Background
There has been much research on the relationship between social capital and health. However, much of the research to date has been cross-sectional in nature and at the country level. Given that within a country population subgroups may experience social capital in ways that are different from that of the dominant group, this study focuses on the relationship between social capital and self-rated health (SRH) in a sample of urban, low-income mothers that are predominately racial and ethnic minorities. Moreover, we examine the relationship temporally, which is an advantage over cross-sectional social capital-SRH studies.
Originally framed at the societal level, social capital as defined by Putnam, refers to a combination of social organizations, social networks, and civic participation that can improve the efficiency of society by facilitating coordinated action [
1]. This definition characterizes social capital as a form of social cohesion generated at the societal level. It is also recognized that social capital can be generated at the individual level through one’s ability to access the benefits of social networks and structures [
2]. In public health, social capital is viewed as a multidimensional construct including individual and community level dimensions that acts as a determinant of health [
3,
4].
There is considerable evidence of a relationship between individual and community level social capital and good health, with trust, social participation, and reciprocity being the dimensions of social capital appearing to have the strongest relationship with health [
5‐
7]. At the individual level social capital involves not only the ability to access social networks and resources but assumes the ability to leverage and influence social relationships [
8]. Important in this conceptualization is the assumption of reciprocity between individual and community. In other words individuals both use and generate social capital. Snelgrove and colleagues frame individual perceptions of social capital as a collective benefit derived from generalized trust and community engagement rather than solely an individually experienced resource [
9]. Similarly, Poortinga found evidence of interactions between social capital at the national level and social trust and civic participation at the individual level, suggesting individual willingness to engage with others influences the relationship between community and individual levels of social capital [
10]. This has important ramifications for measurement. On it’s own social capital is not directly observable and there are limitations to aggregate measures of it; thus it’s presence is inferred from the measurement of observable antecedents such as trust and participation [
11‐
13]. In addition to these cognitive pathways between social capital and health, research suggests that household, neighborhood, and community characteristics contribute to the social capital-health relationship [
14].
The cross-sectional nature of many studies has made temporal ordering impossible; however, more recent literature suggests that certain dimensions of social capital at earlier time points are positively associated with self-rated health at later points in time. Examining changes in health status over time, Giordano and Lindström, found a significant association with inability to trust and deteriorating health status [
15]. They also found a similar association between generalized trust of others and better psychological health over time [
16]. Another study that used data from the British Household Panel Survey found that generalized trust and social participation at an earlier time point predicted self-rated health at a later time point, after adjusting for other health determinants [
17]. This temporal relationship between trust and social capital remained even after accounting for household context [
18]. Others have found a positive, temporal relationship between individual community service group membership and neighborhood trust and SRH over a two-year time period [
19]. In addition, Lamarca and colleagues found that higher levels of social capital were related to maintaining good health throughout pregnancy and the first six months post-partum [
20]. This research also revealed that individual social capital explained more variation in health than community level factors. Two recent meta-analyses of prospective studies of the relationship between social capital and mortality demonstrate a mixed relationship between social capital and health. Nyqvist and colleagues found strong evidence for an inverse association between social participation and mortality and they found that this relationship persists across male and female genders [
21]. They found weak evidence of a negative relationship between social networks and mortality. Choi and colleagues found little evidence of a relationship between seven dimensions of social capital and all-cause mortality, cardiovascular disease and cancer; however, they found a slight positive association between social and civic participation and mortality [
22]. A lack of consistent measures of social capital weakened their ability to detect associations.
A criticism of the social capital literature is the assumption that social capital is gender and power blind and there are calls to further study the relationship between social capital and health according to race/ethnicity, gender, and socioeconomic status [
7,
8,
11]. Particularly relevant to our work is the study of social capital among women, and in particular low-income women. Our study uses data from low-income, urban mothers participating in the Fragile Families and Child Wellbeing Study (FFCWB). This population is considered “fragile”, or vulnerable, because mothers who are not married to a child’s father at the time of that child’s birth have a greater risk of separating and living in poverty (for more on the economic hardships related to fragile families see Kalil & Ryan’s research) [
23].
Research indicates that social capital varies by gender and income. Generally speaking, women report both more use of and provision of support [
24]. This support, mainly conceptualized as social support, appears to protect health [
25,
26]. In low-income communities, social capital may act as a buffer against health disparities related to socioeconomic inequality, and may even promote social mobility [
27,
28]. At the same time, economic capital may be needed to generate and accumulate social capital for the benefit of health, thereby creating a dependency between the two [
28]. Similarly, persons who are unsure of their ability to reciprocate support may avoid accessing support [
29]. In a systematic review of 60 studies on the relationship between social capital and socioeconomic inequalities in health, Uphoff and colleagues, found evidence for both a buffer effect and a dependency effect of social capital on socioeconomic inequalities in health [
28]. However, among persons of very low socioeconomic status, there is some evidence that social capital has a stronger buffer effect on health. In recognition of numerous limitations of the studies reviewed (e.g. few testing for the interaction between SES and social capital, mostly cross-sectional studies), the study authors suggest further study of the role of social capital in health inequalities.
The current study addresses several of these gaps by using data from a longitudinal cohort study of primarily urban, low-income mothers who are racial and ethnic minorities. We sought to identify a temporal association between social capital at an earlier time (referred to as [t-1]) and health outcomes at a later time (denoted as [t]). We used measures that are similar to those that have been employed in other studies, including social support and trust, social participation, and neighborhood collective efficacy, thus adding to the construct validity of such measures. We aim to assess social capital in a population more likely to be living in poverty, thereby contributing to the discussion of health in underserved populations. In addition, the population surveyed in the FFCWB study consists of mostly racial and ethic minorities, who have experienced persistent health disparities [
30].
Discussion
Our aim was to assess the temporal relationship between social capital and SRH in a population of vulnerable women with children. Our results suggest that aspects of social capital, notably, social support and trust, as well as perceptions of neighborhood social control and cohesion predict future SRH. Our findings are consistent with previous research into social capital and SRH over time [
15‐
17,
19,
20]. Our findings differ from those that have found evidence of associations between social participation and mortality [
21,
22]. However, it is reasonable that different aspects of social capital may predict mortality as compared to SRH, which is a measure of one’s feelings of being well or unwell. While SRH has been shown to predict mortality, the cognitive and biological processes behind this relationship remain unclear [
35]. The findings also support previous research on social capital and health in underserved populations [
27‐
29]. Furthermore, the results underscore the well-established relationship among socioeconomic status, education, and health [
36‐
38]. Our findings reveal that trust and support seems to have components that are both individual in nature (e.g. having trusted others to help out with personal needs) and well as community-based (e.g. neighborly behaviors). This fits with previous research that has established a link between generalized social trust and SRH.
As others have discussed, social capital empowers citizens to participate in networks that also generate social capital [
11]. In other words, investment in social capital is compounding. As well, it appears that social capital at the individual level is driven by the contexts of known individuals in social networks, as opposed to the contexts of random individuals [
13]. Our findings support this given that the questions in the FFCWB interviews asked women about the behaviors of support and trust from persons known to the mother and the people comprising her immediate neighborhood.
These results point to the importance of the social environment as a health determinant. The findings suggest that social capital – SRH relationship in vulnerable populations is similar to that in the overall population. Such findings provide support for the idea that social capital provides a buffer effect [
28]. Additionally, these findings increase the empirical support for initiatives to increase social support and neighborhood investment, and other health-in-all-policies approaches. Policy solutions targeted at increasing certain aspects of social capital, for example policies that invest in social support structures, like affordable and accessible childcare or in the development of neighborhood associations, hold promise for improving health. Given that income was also positively related to SRH, policies that focus on reducing poverty and increasing access to education and employment should be similarly promising.
A strength of this study is that it is longitudinal, approximately 3,200 women across a four-year time frame. In addition, we investigate four separate components of the complex phenomena of social capital, along with multiple social, demographic, and behavioral health determinants on SRH, thereby reducing the potential for confounding. We assess both cognitive (e.g. trust, support, and social participation) and neighborhood-related aspects of social capital. We found evidence that suggests a temporal ordering between social capital and health, though this does not infer causation. That social capital was measured at an earlier time point, and we control for health at time (t-1), we control for reverse causation. Results of both the logistic regression model and the ordered logistic regression model provide robust analyses of these relationships.
At the same time, the study has some limitations. One is that we were limited to the questions asked by the Fragile Families survey. While the measures in this study are conceptually similar to measures used in the social capital literature, the construction of measures in this study is slightly different when compared to other studies of social capital and health. Given the complexity of social capital as well as the inherent limitations of measures that are highly dependent on self-perception, it is encouraging that similar findings have been reproduced across multiple measures of social capital. At the same time, measures utilized in this study do not allow a true comparison of social capital across populations. This should be a goal of future research. That these women were located in 20 urban areas around the Unites States, another goal for future research should be to investigate the effect of context (e.g. community and policy contexts) using multilevel modeling techniques.
Another limitation of this study is that health is a very complex variable and although multiple control variables were taken into account, there is always the chance that one was missed and ultimately could skew the results. An avenue for future research is to look at dose–response relationships between various social capital constructs and health. A further limitation comes from the fact that SRH is a subjective measure, based on a complex mix between one’s interpretation of health and contextual factors. SRH, however, is an inclusive and informative measure of health status, particularly in population studies [
35]. The FFCWB sample consists of low-income, urban mothers who are primarily racial and ethnic minorities, who were primarily unmarried to their partners at the time of childbirth and so findings may not extrapolate to other vulnerable populations. While our findings lend support to the idea that within this population the relationship between social capital and health is fairly similar to that in broader populations, given different measures throughout the literate more research is warranted. A final limitation is that the research offers a snapshot of how things changed over a single four-year period of time. It does not help explain how social capital changes over time or how such changes may affect health. More research is needed to explain the dynamics of social capital and its relationship with health over multiple time periods.
Conclusion
This research adds to the literature on the relationship between social capital and health over time. Many studies are cross-sectional in nature, while this study investigates the temporal relationship between the two. The findings in this study are consistent with others’ findings in that social support and trust, and perceptions and behaviors related to the neighborhood environment from an earlier time predict health at a later time. This is true even after accounting for various social, economic, health-related, and demographic variables, as well as prior health status. In conclusion, known social contexts, as measured by social support and trust, and social participation, as well as neighborhood are important. These findings provide support to policy initiatives designed to increase income equality and access to education, as well as to specific programs that support families and neighborhoods and suggest that they would be successful at improving health over time.
Competing interests
The authors declare that there are no competing interests.
Authors’ contributions
KND, NAW and JFS conceived and designed the study. NAW acquired and analyzed the data. KND and NAW interpreted the data. KND wrote the initial draft of the manuscript. KND, NAW and JFS revised the manuscript, read, and approved the final manuscript.