Social capital and perceived health in Japan: An ecological and multilevel analysis

Abstract

Numerous empirical studies, largely conducted in Western societies, have linked social capital to health outcomes. However, few studies thus far have been conducted in northeastern Asian countries, particularly Japan. Therefore, whether social capital is a determinant of health in Japanese society remains unclear. This study attempted to provide new evidence for the impact of social capital on health in Japan by analyzing original survey data with two different statistical models. In total, 1910 subjects were randomly selected from 210 enumeration districts (EDs) considered in the 2000 population census. In the present study, after excluding missing data on the outcome and predictor variables, we conducted an analysis of 1157 individuals nested within 206 EDs. Ecological and multilevel regression analyses were performed to examine the association between social capital and health, measured by the General Health (GH) perception item (a subcategory of Short Form 36 (SF-36)), and to estimate the impact of aggregated indicators of social capital on health. We developed an original Japanese version of three social capital items (perceived helpfulness, kindness, and greeting) based on previous studies and expert opinions and prepared a social cohesion index that integrated these three social capital items. The ecological model, after adjusting for sociodemographic factors, revealed that perceived helpfulness and greeting, along with the social cohesion index, were observed to have statistically significant associations with GH. The multilevel model, after adjusting for individual social capital perceptions, indicated that the two aggregated indicators of community social capital (kindness and greeting), along with the social cohesion index, showed a statistically significant association with GH. These results showed the existence of a contextual effect of social capital on health outcomes, although individual differences in social capital perceptions in Japan were considered.

Introduction

The association between social capital and health has been examined in nearly a dozen industrial and developing countries in North America, Western and Eastern Europe, and Australia (De Silva et al., 2006, Islam et al., 2006, Kawachi et al., 2004, Macinko and Starfield, 2001). However, few studies have been conducted in northeastern Asian countries thus far; in particular, studies in Japan have remained sparse. It is unclear whether the concept of social capital, which has been primarily developed in Western contexts, can be applied to the Asian context.

Social capital, a concept that originated in early 20th century social science (Putnam, 2000, Putnam, 2002), has been defined as broadly as “those tangible substances count for most in the daily lives of people” (Hanifan, 1916, p. 130). Later academics, such as Jane Jacobs (1961) and Glenn C. Loury (1977), used the term social capital to describe specific social phenomena tin their analyses, but it was not until the 1980s that the term was fully developed by two renowned sociologists: James S. Coleman and Pierre Bourdieu. Coleman adapted the rational choice theory and, based on methodological individualism, employed “social capital” as the missing link necessary to analyze complex social phenomena at the macro level (Coleman, 1988, Coleman, 1990). Bourdieu analyzed the concept of “capital” in several aspects and employed the concept of social capital to refine his theory of hierarchal social structure (Bourdieu, 1980, Bourdieu, 1986).

Although these academics and theorists crystallized the concept of social capital, political scientist R. Putnam popularized it and prompted debates about the concept. His idea of social capital was developed based on approximately 20 years of study in Italy, and he adapted his understanding of social capital to analyze American society. The core of his social capital concept was that social capital is a characteristic of social networks, though he defined social capital in several ways, such as “features of social organization, such as trust, norms, and networks, that can improve the efficiency of society by facilitating coordinated actions” (Putnam, 1993, p. 167) and “connections among individuals - social networks and the norms of reciprocity and trustworthiness that arise from them” (Putnam, 2000, p. 19).

With respect to health-related fields, the theory of social capital has been characterized by an imbalance of perspectives rather than a lack of consensus (Moore, Shiell, Hawe, & Haines, 2004). However, other researchers have suggested that there are in fact two theories of social capital in public health research, a theory of social cohesion and a theory of social networks, but that these two theories are not mutually exclusive (Kawachi, 2006). In other words, social capital can be divided into two dimensions:structural social capital and cognitive social capital. Structural social capital refers to what people do (e.g., associational links, networks), which can be objectively verified, and cognitive social capital refers to what people feel (e.g., social cohesion, trust), which can be subjectively verified (Harpham, 2008). Some studies have demonstrated that these two dimensions may have different effects on health outcomes (De Silva, McKenzie, Harpham, & Huttly, 2006).

The term “social cohesion” was coined and developed by Richard G. Wilkinson to explain the relationship between income inequality and population health (Wilkinson, 1996). In fact, he used this concept interchangeably with social capital and has not clearly shown the difference between these two concepts. However, as Kawachi pointed out, the concept of social cohesion bears similarities to the concept of social capital, but the notion of social capital includes an aspect of “community cohesiveness,” i.e., the social context in which people lead their lives (Kawachi & Kennedy, 1997). Kawachi therefore implied that social cohesion is an attribute of social capital (Kawachi, 2006). Thus, in the present study, we conceptualize social cohesion as an aspect of each of the two dimensions of social capital: the cohesive and cognitive dimensions.

Meanwhile, the literature has not yet clearly indicated whether social capital has any impact on health in Japanese society. At the individual and ecological levels, some evidence has been presented for associations among cognitive social capital, participation, and self-rated health in the Japanese population (Fujisawa et al., 2007, Fujisawa et al., 2004). Moreover, other studies conducted in certain parts of Japan, such as the Aichi region, showed associations between the social capital index and health in a specific age group (Ichida, Yoshikawa, Hirai, Kondo, & Kobayashi, 2005). Although these studies indicated certain implications for the importance of the association between social capital and health in some contexts, it remains unclear whether social capital, particularly community-based social capital, is a determinant of health in Japanese society and whether Western-derived measures of social capital can be applied to Japanese culture.

To the best of our knowledge, no previous study has clearly reported on the impact of cognitive social capital, especially of the cohesive dimension, on health outcomes at the community level for Japan as a whole, although evidence of the impact of cognitive social capital on health outcomes in specific areas and age groups has been shown (Ichida, 2007). For these reasons, in the present study, we used a multilevel perspective to explore new evidence pertaining to whether cognitive social capital at the community level is a determinant of health in the whole of Japanese society.