the relationship between LTCN3

Fig.3

Distribution of the Number of Present Teethand sense-D (Table 5), the second category of―7―

The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

Table.1

Dependent and Independent Variables for Multiple Logistic Regression Analysis (MLRA)LTCN3 was much more significant (p=0.0048 by
MLRA) than the first category. The odds ratioof LTCN3 for category 0 versus category 1 is
5.0 (95%CL: 1.6- 15.3) and for category 0 versus
2 is 3.4 (95%CL: 0.9-12.4). The odds ratio of
hypertension for negative versus positive is 3.6(1.6-8.4). Males showed lower sense-D thanfemales. Hypertension and sense-D by levels of
LTCN3 is illustrated in Figure 4. This figure
reveals a tendency for hypertension to contribute to a decline of sense-D at each level of

Fig.4 The Effect of Level of LTCN and Hypertension on Sense of Deliciousness

LTCN3. The Kendall's τ correlation coefficient・LTCN3:Levels of LTCN consolidated from 6 categories into
3 categories as 0:0,1:1-2, and 2:3-5
・The classification of LTCN was developed by Japan's Ministry of Health, Labour and Welfare(MHLW) and provisionally used to improve the certification system for elderly
people with LTCN.
・Both LTCN3 and hypertension were confirmed as statistically significant factors affecting sense of taste by backward-MLRA.

between hypertension and LTCN3 is -0.1948(p<0.01).
Table 6 shows the results of MLRA using
sense-T as the objective variable and the 21 independent variables in Table 1 including the target―8―ヘルスサイエンス・ヘルスケア

Table.2

Volume 7，No.1（2007）

Criteria for Certification of Long-Term Care Need (LTCN)for the Elderly by MHLW, Japan (1998)

Table.3

Distribution of sense of deliciousness and sense of taste by LTCN and Gender―9―The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

Table.4

Trend Analyses on Sense of Deliciousness and Sense of Taste with level of LTCN1)

Table.5

The relationship between physical condition & lifestyle and sense of deliciousness

index LTCN3. The final goodness-of-fit model waswere selected by MLRA : LTCN3, heart disease,arrived at through 17 steps of variable reduction

hypertension, alcohol drinking, and bowel move-using -2LL. The reliabilities of the MLRA model

ment (BM). Two of these variables are significant :2with statistical indices are Nagelkerke R =0.1883,

the second category of LTCN3 (p=0.0042) andOmunibus test=0.0001, Hosmer & Lemeshow test

third category of BM (constipation, p=0.0343).

p=0.3442, and the results fulfill the statistical relia-

Regarding the relationship between LTCN3 andbilities of the model. The following five variables

sense-T (Table 6), the second category of LTCN3― 10 ―

ヘルスサイエンス・ヘルスケア

Volume 7，No.1（2007）

was much more significant than the first category.

remained up to 14th step in the case of sense-D,

The odds ratio of LTCN3 for category 0 versus

but up to 6th step in the case of sense-T. Defective

category 1 is 4.0 (1.5- 10.3) and for category 0 ver-hearing remained up to 8th step in the case ofsus 2 is 1.4 (0.5- 4.5). The Kendall's ̲ correlation

sense-D but 16th step in the case of sense-T.

coefficient between hypertension and LTCN3 is

As shown in these results, a relationship0.1472 (p<0.05). Odds ratio of constipation for nega-

between LTCN and sense-D and sense-T was con-tive versus positive is 2.1 (1.1- 4.3). Constipation

firmed by MLRA with adjustment for confounding

and sense-T by levels of LTCN3 is illustrated infactors such as general conditions, dental condi-

Figure 5. This figure reveals a tendency for consti-

tions, and health related habits. To facilitate inter-pation to contribute to a decline of sense-T at eachpretation of these factors, a Kendall's τ matrix

level of LTCN3.

and an illustration are shown in Table 7 and Fig-

In the MLRA variable selection process, whenure 6, respectively. The significant simple correla-assessing the effect of different nursing homes ontions which are important for interpreting thesesense-D and sense-T, sense-T was remained up to

MLRAs are as follows: sense-D vs. sense T=0.31

8th step, but sense-D was remained up to 16th step.

(p<0.01), LTCN2 vs. sense-T=0.18 (p<0.01), age vs.

Of the four dental related indices (PT, denture,

LTCN3 or LTCN2=0.13, 0.16 (p<0.05, 0.01), hyper-

Tooth brushing habit, and TMJ-pain), only TMJ-

tension vs. sense-D=0.20 (p<0.01), and BM vs.

pain remained in the final model. PT (3 categories)

LTCN3=0.18 (p<0.05).

Table.6

The relationship between physical condition & lifestyle and sense of taste― 11 ―

The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

Discussion
1） Special characteristics of the sample and variables
It is not clear whether participants and private
nursing homes in this study are representative
samples or not. The average household incomes oftarget areasWeb03) of this study are 1st, 3rd and 4thout of 25 districts in the country. Therefore, theparticipants and facilities of this sample belong torelatively wealthy social circumstances comparedFig.5 The Effect of Level of LTCN and Constipation
on Sense of Taste
・LTCN3:Levels of LTCN consolidated from 6 categories into
3 categories as 0:0, 1:1-2, and 2:3-5
・Item BM(bowel movement) is composed of three categories: 0:normal, 1:often diarrhea, and 2:often constipation.
・Category 1(often diarrhea) was omitted in Figure 5 due tothe small number of subjects.
・Both LTCN3 and BM(constipation) were confirmed as statistically significant factors affecting sense of taste by backward-MLRA.

to the general population.
Regarding distributions of frequency of basic
variables, both genders and early elderly and lateelderly groups are unbiased. Therefore, this sample seems to be appropriate to evaluate most of
the variables. However, distribution of PT isbiased because 80% of the participants have fewer
than 10 PT, which is not adequate for evaluating

Fig.6 Correlation between dependent or independent factors on the sense of taste and sense of deliciousness of themeal― 12 ―

ヘルスサイエンス・ヘルスケア

Table.7

Volume 7，No.1（2007）

Correlation Coefficients (Kendall's τ) between dependent variables and factors (indepedent variables)from Japanese9), andthe number of PT on sense-D and sense-T.
New research in these areas using participantsflavorhas often been dis-

puted because of its ambiguous definition. Actual-that are unbiased r regarding PT will be neces-

ly,

8)

umami

is translated into many English

sary because Kanda's study for example, shows

words as deliciousness, heartiness, savoriness, orthat the threshold becomes higher as missing

fullness of the mouthWeb06).

teeth increase in the case of female.

e） Differences in the five taste elements, as wellas thermal characteristics influence the sensory
and motor aspects of swallowingWeb07).

2）The link between sense-T and sense-D
The differences and similarities between sense-

As described above, sense-D and sense-T are

T and sense-D are as follows:neither perfectly independent nor dependent. Thea）Generally, sense-T is the physiological function

fact thatto perceiving the five taste elements (sweetness,

step, just one step before the final step of thesaltiness, sourness, bitterness and umami) with

MLRA for sense-D, indicates that differences inthe taste buds located at the sides of the tongue

sense-D among facilities were greater than those

Web06)and the other oral mucosa.

nursing homes

remained up to 16thof sense-T. The differences of sense-D seem to be.

b）However, sense-T has been sometimes expressed
9)

caused by not only by the taste elements of sense-using more words (e.g. pungent, harsh, insipid,

T, but also by the types of foods used, method of

metallic).

preparation, and storage methods. Therefore thec） On the other hand, sense-D is comprehensive

definition of sense-D is ambiguous and more diffi-

evaluation of deliciousness that takes into accountcult to measure than sense-T. However, sense-D

various factors such as how food is prepared,

such asfreshness, presentation of food, texture whenlowing function seems to be a very importantchewed, flavor, physiological or psychological con-index to evaluate and improve the daily eating

dition9).

(nursing care food10)) of nursing home residents.

d） The difference between

umami , derived― 13 ―

flavoras well as masticatory & swal-

The effect of ADL quality on sense of deliciousness and sense of taste in nursing homes in Sri Lanka

relation between LTCN and sense-D.

3）Significant Background factors

The relationship between salt intake and hyper-

According to a review on the elderly's sense-T
11)

by Narazaki et al. , aging contributes to an

tension is an established theory, but according toincreasing threshold of sense-T, however previous

Yakura2), the level of sensitivity to salty taste instudies are not in agreement as to the causes of

elderly people with hypertension is still uncertain

this threshold increase. One strong reason for thisbecause the results of studies have been highly

confusion seems to be diversity of physiological,

variable. However, in this study a hypothesis

pathological, psychological and environmental con-which could explain rationally the phenomenon

ditions of the elderly. However, this study focusesthat hypertension causes a decline in sense-D

on elucidating only the relationship between ADL

could not be obtained, because sensitivity to salty

and sense-D, and sense-T. From this point of view,

was not separately evaluated.

adjustment of confounding factors using MLRA

Sakagami12) classified the causes of taste disor-

might be the only one way to avoid confusion inders into four groups: (1) communicative disorders

the evaluation of the causes.

of taste substances, (2) disorders of taste bud cells,

Concerning the process of the backward-MLRA,(3) disorders of taste nerve, and (4) central nerve

dental-related indices other than TMJ-pain shouldsystem disorders. These disorders are related tobe re-examined using samples that are unbiased inaging, drugs, saliva secretion disorders, zinc defi-

terms of number of PT. Otological diseases suchciency, damage to middle ear, etc. According to

as damage to the middle ear are likely to con-the Aiba's report14), taste disorders are classified

tribute to disorder of sense-T because the anterior

into ten groups: zinc deficiency, Idiopathic, drug-

two-thirds of the tongue is controlled by chorda

induced, general diseases, oral diseases, disorders

Web08)

tympani nerve, branch of the facial nerve. In

of taste nerves, simultaneous disorders of smell

remainedand taste, flavor disorders, psychogenic, and oth-

up to 2nd step in sense-D, but 16 step just one

ers. According to the web-site of the University of

before the final model. in sense-T. This result indi-

Wisconsin HospitalsWeb10), the causes are follows:cates that defective hearing is likely to contributeaging ( due to the number of taste buds decrease

to a decline in sense-T as is the noted in previous-with age), Bell's palsy, oral or nasal infection, heavy

ly published classification tables11, 12) of leadingsmoking,

causes of deficiency of sense-T.

syndrome), side effects of medicines, vitamin B12

this study, variable

defective hearingthRegarding hypertension, a report by the U.S.

mouthdryness(including

・・

Sjogrenor zinc deficiency and others.

National Institutes of Health on the prevention,

Of these causes, zinc deficiency is one of thedetection, evaluation, and treatment of Hyperten-

most important common clinical causes. Lack of

13, Web09)

recommends a habitual daily brisk

zinc prolongs the turnover time of taste bud cells,

walk for preventing hypertension. Since elderly

sion

and this causes a decline in sense-T. However,people with low levels of ADL are likely get lessthere seem to be no previous studies which refer

exercise, high blood pressure is inevitable unlessto links between BW (constipation) and sense-T.

effective daily rehabilitation programs are intro-

According to Aiba14), there are over a hundred

duced. However, there is a mild negative correla-drugs which cause taste disorders, and about 40%

tion between LTCN3 and hypertension, andof cases involve low zinc levels in the blood. In

hypertension acts as a confounding factor in theparticular, diuretics, antihypertensives, antibiotics,― 14 ―

ヘルスサイエンス・ヘルスケア

Volume 7，No.1（2007）

drugs for diabetes, and other drugs which act as

There seem to be no previous systematic studies

zinc chelating agents are likely to lower zinc levels

which deal with ADL as an apparent direct cause

in the blood. Basic diseases such as diabetes,of the decline of sense-D or Sense-T. At least, ADL

hypothyroidism,

is not referred as a genuine cause in the classifica-orcerebral-vasculardiseases15)

cause chronic constipation , and long-term bedtion tables or reviews11,12,13, Web10).

rest and lack of exercise cause lack of bowel
movement, which also contributes to chronic con-Conclusion

15,16)

stipation. This seems to be the key to explain-

According to the results of this study, the links

ing these phenomena. Hence, there is possibility

between the decline of ADL of the elderly and thethat special dosages of drugs to treat elderly peo-

decline of sense-D and sense-T were statisticallyple with constipation or the basic diseases men-significant after adjusting for confounding factors

tioned above contribute to taste disorders because

using MLRA. In addition, a unique relationshipof the zinc-chelating characteristic of the drugs.

between blood pressure and BM (constipation) andOn the other hand, the case-control study by S.M.

sense-D and sense-T was indicated. It should be

Green, et al.17) shows that the pressure ulcers ofconfirmed whether these significant relationships

long-term bedridden elderly have been accompa-

also hold true in Japan and other countries. Prob-

nied significantly by both malnutrition and tastelems to consider when new studies are planned

disorders, and are likely to be healed by courte-

include: objective tests (e.g. sense of taste, saliva

ous nursing. This result implies that looking atsecretion), drugs history, and large number of par-related aspects such as nutrition and quality of

ticipants. In addition, since this issue involves thenursing may be essential for the prevention of dis-fields of medicine, dentistry and nutrition, it will beorders of sense-D and sense-T.

essential for experts in these three fields to coop-On the other hand, some researchers and clini-

erate with each other on this type of research. In

cal doctors consider dry mouth to be the most sig-

the light of goals of sustaining QOL, preventive

nificant factor of taste disorders. According tonursing cares for the elderly and preventive man-these opinionsweb11,12),

the most common cause ofagement of general conditions such as hyperten-

taste problems, especially in the elderly, is prob-

sion, strokes, and pressure ulcers, further studies

lems in the mouth - with teeth or saliva. Any con-on the links between deterioration of ADL anddition which results in a dry mouth can cause

decline of sense-D and sense-T will be beneficial

problems because saliva is essential for taste.

for rapidly aging societies.

Chemicals in food or drink dissolve in saliva andAcknowledgements

this bathes the taste buds. In a dry mouth, theThe authors are indebted to the representatives

chemicals never reach the taste buds .

and staff members of six nursing homes in Sri4）Links between ADL and sense-D and sense-T,

Lanka for their helpful cooperation.

adjusting for confounding factors
References（Websites）

As seen in the results of the trend analyses(Table 4) by both CAT-test and MLRAs, it was
confirmed that both sense-D and sense-T significantly increase linearly with the decline of ADL.

Web01） WHO: The world health report: Chapter 1:
Global Health: today's challenges ［Web page］Available at― 15 ―

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スリランカの要介護施設入所高齢者の全身状態、歯科状態を調整した
日常生活動作能力と美味感覚と味覚との関係分析

瀧口

徹 1，4），山田 好秋 2），Geethani Kandaudahewa3）
山村 千絵 2），深井 穫博 4），高柳 篤史 4）

1）

前 JICA スリランカ保健省アドバイザー室

2）

新潟大学大学院歯学総合研究科 摂食環境制御学講座 口腔生理学分野

3）

スリランカ保健省歯科保健担当室4）

深井保健科学研究所

キーワード：食事の美味感覚、味覚、日常生活動作能力、全身状態、多重ロジスティック回帰分析

目的：味覚は食事の美味感覚に繋がって高齢者の QOL の維持のみならず塩分、糖分等過剰摂取を防ぐ等、
健康寿命の延伸にも関係する必須の機能である。そこで本研究の目的は日常生活動作能力（ADL）と美味
感覚および味覚の関連を交絡因子である全身状態等の背景要因を調整して解析することである。
対象および方法：スリランカ国の 6 つの民間高齢者介護施設の 65 歳以上の高齢者 188 名を対象に問診した。
目的変数は美味感覚（食事の美味しさ）と味覚の２指標説明変数として ADL、全身的状態、歯科的状態および生活習慣等21 指標を独立変数として変数減少法の多重ロジスティック回帰分析（MLRA）を行った。
結果および考察：高齢者の ADL 低下と美味感覚および味覚との関連が MLRA で交絡因子を調整しても有意であった。歯科関連指標に関しては顎関節痛と美味感覚の関連が示唆された。背景因子である血圧と美味感覚、便通（便秘）と味覚とに関して報告例の無い特異な関係が有意であった。ADL と美味感覚とのオッ
ズ比は 5.0（95%CL: 1.6-15.3）、高血圧の有無と美味感覚は 3.6（1.6-3.4）、ADLと味覚は 4.0（1.5-10.3）、便秘の有無と味覚は 2.1(1.1-4.3)であった。今後の調査において味覚異常を引き起こす可能性が高い幾つかの重要な要因、すなわち入所者の運動、便秘、薬剤服用歴（亜鉛キレート剤等）、また口腔乾燥を引き起こす唾液の分泌低下の有無等を押さえる必要がある。この種の研究が高齢者の QOL の維持と介護予防の観点から、要介護状態の悪化と美味感覚と味覚の減退の関連について各国における今後の研究が超高齢社会対応策に繋がると考察された。
Health Science and Health Care 7（1）：4−17，2007― 17 ―