The concept of social capital encompasses all relationships and networks among people in a local community or society as a whole. It has been found to be associated with the health and daily living status of people. Furthermore, an association between social capital and cognitive functions among the elderly has been suggested in recent years. However, the number of such reports is very few. Hence, the present study aims to evaluate the relationship between social capital and cognitive functions among the elderly living in a local community in Japan. A questionnaire survey was administered to 192 elderly individuals belonging to 10 neighborhood elderly groups. A regression analysis was conducted to determine the relationship between cognitive functions and the level of engagement with the local community, after adjusting for age, gender, and symptoms of depression. Valid responses were collected from 145 participants (mean age: 75.3 years). An analysis of the data concerning the level of engagement with the local community revealed a significant difference in the cognitive function scores between the group of people who indicated that they had someone they could consult (n = 69) and the group that indicated they had no one to consult (n = 76) (regression coefficient: -0.61, p = 0.0038, 95% confidence interval: -1.02 to -0.20). This result indicates the existence of a significant correlation between social capital and cognitive functions of the elderly living in a local community. In future studies, we need to investigate the same with a larger number of participants from a wider geographical area, and by incorporating more indicators for a comprehensive evaluation of social capital.
The concept of social capital encompasses all relationships and networks among people in a local community or society as a whole. The definition of social capital varies among researchers. However, the following definition proposed by Putnam is used most frequently: “Social capital refers to the features of a social organization, such as trusts, norms, and networks, that can improve the efficacy of the society by facilitating coordinated actions” [
Social capital has been shown to be associated with health status and life expectancy. Kawachi et al. conducted a large-scale survey of the individuals who live in 39 US states and revealed that the risk of perceived poor health increased in individuals living in states with a lower level of social capital [
Previous studies have demonstrated that social capital is correlated not only with physical health, but also with mental health. In a nationwide survey of adults in Russia, social capital was found to be correlated with both physical health and mental health, and the correlation with the latter was found to be even stronger [
Furthermore, in recent years, social capital has been reported to be associated with cognitive functions among the elderly. For instance, Sakamoto et al. conducted a study on the elderly living in a local community who did not need long-term care in their daily life. Their findings revealed that cognitive functions were superior in individuals who were more frequently involved in social activities [
In all the administrative districts (n = 13) of Fujisawa City (population: 423,435; percentage of residents aged 65 years or over: 23.0%, as of April 1, 2015) in the Kanagawa prefecture, we conducted research briefing sessions in the city’s businesses and related organizations in the city (e.g., sessions were conducted in about 150 senior citizens clubs, which were visited by approximately 7800 at that time). Ten organizations for the elderly agreed to participate in this study, and 192 elderly (aged 60 years or more) belonging to these 10 organizations provided consent for participation in this study (62 males and 130 females; mean age: 75.2 years; standard deviation: 6.3 years). A questionnaire survey was then carried out with these participants, from July 2015 to March 2016.
This study was approved by the Ethics Committee of Graduate School of Health Management, Keio University (#2015-16), and it was conducted in compliance with the recommendations of the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research Involving Human Subjects. Additionally, it was registered as a clinical study with the University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR, UMIN000018401).
The investigation covered the participants’ cognitive functions, the degree of relationship with the local community (an element of social capital), and symptoms of depression, which may be associated with cognitive dysfunction).
Cognitive functions were evaluated using the Cognitive Assessment for Dementia, iPad version 2 (CADi2), developed by Yamaguchi et al. (available for free at the Apple Store: https://itunes.apple.com/us/app/cadi/id586052447). The CADi2 is a cognitive function test used as a primary screening tool during health checkups in local communities, and its reliability and validity have been verified [
The degree of relationship between individuals within the community was evaluated using the method employed in a previous study [
Symptoms of depression were investigated using the Japanese version of Zung’s Self-Rating Depression Scale (SDS) [
Age and gender were evaluated as demographic variables.
The data were subjected to a multivariate analysis after the exclusion of missing values (n = 47). A regression analysis was conducted to determine the relationship between cognitive functions and the level of engagement with the local community. The cognitive function level was regarded as the response variable and the social capital level was regarded as the explanatory variable. The depression score (SDS), age, and gender were adjusted as covariates related to cognitive functions. The participants were divided into 2 groups based on having or not having someone to consult, because of the substantial difference of the level of engagement with the local community between the two categories. Statistical analyses were conducted using R version 3.3.3 (R Foundation for Statistical Computing, Vienna, Austria); the level of significance was set at p < 0.05.
Of the elderly who were enrolled in this study (N = 192), 157 participated in the onsite survey that included the administration of the CADi. Valid responses were collected from 145 participants (mean age ± standard deviation [SD]: 75.3 ± 6.3 years). The demographic variables of the participants have been shown in
An analysis of the data regarding the degree of relationship with the local community revealed a significant difference in the cognitive function scores between the group of people who indicated that they had someone they could consult (Category 1, n = 69) and the group that indicated they had no one to consult (Category 2 - 4, n = 76; regression coefficient: −0.61, p = 0.0038, 95% confidence interval: −1.02 to −0.20;
The results of this study indicated that individuals with a deep relationship with the local community had higher cognitive function levels than did individuals without such a relationship. Regarding this relationship, previous studies have demonstrated that an abundance of networks and commitment to social activities were associated with better levels of cognitive functioning [
N (%) | Median (25th - 75th percentile) | |
---|---|---|
Age (in years) | 145 | 75 (71 - 80) |
Gender | ||
Male | 50 (34.5) | - |
Female | 95 (65.5) | - |
Social capital (networks)a | ||
1 | 69 (47.6) | - |
2 | 49 (33.8) | - |
3 | 24 (16.6) | - |
4 | 3 (2.1) | - |
CADi score | 145 | 9 (8 - 10) |
SDS score | 145 | 34 (30 - 40) |
a1: I have someone that I can consult; 2: I have someone that I can chat with; 3: I have someone to exchange greetings with; 4: I am not sociable at all. CADi: Cognitive Assessment for Dementia, iPad Version. SDS: Self-Rating Depression Scale.
Estimate | 95%CI | |
---|---|---|
Social capital (networks) | ||
The kind of relationship with individuals in their community | ||
Having someone to consult (n = 69) | Ref. | - |
Having no one to consult (n = 76) | −0.61 | −1.02 - 0.20 |
A regression analysis was conducted to determine the relationship between cognitive functions and the degree of relationship with the local community after adjusting for age, gender, and SDS score. CI: Confidence Interval, Ref.: Reference, SDS: Self-Rating Depression Scale.
sults of the present study suggest that the depth of an individual’s relationships with others in a given community is also associated with his/her cognitive functions. This association is consistent with the report of Dodge et al., who stated that daily conversations with others could improve the cognitive functions of the elderly [
This study had several other limitations. First, it has been reported previously that the degree of relationship with the local community is also associated with health indicators, in addition to cognitive functions [
Third, although the present study used the depth of the relationship with the local community as an indicator of social capital, the latter is actually known to be composed of trust, norms, and networks [
The results of the present study indicate the existence of a significant correlation between social capital and cognitive functions of the elderly living in a local community. However, the data available are not sufficient to permit generalization of the findings. Future studies need to replicate this study with a larger number of participants from a wider geographical area, and by incorporating other indicators for a comprehensive evaluation of social capital. If the relationship between social capital and cognitive function levels can be further clarified, it will be possible to utilize the findings for helping the elderly lead better and longer lives in the local community, and for devising measures to prevent the onset of dementia.
This work was partly supported by the Comprehensive Research on Aging and Health Science Research Grants for Dementia R & D from the Japan Agency for Medical Research and Development (AMED) and Keio Gijuku Academic Development Funds.
Takechi, S., Yoshimura, K., Oguma, Y., Saito, Y. and Mimura, M. (2017) Relationship between Social Capital and Cognitive Functions among Community-Based Elderly. Advances in Alzheimer’s Disease, 6, 45-51. https://doi.org/10.4236/aad.2017.62004