Objective: To evaluate tuberculosis (TB) risk in three different US locations--Chicago, Illinois; Fulton County, Georgia; and the state of South Carolina--using two census-based measures of neighborhood-level deprivation and a geographic information system.
Method: Individual-level data, including race and ZIP code of residence, were obtained for the three sites. TB cases were geocoded at the ZIP code tabulation area (ZCTA) level. Socio-economic status (SES) was defined at the ZCTA level using two Census 2000-based measures of socio-economic disadvantage: 1) percentage of population below poverty and 2) Townsend Deprivation Index. Based separately on the distributions of poverty and Townsend social deprivation scores, ZCTAs in each site were grouped into quartiles reflecting relative socio-economic well-being. To evaluate TB incidence in low- vs. high-SES neighborhoods, average annual TB incidence rates were calculated for the highest and lowest ZCTA quartiles.
Results: In all sites, TB incidence rates were significantly higher in high poverty/high social deprivation ZCTAs (P < 0.0001).
Conclusions: Both census-based indicators performed well in distinguishing areas with high TB incidence rates from areas with little or no TB. Due to simplicity, the single poverty measure rather than the multifactorial Townsend index might be especially useful in identifying high-risk neighborhoods for targeted TB prevention efforts.