Iron deficiency anaemia in sub-Saharan Africa: a review of current evidence and primary care recommendations for high-risk groups

Summary

The epidemiology of iron deficiency anaemia in sub-Saharan Africa differs from that in other parts of the world. The low-quality diets prevalent in this region are a poor source of iron, the population is frequently exposed to infection, and demographic characteristics result in a greater prevalence of people at high risk of iron deficiency anaemia than in other parts of the world. We herein review the causes, disease burden, and consequences of iron deficiency anaemia in the general population in this region, and current policies and interventions for its control. The current debate is dominated by concerns about the safety of iron interventions, namely regarding its effects on malaria and other infectious diseases. However, universal antenatal iron supplementation and delayed cord clamping are safe interventions and stand out for their potential to improve maternal and infant health. Effective infection control is a precondition to safe and efficacious iron interventions in children. Greater emphasis should be given to approaches aiming to reduce iron loss due to helminth infections and menstruation, alongside interventions to increase iron intake.

Translation

For the French translation of the abstract see Supplementary Materials section.

Introduction

The epidemiology of iron deficiency anaemia in sub-Saharan Africa differs from that in other parts of the world in three key aspects. First, despite rapid urbanisation, sub-Saharan Africa continues to have the largest share of rural population of all the world regions that are reliant on monotonous, plant-based diets.¹ The staple foods of these populations are usually comprised of unrefined grains and derived products (eg, flour), which are naturally rich in substances that inhibit the intestinal absorption of non-haem iron. The low bioavailability of dietary iron partly explains why the prevalence of anaemia in sub-Saharan Africa is higher than in any other region worldwide.² Second, people in sub-Saharan Africa are disproportionally exposed to infections. Concerns that iron interventions can increase the burden of infectious diseases, notably malaria, have been a barrier to scaling up iron interventions. Conversely, infections cause iron deficiency through blood loss and inflammation, and complicate the diagnosis of iron deficiency. Evidence is growing that infection-induced inflammation, even at low-grade levels, impairs the efficacy of iron interventions in Africa. Finally, because of demographic factors, groups at risk of iron deficiency anaemia remain disproportionally represented in Sub-Saharan Africa. The region also has the highest proportion of children younger than 5 years (15·4% of the total population, in 2019) of any world region.³ It is also the only region in the world where the population is forecasted to continuously grow over the next 80 years, from 13% (1·2 billion people, in 2017) to 35% (3·1 billion people, in 2100) of the global population.⁴ These forecasts are mostly driven by high fertility, so a large proportion of the sub-Saharan African population will, in the coming decades, be constituted of pregnant women and young children—two groups that are at high risk of iron deficiency anaemia. In sub-Saharan Africa, early childbearing is also generally more frequent than elsewhere in the world. In west and central Africa, 28% of women aged 20–24 years surveyed reported to have had a livebirth by their 18th birthday (with 6% of these women reporting to have had a livebirth by their 15th birthday); in eastern and southern Africa, this percentage was 25% for women of the same age (with 4% of these women reporting to have had a livebirth by their 15th birthday).⁵ In these adolescents, high iron requirements due to pregnancy are superimposed on those for growth, which is likely to put them at high risk of severe, life-threatening anaemia during pregnancy or after childbirth.

Key messages

Pregnant women

• Adherence to iron supplementation during pregnancy is likely to lead to substantial reduction in post-partum, haemorrhage-induced maternal mortality and to increased birthweight

• National programmes for antenatal iron supplementation urgently need strengthening or overhauling and international financial and technical support to improve delivery and create demand

Adolescent girls and non-pregnant women

• Sufficient iron stores should be attained before pregnancy or between pregnancies to prevent iron deficiency and anaemia during pregnancy; insufficient attention is given in research and policies to adolescent girls, perhaps on the grounds that iron deficiency anaemia is relatively uncommon in this group

• Policies should be reviewed to give women of reproductive age, including adolescent girls, access to contraceptives with the specific aim of controlling menstrual bleeding and its associated anaemia, and to build iron stores

Children

• Delayed cord clamping can prevent or delay the onset of iron deficiency anaemia in late infancy, when children are most susceptible

• As per WHO recommendations, iron interventions should not be given to children in malaria-endemic areas unless given in conjunction with measures to prevent malaria, which should be administered to individual recipients of iron interventions, rather than to a general public receiving iron interventions

General

• Effective control of infections, especially in sub-Saharan Africa, is required to improve iron absorption and utilisation, and to make iron interventions safe and more efficacious

In this Series paper, we review the causes, burden, and consequences of iron deficiency anaemia in the general population of sub-Saharan Africa, as well as current policies and interventions for its control.