Effect of social capital on mental and physical health status: Accounting for reverse causation

Social epidemiologists argue that community social capital is an important resource which promotes population health by reducing mortality rates and the incidence of various chronic conditions. Measuring social capital as a community-level variable, however, ignores socioeconomic differences in access to social resources. This study conceptualizes social capital as an individual-level construct and explores whether it promotes physical or mental health status. Previous research has rarely considered the likelihood that social capital and health are endogenous. By contrast, this study accounts for the possibility that social capital and self-rated health are bidirectional and also examines whether perceived socioeconomic status augments or attenuates the health benefits associated with social capital. Two-stage least squares, with instrumental variables, is employed to correct for endogeneity bias. Data are drawn from the 1998 National Health Service Corps Community Health Assessment Survey. The analytic sample includes 6,395 individuals from eight counties in five states (Kansas, Colorado, Rhode Island, Pennsylvania, Connecticut). Findings show strong evidence that social capital and health are endogenous. While the effect of social capital on health is clearly positive, this relationship is mitigated for persons who feel “worse off than others in their community”. In other words, social capital is health advantageous, but the degree to which a person reaps health benefits from her social capital may in part be a function of where she perceives herself to be situated in the community's socioeconomic hierarchy.