Anaemia

What does this indicator tell us?

The indicator anaemia has a wide variety of causes. Iron deficiency is considered to be the most common cause of anaemia; other causes include acute and chronic infections that result in inflammation and blood loss; deficiencies of other vitamins and minerals, especially folate, vitamin B12 and vitamin A; and genetically inherited traits, such as thalassaemia. Other conditions (e.g. malaria and other infections, genetic disorders, and cancer) can also play a role in anaemia. The terms “iron-deficiency anaemia” and “anaemia” are often used synonymously; also, the prevalence of anaemia has often been used as a proxy for iron-deficiency anaemia, although the degree of overlap between the two varies considerably from one population to another, according to gender and age.

Anaemia prevalence among pregnant and non-pregnant women are included as primary outcome indicators in the core set of indicators for the Global Nutrition Monitoring Framework. These indicators are used to monitor progress towards achieving Global Nutrition Target 2, which is a 50% reduction in anaemia among women of reproductive age by 2025. Anaemia in women of reproductive age and in children are also included in the WHO Global reference list of 100 core health indicators.

How is it defined?

Anaemia is defined as a haemoglobin concentration below a specified cut-off point; that cut-off point depends on the age, gender, physiological status, smoking habits and altitude at which the population being assessed lives. WHO defines anaemia in children aged under 5 years and pregnant women as a haemoglobin concentration <110 g/L at sea level, and anaemia in non-pregnant women as a haemoglobin concentration <120 g/L.

Tests to measure haemoglobin levels are easy to administer. A few drops of blood obtained by a finger-stick can be used to assess haemoglobin concentrations in the field using a portable haemoglobinometer. The test could be easily integrated into regular health or prenatal visits or household surveys, to capture women of reproductive age, although the cost of the equipment and regular calibration needs to be taken into account.

What are the consequences and implications?

Anaemia is associated with increased risks for maternal and child mortality. Iron-deficiency anaemia reduces the work capacity of individuals and entire populations, with serious consequences for the economy and national development. In addition, the negative consequences of iron-deficiency anaemia on the cognitive and physical development of children and on physical performance – particularly the work productivity of adults – are major concerns. Anaemia is a global problem affecting all countries. Resource-poor areas are often more heavily affected because of the prevalence of infectious diseases. Malaria, HIV/AIDS, hookworm infestation, schistosomiasis and other infections such as tuberculosis contribute to the high prevalence of anaemia in some areas.

The main risk factors for iron-deficiency anaemia include a low dietary intake of iron or poor absorption of iron from diets rich in phytates or phenolic compounds. Population groups with greater iron requirements, such as growing children and pregnant women, are particularly at risk. Overall, the most vulnerable, poorest and least educated groups are disproportionately affected by iron-deficiency anaemia.

Cut-off values for public health significance

Reference: WHO, 2008.

Source of data

WHO. Global Health Observatory (GHO) data repository.

Prevalence of anaemia in women of reproductive age. Estimates by country (https://apps.who.int/gho/data/node.main.ANEMIA3?lang=en)

Prevalence of anaemia in pregnant women. Estimates by country. (http://apps.who.int/gho/data/view.main.ANAEMIAWOMENPWv).

Prevalence of anaemia in non-pregnant women. Estimates by country (http://apps.who.int/gho/data/view.main.ANAEMIAWOMENNPWv). 

Further reading

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 Global Health. 2013;1:e16-25.

WHO. Global nutrition targets 2025: anaemia policy brief. Geneva: World Health Organization; 2014 (http://who.int/nutrition/publications/globaltargets2025_policybrief_anaemia/en/).

WHO. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Vitamin and Mineral Nutrition Information System. WHO/NMH/NHD/MNM/11.1. Geneva: World Health Organization; 2011 (http://www.who.int/vmnis/indicators/haemoglobin.pdf).

WHO, UNICEF. Global Nutrition Monitoring Framework: operational guidance for tracking progress in meeting targets for 2025. Geneva: World Health Organization; 2017 (http://www.who.int/nutrition/publications/operational-guidance-GNMF-indicators/en/).

WHO. Global reference list of 100 core health indicators (plus health-related SDGs). Geneva: World Health Organization; 2018 (https://www.who.int/healthinfo/indicators/2018/en/).

Internet resources

WHO. Vitamin and Mineral Nutrition Information System (VMNIS). (http://www.who.int/vmnis/en/).

WHO. Anaemia/iron deficiency list of publications. (http://www.who.int/nutrition/publications/

micronutrients/anaemia_iron_deficiency/en/index.html).

WHO. e-Library of Evidence for Nutrition Actions (eLENA). Health conditions. Anaemia (http://www.who.int/elena/health_condition/en/#anaemia).

WHO. e-Library of Evidence for Nutrition Actions (eLENA). Interventions by global target (http://www.who.int/elena/global-targets/en):

Target 2: 50% reduction of anaemia in women of reproductive age (http://www.who.int/elena/global-targets/en/#anaemia).