Hiệu quả tăng cường vi chất vào thực phẩm đến tình trạng dinh dưỡng của học sinh tiểu học huyện nghĩa đàn tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING

MINISTRY OF HEALTH

NATIONAL INSTITUTE OF NUTRITION

NGUYEN DUC VINH

EFFECTIVENESS OF MICRONUTRIENT FOOD FORTIFICATION
ON NUTRITIONAL STATUS OF PRIMARY SCHOOL CHILDREN
IN NGHIA DAN DISTRICT

SPECIALIZATION : NUTRITION
CODE

: 9720401

Ph.D. THESIS SUMMARY

HA NOI - 2019


THE THESIS IS COMPLETED IN
NATIONAL INSTITUTE OF NUTRITION

THE SCIENTIFIC SUPERVISORS:
1. Prof. Dr. Le Thi Hop
2. Assoc. Prof. Dr. Bui Thi Nhung

Reviewer 1:
Reviewer 2:

The thesis will be defended in Thesis Committee at Institute level
in National Institute of Nutrition, Ha Noi
At……, on ..../…./2019

This thesis can be found at:
- National Library
- National Institute of Nutrition Library


ABBREVIATION LIST

BAZ

BMI for age Z-score

BMI

Body Mass Index

FFQ

Food Frequency Questionnaire

HAZ

Height for Age Z-score

Hb

Hemoglobin

MOH

Ministry of Health

NIN

National Institute of Nutrition

SEANUTS

The South East Asian Nutrition Surveys

RDA

Recommended Dietary Allowance

WAZ

Weight for Age Z-score

WHO

World Health Organization

WHZ

Weight for Height Z-score

UNICEF

The United Nations Children’s Fund


1

INTRODUCTION
Child malnutrition has been a public health problem in developing countries,
especially Asia nations, including Vietnam. Malnutrition problems at pre-school and
school ages include stunting, underweight and micronutrient deficiencies, which are
common in Vietnam. Over the last two decades, nutrition policies and programs
have contributed significantly in the improvement of nutritional status of under 5
year-old children. The underweight prevalence decreased from 19.9% to 14.1%
between 2008 and 2015. The period from 2008 to 2015 saw a decline in the
proportion of stunting children from 32.6% to 24.6%. However, the stunting
prevalence is still quite high compared to several countries in the region. Stunting is
closely related to micronutrient deficiencies. Results of the South East Asian
Nutrition Surveys (SEANUTS) investigation on Vietnamese children who had
micronutrient deficiencies showed that: The proportion of anemia in children aged 6
to 59 months was quite high at 23% and that in primary school age was 11.8%. The
prevalence of children with low iron stores (Ferritin<30 µg/L) was high at 28.8%.
The percentage of vitamin A deficiency was 7.7% and nearly half of children
(48.9%) had vitamin A limitation. The main reason of micronutrient deficiencies is
their diet that does not meet recommended dietary requirements. Some recent
studies showed that children’s diets, especially school age in rural, mountain areas
with difficult economic conditions, not only lacked of nutrients such as protein and
fat but also lacked of essential vitamins and minerals.
Nghia Dan district is one of indigent mountainous districts which has a high
prevalence of malnutrition in Nghe An province. According to statistic data in 2012,

Nghe An province had underweight prevalence at 20.2% and stunting prevalence at
30.8% that were higher than national figures. The district consists of 24 communes
and 1 town, with a very high poverty prevalence (21.6%). Using micronutrientfortified milk for preschool and primary school children to overcome stunting and
micronutrient deficiencies is one of the optimal solutions.
Assessing the effectiveness of school milk which is fortified with
micronutrients on improved child nutritional status, the research “Effectiveness of
micronutrient food fortification on nutritional status of primary school
children in Nghia Dan district” was conducted with 2 objectives:


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1. To describe nutritional status of preschool and primary school children in 6

communes of Nghia Dan district.
2. To evaluate the effectiveness of using micronutrient-fortified food to
improve nutritional status, anemia, zinc deficiency and vitamin A deficiency
of primary school children in Nghia Dan district after 5 months of
intervention.
News contributions of the thesis:
The thesis provided scientific evidence on the consumption of micronutrientsfortified milk on effectively improved nutritional and micronutrient status of
primary school children. The thesis results assist policy makers to develop
micronutrients-fortified milk standards for School Milk Program to improve
children stature by 2020, following Decision No.1340/QĐ-TTg dated July 8, 2016
by the Prime Minister.
Structure of thesis
The thesis has 123 pages, including: Introduction: 2 pages; Literature review:
33 pages; Method: 20 pages; Results: 31 pages; Discussions: 22 pages;
Conclusions: 2 pages; Recommendations: 1 page. The thesis includes 23 tables; 34
figures; 1 diagram; 88 references, in which 23 are in Vietnamese and 65 are in

English.

CHAPTER 1. LITERATURE REVIEW


3

1.1.

Nutritional status and micronutrient deficiencies of preschool and
primary school children

1.1.1. Nutritional status of children in the world
Malnutrition, especially stunning, is still a burden of disease leading to
children’s illness and death over the world, especially in developing countries in
Africa, South Asia and Southeast Asia, etc.
1.1.2. Nutritional status of Vietnamese children
Vietnam saw a continuous, rapid, and steady decrease of underweight
prevalence at 17.5% in 2010, at 15.3% in 2013 and at 13.8% 2016, an average
annual reduction of 0.6%. The percentage of stunting of children under 5 years old
declined from 59.7% in 1985 to 53.4% in 1990 and 36.5% in 2000. Besides, the
period from 2010 to 2016 saw a continuous fall from 29.3% to 24.3%. However,
stunting reduction is a challenge which is more difficult than reducing underweight.
Stunting situation is also still a public health problem in Vietnam. Survey results of
450 children aged 7 to 8 years old at 3 primary schools in Bac Ninh province (2005)
showed that the prevalence of stunting was very high about 32-40%. Study
outcomes of nutritional status in 6 provinces in 2011 illustrated the stunting
prevalence of aged 6-9 years old group and aged 9-11 years old group at 13.7% and
18.2%, respectively.
1.1.3. Micronutrient deficiencies in children

a. Global micronutrient deficiencies in children

It is estimated that 7.3% global burden diseases due to micronutrient
deficiencies with nearly 2 billion people having micronutrient deficiencies. Almost
people who have micronutrition deficiencies are living in the Third world countries
and lacking of many micronutrients at the same time. As of UNICEF’s statistics,
there were about 750 million children suffering from iron deficiency anaemia.
About one-third of children under 5 years old in developing countries is vitamin A
deficient. Southeast Asia, including Vietnam is the third most zinc-deficient region
in the world.
b. Micronutrient deficiencies in Vietnamese children
With the problem of stunting malnutrition, the percentage of children under 5
years of age with micronutrient deficiencies is high. Recent research results
(Nguyen Van Nhien et al. 2008) on preschoolers in rural Vietnam showed that the


4

prevalence of zinc, selenium, magnesium and copper deficiency was very high at
86.9%, 62.3%, 51.9% and 1.7%, respectively. The prevalence of anemia in children
under 5 years old in the whole country (2008) was 34.1%, especially in the Central
Highland 45.1%, and the South East 43.4%. Low serum vitamin A status is still
prevalent in rural and mountainous areas, accounting for 10.8%.
According to the survey results of National Institute of Nutrition (NIN) in
2014-2015 on subjects of children under 5 years of age, the prevalence of zinc
deficiency was very high: 50.9% of boys and 48.4% of girls in urban areas suffering
from zinc deficiency; 73.6% of boys and 69.3% of girls in rural areas suffering from
zinc deficiency; 84.1% of boys and 77.1% of girls in mountainous areas suffering
from zinc deficiency.
Micronutrient deficiencies in primary school children is also a public health

problem. Results of SEANUTS 2011 survey in 6 provinces showed that the
prevalence of deficiencies in primary school students ranged from 46-58%. Low
serum vitamin D prevalence ranged from 12-19%. The percentage of anemia was
11.8%, low iron stores was 28.8%. The proportion of vitamin A deficiency was
7.7%, and vitamin A limitation was 48.9%.
1.2. Vietnamese children’s diets
One of the most important causes of malnutrition of school aged children is
due to the lack of quantity and poor quality of the diet. According to the results of
the General Nutrition Survey (GNS) 2009-2010 of NIN, the iron intake of children
aged 2-5 reached about 70% of the recommended dietary allowance (RDA), the
zinc intake met 69%, iodine intake met about 35 %, zinc and vitamin A diet had a
biological activity of only about 32-35% and vitamin C diet post-processing
reached 65% RDA.
Survey of children’s diet aged 6-11 years in 6 provinces in 2011 showed that
dietary energy intake met 76%, calcium intake in the age group of 6-9 years reached
59% and in the age group of 9-11 years at 45% of RDA; iron in diet of 6-9 years old
group met 68% and age group 9-11 years old met 54%; The diet of vitamin A in the
age group of 6-9 years met 54% and the age group of 9-11 years met 43%, the
vitamin D intake of the age group of 6-9 years met only 18% and the age group of
9-11 years old met 13% of RDA.
Malnutrition and micronutrient deficiencies clearly affect the intellectual
development, children's learning ability, working ability towards adulthood. Child
malnutrition often results in very serious consequences.


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1.3. Solutions for malnutrition prevention and micronutrient deficiencies for
children
1.3.1. Micro-nutrient supplementation for children

There have been many studies on micronutrient supplementation for children
in Vietnam. In the study on supplementation of multiple micronutrients in oral form
in children from 6 to 12 months of age (Le Thi Hop et al.), the results showed that
the prevalence of stunting significantly decreased in the daily multi-nutrient
supplement group compared with the control group and the weekly multivitamin
supplement group. The research on the effect of micronutrient enriched milk and
normal milk on nutritional and micronutrient status of primary school children at
Yen Phong, Bac Ninh also illustrated that the prevalence of stunting and wasting
statistically reduced in multi-micronutrient fortified and normal milk groups, and
did not decline in the control group. The study of Truong Tuyet Mai and Nguyen
Thi Lam (2014) on the effectiveness of a product rich in amino acids and
micronutrients on stunted children showed effective reduction in stunting
prevalence, weight and height improvement, reduction of anemia prevalence, zinc
deficiency, iron deficiency in stunted children in Bac Giang.
1.3.2. Improvement of school meals
The school meal program for elementary school children has been piloted in
Hanoi, Da Nang and Hai Phong cities and has been expanding gradually in 63
provinces and cities: the initial results showed that 59% of students ate more
vegetables.
1.3.3. School milk program
School milk program has been implemented in many countries around the
world for many years. The most successful in the region is the School Milk Program
of China and Thailand. In Vietnam, these was an implementation of the School Milk
Program in Ba Ria - Vung Tau province, phase I at 82/82 communes/wards of the
province over 5 years. As a result, the malnutrition prevalence in children aged 3-5
years in the province decreased from 15.6% to 12% in just 5 years.


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CHAPTER 2. STUDY SUBJECTS AND METHODOLOGY
2.1. Study subjects, duration and venue
2.1.1. Study subjects
* Selecting subjects for assessing nutritional status of preschool children:
Inclusion criteria: Select all children aged 36-71 months enrolling at 6
kindergartens in 6 communes in Nghia Dan district.
Exclusion criteria: Children were out of the defined age and did not go to
school; their parents refused to participate in the study
* Selecting subjects for assessing nutritional status of primary school children:
Inclusion criteria: Select all children from 6-11 years old studying at primary
schools of 6 communes in Nghia Dan district.
Exclusion criteria: Children were out of the age and did not go to school; their
parents refused to participate in the study.
* Selecting subjects for assessing micronutrient status for an intervention school
and 2 control schools:
Inclusion criteria: Select all children from 6-11 years old with -3who were studying at the primary schools of 6 communes in Nghia Dan district.
Parents and families agreed to allow children to participate in the study.
Exclusion criteria: Children are milk intolerant, Children with digestive
disorders when drinking milk; Children with severe anemia: Hb<70 g / L; Children
with birth defects; Parents refused to let children to participate in the study.
2.1.2. Venue and duration of study
2.1.2.1. Study venue
Select on purpose 6 communes (Nghia Lam, Nghia Thang, Nghia Long, Nghia
Dan Town, Nghia Son, Nghia Yen) in Nghia Dan District, Nghe An Province.
2.1.2.2. Study duration: From November 2013 to December 2014.
2.2. Research Method
2.2.1. Research design: The study was conducted in 2 stages:
Stage 1: Cross-sectional study, assessing nutritional status of 951 kindergarten
children and 2,425 primary school children studying at preschools and primary

7

schools in 6 communes of Nghia Dan district. Based on the baseline results, 910
primary school children were selected to participate in the intervention.
Stage 2: Community intervention trial (randomized controlled trial, pre-and
post-evaluation) based on the number of subjects selected for stage 1: The
intervention group consisted of 455 students who received 180 ml of milk fortified
with micronutrients in 5 days/week for 5 months. The control group consisted of
455 students with normal diets.
6 primary schools in 6
communes

Evaluation before
intervention

4 intervention schools,
2 control schools

Measurement of height
and weight all students

910 primary school students of
6 communes

455 students of 5
communes intervened

Blood test and food survey in

120 Primary school children

455 students in Nghia
Long and Nghia Thang

- Drink 180ml of milk/day

- Normal diets

- Period: 5 months

- Period: 5 months

Blood test and food survey in
120 Primary school children

Evaluation after
intervention
Blood test and food survey
in 120 Primary school
children in Nghia Dan

Measurement of height and
weight of 910 primary school
children in 6 schools

Blood test and food survey in
120 Primary school children in
Nghia Long and Nghia Thang

Figure 2.1. Research diagram
2.2.2. Sample size
2.2.2.1. Sample size for assessing nutritional status of preschool and primary
school children
All kindergarten and primary school children of 12 schools participated in the
study.


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2.2.2.2. Sample size for evaluating the effectiveness of using micronutrients fortified
milk on the anthropometric indices of primary school children
Applying the sample size calculation for two independent groups:

Zαβ = 7.85; ES = (μ1 – μ2)/σ2
In which:
μ1 = -1.52 (average height Z-score of intervention group - after intervention)
μ2 = -1.27 (average height Z-score of control group - after intervention)
σ = 1.11658 (covariance, from 0.79 and 1.56)
The sample size for each study group was 342 students/group, anticipating
30% for dropping so 455 children for each group would be recruited.
2.2.2.3. Sample size for assessing the effectiveness of using micronutrients fortified
milk for the improvement of anemia, zinc deficiency and vitamin A deficiency of
primary school children
a. Calculate the sample size for assessing zinc status:
Applying the sample size calculation for interventional trial:
n

2C
( ES ) 2

In which:
- n is the required sample size
- C = (Zα + Zβ)2, C = 7.85 with α = 0.05 and β = 0.2 (power 80%)
- Effect Size ES = (µ1-µ2)/σ
- µ1-µ2 = 0.8 µmol/L average difference of zinc concentration between 2
groups after intervention of a previous study
- σ = 1.3 is Standard deviation of means
The sample size was 42 children/group.
b. Calculate sample size for serum Hb assessment:
Applying the sample size calculation for interventional trial:


9

n

2C
( ES ) 2

In which:
- n is the required sample size
- C= (Zα + Zβ)2, C = 7.85 with α = 0.05 and β = 0.2 (power 80%)
- Effect size ES = (µ1-µ2)/σ
- µ1-µ2 = 0.4 g/dL average difference of Hb level between 2 groups after
intervention of a previous study.
- σ = 0.76 is Standard deviation of means
The sample size was 56 children/group.
c. Calculation of sample size for serum vitamin A changes:
Applying the sample size calculation for interventional trial:

n

2C
( ES ) 2

In which:
- n is the required sample size
- C= (Zα + Zβ)2, C = 7.85 with α = 0.05 and β = 0.2 (power 80%)
- Effect Size = (µ1-µ2)/σ
- µ1-µ2 = 0.11µg/L average difference of serum retinol level between 2
groups after intervention of a previous study.
- σ = 0.3 is Standard deviation of means
The sample size was 116 children/group. The combination of all three
calculating the sample size results, the intervention study was 120 children/group x
2 groups = 240 children.
2.2.3. Sampling method
2.2.3.1. Selecting samples for assessing nutritional status of preschool and primary
school children
All kindergarten and primary school children of 12 schools participated in the
study.


10

2.2.3.2. Selecting samples for evaluating the effectiveness of using micronutrient
fortified milk for the anthropometric indices of primary school children.
- Step 1: After screening, students’ nutritional status was analyzed.
- Step 2: Based on the results, pair the subjects by HAZ.
- Step 3: Make a list of pairs that met the criteria to participate the study.

- Step 4: Invite parents of eligible children to meet and explain the research, if
they agreed, they would sign a consent form to secure 455 pairs.
2.2.3.3. Selecting samples for assessing the effectiveness of using micronutrients
fortified milk for the improvement of anemia, zinc deficiency and vitamin A
deficiency of primary students: Purposive sampling.
- Step 1: After screening, select all children with -3intervention school and 2 control schools.
- Step 2: From the list of children in 2 schools, pair by age, gender, nutritional
status (HAZ).
- Step 3: Make a list of pairs that met the criteria to participate in the study.
- Step 4: Invite parents of children who met the criteria to attend a training and
introduction workshop, if the parents agreed, they would sign a consent form to
secure 120 pairs (240 subjects).
2.2.4. Implementation of intervention
2.2.4.1. Grouping of study
- Control group: Have a normal diet.
- Intervention group: Take 180 ml of fortified milk, 5 days/week, drink for 5
months.
2.2.4.2. Implementation of intervention
- Training for teachers, health workers, and people in charge of school milk
program at schools.
- Distributing and monitoring drinking milk.
- Monitoring the implementation of intervention research: The main
supervisor in the intervention process was the PhD student. Besides, there was the
support of commune health stations, Department of Health, Department of
Education and Training, Nghe An Provincial Preventive Medicine Center, Nghia
Dan District and staff of NIN.


11

* The method of data collection:
Data collection (interviews, dietary surveys, anthropometric measurements
and blood sampling were conducted twice at the time of before intervention and at
the end of the intervention).
* Methods of lab test: Blood analysis was performed at the Department of
Micronutrient, NIN.
2.2.6. Result evaluation
2.2.6.1. Nutritional status evaluation
- Assess nutrition status of children aged 0-5 years old: Using reference
population and nutritional status classification according to WHO Growth Standard
2006.
- Assess the nutritional status of children aged 6-11 years old: Based on WHO
reference population (2007) to assess the nutritional status of children aged 6-11.
2.2.6.2. Diets
The child's diet is evaluated by food consumption, nutritional values of the
diet (dietary energy, diet balance, protein consumption, animal/plant protein ratio
and other nutrients), and the level of dietary response according to RDA for each
age based on the Table of RDA for Vietnamese in 2012.
2.2.6.3. Micronutrient deficiencies
- Anemia cut-off points: Children aged 6-59 months: Hb<11g / dL. Children
aged 5-11 years: Hb<11.5 g / dL.
- Zinc deficiency cut-off points: Children<10 years: Zinc serum level<9.9
µmol / L. Children>10 years of age: Boys with zinc serum level<11.3 µmol / L,
girls with zinc serum level<10.7µmol / L.
- Vitamin A deficiency cut-off points: serum retinol<0.7 µmol / L. Vitamin A
limitation when serum retinol ≥ 0.7 and<1.05 µmol/L.
2.2.7. Data analysis
Data collected were cleaned, checked, entered and analyzed by WHO Anthro
and SPSS 11.6. Before using statistical tests, variables were tested to bring about

normal distribution. The statistical tests in medicine were used.
- Crude intervention effectiveness ratio was calculated as:
H (%) = A-B/A x 100


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In which:
H is the effectiveness (%)
A is the incidence rate at the baseline
B is the incidence rate after 5 months of intervention
- Real intervention effectiveness ratio was calculated as:
Real intervention effectiveness = H1 - H2
In which:
H1 is the effectiveness ratio of intervention group
H2 the effectiveness ratio of control group
2.2.8. Methods to control errors
Anthropometric data: using the same data collectors for each time, with a
single scale and height ruler, at the same time in the morning (7-10 am). Strictly
follow study protocol for all investigators to avoid errors.
Biochemical and hematological tests have complied with the sampling and
storage procedures and the measurements have been analyzed by standardized
methods.
At the end of the investigation, the data were entered into computer. Daily
entering has helped reduce errors to the maximum. Randomly select 20% of the
samples to re-enter the second time, check the difference with the first time.
2.2.9. Research ethics
The outline was adopted by the Ethics Council and the Scientific Council of
NIN before implementation.
2.2.10. Research limitations

Intervention trial was implemented in primary schools, so interventions for
drinking milk did not last a long time enough (9 months to 1 year) to be able to assess a
significant change in height.


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CHAPTER 3. RESULTS
3.1. Nutritional status of preschool and primary school children in Nghia Dan
district
3.1.1. Nutritional status of preschool children in Nghia Dan district
A total of 951 children from 6 kindergartens in Nghia Long, Nghia Thang,
Nghia Lam, Nghia Son, Nghia Yen and Nghia Dan towns participated in the survey,
in which there are 498 boys and 453 girls, the average age of children participating
in the survey was 42.3 ± 12.6 months
Table 3.1. Anthropometric characteristics of preschoolers
Girls
Boys
Total
Indicators
AVG±SD
AVG±SD (n=498)
AVG±SD (n=951)
(n=453)
Age (months)
42.5±12.7
42.1±12.5
42.3±12.6
a
Weight (kg)

13.52.2
13.01.8
13.32.0
Height (cm)
93.66.5*
92.76.3
93.26.5
2
a
BMI (kg/m )
15.41.3
15.11.4
15.31.4
WAZ
-0.920.98
-0.940.90
-0.930.94
HAZ
-1.300.96
-1.230.91
-1.270.94
BAZ
-0.131.00**
-0.280.92
-0.200.97
WHZ
-0.291.00
-0.360.94
-0.320.97
a: p<0.05 when comparing between boys and girls (t-test)

Table 3.1 showed that the average weight of boys was 13.52.2 kg. The figure
for girls was lower (13.01.8 kg), with p<0.001. The average height of boys was
93.66.5 cm, which was higher than girls (92.76.3 cm), with p<0.05.
In general, boys had weight, height, BMI, BMI / age Z-Score that were significantly
higher than girls. However, there is no difference (p>0.05) in WAZ, HAZ and WHZ
between boys and girls.
Table 3.2. The percentage of malnutrition, overweight and obesity among
kindergarten children (%)
Indicators
Boys (n=498)
Girls (n=453)
Total (n=951)
Underweight (%)
61 (12.2)
56 (12.4)
117 (12.3)
Stunting (%)
114 (22.8)
91 (20.1)
205 (21.5)
Wasting (%)
14 (2.7)
14 (3.0)
28 (2.8)
Overweight (%)
5 (1.0)
5 (1.1)
10 (1.1)
Obesity (%)
5 (1.0)

1 (0.2)
6 (0.7)
* p<0.05 when comparing between boys and girls (2 test)


14

The proportion of underweight children in boys was 12.2% and in girls was
12.4% (Table 3.2). The stunting rate was quite high (in boys was 22.8% and in girls
was 20.1%), wasting rate in boys was 2.7% and in girls was 3.0%. The percentage
of overweight in boys is 1.0% and in girls is 1.1%. The figures for obesity in boys
was 1.0% and in girls was 0.2%. There was no statistically significant difference
when comparing the percentage of underweight, stunting, wasting, and overweight
and obesity between boys and girls.
3.1.2. Nutritional status of primary school children in Nghia Dan district
A total of 2,425 children of 6 primary schools in Nghia Long, Nghia Thang,
Nghia Lam, Nghia Son, Nghia Yen and Nghia Dan towns participated in the study,
including 1,257 boys and 1,168 girls.
Table 3.3. Anthropometric characteristics of primary school children
Indicators

Boys
Girls
Total
AVGSD (n=1257) AVGSD (n=1168) AVGSD (n=2425)
Age (months)
7.81.5
7.81.4
7.81.5
Weight (kg)

21.55.5
20.85.4
21.15.4
Height (cm)
120.28.7
119.39.3
119.79.0
2
BMI (kg/m )
14.51.9
14.61.7
14.51.9
WAZ
-1.201.11
-1.280.97
-1.241.05
HAZ
-1.210.89
-1.160.88
-1.190.89
BAZ
-0.900.93
-0.761.12*
-0.831.03
* p<0.05 when comparing between boys and girls (t-test)
The results in Table 3.3 showd that the average age of all participating primary
school children was 7.8 ± 1.5 years old. In general, there was no statistically
significant difference in weight, height, BMI, WAZ, HAZ, WHZ between boys and
girls. There was a statistically significant differences in BMI-for-age Z-Score
between boys and girls: girls had BMI-for-age Z-Score (-0.761.12) higher than

boys (-0. 900.93) with p<0.05.
Table 3.4. The percentage of malnutrition, overweight and obesity
among primary school children (%)
Indicators
Boys (n=1257)
Girls (n=1168)
Total (n=2425)
Stunting (%)
18.9
16.7
17.8
Wasting (%)
10.5
9.7
10.1
Overweight (%)
3.3
3.5
3.4
Obesity (%)
2.2
1.2
1.7
* p<0.05 when comparing between boys and girls (2 test)


15

The results of child nutrition assessment showed that stunting and wasting in
boys were higher than girls, but the difference was not statistically significant

(stunting malnutrition of boys was 18.9% and girls was 16.7%). The overweight
percentage in boys was 3.3% and in girls was 3.5%. There was no difference as the
figures for obesity in boys (2.2%) and in girls (1.2%) was the same.
3.2. The effect of using micronutrient fortified food on the change of child
anthropometric indices in Nghia Dan district
The total of 455 children of Nghia Dan primary school received milk fortified
with micronutrients (intervention group) and 455 children of 2 control schools
(primary school in Nghia Long and Nghia Thang communes) did not drink milk
(control group). After the intervention, there were 452 children from 4 intervention
schools and 445 children from 2 schools with qualified data on height and weight of
both assessments included in the results analysis.
Table 3.5. Comparison of anthropometric indices of children at T0
between the intervention and control group
Intervention group
Control group
Indicators
p
TB±SD (n=452)
TB±SD (n=445)
Weight (kg)
21.7±6.3
21.1±4.2
>0.05
Height (cm)
120.1±10.2
119.2±9.7
>0.05
2
BMI (kg/m )
14.8±1.8

14.4±1.3
>0.05
WAZ
-1.17±1.07
-1.27±0.86
>0.05
HAZ
-1.16±0.90
-1.26±0.87
>0.05
BAZ
-0.74±1.06
-0.96±0.87
>0.05
The results in Table 3.5 showed that most of the weight, height, BMI, WAZ,
HAZ, BAZ differences had no significantly statistical difference (p>0.05) between
intervention group and control group at time T0.

a: p<0.05 Comparison between 2 groups at T0 (2 test)


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Figure 3.1. The percentage of malnutrition, overweight and obesity of the
intervention group and control group at the time of before intervention (T0)
Figure 3.1 illustrated a comparison of the proportion of malnutrition,
overweight and obesity in the intervention and control groups at T0. There was no
significantly statistical difference (p>0.05) in underweight, stunting and wasting
between control group and intervention group. The prevalence of overweight and
obesity in both groups was very low and there was no statistically significant

difference.

a: p<0.05 compare in the same group on pre (T0)
and post- intervention (T5) (2 test)
Figure 3.2. The change in the percentage of malnutrition, overweight and obesity
in children at T5 compared to T0 of the intervention group
Figure 3.2 showed the change of nutritional status of the intervention group
at the time of T5 compared to the time of T0: after 5 months, nutritional status of
the children improved markedly: Underweight had the largest reduction (3.1%,
p<0.05, 2), the figures for stunting decreased by 1.8% and wasting decreased by
1.0%. Children who drank milk fortified with micronutrients did not increase the
risk of being overweight.


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p<0.05 comparing in the same group on previous (T0) and after intervention (T5)
(2 test)
Figure 3.3. Changing in the percentage of malnutrition, overweight and obesity
in children at T5 compared to T0 of the control group
Figure 3.3 showed that the change in nutritional status of the control group
was very little: the prevalence of underweight decreased by 1.4%, the percentage of
wasting decreased by 0.2%, the figure for overweight and obesity stayed the same.
Meanwhile, stunting prevalence increased by 0.9%.

a: p<0.05 Compare between 2 groups at T5 (2 test)
Figure 3.4. The percentage of malnutrition, overweight and obesity of the
intervention group and control group at the time of post-intervention (T5)
Figure 3.4 showed that after 5 months of intervention, the percentage of
underweight and stunting of the intervention group were lower than the control

group with (p<0.05). However, there was no statistically significant difference
(p>0.05) in the proportion of wasting, overweight and obesity between the control
group and intervention group at T5.
3.3. Assessing the effectiveness of micronutrients fortified food on the
improvement of micronutrient status: Anemia, zinc deficiency, vitamin A
deficiency of primary school student at risk of stunting (HAZ<-1 SD)
Table 3.6. Comparison of micronutrient contents
between intervention group and control group at T0
Intervention group
Control group
AVG SD (n= 105)
AVG SD (n=119)
Hb (g/dL)
12.1±1.1
12.1±0.9
Vitamin A (µmol/L)
1.12±0.26
1.16±0.57
Zinc (µmol/L)
9.45±1.54
9.50±2.34
p<0.05 comparing control group and intervention group (t-test)
Indicators

p
>0.05
>0.05
>0.05

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Table 3.6 illustrated there was no difference in vitamin A, Hb, Zinc between
intervention group and control group at T0.


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Table 3.7. Changes of micronutrient contents of primary school children
in intervention group
T0
T5
p
AVGSD (n = 105) AVG SD (n = 105)
Hb (g/dL)
12.1±1.1
12.3±0.7
>0.05
Vitamin A (µmol/L)
1.12±0.26
1.16±0.31
>0.05
Zinc (µmol/L)
9.45±1.54
10.25±1.79
< 0.05
p<0.05 Comparing the same group pre and post-intervention (Paired t-test)
Indicators

The results in Table 3.7 showed that Hb and vitamin A level of intervention

group had no difference (p>0.05) between T5 and T0. However, zinc level increased
significantly (p<0.05) compared to the time before intervention.
Table 3.8. Changes of micronutrient contents of primary school children
in control group
T0
T5
Indicators
p
AVG SD (n = 119) AVG SD (n = 119)
Hb (g/dL)
12.1±0.9
12.0±1.1
>0.05
Vitamin A (µmol/L)
1.16±0.57
1.15±0.53
>0.05
Zinc (µmol/L)
9.50±2.34
9.55±1.71
>0.05
p<0.05 Comparing the same group pre and post-intervention (Paired t-test)
Table 3.8 showed that Hb, vitamin A, zinc level of control group at T5 had no
statistically significant difference (p>0.05) compared to T0.

Figure 3.5. The effectiveness of intervention on improving anemia
of primary school children with HAZ<- 1 SD in the intervention group
Figure 3.5 showed the effectiveness of the intervention on improving anemia
of primary school children at risk of stunting and stunting: After 5 months of
intervention, the percentage of anemia in the intervention group decreased by 7.6%.

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p<0.05 Comparing between 2 groups at the same time (2 test)
Figure 3.6. The effectiveness of intervention on improving vitamin A deficiency
status of primary school children with HAZ<- 1 SD
of intervention and control groups
Results of improvement of vitamin A deficiency of 2 groups were shown in
Figure 3.6. Similar to anemia, the percentage of vitamin A deficiency in the
intervention group decreased more and statistically significant difference (p<0.05)
compared to the control group (intervention group reduced 4.7%, control group
increased 0.9%). There was a statistically significant difference in the proportion of
vitamin A deficiency at T5 between the intervention group and the control group.


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CHAPTER 4. DISCUSSION
4.1. Nutritional status of preschool and primary school children in 6
kindergartens and 6 primary schools in Nghia Dan district
4.1.1. Nutritional status of preschool children in 6 kindergartens in Nghia Dan
district
Survey in Nghia Dan showed that boys had average weight, height, BMI, ZScore BMI/age that were significantly higher those of girls. There were no
statistically significant differences in WAZ, HAZ among boys and girls.
Underweight prevalence in boys was 12.2% and in girls was 12.4%, the total
was 12.3%. Stunting prevalence was quite high with 22.8% in boys and 20.1% in
girls of the total 21.5%. Wasting prevalence was as low as 2.7% in boys and 3.0% in
girls. Overweight/obesity was low too, around 0.2 to 1.1%. There were no statistical
differences in under nutrition and overweight/obesity prevalence among 2 sexes.

Average weight and height of preschool children were both lower than those of the
WHO growth standard 2006. Underweight, stunting and wasting prevalence of
preschool children in Nghia Dan were poorer than those of Vietnamese children
under 5 in 2013 nation-wide.
Stunting prevalence of children under 5 had reduced from 59.7% in 1985 to
53.4% in 1990 and 36.5% in 2000. In 2005, this prevalence was 29.6% (NCHS
reference). Data from National Institute of Nutrition showed the increase to 31.9%
in 2009, the reduction to 29.3% in 2010 (due to switching to new WHO growth
standard 2006 since 2006) and it continued to reduce to 26.7% in 2012. Reduction
of stunting is quite challenging, more difficult than reduction of underweight.
A survey on micronutrient deficiencies in preschool children (3 to 5 years old)
in Srilanka showed that anemia prevalence (Hb<110 g/L) was 34% in boys and 33%
in girls, total of 33.5%. In anemic children, 7% of boys and 15% of girls had iron
deficiency (serum ferritin<15 mg/L). Meanwhile, zinc deficiency (serum zinc<9.95
mol/L) happened in 57% boys and 50% girls. Vitamin D deficiency (serum
vitamin D<35 mol/L) happened in 26% boys and 25% girls.
4.1.2. Nutritional status of primary school children in 6 primary schools in Nghia
Dan district
The survey on 2,425 primary school children of 6 communes in Nghia Dan
district showed that average age of the subjects was 7.8±1.5 years. Average weight


22

of boys was 21.55.5 kg and that of girls was 20.85.4 kg. Average height of boys
and girls was 120.28.7 cm and 119.39.3 cm. Average BMI of boys and girls was
14.51.9 kg/m2 and 14.61.7 kg/m2, respectively. In general, there were no
statistical differences in weight, height, BMI, WAZ, HAZ, WHZ between boys and
girls. Only BMI/Age Z-scores were statistical difference between boys and girls.
The prevalence of stunting in boys was 18.9% and in girls was 16.7%, the

total of both sexes was 17.8%, higher than the prevalence of stunting of children
aged 6 -9 years of 6 provinces of Vietnam (13.7%, SEANUTS survey in 2011). The
prevalence of wasting in boys was 10.5% and in girls was 9.7%, the overall
prevalence was 10.1%, 3 times higher than preschool children. The overweight
prevalence in boys was 3.3% and in girls was 3.5%, the general prevalence was
3.4%. The prevalence of obesity in boys was 2.2% and in girls was 1.2%, the
overall prevalence was 1.7%. There was no statistically significant difference when
comparing the prevalence of underweight, stunting, wasting and overweight,
obesity among boys and girls.
According to the nutrition survey in 6 provinces in Vietnam in 2011, the
stunting prevalence of children aged 6-11 was 13.7% and of children 9-12 years old
was 18.2%. A survey of 450 children aged 7-8 years at 3 primary schools in Bac
Ninh in 2005 showed a high prevalence of stunting malnutrition: 32-40%. That
survey in 6 provinces in Vietnam in 2011 also showed that the stunting prevalence
of children aged 6-9 was 13.7% and aged 9-11 was 18.2%. In addition, there was a
rapid increase in overweight and obesity, especially in large cities: a 2011 survey at
schools in the inner districts of Hanoi showed the prevalence of overweight in
children had increased from 7.9% in 2003 to 40.7% in 2011
In Cambodia, malnutrition, anaemia, iron deficiency, zinc deficiency, iodine
and vitamin A deficiency are risk factors for cognitive impairment at school age (616 years) in this country. The development and implementation of nutrition
improvement programs at early aged and school aged children could be the optimal
solution to improve children's cognitive abilities.
4.2. The intervention of micronutrient fortified food in primary school children
in 5 months showed the effectiveness on improved nutritional status.
As recommended by WHO, milk is one of the essential food groups in
children's daily meals. However, milk has the disadvantage that the proportion of
micronutrients is not high, so micronutrient fortification in milk helps overcome this