Prevalence and risk factors for anemia among female students of ethnic minorities in thai nguyen province, vietnam

PREVALENCE AND RISK FACTORS FOR ANEMIA
AMONG FEMALE STUDENTS OF ETHNIC MINORITIES
IN THAI NGUYEN PROVINCE, VIETNAM

MISS HOA THI HONG HANH

A THESIS FOR DEGREE OF MASTER OF SCIENCE
KHON KAEN UNIVERSITY
2018


PREVALENCE AND RISK FACTORS FOR ANEMIA
AMONG FEMALE STUDENTS OF ETHNIC MINORITIES
IN THAI NGUYEN PROVINCE, VIETNAM

MISS HOA THI HONG HANH

A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE
GRADUATED SCHOOL KHON KAEN UNIVERSITY
2018


THESIS APPROVAL
KHON KAEN UNIVERSITY
FOR
MASTER OF SCIENCE
IN MEDICAL SCIENCE

Thesis title: Prevalence and risk factors for anemia among female students of ethnic
minorities in Thai Nguyen province, Vietnam.

Author: Miss Hoa Thi Hong Hanh
Thesis Examination committee
Prof. Dr. Sastri

Saowakhontha

Chairperson

Assoc. Prof. Dr. Kanokwan

Sanchaisuriya

Member

Assist. Prof. Dr. Pattara

Sanchaisuriya

Member

Prof. Dr. Supan

Fucharoen

Member

Assoc. Prof. Goonnapa

Fucharoen

Member

Prof. Dr. Arunee

Jetsrisuparp

Member

Thesis Advisers
…………………………………………………. Advisor
(Assoc. Prof. Dr. Kanokwan Sanchaisuriya)
…………………………………………………. Co-Advisor
(Assist. Prof. Dr. Pattara Sanchaisuriya )
…………………………………………

…………………………………………………..

(Prof. Dr. Surasukdi Wongratanacheewin)

(Assoc. Prof. Dr. Patcharee Jearanaikoon)

Dean, Graduated School

Dean, Faculty of Associated medical Science

Copyright of Khon Kaen University


i

Hoa Thi Hong Hanh.
่
่ นชน
ความชุกและปั จจัยเสียงภาวะเลื
อดจางในนักศึกษาหญิงทีเป็
กลุ่มน้อยในจังหวด
ั ไทเหงียน ประเทศเวียดนาม
วิทยานิ พนธ ์ปริญญาวิทยาศาสตรมหาบัณฑิต
สาขาวิทยาศาสตร ์การแพทย ์ คณะเทคนิ คการแพทย ์ มหาวิยาลัยขอนแก่น
่ กษาวิทยานิ พนธ ์: รศ.ดร.กนกวรรณ แสนไชยุรยิ า
อาจารย ์ทีปรึ
่ กษาร่วม: ผศ.ดร.ภัทระ แสนไชยสุรยิ า
อาจารย ์ทีปรึ

บทคัดย่อ
ภ า ว ะ เ ลื อ ด จ า ง เ ป็ น ห นึ่ ง ใ น ปั ญ ห า สุ ข ภ า พ ข อ ง ช น ก ลุ่ ม น้ อ ย
ป ร ะ เ ท ศ เ วี ย ด น า ม เ ป็ น ป ร ะ เ ท ศ ที่ มี ช น ก ลุ่ ม น้ อ ย ม า ก ถึ ง ช น เ ผ่ 5 4 า ก า ร ศึ ก ษ า ค ร ั้ ง นี ้
่
่
มีวต
ั ถุประสงค ์เพือประเมิ
นความชุกและหาปัจจัยเสียงของการเกิ
ดภาวะเลือดจางในหญิงวัยเจริญพันธุ ์ชนกลุ่มน้อยในตอ
่ าลังศึกษา ณ มหาวิทยาลัยไทเหงียน จานวน
นเหนื อของประเทศ อาสาสมัครเป็ นนักศึกษาแพทย ์กลุ่มชาติพน
ั ธุ ์ต่างทีก
ร า ย ท า ก า ร เ ก็ บ ข ้ อ มู ล พื ้ น 2 7 5 ฐ า น ทั่ ว ไ ป แ ล ะ ข ้ อ มู ล สุ ข ภ า พ โ ด ย ก า ร สั ม ภ า ษ ณ์
้ น
และเก็ บตัวอย่างเลือดหลังจากอาสาสมัครลงนามในแบบคายินยอม ในเบืองต
้ ตัวอย่างเลือดทุกรายถูกนาไปตรวจ

complete blood count ณ
โ ร ง พ ย า บ า ล ป ร ะ จ า จั ง ห วั ด ไ ท เ ห งี ย น
เ พื่ อ คั ด ตั ว อ ย่ า ง เ ลื อ ด ที่ ต ร ว จ พ บ ภ า ว ะ เ ลื อ ด จ า ง ไ ป ต ร ว จ วั ด ร ะ ดั บ เ ฟ อ ร ์ ไ ร ทิ น ใ น ซี ร ั ม
หลัง จากนั้ นจึง น าตัว อย่ า งเลือดที่เหลือ ทุ ก รายมาตรวจวินิ จฉั ย ธาลัสซีเมีย ณ ประเทศไทย จากตัว อย่า ง 275 ราย
พบความชุก ภาวะเลือ ดจาง และ ภาวะเลือ ดจางจากการขาดธาตุเหล็ ก เท่ ากับ ร ้อยละ 31.6 (95% CI = 26-37%)
และร ้อยละ 6 (95% CI = 4-11%) ตามล าดับ ผลการตรวจวินิ จ ฉั ย ธาลัส ซีเ มีย ผลการตรวจวินิ จ ฉั ย ธาลัส ซีเมีย
่ ความสาคัญทางคลินิก 3 ชนิ ด ไดแ้ ก่ 0-thalassemia ( 0-thal), -thalassemia
พบพาหะของธาลัสซีเมียทีมี
้ น
้ 57 ราย (ร ้อยละ 20.7) และพบว่ า ในกลุ่ ม ผู ท
( -thal) และ hemoglobin E (Hb E) รวมทังสิ
้ ี่มี ภ าวะเลือ ดจาง
มี ผู ้ เ ป็ น พ า ห ะ ธ า ลั ส ซี เ มี ย ร ้ อ ย ล ะ 42.5 มี ภ า ว ะ ข า ด ธ า ตุ เ ห ล็ ก ร ้ อ ย ล ะ 17.2
่ เคราะห ์ข ้อมูลโดยใช ้สมการถดถอยโลจิสติก พบว่า
เป็ นพาหะธาลัสซีเมียร่วมกับภาวะขาดธาตุเหล็ก ร ้อยละ 8.1 เมือวิ
่ มพันธ ์กับภาวะเลือดจางอย่างมีนัยสาคัญ คือ -thal [adjusted Odd ratio (AOR) = 66.4; 95%
ธาลัสซีเมียทีสั
0
CI = 8.3-533.7] แ ล ะ พ า ห ะ
-thal (AOR = 25.3; 95% CI = 8.9-72.5)
่
่ สด
เมือวิเคราะห ์ความสัมพันธ ์ระหว่างธาลัสซีเมียกับชาติพน
ั ธุ ์ พบว่า ชาติพน
ั ธุ ์ทีมี
ั ส่วนของ 0-thal และ -thal สูง
0
0
คือ Tay ( -thal ร ้อยละ 12.9 และ -thal ร ้อยละ 6.1), Muong ( -thal ร ้อยละ 10.9 และ -thal ร ้อยละ
2.2), และ Nung ( 0-thal ร ้อยละ 12.5 และ -thal ร ้อยละ 4.5) และชาติ พ ัน ธุ ท

์ ี่พบสัด ส่ ว น Hb E สู ง สุ ด คือ
Muong
(ร ้
อ
ย
ล
ะ
2
6
)
ผลการศึกษามีประโยชน์สาหร ับกาหนดมาตรการควบคุมภาวะเลือดจางและป้ องกันการแพร่กระจายของโรคธาลัสซีเมีย
ชนิ ดรุนแรงในภูมภ
ิ าค


ii
Hoa Thi Hong Hanh .Prevalence and risk factors for anemia among female students of ethnic
minorities in Thai Nguyen province, Vietnam.
Master of Science Thesis in Medical Sciences, Graduate School, KhonKaen University.
Thesis Advisor: Assoc. Prof. Dr. Kanokwan Sanchaisuriya
Co-Advisor: Asst. Prof. Dr Pattara Sanchaisuriya

ABSTRACT
Anemia is one of the health problems among ethnic minorities. In Vietnam, there are up to
54 ethnic minority groups residing in mountainous regions of the country. This study aimed to
determine the prevalence and risk factors for anemia among reproductive-age women of ethnic
minorities in northern Vietnam. Participants included 275 medical female students of various
minority groups studying at Thai Nguyen University. Information on socio-demographic and
health status was collected by means of interview. After getting written informed-consent, blood
samples were collected. Complete blood count was measured initially at Thai Nguyen General

Hospital. Blood samples of anemic individuals were determined further for serum ferritin. The
remaining blood samples were then carried to Thailand for investigation of thalassemia (thal). Of
the 275 women, the prevalence of anemia and iron deficiency anemia (IDA) was 31.6% (95% CI
= 26-37%), and 7.6 % (95% CI = 4-11%), respectively. The three forms of thalassemia, including
α0-thal, β-thal, and Hb E were identified in 57/275 women (20.7%). Amongst anemic women,
42.5% had thalassemia, and 17.2% had ID. Coincident of thal with ID was found in 7 women
(8.1%). Applying multiple logistic regression revealed that types of thalassemia that associated
significantly with anemia were -thal [adjusted OR (AOR) = 66.4 (95% CI 8.3-533.7)] and thal (AOR = 25.3; 95% CI = 8.9-72.5). Additional analysis of thalssemia in relation with ethnicities
revealed the high proportions of α0-thal and -thal among the Tay (12.9% 0-thal and 6% -thal),
Muong (10.9% 0-thal and 2.2% -thal), and Nung (12.5% 0-thal and 4.2% -thal). A highest
proportion of Hb E (26%) was detected in the Muong group. The results are useful for
implementing appropriate measures to control anemia and prevent the spread of severe thalassemia
syndromes in this region.


iii

Goodness portion of the present thesis is dedicated to my parents, my thesis
advisory committee and the entire teaching staff


iv

ACKNOWLEDGEMENTS
I would like to express my deepest and sincere gratitude to my research advisor, Associate
Professor Kanokwan Sanchaisuriya, and my co-advisor, Assistant Professor Pattara Sanchaisuriya
for their kindness to provide me an opportunity to be their advisee and for their valuable
motivation, suggestions, and guidance throughout my study.
I would like to express my greatest appreciation and sincere to Faculty of Associated
Medical Sciences, Khon Kaen university and Khon Kaen University for giving me a scholarship

for studying here.
I would like to take this opportunity to thank all the professors in the Faculty of Associated
Medical Sciences for providing me valuable knowledge and experience during my study.
I am also very grateful to Prof. Dr. Sastri Saowakhontha, Prof. Dr. Supan Fucharoen,
Assoc. Prof. Goonnapa Fucharoen, Prof. Dr. Arunee Jetsrisuparp for being as examination
committee and for their valuable suggestions as well as encouragement.
I would like to thank Dr. Attawut Chaibunruang, Assist. Prof. Dr. Supawadee Yamsri, Dr.
Hataichanok Sriwarakun, Miss Jutatip Jamnok, Mr Phongsathorn Wichian, Miss Benchawan
Kingchaiyaphum, graduate students of Thalassemia Group and other graduate students. Faculty of
Associated Medical Sciences, Khon Kaen University as well as my family for the suggestion,
support, consolation, helpful, cheerfulness and friendliness.
Finally, I deeply appreciate the financial support from the Centre for Research and
Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical
Sciences, Khon Kaen University.
Hoa Thi Hong Hanh


v

TABLE OF CONTENTS
ABSTRACT ................................................................................................................................................. ii
LIST OF TABLES .................................................................................................................................... vii
LIST OF ABBREVIATIONS ................................................................................................................. viii
CHAPTER I INTRODUCTION ............................................................................................................... 1
1. Background and rationale ..................................................................................................................... 1
2. Research questions ............................................................................................................................... 2
3. Objectives ............................................................................................................................................. 2
4. Anticipated outcomes............................................................................................................................ 3
CHAPER II LITERATURE REVIEW..................................................................................................... 4
Part I: General consideration of anemia, ID and IDA ............................................................................... 4

1. Anemia .............................................................................................................................................. 4
2. Iron deficiency (ID) and iron deficiency anemia (IDA) ................................................................... 5
Part II: Related research ............................................................................................................................ 6
1. Prevalence and risk factors for anemia in Vietnam .......................................................................... 6
2. Prevalence of thalassemia and hemoglobinopathies in Vietnam..................................................... 9
Conceptual framework ............................................................................................................................ 11
CHAPTER III RESEARCH METHODOLOGY .................................................................................. 12
1. Study design ........................................................................................................................................ 12
2. Study population ................................................................................................................................. 12
3. Sample size ......................................................................................................................................... 12
4. Data collection & tools ....................................................................................................................... 13
5. Statistical analysis ............................................................................................................................... 14
6. Ethical consideration ........................................................................................................................... 14
7. Scope and limitation of the study........................................................................................................ 14
CHAPTER IV RESULTS ........................................................................................................................ 16
1. General characteristics of the study population .................................................................................. 16
2. Prevalence of anemia, IDA, and thalassemia among 275 women of ethnic minorities ...................... 16
3. Hematologic features among anemic and non-anemic women. .......................................................... 17
4. Factors associated with anemia among 275 women of ethnic minorities ........................................... 17
5. Distribution of thalassemia among different ethnic groups ................................................................ 17


vi
CHAPER V DISCUSSION ...................................................................................................................... 26
CHAPER VI CONCLUSION .................................................................................................................. 29
REFERENCES .......................................................................................................................................... 30
APPENDIX A INFORMATION SHEET ............................................................................................... 34
APPENDIX B QUESTIONNAIRE FORM ............................................................................................ 39
APPENDIX C ETHICAL APPROVAL FORM .................................................................................... 44
APPENDIX D RESEACH PRESENTATION ....................................................................................... 45

vii

LIST OF TABLES

Page
Table 1

Classification of anemia by age and gender

4

Table 2

Causes of iron deficiency

6

Table 3

Prevalence of anemia in Vietnam

8

Table 4

Prevalence of the three clinically significant thalassemia in Vietnam

10

Table 5

Socio-demographic characteristics of the 275 participants

18

Table 6

Basic information on health status of the 275 participants

19

Table 7

Prevalence of anemia, IDA, and thalassemia among 275 women of

20

ethnic minorities
Table 8

Prevalence of the three clinically significant thalassemia among 275

21

reproductive-age women of ethnic minorities
Table 9

Proportions of factors explaining anemia among 87 women

22

Table 10

Hematological characteristics of anemic and non-anemic women;

23

categorized by thalassemia and iron status
Table 11

Effect of thalassemia types on anemia

24

Table 12

Distribution of the 3 clinically significant thalassemia among 275

25

reproductive-age women with different ethnicities


viii

LIST OF ABBREVIATIONS

CHC

CI
EDTA
DCIP
DHC
GDP
Hb
Hct
ID
IDA
MCV
MCH
MCHC
RBC
RDW

Commune health center
Confident interval
Ethylenediaminetetraacetic acid
Dichlorophenol-indophenol
District Health Center
Gross Domestic Products
Hemoglobin
Hematocrit
Iron deficiency
Iron deficiency anemia
Mean corpuscular volume
Mean corpuscular hemoglobin
Mean corpuscular hemoglobin concentration
Red blood cell
Red blood cell distribution width

1
CHAPTER I
INTRODUCTION

1. Background and rationale
Anemia is a condition in which hemoglobin (Hb) and/or red blood cell (RBC) production
is reduced. Anemia is defined as Hb concentration less than cutoff value adjusted for age and sex;
i.e. Hb < 11 g/dl for pregnant women and Hb < 12 g/dl for non-pregnant women [1]. Individuals
with anemia may have unpleasant outcomes that lead to reduced work performance such as fatigue,
dizziness, headache and shortness of breath. When anemia becomes severe (Hb < 7.0 g/dL), heart
failure may occur [2]. Therefore, it is necessary to implement prevention program for anemia
among the high risk population.
Population in developing countries are considered at high risk due partly to the low socioeconomic status. According to the World Health Organization (WHO), approximately 50% of
Southeast Asian populations are anemic [1]. It is assumed that iron deficiency (ID) is the main
cause. Poor consumption of dietary iron is thought to be related to anemia, the so-called iron
deficiency anemia (IDA). While preschool-age children and pregnant women are at high risk
because of the increased requirement of iron, non-pregnant women of reproductive age are also atrisk due to regular blood loss [2]. Other causes include parasitic infections and micronutrient
deficiency as well as inherited hemoglobin disorders, thalassemia and hemoglobinopathies.
Several studies conducting in this region have shown that the inherited disorders rather than ID
are associated with anemia [3-6].
Vietnam is one of developing countries in Southeast Asia where there are up to 54 different
ethnic groups. Amongst these ethnicities, the Kinh (Viet) is the majority group, accounting for
nearly 86% of Vietnamese population [7]. Other minority groups reside in mountainous areas
where health care accessibility is limited. Previous studies conducting in the country have
demonstrated the high prevalence of thalassemia and hemoglobinopathies in several groups of
ethnic minorities [8-11]. It is therefore of interest to investigate the prevalence of anemia and its
risk factors among the minorities.

2
Thai Nguyen University of Medicine and Pharmacy (TUMP) is in the Northeast of Vietnam
and plays a key role in producing medical doctors for the mountainous provinces of Vietnam.
TUMP has approximate five thousand students, of which more than a third are ethnic minority
students. They come from different areas of the northeastern region where the rate of malnutrition
is high [12-14]. Being reproductive-age females of ethnic minorities, the risk of anemia is thought
to be high. This study aims to determine the prevalence and risk factors for anemia among females
of ethnic minorities studying at the TUMP. Information gained will be useful for implementing
appropriate control program for anemia among the reproductive-age female of ethnic minorities.

2. Research questions

2.1 What is the prevalence of anemia among females of ethnic minorities studying at
TUMP?

2.2 What are the factors associated with anemia among females of ethnic minorities
studying at TUMP?

3. Objectives

3.1

General objective
To determine the prevalence of anemia among female students of ethnic minorities

studying at TUMP

3.2

Specific objectives
3.2.1 To determine the prevalence of anemia, IDA, and the 3 clinically significant
thalassemia, i.e. α0-thal, β-thal, and Hb E among female students of ethnic
minorities studying at TUMP
3.2.2 To compare the proportions of ID and thalassemia among anemic women
studying at TUMP
3.2.3 To describe hematologic features among anemic and non-anemic women of
ethnic minorities studying at TUMP
3.2.4 To identify risk factors for anemia among female students of ethnic minorities
studying at TUMP
3.2.5 To explore the distribution of different types of thalassemia among different
ethnic groups


3
4. Anticipated outcomes
Basic information on anemia prevalence and risk factors would be useful for implementing
an appropriate prevention program for anemia among reproductive-age females of ethnic
minorities in Vietnam. The additional study on the distribution of thalassemia types is expected to
inspire health staff and policy makers to initiate prevention program for thalassemia among the
ethnic minority groups.


4
CHAPER II
LITERATURE REVIEW

Part I: General consideration of anemia, ID and IDA
1. Anemia
Anemia is a condition that occurs when there is a limit production of red blood

cells or hemoglobin. Anemia is considered as one of the major public health problems affecting
more than half of the world population. It has significant adverse effect on health as well as on
social and economic development. The severity of anemia depends on many factors including age,
sex, physiological and pathological statuses. In public health term, anemia is defined when Hb
level is lower the thresholds given by the WHO (Table 1) [1].
Table 1: Classification of anemia by age and gender [1]
Age and gender group

Hb threshold (g/dL)

Children (6 months to under 5 years)

11

Children (5 years to under 12 years)

11.5

Children (12 years to under 15 years)

12

Non-pregnant women (15 years and over)

12

Pregnant women

11

Men (15 years and over)

13

There are many ways to classify anemia. Using MCV as classification criterion, there are
three groups; microcytic anemia (MCV < 80 fl), normocytic anemia (MCV 80-100 fl), and
macrocytic anemia (MCV > 100 fl) [2]. Based on the mechanism that causes anemia, three
categories are defined, i.e. deficient erythropoiesis (impaired RBC production), excessive RBC
destruction, and blood loss. Blood loss can be either acute or chronic. Acute blood loss usually
results from bleeding due to accident or injuries. Many chronic diseases such as malignancies,
gastrointestinal tract lesions, gynecologic disturbances, etc. cause chronic blood loss. Deficient
erythropoiesis and excessive RBC destruction (hemolysis) result from many causes. While ID
results in deficient erythropoiesis, inherited Hb disorders (thalassemia & hemoglobinopathies) can


5
result in either deficient erythropoiesis or excessive hemolysis depending on the number and types
of abnormal genes inherited [2,15].
Anemia may occur at any age. But it can be found commonly in preschool – age children,
pregnant women and non – pregnant women of reproductive age [1]. Individuals with anemia may
have several unpleasant clinical symptoms depending on its cause and severity. Signs and
symptoms of anemia may include headache, dizziness, weakness and fatigue, shortness of breath,
chest pain, and irregular heartbeat. Anemia may also result in slowed growth development, poor
cognitive performance and behavioral disturbance in young children [16-18]. For pregnant women,
many poor maternal outcomes such as risk of perinatal mortality and morbidity have been reported
[19-21]. For non-pregnant women of reproductive age and other groups of population, anemia
usually results in reduced work performance. When anemia becomes severe, other serious health
consequences could occur and may lead to heart attack or failure [2].

2. Iron deficiency (ID) and iron deficiency anemia (IDA)

ID is the most common nutritional deficiency worldwide. It results from a long-term of
negative iron balance. The early stage of ID starts with a depletion of iron stores, and it does not
cause physiological impairment. At this stage, the iron storage is reduced but serum iron remains
normal. Without iron replacement, deficient erythropoiesis occurs, leading to anemia, so-called
iron deficiency anemia (IDA). As a result, Hb level as well as mean cell volume (MCV) and mean
cell hemoglobin (MCH) reduce significantly. Therefore, a reduction in Hb, MCV and MCH values
is used widely as indicator of IDA [2]. A definite diagnosis of ID requires measurement of iron
stores, serum ferritin (SF). In an absence of infection or inflammation, SF is considered as the most
reliable biomarker for detecting iron deficiency. According to the WHO, anemic individuals with
SF < 15 ng/ml are diagnosed as having IDA [22]. However, it is suggested that this marker should
be used in an area where the incidence of malaria and parasitic infestation is low.
Causes of IDA can be categorized into 3 main groups, i.e. increased iron requirements,
insufficient intake, and impaired iron absorption (Table 2). While the high risk groups like young
children and pregnant women require more iron for growth development (for themselves and the
developing fetus), non-pregnant women of reproductive age requires more iron for compensation
of blood loss via menstruation.


6
Table 2: Causes of iron deficiency [23]
Increased iron requirements
- Growth
- Menstruation
- Pregnancy
- Lactation
- Blood los from other causes
Insufficient intake
- Vegan diet
- Limited diet
- Malnutrition

Impaired absorption
- Intestinal malabsorption
- Gastric surgery
- Hypochlorhydria

Part II: Related research
1. Prevalence and risk factors for anemia in Vietnam
In Vietnam, the prevalence of anemia has improved over time. The prevalence of anemia
varies greatly depending on study population and areas. Data on anemia prevalence collected before
2009 have shown a high prevalence of anemia in the country, ranging from 20-62% [24]. The
prevalence was particularly high among population living in rural areas.
A large survey representing the burden of anemia in the country had been conducted in
1995 by Nguyen et al [25]. The authors conducted a cross-sectional survey for anemia in rural
areas of 53 provinces. Children, pregnant and non-pregnant women as well as men were recruited
from 9,500 households. A high prevalence of anemia of 60% was found in young children aged
under 2 years. Anemia prevalence among pregnant and non-pregnant women of reproductive was
53% and 40%, respectively. They also found that 16% of men were anemic. The strongest factor
associated with anemia was found to be hookworm infection. Risk factors associated with anemia
among children and women included living in different ecological zones, eating < 1 serving of


7
meat/ week, and farming. Additional risk factors for women were having > 3 children and having
a child < 24 months old.
Similarly high prevalence of anemia among the three high risk groups, i.e. children,
pregnant and non-pregnant women of reproductive-age, was also reported by several groups of
investigators. Nhien et al. [26, 27] reported the anemia prevalence of 45% among primary school
children, and 56% among young children aged 12 to 72 months, whereas Le et al. [28] reported a
relatively lower anemia prevalence of 25% among school children residing in Tam Nong district.
For adolescent school girls, the occurrence of anemia appeared to be lower than young children

with a prevalence of 20% [29]. In pregnant women, anemia prevalence of 43-53% has been
reported [30,31]. Studies conducting in non-pregnant women of reproductive-age demonstrated a
high prevalence of 54% in 2007 [31], and reduced to 38% in 2008 and 2009 [32, 33]. In addition
to ID and hookworm infection, micronutrient deficiencies including selenium, zinc, copper, and
vitamin A were shown to be associated with anemia [12-14, 28, 32, 34]. The association between
ethnicity and anemia has also been demonstrated in a cohort study conducting in a minority
community, in which ID and malaria were found to be potential factors associated with anemia
within the study population [34].
After 2010, the reported prevalence of anemia in Vietnam reduced dramatically. Laillou et
al [35] reported an unexpectedly low prevalence of 9-12% for anemia, and 13-14% for ID in two
study groups, reproductive-age females and children aged 6-75 months. Later, a study conducted
in pregnant women residing in Thua Thien Hue reported a prevalence of 19% for anemia, 20% for
ID, and 6% for IDA [36]. Similarly, a prevalence of anemia of 22% and 20% was reported by Tran
et al in 2014 [37], and by Nguyen et al in 2016 [38]. More recently, a study conducted in children
aged 6-11 years also showed unexpectedly low prevalence of 11% for anemia, 6% for ID and 0.4%
for IDA [39]. These results indicate an improvement of anemia burden within the country.
However, it is noticeable that information on the health burden among the ethnic minority groups
is limited.
A summary of anemia prevalence in Vietnam is shown in Table 3.


8
Table 3. Prevalence of anemia in Vietnam
Prevalence

Study population

Study area

Sample size

Children aged < 2 years

53 provinces

9550

60

household

53

Pregnant women

(%)

Non – pregnant women*
Primary school children (aged

References
[25]

40
Bac Ninh province

292

11.3

[26]

Children aged 1 – 6 years

Thai Nguyen

243

55.6

[27]

Adolescent girls (age: 11 – 17

Ha Nam province

245

20.4

[29]

Dak Lak province

281

53

[31]

348

62

[31]

272

54

[31]

Yen Bai province

354

37.5

[32]

Yen Bai province

408

37.5

[33]

Thua Thien Hue

425

20

[36]

6-9 years)

years)
Pregnant women (age: 15-49
years)
Post partum women (age: 15-49
years)
Non-pregnant women (age: 1549 years)
Reproductive age women
(age: 16-49 years)
Reproductive age women (age:
15 – 45 years)
Pregnant women

province
*Age of women was not specified.


9
2. Prevalence of thalassemia and hemoglobinopathies in Vietnam
A few community-based surveys for thalassemia had been conducted in Vietnam. A large
survey was conducted in 2010 by O’Riordan et al [8]. The investigators reported the results of
thalassemia screening in > 9000 individuals with different ethnicity in South Vietnam. They found
that the gene frequencies of thalassemia among ethnic minority groups (including Tay, Dao, Nung,

S’Tieng, M’Nong, Rac Lay and E De) varied considerably, ranging from 0-9.5% for β-thal, and
0-58% for Hb E. The proportions of α0-thal investigated among the 3 minority groups, i.e. Tay,
Nung, and S’Tieng, ranged from 5.5- 6.9%. The prevalence among the Kinh, the majority group
of Vietnamese, was 3.4% for α0-thal, 1.6% for β-thal and 3.4% for Hb E. Later, similar prevalence
of α0-thal (3.4%) and β-thal (1.5%) with slightly lower prevalence of β-thal (2.1%) was reported
among the Kinh pregnant women who attended antenatal care service at 40 health commune
centers in Thua Thien Hue [9].
Previous studies surveying thalassemia among 2 ethnic minority groups, the Co-Tu and
Ta-Oi, in Central Vietnam, reported the remarkably high prevalence of Hb CS of around 25%,
which was the highest prevalence reported so far [10, 11]. A carrier frequency of Hb E of
approximately 15% was observed in both groups. Interestingly, none of α0-thal was identified.
A summary of the three clinically significant thalassemia in Vietnam is shown in Table 4.


10
Table 4. Prevalence of the three clinically significant thalassemia in Vietnam
Study

Study area

population

Kinh

Prevalence
α0-thal

References

β-thal Hb E

southern and central southern Vietnam

3.4

1.6

3.4

[8]

Thua Thien Hue

3.4

1.5

2.1

[9]

Co-Tu*

Thua Thien Hue

0

0.34

11.4

[9]

Tay

southern and central southern Vietnam

5.5

7.6

2.8

[8]

Nung

southern and central southern Vietnam

6.8

8.1

2.0

[8]

Dao

southern and central southern Vietnam

NA

9.5

0

[8]

Ta-Oi*

Thua Thien Hue

0

0

14.6

[11]

*The most prevalent thalassemia among the Co-Tu and Ta-Oi was Hb CS with a carrier
frequency of around 25%.


11
Conceptual framework
Based on the literature reviews, the conceptual framework of this study is shown below.
Independent variable

Dependent variable

Socio – Demographic information
- Age
- Ethnicity
- Residence
- Family income
- Marital status

Food consumption practices

Anemia status

- Meat consumption

- Yes

- Tea/coffee consumption

-No

Health status
- BMI
- History of illness
- History of Blood loss

Thalassemia and
hemoglobinopathies

12
CHAPTER III
RESEARCH METHODOLOGY

1. Study design
The cross-sectional survey was conducted at Thai Nguyen University of Medicine and
Pharmacy (TUMP), Thai Nguyen province, Vietnam.
The research was conducted through 2 subsequent steps
Step 1: Face to face interview
Face-to-face interview using questionnaires was applied to collect basic information
including age, weight, height, ethnicity, educational background, family income, iron
supplementation, and medical history (i.e. history of blood loss, chronic disease and/or other
infection or inflammation, as well as family history of thalassemia).
Step2: Blood collection
Venipuncture was performed to collect blood samples for investigation of anemia, ID and
thalassemia.

2. Study population
The study population included apparently healthy female students of any ethnic minority
group studying at Thai Nguyen University of Medicine and Pharmacy. Only females aged 18-35
years were recruited. Participation was voluntary. Pregnant females were excluded.

3. Sample size
Sample size was calculated using the formula for estimating population proportion as
follows;

𝑛=

2
𝑁 𝑃(1 − 𝑃)𝑍1−

𝛼
2

𝑒 2 (𝑁 − 1) + 𝑃 (1 − 𝑃)𝑍 2

𝛼
1− 2


13

Where,

95% confident interval (Zα/2)

= 1.96

Prevalence of anemia in student (P) = 0. 37 [32]
Precision of estimation (e)

= 0.05

A total number of female ethnic minority students (N) studying at TUMP = 829

Therefore,

n=

1,000 0.37 (1−0.37) 1.962
0.052 (1,000−1)+0.37 (1−0.37)1.962

n = 250

A sample size of 250 normal individuals was required for estimation prevalence of anemia
in Thai Nguyen University of Medicine and Pharmacy. To compensate for sample loss, 10% of
total selected students was added. Thus, a total of 275 female students were recruited.

4. Data collection & tools
Basic information was collected by interviewing using questionnaires. This process was
done by well-trained research assistants. Details of questionnaires are show in Appendix I.
After interviewing, blood sample was collected by staff of Thai Nguyen Institute of
Hematology and Blood Transfusion. Three milliliters (ml) of venous blood sample anticoagulated
with EDTA was taken from all participants. After collection, all blood samples were kept at 2-6oC
and sent to Thai Nguyen Institute of Hematology and Blood Transfusion to determine anemia and
other hematologic parameters using an automated hematology analyzer (Unicel DxH 800,
Beckman Coulter, USA). Portions of blood samples were sent on ice to the Centre for Research
and Development of Medical Diagnostic Laboratories (CMDL), Khon Kaen University, Khon
Kaen, Thailand, for diagnosis of thalassemia and hemoglobinopathies.
Anemia was defined according to the WHO criteria (Hb < 12.0 g/dl) [1]. Blood samples of
anemic cases were investigated further for serum ferritin using the latex agglutination reagent kit


14
(Beckman Coulter Inc., CA, USA). Anemic individual with SF < 15 ng/ml was diagnosed as IDA
[22].

Approach to diagnosis of thalassemia
At CMDL, all blood samples were screened for Hb E using the KKU-DCIP-Clear reagent
kit (PCL Holdings, Bangkok, Thailand). Cellulose acetate electrophoresis (Helela Laboratories,
Beaumont, Texas, USA) was initially performed to identify Hb types. Then, blood samples with

normal Hb-type (A2A) together with either MCV < 80 fl or MCH < 27 pg were selected for further
determination of Hb A2 level. Individual with Hb A2 > 3.5% was concluded as β-thalassemia trait.
Identification of α0-thal was performed in all samples using a multiplex gap-PCR for SEA and
THAI deletions [40].

5. Statistical analysis
Data were analyzed using SPSS for Windows program (version 20.0, SPSS, Chicago, IL,
USA). Prevalence of anemia, IDA, and the clinically significant thalassemia was summarized as
percentage with 95% confidence interval (95% CI). Normally distributed continuous variables
including hematological parameters were presented as mean with standard deviation. The
association between anemia and selected factors (including socio-economic information, food
consumption behavior, health status and history of blood loss, as well as thalassemia types) was
tested with Chi-square test. To demonstrate the effect of different types of thalassemia on anemia,
all ID and homozygous Hb E cases were excluded. Multiple logistic regression was then applied
to calculate the odd ratio (OR) and 95% CI. P-value < 0.05 was considered statistically significant
for all analyses.

6. Ethical consideration
This study was approved by the Ethics Committee of Khon Kaen University and TUMP.
Written informed consent was obtained prior to blood collection.

7. Scope and limitation of the study
This study was a cross-sectional study aiming to determine the prevalence of anemia and
its risk factors among reproductive-age females of ethnic minorities. The investigated risk factors