Few of the social capital measures were significantly related to PHs once demographic and environmental variables, primary care resources, and ability to pay factors were controlled for. Under bonding social capital, shorter mean commute times for workers were associated with fewer adult PHs. An increase of 7 minutes in average commute time was associated with 4.1 additional nonelderly adult PHs and 22.8 additional elderly PHs. Shorter commute times for working adults could facilitate attending health care appointments, or assisting a family member or neighbor in attending theirs, as well as greater neighborhood participation for workers and more diverse interaction among all residents, facilitating the diffusion of information. Interestingly, the proportion of the population that was elderly was associated with fewer elderly PHs. More “elderly” communities may have more social support and community resources oriented to seniors’ particular needs (e.g., transportation assistance, senior activities, and housing).
Also under the bonding social capital category, less ethnic diversity was associated with fewer pediatric asthma hospitalizations. An increase of 30 percent in the probability of racial or ethnic interaction was associated with 4.2 additional pediatric asthma hospitalizations. It may be that intraethnic ties and interactions are particularly important for children, given the strong cultural and social influences and close contacts relied upon for child rearing.
Bridging social capital appeared to be important for nonelderly adults, as greater potential for interracial and interethnic interaction at the zip code-level was associated with fewer PHs. An increase of 30 percent in the probability of racial and ethnic interaction was associated with 5.6 fewer PHs among adults. It has been shown that “weak ties” (cross-cutting ties) are important for diffusion of information about employment opportunities among working-age adults (Granovetter 1973
); such ties may also facilitate diffusion of health care information.
Racial and ethnic segregation (relatively diversity) was also positively associated with the nonelderly adult PH rate and pediatric asthma rate in zip codes with higher percentages of black residents as well the nonelderly adult rate in zips with higher percentages of residents in poverty. This finding is corroborated by research that has found black–white segregation associated with deteriorated physical environments and economic opportunities, and fewer public resources in predominantly black areas (Massey and Denton 1989
; Williams 1999
), as well as higher black infant mortality rates, independent of income and poverty differences between blacks and whites (Polednak 1991
In contrast, racial and ethnic segregation (relatively diversity) was negatively associated with nonelderly adult PHs in zip codes with higher percentages of Latinos. This may seem counterintuitive, as did the finding that percent with LEP was negatively associated with PH rates among all three age groups. Having a concentration of immigrants speaking other languages could facilitate access for certain subgroups through shared communication networks and culturally competent providers (Angel and Angel 1992
; Komaromy et al. 1996
In terms of linking social capital, the multivariate analyses did not support the hypotheses. However, the positive relationship between faith-based congregations and PHs among nonelderly adults is not completely unexpected. Faith-based congregations are often the last to leave distressed, marginalized neighborhoods and the first to return (Foley et al. 2001
). The needs created by societal inequalities could overwhelm any “protective” effect of faith-based congregations. Indeed, some of faith-based congregations’ association with increased PHs in the nonelderly adult model was due to its interactions with the percentage of black residents (at higher percentages, this represented racial segregation) and percent poverty. Given the larger trends that affect these areas (e.g., capital flight, urban and rural deterioration) and shape the well-being of congregants and their communities (Foley et al. 2001
), our expectations for linking social capital, as exemplified by these institutions, may be unrealistic.
The finding that having a safety net clinic within 20 miles was related to lower adult PH rates confirms findings from a previous study in Virginia, where the availability of public ambulatory clinics was associated with lower PHs among low-income and elderly populations (Epstein 2001
). The positive relationship between the supply of general internists and adult PHs is not surprising, because internists are likely to take care of patients with the conditions studied and might be more likely to have offices in areas where more of these patients reside. Further, general internists and pediatricians tend to cluster more in urban areas than FPs/GPs and are thus less able to have a significant impact on PHs across all zip codes in the state (Parchman and Culler 1994
), like FPs/GPs appear to have had on pediatric asthma hospitalization rates in this study.
These analyses had a number of limitations. First, zip codes are at best a proxy for neighborhoods, although they do provide a way to examine variation across geographic areas in a more localized fashion than previously done in social capital and health studies. Second, many of the social capital measures were also only proxies for the different types of social capital identified in the conceptual framework. For example, to estimate the level of social capital associated with community organizations, one should know something about their level of activity or reach. Third, the design of the study (cross-sectional, ecological analyses) limits our ability to make causal inferences about how area social capital affects an individual's probability of having a PH. Fourth, as the data come from only one state, they have limited generalizability. Future research that attempts to replicate the findings of this study over time and across states would be valuable. Finally, although PHs have been validated as a community-level measure of poor access to care for nonelderly adults (Bindman et al. 1995
), it is still an indirect measure and may not correlate perfectly with actual access. Moreover, although timely primary care for chronic conditions is preferable to PHs, the latter could be preferable to not getting hospitalized when needed.