Aichi Gerontological Evaluation Study Research Articles

Social participation and the combination of future needs for long-term care and mortality among older Japanese people: a prospective cohort study from the Aichi Gerontological Evaluation Study (AGES)

ObjectivesOur study aimed to examine the longitudinal association between social participation and both mortality and the need for long-term care (LTC) simultaneously.DesignA prospective cohort study with 9.4 years of follow-up.SettingSix...

Exploring 2.5-Year Trajectories of Functional Decline in Older Adults by Applying a Growth Mixture Model and Frequency of Outings as a Predictor: A 2010-2013 JAGES Longitudinal Study.

BackgroundWe explored the distinct trajectories of functional decline among older adults in Japan, and evaluated whether the frequency of outings, an important indicator of social activity, predicts the identified trajectories.MethodsWe analyzed data on 2,364 adults aged 65 years or older from the Japan Aichi Gerontological Evaluation Study. Participants were initially independent and later developed functional disability during a 31-month follow-up period. We used the level of long-term care needs certified in the public health insurance system as a proxy of functional ability and linked the fully tracked data of changes in the care levels to the baseline data. A low frequency of outings was defined as leaving one’s home less than once per week at baseline. We applied a growth mixture model to identify trajectories in functional decline by sex and then examined the association between the frequency of outings and the identified trajectories using multinomial logistic regression analysis.ResultsThree distinct trajectories were identified: “slowly declining” (64.3% of men and 79.7% of women), “persistently disabled” (4.5% and 3.7%, respectively), and “rapidly declining” (31.3% and 16.6%, respectively). Men with fewer outings had 2.14 times greater odds (95% confidence interval, 1.03–4.41) of being persistently disabled. The association between outing frequency and functional decline trajectory was less clear statistically among women.ConclusionsWhile the majority of older adults showed a slow functional decline, some showed persistent moderate disability. Providing more opportunities to go out or assistance in that regard may be important for preventing persistent disability, and such needs might be greater among men.

The Association between Social Support and Incident Dementia: A 10-Year Follow-Up Study in Japan.

Social support is important for the health of elderly populations. However, its longitudinal effect on incident dementia is unclear. We used the Aichi Gerontological Evaluation Study (AGES) project data to investigate the longitudinal effect of social support on dementia onset. Functionally independent older people at baseline (n = 14,088) in 10 municipalities were followed from 2003 to 2013 using National Long-term Care Insurance System data. Social support was assessed by the following support sources: co-residing family, family or relatives living apart, and friends or neighbors. Cumulative incidence of dementia was 14.6% and 18.7% for men and women, respectively. Cox proportional hazard models were employed by gender to investigate the association between social support and dementia onset adjusting for age, health status, health behaviors, subjective cognitive complaints, depression, and other socioeconomic factors. Gender differences were observed in the association between social support and incident dementia. Support from co-residing family members was protective among men, whereas among women, no effect of social support on dementia was observed. Among other social factors, community engagement was protective for women, while for men, being married was associated with lower incidence of dementia. The association between social support and dementia seems to differ by gender. When we design programs to promote social interactions among the elderly, we need to take into account such gender differences.

Social factors relating to depression among older people in Japan: analysis of longitudinal panel data from the AGES project

Objectives: Preventing the onset of depression among older people in Japan requires clarifying the social determinants of depression by using longitudinal data, while also taking biological and psychological factors into account. Identification of such determinants may enable more active intervention through social policy. We aimed to reveal the social factors related to depression in Japan’s older people and consider associated policy implications.Method: Panel data obtained from a longitudinal survey (Wave 1 to Wave 2) of 3464 elderly subjects, aged 65 years or more, as part of the Aichi Gerontological Evaluation Study (AGES) project was employed. The outcome variable was depression, as evaluated by the Geriatric Depression Scale. Frequency of meeting with friends, social support, hobbies, participation in organizations, life events, illness, self-rated health, instrumental activities of daily living, and sense of coherence were entered as explanatory variables within a logit model for each gender.Results: Of the subjects without mental illness or depression at Wave 1, 14% had become depressed by Wave 2. In both men and women, life events predicted increased odds of depression, while sense of coherence predicted reduced odds. The frequency of meeting with friends, hobbies, and self-rated health predicted reduced odds of depression in men, while age predicted increased odds in women.Conclusion: Overall, social interaction is important for preventing depression in Japan, and that the establishment of a system capable of promoting social interaction and providing care to the elderly during life events may be a useful social policy approach to preventing depression.

Cohort study on living arrangements of older men and women and risk for basic activities of daily living disability: findings from the AGES project

BackgroundLiving arrangements of older adults have changed worldwide with increasing solitary and non-spouse households, which could affect social care systems. However, the relationship between these households and disability onset has remained unclear. We examined the relationship between living arrangements and the onset of basic activities of daily living disability in older adults, with a focus on gender differences and cohabitation status of those without a spouse.MethodsData from 6600 men and 6868 women aged 65 years or older without disability were obtained from the Aichi Gerontological Evaluation Study Project in Japan. Onset of disability was followed for 9.4 years. Disability was assessed based on Long-term Care Insurance System registration. A hierarchical Cox proportional hazards model was conducted to examine the risk of living alone and living only with non-spousal cohabitants compared to those living with spouses.ResultsMen living only with non-spousal cohabitants and those living alone were significantly more likely to develop disability after controlling for health and other covariates (hazard ratio = 1.38 and 1.45, respectively), while a significant difference was found only for women living alone (hazard ratio = 1.19). The risk of living with non-spousal cohabitants was marginally stronger in men, indicated by the interaction effect model (p = .08). A series of hierarchical analyses showed that social support exchange explained 24.4% and 15.8% of the excess risk of disability onset in men living alone and those living only with non-spousal cohabitants, respectively. A subsequent analysis also showed that support provision by older adults more greatly explained such excess risk than receiving support from others.ConclusionsOlder men without spouses were more likely to develop disability onset regardless of cohabitants. Health professionals should consider programs that enhance social support exchange, particularly support provision by older adults who are at risk of disability.

A 10-Year Follow-Up Study of Social Ties and Functional Health among the Old: The AGES Project.

In Asian nations, family ties are considered important. However, it is not clear what happens among older people with no such ties. To investigate the association, we used longitudinal data from the Aichi Gerontological Evaluation Study (AGES) project. Functionally independent older people at baseline (N = 14,088) in 10 municipalities were followed from 2003 to 2013. Social ties were assessed by asking about their social support exchange with family, relatives, friends, or neighbors. Cox proportional hazard models were employed to investigate the association between social ties and the onset of functional disability adjusting for age, health status, and living arrangement. We found that social ties with co-residing family members, and those with friends or neighbors, independently protected functional health with hazard ratios of 0.81 and 0.85 among men. Among women, ties with friend or neighbors had a stronger effect on health compared to their male counterparts with a hazard ratio of 0.89. The fact that social ties with friends or neighbors are associated with a lower risk of functional decline, independent of family support, serves to underscore the importance of promoting social ties, especially among those lacking family ties.

Positive affect and incident dementia among the old

Background: We investigated the association between positive affect and incident dementia among the old. Studies have reportedthe role positive affect has on maintaining health. Still, no longitudinal studies have assessed the association between positiveaffect and incident dementia. Methods: We used the Aichi Gerontological Evaluation Study (AGES) data. Participants were older adults (65 +) who did notreceive benefits from Japan’s public Long-Term Care Insurance System at baseline (N = 14,286) in 6 municipalities. They werefollowed from 2003 to 2007 for dementia onset. Dementia onset was determined according to the criteria used in the Long-TermCare Insurance System. Positive affect was assessed by sub-scales of the Geriatric Depression Scale (GDS-15). Cox hazardproportional models stratified by sex were employed to calculate hazard ratios for incident dementia. Results: Of 14,286 participants (6,813 men and 7,473 women), 333 men (4.9%) and 468 women (6.3%) developed dementiaduring the 4 year follow-up. In age adjusted Cox models, positive affect was significantly associated with lower risk of dementiaboth among men and women. Even after adjusting for health status, health behaviors, social engagement, and low education,positive affect persisted as a significant protector against dementia. Conclusions: We observed a protective role of positive affect against cognitive decline. Factors associated with higher positiveaffect scores were healthier life style, social engagement, and physical health. This implies the importance of maintaining suchactivities to promote cognitive health among the old. In doing so, the role of positive affect merits attention.

Criteria for social isolation based on associations with health indicators among older people. A 10-year follow-up of the Aichi Gerontological Evaluation Study

No clear evidence for a cut-off point for social isolation has been established so far. The purpose of this study was to evaluate the criteria for social isolation based on associations with objective health outcomes in a 10-year follow-up study. We performed a prospective study of functionally independent residents aged 65 years or older who lived in six municipalities as part of the Aichi Gerontological Evaluation Study (response rate: 50.4%) that began in 2003. Data on the onset of functional disability, dementia, and death were obtained from municipal databases of the public long-term care insurance system. A total of 12,085 participants were followed up for up to 10 years. We used frequencies of face-to-face and non-face-to-face contact with non-resident children, relatives and friends, or neighbors as indicators of social isolation. The overall frequency of contact with others was categorized from "less than once a month" to "frequently, every day." Cox's proportional hazard model revealed that, after controlling for sex, age, education level, marital status, equivalent household income, need for medical care, self-recognition of forgetfulness, and residential area, the hazard ratios for functional disability (over long-term care level 2), dementia, and premature death increase in those with contact frequency of "less than once a month" were 1.37 (95% confidence interval [CI]: 1.16-1.61), 1.45 (95% CI: 1.21-1.74), and 1.34 (95% CI: 1.16-1.55), respectively. The "from once a month to once a week" frequency was also associated with these health indicators, although the "more than once a week" frequency was not significantly associated with any measured outcome. The prevalence of "less than once a month" contact was 7.4% (men=10.2%, women=4.7%), and this was 15.8% (men=21.2%, women=10.6%) when including those with "less than once a week" contact. These findings suggest that "less than once a week" or "less than once a month" contact with non-cohabitant others are valid operational definitions of social isolation that are closely associated with premature death and other health indicators.

Influence of socioeconomic status on the association between body mass index and cause-specific mortality among older Japanese adults: The AGES Cohort Study

ObjectiveMany studies have suggested a U-shaped curve for the association between body size and mortality risks, i.e., mortality risks increase in those who are both overweight and underweight. The strength of the associations may vary according to socioeconomic statuses (SES), as they determine levels of access to healthcare and psychosocial stresses. We investigated the modifying effects of SES on the relationship between body mass index (BMI) and mortality. MethodWe used prospective cohort data of participants in the Aichi Gerontological Evaluation Study in 2003 (n=14,931), who were 65years or older and physically and cognitively independent at baseline, and residing in eight municipalities in Japan. Data on all-causes mortality and mortality from cancer, cardiovascular disease, and respiratory disease was obtained from municipal government registries. ResultsProportional hazard regression analyses showed that, among men, the associations between overweight (BMI≥25kg/m2) and higher mortality risks by any cause were stronger among lower income groups. Even adjusting for multiple confounding factors, hazard ratios (95% confidence intervals) for mortality by all causes among low income group (household income<1.5 million yen) were 1.96 (1.02–3.73) for overweight compared with BMIs between 23.0 and 24.9, whereas they were 0.94 (0.57–1.38) among men in high income group (income>3 million yen). The modifying effects of income were not marked among women. ConclusionHousehold income, which may directly reflect accessibility to healthcare and psychosocial stress among older Japanese men, may be an important modifying factor in the health risks attributable to overweight.

Social participation and the prevention of functional disability in older Japanese: the JAGES cohort study.

BackgroundWe examined the relationship between incident functional disability and social participation from the perspective of number of types of organizations participated in and type of social participation in a prospective cohort study.MethodThe study was based on the Aichi Gerontological Evaluation Study (AGES) Cohort Study data. We followed 13,310 individuals aged 65 years or older for 4 years. Analysis was carried out on 12,951 subjects, excluding 359 people whose information on age or sex was missing. Social participation was categorized into 8 types.ResultsCompared to those that did not participate in any organizations, the hazard ratio (HR) was 0.83 (95% CI: 0.73–0.95) for participation in one, 0.72 (0.61–0.85) for participation in two, and 0.57 (0.46–0.70) for participation in three or more different types of organizations. In multivariable adjusted models, participation in the following types of organization was protective for incident disability: local community organizations (HR = 0.85, 95% CI: 0.76–0.96), hobby organizations (HR = 0.75, 95% CI: 0.64–0.87), and sports organizations (HR = 0.64, 95% CI: 0.54–0.81).ConclusionSocial participation may decrease the risk of incident functional disability in older people in Japan. This effect may be strengthened by participation in a variety of different types of organizations. Participating in a local community, hobby, or sports group or organization may be especially effective for decreasing the risk of disability.

Social participation and mental health: moderating effects of gender, social role and rurality

BackgroundPrevious studies have reported that older people’s social participation has positive effects on their health. However, some studies showed that the impacts of social participation on health differ by gender. We sought to examine whether the effects of social participation on mental health differ for men and women in a Japanese population. We also examined the moderating influence of social position within the organization as well as urban/rural locality.MethodsWe used two waves of the Aichi Gerontological Evaluation Study’s longitudinal survey, which targeted residents with aged 65 years or over (n = 2,728) in a central part of Japan. The first wave survey was conducted in 2003, and the second wave in 2006. Depressive symptoms of the study participants were assessed using the short version of the Geriatric Depression Scale (GDS-15). A multilevel logistic regression model was used with individual-level as level 1 and the school district-level as level 2.ResultsWe found that higher social participation and performing key roles in the organization had protective effects on depressive symptoms for women. However, there were no main effects of these variables for the mental health of men. We found an interaction between social participation, organizational position, and rural residence among men only. That is, men who occupied leadership positions in organizations reported better mental health, but only in rural areas.ConclusionsOur findings support the notion that increasing the opportunities for social participation improves older people’s heath, especially for women. However, in the rural Japanese context, offering men meaningful roles within organizations may be important.

Social disorganization/social fragmentation and risk of depression among older people in Japan: Multilevel investigation of indices of social distance

Previous studies reported that social disorganization/fragmentation could predict mental well-being of residents in a community. The aim of this study is to examine how area and individual level of social distance could predict likelihood of mental health among older people in Japan. We empirically derived an index of “social distance” by taking averaged differences in sociodemographic characteristics that are income, education, hometown of origin, the duration of residency, and life stage, between the study participants and their neighbors. We used the study participants (n = 9147) from the Aichi Gerontological Evaluation Study, which targeted residents with aged 65 years or over in a central part in Japan. Depressive symptoms of the study participants were assessed using the short version of the Geriatric Depression Scale (GDS-15). We also tested if area-level social capital would moderate the association between social distance and depressive symptoms. Using multilevel analyses, we found that higher social distance from neighbors was associated with increased depressive symptoms, independently of respondents' own values of income and educational attainment. At the individual level, each standard deviation in income-based and education-based social distance was associated with an odds ratio for depressive symptoms of 1.15 (95% CI: 1.01–1.30) and 1.17 (95% CI: 1.03–1.32), respectively. However, the area-aggregated indices of social distance were not associated with depressive symptoms. Additionally, area-level social capital indicating higher levels of trust between neighbors and social participation, buffered the adverse effect of social distance on depressive risk. In an instance of the “dark side” of social capital, we also found that stronger social cohesion increased depressive symptoms for residents whose hometown of origin differed from the communities where they currently resided.

Participation in Sports Organizations and the Prevention of Functional Disability in Older Japanese: The AGES Cohort Study

BackgroundWe sought to examine prospectively the difference in the association between incident functional disability and exercise with or without sports organization participation.MethodsThe study was based on the Aichi Gerontological Evaluation Study (AGES) Cohort Study data. In October 2003, self-reported questionnaires were mailed to 29,374 non-disabled Japanese individuals aged 65 years or older. Of these, 13,310 individuals were introduced to the Study, and they were followed for 4 years. Analysis was carried out on 11,581 subjects who provided all necessary information for the analysis.ResultsAnalysis was carried out on incident functional disability by 4 groups of different combinations of performance of exercise and participation in a sports organization Active Participant (AP), Exercise Alone (EA), Passive Participant (PP) and Sedentary (S). Compared to the AP group, the EA group had a hazard ratio (HR) of 1.29 (1.02–1.64) for incident functional disability. No significant difference was seen with the PP group, with an HR of 1.16 (0.76–1.77). When a measure of social networks was added to the covariates, the HR of the EA group dropped to 1.27 (1.00–1.61), and significant differences disappeared. In contrast, it showed hardly any change when social support was added.ConclusionThe results suggested that, even with a regular exercise habit, incident functional disability may be better prevented when a person participates in a sports organization than when he/she does not. In addition, participation in a sports organization correlates positively with social networks, which may lead to a small decrease in incident functional disability.

Does social capital affect the incidence of functional disability in older Japanese? A prospective population-based cohort study

BackgroundRecent increases in numbers of older people have been accompanied by increases in those with functional disability. No study has examined the association between community social capital and the onset...

Gender differences on the impacts of social exclusion on mortality among older Japanese: AGES cohort study

To evaluate the gender-specific impact of social exclusion on the mortality of older Japanese adults, we performed a prospective data analysis using the data of the Aichi Gerontological Evaluation Study (AGES). In AGES, we surveyed functionally independent residents aged 65 years or older who lived in six municipalities in Aichi prefecture, Japan. We gathered baseline information from 13,310 respondents in 2003. Information on mortality was obtained from municipal databases of the public long-term care insurance system. All participants were followed for up to 4 years. We evaluated social exclusion in terms of the combination of social isolation, social inactivity, and relative poverty. Cox’s proportional hazard model revealed that socially excluded older people were at significantly increased risk (9–34%) for premature mortality. Those with simultaneously relative poverty and social isolation and/or social inactivity were 1.29 times more likely to die prematurely than those who were not socially excluded. Women showed stronger overall impact of social exclusion on mortality, whereas relative poverty was significantly associated with mortality risks for men. If these associations are truly causal, social exclusion is attributable to 9000–44,000 premature deaths (1–5%) annually for the older Japanese population. Health and social policies to mitigate the issue of social exclusion among older adults may require gender-specific approaches.

Association Between Self-Reported Dental Health Status and Onset of Dementia

Studies have shown that people with cognitive impairment have poor dental health. However, the direction of causality remains unknown. This prospective cohort study aimed to determine the association between four self-reported dental health variables and dementia onset in older Japanese people. Analysis was conducted on 4425 residents 65 years or older. Four self-reported dental health variables included the number of teeth and/or use of dentures, ability to chew, presence/absence of a regular dentist, and taking care of dental health. Data were collected using self-administered questionnaires given in 2003. Records of dementia onset during 2003 to 2007 were obtained from municipalities in charge of the public long-term care insurance system. Age, income, body mass index, present illness, alcohol consumption, exercise, and forgetfulness were used as covariates. Dementia onset was recorded in 220 participants. Univariate Cox proportional hazards models showed significant associations between the dental health variables and dementia onset. In models fully adjusted for all covariates, hazard ratios (95% confidence intervals) of dementia onset of respondents were as follows: 1.85 (1.04-3.31) for those with few teeth and without dentures; 1.25 (0.81-1.93) for those who could not chew very well; 1.44 (1.04-2.01) for those who did not have a regular dentist; and 1.76 (0.96-3.20) for those who did not take care of their dental health. Few teeth without dentures and absence of a regular dentist, not poor mastication and poor attitudes toward dental health, were associated with higher risk of dementia onset in the older Japanese cohort even after adjustment for available covariates.

Sex/Gender and Socioeconomic Differences in the Predictive Ability of Self-Rated Health for Mortality

BackgroundStudies have reported that the predictive ability of self-rated health (SRH) for mortality varies by sex/gender and socioeconomic group. The purpose of this study is to evaluate this relationship in Japan and explore the potential reasons for differences between the groups.Methodology/Principal FindingsThe analyses in the study were based on the Aichi Gerontological Evaluation Study's (AGES) 2003 Cohort Study in Chita Peninsula, Japan, which followed the four-year survival status of 14,668 community-dwelling people who were at least 65 years old at the start of the study. We first examined sex/gender and education-level differences in association with fair/poor SRH. We then estimated the sex/gender- and education-specific hazard ratios (HRs) of mortality associated with lower SRH using Cox models. Control variables, including health behaviors (smoking and drinking), symptoms of depression, and chronic co-morbid conditions, were added to sequential regression models. The results showed men and women reported a similar prevalence of lower SRH. However, lower SRH was a stronger predictor of mortality in men (HR = 2.44 [95% confidence interval (CI): 2.14–2.80]) than in women (HR = 1.88 [95% CI: 1.44–2.47]; p for sex/gender interaction = 0.018). The sex/gender difference in the predictive ability of SRH was progressively attenuated with the additional introduction of other co-morbid conditions. The predictive ability among individuals with high school education (HR = 2.39 [95% CI: 1.74–3.30]) was similar to that among individuals with less than a high school education (HR = 2.14 [95% CI: 1.83–2.50]; p for education interaction = 0.549).ConclusionsThe sex/gender difference in the predictive ability of SRH for mortality among this elderly Japanese population may be explained by male/female differences in what goes into an individual's assessment of their SRH, with males apparently weighting depressive symptoms more than females.

Social Determinants of Active Aging: Differences in Mortality and the Loss of Healthy Life between Different Income Levels among Older Japanese in the AGES Cohort Study

We examined the relationship between income, mortality, and loss of years of healthy life in a sample of older persons in Japan. We analyzed 22,829 persons aged 65 or older who were functionally independent at baseline as a part of the Aichi Gerontological Evaluation Study (AGES). Two outcome measures were adopted, mortality and loss of healthy life. Independent variables were income level and age. The occurrence of mortality and need for care during these 1,461 days were tracked. Cox regressions were used to calculate the hazard ratio for mortality and loss of healthy life by income level. We found that people with lower incomes were more likely than those with higher incomes to report worse health. For the overall sample, using the governmental administrative data, the hazard ratios of mortality and loss of healthy life-years comparing the lowest to the highest income level were 3.50 for men and 2.48 for women for mortality and 3.71 for men and 2.27 for women for loss of healthy life. When only those who responded to questions about income on the mail survey were included in the analysis, the relationships became weaker and lost statistical significance.

Dental status and incident falls among older Japanese: a prospective cohort study

ObjectiveTo examine if self-reported number of teeth, denture use and chewing ability are associated with incident falls.DesignLongitudinal cohort study (the Aichi Gerontological Evaluation Study).Setting5 Japanese municipalities.Participants1763 community-dwelling individuals aged 65...

Does walkable mean sociable? Neighborhood determinants of social capital among older adults in Japan

Why are some communities more cohesive than others? The answer to the puzzle has two parts: (a) due to variations in the attributes of residents, and/or (b) due to variations in the attributes of places. However, few studies have sought to examine the community-level determinants of social capital. In the present study, we examined the associations between social capital and different area characteristics: (1) neighborhood walkability, (2) date of community settlement, and (3) degree of urbanization. We based our analysis on 9414 respondents from the Aichi Gerontological Evaluation Study (AGES), conducted in 2003. No significant positive association was found between the walkability score and any of the social capital indices. In contrast, community age and degree of urbanization were associated with many of the social capital indicators, even after controlling for characteristics of the residents. Community social capital thus appears to be more consistently linked to the broader historical and geographic contexts of neighborhoods, rather than to the proximal built environment (as measured by walkability).