Anemia ferropriva em escolares da primeira série do ensino fundamental da rede pública de educação de uma região de Brasília, DF

Wheat flour fortification with iron and other micronutrients for reducing anaemia and improving iron status in populations

BACKGROUND

Anaemia is a condition where the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body's physiological needs. Fortification of wheat flour is deemed a useful strategy to reduce anaemia in populations.

OBJECTIVES

To determine the benefits and harms of wheat flour fortification with iron alone or with other vitamins and minerals on anaemia, iron status and health-related outcomes in populations over two years of age.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, 21 other databases and two trials registers up to 21 July 2020, together with contacting key organisations to identify additional studies.

SELECTION CRITERIA

We included cluster- or individually-randomised controlled trials (RCTs) carried out among the general population from any country, aged two years and above. The interventions were fortification of wheat flour with iron alone or in combination with other micronutrients. We included trials comparing any type of food item prepared from flour fortified with iron of any variety of wheat DATA COLLECTION AND ANALYSIS: Two review authors independently screened the search results and assessed the eligibility of studies for inclusion, extracted data from included studies and assessed risks of bias. We followed Cochrane methods in this review.

MAIN RESULTS

Our search identified 3538 records, after removing duplicates. We included 10 trials, involving 3319 participants, carried out in Bangladesh, Brazil, India, Kuwait, Philippines, South Africa and Sri Lanka. We identified two ongoing studies and one study is awaiting classification. The duration of interventions varied from 3 to 24 months. One study was carried out among adult women and one trial among both children and nonpregnant women. Most of the included trials were assessed as low or unclear risk of bias for key elements of selection, performance or reporting bias. Three trials used 41 mg to 60 mg iron/kg flour, three trials used less than 40 mg iron/kg and three trials used more than 60 mg iron/kg flour. One trial used various iron levels based on type of iron used: 80 mg/kg for electrolytic and reduced iron and 40 mg/kg for ferrous fumarate. All included studies contributed data for the meta-analyses. Iron-fortified wheat flour with or without other micronutrients added versus wheat flour (no added iron) with the same other micronutrients added Iron-fortified wheat flour with or without other micronutrients added versus wheat flour (no added iron) with the same other micronutrients added may reduce by 27% the risk of anaemia in populations (risk ratio (RR) 0.73, 95% confidence interval (CI) 0.55 to 0.97; 5 studies, 2315 participants; low-certainty evidence). It is uncertain whether iron-fortified wheat flour with or without other micronutrients reduces iron deficiency (RR 0.46, 95% CI 0.20 to 1.04; 3 studies, 748 participants; very low-certainty evidence) or increases haemoglobin concentrations (in g/L) (mean difference MD 2.75, 95% CI 0.71 to 4.80; 8 studies, 2831 participants; very low-certainty evidence). No trials reported data on adverse effects in children (including constipation, nausea, vomiting, heartburn or diarrhoea), except for risk of infection or inflammation at the individual level. The intervention probably makes little or no difference to the risk of Infection or inflammation at individual level as measured by C-reactive protein (CRP) (mean difference (MD) 0.04, 95% CI -0.02 to 0.11; 2 studies, 558 participants; moderate-certainty evidence). Iron-fortified wheat flour with other micronutrients added versus unfortified wheat flour (nil micronutrients added) It is unclear whether wheat flour fortified with iron, in combination with other micronutrients decreases anaemia (RR 0.77, 95% CI 0.41 to 1.46; 2 studies, 317 participants; very low-certainty evidence). The intervention probably reduces the risk of iron deficiency (RR 0.73, 95% CI 0.54 to 0.99; 3 studies, 382 participants; moderate-certainty evidence) and it is unclear whether it increases average haemoglobin concentrations (MD 2.53, 95% CI -0.39 to 5.45; 4 studies, 532 participants; very low-certainty evidence). No trials reported data on adverse effects in children. Nine out of 10 trials reported sources of funding, with most having multiple sources. Funding source does not appear to have distorted the results in any of the assessed trials.

AUTHORS' CONCLUSIONS

Fortification of wheat flour with iron (in comparison to unfortified flour, or where both groups received the same other micronutrients) may reduce anaemia in the general population above two years of age, but its effects on other outcomes are uncertain. Iron-fortified wheat flour in combination with other micronutrients, in comparison with unfortified flour, probably reduces iron deficiency, but its effects on other outcomes are uncertain. None of the included trials reported data on adverse side effects except for risk of infection or inflammation at the individual level. The effects of this intervention on other health outcomes are unclear. Future studies at low risk of bias should aim to measure all important outcomes, and to further investigate which variants of fortification, including the role of other micronutrients as well as types of iron fortification, are more effective, and for whom.

Wheat flour fortification with iron for reducing anaemia and improving iron status in populations

BACKGROUND

Anaemia is a condition where the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body's physiologic needs. Fortification of wheat flour is deemed a useful strategy to reduce anaemia in populations.

OBJECTIVES

To determine the benefits and harms of wheat flour fortification with iron alone or with other vitamins and minerals on anaemia, iron status and health-related outcomes in populations over two years of age.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and other databases up to 4 September 2019.

SELECTION CRITERIA

We included cluster- or individually randomised controlled trials (RCT) carried out among the general population from any country aged two years and above. The interventions were fortification of wheat flour with iron alone or in combination with other micronutrients. Trials comparing any type of food item prepared from flour fortified with iron of any variety of wheat were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results and assessed the eligibility of studies for inclusion, extracted data from included studies and assessed risk of bias. We followed Cochrane methods in this review.

MAIN RESULTS

Our search identified 3048 records, after removing duplicates. We included nine trials, involving 3166 participants, carried out in Bangladesh, Brazil, India, Kuwait, Phillipines, Sri Lanka and South Africa. The duration of interventions varied from 3 to 24 months. One study was carried out among adult women and one trial among both children and nonpregnant women. Most of the included trials were assessed as low or unclear risk of bias for key elements of selection, performance or reporting bias. Three trials used 41 mg to 60 mg iron/kg flour, two trials used less than 40 mg iron/kg and three trials used more than 60 mg iron/kg flour. One trial employed various iron levels based on type of iron used: 80 mg/kg for electrolytic and reduced iron and 40 mg/kg for ferrous fumarate. All included studies contributed data for the meta-analyses. Seven studies compared wheat flour fortified with iron alone versus unfortified wheat flour, three studies compared wheat flour fortified with iron in combination with other micronutrients versus unfortified wheat flour and two studies compared wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with the same micronutrients (but not iron). No studies included a 'no intervention' comparison arm. None of the included trials reported any other adverse side effects (including constipation, nausea, vomiting, heartburn or diarrhoea). Wheat flour fortified with iron alone versus unfortified wheat flour (no micronutrients added) Wheat flour fortification with iron alone may have little or no effect on anaemia (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.61 to 1.07; 5 studies; 2200 participants; low-certainty evidence). It probably makes little or no difference on iron deficiency (RR 0.43, 95% CI 0.17 to 1.07; 3 studies; 633 participants; moderate-certainty evidence) and we are uncertain about whether wheat flour fortified with iron increases haemoglobin concentrations by an average 3.30 (g/L) (95% CI 0.86 to 5.74; 7 studies; 2355 participants; very low-certainty evidence). No trials reported data on adverse effects in children, except for risk of infection or inflammation at the individual level. The intervention probably makes little or no difference to risk of Infection or inflammation at individual level as measured by C-reactive protein (CRP) (moderate-certainty evidence). Wheat flour fortified with iron in combination with other micronutrients versus unfortified wheat flour (no micronutrients added) Wheat flour fortified with iron, in combination with other micronutrients, may or may not decrease anaemia (RR 0.95, 95% CI 0.69 to 1.31; 2 studies; 322 participants; low-certainty evidence). It makes little or no difference to average risk of iron deficiency (RR 0.74, 95% CI 0.54 to 1.00; 3 studies; 387 participants; moderate-certainty evidence) and may or may not increase average haemoglobin concentrations (mean difference (MD) 3.29, 95% CI -0.78 to 7.36; 3 studies; 384 participants; low-certainty evidence). No trials reported data on adverse effects in children. Wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with same micronutrients (but not iron) Given the very low certainty of the evidence, the review authors are uncertain about the effects of wheat flour fortified with iron in combination with other micronutrients versus fortified wheat flour with same micronutrients (but not iron) in reducing anaemia (RR 0.24, 95% CI 0.08 to 0.71; 1 study; 127 participants; very low-certainty evidence) and in reducing iron deficiency (RR 0.42, 95% CI 0.18 to 0.97; 1 study; 127 participants; very low-certainty evidence). The intervention may make little or no difference to the average haemoglobin concentration (MD 0.81, 95% CI -1.28 to 2.89; 2 studies; 488 participants; low-certainty evidence). No trials reported data on the adverse effects in children. Eight out of nine trials reported source of funding with most having multiple sources. Funding source does not appear to have distorted the results in any of the assessed trials.

AUTHORS' CONCLUSIONS

Eating food items containing wheat flour fortified with iron alone may have little or no effect on anaemia and probably makes little or no difference in iron deficiency. We are uncertain on whether the intervention with wheat flour fortified with iron increases haemoglobin concentrations improve blood haemoglobin concentrations. Consuming food items prepared from wheat flour fortified with iron, in combination with other micronutrients, has little or no effect on anaemia, makes little or no difference to iron deficiency and may or may not improve haemoglobin concentrations. In comparison to fortified flour with micronutrients but no iron, wheat flour fortified with iron with other micronutrients, the effects on anaemia and iron deficiency are uncertain as certainty of the evidence has been assessed as very low. The intervention may make little or no difference to the average haemoglobin concentrations in the population. None of the included trials reported any other adverse side effects. The effects of this intervention on other health outcomes are unclear.

Fortification of maize flour with iron for controlling anaemia and iron deficiency in populations

BACKGROUND

Approximately 800 million women and children have anaemia, a condition thought to cause almost 9% of the global burden of years lived with disability. Around half this burden could be amenable to interventions that involve the provision of iron. Maize (corn) is one of the world's most important cereal grains and is cultivated across most of the globe. Several programmes around the world have fortified maize flour and other maize-derived foodstuffs with iron and other vitamins and minerals to combat anaemia and iron deficiency.

OBJECTIVES

To assess the effects of iron fortification of maize flour, corn meal and fortified maize flour products for anaemia and iron status in the general population.

SEARCH METHODS

We searched the following international and regional sources in December 2017 and January 2018: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; MEDLINE (R) In Process; Embase; Web of Science (both the Social Science Citation Index and the Science Citation Index); CINAHL Ebsco; POPLINE; AGRICOLA (agricola.nal.usda.gov); BIOSIS (ISI); Bibliomap and TRoPHI; IBECS; Scielo; Global Index Medicus - AFRO (includes African Index Medicus); EMRO (includes Index Medicus for the Eastern Mediterranean Region); LILACS; PAHO (Pan American Health Library); WHOLIS (WHO Library); WPRO (includes Western Pacific Region Index Medicus); IMSEAR, Index Medicus for the South-East Asian Region; IndMED, Indian medical journals; and the Native Health Research Database. We searched clinicaltrials.gov and the International Clinical Trials Registry Platform (ICTRP) for any ongoing or planned studies on 17 January 2018 and contacted authors of such studies to obtain further information or eligible data if available.For assistance in identifying ongoing or unpublished studies, we also contacted relevant international organisations and agencies working in food fortification on 9 August 2016.

SELECTION CRITERIA

We included cluster- or individually randomised controlled trials and observational studies. Interventions included (central/industrial) fortification of maize flour or corn meal with iron alone or with other vitamins and minerals and provided to individuals over 2 years of age (including pregnant and lactating women) from any country.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of studies for inclusion, extracted data from included studies and assessed the risk of bias of the included studies. Trial designs with a comparison group were included to assess the effects of interventions. Trial designs without a control or comparison group (uncontrolled before-and-after studies) were included for completeness but were not considered in assessments of the overall effectiveness of interventions or used to draw conclusions regarding the effects of interventions in the review.

MAIN RESULTS

Our search yielded 4529 records. After initial screening of titles and abstracts, we reviewed the full text of 75 studies (80 records). We included 5 studies and excluded 70. All the included studies assessed the effects of providing maize products fortified with iron plus other vitamins and minerals versus unfortified maize flour. No studies compared this intervention to no intervention or looked at the relative effect of flour and products fortified with iron alone (without other vitamins and minerals). Three were randomised trials involving 2610 participants, and two were uncontrolled before-and-after studies involving 849 participants.Only three studies contributed data for the meta-analysis and included children aged 2 to 11.9 years and women. Compared to unfortified maize flour, it is uncertain whether fortifying maize flour or corn meal with iron and other vitamins and minerals has any effect on anaemia (risk ratio (RR) 0.90, 95% confidence interval (CI) 0.58 to 1.40; 2 studies; 1027 participants; very low-certainty evidence), or on the risk of iron deficiency (RR 0.75, 95% CI 0.49 to 1.15; 2 studies; 1102 participants; very low-certainty evidence), haemoglobin concentration (mean difference (MD) 1.25 g/L, 95% CI -2.36 to 4.86 g/L; 3 studies; 1144 participants; very low-certainty evidence) or ferritin concentrations (MD 0.48 µg/L, 95% CI -0.37 to 1.33 µg/L; 1 study; 584 participants; very low-certainty evidence).None of the studies reported on any adverse effects. We judged the certainty of the evidence to be very low based on GRADE, so we are uncertain whether the results reflect the true effect of the intervention. We downgraded evidence due to high risk of selection bias and unclear risk of performance bias in one of two included studies, high heterogeneity and wide CIs crossing the line of no effect for anaemia prevalence and haemoglobin concentration.

AUTHORS' CONCLUSIONS

It is uncertain whether fortifying maize flour with iron and other vitamins and minerals reduces the risk of anaemia or iron deficiency in children aged over 2 years or in adults. Moreover, the evidence is too uncertain to conclude whether iron-fortified maize flour, corn meal or fortified maize flour products have any effect on reducing the risk of anaemia or on improving haemoglobin concentration in the population.We are uncertain whether fortification of maize flour with iron reduces anaemia among the general population, as the certainty of the evidence is very low. No studies reported on any adverse effects.Public organisations funded three of the five included studies, while the private sector gave grants to universities to perform the other two. The presence of industry funding for some of these trials did not appear to positively influence results from these studies.The reduced number of studies, including only two age groups (children and women of reproductive age), as well as the limited number of comparisons (only one out of the four planned) constitute the main limitations of this review.

Prevalence of anemia in schools of the metropolitan region of Curitiba, Brazil

Background

Anemia during childhood is one of the biggest public health problems worldwide, including Brazil. Insufficient or abnormal production of hemoglobin, loss of iron and excessive destruction of red blood cells are the most common causes of anemia. Among the reasons of anemia, iron deficiency accounts for 50% of anemia cases in developing countries. Affected individuals present a wide range of clinical problems, including delayed neuropsychomotor progression, impaired cellular immunity and reduction of intellectual capacity. This study aimed to evaluate the prevalence of anemia in children attending public schools in the metropolitan region of Curitiba, Paraná, Brazil.

Method

A retrospective study was conducted of 409 children aged 8–12 years old included in an extension project of the Universidade Federal do Paraná. The results of complete blood count and hemoglobin electrophoresis of all children were evaluated. Anemia was considered when the hemoglobin levels were <11.5 g/dL.

Results

The prevalence of anemia was found to be 2.2% of the population studied, with hypochromic microcytic anemia being the most common type. Seven children had sickle cell trait and one had β-thalassemia.

Conclusion

The prevalence of anemia in this study was considered normal according the World Health Organization classification, which is different from the data found in other Brazilian regions.

RISCO DE ANEMIA FERROPRIVA EM CRIANÇAS COM BAIXOS NÍVEIS DE FERRITINA

Em crianças pré-escolares a anemia ferropriva pode comprometer a capacidade de aprendizagem, além de produzir efeitos comportamentais como a falta de atenção, fadiga e cansaço que podem levar ao baixo rendimento escolar. O objetivo deste estudo foi verificar o número de crianças de 02 a 06 anos que realizaram as dosagens de ferritina, ferro sérico e hemograma, com suspeita de anemia ferropriva, num laboratório clínico, no primeiro semestre de 2011, buscando avaliar os resultados dos referidos exames e estabelecer a prevalência de anemia ferropriva nos indivíduos estudados. Foi conduzido um estudo observacional descritivo do tipo transversal. Através do software SADIG-BI, utilizado para gerenciamento de dados, foram selecionadas 363 crianças de 02 a 06 anos que realizaram os exames ferritina, ferro sérico e hemograma no período de 01/01/2011 a 31/07/2011. As crianças do sexo masculino apresentaram níveis plasmáticos de ferritina significativamente mais baixos quando comparadas com as crianças do sexo feminino (p<0,05). Com relação aos parâmetros ferro sérico e hemoglobina, não foram observadas diferenças significativas entre os participantes dos dois sexos. Das 363 crianças estudadas, 9 (2,5%) apresentavam anemia ferropriva (Hb ≤11,0 g/dL e Ferritina ≤12 ng/mL). Foi observada uma baixa prevalência de anemia ferropriva nas crianças estudadas. O achado mais importante deste estudo foi o risco quase cinco vezes maior do desenvolvimento de anemia ferropriva em crianças que apresentaram níveis plasmáticos de ferritina menores ou iguais a 12 ng/mL, sugerindo que este valor pode ser considerado o melhor ponto de corte para a população estudada.

Anemia em alunos de escolas públicas no Recife: um estudo de tendências temporais

O objetivo deste estudo foi avaliar as tendências de evolução temporal da anemia em alunos de 7 a 11 anos no bairro da Várzea (Recife-PE) com base em três inquéritos realizados em 1982, 2001 e 2005. A avaliação foi efetuada em dez escolas públicas no 1° estudo e nove nos dois últimos (uma foi desativada), em amostra de 305 alunos (1982), 684 alunos (2001) e 756 alunos (2005). A hemoglobina foi determinada em amostras de sangue colhidas por venopunção, considerando dois critérios para discriminar a anemia: pontos de corte < 12 g/dL e < 11,5 g/dL. Pelo primeiro critério, a prevalência de anemia elevou-se de 8,8% em 1982 para 18,9% em 2001, decaindo para 13,4% em 2005. Pelo segundo critério, a ocorrência de anemia decresceu de 10,7% para 3,6%, entre 2001 e 2005. Na última avaliação, o problema da anemia praticamente desapareceu, a partir dos 9 anos de idade. A evolução da anemia apresentou duas tendências bem diferenciadas: elevação num primeiro momento (1982 - 2001) e rápida diminuição numa segunda etapa (2001-2005).

Deficiência de ferro, prevalência de anemia e fatores associados em crianças de creches públicas do oeste do Paraná, Brasil

OBJETIVO: Avaliar o estado nutricional de ferro, a prevalência de anemia e fatores associados, em crianças de 6 a 24 meses frequentadoras de creche pública em Cascavel, Região Oeste do Paraná, Brasil. MÉTODOS: O estudo transversal foi realizado com amostra aleatória de 256 crianças. A coleta de dados (questionário, medidas antropométricas e amostras de sangue) ocorreu de julho a setembro de 2007. A deficiência de ferro foi avaliada em termos de transferrina, hemoglobina, volume corpuscular médio, ferro sérico e eosinófilos. Na análise estatística dos dados foram obtidas as odds ratio bruta e ajustada (regressão logística), bem como os respectivos níveis de significância (p-valor). Para identificar diferenças significativas entre as medidas quantitativas, adotou-se a Análise de Variância e o teste de comparação múltipla de Tukey. RESULTADOS: A prevalência da anemia foi de 29,7%, sendo que 77,3% das amostras apresentaram baixa concentração de ferro. A antropometria não apontou deficiência de macronutrientes, porém mostrou obesidade acima dos índices médios. Os fatores associados à anemia e à deficiência de ferro foram: doenças frequentes na família (OR=10,02), condições de moradia (OR=5,05), tempo de creche (OR=3,05), número de moradores na residência (OR=2,83) e falta de saneamento (OR=2,20). CONCLUSÃO: A prevalência de anemia e a elevada deficiência de ferro detectada evidenciam um grave problema de saúde pública entre os pré-escolares do município de Cascavel, Paraná. Apesar da amplitude do problema, a anemia não está sendo reconhecida, prevenida e tratada adequadamente. Neste estudo são sugeridas algumas possíveis intervenções.

Fatores associados à anemia em crianças e adolescentes de escolas públicas de Salvador, Bahia, Brasil

Trata-se de um estudo para avaliar os fatores associados à anemia. Participaram deste estudo 1.013 indivíduos com idade entre 7 e 14 anos, matriculados na rede pública de ensino em Salvador, Bahia, Brasil. Os participantes foram submetidos a exame de sangue para dosagem de hemoglobina, exame antropométrico e obtiveram-se informações sobre consumo alimentar e condições sócio-econômicas, domiciliares e ambientais da família, além do cuidado materno dispensado à criança. Foi detectada uma prevalência de 24,5% de anêmicos entre os participantes, com valor médio dos níveis de hemoglobina de 12,68g/dL, concentração mínima de 7,7g/dL e máxima de 16,8g/dL. A anemia foi significativamente associada à inadequação crescente de consumo de ferro biodisponível (ORadequação entre 50% a 99,9% = 1,57; IC95%: 1,07-2,29;p = 0,020 e ORadequação < 50% = 1,68; IC95%: 1,10-2,56; p = 0,016) e à renda familiar menor do que 1 salário mínimo (OR = 1,42; IC95%: 1,03-1,96; p = 0,035). A prevalência de anemia em crianças e adolescentes é elevada, especialmente em indivíduos mais pobres e com baixo consumo de ferro biodisponível.

Concentrações de hemoglobina e ferritina sérica em escolares da rede pública municipal de Teresina, Piauí, Nordeste do Brasil

OBJETIVOS: avaliar o estado nutricional de ferro em escolares de instituições públicas de ensino de Teresina, Piauí, Brasil. MÉTODOS: corte transversal, envolvendo amostra aleatória, selecionada em duas etapas, de 747 escolares (7-11 anos), de ambos os sexos, no período de agosto / setembro de 2000. A anemia foi rastreada em 747 escolares e para o diagnóstico adotou-se a concentração de hemoglobina (Hb) <11,5g/dL. As reservas corporais de ferro foram estimadas em 207 escolares, mediante análise das concentrações de ferritina sérica (FerS), considerando-se baixas reservas valores <15 µg/L. RESULTADOS: a prevalência de concentrações inadequadas de Hb (< 11,5g/dL) foi de 14,3% (IC95% 12,2-17,4) e de reservas inadequadas de ferro (FerS< 15,0µg/L) de 20,3% (IC95% 15,2-26,6). A prevalência de anemia foi semelhante entre os sexos (p=0,60) e as faixas etárias (p=0,85). Comportamento distributivo similar foi observado no que diz respeito às reservas inadequadas de ferro, frentes às variáveis sexo (p=0,19) e idade (p=0,24). As concentrações de FerS não mostraram correlação (r=0,1; p=0,168) com as de Hb. A prevalência de anemia ferropênica (Hb< 11,5 g/dL e FerS< 15,0 µg/L) foi de 26,3% (IC95% 17,3-37,5). CONCLUSÕES: em Teresina, a deficiência de ferro e a anemia em escolares devem ser consideradas como um problema de saúde pública que requer efetivo programa de prevenção e controle. No entanto, a anemia parece não ser explicada apenas pela deficiência de ferro; outros fatores etiológicos devem, portanto, ser considerados, a exemplo da deficiência de outros micronutrientes, infecções/infestações parasitárias, distúrbios hereditários e exposição a poluentes ambientais.