1. Background

In 2017, the number of elderly people aged 65 or older in South Korea had reached 13.8% of the total population, and the proportion of elderly population is estimated to reach 47.7% by 2045[1]. This increase in the elderly population leads to a rise in social burdens such as an increase in the cost of managing chronic degenerative diseases, and the importance of health care services for the elderly in the community is being increased. Aging process causes physical deterioration and chronic degenerative diseases that require continuous management such as long-term uses of health care and social welfare services, so if the elderly maintain a healthy and independent life in the community, it can reduce social burdens [2].

For the elderly, health status is a major factor influencing the quality of life, and it is recognized as a result of interaction of various factors such as socioeconomic status, living environment, and health promoting behaviors. The subjective health status of the elderly reflects the multiple dimensions of health and is a predictor of health status widely used worldwide. In a previous study in Korea [2], the subjective health status of the elderly in the community was assessed as ‘somewhat poor’, and the proportion of the elderly who assessed themselves as ‘not healthy’ was more than twice that of those who rated themselves as ‘healthy’[3]. In a comparative study between countries [4], the elderly in Korea showed a significantly more negative evaluation of their health status than the elderly in Germany, Sweden and Italy. It is known that the subjective health status of the elderly in the community is affected by sociodemographic characteristics such as age, gender, economic status and health-related characteristics such as regular excercise, the number of comorbidities and pain [5, 6]. In particular, physical activity as a health-promoting behavior of the elderly is an enhancing factor to prevent degenerative diseases and improve the quality of life. The importance of physical activity is also emphasized as one of the priority tasks in the “4th Health Plan 2020”. Physical activity of moderate intensity reduces the mortality due to cardiovascular disease and it reduces the morbidity of chronic diseases such as hypertension, diabetes, and colorectal cancer. On top of the that, It helps to maintain or improve independence and cognitive functioning [7].

According to the 2017 Korea Statistics on the Aged [1], only 46.4% of the elderly aged 65 years or over perform regular exercise, including walking, and this shows that elderly people living in community do not perform proper physical activity. In order to actually enhance health status and health-promoting behaviors such as physical activity in the elderly living in the community, it is necessary to identify influencing factors and to establish an intervention strategy based on them.

In addition to the sociodemographic factors and health-related characteristics, recent studies showed that social capital is a factor significantly influencing the health status of the elderly living in the community [8, 9]. Social capital is a concept that encompasses the attributes of intangible assets in social networks and includes various elements such as trust, reciprocal relationships among community residents, social support and networks [10, 11]. The core components of social capital are social trust and social participation [12], and trust in neighbors and participation in social gatherings are the most important factors for elderly people. As elderly people tend to perform most of their daily activities in their residential areas, they have the environmental characteristic that inhibits the formation of a wide variety of relationships [13], and elderly people need voluntary social participation through mutual exchange with their neighbors. When an elderly person trusts someone or participates in social gatherings, the influence of neighborhood in the community plays an important role [14]. Considering that elderly people are vulnerable due to physical aging, the loss of social roles due to retirement, chronic diseases, and economic challenges, these characteristics of elderly people are more easily exposed to socioenvironmental factors, and thus social interventions are further necessitated [15].

The recent trends in the health and welfare policies for older people emphasize the concept of “Aging in place” and “Age-friendly community”[16], which mean that it is important to ensure that they can continue to live in the community by maintaining and promoting the health of the elderly. The elderly tend to have a strong attachment to familiar places and tend to want to live in the community where they have lived independently rather than living in long-term care facilities. In addition, the health status of the elderly is an important factor for their continuous residence in the community [13].

Social capital is known to affect health through a variety of paths, such as enhancing social support and self-efficacy, improving access to community health care services, health-promoting behaviors, and sharing health information [17]. However, there is still a lack of studies on the effects of social capital on the health status of the elderly in Korea. If social capital is a factor affecting the health of elderly people through various paths, it is important to establish a basis for community-based nursing interventions and health policies that take social capital into account. Therefore, the purpose of this study was to investigate the effect of social capital on the subjective health status of elderly people living in the community and to provide preliminary data for the development of health promotion programs and policies for elderly people living in the community.

2. The Conceptual Framework and Hypothetical Path Model

The conceptual framework of this study was set up to identify the path through which social capital affects physical activity and subjective health status in elderly people living in the community. Therefore, the conceptual framework for the model of the factors affecting the subjective health status of elderly people living in the community was set up based on the neighborhood resource-based theory of social capital for health proposed by Carpiano [18] through a literature review of the studies of subjective health status of the elderly.

1. Study design

This cross-sectional study used secondary data from the 2014 Seoul Survey. We constructed a path model for the paths through which social capital affects the subjective health status of the elderly living in the community and examine the hypothesized path model.

2. Participants

In this study, We utilized the raw data of the 2014 Seoul Survey [19]. As for the Seoul Survey, samples are extracted by stratified cluster sampling based on the district and housing type. The 2014 Seoul Survey was conducted by the household interview survey with household heads and household members aged 15 years or older of the selected households residing in Seoul. Among a total of 45,497 persons who were surveyed in 2014, 4,578 elderly people aged 65 years or older were included in this study for final analysis.

3. Measures

The factors influencing the subjective health status of the elderly were selected through a literature review. The selected variables are as follows:

4. Data Collection and Ethical Consideration

The Seoul Survey is conducted annually by the Seoul Metropolitan Government to analyze the demographic structure and characteristics of Seoul and to utilize it as a basis for municipal administration and policy establishment. The survey period was from October 1 to October 31, 2014 and an additional survey was conducted from November 1 to November 17, 2014. The surveys were conducted in such a way that trained interviewers directly visited the selected households and interviewed them individually. The raw data of the Seoul Survey is public data available freely online for which free use is permitted, including the use or modification of it of commercial purposes and the creation of derivative works, if the author and source are indicated. The raw data for this study was downloaded for analysis through the Seoul Open Data Plaza (http://data.seoul.go.kr/)[19].

5. Data Analysis

The data of this study were analyzed using SPSS/WIN 21.0 and IBM AMOS 23.0 program. The specific analysis method is as follows. Standardized weights were applied to the 2014 Seoul Survey in consideration of the extraction rate and response rate so that the sample that participated in the survey could represent the population of Seoul. The real numbers, percentages, means, and standard deviations for general characteristics of the participants and measured variables were described, and the kurtosis and skewness were calculated to test the normality of the measured variables. The correlation between the measured variables was analyzed by Pearson's correlation coefficient. The model fit was evaluated by the absolute fit index (χ²), the goodness of fit index (GFI), the adjusted goodness index (AGFI), the comparative fit index (CFI), and the root mean squared error of approximation (RMSEA), which is less sensitive to the size of the sample and reflects the parsimony of the model. To test the validity for the path of the model, the parameters were estimated by the maximum likelihood method, and the statistical significance of the indirect effects was analyzed by the bootstrapping method.

1. General Characteristics

The general characteristics of the participants are shown in Table 1. The mean age of the participants was 70.98±5.37 years, and the number of women among them was 2,349 (54.3%), which was higher than that of men. For the marital status, 3,089 (58.3%) living with the spouse. In terms of the education level, 1,714 participants (35.7%) were high school graduates, and regarding the perceived socioeconomic position, 3,542 participants (74.6%) rated their socioeconomic position as middle. 3,111 people (67.9%) were unemployed, and 2,675 people (58.3%) had religion. 2,459 people (41.7%) responded that the number of family members including the participant was two. As for housing type, 2,479 people (55.9%) lived in apartment house. Regarding the type of housing tenure, 3,264 people (62.1%) resided in owner-occupied dwelling. For the level of satisfaction for the neighborhood green area environment, 2,315 people (51.4%) were Neutral and for the level of satisfaction for the neighborhood walking environment, 2,444 people (51.4%) were satisfied.

Table 1 General Characteristics of Participants (N=4,578†) Click for larger image

2. Descriptive Statistics and Correlation Matrix of Measured Variables

Table 2 shows the results of analysis of the correlation matrix between measured variables and the mean and standard deviation of each variable for verifying the hypothetical path model assumed in this study. The kurtosis and skewness of all variables did not exceed an absolute value of 2.0, so normality was satisfied [20], indicating that there was a statistically significant correlation between all variables. As a result of the multicollinearity test, the correlation coefficient between all variables did not exceed the standard value of .60, there was no variable with the tolerance value of 0.1 or lower, and there was no variable with the Variation Inflation Factor (VIP) of more than 10, so multicollinearity between independent variables could be excluded [20]. The mean scores for the variables were 3.31±0.81 points on a 5-point scale for social trust, 1.22±1.06 points on a 11-point scale for social participation, 2.25±1.11 points on a 4-point scale for physical activity, and 5.94±1.84 points on a 11-point scale for subjective health status, respectively.

Table 2 Correlation Coefficient‡, Mean and Standard Deviation‡ of Study Variables (N=4,578†) Click for larger image

3. Model Fit Tests of the Hypothetical Path Model

2) Parameter estimation and significance of the path model

Figure 1 shows the path diagram based on the standardized path parameters of the path model in this study. Among the path parameters of the path model, the path that had a direct significant effect on social participation was social trust (β=.01, p<.001), and the path that had a direct significant influence on physical activity was social participation (β=.25, p<.001). The paths which had a direct significant effect on subjective health status were social participation (β=.25, p<.001) and physical activity (β=.08, p<.001).

Figure 1 Hypothetical path model diagram. Click for larger image

4. Modification of the Hypothetical Path Model

2) Parameter estimation and significance of the modified path model

Figure 2 shows the modified path model based on the standardized path parameters. In the path parameters of the modified path model, the path that directly affected social participation was social trust (β=.01, p<.001), and the path that directly affected physical activity was social participation (β=.25, p<.001). The paths that directly affected subjective health status were found to be social participation (β=.24, p<.001) and physical activity (β=.08, p<.001).

Figure 2 Modified path model diagram. Click for larger image

3) Analysis the modified path model

Table 3 shows the results of analyzing the effects of the measured variables of the modified path model by classifying them into direct, indirect, and total effects. As for the effects of the variables on physical activity, social participation had a direct effect on physical activity, while social trust had an indirect effect. In terms of the impact on subjective health status, social participation and physical activity had a direct effect, whereas social trust and social participation had an indirect effect. Among the variables, the total effect of social participation was the highest, followed by that of physical activity and social trust. These variables accounted for 7.6% of participants' subjective health status.

Table 3 Standardized Estimates of the Path Model (N=4,578†) Click for larger image