Socioeconomic determinants of leprosy new case detection in the 100 Million Brazilian Cohort: a population-based linkage study

Abstract

Summary Background Although leprosy is recognised as a disease of poverty, there is little evidence on the specific socioeconomic factors associated with disease risk. To inform targeted strategies for disease elimination, we investigated socioeconomic markers of leprosy risk in Brazil. Methods Socioeconomic data from the 100 Million Brazilian Cohort were linked to the Brazilian national disease registry (Sistema de Informação de Agravos de Notificação) for leprosy from Jan 1, 2007, to Dec 31, 2014. Using Poisson regression, we assessed the association of socioeconomic factors with risk of incident leprosy in the full cohort and in children (aged 0–15 years), by leprosy subtype and region of residence. Findings In an analysis of 23 899 942 individuals including 18 518 patients with leprosy, increased levels of deprivation were associated with an increased risk of leprosy in Brazil. Directions of effect were consistent in children younger than 15 years and across disease subtypes. Individuals residing in regions with the highest poverty in the country (central-west, north, and northeast regions) had a risk of leprosy incidence five-to-eight times greater than did other individuals. Decreased levels of income and education and factors reflecting unfavourable living conditions were associated with an up to two-times increase in leprosy incidence (incidence rate ratio 1·46, 95% CI 1·32–1·62, for lowest vs highest quartile of income per capita; 2·09, 95% CI 1·62–2·72, for lowest vs highest level of education). Interpretation Within the poorest half of the Brazilian population, the most deprived individuals have the greatest risk of leprosy. Strategies focusing on early detection and treatment in the poorest populations could contribute substantially to global disease control. Funding Medical Research Council, Wellcome Trust, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brazil), the Conselho Nacional das Fundações Estaduais de Amparo à Pesquisa, Economic and Social Research Council, Biotechnology and Biological Sciences Research Council, Conselho Nacional de Desenvolvimento Científico e Tecnológico, and Fundação de Apoio à Pesquisa do Distrito Federal.

Incidence of and Factors Associated With Leprosy Among Household Contacts of Patients With Leprosy in Brazil

“…In conducting a nationwide analysis of 42 725 household contacts of leprosy cases from the 100 Million Brazilian Cohort, this investigation provided robust estimates of the incidence of leprosy among household contacts. Among these contacts, leprosy incidence was estimated to be approximately 37times higher than that in the 100 Million Brazilian Cohort overall (17.1 per 100 000 person-years) 8 and 50-times higher than the rate recorded for the general population of Brazil in 2017 (12.9 per 100 000 person-years). 18 Furthermore, although household contacts younger than 15 years had a lower detection rate of leprosy than adults, the rate was 100 times higher than in the full population of children from the 100 Million Brazilian Cohort (5.2 per 100 000 person-years).…”

“…In this study, leprosy risk among household contacts was similar across geographic location or socioeconomic conditions of households, which differed from previous studies. 8,25,26 However, given that the households affected by leprosy in the 100 Million Brazilian Cohort were more likely to have low-income circumstances, 8 the sample in the present study was relatively homogeneously composed of individuals of limited resources, which may have limited our ability to differentiate any health outcomes associated with socioeconomic status. 27 The high proportion of cases associated with exposure to leprosy cases within the household compared with exposure outside of household suggests that household contacts with low-income status may benefit from targeted and effective strategies to prevent transmission, such as strengthening screening of contacts.…”

“…16,17 We estimated the Levin population attributable risk of being exposed to a leprosy case within the household using previous leprosy incidence estimates from the 100 Million Brazilian Cohort as a proxy for the unexposed population. 8 We estimated the crude and adjusted odds ratio (OR) of developing a subsequent leprosy case by the clinical features of the primary case and the socioeconomic and demographic characteristics of the household contact using multilevel mixed-effects logistic regressions allowing for state-and household-specific random effects. Adjusted models were built using a backward selection approach, where we first included all variables with P < .20 in the univariate analysis and removed variables one by one, maintaining those with P < .05 in the final model.…”

Prevalence of Mycobacterium leprae in armadillos in Brazil: A systematic review and meta-analysis

“…Brazil is a high-burden country for Hansen's Disease [11], with incidence varying according to geographic and socioeconomic determinants [12]. Although the disabling and disfiguring sequelae of Hansen's Disease are entirely avoidable if diagnosed and treated early [13], the social stigma of 'leprosy' has not been entirely dispelled, and still has a profoundly negative impact on people diagnosed with this disease [14,15].…”

Physical Disabilities Caused by Leprosy in 100 Million Cohort in Brazil

“…Although there have been large-scale studies in Brazil studying the social determinants of leprosy incidence and treatment default [8,9], risk factors for leprosy-associated disability at the time of diagnosis remain scarcely investigated. In Brazil, there are problems related to underdiagnosis and underreporting of new cases of leprosy, which hashave a major impact on the ability to plan control control activities for the disease.…”