Monitoring socioeconomic inequalities in sexually transmitted infections, tuberculosis, and violence: geocoding and choice of area-based socioeconomic measures--the public health disparities geocoding project (US).

OBJECTIVES To determine which area-based socioeconomic measures, at which level of geography, are suitable for monitoring socioeconomic inequalities in sexually transmitted infections (STIs), tuberculosis (TB), and violence in the United States. METHODS Cross-sectional analysis of public health surveillance data, geocoded and linked to area-based socioeconomic measures generated from 1990 census tract, block group, and ZIP Code data. We included all incident cases among residents of either Massachusetts (MA; 1990 population = 6016425) or Rhode Island (RI; 1990 population = 1003464) for: STIs (MA: 1994-1998, n = 26535 chlamydia, 7464 gonorrhea, 2619 syphilis; RI: 1994-1996, n = 4473 chlamydia, 1256 gonorrhea, 305 syphilis); TB (MA: 1993-1998, n = 1793; RI: 1985-1994, n = 576), and non-fatal weapons related injuries (MA: 1995-1997, n = 6628). RESULTS Analyses indicated that: (a). block group and tract socioeconomic measures performed similarly within and across both states, with results more variable for the ZIP Code level measures; (b). measures of economic deprivation consistently detected the steepest socioeconomic gradients, considered across all outcomes (incidence rate ratios on the order of 10 or higher for syphilis, gonorrhea, and non-fatal intentional weapons-related injuries, and 7 or higher for chlamydia and TB); and (c). results were similar for categories generated by quintiles and by a priori categorical cut-points. CONCLUSIONS Supplementing U.S. public health surveillance systems with census tract or block group area-based socioeconomic measures of economic deprivation could greatly enhance monitoring and analysis of social inequalities in health in the United States.