Revise and Resubmit, Epidemiology and Infection.
Tuberculosis (TB) mortality rates in the U.S. fell rapidly from 1910-1933. However, during this period, racial disparities in TB mortality in the nation’s rapidly expanding cities grew. Because of long delays between infection and disease, TB mortality a poor indicator of short-term changes in transmission. We estimated the annual risk of TB infection (ARTI) in 11 large U.S. cities to understand whether rising inequality in mortality reflected in rising inequality in ARTI using city-level TB mortality data compiled by the U.S. Dept. of Commerce from 1910 to 1933. We estimated ARTI for blacks and whites using pediatric extrapulmonary TB mortality data among African-Americans and whites our panel of cities. We also estimated age-adjusted pulmonary TB mortality rates for these cities. We find that the ratio of ARTI for blacks vs. whites increased from 2.1 (95% CI=1.7, 2.5) in 1910 to 4.2 (95% CI=3.6, 5.1) in 1933. This change mirrored increasing inequality in age-adjusted pulmonary TB mortality during this period. Our findings suggest that rising racial inequality in ARTI likely reflects migration and increasing population density and segregation in Northern cities during this period.