The effect of conditional cash transfers on tuberculosis incidence and mortality is determined by ethnoracial and socioeconomic factors: a cohort study of 54 million individuals in Brazil.

Background: Conditional Cash Transfers (CCT) are the world's most widely implemented interventions for poverty alleviation. Still, there is no solid evidence of the CCT effects on the reduction of the burden of Tuberculosis (TB) in marginalized and extremely vulnerable populations. We estimated the effect of the (BFP), the largest CCT in the world, on TB incidence, mortality, and case-fatality rate using a nationwide cohort of 54.5 million individuals during a 12-year period in Brazil.

Methods: We selected low-income individuals who entered in the 100 Million Brazilians Cohort and were linked to nationwide TB registries between 2004 to 2015, and compared BFP beneficiaries and non-beneficiaries using a quasi-experimental impact evaluation design. We employed inverse probability of treatment weighting (IPTW) multivariable Poisson regressions, adjusted for all relevant socioeconomic, demographic, and healthcare confounding variables - at individual and municipal level. Subsequently, we evaluated BFP effects for different subpopulations according to ethnoracial factors, wealth levels, sex, and age. We also performed several sensitivity and triangulation analyses to verify the robustness of the estimates.

Findings: Exposure to BFP was associated with a large reduction in TB incidence in the low-income individuals under study (adjusted rate ratio [aRR]:0.59;95%CI:0.58-0.60) and mortality (aRR:0.69;95%CI:0.65-0.73). The strongest BFP effect was observed in Indigenous people both for TB incidence (aRR:0.37;95%CI:0.32-0.42), and mortality-aRR:0.35;95%CI:0.20-0.62), and in Black and Pardo people (Incidence-aRR:0.58;95%CI:0.57-0.59; Mortality -aRR:0.69;95%CI:0,64-0,73). BFP effects showed a clear gradient according to wealth levels and were considerably stronger among the extremely poor individuals for TB incidence (aRR:0.49, 95%CI:0.49-0.50) and mortality (aRR:0.60;95%CI:0.55-0.65). The BFP effects on case-fatality rates were also positive, however without statistical significance.

Interpretation: CCT can strongly reduce TB incidence and mortality in extremely poor, Indigenous, Black and Pardo populations, and could significantly contribute to achieving the End TB Strategy targets and the TB-related Sustainable Development Goals.