Anaemia is common throughout the world. Its main cause, iron deficiency, is the most prevalent nutritional deficiency in the world. Several infections related to hygiene, sanitation, safe water and water management are significant contributors to anaemia in addition to iron deficiency. These include malaria, schistosomiasis and hookworm.
The disease and how it affects people
Anaemia is a condition that occurs when the red blood cells do not carry enough oxygen to the tissues of the body. Anaemia affects all population groups. However the most susceptible groups are pregnant women and young children. In the milder form, anaemia is “silent”, without symptoms. In the more severe form, anaemia is associated with fatigue, weakness, dizziness and drowsiness. The signs include loss of normal colour in the skin (in fair skinned people) and also in the lips, tongue nail beds and the blood vessels in the white of the eye. Without treatment, anaemia can worsen and become an underlying cause of chronic ill health, such as impaired fetal development during pregnancy, delayed cognitive development and increased risk of infection in young children, and reduced physical capacity in all people. Low birth weight infants, young children and women of childbearing age are particularly at risk of anaemia. Women of childbearing age need to absorb 2-3 times the amount of iron required by men or older women.
The main causes of anaemia are nutritional and infectious. They usually coexist in the same individual and make anaemia worst.
Among the nutrition factors contributing to anaemia, the most common one is iron deficiency. It is due to a diet that is monotonous, but rich in substances (phytates) inhibiting iron absorption so that dietary iron cannot be utilised by the body. Iron deficiency may also be aggravated by poor nutritional status, especially when it is associated with deficiencies in folic acid, vitamin A or B12, as is often the case in populations living in developing countries
With regard to infections, malaria is another major cause of anaemia : it affects 300-500 million people, and in endemic areas it may be the primary cause of half of all severe anaemia cases (WHO, 2000). Hookworm infection and in some places schistosomiasis also contribute to anaemia. Approximately 44 million pregnant women have hookworm infections and 20 million people are severely infected with schistosomiasis. Anaemia can also be due to excessive blood loss, such as gastrointestinal infections associated with diarrhoea. The most important water-related causes of anaemia are malnutrition and water-borne or water-related infections.
Anaemia is a common problem throughout the world and iron deficiency is the most prevalent nutritional deficiency in the world. It affects mainly the poorest segment of the population, particularly where malnutrition is predominant and the population exposed to a high risk of water-related infection.
Scope of the problem
Nine out of ten anaemia sufferers live in developing countries, about 2 billion people suffer from anaemia and an even larger number of people present iron deficiency (WHO, 2000). Anaemia may contribute to up to 20% of maternal deaths.
Full discussion of strategies towards anaemia prevention are beyond the scope of this Fact Sheet. Because anaemia is the result of multiple factors, the identification of these factors and of the causes and type of anaemia is important. Important actions include addressing underlying causes correcting iron deficiency, treatment of underlying disease processes (in particular nutritional deficiencies - Folic acid, Vitamin A and B12).
In children, promoting breastfeeding and proper complementary foods are important in controlling anaemia.
Improving hygiene, sanitation and water supply; and improving water resource management to contribute to control of schistosomiasis and malaria where they occur are important contributory measures in prevention of anaemia.
Anaemia prevention and control
Anaemia is the world's second leading cause of disability and thus one of the most serious global public health problems. Anaemia affects over half of pre-school children and pregnant women in developing countries and at least 30-40% in industrialized countries. In poorer malaria endemic countries anaemia is one of the commonest preventable causes of death in children under 5 years and in pregnant women.
Reducing the burden of anaemia will make a major contribution to achieving several UN Millennium Development Goals. Since the greatest burden of anaemia falls on the most "hard-to-reach" individuals, any programme that aims to reduce anaemia will need to be accessible by these groups. Primary health care policies and pro¬grammes must be a cornerstone of health care systems. Interventions which have been shown to impact on anaemia include improving nutrition and iron status and treating helminth and malaria infections.
The WHO Anaemia Working Group first met in June 2000 to review the relationship between haemoglobin concentrations and clinically symptomatic anaemia, with particular focus on cut-off levels for blood donation. This is why the Secretariat of the Group has traditionally been housed in the Department of Essential Health Technologies.
The WHO/UNICEF statement on anaemia underlines its multifactorial aetiology; hence the Group is now represented by diverse WHO programmes that need to address the prevention and control of anaemia. Roll Back Malaria is exploring the use of haemoglobin levels as a marker of success of malaria control interventions.
Early detection of anaemia in pregnant women is reflected in the vision of the Making Pregnancy Safer initiative. HIV/AIDS guid elines state that a haemoglobin estimation and HIV test are the absolute minimum before anti-retroviral therapy, meaning that simple, reliable and affordable screening tools must be widely available if 3 million people are to receive ARVs by 2005.
One such tool is the Haemoglobin Colour Scale, now commercially available to assist remote settings in the detection and management of anaemia.