RESUMO
BACKGROUND: Vitamin B12 and folate are key nutrients that help children reach their full potential in growth and development; however, little is known about the status of these vitamins in Brazilian children. OBJECTIVES: To describe the serum concentrations of vitamin B12 and folate, to investigate the association between high folate concentration (HFC) and vitamin B12 deficiency, and to evaluate the association between vitamin B12 and stunting/underweight in Brazilian children aged 6-59 mo. METHODS: Data from 7417 children aged 6-59 mo collected during the Brazilian National Survey on Child Nutrition were used. Serum concentrations of vitamin B12 of <150 pmol/L and folate of <10 nmol/L were classified as deficient, and folate concentrations of >45.3 nmol/L were classified as HFC. Children with length/height-for-age z-score of less than -2 were considered stunted, and those with weight-for-age z-score of less than -2 were underweight. Logistic regression models were performed. RESULTS: In Brazil, 14.2% (95% CI: 12.2, 16.1) of children aged 6-59 mo had vitamin B12 deficiency, 1.1% (95% CI: 0.5, 1.6) had folate deficiency, and 36.9% (95% CI: 33.4, 40.3) had HFC. Vitamin B12 deficiency was higher in children from the northern region of Brazil (28.5%), between 6 and 24 mo (25.3%), whose mothers had lower formal education (0-7 y; 18.7%). Children with HFC had 62% lower odds (OR: 0.38; 95% CI: 0.27, 0.54) of vitamin B12 deficiency than those with normal/deficient folate. Children with vitamin B12 deficiency and normal/deficient folate had higher odds of stunting (OR: 1.58; 95% CI: 1.02, 2.43) than children without vitamin B12 deficiency and normal/deficient folate. CONCLUSIONS: Vitamin B12 deficiency is a public health problem among Brazilian children aged <2 y with vulnerable socioeconomic status. HFC was inversely associated with vitamin B12 deficiency, and lower odds of stunting were observed in children with HFC and vitamin B12 deficiency than in those with vitamin B12 deficiency and normal/deficient folate.
Assuntos
Deficiência de Ácido Fólico , Deficiência de Vitamina B 12 , Feminino , Humanos , Criança , Ácido Fólico , Estado Nutricional , Brasil/epidemiologia , Magreza , Deficiência de Vitamina B 12/epidemiologia , Vitamina B 12 , Deficiência de Ácido Fólico/epidemiologia , Transtornos do Crescimento/epidemiologiaRESUMO
This article aims to present methodological aspects on the collection, analyses, coverage, challenges, and the lessons learned from laboratory assessment of micronutrients on the Brazilian National Survey on Child Nutrition (ENANI-2019). This is a household survey on a probability sample of children under five years of age from 123 Brazilian municipalities in all 26 states and the Federal District. Blood samples were drawn by venipuncture at the homes of children 6 to 59 months of age. This procedure was performed by experienced phlebotomists from the laboratories located in the selected municipalities and scheduled in advance. Blood and serum levels were measured for biomarkers of nutritional status, using the services of a clinical test laboratory with nationwide coverage, for the following micronutrients: iron (hemoglobin and ferritin), zinc, selenium, folic acid, and vitamins A, B1, B6, B12, D, and E. C-reactive protein was analyzed as a marker of inflammation. A barcode identifier was used to track the blood samples and to link the biochemical test results to the other data collected in the survey. A total of 14,558 children were studied. Of the 12,598 eligible children, 8,829 (70.1%) had blood samples drawn. Of the total number of children who had samples drawn, 91.8% (n = 8,025) have results for at least nine of the 12 analyses performed. Coverage of the analysis varied from 95% (for vitamins A and E) to 84.2% (for folic acid). Aliquots of whole blood and serum were stored in a biorepository for future analyses. The results of this pioneering study in the country will back the formulation and, when necessary, the reorientation of public policies in food and nutrition.
Assuntos
Micronutrientes , Oligoelementos , Brasil , Criança , Fenômenos Fisiológicos da Nutrição Infantil , Pré-Escolar , Humanos , Estado NutricionalRESUMO
This article aims to present methodological aspects on the collection, analyses, coverage, challenges, and the lessons learned from laboratory assessment of micronutrients on the Brazilian National Survey on Child Nutrition (ENANI-2019). This is a household survey on a probability sample of children under five years of age from 123 Brazilian municipalities in all 26 states and the Federal District. Blood samples were drawn by venipuncture at the homes of children 6 to 59 months of age. This procedure was performed by experienced phlebotomists from the laboratories located in the selected municipalities and scheduled in advance. Blood and serum levels were measured for biomarkers of nutritional status, using the services of a clinical test laboratory with nationwide coverage, for the following micronutrients: iron (hemoglobin and ferritin), zinc, selenium, folic acid, and vitamins A, B1, B6, B12, D, and E. C-reactive protein was analyzed as a marker of inflammation. A barcode identifier was used to track the blood samples and to link the biochemical test results to the other data collected in the survey. A total of 14,558 children were studied. Of the 12,598 eligible children, 8,829 (70.1%) had blood samples drawn. Of the total number of children who had samples drawn, 91.8% (n = 8,025) have results for at least nine of the 12 analyses performed. Coverage of the analysis varied from 95% (for vitamins A and E) to 84.2% (for folic acid). Aliquots of whole blood and serum were stored in a biorepository for future analyses. The results of this pioneering study in the country will back the formulation and, when necessary, the reorientation of public policies in food and nutrition.
O objetivo deste artigo é apresentar os aspectos metodológicos referentes à coleta e análise de dados laboratoriais do Estudo Nacional de Alimentação e Nutrição Infantil (ENANI-2019), a cobertura das análises laboratoriais, os desafios enfrentados e as lições aprendidas. Trata-se de um inquérito populacional de base domiciliar de crianças menores de cinco anos realizado em 123 municípios dos 26 estados da Federação e o Distrito Federal. A coleta de sangue por punção venosa foi realizada em domicílio em crianças com idade entre 6 e 59 meses, por coletador experiente de laboratório(s) existente(s) nos municípios amostrados. Foram determinadas as concentrações sanguíneas e séricas de biomarcadores do estado nutricional utilizando os serviços de um laboratório de análises clínicas com abrangência nacional para os seguintes micronutrientes: ferro (hemoglobina e ferritina), zinco, selênio, ácido fólico, vitaminas A, B1, B6, B12, D e E. A proteína C reativa foi analisada como marcador de inflamação. Um código de barras identificador das amostras de sangue foi utilizado para o rastreio da amostra e para a junção dos resultados dos exames bioquímicos com os demais dados coletados na pesquisa. Foram estudadas 14.558 crianças. Das 12.598 elegíveis, 8.829 (70,1%) realizaram coleta de sangue. Do total de crianças que realizaram coleta de sangue, 91,8% (n = 8.025) têm resultados para pelo menos nove das 12 análises realizadas. A cobertura por análise variou de 95% (para vitaminas A e E) a 84,2% (para ácido fólico). Os resultados deste estudo pioneiro subsidiarão a formulação e, quando for o caso, o redirecionamento de políticas públicas de alimentação e nutrição.
El objetivo de este artículo es presentar aspectos metodológicos, respecto a la recogida y análisis de datos de laboratorio del Estudio Nacional de Alimentación y Nutrición Infantil (ENANI-2019), así como la cobertura de los mismos, los desafíos enfrentados y lecciones aprendidas. Se trata de una encuesta poblacional de base domiciliaria con niños menores de cinco años, realizada en 123 municipios de los 26 estados de la Federación y el Distrito Federal. La recogida de sangre por punción venosa se realizó en domicilios con niños, de edades comprendidas entre los 6 y los 59 meses, con la intervención de un flebotomista con experiencia en laboratorio(s) existente(s) en los municipios de muestra. Se determinaron las concentraciones sanguíneas y séricas de biomarcadores del estado nutricional, utilizando los servicios de un laboratorio de análisis clínicos con alcance nacional para los siguientes micronutrientes: hierro (hemoglobina y ferritina), zinc, selenio, ácido fólico, vitaminas A, B1, B6, B12, D y E. La proteína C reactiva se analizó como marcador de inflamación. Un código de barras identificador de las muestras de sangre se utilizó para el rastreo de la muestra y para la conjunción de los resultados de los exámenes bioquímicos con los demás datos recogidos en la investigación. Se estudiaron 14.558 niños. De los 12.598 elegibles, a 8.829 (70,1%) se les sacó sangre. Del total de niños, a quienes se les tomó muestras de sangre, un 91,8% (n = 8.025) obtuvieron resultados para por lo menos nueve de los 12 análisis realizados. La cobertura por análisis varió de un 95% (para vitaminas A y E), a un 84,2% (para ácido fólico). Los resultados de este estudio pionero apoyarán la formulación y, cuando fuera necesario, la redirección de políticas públicas de alimentación y nutrición.
