Cohort profile: the ages 2003 cohort study in Aichi, Japan

Oral status and homebound status: A 6-year bidirectional exploratory prospective cohort study

OBJECTIVES

Little is known about the association between oral status and homebound status, and there is a possibility of a bidirectional relationship between them. In this exploratory prospective cohort study, we examined the association between four oral status measurements and being homebound bidirectionally.

METHODS

We used 2010-2016 panel data gathered from the Japan Gerontological Evaluation Study. All functionally independent participants aged 65 years or older (n = 26,579) were included in this study. Multiple imputation and Poisson regression were used for analyses. We adjusted for age, sex, education, comorbidity, and depressive symptoms.

RESULTS

In the fully adjusted model, the prevalence ratio (PR) of being homebound at follow-up was 1.42 for having <20 remaining teeth, 1.28 for having chewing difficulty, 0.99 for having choking experience, and 0.94 for having dry mouth at baseline. Reversely, being homebound at baseline predicted having chewing difficulty at follow-up (PR = 1.17), while no significant association was demonstrated with having <20 teeth (PR = 1.00), choking experience (PR = 1.06), and dry mouth (PR = 1.02).

CONCLUSION

Chewing difficulty and having <20 remaining teeth predicted homebound status after 6 years. Reversely, homebound status at baseline only predicted having chewing difficulty at follow-up. These findings may help to determine the oral frailty assessment measures for older people.

Factors Associated with Handgrip Strength Among Older Adults in Malaysia

Purpose

Handgrip strength (HGS) is indicative of overall physical health among older adults. A decrease in HGS may be associated with an increased risk of disease. The aim of this study is to determine the factors associated with HGS among older adults in Malaysia.

Patients and Methods

One thousand two hundred four (1204) participants from urban and rural areas in Selangor state, Malaysia, were recruited. Sociodemographic and health-related conditions were gathered through a comprehensive face-to-face interview, followed by HGS assessments by a handgrip dynamometer. Subsequently, multiple linear regression was used to test the main association with the HGS.

Results

A total of 691 participants (57.4%) were male, and 513 (42.6%) were female. Males had a mean HGS of 30.0 (SD 7.53) kg, and females had a mean HGS of 19.4 (SD 5.28) kg. Males’ handgrip strength was significantly reduced with increasing age, physically inactive, and diabetes (all at the level p<0.001) after adjusting for social-demographic characteristics and health-related variables. Meanwhile, for females, the HGS was significantly decreased with age (p<0.001), physically inactive (p<0.001) and hypertension (p=0.03). However, female HGS was positively related to BMI (p<0.001).

Conclusion

The study contributed to a better understanding of factors associated with HGS, and thus, the HGS is recommended as a section in the health evaluation among high-risk older adults as the strategy of disease control and prevention.

Unmet Healthcare Needs Among Elderly Malaysians

Purpose

Older people often have chronic diseases which require a continuity of care over the long term. Countries undergoing population aging need to ensure that older people are receiving the care they need. This study assesses the prevalence of, reasons for, and factors associated with unmet healthcare needs among older people individuals in Malaysia.

Patients and Methods

This cross-sectional study used data collected during 2018–2020 from 1204 older adults aged 60 and older selected from Selangor state, Malaysia. A comprehensive face-to-face interview based on the Bahasa Malaysia version of the Japan Gerontological Evaluation Study (JAGES-BM) questionnaire was administered to gain information on unmet healthcare needs, socioeconomic factors, health-related factors, and measures of function (activities of daily living, depression, visual impairment, hearing impairment, memory impairment, and walking impairment). Multivariate logistic regression was used to analyze factors associated with their unmet healthcare needs.

Results

Overall, the percentage of older people respondents with unmet healthcare needs is 6.6%. The most reported reasons for forgoing or delaying healthcare were lack of knowledge about healthcare and financial barriers to care. The inability to travel alone (adjusted odds ratio [aOR] 2.51), being overweight (aOR 1.88), and having self-reported depression (aOR 2.23) were each associated with a higher likelihood of having unmet healthcare needs in their daily life.

Conclusion

The prevalence of unmet healthcare needs among older people in this part of Malaysia is lower than that reported in some other countries. However, it is possible to further reduce unmet healthcare needs by improving people’s knowledge and attitudes about appropriate healthcare utilization, strengthening financial protection measures and providing support to people at high risk of having unmet healthcare needs.

Community social support and onset of dementia in older Japanese individuals: a multilevel analysis using the JAGES cohort data

OBJECTIVE

Recently, there has been an increase in the number of people with dementia. However, no study has examined the association between community-level social support and the onset of incident dementia using multilevel survival analysis.

DESIGN

A prospective cohort study.

PARTICIPANTS AND SETTING

We analysed data pertaining to 15 313 (7381 men and 7932 women) community-dwelling adults aged 65 years or older who had not accessed long-term care insurance and were living in Aichi Prefecture (seven municipalities) in Japan.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association between community-level social support and onset of incident dementia was examined using the Japan Gerontological Evaluation Study, a prospective cohort study introduced in Japan in 2003. Incident dementia was assessed using Long-term Care Insurance records spanning 3436 days from the baseline survey.

RESULTS

During the 10-year follow-up, the onset of incident dementia occurred in 1776 adults. Among older people, a 1% increase in community-level social support (in the form of receiving emotional support) was associated with an approximately 4% reduction in the risk of developing dementia, regardless of socio-demographic variables and health conditions (HR=0.96; 95% CI=0.94 to 0.99).

CONCLUSIONS

Receiving community-level social support in the form of emotional support is associated with a lower risk of developing incident dementia.

Factors Associated with Happiness among Malaysian Elderly

Happiness is an essential component to experience healthy ageing. Hence, understanding the factors that contribute to happiness is important. This study aimed to determine the factors associated with happiness among the elderly population in Malaysia. In this study, 1204 respondents were recruited from urban and rural areas in Selangor. A face-to-face interview was conducted using the Bahasa Malaysia version of the Japan Gerontological Evaluation Study questionnaire. The inclusion criteria include Malaysians who are 60-years old and above and can converse in the Malaysian language. Those who encounter less than seven scores for the Abbreviated Mental Test were excluded from the study. Among the 1204 respondents, 953 (79.2%) were happy. Sociodemographic characteristics showed that being a men, age of 60 to 74 years, and living in urban areas were significantly associated with happiness. A logistic regression model showed that locality (aOR 1.61), income category (Bottom 40% aOR 0.49; Middle-class group 40% aOR 1.40), social engagement (active aOR 1.77; less active aOR 1.25), receiving emotional support (aOR 2.11) and handgrip strength (aOR 1.02) were significantly associated with happiness. Thus, ensuring the elderly population in receiving emotional support and active social engagement among them can enhance their happiness level.

Factors Associated with the Need for Assistance among the Elderly in Malaysia

The need for assistance among the elderly is rising, which poses challenges for healthcare systems. Thus, this study aims to determine the factors associated with the need for assistance in the daily living activities of Malaysia’s elderly population. A total of 1204 elderly individuals, aged 60 years and above, were recruited. An interview was conducted using the Bahasa Malaysia version of the Japan Gerontological Evaluation Study (JAGES-BM) questionnaire. Overall, 7.7% of the elderly participants required assistance. A logistic regression model showed that difficult financial statuses (aOR 4.56), hearing difficulties (aOR 1.78), and severe limitations in daily activity over the past 6 months (aOR 11.99) were associated with a higher likelihood of needing assistance. In addition, daily activities such as an inability to feed (aOR 8.46), stand without support (aOR 2.06), or walk for 15 min without stopping (aOR 1.99) were significantly associated with the need for assistance. Factors associated with the need for assistance are health status, disability, and the financial status of the elderly. Preventive measures should be included in policies to ensure the sustainability of the care provided to the elderly in terms of promoting healthy ageing and a good quality of life.

Self-Acceptance and Interdependence Promote Longevity: Evidence From a 20-year Prospective Cohort Study

We explored psychosocial pathways to longevity, specifically, the association between psychological well-being and mortality in a 20-year prospective cohort study of 7626 participants. As hypothesized, high self-acceptance and interdependence were associated with decreased mortality risk, controlling for other psychological components (purpose, positive relations, growth, mastery) and potential confounders: personality, depression, self-rated health, smoking status, body mass index (BMI), illness, and demographics. Self-acceptance decreased mortality risk by 19% and added three years of life. Longevity expectation fully mediated the relationship between self-acceptance and mortality. Interdependence decreased mortality risk by 17% and added two years of life. Serenity towards death fully mediated the relationship between interdependence and mortality. This is the first known study to investigate self-acceptance, interdependence, and serenity toward death as promoters of longevity, and distilled the relative contributions of these factors, controlling for covariates-all of which were measured over multiple time points. Theoretically, this study suggests that components of well-being may make meaningful contributions to longevity, and practically recommend that self-acceptance and interdependence could be added to interventions to promote aging health.

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)

OBJECTIVES

Our study aimed to examine the longitudinal association between social participation and both mortality and the need for long-term care (LTC) simultaneously.

DESIGN

A prospective cohort study with 9.4 years of follow-up.

SETTING

Six Japanese municipalities.

PARTICIPANTS

The participants were 15 313 people who did not qualify to receive LTC insurance at a baseline based on the data from the Aichi Gerontological Evaluation Study (AGES, 2003-2013). They received a questionnaire to measure social participation and other potential confounders. Social participation was defined as participating in at least one organisation from eight categories.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes were classified into three categories at the end of the 9.4 years observational period: living without the need for LTC, living with the need for LTC and death. We estimated the adjusted OR (AOR) using multinomial logistic regression analyses with adjustment for possible confounders.

RESULTS

The primary analysis included 9741 participants. Multinomial logistic regression analysis revealed that social participation was associated with a significantly lower risk of the need for LTC (AOR 0.82, 95% CI 0.69 to 0.97) or death (AOR 0.78, 95% CI 0.70 to 0.88).

CONCLUSIONS

Social participation may be associated with a decreased risk of the need for LTC and mortality among elderly patients.

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.

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.

Frequency and pattern of exercise and depression after two years in older Japanese adults: the JAGES longitudinal study

Few have clarified what exercise frequencies and patterns (e.g. alone or with others) are effective for preventing depression in older adults. We examined the relationship between total frequency and/or pattern of exercise and the risk of depression after two years in older Japanese adults. We used a sub-sample of the Japan Gerontological Evaluation Study (JAGES) performed in 2011 and 2013. The sample for analysis was 1,422 adults aged 65 years or older without depression and low physical strength in 2011. All variables were assessed with a questionnaire including the geriatric depression screening scale (GDS-15). Binomial logistic regression analysis was used to examine the relationships between exercise in 2011 and depression in 2013 (0 = non-depression, 1 = depression). The adjusted odds ratio (OR) for later depression was 0.52 (95% confidence intervals: 0.33–0.81) for exercise two or more times a week compared to non-exercisers. The OR for exercisers who exercise with others even a little (Ewo) was 0.53 (0.34–0.84) compared to non-exercisers. Among combinations of frequency and pattern, the OR for Ewo who exercise two or more times a week was 0.40 (0.24–0.68) compared to non-exercisers. Exercising at least twice a week and/or with others may be useful in preventing depression in older adults.

Participation in Community Group Activities Among Older Adults: Is Diversity of Group Membership Associated With Better Self-rated Health?

Background

Participation in community activities (eg, sports and hobby groups or volunteer organizations) is believed to be associated with better health status in the older population. We sought to (1) determine whether a greater diversity of group membership is associated with better self-rated health and (2) identify the key dimension of the membership diversity (eg, gender, residential area, or age).

Methods

We performed a cross-sectional study of 129,740 participants aged 65 years and older who were enrolled in the Japan Gerontological Evaluation Study in 2013. We assessed the diversity of group membership using (1) a continuous variable (range 0–4) accounting for the total degree of each diversity dimension or (2) dummy variables for each dimension. We estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) for better self-rated health according to the diversity of group membership, using Poisson regression and robust variance with multiple imputation, adjusted for other covariates.

Results

The participants involved in social groups with greater diversity had better self-rated health: the PR per one point unit increase in diversity was 1.03 (95% CI, 1.02–1.04). Participation in gender-diverse groups was associated with the best profile of health (PR 1.07; 95% CI, 1.04–1.09).

Conclusions

Among the older population in Japan, higher group diversity is associated with better self-rated health. Gender is the key dimension of diversity that is associated with better self-rated health.

Social and Behavioural Determinants of the Difference in Survival among Older Adults in Japan and England

BACKGROUND

A rapidly ageing population presents major challenges to health and social care services. Cross-country comparative studies on survival among older adults are limited. In addition, Japan, the country with the longest life expectancy, is rarely included in these cross-country comparisons.

OBJECTIVE

We examined the relative contributions of social and behavioural factors on the differences in survival among older people in Japan and England.

METHODS

We used data from the Japan Gerontological Evaluation Study (JAGES; n = 13,176) and the English Longitudinal Study of Ageing (ELSA; n = 5,551) to analyse all-cause mortality up to 9.4 years from the baseline. Applying Laplace regression models, the 15th survival percentile difference was estimated.

RESULTS

During the follow-up, 31.3% of women and 38.6% of men in the ELSA died, whereas 19.3% of women and 31.3% of men in the JAGES died. After adjusting for age and baseline health status, JAGES participants had longer survival than ELSA participants by 318.8 days for women and by 131.6 days for men. Family-based social relationships contributed to 105.4 days longer survival in JAGES than ELSA men. Fewer friendship-based social relationships shortened the JAGES men's survival by 45.4 days compared to ELSA men. Currently not being a smoker contributed to longer survival for JAGES women (197.7 days) and ELSA men (46.6 days), and having lower BMI reduced the survival of JAGES participants by 129.0 days for women and by 212.2 days for men.

CONCLUSION

Compared to participants in England, Japanese older people lived longer mainly because of non-smoking for women and family-based social relationships for men. In contrast, a lower rate of underweight, men's better friendship-based social relationships, and a lower smoking rate contributed to survival among participants in England.

An additive effect of leading role in the organization between social participation and dementia onset among Japanese older adults: the AGES cohort study

Background

Several previous studies reported social participation may reduce the incident of dementia; therefore, the type of positions held in the organization may relate to dementia onset. However, this hypothesis remains largely unknown. The purpose of the present study was to examine the additive effect of a leadership position in the organization on dementia onset and social participation among elderly people in a local community, according to data from a Japanese older adults cohort study.

Methods

Of 29,374 community-dwelling elderly, a total of 15,313 subjects responded to the baseline survey and were followed-up from November 2003 to March 2013. To evaluate the association between dementia onset and social participation as well as the role in the organization, we conducted Cox proportional hazard regression analysis with multiple imputation by age group (aged 75 years older or younger). The dependent variable was dementia onset, which was obtained from long-term care insurance data in Japan; independent variables were social participation and the role in the organization to which they belonged (head, manager, or treasurer). Covariates were sex, age, educational level, marriage status, job status, residence status, alcohol consumption, smoking status, and walking time, instrumental activities of daily living, depression, and medical history.

Results

During the follow-up period, 708 young-old elderly people (7.7%) and 1289 old-old elderly people (27.9%) developed dementia. In young-old elderly, relative to social non-participants, adjusted Hazard Ratio (HR) for dementia onset for participants (regular members + leadership positions) was 0.75 (95% confidence interval (CI), 0.64–0.88). Relative to regular members, adjusted HR for dementia onset for non-participants was 1.22 (95% CI, 1.02–1.46), for leadership positions 0.81 (95% CI, 0.65–0.99). The results for old-old elderly participants did not show that any significantly adjusted HR between dementia onset and social participation, the role in the organization.

Conclusions

In young-old elderly people, social participation might have a positive effect on dementia onset, and holding leadership positions in organization could lead to a decrease in risk of dementia onset by almost 20% than regular members.

Electronic supplementary material

The online version of this article (10.1186/s12877-017-0688-9) contains supplementary material, which is available to authorized users.

Influence of social relationship domains and their combinations on incident dementia: a prospective cohort study

Background

Social relationships consist of mutually related but distinct dimensions. It remains unclear how these domains independently contribute to incident dementia. This large-scale, prospective cohort study examines associations between the social relationship domains as well as their combinations and incident dementia among community-dwelling older adults.

Methods

We analysed data from 13 984 community-dwelling adults aged 65+ without long-term care needs living in Aichi prefecture in Japan. Incident dementia was assessed based on the Long-term Care Insurance records, followed for 3436 days from the baseline survey conducted in 2003. Three social relationships domains (social support, social networks and social activities) were further divided into a total of eight subdomains. A social relationship diversity score was calculated using the social relationship domains which were significantly related to incident dementia.

Results

A Cox proportional hazards model showed that being married, exchanging support with family members, having contact with friends, participating in community groups and engaging in paid work were related to a lower likelihood of developing incident dementia, controlling for covariates and other social relationship domains. The diversity scores, ranging from 0 to 5, were linearly associated with incident dementia (p<0.001), and those who scored highest were 46% less likely to develop incident dementia compared with those in the lowest category.

Conclusions

Our findings revealed five social relationship subdomains which were negatively related to incident dementia, suggesting that dementia may potentially be prevented by enhancing these social relationships. Future studies should examine independent pathways between each social relationship domain and incident dementia.

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.

Relationships among sense of coherence, oral health status, nutritional status and care need level of older adults according to path analysis

AIM

Sense of coherence (SOC) is a measurement of ability of an individual to cope with psychological stress and remain in good health. The aim of the present study was to examine the relationships among SOC score, oral health status, nutritional status and care need level of older adults using path analysis.

METHODS

We enrolled 53 older adults (17 men and 36 women) who were attending a day care service (mean age 80.4 ± 6.5 years). SOC was assessed using a 13-item, seven-scale instrument. Oral health status (number of present teeth, denture use) and nutritional status (assessed with Mini-Nutritional Assessment Short-Form) were also evaluated. Path analysis was used to examine the relationship of SOC with other related factors, including care need level.

RESULTS

The mean SOC score was 57.0 ± 13.9. Mini-Nutritional Assessment Short-Form results showed that one participant (1.8%) was malnourished, 26 (49.1%) were at risk of malnutrition and 26 (49.1%) had normal nutritional status. Participants with high SOC scores showed a strong positive attitude, had a relatively large number of teeth, were in good nutritional condition and showed low care need levels.

CONCLUSIONS

The present results showed that maintaining a high SOC level and good oral health help to reduce care need levels in older adults, and also prevent a worsening of their nutritional condition. Geriatr Gerontol Int 2017; 17: 2083-2088.

Neighborhood Characteristics and Cardiovascular Risk among Older People in Japan: Findings from the JAGES Project

Previous studies have found an association between neighborhood characteristics (i.e., aspects of the physical and social environment) and the incidence of cardiovascular disease (CVD) and elevated CVD risk. This study investigated the relationship between neighborhood characteristics and CVD risk among older people in Japan where research on this association is scarce. Data came from the Japan Gerontological Evaluation Study project; questionnaire data collected from 3,810 people aged 65 years or older living in 20 primary school districts in Aichi prefecture, Japan, was linked to a computed composite CVD risk score based on biomarker data (i.e., hemoglobin A1c, systolic blood pressure, diastolic blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and estimated glomerular filtration rate). A sex-stratified multilevel linear regression analysis revealed that for male participants, living in neighborhoods with a higher perceived occurrence of traffic accidents and reduced personal safety was associated with an elevated CVD risk (coefficient = 1.08 per interquartile range increase, 95% confidence interval [CI] = 0.30 to 1.86) whereas males living in neighborhoods with a higher perceived proximity of exercise facilities had a lower risk (coefficient = −1.00, 95% CI = −1.78 to −0.21). For females, there was no statistically significant association between neighborhood characteristics and CVD risk. This study suggests that aspects of the neighborhood environment might be important for CVD morbidity and mortality in Japan, particularly among men.

Social participation and the onset of functional disability by socioeconomic status and activity type: The JAGES cohort study

The impact of social participation on older adults' health may differ by individual socioeconomic status (SES). Consequently, we examined SES effect modification on the associations between types of social activity participation and incident functional disability. Cohort data from the 2003 Japan Gerontological Evaluation Study (JAGES) was utilized. This included individuals who were aged 65 or older and functionally independent at baseline. Analysis was carried out on 12,991 respondents after acquisition of information about their long-term care (LTC) status in Japan. Incident functional disability was defined based on medical certification and LTC information was obtained from municipal insurance databases. Cox proportional hazard regression was conducted for analysis. Results indicated that participants in a sport (hazard ratio [HR]: 0.66; 95% confidence interval [CI]: 0.51, 0.85) or hobby group (HR: 0.69; 95% CI: 0.55, 0.87), or who had a group facilitator role (HR: 0.82; 95% CI: 0.66, 1.02) were less likely to be disabled. While men with 13 or more years of education were less likely to become disabled if they held facilitator roles, this association was weak among men with 0-5years of education (HR of interaction term between 0 and 5years of education and facilitator role dummy variable=3.95; 95% CI: 1.30, 12.05). In conclusion, the association between group participation and smaller risk of the functional disability was stronger among highly educated older adults. Intervention programs promoting social participation should consider participants' socioeconomic backgrounds.

Social participation and mortality: does social position in civic groups matter?

BACKGROUND

Social participation is known to predict longevity. However, little is known about the effect of social participation according to an individual's position in civic groups. We evaluated the influence of social position on mortality, using data from a large cohort of Japanese older adults (the AGES cohort).

METHODS

Of 14,804 individuals aged 65 years and older enrolled in the AGES, 14,286 individuals were followed up for approximately 5 years from 2003 to 2008. We performed inverse probability of treatment weighted (IPTW) Cox proportional hazards regression with multiple imputation of missing values to compute hazard ratios (HR) for all-cause mortality according to the individual's position in the community organization(s) to which they belonged. We examined participation in the following civic groups: neighborhood association/senior citizen club/fire-fighting team, religious group, political organization or group, industrial or trade association, volunteer group, citizen or consumer group, hobby group, and sports group or club. The values for IPTW were computed based on demographic variables, socioeconomic status, and self-reported medical condition.

RESULTS

During 22,718 person-years of follow-up for regular members of community groups and 14,014 person-years of follow-up for participants in leadership positions, 479 deaths and 214 deaths were observed, respectively. Relative to regular members, crude HR for all-cause mortality for occupying leadership positions (e.g. president, manager, or having administrative roles) was 0.72 (95 % CI:0.62-0.85). The IPTW-HR was 0.88 (95 % CI: 0.79-0.99) for participants occupying leadership positions.

CONCLUSIONS

Holding leadership positions in community organization(s) may be more beneficial to health than being regular members.

Does poor dental health predict becoming homebound among older Japanese?

Background

Being homebound is an important risk factor of functional disability in older people. There is a possibility of bidirectional relationship between homeboundness and dental health. This prospective cohort study examined the association of dental health, which includes social function, on homeboundness in the future.

Methods

The participants were ≥ 65 years, responded to two postal surveys conducted in 2006 and 2010, and were not homebound at baseline. Logistic regression analysis was used to estimate the odds ratios for homeboundness, defined as going out of one’s home less than once weekly. Self-reported baseline dental status was used as the main predictor. Age, sex, marital status, educational attainment, income, comorbidity, depression, walking time, living alone, and area of residence were used as covariates.

Results

Among 4390 non-homebound respondents, 7.4 % were homebound four years later. The proportions of homebound respondents with < 20 teeth without dentures, < 20 teeth with dentures, and ≥ 20 teeth were 9.7, 8.8, and 4.4 %, respectively. The odds for being homebound in the 65–74-year age group, adjusted for covariates, was 1.78 (95 % CI: 1.01–3.13; p < 0.05) times higher for respondents with < 20 teeth and no dentures than that for respondents with ≥ 20 teeth. Among the participants in the ≥ 75-year age group, a significant association of homeboundness and dental health was not observed.

Conclusions

Among the young-old population, poor dental health predicted future onset of homeboundness, while depressive symptoms did not show any significant association.

Relative deprivation in income and mortality by leading causes among older Japanese men and women: AGES cohort study

Background

Relative deprivation of income is hypothesised to generate frustration and stress through upward social comparison with one's peers. If psychosocial stress is the mechanism, relative deprivation should be more strongly associated with specific health outcomes, such as cardiovascular disease (compared with other health outcomes, eg, non-tobacco-related cancer).

Methods

We evaluated the association between relative income deprivation and mortality by leading causes, using a cohort of 21 031 community-dwelling adults aged 65 years or older. A baseline mail-in survey was conducted in 2003. Information on cause-specific mortality was obtained from death certificates. Our relative deprivation measure was the Yitzhaki Index, derived from the aggregate income shortfall for each person, relative to individuals with higher incomes in that person's reference group. Reference groups were defined according to gender, age group and same municipality of residence.

Results

We identified 1682 deaths during the 4.5 years of follow-up. A Cox regression demonstrated that, after controlling for demographic, health and socioeconomic factors including income, the HR for death from cardiovascular diseases per SD increase in relative deprivation was 1.50 (95% CI 1.09 to 2.08) in men, whereas HRs for mortality by cancer and other diseases were close to the null value. Additional adjustment for depressive symptoms and health behaviours (eg, smoking and preventive care utilisation) attenuated the excess risks for mortality from cardiovascular disease by 9%. Relative deprivation was not associated with mortality for women.

Conclusions

The results partially support our hypothesised mechanism: relative deprivation increases health risks via psychosocial stress among men.

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

BACKGROUND

We 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.

METHOD

The 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.

RESULTS

Compared 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).

CONCLUSION

Social 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.

Does social participation improve self-rated health in the older population? A quasi-experimental intervention study

Social participation has been linked to healthy aging and the maintenance of functional independence in older individuals. However, causality remains tenuous because of the strong possibility of reverse causation (healthy individuals selectively participate in social activities). We describe a quasi-experimental intervention in one municipality of Japan designed to boost social participation as a way of preventing long-term disability in senior citizens through the creation of 'salons' (or community centers). In this quasi-experimental intervention study, we compared 158 participants with 1391 non-participants in salon programs, and examined the effect of participation in the salon programs on self-rated health. We conducted surveys of community residents both before (in 2006) and after (in 2008) the opening of the salons. Even with a pre/post survey design, our study could be subject to reverse causation and confounding bias. We therefore utilized an instrumental variable estimation strategy, using the inverse of the distance between each resident's dwelling and the nearest salon as the instrument. After controlling for self-rated health, age, sex, equivalized income in 2006, and reverse causation, we observed significant correlations between participation in the salon programs and self-rated health in 2008. Our analyses suggest that participation in the newly-opened community salon was associated with a significant improvement in self-rated health over time. The odds ratio of participation in the salon programs for reporting excellent or good self-rated health in 2008 was 2.52 (95% CI 2.27-2.79). Our study provides novel empirical support for the notion that investing in community infrastructure to boost the social participation of communities may help promote healthy aging.

Participation in sports organizations and the prevention of functional disability in older Japanese: the AGES Cohort Study

BACKGROUND

We sought to examine prospectively the difference in the association between incident functional disability and exercise with or without sports organization participation.

METHODS

The 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.

RESULTS

Analysis 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.

CONCLUSION

The 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.

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.

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: a 4-year prospective cohort study of older Japanese adults from the Aichi Gerontological Evaluation Study (AGES) Project

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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

Background

Studies 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 Findings

The 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).

Conclusions

The 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.

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

OBJECTIVE

To examine if self-reported number of teeth, denture use and chewing ability are associated with incident falls.

DESIGN

Longitudinal cohort study (the Aichi Gerontological Evaluation Study).

SETTING

5 Japanese municipalities.

PARTICIPANTS

1763 community-dwelling individuals aged 65 years and older without experience of falls within the previous year at baseline.

MAIN OUTCOME MEASURES

Self-reported history of multiple falls during the past year at the follow-up survey about 3 years later. Baseline data on the number of teeth present and/or denture use and chewing ability were collected using self-administered questionnaires. Logistic regression analyses controlled for sex, age, functional disability during follow-up period, depression, self-rated health and educational attainment.

RESULTS

86 (4.9%) subjects reported falls at the follow-up survey. Logistic regression models fully adjusted for all covariates showed that subjects having 19 or fewer teeth but not using dentures had a significantly increased risk for incident falls (OR 2.50, 95% CI 1.21 to 5.17, p=0.013) compared with those having 20 or more teeth. Among subjects with 19 or fewer teeth, their risk of falls was not significantly elevated so long as they wore dentures (OR 1.36, 95% CI 0.76 to 2.45, p=0.299). No significant association was observed between chewing ability and incident falls in the fully adjusted model.

CONCLUSIONS

Having 19 or fewer teeth but not using dentures was associated with higher risk for the incident falls in older Japanese even after adjustment for multiple covariates. Dental care to prevent tooth loss and denture treatment for older people might prevent falls, although the authors cannot exclude the possibility that the association is due to residual confounding.

Association between dental status and incident disability in an older Japanese population

OBJECTIVES

To determine the association between dental health status and onset of functional disability in older Japanese people.

DESIGN

Prospective cohort study.

SETTING

Six Japanese municipalities.

PARTICIPANTS

Four thousand four hundred twenty-five community-dwelling individuals aged 65 and over.

MEASUREMENTS

The outcome measure was the onset of functional disability based on public records of people receiving long-term care insurance benefits, determined through a standardized multistep assessment of functional and cognitive impairment including a personal interview and an examination by a physician. Disability data were analyzed for 4,425 respondents during 2003 to 2007. Self-reported number of remaining teeth and eating ability were used as measures of dental health status. Age, sex, body mass index, self-rated health, present illness, smoking, alcohol, exercise, and equivalent income were used as covariates.

RESULTS

In the age- and sex-adjusted Cox proportional hazard models, there were significant associations between number of remaining teeth, eating ability, and onset of disability. After adjusting for sociodemographic, behavioral, and health status variables, respondents with 19 or fewer teeth had a significant 1.21 (95% confidence interval = 1.06-1.40) times higher hazard ratio for the onset of functional disability. In contrast, eating ability was not significantly associated with the onset of disability.

CONCLUSION

Poor dental status was associated with a higher risk of onset of functional disability in older Japanese people. Sociodemographic, behavioral, and health status covariates explained the association between eating ability and onset of disability.

Scale development of health status for secondary data analysis using a nationally representative survey

OBJECTIVES

Scale development of health-related quality of life (HRQOL) measures, including physical and mental health measures, among public datasets from Japan is needed for comparative studies on health conditions among different age, gender, and socio-economic subgroups. Multi-attributable scales of continuous/discrete variables on HRQOL could be more flexible for different kinds of epidemiologic and socio-econometric studies rather than single-item measures. The objectives of this study were to create multi-dimensional scales for physical, mental, and summary health measures and to describe the age-related trends of these scales in Japan.

METHODS

We utilized data from the 2007 Comprehensive Survey of the Living Conditions of People on Health and Welfare (LCPHW: Kokumin Seikatsu Kiso Chosa) (n = 383,745) to measure physical health (0 = worst score, 16 = best score) by summarizing four items: general health status, bedridden status/mobility, self-care/usual activities, and pain (0 = worst score, 4 = best score for each item). Mental health was measured using a Japanese version of K6 (0 = worst score, 4 = best score, modified from original version in which 24 = worst score and 0 = best score). We then created a summary health scale using the simple sum of physical and mental health (0 = worst score, 20 = best score). The reliability and validity of the scales were evaluated and their age-related trends described.

RESULTS

The internal consistency reliability of the physical and summary health scales was not sufficiently high (Cronbach's α = 0.64 and 0.67, respectively) and the age-related trend was smooth and monotonous. The internal consistency reliability of the mental health scale (K6) was high (Cronbach's α = 0.90), while the age-related trend peaked at age 65-74 years.

CONCLUSIONS

While K6 was a measure with high reliability for describing mental health, use of the physical and summary health scale in the Japanese population requires further discussion. Additional validation tests of the summary scales also need to be performed, in which our methodology is applied to other data sets that include strict diagnostic results based on a structural interview.

Relationship between prevalence of childhood obesity in 17-year-olds and socioeconomic and environmental factors: prefecture-level analysis in Japan

To investigate the association between childhood obesity and neighborhood-level socio-economic and environmental factors in Japan. The prevalence of childhood obesity in 2008 was obtained from annual reports of the School Health Survey. The following 12 factors were publicly available: income per person, ratio of people completing up to college or university education, population density, total length of roads per square kilometer, number relative to the population of food and drink stores, restaurants, large-scale retail stores, convenience stores, passenger cars, traffic accidents, criminal offenses, and death by accidents. The ratio of people completing up to college or university education was inversely associated with obesity in boys and girls. No association was found between obesity and the other factors examined. An inverse association was shown between educational level and childhood obesity in both boys and girls. Further studies integrating associations between childhood obesity and neighborhood-level factors are needed.

Oral health and cancer, cardiovascular, and respiratory mortality of Japanese

Cardiovascular diseases, cancer, and respiratory disease are major causes of death in developed countries. No study has simultaneously compared the contribution of oral health with these major causes of death. This study examined the association between oral health and cardiovascular diseases, cancer, and respiratory mortality among older Japanese. Self-administered questionnaires were mailed to participants in the Aichi Gerontological Evaluation Study (AGES) Project in 2003. Mortality data were analyzed for 4425 respondents. Three categories of oral health were used: 20 or more teeth, 19 or fewer teeth and eat everything, 19 or fewer teeth and eating difficulty. Sex, age, body mass index (BMI), self-rated health, present illness, exercise, smoking, alcohol, education, and income were used as covariates. During 4.28 years' follow-up, 410 people died, 159 from cancer, 108 of cardiovascular diseases, and 58 of respiratory disease. Multivariate adjusted Cox proportional hazard models showed that, compared with the respondents with 20 or more teeth, respondents with 19 or fewer teeth and with eating difficulty had a 1.83 and 1.85 times higher hazard ratio for cardiovascular disease mortality and respiratory disease mortality, respectively. There was no significant association with cancer mortality. Oral health predicted cardiovascular and respiratory disease mortality but not cancer mortality in older Japanese.

Assessing the association between all-cause mortality and multiple aspects of individual social capital among the older Japanese

Background

Few prospective cohort studies have assessed the association between social capital and mortality. The studies were conducted only in Western countries and did not use the same social capital indicators. The present prospective cohort study aimed to examine the relationships between various forms of individual social capital and all-cause mortality in Japan.

Methods

Self-administered questionnaires were mailed to subjects in the Aichi Gerontological Evaluation Study (AGES) Project in 2003. Mortality data from 2003 to 2008 were analyzed for 14,668 respondents. Both cognitive and structural components of individual social capital were collected: 8 for cognitive social capital (trust, 3; social support, 3; reciprocity, 2) and 9 for structural social capital (social network). Cox proportional hazard models stratified by sex with multiple imputation were used. Age, body mass index, self-rated health, current illness, smoking history, alcohol consumption, exercise, equivalent income and education were used as covariates.

Results

During 27,571 person-years of follow-up for men and 29,561 person-years of follow-up for women, 790 deaths in men and 424 in women were observed. In the univariate analyses for men, lower social capital was significantly related to higher mortality in one general trust variable, all generalised reciprocity variables and four social network variables. For women, lower social capital was significantly related to higher mortality in all generalised reciprocity and four social network variables. After adjusting for covariates, lower friendship network was significantly associated with higher all-cause mortality among men (meet friends rarely; HR = 1.30, 95%CI = 1.10-1.53) and women (having no friends; HR = 1.81, 95%CI = 1.02-3.23). Among women, lower general trust was significantly related to lower mortality (most people cannot be trusted; HR = 0.65, 95%CI = 0.45-0.96).

Conclusions

Friendship network was a good predictor for all-cause mortality among older Japanese. In contrast, mistrust was associated with lower mortality among women. Studies with social capital indices considering different culture backgrounds are needed.