The results of an innovative study to understand what factors may influence who contracts tuberculosis (TB)/HIV co-infection in San Diego show a significant shift in the ethnic makeup of the disease, with the majority of cases now coming from the Hispanic community.
The results of this paper, "HIV and Tuberculosis Co-infection Among Hispanics in Southern California: An Increasing Health Disparity," will appear in the February edition of the American Journal of Public Health.
"While the overall numbers are modest, our study shows that what used to be mostly a disease of white and black patients in San Diego is now largely a disease of Hispanics," said Timothy Rodwell MD, PhD, MPH, associate physician/fellow in the Division of Global Public Health at UC San Diego. "This indicates that the benefits of prevention and treatment of TB and HIV over the last decade have been uneven in the different ethnic/racial groups in this region."
HIV is a potent risk factor for TB disease. It increases the risk of latent TB infection reactivation, the rate of disease progression and the risk of new infections. TB also accelerates HIV disease progression, increasing infectivity and reducing HIV treatment efficacy.
"The synergy of TB and HIV has created a worldwide public health crisis and has significantly complicated attempts to eliminate TB in both the industrialized and developing worlds," noted Rodwell.
Rodwell's team analyzed San Diego County TB surveillance data from 1993 through 2007, grouping cases by HIV status: positive, negative or unknown. Of the 5,172 TB cases analyzed, 8.8 percent were also infected with HIV. The number of new co-infected cases did not change significantly during this period, but the proportion of cases among Hispanics did increase significantly, while the proportion of cases among non-Hispanic white and black patients decreased.
Hispanics now account for more than 80 percent of all TB-HIV co-infection cases in the county, further widening existing health disparities in this region. Co-infected patients are significantly more likely to be Hispanic 30 to 49 year-old male injection drug users than any other patient group. Researchers recommend that since the burden of TB and HIV in San Diego has shifted to Hispanics, the disparity must be addressed with focused binational TB and HIV prevention efforts.
Rodwell explained, "With more than 40,000 people crossing the border between Mexico and San Diego on a daily basis, and our finding that the majority of new TB-HIV co-infection cases occurred among Hispanics that were born in Mexico, it is clear that future interventions to address this health disparity will need to be binational in nature."
Study authors include Timothy C. Rodwell, Richard F.W. Barnes, Steffanie A. Strathdee, and Richard S. Garfein are with the Department of Medicine, University of California, San Diego. Marisa Moore is with the Centers for Disease Control and Prevention, stationed at the Tuberculosis Control and Refugee Health Program in the San Diego County Health and Human Services Agency, California and Kathleen S. Moser is the director of the Tuberculosis Control and Refugee Health Program in the San Diego County Health and Human Services Agency, California. Annie Raich was with the School of Public Health, San Diego State University, California at the time of the study.
This study was supported by the California HIV/AIDS Research Program at the University of California and the National Institutes of Health.