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What are the challenges to addressing anemia?

The Challenges of Addressing Anemia

Although anemia can be a very dangerous condition, it is also both preventable and treatable. However, if anemia is so damaging, why haven’t we been able to do a better job of addressing it? The answers are varied across complex diagnosis, control, and policy challenges.

Anemia can emerge from any of several causes that are difficult to distinguish from each other. It can be difficult to diagnose the underlying cause and apply appropriate treatment.

  • Lack of data for attribution: Many types of anemia can appear concurrently, and the presentations of several might be similar. Accurate global attribution estimates require more data.
  • Over-attribution to iron deficiency anemia: A systematic analysis of global anemia burden found that most global cause-specific analyses of anemia tend to focus on the most common cause: iron deficiency.1 Anemia is often ascribed to this condition – no matter the actual cause2 – but in actuality, only about half of anemia cases worldwide are due to insufficient iron.3
  • Biomarker complexity: Various biomarkers can be tested to assess the cause of anemia (e.g., ferritin, serum retinol), but they have varying sensitivities and specificities. The difficulty is further compounded by the complex interactions of these biomarkers and other biological factors such as inflammation, nutrient deficiency, and pregnancy.4 Especially in low- and middle-income countries (LMICs), several types of anemia may occur concurrently, making biomarkers difficult to interpret.

Global standards for anemia diagnosis have several limitations. The diagnosis of anemia is based on Hb levels in the blood, with cutoff levels established to define severe, moderate, and mild anemia. However, current cutoffs are based on the population distribution of Hb values in women in high-income settings, and therefore present three fundamental problems:

  • Outdated definitions not driven by functional outcomes: The cutoff for anemia diagnosis is based on the fifth percentile of Hb distributions from the United States in the 1960s. Methods and data were never published. Thresholds often do not match those used in clinical practice – resulting in statistically but not functionally usable cutoffs.5,6
  • Incomplete epidemiological definitions: Anemia cutoffs are contextual, accounting for age, sex, altitude, smoking status, and pregnancy status.7,8
  • Variation across regions: The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia project pooled multinational measurements of the fifth percentile of Hb among healthy WRA, which ranged from 92 to 121 g/dL in different countries. Compared to the current WHO Hb cutoff of 110 g/dL for mild anemia diagnosis,9 this suggests variation in how cutoffs apply across geographies and in LMICs.

WHO has recommitted to defining new Hb thresholds as part of a larger initiative addressing anemia, including developing Hb thresholds based on gestational age to better relate pregnancy- and health-related outcomes to anemia diagnosis.

This initiative extends beyond pregnancy-related diagnosis and also looks to assess Hb thresholds for several other cohorts, including children, across geographies.

Maternal hemoglobin levels by gestational age and percentile, compared to WHO cut-offs for anemia diagnosis in pregnant women

At an individual level, diagnosing anemia presents some unique field-level difficulties.10 The ability to diagnose anemia in patients and move them to treatment depends on the training, service availability, and use of health service providers in the region. In LMICs, this can be an extremely limiting factor in getting to most at-risk populations.

At a population level, estimating anemia burden is difficult in the field. Accurate diagnostics require obtaining blood samples, which is challenging to implement at a population level.1 Especially in LMIC settings, arranging access to biochemical or hematological testing is difficult. The most common test in LMIC settings is the HemoCue analyzer, due to portability and ease of administration. Unfortunately, this machine requires frequent calibration and a specific administration protocol, and sampling technique is difficult to train and provide quality control for.11,12

A major lever for addressing anemia among WRA is iron plus folic acid (IFA) supplementation, but several bottlenecks exist in coverage and uptake. Globally, IFA programs are the most common type of supplementation. Many nations have implemented them nationally for many decades under varying designs, such as through both over-the-counter and health care facility settings. However, adherence remains low, due to multifaceted issues of supply: quality and coverage of antenatal care, IFA supply chain, and provider provision and explanation of supplementation; and demand: sociocultural attitudes to receiving health care services and motivation to take IFA.13 Further, there are difficulties estimating IFA program coverage to assess effectiveness.14

Guidance varies as to what supplementation and fortification should be provided and when. Although WHO guidelines continue to recommend IFA for WRA,15 a growing body of evidence shows the benefits of multiple micronutrient supplementation (MMS) on positive birth outcomes.16 However, further evidence gaps exist concerning the relative benefits of IFA versus MMS in different anemia-burdened populations, as well as the relative costs of distribution and policy change.17 Iron supplementation and fortified foods carry risks. Iron-fortified foods can negatively influence the composition of gut microbiota, causing intestinal inflammation, especially in settings where hygiene standards are low.18 Unabsorbed iron can also damage the gut microbiota, such as when consumed in foods that decrease bioavailability.19 This has been shown mostly among nonanemic populations, creating complexity around guidance to use iron fortification as a preventative method. Further, one study suggests that the interaction between malaria and IFA may increase risk of severe health outcomes. The World Health Organization (WHO) recommends iron supplementation to reduce risk of anemia only when malaria prevention and management services are present in malaria-endemic regions.20,21,22

Anemia is a highly intersectoral issue requiring governance, collaboration across sectors, political commitment, and fundamental improvements in socioeconomic environment. Interventions are required at a much broader level, including health care service access and quality, economic welfare, and education. The LMIC communities often most burdened by anemia are also often hardest to reach and most difficult to scale up programs in.

The Current State of the Global Campaign Against Anemia

Progress to Date

For certain measures, the world has made considerable progress against anemia over the past two decades.

Each WHO region was able to reduce prevalence of anemia among WRA during the years 2000–2019.

Anemia prevalence among WRA by WHO region

In addition, the overall profile of anemia cases has become less dire, with fewer severe cases and a higher proportion of mild cases.

Anemia prevalence among WRA by WHO region by anemia severity

Gains against anemia have been especially pronounced in certain areas.
  • The WHO Western Pacific and European regions have reduced the number of anemic women of reproductive age on an absolute basis. The Western Pacific’s reduction in cases from 96 million in 2000 to 60 million in 2019 is especially noteworthy.23
  • Several countries have demonstrated a reduction in anemia prevalence in nonpregnant women, as indicated by repeated national surveys in the Sixth Report on the World Nutrition Situation, compiled by the United Nations Standing Committee on Nutrition.
    • China decreased prevalence from 50 percent to 19.9 percent in 21 years (1981–2002)
    • Nepal from 65 percent to 34 percent in 8 years (1998–2006)
    • Sri Lanka from 59.8 percent to 31.9 percent in 13 years (1988–2001)
    • Cambodia from 56.2 percent to 44.4 percent in 6 years (2000–2006)
    • Vietnam from 40 percent to 24.3 percent in 14 years (1987–2001)
    • Guatemala from 35 percent to 20.2 percent in 7 years (1995–2002). 24,25

Pitfalls to Date

Nevertheless, not all the news on anemia is positive. Globally, there has been little progress in reducing the prevalence of anemia among WRA over the last decade, with global prevalence stagnated at approximately 30 percent. This lack of progress is particularly stark in South Asia and sub-Saharan Africa, where prevalence has increased over this time in some countries.21 The second Global Nutrition Target 2025 calls for a 50 percent reduction of anemia in WRA. However, no country is on track to achieve this goal.26

  1. 1
    Kassebaum NJ, Jasrasaria R, Naghavi M, et al. A systematic analysis of global anemia burden from 1990 to 2010. Blood. 2014;123:615-24. Accessed September 25, 2021. https://doi.org/10.1182/blood-2013-06-508325
  2. 2
    Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anemia. Lancet. 2016;387(10021):907-916. https://doi.org/10.1016/S0140-6736(15)60865-0
  3. 3
    World Health Organization/United Nations Children’s Fund/United Nations University. Iron Deficiency Anaemia Assessment, Prevention and Control: A Guide for Programme Managers. World Health Organization; 2001. Accessed September 25, 2021. http://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf
  4. 4
    Wirth JP, Woodruff BA, Engle-Stone R, et al. Predictors of anemia in women of reproductive age: biomarkers reflecting inflammation and nutritional determinants of anemia (BRINDA) project. Am J Clin Nutr. 2017;106(Suppl):416S-427S. Accessed September 25, 2021. https://doi.org/10.3945/ajcn.116.143073
  5. 5
    Sachdev HS, Porwal A, Acharya R, Ashraf S, Ramesh S, Khan N. Haemoglobin thresholds to define anaemia in a national sample of health children and adolescents aged 1-19 years in India: a population-based study. Lancet. 2021;9(6):E822-E831. Accessed September 25, 2021. https://doi.org/10.1016/S2214-109X(21)00077-2
  6. 6
    Pasricha SR, Colman K, Centeno-Tablante E, Garcia-Casal MN. Revisiting WHO haemoglobin thresholds to define anaemia in clinical medicine and public health. Lancet Haematol. 2018;5:e60-e62. Accessed September 25, 2021. https://doi.org/10.1016/S2352-3026(18)30004-8
  7. 7
    Northrop-Clewes CA, Thurnham DI. Biomarkers for the differentiation of anemia and their clinical usefulness. J Blood Med. 2013;4:11-22. Accessed September 25, 2021. https://doi.org/10.2147/JBM.S29212
  8. 8
    World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. World Health Organization; 2011. WHO/NMH/NHD/MNM/11.1. Accessed October 5, 2021. https://www.who.int/vmnis/indicators/haemoglobin.pdf
  9. 9
    Addo Y, Yu EX, Williams A, et al. Evaluation of hemoglobin cutoffs for defining anemia in a multinational sample of healthy individuals: the BRINDA project (OR07-07-19). Curr Dev Nutr. 2019;3(Suppl 1):nzz034.OR07-07-19. https://doi.org/10.1093/cdn/nzz034.OR07-07-19
  10. 10
    Freeman AM, Rai M, Morando DW. Anemia Screening. Updated July 31, 2021. StatPearls [Internet]. StatPearls Publishing; 2021. Accessed October 5, 2021. https://www.ncbi.nlm.nih.gov/books/NBK499905/
  11. 11
    Neufeld L, et al. Hemoglobin concentration and anemia diagnosis in venous and capillary blood: biological basis and policy implications. Ann N Y Acad Sci. 2019;1450(1):172-189. Accessed October 5, 2021. https://doi.org/10.1111/nyas.14139
  12. 12
    Parker M, Han Z, Abu-Haydar E, et al. An evaluation of hemoglobin measurement tools and their accuracy and reliability when screening for child anemia in Rwanda: A randomized study. PLoS One. Accessed September 29, 2021. 2018;13(1):e0187663. https://doi.org/10.1371/journal.pone.0187663
  13. 13
    Sununtnasuk C, D'Agostino A, Fiedler JL. Iron+folic acid distribution and consumption through antenatal care: identifying barriers across countries. Public Health Nutr. 2016;19(4):732-742. Accessed September 25, 2021. https://neuro.unboundmedicine.com/medline/citation/26022914
  14. 14
    Kanyangarara M, Katz J, Munos MK, Khatry SK, Mullany LC, Walker N. Validity of self-reported receipt of iron supplements during pregnancy: implications for coverage measurement. BMC Pregnancy Childbirth. 2019;19(1):113. https://doi.org/10.1186/s12884-019-2247-1
  15. 15
    World Health Organization. Iron with or Without Folic Acid Supplementation in Women. World Health Organization; 2018. Accessed March 20, 2021. https://www.who.int/elena/titles/full_recommendations/ifa_supplementation/en/
  16. 16
    Tuncalp Ö, Rogers LM, Lawrie TA, et al. WHO recommendations on antenatal nutrition: an update on multiple micronutrient supplements. BMJ Glob Health. 2020;5(7):e003375. https://doi.org/10.1136/bmjgh-2020-003375
  17. 17
    Black RE, Dewey KG. Benefits of supplementation with multiple micronutrients in pregnancy. Ann N Y Acad Sci. 2019;1444(1):3-5. https://doi.org/10.1111/nyas.14088
  18. 18
    Jaeggi T, Kortman GAM, Moretti D, et al. Iron fortification adversely affects the gut microbiome, increases pathogen abundance and induces intestinal inflammation in Kenyan infants. Gut. 2015;64:731. Accessed September 25, 2021. https://doi.org/10.1136/gutjnl-2014-307720
  19. 19
    Rusu IG, Suharoschi R, Vodnar DC, et al. Iron supplementation influence on the gut microbiota and probiotic intake effect in iron deficiency: a literature-based review. Nutrients. 2020;12(7):1993. https://doi.org/10.3390/nu12071993
  20. 20
    McClung JP. Iron supplementation in children with malaria: timing the treatment. J Nutr. 2016;146(9):1623-1624. Accessed October 5, 2021. https://doi.org/10.3945/jn.116.236463
  21. 21
    Neuberger A, Okebe J, Yahav D, Paul M. Oral iron supplements for children in malaria-endemic areas. Cochrane Database Syst Rev. 2016;2:CD006589. Accessed October 5, 2021. https://doi.org/10.1002/14651858.CD006589.pub4
  22. 22
    World Health Organization. Guideline: Daily Iron Supplementation in Infants and Children. WHO Press; 2016. https://www.ncbi.nlm.nih.gov/books/NBK362032/
  23. 23
    Institute for Health Metrics and Evaluation (IHME). Global Burden of Disease (GBD). IHME. 2019. Accessed September 21, 2021. http://www.healthdata.org/gbd/2019
  24. 24
    World Health Organization. Comprehensive Implementation Plan on Maternal, Infant and Young Child Nutrition. World Health Organization; 2014. Accessed September 25, 2021.  https://apps.who.int/iris/bitstream/handle/10665/113048/WHO_NMH_NHD_14.1_eng.pdf
  25. 25
    United Nations. Sixth Report on the World Nutrition Situation: Progress in Nutrition. United Nations Standing Committee on Nutrition; 2010. https://www.unscn.org/files/Publications/RWNS6/html/
  26. 26
    Keats EC, Neufeld LM, Garrett GS, Nmuya MNN, Bhutta ZA. Improved micronutrient status and health outcomes in low- and middle-income countries following large-scale fortification: evidence from a systematic review and meta-analysis. Am J Clin Nutr. 2019;109(6):1696-1708. https://doi.org/10.1093/ajcn/nqz023
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