Evaluation of effect of social determinants and of impact of social programs on incidence, frequency of disability and treatment outcomes of leprosy

Leprosy continues to be a disease of public health importance in Brazil and many other low and middle income countries. Not much is known about the social epidemiology of leprosy nor the effectiveness of social policies on this poverty-related disease.

We propose a new way to investigate wich aspects of poverty increase the risk of leprosy, and how much Bolsa Familia ( a conditional cash transfer programme) introduced by the Brazilian government helped to decrease the risk of leprosy, reduced the risk of disability, and increased the proportion of cases of leprosy that completed treatment.

We are going to do this by using data already collected for administrative purposes. The main database is "Cadastro Único para Programas Sociais" (CadÚnico), used for screening applications for social programmes, which contains data on a range of socioeconomic indicators for 100 million people. We will link this to two databases: of benefits received, and to notification of leprosy. This will be done protecting the identification of individual data with strict security measures approved by the ethical committee. The unprecedented size of this cohort will allow the investigation of effects of social conditions (education, income, housing, family structure, ethnicity, water supply, sanitation) and of impact of interventions (income received, duration of support) on different aspects of leprosy in subpopulations defined by type of disease, age, geography, income, gender, housing, etc..

The project will produce evidence of the impact of social interventions and social deprivation on leprosy. The study will advance our understanding of leprosy and will strengthen the case for implementation of social interventions- in addition to biomedical interventions-to promote effective control of leprosy and pave the way for evaluation of impact on other poverty related diseases.

Leprosy remains a public health problem in Brazil. The epidemiology of leprosy is not fully understood: little is known about risk factors for infection, for disease, for delayed diagnosis and for treatment interruption. Large social inequalities and poverty are historical characteristics of Brazil; major improvements in the last 2 decades, with considerable expansion of programs in education, housing, social security and social development, make this an ideal setting for investigation.
We propose a novel strategy to investigate the effect of social determinants and the impact of the Brazilian cash-transfer program "Bolsa Familia" (BFP), on incidence, frequency of disabilities and treatment outcomes of leprosy by linking records from the database, "Cadastro Único para Programas Sociais" (CadÚnico), of applications for social programs, with detailed socio-economic information on over 100 million individuals, to two databases: individual payments of BFP, and the leprosy component of the National Notification Database, with information on notifications, disability, treatment and outcomes for all cases of leprosy. Statistical methods will include standard statistical methods for longitudinal data to estimate the effect of social determinants and regression discontinuity design and propensity scores to investigate the impact of BFP on notifications, disability, treatment and outcomes for all cases of leprosy.

The project will produce strong and specific evidence of the impact of social interventions and social deprivation on leprosy, advance our understanding of leprosy and will strengthen the case for implementation of social interventions- in addition to biomedical interventions- to promote effective leprosy control. There is a strong drive for structural social protection interventions for poverty related infectious diseases and evidence to support these policies can play an essential role in progress towards implementation.

The study will assess the effect of social and economic factors and the impact of the conditional transfer programme "Bolsa Familia" (BFP) on incidence, frequency of disabilities and treatment outcomes of leprosy in Brazil, overall and in sub populations. The study is based on routinely collected data. The Cadunico, the Brazilian database of applications for social programmes, containing detailed socio-economic information on over 100 million individuals, will be linked to the records of all individual payments of BFP, and the leprosy component of the National Notifiable Diseases Database (SINAN), with detailed information on all cases of leprosy. By producing specific and scientifically sound evidence of the effects of social deprivation and of the impact of social interventions on leprosy burden in Brazil, this study i) will advance our understanding of leprosy and ii) will strengthen the case for implementation of social interventions- in addition to, and in synergy with, biomedical interventions-, and provide information to support ( or adjust) policies aimed at socially vulnerable segments of the population, and their impact on effective leprosy control.

The institutions involved, LSHTM, Oswaldo Cruz Foundation (FIOCRUZ-Brasilia), Tropical Medicine Group of University of Brasilia (NMT/UNB) and Institute of Collective Health of Federal University of Bahia (ISC/UFBA), are recognized institutions in the field of public health research with international reputation for excellence. FIOCRUZ, UNB and ISC/UFBA signed a technical-scientific cooperation agreement with the Brazilian Ministry of Social Development (MSD), to develop a platform for impact evaluation of BFP and other social public policies on a wide spectrum of outcomes in health, education, work.

The well established collaboration between these institutions, LSHTM, and the Brazilian Ministries of Social Development and of Health, by periodic meetings and a continuous flow of communications, will maintain the steady interest of the policy makers on this research, and effectively contribute to the debate on type and extent of social interventions to be implemented in vulnerable communities in order to relieve the burden of leprosy.The multidisciplinary team is composed of researchers from LSHTM, UNB, FIOCRUZ, ISC/UFBA and UFF, including epidemiologists and statisticians with experience in epidemiology of infectious diseases and specifically leprosy, and design, management and interpretation of big data studies, and researchers experts in programming models and tools for high performance and data-intensive (big data) computing applied to Bioinformatics and Health. Post-doctoral researchers in epidemiology, statistics and information technology will be trained in the project. Other researchers, policy makers, directors of leprosy control programs and patients will benefit from the evidence produced.
Periodical meetings between UK and Brazilian researchers will be held, during which steps and achievements of the Project will be discussed and evaluated. Technical reports on state of progress of the Project and updated findings will be released each year ,and disseminated through governmental and non-governmental media.

This study will contribute to the advancement of the on going debate in the scientific community on the relationship between distributive social policies and infectious diseases of poverty around the world, with a specific focus on leprosy.
The results will be presented to the Brazilian National Leprosy Control Programme coordination and the coordination of MSD, with the aim of promoting a discussion at national level on the drive for integrating social programmes and leprosy control programmes, and to provide evidence for supporting/informing decision making related to social support and social programmes impact on leprosy, in order to ensure better life conditions and a better health for people vulnerable to or affected by leprosy.