Darci Neves dos Santos

Ambiente familiar e desenvolvimento cognitivo infantil: uma abordagem epidemiológica

OBJETIVO: Analisar a associacao entre a qualidade do estimulo domestico e o desempenho cognitivo infantil, identificando o impacto da escolaridade materna sobre a qualidade dessa estimulacao. METODOS: Estudo de corte transversal, com 350 criancas entre 17 e 42 meses, examinadas em 1999, em areas centrais e perifericas de Salvador, Estado da Bahia. Utilizou-se um questionario socioeconomico, o inventario Home Observation for Measurement of the Environment Scale (HOME) para mensurar a estimulacao no ambiente familiar, e a escala Bayley de desenvolvimento infantil. Foram realizadas analises univariadas e multiplas, por meio da regressao linear, considerando nivel de significância de 5%. RESULTADOS: Encontrou-se associacao positiva (beta=0,66) e estatisticamente significante entre a qualidade da estimulacao no ambiente domestico e o desempenho cognitivo infantil. Parte do efeito da estimulacao sobre a cognicao foi mediada pela condicao materna de trabalho e seu nivel de escolaridade. Verificou-se que as criancas ocupando as primeiras ordens de nascimento, convivendo com reduzido numero de menores de cinco anos, usufruem de melhor qualidade da estimulacao no ambiente domestico. Esse padrao de estimulacao se mantem entre criancas convivendo com seus pais, cujas maes possuem melhor escolaridade, trabalham fora e convivem com companheiros no ambiente familiar. CONCLUSOES: Confirma-se a importância da qualidade do estimulo domestico para o desenvolvimento cognitivo infantil, alem do relevante papel das condicoes materiais e dinâmica familiar. Os achados apontam a pertinencia de acoes de intervencao que favorecam a qualidade do ambiente e da relacao cuidador-crianca para o desenvolvimento cognitivo.

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

Summary 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

BackgroundThere is evidence that poverty, health and nutrition affect childrens 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.MethodsThis 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.ResultsUnfavourable 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.ConclusionChildrens 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.

Cross-national differences in questionnaires do not necessarily reflect comparable differences in disorder prevalence.

PurposeTo examine whether the widely used Strengths and Difficulties Questionnaire (SDQ) can validly be used to compare the prevalence of child mental health problems cross nationally.MethodsWe used data on 29,225 5- to 16-year olds in eight population-based studies from seven countries: Bangladesh, Brazil, Britain, India, Norway, Russia and Yemen. Parents completed the SDQ in all eight studies, teachers in seven studies and youth in five studies. We used these SDQ data to calculate three different sorts of “caseness indicators” based on (1) SDQ symptoms, (2) SDQ symptoms plus impact and (3) an overall respondent judgement of ‘definite’ or ‘severe’ difficulties. Respondents also completed structured diagnostic interviews including extensive open-ended questions (the Development and Well-Being Assessment, DAWBA). Diagnostic ratings were all carried out or supervised by the DAWBA’s creator, working in conjunction with experienced local professionals.ResultsAs judged by the DAWBA, the prevalence of any mental disorder ranged from 2.2% in India to 17.1% in Russia. The nine SDQ caseness indicators (three indicators times three informants) explained 8–56% of the cross-national variation in disorder prevalence. This was insufficient to make meaningful prevalence estimates since populations with a similar measured prevalence of disorder on the DAWBA showed large variations across the various SDQ caseness indicators.ConclusionsThe relationship between SDQ caseness indicators and disorder rates varies substantially between populations: cross-national differences in SDQ indicators do not necessarily reflect comparable differences in disorder rates. More generally, considerable caution is required when interpreting cross-cultural comparisons of mental health, particularly when these rely on brief questionnaires.

Caracterização dos usuários e dos serviços prestados por Centros de Atenção Psicossocial Infanto-Juvenil

This study aimed to provide an understanding of diagnosis, demographic characteristics, and treatment procedures for children and adolescents attending Psychosocial Care Centers (CAPSIS) in Brazil, 2003. It was a cross-sectional descriptive study using secondary data. The analysis considered three groups of variables related to: (a) the nature of the services; (b) patient profile; and (c) types of care. Seven CAPSIS that had recorded their procedures during all 12 months of 2003 participated in the study. The units involved treated 1,456 individuals, 62.8% of whom were males 11-13 years of age. Nearly half (49.3%) were treated in non-intensive care. The most frequent diagnoses were behavioral and emotional disorders (44.5%). There was no record of treatment related to use of psychoactive substances. The proportion of severe disorders was 19.4%. The CAPSIS operate in similar fashion to older outpatient units, but treat a variety of problems, creating a record according to types of activities. These services fill a historical gap in public mental health care for children and adolescents.

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

BackgroundThe 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.Methods1445 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.ResultsCommon 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).ConclusionsNon-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.

Behavior problems and prevalence of asthma symptoms among Brazilian children.

Objective Asthma is the most common chronic disease in childhood and has been designated a public health problem due to the increase in its prevalence in recent decades, the amount of health service expenditure it absorbs and an absence of consensus about its etiology. The relationships among psychosocial factors and the occurrence, symptomatology, and severity of asthma have recently been considered. There is still controversy about the association between asthma and a childs mental health, since the pathways through which this relationship is established are complex and not well researched. This study aims to investigate whether behavior problems are associated with the prevalence of asthma symptoms in a large urban center in Latin America. Methods It is a cross-section study of 869 children between 6 and 12 years old, residents of Salvador, Brazil. The International Study of Allergy and Asthma in Childhood (ISAAC) instrument was used to evaluate prevalence of asthma symptoms. The Child Behavior Checklist (CBCL) was employed to evaluate behavioral problems. Results 19.26% (n = 212) of the children presented symptoms of asthma. 35% were classified as having clinical behavioral problems. Poissons robust regression model demonstrated a statistically significant association between the presence of behavioral problems and asthma symptoms occurrence (PR: 1.43; 95% CI: 1.10–1.85). Conclusion These results suggest an association between behavioral problems and pediatric asthma, and support the inclusion of mental health care in the provision of services for asthma morbidity.

Determinants of early cognitive development: hierarchical analysis of a longitudinal study

The study describes the relationship between anthropometric status, socioeconomic conditions, and quality of home environment and child cognitive development in 320 children from 20 to 42 months of age, randomly selected from 20,000 households that represent the range of socioeconomic and environmental conditions in Salvador, Bahia, Northeast Brazil. The inclusion criterion was to be less than 42 months of age between January and July 1999. Child cognitive development was assessed using the Bayley Scales for Infant Development, and the Home Observation for Measurement of the Environment Inventory (HOME) was applied to assess quality of home environment. Anthropometric status was measured using the indicators weight/age and height/age ratios (z-scores), and socioeconomic data were collected through a standard questionnaire. Statistical analysis was conducted through univariate and hierarchical linear regression. Socioeconomic factors were found to have an indirect impact on early cognitive development mediated by the childs proximal environment factors, such as appropriate play materials and games available and school attendance. No independent association was seen between nutritional status and early cognitive development.

Hygiene, atopy and wheeze-eczema-rhinitis symptoms in schoolchildren from urban and rural Ecuador

Background Rural residence is protective against atopy and wheeze–rhinitis–eczema symptoms in developed countries, an effect attributed to farming and poor hygiene exposures. There are few data from developing countries addressing this question. We compared atopy and wheeze–rhinitis–eczema symptoms between urban and rural Ecuador, and explored the effects of farming and poor hygiene exposures. Methods We performed cross sectional studies of schoolchildren living in rural and urban Ecuador. Data on symptoms and farming/hygiene exposures were collected by parental questionnaire, atopy by allergen skin prick test reactivity and geohelminth infections by stool examinations. Results Among 2526 urban and 4295 rural schoolchildren, prevalence was: atopy (10.0% vs 12.5%, p=0.06), wheeze (9.4% vs 10.1%, p=0.05), rhinitis (8.1% vs 6.4%, p=0.02) and eczema (5.9% vs 4.7%, p=0.06). A small proportion of symptoms were attributable to atopy (range 3.9–10.7%) with greater attributable fractions for respiratory symptoms observed in urban schoolchildren. Respiratory symptoms were associated with poor hygiene/farming exposures: wheeze with lack of access to potable water; and rhinitis with household pets, no bathroom facilities and contact with large farm animals. Birth order was inversely associated with respiratory symptoms. Area of residence and atopy had few effects on these associations. Conclusions Urban schoolchildren living in Ecuador have a similar prevalence of atopy, eczema and wheeze but a higher prevalence of rhinitis compared with rural children. Some farming and poor hygiene exposures were associated with an increase in the prevalence of wheeze or rhinitis while birth order was inversely associated with these symptoms.

Structural equation modeling in epidemiology

Structural equation modeling (SEM) is an important statistical tool for evaluating complex relations in several research areas. In epidemiology, the use and discussion of SEM have been limited thus far. This article presents basic principles and concepts in SEM, including an application using epidemiological data analysis from a study on the determinants of cognitive development in young children, considering constructs related to organization of the childs home environment, parenting style, and the childs health status. The relations between the constructs and cognitive development were measured. The results showed a positive association between psychosocial stimulus at home and cognitive development in young children. The article presents the contributions by SEM to epidemiology, highlighting the need for an a priori theoretical model for improving the study of epidemiological questions from a new perspective.