longitudinal changes in higher-level functional capacity of an older population living in a japanese...

Longitudinal changes in higher-level functionalcapacity of an older population living in a

Japanese urban community

Yoshinori Fujiwara a,*, Shoji Shinkai a, Shu Kumagai a,Hidenori Amano a, Yuko Yoshida a, Hideyo Yoshida b,Hunkyung Kim b, Takao Suzuki b, Tatsuro Ishizaki c,

Hiroshi Haga d, Shuichiro Watanabe e, Hiroshi Shibata f

a Department of Community Health, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho,

Itabashi-ku, Tokyo 173-0015, Japanb Department of Epidemiology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku,

Tokyo 173-0015, Japanc Department of Healthcare Economics and Quality Management, School of Public Health,

Kyoto University, Kyoto, Japand Faculty of Medical Science and Welfare, Tohoku Bunka Gakuen University, Sendai, Japan

e Department of Gerontology, Graduate School of International Studies, Obirin University, Tokyo, Japanf Department of Psychology, Health and Sports Science, College of Humanities, Obirin University, Tokyo,

Japan

Received 5 August 2002; accepted 30 August 2002

Abstract

This study examined the present state and longitudinal changes in higher-level functional

capacity in a Japanese urban community. Persons aged 65�/84 years living in a suburb of

central Tokyo participated in a baseline survey held in 1991 (n�/814) and followed-up for 8

years. Outcome measures were disabilities in: instrumental self-maintenance (IADL), the

intellectual activity scale (intellectual activity) and the social role scale (social role), as

measured by subscales of the Tokyo Metropolitan Institute of Gerontology Index of

Competence (TMIG-index of competence). At baseline among the three subscales, both older

men and women had the highest prevalence of disability in social role, followed in turn by

intellectual activity and IADL disability. The 8-year longitudinal survey on subjects who had

* Corresponding author. Tel.: �/81-3-3964-3241; fax: �/81-3-3579-4776.

E-mail address: [email protected] (Y. Fujiwara).

Arch. Gerontol. Geriatr. 36 (2003) 141�/153

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no initial disability (229 men and 235 women) in all three subscales of TMIG-index of

competence demonstrated that they were most likely to lose social role function with

advancing age, followed in turn by intellectual activity and IADL. The Cox proportional

hazard model analysis for all 814 participants revealed that baseline level of social role and

intellectual activity significantly predicted the new onset of IADL disability during the 8-year

follow-up period even after controlling for gender, age, and chronic medical conditions. In

summary, disability in social role and intellectual activity do not only likely precede IADL

disability, but also predict significantly the future onset of IADL disability in a Japanese

urban community older population.

# 2002 Elsevier Science Ireland Ltd. All rights reserved.

Keywords: TMIG-index of competence; Instrumental self-maintenance; Intellectual activity; Social role;

Community-dwelling older people

1. Introduction

Functional capacity has been recognized as a crucial component for independent

living in later life. Thus, many previous studies have examined what factors

contribute to decline in functional capacity of older people (Stuck et al., 1999).

However, all of them have focused on decline in basic activities of daily living

(BADL) or instrumental activities of daily living (IADL), but not on higher-level

functional capacity above IADL (Haga et al., 1997; Fujiwara et al., 2000; Ishizaki et

al., 2000). The reasons for it may lie in that an appropriate scale has not been

constructed for measuring higher-level functional capacity of older people.

Lawton (1972) defined and systemized seven stages of competence from the lowest

and most basic function to the highest. The stages were, in ascending order of

complexity, arranged such as life maintenance, functional health, perception and

cognition, physical self-maintenance, instrumental self-maintenance (IADL), effec-

tance, and social role. This model of competence is attractive and has been used as a

theoretical framework in the development of new scales.

Based on Lawton’s model, we developed a multidimensional 13-item index of

competence comprising three subscales (instrumental self-maintenance, intellectual

activity, and social role), the so-called Tokyo Metropolitan Institute of Gerontology

(TMIG)-index of competence (Koyano et al., 1991). This index was designed to

measure three higher-level functional capacities above physical self-maintenance in

community-dwelling older residents that could not be adequately assessed by

existing scales (Koyano et al., 1987, 1991, 1993). Our earlier study demonstrated

good reliability and validity of the index (Koyano et al., 1991).

In 1991, we launched a longitudinal study on aging, the so-called Tokyo

Metropolitan Institute of Gerontology Longitudinal Interdisciplinary Study on

Aging (TMIG-LISA) (Shibata et al., 1997) in which we assessed the higher-level

functional capacity for representative samples of older community residents using

the TMIG-index of competence. Our previous study (Ishizaki et al., 2000) already

identified having poor the intellectual activity score (intellectual activity) and poor

the social role score (social role) as significant predictors of functional decline in

Y. Fujiwara et al. / Arch. Gerontol. Geriatr. 36 (2003) 141�/153142

IADL among older people living in a rural community. However, the study has a few

limitations to be considered. First, we followed the cohort for only 3 years; the

duration may be too short to observe an entire process of higher-level functional

change among initially non-disabled older people. Second, the interrelationship

among three subscales of higher-level functional capacity such as hierarchy and

mutual predictability has not been examined in detail. Moreover, the targeted area

was limited to a rural village; changing patterns in higher-level functional capacity ofolder people may differ depending on residential area and culture (Yukawa and

McCormick, 2000).

TMIG-LISA has continued up to now; the higher-level functional capacity of

older people has been repeatedly measured. Using this data, this study examined the

present state and 8-year longitudinal changes in higher-level functional capacity,

which mainly comprises IADL and socio-psychological factors, especially targeting

on how older people lose each sublevel of the TMIG-index of competence with

advancing age in an urban community older population. This is the first paper todemonstrate Lawton’s hierarchical model in terms of higher-level functional capacity

in older people, and implies that maintaining the higher sublevel of functional

capacity may lead to delaying decline in lower sublevel scores of functional capacity.

2. Methods

2.1. Study area and subjects

The present data were derived from the medical science project of the TMIG-

LISA. Details of this project have been reported elsewhere (Shibata et al., 1997).

The target area for this study was Koganei City, located 25 km west from central

Tokyo. The city, with a population of about 100,000 (population density: 9000

persons/km2), is a typical commuter town of the megacity, Tokyo; 35% of residents

commute to central Tokyo. Older people accounted for 9.7% of total population in

1991, from which we selected 996 older persons aged 65�/84 years as one-tenthrandom sample. Of those selected, 814 persons (81.7%) responded to the baseline

interview survey conducted at home in 1991, after signing informed consent forms,

which had been approved by the ethics committee of the institute. The reasons for no

response to the baseline survey were due to refusals (8.0%), move or inability to

reach (4.2%), institutionalization (3.3%), decease (1.4%), and long-term absence

(1.3%).

2.2. Baseline and follow-up surveys

At baseline survey, well-trained personnel interviewed the subjects at home with a

questionnaire comprising socio-demographic, psychological, physical and medical,

life style and social network items. These data were used to characterize the study

population. The follow-up surveys were conducted every 2 years in the same manner

as the baseline survey.

Y. Fujiwara et al. / Arch. Gerontol. Geriatr. 36 (2003) 141�/153 143

2.3. Assessment of functional capacity

The higher-level functional capacity of older subjects was measured using the

TMIG-index of competence (Koyano et al., 1987, 1991, 1993; Ishizaki et al., 2000).

This is a multidimensional 13-item index (Table 1). With the covariance structure

model, the three first-order factors in the model are interpreted as instrumental self-

maintenance (IADL), intellectual activity, and social role, and the second factor ascompetence. Intellectual activity is thought to correspond to effectance level in

Lawton’s model. The response to each item was ‘yes’ (able to do) or ‘no’ (unable to

do), and scored as 1 for ‘yes’ and 0 for ‘no’. The total score was designed as the sum

of the 13 items, such that a higher score (maximum of 13 points) would indicate a

higher level of competence. Three sublevels of competence were also calculated; a

score of 0�/5 for IADL, a score of 0�/4 for intellectual activity, and a score of 0�/4 for

social role.

According to the TMIG-index of competence and the three subscales, a personwas defined as having a disability, if he/she reported a score of 1 or more below the

respective full mark. That is, a score, below 13 for the total score of TMIG-index,

below 5 for IADL, and below 4 for intellectual activity, and social role, each

indicates the onset of disability.

2.4. Statistical analysis

Using the baseline data, we determined the prevalence rates of disability based on

the total score for TMIG-index of competence and the individual scores for each of

the three subscales (IADL, intellectual activity, and social role) by gender and age

Table 1

The Tokyo Metropolitan Institute of Gerontology Index of Competence

Subscales Questionnaires

Instrumental self-mainte-

nance

(1) Can you use public transportation (bus or train) by yourself? 1 0

(2) Are you able to shop for daily necessities? 1 0

(3) Are you able to prepare meals by yourself? 1 0

(4) Are you able to pay bills? 1 0

(5) Can you handle your own banking? 1 0

Intellectual activity (6) Are you able to fill out forms for your pension? 1 0

(7) Do you read newspapers? 1 0

(8) Do you read books or magazines? 1 0

(9) Are you interested in news stories or programs dealing with

health?

1 0

Social role (10) Do you visit the homes of friends? 1 0

(11) Are you sometimes called on for advice? 1 0

(12) Are you able to visit sick friends? 1 0

(13) Do you sometimes initiate conversations with young people? 1 0

1 indicates ‘yes’ and 0 indicates ‘no’.


group. Data comparisons between age groups and among subscales were tested with

chi-square test or Mann�/Whitney’s U -test.

To examine declining patterns in respective three subscales of TMIG-index of

competence, we followed-up only the subjects who had no disability at baseline in

any of the subscales. Outcome events were defined as a new disability in each

subscale and death of a subject who had shown no disability at the follow-up in the

previous year. We made cumulated proportion curves of disability in each subscalewith each survey year using the actuarial method, on which data the general

Wilcoxon�/Gehan test and Bonferroni’s post hoc multiple comparison were applied.

For evaluating predictive values of social role at baseline for future onset of IADL

or intellectual activity and of intellectual activity at baseline for future onset of

IADL disability during the 8-year follow-up period, we used the Cox proportional

hazards model, controlling for sex, age, and chronic medical conditions (stroke,

hypertension, heart diseases and diabetes). The subjects were all older people (n�/

814) who underwent the baseline survey in 1991.All tests were two-tailed and the level of significance was set at 5%. We analyzed

all data with the SPSS/PC�/ statistical software for Windows version 10.0.

3. Results

Table 2 summarizes subject characteristics at baseline by gender: their mean ages

were about 72 years; over half of them were not engaged in work (51.4% for men and

86.5% for women); their mean education years were 11.7 for men and 9.5 for women;they rated their health fairly well; substantial proportions of them reported to have

chronic medical conditions, but very few had disability in BADL; they reported less

contact with neighbors than with distant family (i.e., family members not living with

the respondent) or distant friends.

Table 3 shows higher-level functional capacity at baseline in this population as

assessed by the TMIG-index of competence. In both younger (65�/74 years) and

older age (75�/84 years) groups, regardless of gender, disability in social role was

most prevalent, followed in turn by disability in intellectual activity and IADL.The older age group had higher prevalence of disability in most of the 13 items and

composite subscales for both men and women. When comparing the magnitude of

difference in each disability rate between the two age groups in men and women,

however, those with a disability in social role and intellectual activity did not always

surpass those with a disability in IADL.

The baseline survey identified older people who had no disability in all three

subscales: IADL, intellectual activity, and social role (229 men and 235 women), who

comprised the cohort for the 8-year follow-up. Figs. 1 and 2 depict how these oldermen and women lost higher-level functional capacity with advancing age. Although

the pattern slightly differed across gender, older people generally were most likely to

lose social role function, followed in turn by intellectual activity (P B/0.001 vs. social

role for both men and women) and IADL (P�/0.241 and P B/0.001 vs. intellectual

activity for men and women, respectively). At eighth year of follow-up, cumulative


proportions of disability in social role recorded 68.6% for men and 62.5% for

women, those in intellectual activity 52.8% for men and 52.5% for women, and those

in IADL disabilities 46.8% for men and 33.7% for women. These outcome events

included 31 deaths of subjects (22 men [9.6%] and 9 women [3.8%]) without disability

in the previous follow-up surveys.

Table 2

Subject characteristics at the time of baseline survey in 1991 (n�/814)

Men Women P -valuea

n�/368 n�/446

Socio-demographic variables

Age (years, mean9/S.D.) 71.69/5.2 72.29/5.2 0.101

Number of family members (mean9/S.D.) 3.29/1.6 3.39/1.9 0.886

Education (years, mean9/S.D.) 11.79/3.7 9.59/2.6 B/0.001

Occupation (% not being engaged in work) 51.8 85.8 B/0.001

Longest-term occupation

Employees (%) 81.5 22.6 B/0.001

Self-employed workers (%) 18.2 7.5 B/0.001

Family workers (%) 0.0 3.6 B/0.001

Keeping house and others (%) 0.3 65.2 B/0.001

Psychological variables

Self-rated health (fair to poor, %) 18.3 24.5 0.039

Geriatric depression scale score (mean9/S.D.) 7.69/5.6 9.49/5.6 B/0.001

Physical and medical variables

Use of outpatient care in the past month (yes, %) 60.6 66.2 0.107

Hospitalization in the past year (yes, %) 7.4 8.4 0.695

History of stroke (present, %) 6.3 2.3 0.004

History of hypertension (present, %) 34.2 37.5 0.339

History of heart diseases (present, %) 21.2 19.7 0.660

History of diabetes (present, %) 12.0 7.3 0.029

Hearing impairment (mildly or severely impaired, %) 8.3 8.1 0.750

Visual impairment (mildly or severely impaired, %) 4.4 8.2 0.057

Walking (partly dependent or impossible, %) 1.9 2.1 0.319

Eating (partly or completely dependent, %) 2.2 0.7 0.046

Incontinence (sometimes or always, %) 2.5 3.2 0.434

Dressing (partly or completely dependent, %) 1.9 0.9 0.397

Bathing (partly or completely dependent, %) 2.8 1.6 0.508

Chewing status (slightly or severely limited, %) 54.3 58.7 0.139

Body mass index (kg/m2, mean9/S.D.) 21.89/2.8 22.59/3.5 0.094

Life style and social network-related variables

Alcohol drinking status (current drinker, %) 58.0 15.8 B/0.001

Smoking status (current smoker, %) 35.2 10.3 B/0.001

Habit to take a walk or light gymnastics (no, %) 45.2 49.8 0.204

Habit to do sports or take an exercise (no, %) 77.5 85.4 0.004

Contact with neighborhoods (seldom or no, %) 65.4 49.4 0.014

Contact with distant friends (seldom or no, %) 34.6 28.7 0.033

a P -values are based on chi-square test or Fisher’s test, except continuous data where P -values are

derived from t -test or Mann�/Whitney’s U -test.


Table 3

Higher-level functional capacity of the subjects at the time of baseline survey in 1991 (n�/814)

Men (age group, years) P -value a Women (age group, years) P -value a

65�/74

(n�/260)

75�/84

(n�/108)

65�/74

(n�/297)

75�/84

(n�/149)

Total scores of Tokyo Metropolitan Institute of Gerontology-index of

competence (mean9/S.D.)

12.29/1.7 11.29/2.8 B/0.001 12.19/1.7 10.59/3.3 B/0.001

Subscales

Instrumental self-maintenance (mean9/S.D.) 4.99/0.7 4.49/1.3 B/0.001 4.99/0.6 4.39/1.4 B/0.001

Intellectual activity (mean9/S.D.) 3.89/0.6 3.69/0.9 0.004 3.79/0.7 3.29/1.1 B/0.001

Social role (mean9/S.D.) 3.69/0.9 3.19/1.3 B/0.001 3.59/0.9 2.99/1.3 0.063

Instrumental self-maintenance (no, %)

Using public transportation (bus or train) by oneself 3.5 10.2 0.020 2.0 22.4 B/0.001

Shopping for daily necessities 2.3 11.3 0.001 1.7 13.5 B/0.001

Preparing meals by oneself 4.2 20.4 B/0.001 2.7 10.9 0.001

Paying bills by oneself 1.2 5.6 0.022 1.0 10.1 B/0.001

Handling one’s own banking 2.7 11.1 0.003 2.7 15.5 B/0.001

Disability in at least one item of the five (present, %) 5.8 24.5 B/0.001 4.7 29.5 B/0.001

Intellectual activity (no, %)

Filling out forms of pension 1.9 9.3 0.003 3.7 17.7 B/0.001

Reading newspaper 1.9 7.4 0.024 5.8 16.9 B/0.001

Reading books or magazines 8.1 13.0 0.173 11.2 27.0 B/0.001

Being interested in stories or programs dealing with health 7.7 13.9 0.079 6.8 13.6 0.022

Disability in at least one item of the four (present, %) 14.7 26.9 0.008 17.3 41.1 B/0.001

Social role (no, %)

Visiting the homes of friends 20.1 33.3 0.010 18.0 35.9 B/0.001

Being called on for advise 8.5 18.7 0011 12.6 32.6 B/0.001

Visiting sick friends 5.4 18.5 B/0.001 5.4 18.5 B/0.001

Initiating conversations with young people 10.0 22.2 0.004 13.6 20.9 0.054

Disability in at least one item of the four 24.3 45.8 B/0.001 28.7 52.8 B/0.001

a P -values were derived from comparisons on nominal data between two age groups with chi-square test or Fisher’s test except continuous variables with

Mann�/Whitney’s U -test.

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Table 4 shows that disability in intellectual activity and social role at baseline

significantly predicted the subsequent onset of IADL disability during an 8-year

follow-up period (hazard ratios (HR)�/1.66, P B/0.001; HR�/1.52, P�/0.001,

respectively). HR for disability in intellectual activity at baseline remained significant

even after controlling for gender, age and chronic medical conditions (HR�/1.39,

P�/0.021). Disability in social role at baseline also predicted significantly the future

onset of disability in intellectual activity (HR�/1.46, P�/0.002), though marginally

significant after adjustment (HR�/1.27, P�/0.063).

Fig. 1. Declining patterns of the three subscales of Tokyo Metropolitan Institute of Gerontology Index of

competence for men in Koganei City. Actuarial method survival curves. Significant differences at P B/0.01

between instrumental self-maintenance and social role, and intellectual activity and social role.

Fig. 2. Declining patterns of the three subscales of Tokyo Metropolitan Institute of Gerontology Index of

competence for women in Koganei City. Actuarial method survival curves. Significant differences at P B/

0.01 between each of three subscales (instrumental self-maintenance, intellectual activity and social role).


Table 4

Hazard ratios for each disability at baseline in higher subscales against the onset of instrumental self-maintenance or intellectual activity disability during the 8-

year follow-up period (n�/814)

Subscales of dis-

ability

Against instrumental self-maintenance Against intellectual activity

Unadjusted hazard

ratioa

Adjusted hazard

ratiob

95% Confidence

interval

P -value Unadjusted hazard

ratioa

Adjusted hazard

ratiob

95% Confidence

interval

P -va-

lue

Intellectual activ-

ity

1.66 1.26�/2.18 B/0.001 �/

Social role 1.52 1.20�/1.93 0.001 1.46 1.15�/1.86 0.002

Intellectual activ-

ity

1.39 1.05�/1.84 0.021 �/

Social role 1.18 0.92�/1.51 0.183 1.27 0.99�/1.63 0.063

a Adjusted for only sex.b Adjusted for age, sex, and chronic conditions (stroke, hypertension, heart disease, diabetes).

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4. Discussion

This study examined the present state and longitudinal changes in higher-level

functional capacity of an older population living in a Japanese urban community as

assessed by the TMIG-index of competence. The baseline cross-sectional analysis

showed that in both older women and men disability in social role was most

prevalent, followed in turn by intellectual activity and IADL. Since the prevalencerate of disability depends on the clearance rate (i.e., the rate for those who responded

‘‘yes’’ to an index), the results do not necessarily imply that older people are most

likely to lose social role function, followed by intellectual activity and IADL. The

comparison of differences in each disability rate between younger (65�/74 years) and

older (75�/84 years) age groups in each gender group indicated that the number of

persons with disability in social role and intellectual activity did not always surpass

those with a loss in IADL functioning.

Alternatively, the longitudinal analyses of the subjects who had shown nodisability in three subscales at baseline clearly showed that older people living in

an urban area were most likely to lose social role function with advancing age,

followed in turn by intellectual activity and IADL. The discrepancy between cross-

sectional and longitudinal data may be explained by cohort effect. For example,

persons in the older age group might have had lower level of IADL than did these in

the younger age group, potentially leading to an exaggeration of age-related IADL

change for cross-sectional analysis. Since the natural course of functional state in

older people would be reflected in longitudinal data, it is plausible to think that thepresent data support the hypothesis that higher-level functional status of older

people likely declines in accordance with the hierarchical order from highest to

lowest.

However, it should be noted that higher-level functional capacities interrelate with

each other, and are affected by socioeconomic status, educational attainment,

cultural background, hobbies or personal choices (Haga et al., 1997; Ishizaki et al.,

2000). We also previously reported that chronic medical conditions (Fujiwara et al.,

2000), self-rated health (Haga et al., 1995), physical strength (Shinkai et al., 2000)and baseline scores of each competence (Haga et al., 1997) contributed to changes in

the TMIG-index of competence in community-dwelling older people. All these

potential factors may well be distributed differently, for example, between older

populations of urban and rural areas. Therefore, further studies are needed to

conclude whether the higher-level functional status of older people is always likely to

decline in accordance with the hierarchical order from highest to lowest.

This study also showed that the baseline level of intellectual activity and social role

significantly predicted the future onset of IADL disability within the 8-year period.This result is consistent with our previous study (Ishizaki et al., 2000), in which

having poor intellectual activities and poor social roles were identified as significant

predictors for functional decline in IADL among older people living in a Japanese

rural community. Taken together, to our knowledge this is the first paper to

demonstrate Lawton’s hierarchical model on higher-level functional capacity in

older people.


Lawton’s model provides the basis of TMIG-index of competence. The intellectual

activity subscale consists of four items: filling out forms for pension, reading

newspapers, reading books or magazines, and interest in news stories or programs

dealing with health. These can be categorized as cognitive stimulating activities.

Wilson et al. (2002) reported that frequent participation in cognitive stimulating

activities was associated with reduced risk of Alzheimer disease. At the same time,

intellectual activity subscale is considered to enable to detect a low grade of cognitive

function. Fujiwara et al. (2002) noted that a community-dwelling older person with

mild cognitive decline assessed by MMSE had a lower level of intellectual activity

than did a cognitively intact older person. Greiner et al. (1996) reported that low

normal cognitive function predicted a loss of functional independence in an older

population. Taken together, we can suppose that poor intellectual activity has an

increased risk for future cognitive impairment and concomitant IADL disability.The social role subscale includes four items, which are related to social relations.

Good social relations are one of the key factors for successful aging (Rowe and

Kahn, 1997), and they contribute to improved health of older people because they

are relatively disadvantaged in maintaining and strengthening their integration

(Young and Glasgow, 1998). Many previous studies have reported that higher levels

of social activity and social contact are associated with reduced mortality (Berkman

and Syme, 1979; Blazer, 1982; House et al., 1982; Welin et al., 1985; Schoenbach et

al., 1986; Kaplan et al., 1988; Vogt et al., 1992; Sugisawa et al., 1994), and

maintenance of functional status (Mor et al., 1989; Markides and Lee, 1990;

Strawbridge et al., 1993) among older people. Our previous 10-year prospective

study also showed that higher levels of social activity are associated with a lower

incidence of basic ADL disability (Haga et al., 1997). The present finding that

disability in social roles significantly predicts the future onset of IADL disability is

generally consistent with such previous studies.Regarding the associations between social roles or intellectual activity, and IADL,

the present results have two implications. First, an assessment of intellectual activity

and social role with the TMIG-index of competence may enable earlier detection of

older persons who are at an increased risk for future onset of IADL disability and

may lead to a possible intervention. In this context, it should be noted that in 2000,

Japan’s Ministry of Health, Labour and Welfare introduced the TMIG-index of

competence as a tool for assessing higher-level functional capacity of older persons

in various situations under the Health Care Law for the Aged (Haga, 2000). Second,

maintaining good intellectual activity and social role may prevent the future onset of

IADL disability in community-dwelling older people. Most of the items in

intellectual activity and social role do not ask the older person about his/her

capability, ‘‘can do?’’ but about habitual behavior, ‘‘do do?’’. As shown in an adage

‘‘use it or lose it’’ (Bootsma-van der Wiel et al., 2001), several studies have

documented that inactivity eventually leads to decline in physical and cognitive

functioning among older people (Powell, 1974; Allen et al., 1999; Wilson et al.,

2002). Intellectual activity and social role are potentially modifiable functions by

promoting a healthy change in the life style of our older population. Future study is


needed to develop effective intervention programs and to determine risk factors for

functional decline in intellectual activity and social role.

Acknowledgements

This study was conducted as part of the Tokyo Metropolitan Institute of

Gerontology Longitudinal Interdisciplinary Study on Ageing (TMIG-LISA). Theauthors express sincere thanks to the research members of the TMIG-LISA.

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