ABSTRACT
Iodine is a trace element required in minute quantities for proper growth and development of human brain and body. Iodine deficiency is now recognized by World Health Organization as the most preventable cause of brain damage in the world. The study assessed the iodine status and academic performance of school aged children in Umuahia North Local Government Area, Abia State. Urine samples were obtained from 130 children, 70 males and 60 females. Background and socio-economic information, food consumption pattern and academic performance were all studied using validated questionnaire. Urinary iodine concentration analysis, using Sandell-Kolthoff reaction was used to determine the iodine status of the children while the average of a session’s result was used to assess their academic performance. Background information of the children showed that 39.2% of the children were 6-7 years, 34.0% were 8-9 years, 23.1% were 10-11 years, while 3.8% were 12 years. All the respondents claimed that they have heard about iodized salt, 1.8% claimed they heard about iodized salt from their friends, 50.8% heard about iodized salt at the market, 3.8% heard it from their relatives while 34.6% heard about iodized salt from the media (TV and Radio). Majority of the respondents (91.5%) claimed they consume iodized salt while 8.5% said they use salts that are measured in cups which is not iodized salt. The study indicated that 6.9% had moderate iodine deficiency, 24.6% had mild iodine deficiency, 50.8% had optimal status while 17.7% had more than adequate iodine sufficiency. For academic performance scores, 31.5% scored average, 47.0% above average, 21.5% scored excellent, while none of them had scores below average. The frequency of consumption of iodized salt showed that 91.5% of respondents consumed iodized salt at least once a day. Chi-square analysis was done to determine the relationship between academic performance and iodine status among male and female children, and there was a significant relationship (P <0.05). The relationship between socio economic variables and iodine status showed that gender, fathers’ income and mothers’ education had no significant relationship with iodine status (p> 0.05) while mothers’ income and fathers’ education had a significant relationship with iodine status (p< 0.05). Nutrition education should be aimed at mothers, caregivers, and school children to promote consumption of iodine rich foods.
TABLE OF CONTENTS
Title page i
Certification ii
Dedication iii
Acknowledgement iv
Table of content v
List of tables vii
Abstract viii
CHAPTER 1
INTRODUCTION 1
1.1 Statement of problem 4
1.2 Objectives of the study 8
1.3 Significance of study 8
CHAPTER 2
LITERATURE REVIEW 10
2.1 Iodine 10
2.1.1 Historical background of iodine 10
2.1.2 Dietary sources of iodine 11
2.1.3 Recommended dietary allowance (RDA) of iodine 12
2.2 School age children 13
2.3 Academic performance 14
2.3.1 Iodine and cognitive performanc 15
2.4 Iodine deficiency disorder and causes 17
2.4.1 Lack of dietary iodine 18
2.4.2 Mal-absorption of iodine 19
2.4.3 Drug nutrient interaction 20
2.5 Types of iodine deficiency disorders 20
2.5.1 Goitre 21
2.5.2 Cretinism 22
2.5.2.1 Neurological cretinism 23
2.5.2.2 Myxoedematous cretinism 23
2.5.3 Hypothyroidism 23
2.5.4 Impaired mental function 24
2.6 Prevalence of iodine deficiency disorder 24
2.7 Absorption and metabolism of iodine 26
2.8 Toxicity of iodine 28
2.9 Functions of iodine 29
2.9.1 Iodine in mental development 30
2.10 Methods of assessing iodine status 31
2.10.1 Urinary iodine concentration method 31
2.10.2 Goitre rate or thyroid size 34
2.10.3 Serum thyroglobulin 35
2.10.4 Thyroid stimulating hormone concentration 35
2.11 Treatment and prevention of iodine deficiency 36
2.11.1 Salt fortification with iodine 36
2.11.2 Iodized oil 36
2.11.3 Iodized water 36
CHAPTER 3
MATERIALS AND METHODS 37
3.1 Study design 37
3.2 Study area 37
3.3 Population of the study 38
3.4 Sampling and sampling procedure 38
3.4.1 Sample size 38
3.4.2 Sampling procedure 39
3.5 Preliminary activities 40
3.5.1 Preliminary visits 40
3.5.2 Training of research assistants 40
3.5.3 Ethical approval 40
3.5.4 Informed consent 40
3.6 Data collection 41
3.6.1 Questionnaire administration 41
3.6.2 Biochemical analysis of iodine 41
3.6.3 Equipment used 42
Academic performance determination 43
Statistical analysis 43
CHAPTER 4
RESULTS AND DISCUSSION 45
CHAPTER 5
CONCLUSION 64
5.1 Conclusion 64
5.2 Recommendations 65
References
Appendix
LIST OF TABLES
Table 2.1: RDA of iodine 12
Table 2.2: Iodine deficiency disorder at each stage of development 21
Table 2.3: Prevalence of goitre and low urinary iodine in Africa 25
Table 2.4: Total goitre rate in selected LGA in Nigeria 26
Table 2.5: WHO criteria for assessment of iodine nutrition
through population based median urinary iodine
concentration (UIC) 34
Table 4.1: Personal information of the children 46
Table 4.2: Socio economic information of the respondents 48
Table 4.3: Information on knowledge and use of iodized salt 50
Table 4.4: Urinary iodine status of the children 53
Table 4.5: Academic performance of the children 55
Table 4.6: Food consumption pattern of the children using Food
Frequency Questionnaire, with emphasis on iodine
rich foods and iodized salt 57
Table 4.7: Cross-tabulation of iodine status and socio-economic
variables. 60
Table 4.8: Cross-tabulation of iodine status and academic
performance of the children 63
CHAPTER 1
INTRODUCTION
Iodine is a trace element required in minute quantities by our body (Shubhangini, 2002). It is required essentially for normal growth and development of human brain and body (Srilakshmi, 2011). It is needed for the production of thyroid hormone (Triiodothyronine (T3) and Thyroxine (T4) which are necessary for the development of brain during foetal development, post natal life and for proper functioning of the body (Okoli, 2009). Good brain development is of importance for other body functions thus children need iodine to maintain bodily growth and functions (Okoli, 2009). Iodine deficiency during early foetal life can adversely affect neurological development causing impaired cognitive functions or learning disabilities of varying degrees, hearing deficits, diverse illnesses and death (Zimmermann, 2009). Iodine deficiency is now recognized by World Health Organization as the most preventable cause of brain damage in the world today
(Srilaskshmi, 2011). It is a major global public health problem and it affects about 15% of the world’s population as at 2011. Moreover, about one third of school children worldwide have insufficient iodine intake (Srilaskhmi, 2011). Iodine deficiency disorders are found among children, adolescents, pregnant women and young adults living in hilly mountainous areas where the soil has been leached of iodine, either due to flooding of river valley or by high rainfall or glaciations (Delange, 2000). In Africa, surveys carried out within 1995-2007 showed prevalence (in percentage) of goitre and with West Africa having 15.7 and 12.9 percents in 1995-2000 and 2001-2007 respectively.
Iodine Deficiency Disorder (IDD) is a major global cause of morbidity, mortality and impaired development in children (Madukosiri, 2011). It has substantial effects on growth and development and is the most common cause of preventable mental impairment worldwide. Mild iodine deficiency impairs cognition in children, and moderate to severe iodine deficiency in a population, reduces intelligent quotient (IQ) by 10-15 points thereby leading to poor academic performance in school (Zimmermann, 2009). Academic performance is the outcome of education, that is, the extent to which a student, teacher or institution has achieved their educational goals. It is commonly measured by examination or continuous assessments but there is no general agreement on how it is best tested or which aspect are most important- procedural knowledge such as skills or declarative knowledge such as facts (Annie et al., 1996). Iodine deficiency still constitutes the single greatest cause of preventable brain damage and mental retardation, which in turn makes the child not to attain optimal performance; despite the teaching he gets (Delange, 2000).
All degrees of iodine deficiency affect the thyroid function of the neonate, and the mental development of the child (Delange, 2000). The resulting mental deficiency has an immediate effect on child learning capacity, the quality of life of communities and economic production (WHO, 2011). Other consequences of iodine deficiency and subsequent inadequate thyroid hormone production include goitre, hypothyroidism, cretinism, congenital anomalies, increased prenatal mortality, still births and abortions. Much has been achieved in the area of universal salt iodization in the sub-Saharan Africa and Nigeria in particular (UNICEF, 2003). Nevertheless iodine deficiency continues to be of public health importance in some communities (SCN, 2004). There are high cases of iodine deficiency disorders in zones located in isolated places or high mountains far from the sea (Holowell et al., 1994). Iodine is very necessary in foetal development, as it aids in formation of thyroid hormones which are necessary for proper brain development. The link between prenatal iodine deficiency and cognitive development is direct, as maternal iodine sufficiency means the foetus has stores of iodine from which the brain draws up iodine during development, which aids in academic performance in later years of life especially during school age (Delange, 2000).
Four different methods are generally recommended for the assessment of iodine nutrition in populations; urinary iodine concentration (UIC), goitre rate, thyroid stimulating hormone and serum thyroglobulin (Zimmermann, 2009). These indicators are complementary, in that urinary iodine is a sensitive indicator of recent iodine intakes (days) and blood/serum thyroglobulin shows an intermediate response (weeks to months) whereas changes in the goitre rate reflects/indicates long term iodine status (months to years) (Haldimann, 2005).
Fortification and consumption of locally available sources of iodine rich food are useful steps that have influenced the quality of food, processing and storage and improved education on consumers, which have helped to adopt better preparation practices (Okoli, 2009). People in deficient areas can receive iodine as an additive to food or water or by direct administration of iodized oil or potassium iodide or iodine in Lugols solution. Iodine is found in sea foods naturally and the extent to which it is found in foods depends largely on the iodine content of the environment’s soil and water (Hollowell et al., 1994). This study is an attempt to assess the Iodine status and academic performance of school age children in Umuahia North local government area in Abia State.
1.1 STATEMENT OF PROBLEM
Micronutrients deficiencies are frequently superimposed on the other form of deficiencies, rarely occurring in isolation and reflecting poor diet quality (Scrimshaw, 1994). It usually has devastating impacts on foetal growth, health and development of school children of all ages. Supply of diverse diet has become a rare thing in our society today, most times because of lack of knowledge on the part of mothers and caregivers. Iodine deficiency being a major public health concern, apart from arising from iodine leached-out soil and iodine poor water supply, can also be attributed to monotony in diet and high rising love for processed foods (Bwibo and Newmann, 2003). Iodine deficiency disorders (IDD) is a serious public health problem in developing countries. It is one of the oldest and most insidious of human health problems. WHO. (2011) estimated that two billion people worldwide including 285 million children of school age have iodine deficiency despite major national and international efforts to increase iodine intake, mainly through voluntary or mandatory intake of iodized salt (WHO, 2011). Recent estimates by the World Health Organization indicates that 54 countries are still affected by iodine deficiency and nearly 2 billion individuals worldwide are iodine-deficient. A large percentage of the world population is at risk of iodine deficiency disorder (IDD) (Delange, 2000). Poor nutrition remains a global epidemic, contributing to more than half of all children’s mortality, about 5.6 million per year. It has been reported that as severity of iodine deficiency increases, the occurrence of poor pregnancy outcome such as miscarriage, still birth, and increased infant mortality is more likely (Bruno and Maria, 2004).
Several parts of Nigeria have been identified with goitre endemicity and labeled the “goitre belt” (Abua et al., 2008). In 1993, a National goitre rate of 20% was reported and 20 million Nigerians were estimated to be affected by IDD (UNICEF, 1993). The Participatory Information Collection Study (1993), using thyroid hormone concentrations as indicators of iodine status reported an iodine deficiency prevalence of 65.6% in south-east, 41% in south-west, and 43% in the north-west of Nigeria. Less than a decade later, national survey showed that goitre prevalence among 30 states in Nigeria dropped from 40 million in 1990 to less than 11 million in 1999 (IDD Newsletter, 2000). There has been several intervention initiatives rolled out by the government and other international agencies, to combat the menace of IDD in Nigeria (Madukosiri, 2011). Devastating outcomes for central nervous system are particularly due to maternal iodine deficiency. Foetal iodine deficiency is caused by iodine deficiency in mother during pregnancy. Before the foetal thyroid gland becomes functional at 16- 20 weeks gestation, maternal thyroxine (T4) crosses the placenta to promote normal embryonic and foetal development. Hence, maternal iodine deficiency can result in hypothyroidism in the offspring, which in chronic cases, depending on the timing, may lead to cretinism-a condition associated with irreversible mental retardation and brain damage and if not given iodine rich foods during the first 3 years of life may have low academic outcomes. Although small amounts of iodine are naturally present in soil, water, plants and animals, most of the iodine in soil has been lost through erosion, run-off and vaporization over the years leading to insufficient dietary intake or naturally occurring iodine (WHO, 2004).
Goitrogens in the diet such as cyanides in cassava and other compounds in maize, millet and cabbage block the uptake of iodine by the thyroid which could lead to disorders like low brain development, mental retardation, deaf mutism and spastic diplegia, cretinism, hypothyroidism, impaired physical development, increased prenatal and infant mortality, poor academic performance, goitre, etc (WHO, 2004). In relation to this, WHO estimates that iodine deficiency may reduce a child’s mental development by 10% and may make iodine deficient people forfeit at least 15 intelligent quotient points (WHO, 2004). Estimates based on urinary iodine levels indicates that 35% of the world population is affected by iodine deficiency disorder with about 10-57% in Europe, Africa and South East Asia (WHO, 2004). While iodine deficiency is known to cause endemic goitre, its most deleterious effect is on brain dysfunction to irreversible intellectual impairment (Boyages and Guttikonda, 2009). This study is an attempt to assess the iodine status and academic performance of school age children in Umuahia North Local Government Area, Abia State.
1.2 OBJECTIVES OF THE STUDY
General objective:
To assess the iodine status and academic performance of school age children (6-12 years) in Umuahia North local government area.
Specific objectives are to:
1) Determine the iodine status of school age children using biochemical method.
2) Assess the Academic performance of school age children.
3) Determine the relationship between Iodine deficiency and Academic performance of the children studied.
4) Ascertain level of consumption of iodized salt and iodine rich foods.
5) Compare the prevalence of iodine deficiency and academic performance between males and females.
1.3 SIGNIFICANCE OF STUDY
This research’s findings will provide information on the usefulness of the dietary sources of iodine and iodized salt. Caregivers will be enlightened on the dangers of iodine deficiency and the effects it has on the child’s academic performance and on the body. The study can help in developing a concerted school food service by the government and school authorities, to help increase the intake of iodine rich foods. Again, the study can help in educating the general public on developing good dietary habits via consumption of locally available iodine rich foods. The study can help the health authorities in planning and programming of supplementation activities. The information should also be useful to all agencies with primary and secondary mandates with a focus on nutrition. Finally, the study can help in reducing morbidity and mortality among the school age children through supplementation with iodine where necessary. The study will provide a way out on the prevention and treatment of iodine deficiency disorders.
Login To Comment