Acute viral bronchiolitis and risk of asthma in schoolchildren: analysis of a Brazilian newborn cohort / Bronquiolite viral aguda e risco de asma em escolares: análise de coorte de recém-nascidos brasileiros

Abstract Objective: To verify whether the occurrence of acute viral bronchiolitis in the first year of life constitutes a risk factor for asthma at age 6 considering a parental history of asthma. Methods: Cross-sectional study in a cohort of live births. A standardized questionnaire of the International Study of Asthma and Allergies in Childhood was applied to the mothers to identify asthma in children at the age of 6 years. Acute viral bronchiolitis diagnosis was performed by maternal report of a medical diagnosis and/or presence of symptoms of coryza accompanied by cough, tachypnea, and dyspnea when participants were 3, 6, 9, and 12 months. Socioeconomic, environmental data, parental history of asthma, and data related to pregnancy were collected in the first 72 h of life of the newborn and in prospective home visits by trained interviewers. The association between acute viral bronchiolitis and asthma was evaluated by logistic regression analysis and potential modifier effect of parental history was verified by introducing an interaction term into the adjusted logistic regression model. Results: Prevalence of acute viral bronchiolitis in the first year of life was 68.6% (461). The occurrence of acute viral bronchiolitis was a risk factor for asthma at 6 years of age in children with parental history of asthma OR: 2.66, 95% CI (1.10-6.40), modifier effect p = 0.002. Parental history of asthma OR: 2.07, 95% CI (1.29-3.30) and male gender OR: 1.69, 95% CI, (1.06-2.69) were other identified risk factors for asthma. Conclusion: Acute viral bronchiolitis in the first year of life is a risk factor for asthma in children with parental history of asthma.

Resumo Objetivo: Verificar se a ocorrência de bronquiolite viral aguda (BVA) no primeiro ano de vida constitui fator de risco para asma aos seis anos considerando a história parental de asma. Métodos: Estudo de corte transversal aninhado a uma coorte de nascidos vivos. O questionário padronizado do International Study of Asthma and Allergies in Children (ISAAC) foi aplicado às mães para identificar asma nas crianças de seis anos. O diagnóstico de BVA foi feito por relato materno de diagnóstico médico e/ou presença de sintomas de coriza acompanhados de tosse, taquipneia e dispneia quando os participantes tinham três, seis, nove e 12 meses. Dados socioeconômicos, ambientais, história parental de asma e referentes à gestação foram coletados nas primeiras 72 horas de vida do recém-nascido e em visitas domiciliares prospectivas por entrevistadores treinados. Associação entre BVA e asma foi avaliada por análise de regressão logística e potencial efeito modificador da história parental verificado pela introdução do termo de interação no modelo de regressão logística ajustada. Resultados: A prevalência de BVA no primeiro ano de vida foi 68,6% (461). A ocorrência de BVA foi fator de risco para asma aos seis anos em crianças com história parental de asma OR: 2,66 (1,10-6,40), efeito modificador p = 0,002. História parental de asma OR: 2,07 IC95% (1,29-3,30) e sexo masculino OR: 1,69 IC95% (1,06-2,69) foram outros fatores de risco identificados para asma. Conclusão: BVA no primeiro ano de vida é fator de risco para asma em crianças com história parental de asma.

Acute viral bronchiolitis and risk of asthma in schoolchildren: analysis of a Brazilian newborn cohort.

OBJECTIVE: To verify whether the occurrence of acute viral bronchiolitis in the first year of life constitutes a risk factor for asthma at age 6 considering a parental history of asthma. METHODS: Cross-sectional study in a cohort of live births. A standardized questionnaire of the International Study of Asthma and Allergies in Childhood was applied to the mothers to identify asthma in children at the age of 6 years. Acute viral bronchiolitis diagnosis was performed by maternal report of a medical diagnosis and/or presence of symptoms of coryza accompanied by cough, tachypnea, and dyspnea when participants were 3, 6, 9, and 12 months. Socioeconomic, environmental data, parental history of asthma, and data related to pregnancy were collected in the first 72h of life of the newborn and in prospective home visits by trained interviewers. The association between acute viral bronchiolitis and asthma was evaluated by logistic regression analysis and potential modifier effect of parental history was verified by introducing an interaction term into the adjusted logistic regression model. RESULTS: Prevalence of acute viral bronchiolitis in the first year of life was 68.6% (461). The occurrence of acute viral bronchiolitis was a risk factor for asthma at 6 years of age in children with parental history of asthma OR: 2.66, 95% CI (1.10-6.40), modifier effect p=0.002. Parental history of asthma OR: 2.07, 95% CI (1.29-3.30) and male gender OR: 1.69, 95% CI, (1.06-2.69) were other identified risk factors for asthma. CONCLUSION: Acute viral bronchiolitis in the first year of life is a risk factor for asthma in children with parental history of asthma.

Trends in breastfeeding indicators in a city of northeastern Brazil / Tendência dos indicadores de aleitamento materno em uma cidade do Nordeste brasileiro

OBJECTIVE: To investigate trends in breastfeeding indicators in the city of Feira de Santana, Brazil, and to identify population characteristics that might have influenced this trend. METHODS: Three methodologically comparable cross-sectional surveys performed in 1996, 2001, and 2009 were analyzed. These involved 2,159, 2,319, and 1,471 children younger than 1 year of age who were vaccinated in national multivaccination campaigns in the respective years. A standardized questionnaire was used, containing closed questions on consumption of breast milk and other foods on the day before the survey, along with questions regarding the characteristics of the population. RESULTS: The annual growth of the breastfeeding indicators was 2.1% for breastfeeding in the first hour of life (from 52.2% to 68.9%); 1.1% for breastfeeding among children aged 9 to 12 months (from 45% to 59.6%); and 0.8% for exclusive breastfeeding among infants younger than 6 months (from 36.9% to 47.4%). The median duration of exclusive breastfeeding increased from 52.3 to 84.3 days, and overall breastfeeding from 278 to 376 days. Some changes in the characteristics of the population were observed, which may have positively influenced the evolution of the breastfeeding indicators (better schooling level among the mothers, less use of dummies/pacifiers, and lower proportions of adolescent mothers), or negatively (greater proportions of primiparous mothers and cesarean deliveries, and lower frequency of births in Baby-Friendly Hospitals). CONCLUSION: There were significant advances in breastfeeding indicators, although they are still far from ideal. Changes observed in population characteristics may have positively or negatively influenced this evolution. .

OBJETIVO: Verificar a tendência dos indicadores de aleitamento materno (AM) em Feira de Santana, Brasil, e identificar características da população que possam ter influenciado essa tendência. MÉTODOS: Procedeu-se à análise de três inquéritos transversais, metodologicamente comparáveis, feitos em 1996, 2001 e 2009, que envolveram 2.159, 2.319 e 1.471 menores de um ano vacinados na campanha nacional de multivacinação desses anos. Usou-se questionário que continha questões sobre o consumo de leite materno e outros alimentos no dia anterior ao inquérito, além de perguntas sobre características da população. RESULTADOS: O acréscimo anual nos indicadores de AM foi de 2,1 pontos percentuais para o AM na primeira hora de vida (de 52,2% para 68,9%); 1,1 ponto para o AM em crianças de nove a 12 meses (de 45% para 59,6%); e de 0,8 ponto para o AM exclusivo (AME) em menores de seis meses (de 36,9% para 47,4%). A duração mediana do AME aumentou de 52 para 84 dias e a de AM de 278 para 376 dias. Observaram-se mudanças nas características da população, as quais podem ter influenciado a evolução dos indicadores do AM de forma positiva (melhor escolaridade das mães, decréscimo no uso de chupeta e menor prevalência de mães adolescentes) ou negativa (maior proporção de mães primíparas e de cesarianas e menor frequência de nascimentos em Hospital Amigo da Criança). CONCLUSÃO: Houve avanços significativos nos indicadores de AM em Feira de Santana, embora ainda estejam longe do ideal. Mudanças observadas nas características da população podem ter influenciado positiva ou negativamente essa evolução. .

Maternal obesity, environmental factors, cesarean delivery and breastfeeding as determinants of overweight and obesity in children: results from a cohort.

BACKGROUND: Overweight and obesity are a public health problem with a multifactorial aetiology. The objective of this study was to evaluate risk factors for overweight and obesity in children at 6 years of age, including type of delivery and breastfeeding. METHODS: This study relates to a cohort of 672 mother-baby pairs who have been followed from birth up to 6 years of age. The sample included mothers and infants seen at all ten maternity units in a large Brazilian city. Genetic, socioeconomic, demographic variables and postnatal characteristics were analyzed. The outcome analyzed was overweight and/or obesity defined as a body mass index greater than or equal to +1 z-score. The sample was stratified by breastfeeding duration, and a descriptive analysis was performed using a hierarchical logistic regression. P-values of <0.05 were considered significant. RESULTS: Prevalence rates (PR) of overweight and obesity among the children were 15.6% and 12.9%, respectively. Among the subset of breastfed children, factors associated with the outcome were maternal overweight and/or obesity (PR 1.92; 95% confidence interval "95% CI" 1.15-3.24) and lower income (PR 0.50; 95% CI 0.29-0.85). Among children who had not been breastfed or had been breastfed for shorter periods (less than 12 months), predictors were mothers with lower levels of education (PR 0.39; 95% CI 0.19-0.78), working mothers (PR 1.83; 95% CI 1.05-3.21), caesarean delivery (PR 1.98; 95% CI 1.14 - 3.50) and maternal obesity (PR 3.05; 95% CI 1.81 - 5.25). CONCLUSIONS: Maternal obesity and caesarean delivery were strongly associated with childhood overweight and/or obesity. Lower family income and lower levels of education were identified as protective factors. Breastfeeding duration appeared to modify the association between overweight/obesity and the other predictors studied.

Trends in breastfeeding indicators in a city of northeastern Brazil.

OBJECTIVE: To investigate trends in breastfeeding indicators in the city of Feira de Santana, Brazil, and to identify population characteristics that might have influenced this trend. METHODS: Three methodologically comparable cross-sectional surveys performed in 1996, 2001, and 2009 were analyzed. These involved 2,159, 2,319, and 1,471 children younger than 1 year of age who were vaccinated in national multivaccination campaigns in the respective years. A standardized questionnaire was used, containing closed questions on consumption of breast milk and other foods on the day before the survey, along with questions regarding the characteristics of the population. RESULTS: The annual growth of the breastfeeding indicators was 2.1% for breastfeeding in the first hour of life (from 52.2% to 68.9%); 1.1% for breastfeeding among children aged 9 to 12 months (from 45% to 59.6%); and 0.8% for exclusive breastfeeding among infants younger than 6 months (from 36.9% to 47.4%). The median duration of exclusive breastfeeding increased from 52.3 to 84.3 days, and overall breastfeeding from 278 to 376 days. Some changes in the characteristics of the population were observed, which may have positively influenced the evolution of the breastfeeding indicators (better schooling level among the mothers, less use of dummies/pacifiers, and lower proportions of adolescent mothers), or negatively (greater proportions of primiparous mothers and cesarean deliveries, and lower frequency of births in Baby-Friendly Hospitals). CONCLUSION: There were significant advances in breastfeeding indicators, although they are still far from ideal. Changes observed in population characteristics may have positively or negatively influenced this evolution.

Duration of exclusive breastfeeding in a Brazilian population: new determinants in a cohort study.

BACKGROUND: Determinants of the duration of exclusive breastfeeding (EBF) differ in effect and magnitude across populations. The present study aimed to identify factors associated with discontinuation of EBF in a municipality in northeastern Brazil, including variables that have received little or no attention in previous literature. METHODS: This cohort study involved 1,344 mother-child pairs selected from maternity hospitals in Feira de Santana, Bahia, Brazil. Subjects were followed up for 6 months through monthly home visits, and discontinuation of EBF was recorded. Possible determinants were tested using Cox's four-level hierarchical survival model, taking into consideration the temporal proximity of the predisposing factors to interruption of EBF. Median duration of EBF was estimated using Kaplan-Meier's survival curve. RESULTS: Median duration of EBF was 89 days. Out of the 19 variables tested, 9 showed an association with EBF cessation; of these, two had never been evaluated in Brazilian studies, namely, mother partner's appreciation for breastfeeding (hazard ratio [HR] 0.62; 95% confidence interval [95% CI] 0.48-0.79) and limiting the number of nighttime feeds at the breast (HR 1.58; 95% CI 1.11-2.23). Another two variables that had been previously evaluated, but had never been described as determinants of discontinuation of EBF showed association: presence of cracked nipples (HR 2.54; 95% CI 2.06-3.13) and prenatal care provided by public services (HR 1.34; 95% CI 1.17-1.55). Other variables showing associations with the outcome were: guidance on breastfeeding received at the hospital (HR 0.80; 95% CI 0.68-0.92), birth in a Baby-Friendly Hospital (HR 0.85; 95% CI 0.73-0.99), less than or equal to 8 years of maternal schooling (HR 1.34, 95% CI 1.17-1.53), mother working outside the home (HR 1.73; 95% CI 1.53-1.95), and use of a pacifier (HR 1.40; 95% CI 1.14-1.71). CONCLUSIONS: The study confirmed that the factors associated with EBF duration are multiple, variable, and dependent on the population being evaluated. Characteristics that had never been previously evaluated or described, at least in Brazilian studies, behaved as determinants of EBF in the present study, and thus allow to expand the existing list of factors determining this practice.

Determinants of breastfeeding initiation within the first hour of life in a Brazilian population: cross-sectional study.

BACKGROUND: Breastfeeding within the first hour of life is a potential mechanism for health promotion. The purpose of this study was to evaluate the prevalence of breastfeeding initiation within the first hour of life in Feira de Santana, Bahia, Brazil, between 2004 and 2005, and investigate the influence of maternal, child and prenatal factors on this practice. METHODS: This is a cross-sectional study extracted from the results of a contemporary cohort conducted in 10 maternity hospitals in the city of Feira de Santana, Bahia, Brazil. A group of 1,309 mother-child pairs was included in the study. Information about mother's and baby's characteristics, pregnancy, birth, and time of breastfeeding initiation was collected in the first 72 hours after delivery, through interview with mothers and hospital records. The data gathered were stored and analyzed using the SPSS 16.0 and R 8.0. The chi-square test and binary logistic regression analysis were used to examine the relationship between breastfeeding within the first hour and different variables. RESULTS: 47.1% of the mothers initiated breastfeeding within the first hour after birth. Early initiation of breastfeeding was associated with birth at full term pregnancy (adjusted Prevalence Ratio 1.43; 95% confidence interval 1.10 to 2.00), mothers who received prenatal guidance regarding the advantages of breastfeeding (aPR1.23; 95% CI 1.11 to 1.41) and vaginal delivery (aPR 2.78; 95% CI 2.38 to 3.23). CONCLUSIONS: In order to improve the rates of breastfeeding within the first hour of life, health care professionals must promote the factors favoring this practice such as prenatal guidance regarding the advantages of breastfeeding, vaginal delivery and full term birth, and stimulate this practice in vulnerable situations such as mothers with cesarean section and preterm birth.

Factors predicting early discontinuation of exclusive breastfeeding in the first month of life.

OBJECTIVE: To investigate factors associated with discontinuation of exclusive breastfeeding in the first month of lactation, in the city of Feira de Santana, Brazil. METHODS: Cohort study with follow-up of 1,309 mother-child pairs selected from all maternities in the municipality. Data were collected in hospital and in home visits during the first month of life. Logistic regression analysis was used to examine the relationship between outcome and variables of interest. RESULTS: Lack of prior breastfeeding experience (PR 1.24; 95%CI 1.75-1.43), cracked nipples (PR 1.25; 95%CI 1.09-1.43), use of fixed breastfeeding schedules (PR 1.42; 95%CI 1.09-1.84) and pacifier use (PR 1.53; 95%CI 1.34-1.76) were identified as factors predicting discontinuation of exclusive breastfeeding. CONCLUSIONS: Measures to prevent early discontinuation of exclusive breastfeeding must focus on women without breastfeeding experience and include prevention of nipple trauma, encourage breastfeeding on demand, and discourage the use of pacifiers.

Determinants of overweight in children under 4 years of age.

OBJECTIVES: To describe the prevalence of and factors associated with overweight in children under 4 years of age in Feira de Santana, state of Bahia, Brazil. METHODS: Cross-sectional study nested within a birth cohort of 793 children born in Feira de Santana, Brazil. Independent variables were related to infant characteristics, social and demographic factors, maternal reproductive aspects, and diet of the child at age 4 months. The dependent variable was nutritional status, as assessed by weight-for-height ratio compared to Multicentre Growth Reference Study standards and obtained with the use of the software ANTHRO. Z-scores of -2 and +2 above or below the median for the reference population were established as normality cutoff points. Child height and weight were measured with an anthropometer and digital scales, respectively; all measurements were taken in triplicate. The study was approved by the Research Ethics Committee of the Universidade Estadual de Feira de Santana (CEP/UEFS), under registration number 096/2006. RESULTS: The prevalence of overweight was 12.5%. Adequate birth weight (RR 2.75; 95%CI 1.50-5.05), primiparity (RR 1.61; 95%CI 1.09-2.35), and maternal employment outside the home at age 4 months (RR 1.73; 95%CI 1.16-2.59) were associated with overweight. CONCLUSIONS: In this study, adequate birth weight, primiparity and maternal employment outside the home were associated with overweight in children. The rate of overweight found, which surpassed that reported by other studies conducted across the country (including Bahia), point to a risk of child obesity in Feira de Santana.

Fatores determinantes do sobrepeso em crianças menores de 4 anos de idade / Determinants of overweight in children under 4 years of age

OBJETIVOS: Descrever a prevalência e os fatores determinantes do sobrepeso de crianças menores de 4 anos de idade de Feira de Santana (BA). MÉTODOS: Estudo transversal aninhado em uma coorte de nascidos (n = 793) em Feira de Santana. As variáveis independentes foram relacionadas às características das crianças, aos fatores sociodemográficos e reprodutivos maternos e à alimentação da criança aos 4 meses. A variável dependente foi o sobrepeso avaliado pelo índice peso/estatura, comparado ao padrão do Multicentre Growth Reference Study de 2006. Adotaram-se os pontos de corte de normalidade -2 e +2 escore z em relação à mediana da população de referência. O estudo foi aprovado pelo Comitê de Ética em Pesquisa da Universidade Estadual de Feira de Santana, sob registro nº 096/2006. RESULTADOS: A prevalência de sobrepeso observada foi de 12,5 por cento. Características associadas positivamente ao sobrepeso: peso adequado ao nascer (razão de prevalência 2,75; IC95 por cento 1,50-5,05), primiparidade (razão de prevalência 1,61; IC95 por cento 1,09-2,35) e trabalho materno fora de casa aos 4 meses de idade da criança (razão de prevalência 1,73; IC95 por cento 1,16-2,59). CONCLUSÕES: No presente estudo, peso adequado ao nascer, primiparidade e trabalho materno aos 4 meses de vida da criança se associaram com o sobrepeso infantil. A taxa de sobrepeso superou os resultados de outros estudos no país, inclusive em outros municípios baianos, sinalizando para o risco de obesidade e seus comprometimentos a que as crianças em Feira de Santana podem estar submetidas.

OBJECTIVES: To describe the prevalence of and factors associated with overweight in children under 4 years of age in Feira de Santana, state of Bahia, Brazil. METHODS: Cross-sectional study nested within a birth cohort of 793 children born in Feira de Santana, Brazil. Independent variables were related to infant characteristics, social and demographic factors, maternal reproductive aspects, and diet of the child at age 4 months. The dependent variable was nutritional status, as assessed by weight-for-height ratio compared to Multicentre Growth Reference Study standards and obtained with the use of the software ANTHRO. Z-scores of -2 and +2 above or below the median for the reference population were established as normality cutoff points. Child height and weight were measured with an anthropometer and digital scales, respectively; all measurements were taken in triplicate. The study was approved by the Research Ethics Committee of the Universidade Estadual de Feira de Santana (CEP/UEFS), under registration number 096/2006. RESULTS: The prevalence of overweight was 12.5 percent. Adequate birth weight (RR 2.75; 95 percentCI 1.50-5.05), primiparity (RR 1.61; 95 percentCI 1.09-2.35), and maternal employment outside the home at age 4 months (RR 1.73; 95 percentCI 1.16-2.59) were associated with overweight. CONCLUSIONS: In this study, adequate birth weight, primiparity and maternal employment outside the home were associated with overweight in children. The rate of overweight found, which surpassed that reported by other studies conducted across the country (including Bahia), point to a risk of child obesity in Feira de Santana.