Conditional Cash Transfer Program and Leprosy Incidence: Analysis of 12.9 Million Families From the 100 Million Brazilian Cohort.

Leprosy is a neglected tropical disease predominately affecting poor and marginalized populations. To test the hypothesis that poverty-alleviating policies might be associated with reduced leprosy incidence, we evaluated the association between the Brazilian Bolsa Familia (BFP) conditional cash transfer program and new leprosy case detection using linked records from 12,949,730 families in the 100 Million Brazilian Cohort (2007-2014). After propensity score matching BFP beneficiary to nonbeneficiary families, we used Mantel-Haenszel tests and Poisson regressions to estimate incidence rate ratios for new leprosy case detection and secondary endpoints related to operational classification and leprosy-associated disabilities at diagnosis. Overall, cumulative leprosy incidence was 17.4/100,000 person-years at risk (95% CI: 17.1, 17.7) and markedly higher in "priority" (high-burden) versus "nonpriority" (low-burden) municipalities (22.8/100,000 person-years at risk, 95% confidence interval (CI): 22.2, 23.3, compared with 14.3/100,000 person-years at risk, 95% CI: 14.0, 14.7). After matching, BFP participation was not associated with leprosy incidence overall (incidence rate ratio (IRR)Poisson = 0.97, 95% CI: 0.90, 1.04) but was associated with lower leprosy incidence when restricted to families living in high-burden municipalities (IRRPoisson = 0.86, 95% CI: 0.77, 0.96). In high-burden municipalities, the association was particularly pronounced for paucibacillary cases (IRRPoisson = 0.82, 95% CI: 0.68, 0.98) and cases with leprosy-associated disabilities (IRRPoisson = 0.79, 95% CI: 0.65, 0.97). These findings provide policy-relevant evidence that social policies might contribute to ongoing leprosy control efforts in high-burden communities.

Effects of maternal geohelminth infections on allergy in early childhood.

BACKGROUND: Maternal geohelminth infections during pregnancy may protect against allergy development in childhood. OBJECTIVE: We sought to investigate the effect of maternal geohelminths on the development of eczema, wheeze, and atopy during the first 3 years of life. METHODS: A cohort of 2404 neonates was followed to 3 years of age in a rural district in coastal Ecuador. Data on wheeze and eczema were collected by means of questionnaire and physical examination at 13, 24, and 36 months of age. Atopy was measured based on skin prick test (SPT) reactivity to 9 allergens at 36 months. Maternal stool samples were examined for geohelminths by microscopy. Data on potential confounders was collected after birth by questionnaire. RESULTS: Geohelminths were observed in 45.9% of mothers. Eczema and wheeze were reported for 17.7% and 25.9%, respectively, of 2069 (86.1%) children with complete follow-up to 3 years, and allergen SPT reactivity to any allergen was present in 17.2% and to house dust mite in 8.7%. Maternal geohelminth infections were not significantly associated with eczema (adjusted odds ratio [OR], 1.26; 95% CI, 0.98-1.61), wheeze (adjusted OR, 1.02; 95% CI, 0.82-1.27), and SPT reactivity to any allergen (adjusted OR, 0.79; 95% CI, 0.61-1.01). In subgroup analyses maternal geohelminths were associated with a significantly reduced risk of SPT reactivity to mite and other perennial allergens, and maternal ascariasis was associated with an increased risk of eczema and reduced risk of SPT reactivity to all allergens. CONCLUSION: Our data do not support a protective effect of maternal infections with geohelminth parasites during pregnancy against the development of eczema and wheeze in early childhood, although there was evidence in subgroup analyses for a reduction in SPT reactivity to house dust mites and perennial allergens.

A genome-wide association study of asthma symptoms in Latin American children.

BACKGROUND: Asthma is a chronic disease of the airways and, despite the advances in the knowledge of associated genetic regions in recent years, their mechanisms have yet to be explored. Several genome-wide association studies have been carried out in recent years, but none of these have involved Latin American populations with a high level of miscegenation, as is seen in the Brazilian population. METHODS: 1246 children were recruited from a longitudinal cohort study in Salvador, Brazil. Asthma symptoms were identified in accordance with an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Following quality control, 1,877,526 autosomal SNPs were tested for association with childhood asthma symptoms by logistic regression using an additive genetic model. We complemented the analysis with an estimate of the phenotypic variance explained by common genetic variants. Replications were investigated in independent Mexican and US Latino samples. RESULTS: Two chromosomal regions reached genome-wide significance level for childhood asthma symptoms: the 14q11 region flanking the DAD1 and OXA1L genes (rs1999071, MAF 0.32, OR 1.78, 95% CI 1.45-2.18, p-value 2.83 × 10(-8)) and 15q22 region flanking the FOXB1 gene (rs10519031, MAF 0.04, OR 3.0, 95% CI 2.02-4.49, p-value 6.68 × 10(-8) and rs8029377, MAF 0.03, OR 2.49, 95% CI 1.76-3.53, p-value 2.45 × 10(-7)). eQTL analysis suggests that rs1999071 regulates the expression of OXA1L gene. However, the original findings were not replicated in the Mexican or US Latino samples. CONCLUSIONS: We conclude that the 14q11 and 15q22 regions may be associated with asthma symptoms in childhood.

Risk factors for non-atopic asthma/wheeze in children and adolescents: a systematic review.

BACKGROUND: The study of non-atopic asthma/wheeze in children separately from atopic asthma is relatively recent. Studies have focused on single risk factors and had inconsistent findings. OBJECTIVE: To review evidence on factors associated with non-atopic asthma/wheeze in children and adolescents. METHODS: A review of studies of risk factors for non-atopic asthma/wheeze which had a non-asthmatic comparison group, and assessed atopy by skin-prick test or allergen-specific IgE. RESULTS: Studies of non-atopic asthma/wheeze used a wide diversity of definitions of asthma/wheeze, comparison groups and methods to assess atopy. Among 30 risk factors evaluated in the 43 studies only 3 (family history of asthma/rhinitis/eczema, dampness/mold in the household, and lower respiratory tract infections in childhood) showed consistent associations with non-atopic asthma/wheeze. No or limited period of breastfeeding was less consistently associated with non-atopic asthma/wheeze. The few studies examining the effects of overweight/obesity and psychological/social factors showed consistent associations. We used a novel graphical presentation of different risk factors for non-atopic asthma/wheeze, allowing a more complete perception of the complex pattern of effects. CONCLUSIONS: More research using standardized methodology is needed on the causes of non-atopic asthma.

Genetic polymorphism (rs6587666) in FLG protects from eczema in admixed Brazilian children population with high African ancestry.

Genetic variants in filaggrin (FLG) are key in eczema and are less common in Africans than in Europeans and Asians. Here we examined the association between FLG Single Nucleotide Polymorphisms (SNPs) and eczema in a population of admixed Brazilian children and whether African ancestry modifies this association. We included 1010 controls and 137 cases and ran logistic regressions between SNPs in FLG and eczema in the studied population and also stratified the analyses according to the degree of African ancestry. In addition, we tested the replication of the findings on an independent set of individuals, as well as, we verified the impact on FLG expression according to each SNP genotype. The T allele of SNP rs6587666 was negatively associated with eczema in additive model (OR: 0.66, 95% CI: 0.47-0.93, P: 0.017). Moreover, African ancestry modifies the association between rs6587666 and eczema. The effect of the T allele was higher among individuals with higher African ancestry and the association with eczema was lost in individuals with lower African ancestry. In our analyses the expression of FLG in skin was slightly downregulated by the presence of the T allele of rs6587666. In our population, the T allele of rs6587666 in FLG was associated with protection to eczema and the degree of African ancestry was able to modify the observed association.

Poverty, dirt, infections and non-atopic wheezing in children from a Brazilian urban center.

BACKGROUND: The causation of asthma is poorly understood. Risk factors for atopic and non-atopic asthma may be different. This study aimed to analyze the associations between markers of poverty, dirt and infections and wheezing in atopic and non-atopic children. METHODS: 1445 children were recruited from a population-based cohort in Salvador, Brazil. Wheezing was assessed using the ISAAC questionnaire and atopy defined as allergen-specific IgE ≥ 0.70 kU/L. Relevant social factors, environmental exposures and serological markers for childhood infections were investigated as risk factors using multivariate multinomial logistic regression. RESULTS: Common risk factors for wheezing in atopic and non-atopic children, respectively, were parental asthma and respiratory infection in early childhood. No other factor was associated with wheezing in atopic children. Factors associated with wheezing in non-atopics were low maternal educational level (OR 1.49, 95% CI 0.98-2.38), low frequency of room cleaning (OR 2.49, 95% CI 1.27-4.90), presence of rodents in the house (OR 1.48, 95% CI 1.06-2.09), and day care attendance (OR 1.52, 95% CI 1.01-2.29). CONCLUSIONS: Non-atopic wheezing was associated with risk factors indicative of poverty, dirt and infections. Further research is required to more precisely define the mediating exposures and the mechanisms by which they may cause non-atopic wheeze.

Validation of epidemiological tools for eczema diagnosis in Brazilian children: the ISAAC's and UK Working Party's criteria.

BACKGROUND: Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children. METHODS: We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema. RESULTS: Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting. CONCLUSIONS: Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.

Understanding the dynamics of asthma symptoms between childhood and adolescence using latent transition analysis.

OBJECTIVES: Asthma patterns in childhood are important predictors of unwanted outcomes in adolescence. We aimed to define asthma phenotypes in childhood and adolescence and evaluate the transitions between these phenotypes and factors potentially associated with the transitions. METHODS: Baseline (1445 children), first round (1363 children/early adolescents) and second round (1206 adolescents) data from the SCAALA Project in Salvador, Brazil, were used. Phenotypes were defined by latent class analysis at three time points. Transitions between phenotypes were described and the effects of factors associated with transition probabilities estimated using latent transition analysis. RESULTS: The "asymptomatic" and "symptomatic" phenotypes were identified. Approximately 5-6% of asymptomatic children in childhood/later childhood and early adolescence became symptomatic later in time. Maternal common mental disorders were identified as important risk factor for unhealthy states. CONCLUSIONS: Asthma manifestations are characterized by frequent movements, especially between childhood and adolescence. Our study, by simultaneously defining disease subtypes, and examining the transitions and their potential predictors, highlights the importance of longitudinal studies to advance the understanding of the effects of social, environmental and biological mechanisms underlying asthma trajectories over time.

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

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.

Genetic variants in 17q12-21 locus and childhood asthma in Brazil: Interaction with Varicella zoster virus seropositivity.

BACKGROUND: Asthma is a complex disease with worldwide public health relevance, is related to environmental causes and a genetic predisposition. The chromosomal 17q12-21 locus has been consistently demonstrated to be associated with asthma risk. The effects of variants in the 17q12-21 locus on childhood asthma were first identified in a genome wide- association study. Since that time, those findings have been replicated in different populations but not in South American populations. OBJECTIVE: This study aimed to investigate the role of variants in the 17q12-21 locus on asthma in a sample of Brazilian children. METHODS: This was a cross-sectional study conducted on a cohort of 1247 children. These analyses used 50 Single Nucleotide Variants (SNVs) in the 17q12-21 locus were genotyped as part of a genome wide association study (GWAS). RESULTS: Four SNVs (rs4065275, rs12603332, rs73985228 and rs77777702) were associated with childhood asthma. The rs73985228 exhibited the strongest association across the different genetic models (OR, 95%CI 2.8, 1.44-3.21, p < 0.01). In an analysis that was stratified by atopy, two SNVs (rs73985228 and rs2715555) were found to be associated with atopic and non-atopic asthma. For the first time, we observed a significant interaction with seropositivity for the Varicella zoster virus (for rs4065275, p = 0.02, and for rs12603332, p = 0.04); i.e., the association was found in those who were seropositive but not in those who were seronegative for this virus. CONCLUSIONS: We confirmed the associations of variants in the 17q12-21 locus with atopic and non-atopic asthma and identified an interaction with seropositivity for the Varicella zoster virus.

Effect of city-wide sanitation programme on reduction in rate of childhood diarrhoea in northeast Brazil: assessment by two cohort studies.

BACKGROUND: A city-wide sanitation intervention was started in Salvador, Brazil, in 1997 to improve sewerage coverage from 26% of households to 80%. Our aim was to investigate the epidemiological effect of this city-wide sanitation programme on diarrhoea morbidity in children less than 3 years of age. METHODS: The investigation was composed of two longitudinal studies done in 1997-98 before the intervention (the sanitation programme) and in 2003-04 after the intervention had been completed. Each study consisted of a cohort of children (841 in the preintervention study and 1007 in the postintervention study; age 0-36 months at baseline) who were followed up for a maximum of 8 months. Children were sampled from 24 sentinel areas that were randomly chosen to represent the range of environmental conditions in the study site. At the start of each study an individual or household questionnaire was applied by trained fieldworkers; an environmental survey was done in each area before and after introduction of the sanitation programme to assess basic neighbourhood and household sanitation conditions. Daily diarrhoea data were obtained during home visits twice per week. The effect of the intervention was estimated by a hierarchical modelling approach fitting a sequence of multivariate regression models. FINDINGS: Diarrhoea prevalence fell by 21% (95% CI 18-25%)-from 9.2 (9.0-9.5) days per child-year before the intervention to 7.3 (7.0-7.5) days per child-year afterwards. After adjustment for baseline sewerage coverage and potential confounding variables, we estimated an overall prevalence reduction of 22% (19-26%). INTERPRETATION: Our results show that urban sanitation is a highly effective health measure that can no longer be ignored, and they provide a timely support for the launch of 2008 as the International Year of Sanitation.

Determinants of cognitive function in childhood: a cohort study in a middle income context.

BACKGROUND: There is evidence that poverty, health and nutrition affect children's cognitive development. This study aimed to examine the relative contributions of both proximal and distal risk factors on child cognitive development, by breaking down the possible causal pathways through which poverty affects cognition. METHODS: This cohort study collected data on family socioeconomic status, household and neighbourhood environmental conditions, child health and nutritional status, psychosocial stimulation and nursery school attendance. The effect of these on Wechsler Pre-School and Primary Scale of Intelligence scores at five years of age was investigated using a multivariable hierarchical analysis, guided by the proposed conceptual framework. RESULTS: Unfavourable socioeconomic conditions, poorly educated mother, absent father, poor sanitary conditions at home and in the neighbourhood and low birth weight were negatively associated with cognitive performance at five years of age, while strong positive associations were found with high levels of domestic stimulation and nursery school attendance. CONCLUSION: Children's cognitive development in urban contexts in developing countries could be substantially increased by interventions promoting early psychosocial stimulation and preschool experience, together with efforts to prevent low birth weight and promote adequate nutritional status.

Giardia duodenalis infection and anthropometric status in preschoolers in Salvador, Bahia State, Brazil.

The aim of this study was to estimate the association between Giardia duodenalis infection and anthropometric deficits, as measured by weight-for-age and height-for-age. This cross-sectional study included 629 children from 12 to 48 months of age, selected from 30 geographic areas in the city of Salvador, Bahia State, Brazil. Poisson regression and linear regression were used for the multivariate statistical analyses. G. duodenalis was diagnosed in 13.5% of the children. The children's breastfeeding duration and living conditions (garbage collection and paved streets or sidewalks) modified the effect of G. duodenalis infection on anthropometric status. Among infected children, there were statistically significant associations between weight deficit and shorter breastfeeding (PR=2.22; 95%CI: 1.56-3.14) and inadequate paving of streets and sidewalks (PR=2.00; 95%CI: 1.37-2.92), while height deficit was associated with deficient public garbage collection (PR=2.21; 95%CI: 1.31-2.51). In the linear regression, the association with the anthropometric indicators remained positive and statistically significant. The child's unhealthy living environment aggravated the negative effect of G. duodenalis infection on anthropometric status, and breastfeeding was a protective factor in the outcome.

Socioeconomic risk markers of leprosy in high-burden countries: A systematic review and meta-analysis.

Over 200,000 new cases of leprosy are detected each year, of which approximately 7% are associated with grade-2 disabilities (G2Ds). For achieving leprosy elimination, one of the main challenges will be targeting higher risk groups within endemic communities. Nevertheless, the socioeconomic risk markers of leprosy remain poorly understood. To address this gap we systematically reviewed MEDLINE/PubMed, Embase, LILACS and Web of Science for original articles investigating the social determinants of leprosy in countries with > 1000 cases/year in at least five years between 2006 and 2016. Cohort, case-control, cross-sectional, and ecological studies were eligible for inclusion; qualitative studies, case reports, and reviews were excluded. Out of 1,534 non-duplicate records, 96 full-text articles were reviewed, and 39 met inclusion criteria. 17 were included in random-effects meta-analyses for sex, occupation, food shortage, household contact, crowding, and lack of clean (i.e., treated) water. The majority of studies were conducted in Brazil, India, or Bangladesh while none were undertaken in low-income countries. Descriptive synthesis indicated that increased age, poor sanitary and socioeconomic conditions, lower level of education, and food-insecurity are risk markers for leprosy. Additionally, in pooled estimates, leprosy was associated with being male (RR = 1.33, 95% CI = 1.06-1.67), performing manual labor (RR = 2.15, 95% CI = 0.97-4.74), suffering from food shortage in the past (RR = 1.39, 95% CI = 1.05-1.85), being a household contact of a leprosy patient (RR = 3.40, 95% CI = 2.24-5.18), and living in a crowded household (≥5 per household) (RR = 1.38, 95% CI = 1.14-1.67). Lack of clean water did not appear to be a risk marker of leprosy (RR = 0.94, 95% CI = 0.65-1.35). Additionally, ecological studies provided evidence that lower inequality, better human development, increased healthcare coverage, and cash transfer programs are linked with lower leprosy risks. These findings point to a consistent relationship between leprosy and unfavorable economic circumstances and, thereby, underscore the pressing need of leprosy control policies to target socially vulnerable groups in high-burden countries.

Community-based monitoring of diarrhea in urban Brazilian children: incidence and associated pathogens.

Community-based monitoring was conducted in order to investigate the occurrence of diarrhea in 'sentinel areas' of Salvador, Brazil, and to establish a preliminary profile of the most common pathogens present in children's diarrhea by screening stool samples. This report describes the results obtained from twice weekly home visits to identify and follow diarrhea episodes and testing of carer-requested stool sample collection over a 6-month period. Participants were selected from a large longitudinal study in 21 areas representing the city's poorer socioeconomic and sanitary conditions. Fecal samples were examined for the presence of pathogenic bacteria, viruses and protozoa. The mean incidence of diarrhea was 4.97 episodes per child-year, and longitudinal prevalence was 13.6 days per child-year (3.7%). Pathogens were found in 44% of the fecal samples examined. Bacteria were the most frequently encountered pathogens (isolated in 22% of samples), followed by protozoa (19.5%) and viruses (16%). Viral and bacterial pathogens were associated with episodes of severe diarrhea, while viral and protozoan pathogens were associated with longer episodes. The study demonstrated the importance of a public health monitoring system based on 'sentinel areas'.

Childhood diarrhoea symptoms, management and duration: observations from a longitudinal community study.

This study examined the evolution and duration of diarrhoea episodes observed in a community setting, with regard to symptoms and carers' responses. The study group comprised 1156 children, aged 0-36 months, who were followed-up with twice-weekly home visits in 30 sampling areas in the city of Salvador, northeast Brazil. A total of 2403 diarrhoea episodes (mean duration: 2.9 days) were recorded. The number of soft/liquid motions per day (3.6) did not vary significantly with duration, but other symptoms were more commonly reported in the longer episodes. However, when the data were analysed by day of the episode, rather than the episode's overall duration, the reported frequency of fever and vomiting declined significantly with time. During the course of an episode, rehydration, medication and care-seeking also showed a decline in frequency after the first or second week. As episodes continue, less rehydration and medical care are provided by carers, whereas they ought to be maintained because of the continued purging and cumulative effect of the symptoms. Since most cases of diarrhoea are managed at home, it is important to understand how to encourage better management of the longer episodes, which cause an increasing proportion of mortality in some countries.

Sentinel areas: a monitoring strategy in public health.

Available techniques for monitoring the health situation have proven insufficient, thus leading to a discussion of the need for their improvement based on new data collection strategies allowing for data use by local health systems. This article presents the methodological basis for a strategy to monitor health problems utilizing demarcated intra-urban spaces called "sentinel areas" to collect fundamental social, economic, behavioral, and biological data for public health that allow for a closer approach to the reality of complex social spaces. The authors present an experience that is being developed in Salvador, Bahia, Brazil, to evaluate the epidemiological impact of an environmental sanitation program. They discuss selection criteria for the areas and the potential uses of this strategy allowing for the rapid utilization of epidemiological resources by health services and the timely application of the results to reorient and enhance health intervention practices.

Epidemiologists working together with anthropologists: lessons from a study to evaluate the epidemiological impact of a city-wide sanitation program.

This paper discusses the role of qualitative approaches in epidemiological studies, beginning with a general discussion of epidemiological and anthropological methods. It focuses on a case study of the health impact of an environmental intervention carried out in Salvador, Bahia State, Brazil. Most of the precedent studies fields, based on primary date, use to devote little attention to the methodological and theorethical questions attached to long-term studies. Four specific aspects of this experience are highlighted: (a) drawing up epidemiological study; (b) construction of an observational instrument to measure hygiene habits; (c) an ethnographic study that was carried out before the epidemiological study; (d) observation of the effects of health intervention on health inequalities. Finally, the report details how the findings of qualitative and quantitative studies might be synthesized. It provides a critical overview of follow-up strategies, illustrated with proper examples whenever possible.

Environmental indicators of intra-urban hetererogeneity.

A large number of human diseases are related to poor access to water and sewer systems, inadequate solid waste management and deficient storm water drainage. The goal of this study was to formulate environmental sanitation indicators and classify sanitation conditions in specific sewer basins and their respective neighborhoods. The database used contains information on the following sanitation components in these areas: water supply, sewer systems, urban drainage, road pavement, building typology and public cleaning. Data was analyzed using cluster analysis. The key variable of each component was identified, and eight sewer basins and twenty-three neighborhoods were classified into the following categories: good, regular, and poor. The use of environmental sanitation indicators allows decision makers to identify critical areas and define priorities for improving environmental sanitation conditions.

Factors associated with rotavirus diarrhoea in children living in a socially diverse urban centre in Brazil.

A case-control study, aimed at identifying factors associated with rotavirus diarrhoea cases presenting to health facilities, was conducted in children from low-income and middle-low-income families in Brazil. Cases were 390 children with diarrhoea and rotavirus in stools; controls were 1674 children without diarrhoea presenting to the same facilities. Data were collected by questionnaire and observations during home visits. Explanatory variables were grouped according to a conceptual model of causation. The ORs by non-conditional logistic regression and population-attributable fractions were calculated. Socioeconomic factors contributed a third of cases, followed by contact with diarrhoea cases and by not being breast fed. In cases aged <1 year, not being breast fed was the main determinant, followed by socioeconomic factors, and crowding and contact outside the home; in older children, socioeconomic factors followed by contact inside and outside the home were the main determinants. Environmental and sanitation variables were not associated with diarrhoea in the final model, and socioeconomic factors were only partly mediated by proximal variables. Transmission of rotavirus appears to be mostly by person-to-person contact, and shows marked social differentials not explained by the biological factors studied. The rotavirus vaccine is unlikely to protect against the full range of circulating genotypes of rotavirus, and understanding rotavirus epidemiology remains essential to the development of control policies.