Sustainable Development Goals for anaemia: 20 years later, where are we now?
Authors: Jahnavi Daru
Journal: The Lancet Global Health (2022)

Maternal and infant anaemia has profound, well known consequences, including an increased risk of postpartum haemorrhage, infection and maternal mortality for women; and low birthweight and poor neurocognitive and motor development in children.1Daru J Zamora J Fernández-Félix BM et al.Risk of maternal mortality in women with severe anaemia during pregnancy and post partum: a multilevel analysis.Lancet Glob Health. 2018; 6: e548-e554Summary Full Text Full Text PDF PubMed Scopus (122) Google Scholar, 2Rahman MM Abe SK Rahman MS et al.Maternal anemia and risk of adverse birth and health outcomes in low-and middle-income countries: systematic review and meta-analysis.Am J Clin Nutr. 2016; 103: 495-504Crossref PubMed Scopus (240) Google Scholar As a result, prevention and swift treatment of anaemia was included in the UN Sustainable Development Goals (SDGs) in 2012, with the intention of halving anaemia prevalence in women of reproductive age by 2030—a bold and progressive target.3WHOUNICEFWHO/UNICEF Discussion Paper. The extension of the 2025 maternal, infant and young child nutrition targets to 2030.https://data.unicef.org/resources/who-unicef-discussion-paper-nutrition-targets/Date: June, 2019Date accessed: March 17, 2022Google Scholar In their study in The Lancet Global Health, Gretchen Stevens and colleagues4Stevens GA Paciorek CJ Flores-Urrutia MC et al.National, regional, and global estimates of anaemia by severity in women and children for 2000–19: a pooled analysis of population-representative data.Lancet Glob Health. 2022; 10: e627-e639Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar provide global estimates of anaemia prevalence using a Bayesian hierarchical model developed from data collected from multiple sources between 2000 and 2019 following systematic searches. Although this study may not be a direct comparison with previously published estimates,5Stevens GA Finucane MM De-Regil LM 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-e25Summary Full Text Full Text PDF PubMed Scopus (935) Google Scholar it is a sobering read showing that little progress has been made in reducing anaemia prevalence globally in the past few decades, with overall estimates decreasing from 31% to 30% in non-pregnant women and decreasing from 41% to 36% in pregnant women globally between 2000 and 2019. In infants and children, the overall prevalence of anaemia in 2019 was 40%, and more than 70% in 11 countries sampled (Yemen and ten countries in west and central Africa). There might be several reasons for these estimates, including the cause of anaemia and how it is measured. Causes of anaemia are multifactorial, including nutritional deficiencies (ie, those of iron and other micronutrients), inherited haemoglobinopathies, and infectious diseases,6Lopez A Cacoub P Macdougall IC Peyrin-Biroulet L Iron deficiency anaemia.Lancet. 2016; 387: 907-916Summary Full Text Full Text PDF PubMed Scopus (649) Google Scholar many of which are combined in some populations, making it challenging to determine which factors are driving the prevalence seen within a country or region. Beyond this, systemic factors such as poverty, access to health care, food fortification, and sanitation also contribute to anaemia.7Balarajan Y Ramakrishnan U Özaltin E Shankar AH Subramanian S Anaemia in low-income and middle-income countries.Lancet. 2011; 378: 2123-2135Summary Full Text Full Text PDF PubMed Scopus (564) Google Scholar With all these moving parts, Stevens and colleagues4Stevens GA Paciorek CJ Flores-Urrutia MC et al.National, regional, and global estimates of anaemia by severity in women and children for 2000–19: a pooled analysis of population-representative data.Lancet Glob Health. 2022; 10: e627-e639Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar should be acknowledged for their efforts to highlight the progress made in anaemia prevalence globally. It is important to emphasise that in this study, all-cause anaemia prevalence is estimated rather than due to one specific factor (eg, anaemia secondary to iron deficiency). This leads to the question of what is anaemia, and why is it so hard to treat? For the most part, a fall in haemoglobin concentration below a defined level leads to the diagnosis of anaemia, with or without a deficiency of micronutrients. In some situations, anaemia can be physiological. For example in pregnancy, as plasma volume expands in the first trimester, the measured concentration of haemoglobin falls.8Vricella LK Emerging understanding and measurement of plasma volume expansion in pregnancy.Am J Clin Nutr. 2017; 106: 1620S-1625SCrossref PubMed Scopus (35) Google Scholar Therefore, the definition used for anaemia will be a driving factor in the prevalence observed. In this study, Stevens and colleagues used the existing WHO definitions,9WHOHaemoglobin concentrations for the diagnosis of anaemia and assessment of severity.https://apps.who.int/iris/handle/10665/85839Date: 2011Date accessed: March 17, 2022Google Scholar and showed that prevalence of moderate (haemoglobin concentrations between 70–99 g/L in children and pregnant women and 80–109 g/L in non-pregnant women) and severe anaemia (haemoglobin concentrations <70 g/L in children and pregnant women and <80 g/L in non-pregnant women) is generally improving globally, with a trend towards mild to moderate anaemia. What is not clear, however, is the impact of such a shift on clinical, physiological, and functional outcomes. Currently, an active area of research includes determining whether the existing definitions of anaemia and micronutrient deficiencies used by WHO require revision.10Pasricha SR Colman K Centeno-Tablante E Garcia-Casal MN Pena-Rosas JP Revisiting WHO haemoglobin thresholds to define anaemia in clinical medicine and public health.Lancet Haematol. 2018; 5: e60-e62Summary Full Text Full Text PDF PubMed Scopus (36) Google Scholar This will affect anaemia prevalence in the future. The data used in this work are from a variety of sources, combining individual-level and summary data from national registries, WHO surveys, and databases providing a comprehensive dataset. The authors were fortunate to have a large sample of haemoglobin measures (>4 million), meaning the precision of their estimates is excellent, but we cannot assume perfect validity. Given the wealth of data derived from numerous countries, the authors have published country-specific estimates of anaemia prevalence, which are available on WHO's Global Health Observatory and in the appendix. Although impressive, these data are also a source of heterogeneity in the overall estimates. Nevertheless, these estimates will hopefully allow national policy makers to better understand what aspects of their anaemia prevention strategies need further work. This important piece of research shows that anaemia prevalence appears to have changed little globally in the past 20 years and the SDG targets for anaemia reduction might still be beyond reach by 2030. However, some countries in these analyses have shown improvements in anaemia prevalence, such as Guatemala and the Philippines. This finding suggests that there might be hope for other countries to follow suit. However, in order for real global progress to be made, systematic, multifactorial changes with a focus on managing the complexity of anaemia are needed by politicians, policy makers, and clinicians. Without continuing the momentum, we run the risk of ignoring this important, seemingly simple problem. Lisa Rogers and Gretchen Stevens and I have worked together on a meeting on haemoglobin thresholds in June, 2021. I declare no other competing interests. National, regional, and global estimates of anaemia by severity in women and children for 2000–19: a pooled analysis of population-representative dataGlobally, regionally, and in nearly all countries, progress on anaemia in women aged 15–49 years is insufficient to meet the WHA global nutrition target to halve anaemia prevalence by 2030, and the prevalence of anaemia in children also remains high. A better understanding of the context-specific causes of anaemia and quality implementation of effective multisectoral actions to address these causes are needed. Full-Text PDF Open Access