Table 12 illustrates the proportions of the three clinically significant thalassemia among different ethnic minority groups. All these three forms of thalassemia were observed in almost all minority groups. A high proportion of α0-thal was detected in Tay (12.9%), Muong (10.9%), and Nung (12.5%). Other minority groups in which α0-thal was identified were Thai, Cao Lan, Tho and San Dui. For β-thal, a high proportion of 6% was observed in the Tay group. Around 4% of the Nung women were found to be β-thal carriers. Comparing with Tay and Nung, Muong women had a relatively lower proportion of β-thal (2.2%) with a significantly higher proportion of Hb E (26.1%). Women carrying β-thal and Hb E genes were also identified among other minority groups, including Thai, Hoa, Tho and San Dui.
Table 5: Socio-demographic characteristics of the 275 participants
Characteristic N Percent
Age Ethnicity - Tay - Nung - Muong - Thai - Dao - San Diu - Other groupsa
Mean (SD) 116
49 46 15 13 13 23
22.8 (1.8) 42.2 17.8 16.7 5.5 4.7 4.7 8.4 Resident
- Urban - Rural
28 247
10.2 89.8 Education level
1st – 3nd 4 – 6th
106 169
38.5 61.5 Marital Status
- Yes - No
15 260
5.5 94.5 Number of Children
- 0 - 1-2
268 7
97.5 2.5 Family incomeb
- Low
- Lower Middle - Middle
- High
5 45 58 167
1.8 16.4 21.1 60.7
a. Other groups included 7 Muong, 5 San Chi, 4 Cao Lan, 2 Pa Di, 2 Tho, 1 Giay, 1 Hoa, and 1 Ngan
b. Classified by the local government using monthly income as an indicator in rural area as follows: low <700.000 VND, lower middle: 700.000 – ≤1.000.000 VND, middle: 1.000.000 –
≤1.500.00 VND, high: >1.500.000 VND.
Table 6: Basic information on health status of the 275 participants
Characteristic N Percent
BMI - <18.5 - 18.5 – 24.9 - 25.30
82 184 9
29.8 66.9 3.3 Chronic illness
- Yes - No
33 242
12.0 88.0 Peptic ulcer
- Yes - No
43 232
15.6 84.4 Duration of menstruation
- < 3 days - 3 – 5 days - > 5 days
4 219 52
1.5 79.6 18.8 Number of menstrual pads used / day
- < 3 pads - 3 – 5 pads - 6 – 10 pads - >10 pads
9 239 25 2
3.3 86.9 9.1 0.7 Tea/coffee consumption
- Yes - No
90 185
32.7 67.3
Table 7 Prevalence of anemia, IDA, and thalassemia among 275 women of ethnic minorities
Disease n Prevalence (%) 95% CI
Anemia 87 31.6 26 – 37
IDA 21 7.6 4 – 11
Thalassemiaa or
structural Hb variantb 60 21.8 17.1–28
a: Thalassemia included α0-thal, β-thal and Hb E b: There were 2 cases with structural Hb variants.
Table 8 Prevalence of the three clinically significant thalassemia among 275 reproductive- age women of ethnic minorities
Type of thalassemia n Percent 95% CI
α0-thala 31 11.3 7.8-15.6
β-thalb 13 4.7 2.5-7.9
Hb Ec 19 6.9 4.2-10.6
a: Including 2 cases with β-thal and 5 cases with Hb E b: Including 2 cases with α0-thal
c: Including 5 cases with Hb E
Table 9 Proportions of factors explaining anemia among 87 women
Factors n Percent
Thalassemia (thal)* 37 42.5
Iron deficiency (ID) 15 17.2
Coincidence of thal and ID 7 8.1
Unknown 28 32.2
*Comprising α0-thal, β-thal, Hb E, and their interaction
Table 10 Hematological characteristics of anemic and non-anemic women; categorized by thalassemia and iron status; data presented as mean ± standard deviation, or as raw data where appropriate
Subject group
Thal category
Iron status n RBC (x1012/l) Hb (g/dl) MCV (fl) MCH (pg) RDW (%)
Anemia Het. 0-thal Non-ID 16 5.4±0.3 11.1±0.4 65.2±3.1 20.4±1.0 15.5±0.8
ID 4 5.2±0.7 10.5±1.0 64.2±7.9 20.2±2.9 18.2±2.9
Het. -thal Non-ID 9 5.8±0.3 10.8±0.4 59.7±2.2 18.8±0.7 15.8±0.7
ID 1 585 10.9 58.8 18.6 16.2
Double het. -thal /0-thal Non-ID 2 4.81, 5.38 10.7, 11.5 71.6, 68.8 22.3, 21.4 15.2, 15.1
Het. Hb E Non-ID 4 4.6±0.2 11.5±0.4 77.0±2.9 25.4±0.9 13.8±0.5
ID 2 6.37, 4.59 9.7, 10.8 51.5, 73.6 15.2, 23.5 21.8, 15.7
Het. Hb E with het. 0-thal Non-ID 4 5.6±0.3 11.3±0.4 63.9±5.2 20.2±1.5 15.7±0.6
Homozygous Hb E Non-ID 1 5.94 9.7 51.4 16.4 17.1
Hb H disease Non-ID 1 5.18 9.0 58.3 17.4 20.8
Non-thal or non-clinically significant thal
Non-ID 29 4.2±0.5 11.6±0.3 83.9±7.3 27.7±2.8 13.6±0.9
ID 14 4.4±0.3 10.7±0.7 75.9±8.1 24.4±2.9 16.0±1.7
Non-anemia Het. 0-thal ND 4 6.0±0.2 12.4±0.4 65.2±3.4 20.6±1.1 15.7±0.6
Het. -thal ND 1 5.55 13.1 74.8 23.7 14.7
Het. Hb E ND 7 5.1±0.2 12.6±0.4 75.0±1.6 24.7±0.6 14.1±0.6
Het. Hb E with het. 0-thal ND 1 5.76 12.5 66.0 21.6 15.0
Carrier of abnormal Hb ND 2 4.56, 4.68 13.1, 12.9 87.0, 83.2 28.8, 27.6 14.2, 13.3
Non-thal or non-clinically
significant thal ND 173 4.5±0.3 12.9±0.6 86.1±4.4 28.6±1.7 13.4±0.8
ND = not determined
Table 11 Effect of thalassemia types on anemia
Type of thalassemia (n) No. of anemia (%) OR (95% CI) p-value
Non-thal (n = 204) 29 (14.2) 1 -
α0-thal (n =26)a 21 (80.8) 25.3 (8.9-72.5) < 0.001 β-thal (n=12)b 11 (91.7) 66.4 (8.3-533.7) < 0.001
Hb E (n=11) 4 (36.4) 3.4 (0.9-12.5) 0.060
a:Including the concomitance of α0-thal with Hb E (n=5) and Hb H (n=1) b: Including the concomitance of β-thal with α0-thal (n = 2)
Table 12 Distribution of the 3 clinically significant thalassemia among 275 reproductive- age women with different ethnicities
Ethnicity n Thalassemia types; n (%)
α0-thal β-thal Hb E
Tay 116 15 (12.9)b 7 (6.0) 3 (2.6)
Muong 46 5 (10.9) 1 (2.2) 12 (26.1)
Nung 49 5 (12.5) 2(4.2) 0
Other groupsa 64 6 (9.4)c 3 (4.9)d 4 (6.1)e
a: Including Dao, San Diu, Pa Di, Thai, San Chi, Mong, Ngan, Cao Lan, Tho, Hoa, Giay b: THAI deletion was detected in 1 case
c: Including 2 Thai, 2 Cao Lan, and 1 Tho, and 1 San Dui d: Including 2 Thai and 1 Hoa
e: Including 2 Thai 1 Tho, and 1 San Dui
CHAPER V DISCUSSION
As part of the government efforts, one mission of the TUMP is to produce medical student to serve the minority community in northern region. This study was conducted with a goal of initiating concerns about burden of anemia among the minorities. The results showed that prevalence of anemia remains high among the study participants. However, the low prevalence of IDA and a relatively lower proportion of ID among anemic participants (as compared to thalassemia) suggest that ID is not the main factor responsible for anemia in this population. This information is useful for health personnel to provide appropriate care and management of anemia among the minorities.
According to the global anemia in 2011 reported by the WHO [41], the estimate prevalence of anemia among Vietnamese women of reproductive-age was 14% (95% CI = 9- 24%), indicating a significant improvement in anemia burden in the country, as compared to the prevalence of 24% (95% CI = 23-26%) estimated during 1993-2005 [1]. Baseline data from 4986 women of reproductive-age who participated a randomized controlled trial (PRECONCEPT) reported in 2015 by Nguyen et al [42] revealed an anemia prevalence of 19.7%. In contrary, this study reported a higher prevalence of anemia of 31% (Table 7).
Considering that the participating women were of ethnic minorities, the high prevalence of anemia may relate to not only the ID but also genetic factors.
Both ID and thalassemia traits are considered as the most potential factors associated with anemia as they link directly to hemoglobin synthesis [2,15]. In developing countries, ID is thought to be the most common cause because of the low socio-economic status. Being minorities, the risk to IDA is believed to be high due to their poverty and inaccessibility to health care system. Although, all participants were of various ethnic minority groups, they were medical students who were considered well educated. As expected, the prevalence of IDA of 7.6% is within the same range as reported in Vietnam and neighboring countries during the past decade [3-6,43] indicating that ID may not be main factor responsible for anemia in this region.
A high prevalence of thalassemia in various groups of ethnic minorities in Vietnam has been documented [8-11] This study found the same results in that the prevalence of thalassemia among the study participants was high (Table 7), although only three forms, i.e. α0-
thal, β-thal and Hb E, were investigated. A high proportion of thalassemia among anemic women supports that thalassemia are the major factors responsible for anemia. It is also shown that these 3 forms of thalassemia were associated significantly with anemia, and β-thal showed strongest effect on anemia among participants (OR = 66.4; 95% CI = 8.3-533.7) (Table 11).
Contradictory to this study, a previous study conducted in northeast Thailand documented that homozygous state of Hb E had strongest effect on anemia [3]. The fact that types of thalassemia found in each population can differ from each other could explain this dissimilarity. It is of note that around one-third of anemic women remain unexplained (Table 9). It is likely that other forms of thalassemia that were not investigated in this study, i.e. α+- thal and Hb CS, may contribute to anemia among these women. These thalassemia had been reported among the Tay and Nung groups [8]. Other possible causes include the deficiency in micronutrients such as vitamin A, zinc and selenium [26-29]. Vitamin B12, folic acid is unlikely to be the cause because Vietnamese food usually contains fish source. Infection with malaria and hookworm seems not to cause anemia as participants were medical students who received regular health-checks.
Considering that hemoglobin (Hb) level has long been used widely as proxy indicator for surveying IDA in a population [22], it appears that Hb is not reliable for use in a setting where thalassemia are highly prevalent. As shown in Table 10, most of thalassemia carriers were anemic although some of thalassemia carriers had no anemia. Co-incident of thalassemia with ID resulted in an increased severity of anemia, as indicated by a significant reduction in Hb levels. These hematologic changes were comparable to that has been reported previously in this region [3], confirming the similar effect of thalassemia and ID on hematologic features. It is crucial for ID individuals to receive iron supplementation to prevent the adverse effect of severe anemia. Further studies are therefore needed to identify effective biomarkers for predicting ID in a setting where thalassemia are highly prevalent.
Due to the high prevalence of thalassemia among the study participants, it is recommended that prevention program should be established to avoid the occurrence of newborns with severe thalassemia syndromes. In this region, the diseases considered to be a serious public health problem are homozygous α0-thal (Hb Bart’s hydrops fetalis), homozygous β-thal and compound heterozygous state of Hb E with β-thal [44]. Amongst the minorities participated in this study, the Tay was the largest group. A previous study conducting in various groups of ethnic minorities living southern Vietnam reported 5.5% α0-thal, 7.6% β-thal, and 2.8% Hb E among the Tay [8]. This study reported a relatively higher proportion of α0-thal
of 12.9%, reflecting a higher chance of having newborns with Hb Bart’s hydrops fetalis within this minority group residing in northern region. The proportion of α0-thal was also high in the Nung and Muong minority groups (Table 12). In addition to α0-thal, β-thal and Hb E were observed almost all groups, emphasizing a serious health burden due to severe thalassemia syndromes among the minorities. Similar to that has been observed in northeast Thailand [3,45,46], a high proportion of Hb E with relatively lower proportion of β-thal was observed in the Moung group, probably suggesting the population migration across the region. Although the sample size of each ethnic group was small, the existence of the three clinically significant thalassemia among the minorities suggests a need for systematic surveys in all minority groups in northern Vietnam.
CHAPER VI CONCLUSION
In conclusion, this study provides evidence supporting the high prevalence of anemia and high frequencies of the 3 clinically significant thalassemia among the minorities in northern Vietnam .The fact that all these minorities live side by side in mountainous areas, interracial marriage can happen frequently. Appropriate measures to prevent the occurrence of severe thalassemia syndromes resulting from homozygous α0-thal hydrops fetalis, homozygous β-thal and compound heterozygous Hb E- β - thal are needed. These findings will be useful not only for the development of prevention program for anemia and thalassemia but also for further studies on population genetics in Southeast Asia.
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APPENDIX – A
Information sheet and consent form
INFORMATION SHEET
Project title: Prevalence and risk factors for anemia among female students of ethnic minorities in Thai Nguyen Province, Vietnam.
Principal researcher: Miss. Hoa Thi Hong Hanh Co-researcher: MD, MDH, PHd. Hac Van Vinh Introduction:
Anemia is a condition in which hemoglobin and/or red blood cell production is reduced. The condition may result in many unpleasant outcomes such as weakness & fatigue, dizziness, shortness of breath, and if left untreated, heart failure may occur. It is considered as one of the major public health problems requiring a proper prevention program.
According to the World Health Organization, the prevalence of anemia is particularly high in developing countries. The most common cause is thought to be iron deficiency (ID).
Besides young children and pregnant women, non-pregnant women of reproductive age are considered as the high risk group because of blood loss via menstruation. Being ethnic minorities, the occurrence of anemia is probably higher than expected because anemia also links to inherited disorders of hemoglobin, thalassemia and hemoglobinopathies. To test whether our assumption is true, we therefore would like to determine the prevalence of anemia among female students of ethnic minorities as well as identify risk factors for anemia in this population. We anticipate that the findings provide basic information for further development of appropriate prevention program within this community.
Objective:
To determine the prevalence and risk factors for anemia among female students of ethnic minorities in Thai Nguyen province, Vietnam.
Procedure:
We will provide information sheet and explain the details of the project to all participants prior to enrolling the project.
If you agree to participate the project, you need to sign your name in the consent form.
This participation will take time about 15 to 30 minutes and has two steps.
Step I: Face-to-face interview using questionnaires (15-20 minutes)
We will ask you about demographic information as well as family history and medical history.
Step II: Blood collection (5-10 minutes)
We will take you blood sample (approximately 3 milliliters or half of a teaspoon) from venous blood vessel. This will done by laboratory staff of Thai Nguyen Institute of Hematology and Blood Transfusion
Your blood samples will be used for laboratory investigations as follows;
- Measure hemoglobin level to diagnose anemia and screen for thalassemia - In case of anemia, your blood sample will be investigated further for iron
status.
- All laboratory results will be sent to you via email or other channels as you wish.
If you agree, your left-over of blood sample will be kept at the Thai Nguyen Institute of Hematology and Blood Transfusion for further research work approved by the Institution Review Board (IRB) of Thailand and Vietnam.
If you do not agree, your left-over blood sample will be discarded.
Be noted that
The participation in this study is anonymous and voluntary.
You have the right to refuse without any consequences. If you do not want to participate in the study, you will be able to withdrawn at any time you want.
Risk: This participation will cause minimal disturbance to you or your feeling such as tighten at upper arm, red or purple spot on the point of the blood puncture area but this will not affect your health.
Benefits to participants: Feedback will be given to each participant regarding the written report of the result of the laboratory test as part of benefit for the participants. We also give you 30000 VND compensation for your time.
Confidentiality: All data will be kept confidential and anonymous. Your blood sample will be re-coded, so nobody can identify the participants.
Address of principal investigators
1. Ms. Hoa Thi Hong Hanh 13, Tan Thinh district, Thai Nguyen city, Vietnam Tel: 0912.468.596