摘要：Objectives. We examined the association between racial disparity in income and reported race-specific county-level bacterial sexually transmitted infections (STIs) in the United States focusing on disparities between Blacks and Whites. Methods. Data are from the US 2000 decennial census. We defined 2 race–income county groups (high and low race–income disparity) on the basis of the difference between Black and White median household incomes. We used 2 approaches to examine disparities in STI rates across the groups. In the first approach, we computed and compared race-specific STI rates for the groups. In the second approach, we used spatial regression analyses to control for potential confounders. Results. Consistent with the STI literature, chlamydia, gonorrhea, and syphilis rates for Blacks were substantially higher than were those for Whites. We also found that racial disparities in income were associated with racial disparities in chlamydia and gonorrhea rates and, to a lesser degree, syphilis rates. Conclusions. Racial disparities in household income may be a more important determinant of racial disparities in reported STI morbidity than are absolute levels of household income. Racial disparities in sexually transmitted infections (STIs) in the United States have been documented extensively. 1,2 In fact, racial disparities in STIs and HIV are ranked among the greatest racial disparities in health in the United States. 3 For example, in 2009 the rates of chlamydia and syphilis among Blacks in the United States were more than 8-fold the rates among Whites, and the disparity was even more pronounced for gonorrhea (20-fold). 1 Effective STI control and prevention efforts should include strategies to reduce racial disparities, 2 which was one of the major objectives of Healthy People 2010. 3 However, owing to the failure to meet the Healthy People 2010 goals, reducing or eliminating health disparity is one of the overarching goals of Healthy People 2020. 4 Thus, examining the factors that cause (or are associated with) racial disparities in STI rates can inform strategies to reduce or eliminate these disparities. When examining the aspects of social structure associated with endemically high rates of gonorrhea at the county level, Thomas and Gaffield 5 found a positive association between gonorrhea rates and income dualism (i.e., the average income differences between Black and White families) after controlling for other county-level demographic characteristics. Thomas and Gaffield suggest that if other studies confirm this association, efforts to reduce the substantial racial disparities in gonorrhea rates should include strategies to improve the existing income inequalities between Blacks and Whites as well. We examined the association between county-level racial disparity in income and reported bacterial STI rates. Our analysis adds to Thomas and Gaffield’s novel study 5 in 2 main ways. First, we investigated county-level racial disparity in income and 3 reportable STIs (total rates and specific rates for race and gender of chlamydia, gonorrhea, and primary and secondary syphilis) using more recent data (2000) on all the counties in the 48 contiguous states, whereas Thomas and Gaffield focused on county-level gonorrhea rates in 14 Southern states using data from 1986 to 1995. Second, we used spatial regression analyses to control for spatial dependence in reported STIs across counties; “spatial dependence” refers to the fact that STI rates in a given county are usually correlated with STI rates in bordering counties. Thus, our key contribution to the literature is to augment the work of Thomas and Gaffield by providing a comprehensive, updated analysis of county-level racial disparities in income and reported STIs (total rates and specific rates by race and gender). Studying the association of racial disparities in income with STI disparities by race can promote further examination of the mechanisms through which race–income disparities may be associated with or exacerbate disparities in STI rates between Blacks (or other racial minorities) and Whites in the United States. In addition, these studies may provide some insights into income distribution between racial groups as it relates to STI disparities and can inform decisions and strategies aimed at reducing or eliminating these disparities.
