标题：Socioeconomic Gradients in Sexually Transmitted Diseases: A Geographic Information System–Based Analysis of Poverty, Race/Ethnicity, and Gonorrhea Rates in California, 2004–2006
摘要：Objectives. We quantified the relationship between gonorrheal infection rates in California and a measure of poverty status and investigated how this relationship and the spatial dispersion of cases varied among the 4 dominant racial/ethnic groups in the state. Methods. We geocoded gonorrhea cases reported in California between 2004 and 2006, and estimated the poverty status of each case by using the percentage of residents living below poverty in the census tract of residence. We calculated infection rates for African American, Asian, Hispanic, and White cases in each of 4 poverty strata. We mapped cases to visualize the patterns of spatial dispersion associated with each race/ethnicity–poverty combination. Results. There was a strong positive relationship between poverty and infection, but racial/ethnic disparities in infection, driven by a disproportionate level of gonorrhea among African Americans, eclipsed this differential. The degree of spatial aggregation varied substantially among groups and was especially pronounced for African Americans with gonorrhea in the highest poverty category. Conclusions. Prevention efforts should target low-income neighborhood “hot spots” to reach the largest numbers of cases, particularly among African Americans. Socioeconomic disparities in health make significant contributions to patterns of morbidity and mortality in the United States. 1 – 4 Socioeconomic status (SES) can directly affect access to health care and is often strongly correlated with behavioral patterns and community attributes that profoundly influence health risks and outcomes. Although the elimination of these inequalities is a fundamental objective of many public health initiatives, 5 quantifying and monitoring socioeconomic disparities in health is hampered by the paucity of socioeconomic data in most public health surveillance systems. The use of area-based socioeconomic measures offers a means to link case-based surveillance data with census-based information on associated populations and communities. 6 , 7 Case residential address data are assigned a latitude and longitude (geocoded), and these coordinates are then used to map geocoded cases and associate them with census tracts and the socioeconomic data collected within them as part of the decennial US Census. Thus, area-based socioeconomic measures provide estimates of the SES of individual geocoded cases, as well as direct measures of socioeconomic attributes of the communities in which they reside. 6 Sexually transmitted diseases (STDs) have long been of interest to public health practitioners concerned with socioeconomic disparities in health outcomes, 8 , 9 and they represent an ideal focus for geocoding-based studies of such variation. Relative to other infectious and chronic diseases, the geographic ubiquity and high incidence of STDs should allow socioeconomic disparities in infection rates to be readily quantified and accurately mapped. Analyses of data from Massachusetts, Rhode Island, and Virginia found significant positive relationships between rates of STDs and “percent below poverty,” a census-based measure of SES. 10 , 11 A number of other geocoding-based studies of socioeconomic variation in STDs produced similar findings, 12 – 14 but these were limited in their geographic breadth as they examined data from only large cities. Pronounced racial/ethnic heterogeneity in STDs has also been documented, 15 – 19 but because it is caused in part by disparities in SES among groups, the relative contributions of race/ethnicity and poverty to STD epidemiology remain unclear. Analyses that consider these relationships simultaneously across broader spatial scales, incorporating more cases with a collectively greater diversity of communities and racial/ethnic–socioeconomic combinations, are needed to more accurately and precisely quantify the influence of SES and race/ethnicity on patterns of STDs. We undertook a geocoding-based social gradient analysis by using gonorrhea incidence data collected over a 3-year period in California at a time when gonorrhea rates were increasing for the first time in decades. 20 The objectives of our study were (1) to quantify the relationship between infection rates and a measure of poverty status, (2) to assess whether and how this relationship varied among the 4 dominant racial/ethnic groups in the state, and (3) to examine variation in patterns of spatial dispersion of gonorrhea cases among racial/ethnic–poverty combinations by mapping geocoded cases, in order to better target gonorrhea prevention efforts.
