Análise crítica de estudos brasileiros sobre deficiência de vitamina A no grupo materno-infantil

Vitamin A deficiency in Brazilian Children younger than 5 years old: a systematic review

Abstract Objectives: to examine the nutritional status of vitamin A in Brazilian children under 5 years old, delimiting their deficiency and associated factors. Methods: this is a systematic review of articles published between 2008 and 2018, using the SciELO, Bireme, and PubMed electronic databases. A validated instrument critically evaluated the studies. The summary measures were obtained by the random effect model, and their results are presented using the Forest Plot graph. The qualitative synthesis was based on the description of the main factors associated with Vitamin A Deficiency. Results: we included 14 cross-sectional studies with observations in basic health units, daycare centers, and households. The summary measure indicated Vitamin A Deficiency of 20% (CI95%= 17% - 23%), with high homogeneity according to the source of the sample. Lower age of the child, low birth weight, poor iron nutritional status, diarrhea, subclinical infection, inadequate basic sanitation conditions, younger mothers and less maternal educa-tion represented the main exposures associated with the outcome. Conclusion: the results show Vitamin A Deficiency as a public health problem in Brazilian children under 5 years old, especially when related to the development of infectious processes and maternal and child characteristics that show greater susceptibility.

Coverage and educational actions related to the national vitamin A supplementation program: a study in children from the state of Alagoas

OBJECTIVES

To estimate the coverage of the National Vitamin A Supplementation Program (Programa Nacional de Suplementação de Vitamina A) in children from Alagoas, to identify factors associated with this coverage, and to analyze the adequacy of nutrition education actions.

METHODS

Household survey involving a representative probabilistic sample of children aged 6 to 59 months from Alagoas and their mothers (n=509). Coverage was defined by the percentage of children with supplementation records in the last semester. The association between the independent variables (socioeconomic, demographic, and health) and the National Vitamin A Supplementation Program coverage was analyzed based on the prevalence ratio and its 95% CI. The mothers' knowledge of questions related to vitamin A was considered as an indicator of the adequacy of nutrition education actions.

RESULTS

Program coverage was 91.9% in children aged 6-11.9 months and 38.6% in children aged 12-59 months. In the adjusted analysis, the factors that were associated with greater coverage were: age between 6-11.9 months (PR=2.50, 95% CI: 2.10-2.96), living in rural areas (PR=1.45, 95% CI: 1.20-1.76) and living in a house with ≤ 4 rooms (PR=1.33, 95% CI: 1.09-1.63). Only 26.1% of the mothers were able to mention some food source of vitamin A and only 19.2% were aware of the consequences of vitamin deficiency for health.

CONCLUSIONS

The National Vitamin A Supplementation Program coverage is below the targets set by the Ministry of Health (except for children <12 months). The factors associated with greater coverage indicate an adequate focus of the program. The nutrition education activities have not demonstrated satisfactory results. This information should guide actions to improve the program.

Vitamin A and Pregnancy: A Narrative Review

Vitamin A is a crucial micronutrient for pregnant women and their fetuses. In addition to being essential for morphological and functional development and for ocular integrity, vitamin A exerts systemic effects on several fetal organs and on the fetal skeleton. Vitamin A requirements during pregnancy are therefore greater. Vitamin A deficiency (VAD) remains the leading cause of preventable blindness in the world. VAD in pregnant women is a public health issue in most developing countries. In contrast, in some developed countries, excessive vitamin A intake during pregnancy can be a concern since, when in excess, this micronutrient may exert teratogenic effects in the first 60 days following conception. Routine prenatal vitamin A supplementation for the prevention of maternal and infant morbidity and mortality is not recommended; however, in regions where VAD is a public health issue, vitamin A supplementation is recommended to prevent night blindness. Given the importance of this topic and the lack of a complete, up-to-date review on vitamin A and pregnancy, an extensive review of the literature was conducted to identify conflicting or incomplete data on the topic as well as any gaps in existing data.

The Prevalence of Vitamin A Deficiency and Associated Factors in Pregnant Women Receiving Prenatal Care at a Reference Maternity Hospital in Northeastern Brazil

Vitamin A is essential for mother and child; however, vitamin A deficiency (VAD) remains a public health issue in various countries, affecting around 19 million pregnant women. In Brazil, the scarcity and inconsistency of data have prevented the prevalence and epidemiological status of VAD from being established. This study aimed to analyze vitamin A nutritional status in women receiving prenatal care at a reference center in northeastern Brazil. A cross-sectional study was conducted with a sample of 676 women. Serum retinol was measured by high-performance liquid chromatography. Subclinical infection was detected by measuring C-reactive protein (CRP). The World Health Organization criteria were used in the prevalence analysis, VAD classification level, and CRP effect evaluation. The prevalence of VAD (serum retinol <0.70 μmol/L) was 6.2% (95% confidence interval 4.5–8.3). In the univariate analysis, the variables significantly associated with VAD (p < 0.05) were having <12 years of schooling, being in the third trimester of pregnancy, and anemia. In the final multivariate model, the variables that remained significantly associated (p < 0.05) were being in the third trimester of pregnancy and anemia. VAD constituted a mild public health problem in this sample of pregnant women and was associated with the third trimester of pregnancy and maternal anemia.

[Nutritional and sociodemographic characteristics of nursing mothers: a systematic review]

A systematic review of nutritional and sociodemographic characteristics of nursing mothers, using the published literature from 2004 to 2014 in the Biblioteca Virtual de Saúde and Medline databases. Using the following key words, 561 articles were identified: "Human Milk" and "Milk Banks"; keywords: "Profile," "Nutritional," "Milk Donor," "Nursing Mother" and "Nursing Mothers"; available abstracts; date and language. From these, 84.1% were excluded for not dealing with the established subject, 1.8% for being a review and 7.5% for the unavailability of abstracts for study. Thirty-seven articles were selected, of which 18.9% analyzed the profile of the HM donor. Of the total, 89.2% reported age, the majority between 20 and 30 years of age. The level of schooling was mentioned in 32.4% ranging from elementary school and higher education. With respect to income, a higher prevalence of low socioeconomic status was observed. About the nutritional status, 45.9% of the studies measured the body mass index and 29.4% reported the predominance of excess weight. There were deficiencies, particularly of vitamin A, with frequencies between 9% and 26%. A majority of young adult mothers, varied schooling, low income and nutritional deficiencies were noted, demanding interventions to improve health and increase HM donations.

[Micronutrient deficiencies in Brazilian children attending daycare centers: a review of the literature]

The scope of the study was to review the scientific publications on the nutritional status of iron, vitamin A and zinc among Brazilian children attending daycare centers, focusing on diagnostic methods, the prevalence of respective deficiencies and associated factors. A review of the literature was conducted in the PubMed, LILACS and SciELO databases. Observational studies with random representative samples using biochemical indicators to evaluate the nutritional status of iron, vitamin A and zinc of children attending public daycare centers were included. The average weighted prevalence for anemia and vitamin A deficiency was estimated. The variables associated with anemia were computed. Twenty-one observational studies were included, in which the nutritional status of iron, vitamin A and zinc were analyzed in 17, 4 and 3, respectively. The average weighted prevalence of anemia and vitamin A deficiency were 42.7% and 12.5%, respectively. Young children and children living in less favorable socioeconomic situations represented the main explanatory conditions predominantly associated with the occurrence of anemia. The results suggest a high prevalence of anemia, as well as vitamin A deficiency in Brazilian children attending daycare centers, with etiological prospects focused on infectious diseases.

Vitamin A deficiency and factors associated with retinol levels in public school students

ABSTRACT Objective To estimate the prevalence of vitamin A deficiency and determine the socioeconomic and demographic factors associated with serum retinol levels in public school students. Methods This cross-sectional study included 245 students from the urban and rural areas of the city of Teresina, Piauí, Brazil. Socioeconomic data were collected using a form. Serum retinol level was determined by high-performance liquid chromatography and classified according to the cut-off points provided by the World Health Organization. All statistical tests had a significance level of 5%. Results The prevalence of vitamin A deficiency (retinol level <0.70µmol/L) was 9.8% (95%CI=7.9-10.0). The prevalences of low and acceptable retinol levels (<1.05mol/L) were higher in students aged 12-14 years living in households without piped water supply (p>0.05). Water well or other untreated water sources were the factors most strongly associated with low retinol levels (OR=3.28; 95%CI=1.48-7.28; p=0.003). Conclusion Vitamin A deficiency was characterized as a mild public health problem in the students, indicating the need of actions that address this issue in schools and of studies with larger samples to investigate the problem at the municipal and state levels. Untreated water intake, a possible source of waterborne illnesses, contributed to lower retinol levels.

Vitamin A supplementation in Brazilian pregnant and postpartum women: a systematic review

OBJECTIVE

To assess the impact of vitamin A supplementation on adult pregnant and puerperal women in Brazil regarding the content of vitamin A and secretory immunoglobulin A on colostrum and breast milk, in child's health conditions, and in mother-child binomial vitamin A status.

METHODS

A research was conducted in Medline, Scopus, Web of Science, and Lilacs electronic databases for the studies published between January 2000 and January 2014. The methodological quality of the studies was assessed according to Jadad scale. The study search was conducted in January 2014, independently by two authors.

RESULTS

Seven studies were found concerning the effects of vitamin A supplementation in the puerperal period on breast milk and infant morbidity. No study regarding pregnant women supplementation was found. The supplementation in the puerperal period raised the retinol content on breast milk, thus increasing the offer of vitamin A for the child and the concentration of secretory immunoglobulin A on colostrum. There was no description of effects on infant morbidity.

CONCLUSION

It seems that the advantages of postpartum supplementation were not established in the Brazilian program, although the supplementation contributes to a better nutritional status of vitamin A for both the child and the puerperal woman and increases the offer of vitamin A for the newborn through the breast milk.

Antioxidants Mediate Both Iron Homeostasis and Oxidative Stress

Oxidative stress is a common denominator in the pathogenesis of many chronic diseases. Therefore, antioxidants are often used to protect cells and tissues and reverse oxidative damage. It is well known that iron metabolism underlies the dynamic interplay between oxidative stress and antioxidants in many pathophysiological processes. Both iron deficiency and iron overload can affect redox state, and these conditions can be restored to physiological conditions using iron supplementation and iron chelation, respectively. Similarly, the addition of antioxidants to these treatment regimens has been suggested as a viable therapeutic approach for attenuating tissue damage induced by oxidative stress. Notably, many bioactive plant-derived compounds have been shown to regulate both iron metabolism and redox state, possibly through interactive mechanisms. This review summarizes our current understanding of these mechanisms and discusses compelling preclinical evidence that bioactive plant-derived compounds can be both safe and effective for managing both iron deficiency and iron overload conditions.

Prevalence and factors associated to vitamin A deficiency in children attending public day care centers in the Southwest of Bahia

Abstract Objectives: to determine the prevalence of vitamin A deficiency and factors associated to children attending public day care centers in the Southwest of Bahia. Methods: a cross-sectional study involving 303 children aged 24 to 60 months attending public day care centers in the city of Vitória da Conquista, BA. A questionnaire was applied for the parents or legal guardians to answer and the children's height and weight were measured. Blood samples were collected to analyze serum retinol taking in consideration the values below 0.70 imol/L as inadequate. The vaccination card was verified in relation to the adequacy of vitamin A supplementation. Food weighting was done to evaluate the consuming of lipids and vitamin A. The association between the variables and vitamin A deficiency was verified by logistic regression. Results: the prevalence of inadequate serum retinol levels was 13.1% (1.99 ± 1.17 imol/L); 4.3% were low height and 1.2% of thinness. Most children (91.7%) had their vitamin A doses outdated on their vaccination cards. The variables associated to vitamin A deficiency were children aged less or equal to 34 months (OR: 2.66, 95% CI: 1.23 - 5.74) and maternal age was less than 26 years (OR: 2.39; 95% CI: 1.11 - 5.17). Conclusions: vitamin A deficiency configures as a moderate public health problem in children attending public day care centers in the Southwest of Bahia.

[Vitamin A and D status among child participants in a food supplementation program]

Vitamin A and D serum concentrations and risk factors for their deficiencies were investigated in children participating in a government-sponsored fortified milk program. The study used multivariate linear regression analysis with hierarchical selection of independent variables: socio-demographic conditions, children's health, food consumption, breastfeeding, fortified milk, exposure to sunlight, anthropometric measurements, and serum concentration of retinol and 25(OH)D. Vitamin A and vitamin D insufficiency and deficiency values were defined as < 1.05 µmol/L, < 0.7 µmol/L, < 30 ng/mL, and < 20 ng/mL, respectively. Vitamin A and D intake was inadequate. Prevalence rates for vitamin A and vitamin D insufficiency and deficiency were 19%, 6%, 82%, and 58%, respectively. Factors associated with low serum vitamin A were exclusive breastfeeding for less than 120 days, low maternal schooling, maternal unemployment, more consumers of fortified milk in the family, and low serum vitamin D. Factors associated with vitamin D deficiency were low exposure to sunlight and low serum vitamin A. Nutritional education is needed to improve children's nutritional status.

Prevalence and factors associated with vitamin A deficiency in children and adolescents

OBJECTIVE

To identify the prevalence and factors associated with vitamin A deficiency (VAD) in children and adolescents.

METHODS

This was a cross-sectional study involving 546 schoolchildren, aged between 7 and 14 years, of both genders, enrolled in public elementary schools. Blood was collected for measurement of serum retinol. The retinol concentration in the samples was determined by high performance liquid chromatography (HPLC). Data were collected on anthropometrics, dietary, demographic, and socioeconomic factors. Polytomous logistic regression was used to evaluate the associations of interest.

RESULTS

Approximately 27.5% of the students had retinol values<30 μg/dL. The multivariate analysis showed, after the appropriate adjustments, a positive and statistically significant association of moderate/severe VAD (OR=2.19; 95% CI 1.17 to 4.10) and marginal VAD (OR=2.34; 95% CI 1.47 to 3.73) with age<10 years. There was also association of VAD moderate/severe (OR=2.01; 95% CI 1.01 to 5.05) and borderline VAD (OR=2.14; 95% CI: 1.08 to 4.21) with the anthropometric status of underweight. Lower intake of retinol was detected among those with severe VAD.

CONCLUSION

VAD is a health concern among children and adolescents. Lower weight and younger schoolchildren had greater vulnerability to VAD.

Fatores associados à hipovitaminose A em crianças menores de cinco anos

OBJETIVOS: identificar os fatores associados à hipovitaminose A em crianças da região semiárida de Alagoas. MÉTODOS: estudo transversal com amostra probabilística de 551 crianças menores de cinco anos. Os níveis séricos de retinol foram aferidos usando-se cromatografia líquida de alta eficiência. Na identificação da associação entre as variáveis independentes e hipovitaminose A (retinol <20 µg/dL) utilizou-se a razão de prevalência (RP) e respectivo IC95% calculados por regressão de Poisson com ajuste robusto da variância, tanto na análise bruta quanto na ajustada. Nesta, foram incluídas todas as variáveis que naanálise bruta atingiram p<0,1. Associações foram consideradas estatisticamente significantes quando p<0,05. RESULTADOS: a prevalência de hipovitaminose A foi de 45,4% e as variáveis que se mantiveram associadas após análise multivariável foram a baixa escolaridade materna (RP=1,66; IC95%: 1,12-2,44), obaixo peso ao nascer (RP=1,41; IC95%: 1,01-1,98) eter de 12,1 a 24 meses (RP=1,45; IC95%: 1,04-2,02). CONCLUSÕES: evidencia-se a relevância epidemiológica da hipovitaminose A em crianças do semiárido alagoano. Crianças nascidas com baixo peso, com mães de baixa escolaridade e no segundo ano de vida devem receber atenção prioritária.

Vitamin A modulates the expression of genes involved in iron bioavailability

Iron bioavailability seems to be regulated by vitamin A (VA) but the molecular events involved in this mechanism are not well understood. It is also known that retinoids mediate most of their function via interaction with retinoid receptors, which act as ligand-activated transcription factors controlling the expression of a number of target genes. Here, we evaluated the VA effects on the modulation of the levels of mRNA encoding proteins involved in the iron bioavailability, whether in the intestinal absorption process or in the liver iron metabolism. The expression of genes involved in iron intestinal absorption (divalent metal transporter 1, duodenal cytochrome B, ferroportin 1 FPN1, and ferritin) were evaluated in vitro by treating Caco-2 cells with retinoic acid or in vivo by observing the effects of vitamin A deficiency (VAD) in BALB/C mice. Liver hepcidin and ferritin mRNA levels were upregulated by VAD; however, this condition did not promote any change on the expression of those genes that participate in the iron absorption. Moreover, data from the in vitro analysis showed that VA induced FPN1 gene expression by a hepcidin-independent manner. Therefore, the in vivo results support the idea that VAD may not affect iron absorption but would rather affect iron mobilization mechanisms. On the other hand, our results using Caco-2 cells raises the possibility that VA addition to intestinal epithelium may improve iron absorption through the induction of FPN1 gene expression.

Avaliação participativa do Programa Nacional de Suplementação de Vitamina A em um município da Região Nordeste do Brasil

Esta pesquisa teve o propósito de avaliar o Programa Nacional de Suplementação de Vitamina A em um município da Região Nordeste do Brasil, com a participação de responsáveis por crianças menores de cinco anos de idade. Trata-se de um estudo transversal, de base populacional, com abordagens qualitativa e quantitativa. Foram realizadas 657 entrevistas estruturadas e análise do registro das doses de vitamina A nos cartões de vacinação das crianças. Observou-se que a população tem acesso às megadoses de vitamina A. No entanto, percebeu-se uma fragilidade no conhecimento acerca do programa e da vitamina A, especialmente entre a população de menor escolaridade. Observou-se ainda que a cobertura do programa está aquém da meta recomendada pelo Ministério da Saúde, sobretudo a partir dos 18 meses de idade. Diante do exposto, é necessário intensificar as ações educativas relacionadas ao programa, no intuito de orientar e sensibilizar os responsáveis quanto à importância da vitamina A, de sua suplementação e da ingestão de alimentos-fonte deste nutriente para a saúde da criança.