Social determinants of tuberculosis case rates in the United States

Background: Social capital has been related to a number of important public health variables such as overall mortality, health status, and sexually transmitted infections (including AIDS case rates). However, the relationship of social capital to tuberculosis has received little attention. Because social capital may be related to the constructs of poverty and income inequality, any exploration of the correlation between social capital and tuberculosis should include examination of the interrelationships with poverty and income inequality as well. Objective: This study examined the state-level relationship between social capital, poverty, income inequality, and tuberculosis case rates. Methods: The design was state-level, correlational analysis (including bivariate linear correlational analysis, and multivariate linear stepwise regression analysis). Main outcome measures were 1999 state-level case rates of tuberculosis. Results: In bivariate analyses, poverty, income inequality, and social capital were all significantly correlated with tuberculosis case rates. In stepwise multiple regression analyses predicting tuberculosis case rates from this set of three predictor variables, social capital and income inequality entered the regression equation (with social capital being the strongest predictor variable). Conclusions: These results suggest that social capital is highly predictive of tuberculosis at the state level. The results indicate the need for further research into this potentially causal relationship, including the examination of structural interventions designed to increase social capital.