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118 Pages·2014·1.93 MB·English

Vitamin A Status and Associated Factors Among Preschool Children Aged
3 to 5 Years in Offa District, Southern Ethiopia

Rediet Abebe

Thesis Submitted to School of Graduate Studies of Addis Ababa University
in Partial Fulfillment of the Requirements for the Degree of Master of
Science in Medical Physiology

Principal Advisor: Prof. Yekoye Abebe
Co- Advisor: Tesfaye Hailu (MSc)

August, 2017
Department of Physiology
College of Health Sciences
Addis Ababa University

Vitamin A Status and Associated Factors Among Preschool Children Aged 3 to
5 Years in Offa District, Southern Ethiopia
By
Rediet Abebe

Approval by Examining Board

Professor Yekoye Abebe ________________
Advisor
Dr. Wondyefraw Mekonen ________________
Examiner
Dr. Tesfaye Tolessa ________________
Head, Department of Physiology
Acknowledgments
I would like to thank the almighty God who gave me the opportunity and strength for
accomplishment of my thesis.
I express my heartfelt gratitude to my advisor Professor YekoyeAbebe and Co advisor Mr.
Tesfaye Hailu for their valuable advices and constructive comments throughout the
preparation of the thesis.
My deepest gratitude also goes to Addis Ababa University, College of Health Sciencesand
School of Medicine, Department of Physiology for giving me this great opportunity.
My sincere thanks also goes to Dr. Nigusse Deyessa and Beza Teshome for their assistance
on statistical analysis.
I am grateful to Ethiopian Public Health Institute, Food Science and Nutrition Directorate for
their financial, laboratory equipment and reagents support. My acknowledgement also goes to
my family and friends for their unreserved support.
I also thank the Research and Publication office, Addis Ababa University for the financial
support and Wolaita Sodo University for sponsoring me during my post graduate training
program.

ii
Table of Contents
Acknowledgments ......................................................................................................................................... ii
Table of Contents ......................................................................................................................................... iii
List of Tables ................................................................................................................................................ v
List of Figures .............................................................................................................................................. vi
Abbreviations and Acronyms ..................................................................................................................... vii
Abstract ...................................................................................................................................................... viii
1. Introduction ............................................................................................................................................... 1
1.1 Background ......................................................................................................................................... 1
1.2 Burden of vitamin A deficiency .......................................................................................................... 2
1.3 Conceptual framework of vitamin A status ........................................................................................ 3
1.4 Control of vitamin A deficiency ......................................................................................................... 6
1.5 Statement of the problem .................................................................................................................... 7
1.6 Significance of the study ..................................................................................................................... 7
2. Literature review ....................................................................................................................................... 9
2.1 Historical background of vitamin A .................................................................................................... 9
2.2 Metabolism of vitamin A .................................................................................................................. 10
2.3 Functions of vitamin A ..................................................................................................................... 11
2.3.3 Immunity .................................................................................................................................... 11
2.3.1 Vision ......................................................................................................................................... 12
2.3.2 Maintain epithelial cells integrity .............................................................................................. 13
2.3.4 Growth ....................................................................................................................................... 13
2.3.5 Reproduction .............................................................................................................................. 13
2.3.6 Erythropoiesis ............................................................................................................................ 13
2.4 Recommended intake ........................................................................................................................ 14
2.5 Assessment of vitamin A .................................................................................................................. 14
3. Objectives ............................................................................................................................................... 16
4. Materials and methods ............................................................................................................................ 17
4.1 Study area.......................................................................................................................................... 17
4.2 Study design and study period .......................................................................................................... 17
4.3 Source population ............................................................................................................................. 17
4.4 Study population ............................................................................................................................... 18
4.5 Eligibility criteria .............................................................................................................................. 18
4.6 Sample size determination ................................................................................................................ 18
4.7 Sampling technique ........................................................................................................................... 18
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4.8 Study variables .................................................................................................................................. 19
4.8.1 Dependent variable .................................................................................................................... 19
4.8.2 Independent variables ................................................................................................................ 19
4.9 Operational Definitions ..................................................................................................................... 19
4.10 Data collection tools and procedures .............................................................................................. 20
4.10.1 Anthropometry ......................................................................................................................... 20
4.10.2 Food consumption .................................................................................................................... 21
4.10.3 Specimen collection ................................................................................................................. 21
4.10.4 Laboratory analysis .................................................................................................................. 21
4.11 Data quality control ......................................................................................................................... 23
4.12 Data processing and analysis .......................................................................................................... 23
4.13 Ethical considerations ..................................................................................................................... 23
4.14 Dissemination of findings ............................................................................................................... 24
5. Result ...................................................................................................................................................... 25
5.1 Socio demographic characteristics .................................................................................................... 25
5.2 Child health and nutrition related characteristics .............................................................................. 27
5.3 Prevalence of vitamin A deficiency .................................................................................................. 29
5.4 Risk factors for vitamin A deficiency ............................................................................................... 30
6. Discussion ............................................................................................................................................... 33
7. Conclusion .............................................................................................................................................. 36
8. Recommendation .................................................................................................................................... 37
9. Limitations .............................................................................................................................................. 38
10. References ............................................................................................................................................. 39
11. Annexes................................................................................................................................................. 42

iv
List of Tables
Table 1: Global prevalence of night blindness, serum retinol concentrations <0.70 µmol/l and
number of individuals affected in populations of countries at risk of vitamin A deficiency 1995-
2005(5). ......................................................................................................................................................... 2
Table 2: Socio demographic characteristics of households and study participants in Offa
District, Wolaita Zone, Southern Ethiopia, 2017. .................................................................................. 26
Table 3: Health and nutrition related characteristics of study participants, Offa District,
Wolaita Zone, Southern Ethiopia, 2017. ................................................................................................. 28
Table 4: Blood vitamin A level (µmol/L) by age group and gender among study participants,
Offa District,Wolaita Zone, Southern Ethiopia, 2017. .......................................................................... 29
Table 5: Bivariate analysis showing factors associated with vitamin A deficiency among
preschool children, Offa District,Wolaita Zone, Southern Ethiopia, 2017. ......................................... 31
Table 6: Adjusted logistic regression for vitamin A deficiency and selected variables, Offa
District, Southern Ethiopia, 2017. ........................................................................................................... 32

v
List of Figures
Figure 1: Conceptual framework of vitamin A ............................................................................................. 5
Figure 2: Schematic representation of vitamin A metabolism. ................................................................... 11
Figure 3: Map of Offa woreda .................................................................................................................... 17
Figure 4: Schematic presentation of sampling procedure. .......................................................................... 19
Figure 5: Proportion of children 3-5 years old who consumed food groups in the previous 24 hour
preceding the survey, Offa District, Wolaita Zone, Southern Ethiopia, 2017. ........................................... 27
Figure 6: Prevalence of vitamin A deficiency among preschool children, Offa District, Wolaita Zone,
Southern Ethiopia, 2017. ............................................................................................................................. 30

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Abbreviations and Acronyms
AGP Alpha- 1- Acid Glycoprotein
APP Acute Phase Proteins
CRP C - Reactive Protein
CI Confidence Interval
EPHI Ethiopian Public Health Institute
HAZ Height for Age,Z-score
Hb Hemoglobin
HH Household
HPLC High Performance Liquid Chromatography
IVACG International Vitamin A Consultative Group
MDD Minimum Dietary Diversity
RBP Retinol Binding Protein
RDA Recommended Dietary Allowance
RDT Rapid Diagnostic Test
VAD Vitamin A Deficiency
VAS Vitamin A Supplementation
WAZ Weight for Age,Z-score
WHZ Weight for Height,Z-score

vii
Abstract
Background: Vitamin A is a vital micronutrient involved in several biochemical activities
crucial for regular biological purpose. Vitamin A Deficiency (VAD) is a common form of
micronutrient deficiency. Globally about 30% of children <5 years of age are vitamin A
deficient and about 2% of all deaths are attributable to VAD in this age group. The aim of
this study was to assess vitamin A status and associated factors among preschool children (3-
5 years) in Offa District, Southern Ethiopia.
Method: Community based cross sectional study was conducted from October to November
2016. Structured interviewer administered questionnaire adapted from relevant studies was
used. Four kebeles were selected randomly from Offa District for the study. A total of 204
children aged 36 to 59 months were included for socio demographic, 24 hour dietary recall
and anthropometry measurements. Biochemical analysis was performed for serum retinol and
hemoglobin concentrations. Malaria and stool examinations were also assessed. Statistical
significance was interpreted using adjusted odds ratio (AOR) with 95% confidence interval
with p- value <0.05.
Result: The prevalence of vitamin A deficiency was 32.7% with mean serum retinol level of
0.87±0.33 μmol/l. Seventy nine percent of the children received vitamin A supplementation
in the previous six months. Moderate anemia (Hb 7- 9.9 g/dl) affected about 10 (9%) children
and 9% of the children had diarrhea in previous two weeks. Minimum dietary diversity of the
children was 19.6%. The prevalence of intestinal parasites was about 4%. The multivariate
analysis showed a statistically significant association of vitamin A deficiency with anemia
[AOR=5.2; P<0.05], source of drinking water [AOR=4.8;P<0.05) and sanitation facility
[AOR=0.04;P<0.05).
Conclusion: Vitamin A deficiency is a severe public health problem in the study area. This
may be due to low intake of vitamin A rich diet. In addition, high prevalence of stunting and
inflammation also contributes to the problem.
Key words: Vitamin A, Determinants, Preschool children
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1. Introduction
1.1 Background
Vitamin A is a vital micronutrient involved in several biochemical activities crucial for
regular biological purpose. Vitamin A and its metabolites play diverse role in physiology,
ranging from incorporation into vision pigments to controlling transcription of important
genes (1,2). It is commonly known as anti-infective vitamin, because it is required for normal
functioning of the immune system, for regulation of cell mediated immunity and humoral
antibody responses. Retinol and its metabolites are required to maintain the integrity and
function of skin and mucosal cells which function as a barrier and form body's first line of
defense against infection (1,3).
VAD is state of inadequate vitamin A nutriture. It begins when liver stores of vitamin A fall
below 0.07µmol/g, serum retinol levels may still be within the homeostatically regulated
normal range(4). The World Health Organization defines vitamin A deficiency as tissue
concentrations of vitamin A low enough to have adverse health consequences, even if there is
no evidence of clinical deficiency (5). It occurs when body stores are depleted to the extent
that physiological functions are impaired even though clinical eye signs may not be evident
(5).
According to the recommended cut off points, serum retinol concentrations below
0.70μmol/L indicate vitamin A deficiency and concentrations between 0.70 and 1.05μmol/L
indicate marginal deficiency. Vitamin A deficiency can be characterized as a severe,
moderate and mild public health problem; when the plasma retinol concentration is below
0.70 μmol/l in ≥ 20%, 10% to 19% and 2% to 9% of the target population, respectively (5, 6).
There are a lot of disorders that occur following deficiency of vitamin A, collectively known
as vitamin A deficiency disorders (VADD). VADD are defined as any health and physiologic
consequences attributable to vitamin A deficiency, whether clinically evident (xerophthalmia,
anemia, growth retardation, increased infectious morbidity and mortality) or subclinical
(impaired iron mobilization, disturbed cellular differentiation and depressed immune
response) (4). Low vitamin A intake during nutritionally demanding periods in life such as
infancy, childhood, pregnancy and lactation greatly raises the risk of health consequences or
vitamin A deficiency disorders (5).
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