Interaction between vitamin A supplementation and chronic malnutrition on child development.

200 million pre-school age children are not developing properly. Delays in child development are associated with multiple factors. This study aims to analyze if vitamin A supplementation is associated with improved development and how this effect could be mediated by nutritional status. Population-based study surveyed a representative sample of 8000 households, 1232 children 0-35 months, in the state of Ceará, Brazil. The variables analysed included child developmental status, nutritional determinants and confounding factors. The main effects and interactions were evaluated using Cox regressive models. Vitamin A supplementation showed protective effect to delay in cognitive and motor development modified by interaction with nutritional status. While well-nourished supplemented children presented a 67% lower risk of cognitive delay (adjusted PRR = 0·33 [0·21-0·53]), stunted children had no benefit from supplementation (adjusted PRR = 0·97 [0·39-2·40]). Vitamin A supplementation has a protective effect on child development, but not in stunted children. This suggests that supplementation is effective in promoting child development, especially if associated to a joint effort to improve the nutritional status of children, given the importance of this mediator.

Interaction between vitamin A supplementation and chronic malnutrition on child development / Interação entre suplementação de vitamina A e desnutrição crônica no desenvolvimento infantil

Abstract 200 million pre-school age children are not developing properly. Delays in child development are associated with multiple factors. This study aims to analyze if vitamin A supplementation is associated with improved development and how this effect could be mediated by nutritional status. Population-based study surveyed a representative sample of 8000 households, 1232 children 0-35 months, in the state of Ceará, Brazil. The variables analysed included child developmental status, nutritional determinants and confounding factors. The main effects and interactions were evaluated using Cox regressive models. Vitamin A supplementation showed protective effect to delay in cognitive and motor development modified by interaction with nutritional status. While well-nourished supplemented children presented a 67% lower risk of cognitive delay (adjusted PRR = 0·33 [0·21-0·53]), stunted children had no benefit from supplementation (adjusted PRR = 0·97 [0·39-2·40]). Vitamin A supplementation has a protective effect on child development, but not in stunted children. This suggests that supplementation is effective in promoting child development, especially if associated to a joint effort to improve the nutritional status of children, given the importance of this mediator.

Resumo Duzentos milhões de crianças em idade pré-escolar não estão se desenvolvendo adequadamente. Os atrasos no desenvolvimento estão associados a múltiplos fatores. Este estudo pretende analisar se a suplementação de vitamina A está associada a melhor desenvolvimento e a forma como esse efeito pode ser mediado pelo estado nutricional. Estudo de base populacional com amostra de 8.000 famílias, 1.232 crianças 0-35 meses, no estado do Ceará, Brasil. As variáveis analisadas incluíram desenvolvimento, determinantes nutricionais e fatores de confusão. Os efeitos e as interações foram avaliados utilizando modelos regressivos de Cox. A suplementação de vitamina A foi protetora para atraso no desenvolvimento cognitivo e motor modificado pela interação com o estado nutricional. Crianças suplementadas bem nutridas apresentaram um risco 67% menor de atraso cognitivo (PRR ajustado = 0 33 [0 21-0 53]), já as crianças desnutridas não se beneficiaram (PRR ajustado = 0 97 [0 39-2 40]). A suplementação tem um efeito protetor sobre o desenvolvimento, mas não em crianças desnutridas. Isso sugere que a suplementação é eficaz na promoção do desenvolvimento, especialmente se associada a um esforço para melhorar o estado nutricional infantil, dada a importância desse mediador.

Effects of Vitamin A supplementation on child morbidity: a twenty-year time series analysis in the northeastern region of Brazil.

The present study aimed to determine the prevalence of supplementation between 1987 and 2007, and to measure the impact of this on morbidity. Five sequential cross-sectional studies in a 20-year time span were analyzed. Each had a sample of 8,000 domiciles representative of Ceará, in northeastern Brazil. Data were analyzed with descriptive statistics, followed by bivariate and multivariate analyses. Increases in coverage, ranging from 9.6 to 65.8 % were verified, and the study found that the impact of supplementation in reducing morbidity may not be significant. The study also found that supplementation may be associated with higher frequency of certain morbidities (OR 1.8, CI 95 % 1.20-2.95). When the supplementation variable was adjusted for socioeconomic factors, the risk was higher for diarrhea (OR 5.56, CI 95 % 2.63-11.75). The study concluded that in Brazil, vitamin A supplementation may have little benefit in reducing morbidity.