ABSTRACT

Objective:

To analyze the temporal evolution of anemia in children aged six to 59 months in Pernambuco, based on population surveys from 1997, 2006, and 2016 and the factors associated with the situation in 2016.

Methods:

The field studies took place in the participants’ households, in the Recife Metropolitan Area, as well as in the urban and rural inland. The trend study of anemia in children used data from the State Health and Nutrition Survey (Pesquisa Estadual de Saúde e Nutrição — PESN) II (40.9%) and III (32.8%). Data from PESN IV were collected using questionnaires administered to families to verify socioeconomic and individual conditions, as well as anthropometric — weight and height — and biochemical — hemoglobin — records. We adopted the test for trend in proportion for the time trend study and Poisson regression for hypothesis tests for the associated factors. Statistically significance was set at a p-value<0.05.

Results:

In 2016, the prevalence of anemia was 24.2%, indicating a significant reduction in disease incidence. In children aged 6–23 months, this number decreased from PENS II and III to PENS IV — 63 and 55.6 to 37.7% (p<0.001), respectively. In 2016, the statistically significant variables for anemia in children were maternal hemoglobin, child's age, current or recent case of diarrhea, and weight-for-age index

Conclusion:

Between 1997 and 2016, anemia rates decreased, showing an epidemiological trend that can contribute to continuously improve the health of children under five years of age in Pernambuco.

Keywords:
Anemia; Child; Nutritional status; Health surveys

INTRODUCTION

Population-based studies of regions and countries are historically recent, accepting as consensual evidence that anemias, as well as deficiencies of vitamins A, D and of iodine, have been the dominant micronutrient deficiencies for several decades¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... , recognized as international collective health priorities and mobilizing research facilities and public interventions aimed at their reduction and possible epidemiological control worldwide.

In the specific case of anemias, given their magnitude and consequences — direct or associated with other comorbidities —, the World Health Organization (WHO) classified them, in 2011, as a serious, permanent, and rising problem in some restricted national or international cases, estimating that one third or at least a quarter of the entire human population had mild, moderate, and severe circulating hemoglobin deficiencies,²2. World Health Organization. The global prevalence of anaemia in 2011 [Internet]. Geneva: WHO; 2015 [acessado em 05 jun. 2022]. Disponível em: https://apps.who.int/iris/bitstream/handle/10665/177094/9789241564960_eng.pdf
https://apps.who.int/iris/bitstream/hand... which characterize, from a laboratory perspective, the elective indicator of a specific deficiency¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... , mainly due to qualitative and quantitative restrictions of iron in the diet³3. Mello CS, Barros KV, Morais MB. Alimentação do lactente e do pré-escolar brasileiro: revisão da literatura. J Pediatr (Rio J) 2016; 92: 451-63. https://doi.org/10.1016/j.jped.2016.02.013
https://doi.org/10.1016/j.jped.2016.02.0... .

In 2011, anemia was classified as a moderate to severe public health problem among women of reproductive age and children under five years in most WHO member states²2. World Health Organization. The global prevalence of anaemia in 2011 [Internet]. Geneva: WHO; 2015 [acessado em 05 jun. 2022]. Disponível em: https://apps.who.int/iris/bitstream/handle/10665/177094/9789241564960_eng.pdf
https://apps.who.int/iris/bitstream/hand... ,⁴4. Kassebaum NJ, Jasrasaria R, Naghavi M, Wulf SK, Johns N, Lozano R, et al. A systematic analysis of global anemia burden from 1990 to 2010. Blood 2014; 123: 615-24. https://doi.org/10.1182/blood-2013-06-508325
https://doi.org/10.1182/blood-2013-06-50... ,⁵5. Stevens GA, Finucane MM, De-Regil LM, Paciorek CJ, Flaxman SR, Branca F, et al. Global, regional, and national trends in haemoglobin concentration and prevalence of total and severe anaemia in children and pregnant and non-pregnant women for 1995–2011: a systematic analysis of population-representative data. Lancet Glob Health 2013; 1: e16-25. https://doi.org/10.1016/S2214-109X(13)70001-9
https://doi.org/10.1016/S2214-109X(13)70... . Since 2000, the global prevalence of anemia in children has slowly decreased over the years — from 48% to 39.8% —, and as of 2010, it has been stagnant⁶6. World Health Organization. Global Health Observatory data repository. Mental health, 2019 [Internet]. [acessado em 02 fev. 2023]. Disponível em: https://apps.who.int/gho/data/node.main.MENTALHEALTH?lang=en
https://apps.who.int/gho/data/node.main.... .

As a biological principle, human susceptibility to the problem is universal, and thus, anemia can occur at any life stage, from fetal to old age⁷7. Marques F, Fonseca C, Nunes AR, Belo A, Brilhante D, Cortez J. Contextualizando a elevada prevalência de anemia na população portuguesa: perceção, caracterização e preditores: um sub-estudo do EMPIRE. Medicina Interna 2016; 23: 26-38.. However, on an epidemiological scale, the problem is more relevant in the maternal-child segment, that is, women of reproductive age, especially during pregnancy, and children under five years¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... ,²2. World Health Organization. The global prevalence of anaemia in 2011 [Internet]. Geneva: WHO; 2015 [acessado em 05 jun. 2022]. Disponível em: https://apps.who.int/iris/bitstream/handle/10665/177094/9789241564960_eng.pdf
https://apps.who.int/iris/bitstream/hand... .

In this group, a set of common and interactive factors stands out in the triad reproductive period/pregnancy/growth and in the development of children in the first months and years of life, favoring the occurrence of anemia: on the one hand, pathophysiological processes and on the other, concomitant adverse socio-environmental factors⁸8. Melku M, Alene KA, Terefe B, Enawgaw B, Biadgo B, Abebe M, et al. Anemia severity among children aged 6–59 months in Gondar town, Ethiopia: a community-based cross-sectional study. Ital J Pediatr 2018; 44: 107. https://doi.org/10.1186/s13052-018-0547-0
https://doi.org/10.1186/s13052-018-0547-... , which can be grouped into the so-called “poverty ecosystem”, a very common context in backward or developing countries¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... .

“Poverty ecosystems” cannot be defined as a single model but basically include low household income, unhealthy living and surrounding conditions, low schooling, qualitative and quantitative restrictions of health actions, and limited social services support network⁹9. Abarca ALF, Moraes LM. Ecologia política urbana no estudo da cidade segregada Latino-americana. Revista de Desenvolvimento Econômico. 2019; 2: 274-95. http://dx.doi.org/10.36810/rde.v2i43.6296
https://doi.org/http://dx.doi.org/10.368... .

Studies show that iron deficiency is the most common cause of anemia worldwide. Nevertheless, acute and chronic inflammation, parasitic infestations, and hereditary or acquired diseases that affect the synthesis, production, or survival of red blood cells can cause anemia¹⁰10. World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Vitamin and mineral nutrition information system [Internet]. Geneva: World Health Organization; 2011 [acessado em 11 jun. 2022]. Disponível em: https://apps.who.int/iris/bitstream/handle/10665/85839/WHO_NMH_NHD_MNM_11.1_eng.pdf?sequence=22&isAllowed=y
https://apps.who.int/iris/bitstream/hand... .

The current study, research focused on time trends, could follow two directions. The first has a “spontaneous” nature and mainly involves the course of changes that happened in the significant process of nutritional transition, very characteristic of the last decades of the previous century¹¹11. Carneiro LBV, Castro IRR, Juvanhol LL, Gomes FS, Cardoso LO. Associação entre insegurança alimentar e níveis de hemoglobina e retinol em crianças assistidas pelo Sistema Único de Saúde no Município do Rio de Janeiro, Brasil. Cad Saude Publica 2019; 36: e00243418. https://doi.org/10.1590/0102-311X00243418
https://doi.org/10.1590/0102-311X0024341... . Although marked by the transition from malnutrition to overweight/obesity, this stage also shifts the temporal course of specific nutritional deficiencies, such as anemias¹²12. Borges GM. Health transition in Brazil: regional variations and divergence/convergence in mortality. Cad Saúde Pública 2017; 33: e00080316. https://doi.org/10.1590/0102-311X00080316
https://doi.org/10.1590/0102-311X0008031... .

Precisely for being an aspect that is little valued in conventional studies, we chose to address the possible temporal shifts that could be affecting anemia in the most vulnerable group of children, that is, those under five years in a geographical area recognized as poor¹³13. Zuffo CRK, Osório MM, Taconeli CA, Schmidt ST, Silva BHC, Almeida CCB. Prevalence and risk factors of anemia in children. J Pediatr (Rio J) 2016; 92: 353-60. https://doi.org/10.1016/j.jped.2015.09.007
https://doi.org/10.1016/j.jped.2015.09.0... .

The other, more interventionist than spontaneous, component would consider possible trends in objectives and goals of the millennium, such as the adherence of governments and international institutions to new and necessary panels in the context of policies and programs for public or governmental interventions¹⁴14. Chen Q, Pei C, Bai Y, Zhao Q. Impacts of nutrition subsidies on diet diversity and nutritional outcomes of primary school students in rural northwestern China-do policy targets and incentives matter? Int J Environ Res Public Health 2019; 16: 2891. https://doi.org/10.3390/ijerph16162891
https://doi.org/10.3390/ijerph16162891... . In reality, a favorable or desired expectation is created to improve the incidence/prevalence levels of problems such as nutritional anemias in higher-risk groups, as is the case of children and women of reproductive age, especially during pregnancy.

Based on these two “axial” foci, we contemplated analyzing possible prospective trends since 1997 in the state of Pernambuco. An additional argument is the great relevance of hemoglobin deficiency in children, which produces very specific adverse consequences for this critical biological transition, leading to changes in neurotransmission and myelination of nerve fibers¹⁵15. Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL. Global burden of disease and risk factors. Washington: World Bank; 2006. https://doi.org/10.1596/978-0-8213-6262-4
https://doi.org/10.1596/978-0-8213-6262-... , with implications for neuropsychomotor development and its impacts on learning, social performance, and ideo-affective processes, increasingly required for human development¹⁶16. Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anaemia. Lancet 2016; 387: 907-16. https://doi.org/10.1016/S0140-6736(15)60865-0
https://doi.org/10.1016/S0140-6736(15)60... ,¹⁷17. Machado EHS, Leone C, Szarfarc SC. Deficiência de ferro e desenvolvimento cognitivo. Rev Bras Crescimento Desenvolv Hum 2011; 21: 368-73. .

As the only state to have carried out periodic health and nutrition surveys of the population since 1992, with a special focus on the maternal-child domain, Pernambuco is very well suited to meet the objectives of temporal assessments.

Thus, this study aimed to analyze the temporal evolution of anemia in children aged six to 59 months in Pernambuco based on population surveys from 1997, 2006, and 2016 and the factors associated with the situation in 2016.

METHODS

This is a cross-sectional study with a database scope and an observational, descriptive, and analytical design. We used secondary data extracted from databases — collected at the Public Health Laboratory of Universidade Federal de Pernambuco (UFPE) — of the State Health and Nutrition Survey (Pesquisa Estadual de Saúde e Nutrição — PESN) II, III, and IV, performed in Pernambuco in 1997, 2006, and 2016, respectively.

The study population comprised children aged six to 59 months of both sexes, living in Pernambuco in 1997, 2006, and 2016, that is, covering almost 20 years. The first two investigations (1997 and 2006) used prevalence rates of anemia already published in scientific articles — 40.9% in a sample of 777 children for the 1997 PESN¹⁸18. Osório MM, Lira PI, Batista-Filho M, Ashworth A. Prevalence of anemia in children 6-59 months old in the state of Pernambuco, Brazil. Rev Panam Salud Publica 2001; 10: 101-7. https://doi.org/10.1590/s1020-49892001000800005
https://doi.org/10.1590/s1020-4989200100... and 32.8% in a sample of 1,403 children for the 2006 PESN¹⁹19. Leal LP, Batista Filho M, Lira PIC, Figueiroa JN, Osório MM. Prevalência da anemia e fatores associados em crianças de seis a 59 meses de Pernambuco. Rev Saúde Pública 2011; 45: 457-66. https://doi.org/10.1590/S0034-89102011000300003
https://doi.org/10.1590/S0034-8910201100... . In the 2016 PESN, the population consisted of 880 children belonging to the original research database; however, this study analyzed the 727 children whose hemoglobin levels were provided. The reduced size of the study population, compared to PESN III, is due to the unilateral decrease in institutions that funded the resources available for the performance of PESN IV.

The anthropometric evaluation was carried out at the interview by previously trained team members. The measures taken met the WHO recommendations²⁰20. World Health Organization. Physical status: the use and interpretation of anthropometry [Internet]. Geneva: WHO; 1995 [acessado em 17 jun. 2022]. Disponível em: https://apps.who.int/iris/bitstream/handle/10665/37003/WHO_TRS_854.pdf?sequence=1
https://apps.who.int/iris/bitstream/hand... . They were obtained in two stages, based on the following procedures: children under two years were weighed with their mother or guardian and with minimal clothing, in a digital scale (Tanita model – BF-683W/UM028 3601), with a capacity of 150 kg and accuracy of 100 g. Next, the mother or guardian was weighed alone to calculate the difference and record the child's final weight. The weight of children older than two years and mothers was obtained using the same scale, with the individual barefoot and wearing minimal clothing.

Children up to two years were measured (length) in the supine position, using a wooden infantometer, with a range of 100 cm and an accuracy of 0.1 cm. The height of children older than two years was determined by a portable stadiometer (Alturaexact Ltda.) — measured in millimeters, with an accuracy of up to 1 mm throughout its length. The children were placed in the upright position, barefoot, with upper limbs hanging along the body, and the heels, back, and head touching the wooden bar.

Hemoglobin levels were obtained from a capillary blood sample. Hemoglobin was determined using Urit-12 equipment (Medical Electronic Co., Ltd.), with immediate reading. The anemia diagnosis was established based on criteria recommended by the WHO, which considers anemic those children with hemoglobin below 11 g/dL¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... .

Nutritional status was assessed using the following indices based on anthropometric data: weight-for-age (W/A), length/height-for-age (L/A or H/A), and weight-for-length/height (W/L or W/H). The reference standard used to compare the measurements of weight, length/height, and body mass index (BMI) was that recommended by the WHO (Anthro – 2007)²¹21. World Health Organization. WHO anthro for personal computers manual. Version 3.2.2. Software for assessing growth and development of the world's children [Internet]. Geneva: WHO; 2011 [acessado em 02 fev. 2023]. Disponível em: https://cdn.who.int/media/docs/default-source/child-growth/child-growth-standards/software/anthro-pc-manual-v322.pdf?sfvrsn=c4e76522_2
https://cdn.who.int/media/docs/default-s... , complying with the following criteria for the indices W/A, W/L, W/H, and BMI/A: underweight z-score (ZS) <-2; nutritional risk ZS ≥-2 to <-1; nutritional adequacy ZS ≥-1 to ≤1; overweight ZS >1 to <2; and obesity ZS ≥2. The criteria for L/A or H/A indices were: stunted ZS <-2 and normal length/height ZS ≥-2.

The interviews were conducted with the person responsible for the child. In their absence, the interviewer returned up to two times to complete the questionnaire.

The study database produced an ad hoc file and was constructed based on information from Pernambuco surveys in 2016. When necessary, the variables were recoded for statistical analysis according to the proposed objectives and the methodological procedures used.

Since all variables involved in the statistical analysis were categorical or categorized, they were summarized as absolute and relative frequencies. Statistical analyses were performed in the Stata 12.1 software.

We used Poisson regression with robust variance to investigate whether the occurrence of anemia in children aged six to 59 months could be associated with the various independent variables studied. Initially, a bivariate analysis was performed by adjusting simple Poisson regression models to statistically test these associations (using the Wald test) and estimate the crude prevalence ratios (PR) with their respective 95% confidence intervals (95%CI). The final multivariate model derived from the initial model after applying the backward method, set at a 0.05 significance level.

The temporal evolution of anemia in children was verified by the test for trend in proportions, and variations and their respective 95%CI were estimated among the three PESN editions. Values were obtained by the Z test.

The Ethics Committee of Instituto de Medicina Integral Professor Fernando Figueira (Imip) approved this time-trend study under the Certificate of Presentation for Ethical Consideration (Certificado de Apresentação de Apreciação Ética — CAAE) No. 26433219.8.0000.5201, on December 12, 2019.

RESULTS

The prevalence of anemia in PESN IV (2016) among children under five years in Pernambuco was 24.2% (95%CI 20.3–28.5%) — prevalence of 22.5% (95%CI 18.1–27.6%) in the urban inland and the Recife Metropolitan Area (RMA) and of 28.0% (95%CI 21.0–36.4%) in the rural inland, with no statistical difference when comparing both geographic strata: p=0.231.

The mean age of the children studied was 31.5 months (standard deviation, SD=15.3) — 30.8 months (SD=15.4) in the urban area and RMA and 33.4 months (SD=15.0) in rural areas. Male children were predominant in the urban area (54.7%), while rural areas had more females (55.0%), p=0.016.

For the historical series, the sequence of results related to the prevalence of anemia in children aged six to 59 months ranged between 40.9% (1997) and 24.2% (2016). At the midpoint of the timeline, that is, PESN III, the value found was 32.8%. The statistical analysis of the time series, constructed with data from three population-based surveys, adopted the test for trend in proportions corresponding to p<0.001, thus considered significant (95%CI).

We found a downward trend in the prevalence of anemia among children in Pernambuco — a 40% relative reduction.

Table 1 presents the PR of maternal sociodemographic, obstetric, and laboratory variables, revealing a statistically significant relationship with maternal age under 20 years (p=0.05) and maternal hemoglobin levels, defined at the cut-off point <12 g/dL.

When considering the variables of children diagnosed with anemia (Table 2), most risk factors were statistically associated with anemia, such as the child's age (p<0.001), diarrhea in the previous two weeks (p=0.004), and indices in the W/A (p=0.048) and L/A or H/A (p=0.045) ratios.

We obtained the adjusted prevalence rates from the multivariate analysis (Table 3), selecting all variables with p<0.20 in the bivariate analysis to build the initial multivariate regression model. The final multivariate model derived from the initial model, set at a 0.05 significance level.

DISCUSSION

The 1997/2006/2016 historical series unquestionably confirmed the remarkable and even surprising reduction in the prevalence of anemia in children under five years in Pernambuco, dropping from 40.9 to 24.2%, that is, a 40% decrease in less than 20 years. Surely, such a reduction, which would be impressive in any country, means that risk factors have been mitigated or disappeared, which should be reflected in the factorial models analyzed by multivariate statistical tests.

In Brazil (Maceió, Alagoas), a study published in 2017 evaluated the evolution of anemia in children based on two studies conducted in 2005 and 2015, revealing a clear downward trend in this population — from 45.1 to 27.4%²²22. Vieira RCS, Livramento ARS, Calheiros MSC, Ferreira CMX, Santos TR, Assunção ML, et al. Prevalence and temporal trend (2005-2015) of anaemia among children in Northeast Brazil. Public Health Nutr 2018; 21: 868-76. https://doi.org/10.1017/S1368980017003238
https://doi.org/10.1017/S136898001700323... . As in Pernambuco, this drop can be mainly attributed to similar conditions: fortification of highly consumed food products (industrialized wheat and corn foods) with iron and folate²³23. Brasil. Ministério da Saúde. Agência Nacional de Vigilância Sanitária. Resolução-RDC no 344, de 13 de dezembro de 2002. Aprova o Regulamento Técnico para a fortificação das farinha de trigo e milho e das farinhas de milho com ferro e ácido fólico, constante do anexo desta Resolução [Internet]. Brasília: Ministério da Saúde de 18 de dezembro de 2002. [acessado em 20 jun. 2022]. Disponível em: https://bvsms.saude.gov.br/bvs/saudelegis/anvisa/2002/rdc0344_13_12_2002.html#:~:text=a%20sua%20publica%C3%A7%C3%A3o%3A-,Art.,para%20adequa%C3%A7%C3%A3o%20de%20seus%20produtos.
https://bvsms.saude.gov.br/bvs/saudelegi... . In the history of other countries, food fortification with antianemic agents was also a strategically important measure to fix the problem. In a way, this resource has been incorporated into food and nutrition public policies, either as a preventive or generic curative action, specifically aimed at more vulnerable strata of the population, such as children and pregnant women.

By adopting food fortification in 2004, Brazil pragmatically and effectively advanced in the fight against anemias, with more comprehensive, integrated, well-designed, and successful policies, resulting in the great achievement of leaving the hunger map²⁴24. Food and Agriculture Organization of the United Nations. The state of food insecurity in the world [Internet]. 2014 [acessado em 20 jun. 2022]. Disponível em: http://www.fao.org/3/i4030e/i4030e.pdf
http://www.fao.org/3/i4030e/i4030e.pdf... ,²⁵25. O estado da segurança alimentar e nutricional no Brasil. Um retrato multidimensional. Brasília; 2014 [acessado em 21 jun. 2022]. Disponível em: https://www.mds.gov.br/webarquivos/publicacao/seguranca_alimentar/SANnoBRasil.pdf
https://www.mds.gov.br/webarquivos/publi... . Related actions, such as the Bolsa Família Program, the increase in the minimum wage, and the improvement in school meals, led to a substantial reduction in the level of childhood anemia in Pernambuco.

This study, which evaluates the evolution of anemia by analyzing three nutritional surveys in Pernambuco covering the last years of the previous century and the first decade of the 2000s, reveals an initiative that should be promoted and improved. In this regard, 2004 is a historic milestone. The experience learned must be expanded and renewed, following not only the lessons from other countries but especially our own.

The historical trend might not be confirmed, as the low prevalence of anemias in children is a new fact in the latest epidemiological scenario. In other words: the decreased prevalence of anemia among children in Pernambuco (equivalent to 40% between PENS II and IV) implies (and is explained by) the progressive elimination of risk factors. This is the case for groups of variables such as household income, cough, hospitalization in the previous 12 months, and other categories.

The formal logic of possible relationships is denied by the material logic of current standard data. Many variables validated in past surveys of the same population in the same place may lose their validity to new historically changed conditions. When comparing data from 1997 (PESN II) and 2016 (final year of the historical series), the prevalence of anemia among children in Pernambuco had a significant decrease: 40%. Yet, at the same time, the most recent risk factors have undergone a major change. It is the dynamics of facts. Actually, this change occurred in the first 10 years of this century, when food and nutrition problems gained prominence and became high priorities in Brazilian public policies.

We underline that anemia in children was significantly associated with anemia in mothers, which should be considered during prenatal care. Starting the treatment for iron-deficiency anemia in pregnant women as early as possible is essential to optimize its protective effects on the fetus²⁶26. Scholl TO. Maternal iron status: relation to fetal growth, length of gestation, and iron endowment of the neonate. Nutr Rev 2011; 69: S23-9. https://doi.org/10.1111/j.1753-4887.2011.00429.x
https://doi.org/10.1111/j.1753-4887.2011... .

Children under 24 months has a higher prevalence of anemia (37.7%) compared to those older than 24 months (21.2%). This statistically significant difference between prevalence rates might result from the accelerated growth and consequent increase in the nutritional needs of younger children, in addition to early weaning and a diet poor in nutrients and often very monotonous, derived from a previous predominantly dairy diet²⁷27. Gondim SSR, Diniz AS, Souto RA, Bezerra RGS, Albuquerque EC, Paiva AA. Magnitude, tendência temporal e fatores associados à anemia em crianças do Estado da Paraíba. Rev Saúde Pública 2012; 46: 649-56. https://doi.org/10.1590/S0034-89102012005000055
https://doi.org/10.1590/S0034-8910201200... . A similar situation was found in a study conducted in Gondar, Ethiopia, which identified a higher prevalence of anemia in children under 11 months (48.9%) compared to the age group of 48 to 59 months (8.9%)⁵5. Stevens GA, Finucane MM, De-Regil LM, Paciorek CJ, Flaxman SR, Branca F, et al. Global, regional, and national trends in haemoglobin concentration and prevalence of total and severe anaemia in children and pregnant and non-pregnant women for 1995–2011: a systematic analysis of population-representative data. Lancet Glob Health 2013; 1: e16-25. https://doi.org/10.1016/S2214-109X(13)70001-9
https://doi.org/10.1016/S2214-109X(13)70... . In Peru, a higher prevalence of anemia was also detected in children aged six to 12 months, 87.3%, contrasting with 58.7% in the age group of 19 to 36 months²⁸28. Gosdin L, Martorell R, Bartolini RM, Mehta R, Srikantiah S, Young MF. The co-occurrence of anaemia and stunting in young children. Matern Child Nutr. 2018; 14: e12597. https://doi.org/10.1111/mcn.12597
https://doi.org/10.1111/mcn.12597... .

The report of diarrhea in the two weeks prior to the interview was associated with anemia in children, both when assessed separately in the bivariate analysis and together with other determinants in the multivariate model. This association also occurred in the 1997 PESN¹⁸18. Osório MM, Lira PI, Batista-Filho M, Ashworth A. Prevalence of anemia in children 6-59 months old in the state of Pernambuco, Brazil. Rev Panam Salud Publica 2001; 10: 101-7. https://doi.org/10.1590/s1020-49892001000800005
https://doi.org/10.1590/s1020-4989200100... , but not in 2006¹⁹19. Leal LP, Batista Filho M, Lira PIC, Figueiroa JN, Osório MM. Prevalência da anemia e fatores associados em crianças de seis a 59 meses de Pernambuco. Rev Saúde Pública 2011; 45: 457-66. https://doi.org/10.1590/S0034-89102011000300003
https://doi.org/10.1590/S0034-8910201100... , as diarrhea was not selected for the final model in this year. The predisposition to anemia after an episode of acute infection, such as diarrhea, is evident, but its effects depend on the severity and duration of the process in order to become a detectable risk factor for anemia²⁹29. Roncalli AG, Lima KC. Impacto do Programa Saúde da Família sobre indicadores de saúde da criança em municípios de grande porte da região Nordeste do Brasil. Ciênc Saúde Coletiva 2006; 11: 713-24. https://doi.org/10.1590/S1413-81232006000300018
https://doi.org/10.1590/S1413-8123200600... .

The association identified in this study between anemia and nutritional deficiency, demonstrated by the W/A and L/A or H/A indices, is also described in PESN III¹⁹19. Leal LP, Batista Filho M, Lira PIC, Figueiroa JN, Osório MM. Prevalência da anemia e fatores associados em crianças de seis a 59 meses de Pernambuco. Rev Saúde Pública 2011; 45: 457-66. https://doi.org/10.1590/S0034-89102011000300003
https://doi.org/10.1590/S0034-8910201100... , whose indices were statistically significant compared to anemia in both investigations. This finding corroborates a study carried out in Bangladesh, which revealed that malnourished children had a higher prevalence of anemia³⁰30. Yusuf A, Mamun ASMA, Kamruzzaman M, Saw A, El-Fetoh NM, et al. Factors influencing childhood anaemia in Bangladesh: a two level logistic regression analysis. BMC Pediatr 2019; 19: 213. https://doi.org/10.1186/s12887-019-1581-9
https://doi.org/10.1186/s12887-019-1581-... , and another from Nepal, where underweight children were more likely to have moderate to severe anemia³¹31. Chowdhury MRK, Khan MMH, Khan HTA, Rahman MS, Islam MR, Islam MM, et al. Prevalence and risk factors of childhood anemia in Nepal: a multilevel analysis. PLoS One 2020; 15: e0239409. https://doi.org/10.1371/journal.pone.0239409
https://doi.org/10.1371/journal.pone.023... .

The lack of information on the food consumption of children under five years is the main limitation to the interpretation of our results. The nutritional value of the diet is crucial when analyzing the problem of anemia, since its most common cause in children is iron deficiency¹1. World Health Organization. Nutritional anaemias: tools for effective prevention and control [Internet]. Geneva: WHO; 2017 [acessado em 05 jun. 2022]. Disponível em: https://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/
https://www.who.int/nutrition/publicatio... , usually associated with insufficient intake of this micronutrient or the consumption of foods that inhibit its absorption in the digestive tract²⁷27. Gondim SSR, Diniz AS, Souto RA, Bezerra RGS, Albuquerque EC, Paiva AA. Magnitude, tendência temporal e fatores associados à anemia em crianças do Estado da Paraíba. Rev Saúde Pública 2012; 46: 649-56. https://doi.org/10.1590/S0034-89102012005000055
https://doi.org/10.1590/S0034-8910201200... .

We highlight that between 1997 and 2016, the prevalence of anemia gradually decreased in children aged six to 59 months in Pernambuco, evidencing a downward epidemiological trend. Nonetheless, our most expressive and even historical contribution was revealing the remarkable and consistent evidence that anemia has a new perspective among children in Pernambuco, the Northeast Region, and possibly Brazil, by dropping from 40.9 to 24.2% in less than 20 years.

Publications showing that anemia, as well as vitamin A deficiency, in children²⁵25. O estado da segurança alimentar e nutricional no Brasil. Um retrato multidimensional. Brasília; 2014 [acessado em 21 jun. 2022]. Disponível em: https://www.mds.gov.br/webarquivos/publicacao/seguranca_alimentar/SANnoBRasil.pdf
https://www.mds.gov.br/webarquivos/publi... and pregnant women has been decreasing in a seemingly consistent way justify the organization of a forum to discuss and forward these problems at the national or, at least, regional level, so as to obtain technical and even political-administrative positions on these issues, which should not be limited to the purely academic domain of dissertations and theses.

ACKNOWLEDGEMENTS:

We thank the Nutrition Department of Universidade Federal de Pernambuco and the Nutrition Study Group of Instituto de Medicina Integral Professor Fernando Figueira for providing the database that comprised the research results

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