ANAEMIA

This is a reflection of an inadequate number of red blood cells or an insufficient amount of haemoglobin (Hb) in the blood. Children aged 5–11 years are considered to be anaemic when the Hb concentration is below 115 g/litre and severely anaemic when it is below 80 g/litre.

Children aged 12–14 years are considered to be anaemic when the Hb concentration is below 120 g/litre and severely anaemic when it is below 80 g/litre.²

66 Anaemia is a specific condition where red blood cells are not providing adequate oxygen to the body tissues. It is usually caused by iron deficiency, which is the commonest micronutrient deficiency in both developing and developed countries.^{26, 241} Generally, it takes at least several weeks after iron store has depleted before anaemia develops. When iron deficiency occurs, haemoglobin concentrations are reduced to below optimal levels and therefore, iron deficiency anaemia (IDA) is considered to be present. However, because anaemia is the most common indicator used to screen for iron deficiency, the terms anaemia, iron deficiency, and IDA are sometimes used interchangeably and synonymously.²⁴⁰

Most affected group include pregnant women, pre-school and school-age children, low birth weight infants and women of child-bearing age.²⁶

4.1 Prevalence of Anaemia

Globally, anaemia affects 1.62 billion people (95% CI: 1.50–1.74 billion), which corresponds to 24.8% of the population (95% CI: 22.9–26.7%).²⁶ The highest prevalence is in preschool-age children (47.4%, 95% CI: 45.7–49.1), and the lowest prevalence is in men (12.7%, 95%

CI: 8.6–16.9%).Prevalence in school age children is 25.4% (95% CI: 19.9 – 30.9), affecting 305 million children in this age group.²⁶

The majority of the global disease burden of anaemia is shouldered by the developing world though developed countries are also affected, with prevalence in Africa and South East Asia as high as two thirds among children under five, and nearly half among women.²⁶WHO regional estimates generated for preschool-age children, pregnant and non-pregnant women indicate that the highest proportion of individuals affected are in Africa (47.5–67.6%), while the greatest number affected are in South-East Asia where 315 million (95% CI: 291–340) individuals in these three population groups are affected²⁶, and WHO has classified anaemia as a severe

67 public health problem (prevalence ≥ 40%) for children under five in 69 countries, and for pregnant women in 68 countries.²⁶

In Bangalore, South India, blood Hb concentration of all children was 12.6+/-1.1 g/dl (range 5.6-16.7). The overall anaemia prevalence in this group was 13.6% and there was no significant difference in anaemia prevalence between children in urban and rural locations (14.6 and 12.3%, respectively).²⁴² A study in Palestine showed that anaemia constitute a health problem in Gaza with a prevalence of 35.3%. There was no variation in the prevalence of anaemia among the three areas studied. It was concluded that anaemia still constitutes a health problem among schoolchildren.²⁴³ In India, among school children; prevalence of anaemia using the WHO recommended cut off value of haemoglobin was 52.88%.²⁴⁴

Studies have also shown low iron status and iron deficiency anaemia to be prevalent in African populations. A study of 8 African and Asian countries found that 40%-60% of school aged children in Mali, Tanzania, Mozambique, Ghana, Malawi and Kenya and 12% and 30% of those in Vietnam and Indonesia suffered anaemia.²⁴⁵

In Nigeria, a study among children in three rural communities of Ovia North East Local Government Area reported that of a total of 316 children between the ages of 1 and 15 years that were included in the study, 38.6% were anaemic, having haemoglobin levels lower than the 11g/dl.²⁴⁶ It was also reported in two rural areas of Odogbolu Local Government Area among pre-school and school age children that most of the children (87.1%) were anaemic having PCV values below the 32% cut-off and 95% with haemoglobin levels lower than 11 g/dl.²⁴⁷ In rural communities in Abia State among school age children, the results showed that the prevalence of anaemia was 82.6%.²⁴⁸

4.2 Risk factors for Anaemia in School Children

68 The risk factors for anaemia in school children are the same like those for nutritional status. In a study conducted in Tanzania, the risk of having anaemia was two times higher in children with iron deficiency (RR=2.1) and 49% higher in those with vitamin A deficiency.²⁴⁸ These deficiencies correlated significantly with the anaemia (P<0.05). Vitamin A deficiency and infections with hookworm and schistosomiasis were the most significant factors predicting for anaemia (r=0.318 and r2=0.101) and it was concluded that high prevalence of infections and nutritional deficiencies are important risk factors for anaemia.²⁴⁹

In a survey of students between 6 and 16 years in Morocco, there was a significant relationship between education of the mother and anaemia in children (p= 0.01).²⁵⁰ Another survey in Malaysia observed that iron deficiency was significantly higher in girls (p = 0.032) compared to boys.²⁵¹ Univariate analysis demonstrated that low level of mother's education (OR = 2.52; 95%

CI = 1.38-4.60; p = 0.002), non-working parents (OR = 2.18; 95% CI = 2.06-2.31; p = 0.013), low household income (OR = 2.02; 95% CI = 1.14-3.59; p = 0.015), T. trichiura (OR = 2.15; 95%

CI = 1.21-3.81; p = 0.008) and A. lumbricoides infections (OR = 1.63; 95% CI = 1.04-2.55;

p = 0.032) were significantly associated with the high prevalence of Iron deficiency anaemia.

Multivariate analysis confirmed that low level of mother's education (OR = 1.48; 95 CI% = 1.33-2.58; p<0.001) was a significant predictor for IDA in these children.²⁵¹

In the assessment of anaemia in 208 school age children between 7 and 12 years in rural communities of Abia State, Nigeria, it was found that anaemia was significantly associated with helminth infestation, malaria parasite and C-Reactive Protein.²⁴⁸

4.3 Diagnosis of anaemia

4.3.1 Clinical examination

69 Physical examination can be used for diagnosing anaemia and this aims to identify skin or mucous membrane pallor as clinical signs of anaemia. Anatomical segments such as the conjunctiva, palm, nail bed, lips and tongue have been used to identify anaemia.^{241, 252}

Due to the need for intervention in high infant morbidity and mortality rates, especially in developing countries, the Pan-American Health Organization (PAHO), World Health Organization and the United Nations Children's Fund (UNICEF) formulated Guidelines for Integrated Management of Childhood Illness (IMCI), which guide the evaluation and classification of anaemia in children based on the clinical signs of light or severe palmar pallor.²⁵³

4.3.2 Laboratory method

Haemoglobin analysis is one simple and most economical laboratory parameter and is thus used quite frequently in population studies. The diagnostic criteria for anaemia was defined by WHO as a haemoglobin concentration less than 12 g/L.²⁴¹ There are different laboratory methods and they include the following:

4.3.2.1 Direct cyanmethaemoglobin measurement: This is the gold standard for assessing haemoglobin concentration.²⁵⁴ To avoid inter-laboratory variability, it is necessary that all measurements are conducted by the same laboratory.²⁵⁵

4.3.2.2 Indirect measurement of cyanmethaemoglobin: This indirect method, significantly overestimates the prevalence of anaemia, probably because some blood remains on the filter paper after the dissolving process.²⁵⁵ If the method is used for studies of anaemia prevalence, it can produce misleading results ²⁵⁶, and is therefore not suitable as an NTD monitoring tool.

4.3.2.3 HemoCue method: This is a method that uses a new generation of haemoglobin photometer, the HemoCue. It is the method that has been most widely used in field situations in NTD programmes.^{62, 257} It is a small battery-operated machine which produces a direct read-out

70 of haemoglobin to one decimal place in a few seconds, using a drop of blood in a plastic cuvette. In routine practice and large field surveys it gives consistent results ²⁵⁶, and is very user-friendly.

4.3.2.4 Haemoglobin colour scale: Stott and Lewis developed a new and alternative method, the WHO haemoglobin colour scale. Initially, the technique involved the comparison of a blood drop collected on a piece of special filter paper with a colour scale including ten shades of red.²⁵⁸ Later on, scales were developed with six shades of red and various studies have been carried out to verify their performance.^259-261

5 RELATIONSHIP BETWEEN SOIL – TRANSMITTED