Prevalence of anaemia in Brazilian children in different epidemiological scenarios: an updated meta-analysis

Hidden hunger - a narrative review

OBJECTIVE

Malnutrition is characterized by situations of undernutrition and obesity resulting from the lack of micronutrients with the greatest impact on children. The objective of this review was to highlight inadequate food consumption, food security, and nutritional inadequacy leading to hidden hunger and the prevention and treatment of the main micronutrient deficiencies in Brazil.

DATA SOURCE

Literature review carried out through a bibliographic survey in PubMed (National Library of Medicine, United States), Lilacs (Latin American and Caribbean Literature in Health Sciences), and SciELO (Scientific Electronic Library Online) databases. The search used the terms Occult hunger, (hidden hunger), and Child, in articles published between 2013 and 2023 in Portuguese, English and Spanish. The search was performed on 06/25/2023.

DATA SYNTHESIS

The lack of micronutrients can occur insidiously and without clinical manifestations, being called hidden hunger. The prevention of nutritional deficiencies is part of the recommended actions in childcare, with healthy eating. Studies were cited related to macro and micronutrient intake deficiencies, both national and international, and strategies to improve micronutrient intake, including routine supplementation of iron, and vitamins D and A. The diagnosis, prevention, and treatment of the main deficiencies in Brazil (iron, vitamin A, vitamin D, zinc), currently adopted, concluded the topic.

CONCLUSION

Zero hunger and zero obesity must be part of the same policy, together with a nutritional education program.

Prevalence and correlates of childhood anemia in the MINA-Brazil birth cohort study

OBJECTIVE

This study aimed to describe the prevalence and predictors of childhood anemia in an Amazonian population-based birth cohort study.

METHODS

Prevalence of maternal anemia was estimated at delivery (hemoglobin [Hb] concentration < 110 g/L) in women participating in the MINA-Brazil birth cohort study and in their children, examined at ages one, two (Hb < 110 g/L), and five (Hb < 115 g/L). Moreover, ferritin, soluble transferrin receptor, and C-reactive protein concentrations were measured in mothers at delivery and in their 1- and 2-year-old children to estimate the prevalence of iron deficiency and its contribution to anemia, while adjusting for potential confounders by multiple Poisson regression analysis (adjusted relative risk [RRa]).

RESULTS

The prevalence 95% confidence interval (CI) of maternal anemia, iron deficiency, and iron-deficiency anemia at delivery were 17.3% (14.0-21.0%), 42.6% (38.0-47.2%), and 8.7% (6.3-11.6)%, respectively (n = 462). At one year of age (n = 646), 42.2% (38.7-45.8%) of the study children were anemic, 38.4% (34.6-42.3%) were iron-deficient, and 26.3 (23.0-29.9) had iron-deficiency anemia. At two years of age (n = 761), these values decreased to 12.8% (10.6-15.2%), 18.1% (15.5-21.1%), and 4.1% (2.8-5.7%), respectively; at five years of age (n = 655), 5.2% (3.6-7.2%) were anemic. Iron deficiency (RRa = 2.19; 95%CI: 1.84-2.60) and consumption of ultra-processed foods (UPF) (RRa = 1.56; 95%CI: 1.14-2.13) were significant contributors to anemia at 1 year, after adjusting for maternal schooling. At 2 years, anemia was significantly associated with maternal anemia at delivery (RRa: 1.67; 95%CI: 1.17-2.39), malaria since birth (2.25; 1.30-3.87), and iron deficiency (2.15; 1.47-3.15), after adjusting for children's age and household wealth index.

CONCLUSIONS

Anemia continues to be highly prevalent during pregnancy and early childhood in the Amazon. Public health policies should address iron deficiency, UPF intake, maternal anemia, and malaria to prevent and treat anemia in Amazonian children.

Low bioavailability of dietary iron among Brazilian children: Study in a representative sample from the Northeast, Southeast, and South regions

Background

Despite all efforts, iron deficiency anemia remains a serious public health problem among Brazilian children.

Objective

To evaluate dietary iron intake and dietary practices that interfere with the absorption of this nutrient from three regions of Brazil.

Methods

Brazil Kids Nutrition and Health Study is a cross-sectional dietary intake study in children aged 4-13.9 years old designed to investigate nutrient intakes and gaps of Brazilian children in a representative sample of households from Northeast, Southeast and South regions. Nutrient intake was assessed based on multiple-pass 24-h dietary recall and U.S. National Cancer Institute method was used to estimate usual micronutrients intakes and compliance with Dietary Reference Intakes.

Results

Five hundred sixteen individuals participated in the study (52.3% male). The top three most consumed food sources of iron were products of plant origin. Food sources of animal origin contributed with <20% of the total iron intake. Vitamin C intake was adequate, but the concomitant consumption of food sources of vitamin C with plant food sources of iron was not common. On the other hand, the concomitant intake of plant food sources of iron with food sources of iron chelators (e.g., coffee and teas) was frequent.

Conclusions

Adequate iron intake was observed in all three regions in Brazil. Children's diet showed low iron bioavailability and insufficient consumption of food sources of iron absorption stimulants. Frequent presence of iron chelators and inhibitors of iron absorption might help to explain the high prevalence of iron deficiency in the country.

Iron deficiency anemia in infants in Sousa (PB), Brazil: an association with nutritional status

OBJECTIVE

The aim of this study was to describe the prevalence of anemia and iron deficiency anemia (IDA) in infants and verify the association of iron deficiency with nutritional status.

METHODS

This cross-sectional and observational study included 104 infants aged between 7 and 9 months, assisted from August to September 2021 by the Family Health Strategy program in Sousa municipality (Paraíba, Brazil). Clinical and anthropometric data were collected, and a 24-h food recall questionnaire was applied using the DietPro software (version 5.0) in order to verify food consumption and assess iron intake. Variables associated with iron deficiency (p<0.05) were analyzed using multiple logistic regression.

RESULTS

Anemia and IDA were observed in 40.4% and 19.2% of infants, respectively. Only one infant was taking prophylactic supplementation (ferrous sulfate). Infants with IDA presented reduced hemoglobin (p<0.001) and ferritin (p<0.001) and increased Z-scores of body mass index-for-age (Z-BMI) (p=0.027), weight-for-height (p=0.007), and weight-for-age (p=0.032). All Z-scores were inversely correlated with ferritin (Z-BMI [rho: -0.37; p<0.001], weight-for-height [rho: -0.37; p<0.001], and weight-for-age [rho: -0.29; p=0.002]). Ferritin was also directly correlated with daily iron intake (rho: 0.22; p=0.018). Finally, multiple logistic regression showed a significant and direct association of iron deficiency with weight-for-height Z-score (odds ratio: 2.86; 95% confidence interval: 1.38-5.64; p=0.004).

CONCLUSION

About 60% of infants presented anemia or IDA. Iron deficiency was associated with the weight-for-height Z-score, showing the vulnerability of infants during the introduction of complementary feeding.

Exposição ao mercúrio e anemia em crianças e adolescentes de seis comunidades da Amazônia Brasileira

Resumo O mercúrio (Hg) é uma substância tóxica, sendo o consumo de pescados uma das principais fontes de exposição da população. Este artigo visa avaliar a associação entre anemia e exposição ao Hg na população infanto-juvenil de seis comunidades ribeirinhas da Amazônia Brasileira. Realizou-se a análise secundária de dados de estudos seccionais, incluindo 1.318 indivíduos, divididos em dois grupos segundo a influência do garimpo (grupo A sob influência, e grupo B sem influência). Métodos de análise multivariada foram realizados para verificar a associação entre variável de exposição (Hg no cabelo) e anemia, estratificando pelos grupos. Foram observados 348 casos de anemia (27,1%), sendo 206 entre o grupo B e 142 no grupo A. Houve diferença na mediana dos níveis de Hg entre os grupos (A = 12,8µg/g e B = 4,3µg/g, p = 0,01). Foi observada associação entre Hg no cabelo ≥ 6,0µg/g e anemia (OR = 1,38; IC95% = 1,02-1,87), fato que foi magnificado para o grupo A quando realizada estratificação (OR = 2,23; IC95% = 1,28-3,90). O estudo mostrou elevados níveis de Hg, principalmente no grupo A, e que essa substância pode ser um possível fator de risco para anemia. Além disso, as áreas geográficas pareceram modificar esse efeito, apontando para influência de outros fatores, fato que deve ser melhor avaliado.

Wildmeat consumption and child health in Amazonia

Consuming wildmeat may protect against iron-deficiency anemia, a serious public health problem globally. Contributing to debates on the linkages between wildmeat and the health of forest-proximate people, we investigate whether wildmeat consumption is associated with hemoglobin concentration in rural and urban children (< 5 years old) in central Brazilian Amazonia. Because dietary practices mediate the potential nutritional benefits of wildmeat, we also examined whether its introduction into children's diets is influenced by rural/urban location or household socio-economic characteristics. Sampling 610 children, we found that wildmeat consumption is associated with higher hemoglobin concentration among the rural children most vulnerable to poverty, but not in the least vulnerable rural, or urban children. Rural caregivers share wildmeat with children earlier-in-life than urban caregivers, potentially because of cultural differences, lower access to domesticated meat, and higher wildmeat consumption by rural households (four times the urban average). If wildmeat becomes unavailable through stricter regulations or over-harvesting, we predict a ~ 10% increased prevalence of anemia among extremely poor rural children. This modest protective effect indicates that ensuring wildmeat access is, alone, insufficient to control anemia. Sustainable wildlife management could enhance the nutritional benefits of wildlife for vulnerable Amazonians, but reducing multidimensional poverty and improving access to quality healthcare are paramount.

Prevalence of iron deficiency anemia in Brazilian women of childbearing age: a systematic review with meta-analysis

BACKGROUND

Iron deficiency anemia (IDA) is among the most common micronutrient deficiencies in women of childbearing age and may affect children's development. Brazil has several national programs to tackle this condition, such as food fortification and supplementation for pregnant women, but IDA prevalence in this population has not been systematically reviewed. We sought to determine the prevalence of IDA in Brazilian women of childbearing age through a systematic review with metanalysis.

METHODOLOGY

A protocol was previously published on the PROSPERO platform under the code CRD42020200960. A panel of the National Council for Scientific and Technological Development (CNPq) approved the protocol of this study under the public call number 26/2019. The main databases searched were MEDLINE, Web of Science, Scopus, Lilacs, and SciELO. In gray literature, the Brazilian Digital Library of Theses and Dissertations and the annals of the Brazilian Congress of Epidemiology and the Brazilian Congress of Public Health were accessed. The search strategy involved terms related to the condition (IDA) and the age group of the population of interest (teenagers and adults). Studies that had assessed the prevalence of IDA in Brazilian women of childbearing age (10-49 years) were included. Three independent reviewers read all titles and abstracts and extracted data from the included studies. Random effects meta-analyses using the Freeman-Tukey arcsine transformation were carried out with prevalence data, and meta-regression was conducted to test for subgroup differences. The quality of the studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

From 21,210 unique records screened, 237 full-texts were retrieved, of which 91 were included in the qualitative synthesis, and 83 were included in the meta-analysis. The overall IDA prevalence was 25% (95% CI [23-28], 83 studies). The subgroup of studies that used random sampling showed a prevalence of 22% (95% CI [17-27], 22 studies), whereas in those with non-random sampling, the prevalence was 27% (95% CI [23-30], 61 studies), without significant differences between subgroups in the metaregression (P = 0.13). High prevalence of IDA were found in the subgroups of studies conducted in the North and Northeast regions (30%; 95% CI [24-37]; seven studies, and 30%; 95% CI [26-34]; 27 studies, respectively), in studies conducted with indigenous population (53%; 95% CI [27-78], four studies), and with studies that had their collections after 2015 (28%; 95% CI [23-34], nine studies).

CONCLUSIONS

IDA in women of childbearing age remains a public health problem in Brazil, especially in the North and Northeast region. The national programs should be strengthened and more thoroughly supervised to decrease this condition nationally.

Prevalence of childhood anaemia in Brazil: still a serious health problem: a systematic review and meta-analysis

OBJECTIVE

To estimate the prevalence of anaemia in Brazilian children up to 83·9 months old.

DESIGN

Systematic review and meta-analysis, using databases PubMed, Scopus, SciELO, Lilacs, Google Scholar, Periódicos Capes, Arca, Biblioteca Virtual em Saúde, Microsoft Academic Search and Cochrane Library using search terms: anaemia, prevalence, child and Brazil. PROSPERO Registration number: CRD42020208818.

SETTING

Cross-sectional, cohort, case-control and intervention studies published between 2007 and 2020 were searched, excluding those who assessed children with an illness or chronic condition. The main outcome was anaemia prevalence. Random effects models based on the inverse variance method were used to estimate pooled prevalence measures. Sensitivity analyses removed studies with high contribution to overall heterogeneity.

PARTICIPANTS

From 6790 first screened, 134 eligible studies were included, totalling 46 978 children aged zero to 83·9 months analysed, with adequate regions representativeness.

RESULTS

Pooled prevalence of anaemia was 33 % (95 % CI 30, 35). Sensitivity analyses showed that withdrawal of studies that contributed to high heterogeneity did not influence national average prevalence.

CONCLUSIONS

Childhood anaemia is still a serious public health problem in Brazil, exposing 33 % of Brazilian children to the anaemia repercussions. The main limitation of the study is the estimation of national prevalence based on local surveys, but a large number of studies were included, with representation in all regions of the country, giving strength to the results. In Brazil, more public policies are needed to promote supplementation, fortification and access to healthy eating to reduce the high level of anaemia among children.

Association of Iron Supplementation Programs with Iron-Deficiency Anemia Outcomes among Children in Brazil

Anemia remains a condition with high prevalence in populations worldwide, and the prevalence of anemia among children under five years old in Brazil is approximately 40%, being higher in communities marked by social inequities. Diverse government programs during recent decades targeted iron-deficiency anemia, considering its impacts throughout the lifetime. The objective of this study was to investigate the effects of two government iron supplementation programs on health outcomes related to iron-deficiency anemia among children up to 4 years old in Brazilian municipalities. A longitudinal panel encompassing data from 5570 municipalities from 1998 to 2019 was investigated using a difference-in-differences framework with multiple interventions and distinct times of adhesion, and fixed-effects models were estimated to control for invariant municipal characteristics throughout the period in order to ensure comparability. The results indicate significant effects of the federal programs in reducing hospitalizations and lengths of stay due to iron-deficiency anemia, especially in non-poor municipalities. There was complementarity in the effects of the programs; however, neither of the programs influenced mortality rates. Thus, it is important to consider possible improvements in the operationalization of the programs, in order to achieve better results in the reduction of severe iron-deficiency anemia among children up to 4 years old.