epidemiological characteristics of asthma in 13-14-year-old children and the effects of health education intervention in two districts of hanoi

MINISTRY OF EDUCATION AND TRAINING
MINISTRY OF HEALTH
THE NATIONAL INSTITUTE OF HYGIENE AND EPIDEMIOLOGY
***




ĐANG HUONG GIANG

EPIDEMIOLOGICAL CHARACTERISTICS OF ASTHMA
IN 13-14-YEAR-OLD CHILDREN AND THE EFFECTS OF
HEALTH EDUCATION INTERVENTION IN TWO
DISTRICTS OF HANOI


Science: Epidemiology
Code: 62 72 01 17

SUMMARY OF THE DOCTORAL DISSERTATION








HA NOI - 2014

The project was completed at the
National Institute of Hygiene and Epidemiology

The scientific advisors:
1. Prof. Nguyen Tien Dung
2. Prof. Đang Đuc Anh

Reviewer 1:
Reviewer 2:
Reviewer 3:


The dissertation had defended at the meeting hall of the National
Institute of Hygiene and Epidemiology.

In …………………


The dissertation is available at:
1. The National Library
2. The National Institute of Hygiene and Epidemiology





LIST OF THE PUBLICATIONS BY THE
AUTHORS RELATED TO THE DISSERTATION


1. Đang Huong Giang, Nguyen Tien Dung, Đang Đuc Anh (2011),
"Quality of life of children with asthma in Bach Mai and Saint Paul
hospitals, Hanoi in 2010-2011", Journal of preventive Medicine, No
7(125), Set XXI, pp. 22-27.
2. Đang Huong Giang, Nguyen Tien Dung, Đang Đuc Anh (2014),
"The status of asthma knowledge among 13-14-year-old children

with asthma at Thanh Xuan and Long Bien districts in Hanoi, 2012",
Journal of preventive Medicine, No 1(149), Set XXIV, pp. 58-63.
3. Đang Huong Giang, Nguyen Tien Dung, Đang Đuc Anh (2014),
"Effectiveness of school-based education program for 13-14-year-old
schoolchildren with asthma at Thanh Xuan and Long Bien districts in
Hanoi, 2012-2013", Journal of preventive Medicine, No 1(149), Set
XXIV, pp. 64-70.








1. Introduction
Asthma is a common chronic respiratory disease, affecting people of
all ages particularly of childhood. The predominant symptoms such as
wheezing, cough, breathlessness and chest tightness are intermittent, more
severe at night and early morning, affecting on daily life and sometimes
fatal. The prevalence and morbidity rates due to asthma are rising in many
areas in the world.
Although there are no cure for asthma but we can control disease and
maintain control it for a long period of time by conducting health education
programs.
In Viet Nam, the statistics of the national survey demonstrated that
the prevalence associated with asthma in adults was 4.1%, 64.9% among
patients visited emergency departments, more than 80% of asthmatic
children under fifteen has never been treated with preventor while some
studies revealed that knowledge of parents on asthma was impaired.

Studying epidemiological characteristics of asthma and carrying out
the interventions in communities to manage asthma and to improve quality
of life of patients is practical and essential research. Thus, we conducted
the study "Epidemiological characteristics of asthma in 13-14-year-old
children and the effects of educational intervention at two districts in Ha
Noi". The study objectives were
1. To describe some epidemiological characteristics of asthma in 13-
14-year-old children at Thanh Xuan and Long Bien districts in Ha
Noi in 2012.
2. To assess the effeciveness of educational intervention in two
researched districts
2. New scientific contributions

- The study defined the prevalences of diagnosed asthma in 13-14-year-old
children at two districts in Ha Noi and discribed some common trigger
factors.
- This study is the first for establishing the modern asthma management for
schoolchildren and assessing the effects of health education intervention
with outcomes: asthma status, school absenteeism, knowledge about
asthma and quality of life of the children.
3. Practical value of the study
-The results of study about the prevalences of asthma in children helped
physicians realize the popularity of asthma in communities. Furthermore,
the information about the asthmatic trigger factors permitted doctors choose
the suitable intervention to control those factors.
- The study affirmed the effects of health education intervention on
controlling asthma symptoms, school absenteeinsm due to asthma and
improving the asthmatic knowledge and demonstrated that this method
could be applied in many schools.
4. The structure of the dissertation: The dissertation consists of 126

pages including, introduction 2 pages, literature review 32 pages, objectives
and methods 19 pages, results 27 pages; discussion 29 pages, conclusions 2
pages and recommendation 1 page. There are 23 tables, 13 charts and 3
pictures, 118 references including 25 in Vietnamese and 93 in English.
Chapter 1. Literature review
1.1 Epidemiology of asthma: There are three methods of identifying
cases of asthma that being used commonly in epidemiological researchs in
the world: asking directly patients for self-reporting of the asthma
dianognosis and/or the most common sypmtoms of asthma such as
wheezing and assessment of bronchial reactivity of the airway to exercise.
1.1.1 Epidemiology of asthma in the world
1.1.1.1 Prevalence
- The prevalence of asthma in childhood: the prevalences of 13-14-year-
old children being diagnosed asthma varied between 1.6% to 28.2% and

they were lower than having wheezing. In 6-7-year-old children the
prevalences of being diagnosed asthma ranged from 1.4% to 27.2%. The
difference of the prevalences of wheezing and asthma between countries is
larger than within country.
- The prevalence of asthma in adulthood: in 64 coutries in adults aged
18-99- years the prevalence of doctor-diagnosed asthma was lowest in Viet
Nam (1.8%) and highest in Australia (32.2%). According to the World
Health Organization, the variation in the prevalence of asthma between
different countries is 21-fold.
1.1.1.2 Factors influencing the prevalence of asthma.
- Environmental factors: The indoor factors (fungi, domestic dust, insects,
cockroaches, tobacco smoke) and outdoor factors (air pollution, dust and
smoke) influence the prevalences of asthma. Some jobs associated with
higher risk for occupational asthma are farming work, painting, cleaning
solution and plastic manufacturing.

- Host factors: the factors such as sex, weight, atopy have been considered
as asthma risk factors. Male sex is a risk factor for asthma in childhood,
and people who have BMI≥25 seem to have asthma with 1.51 fold higher
than those with a average-weighted. The risk of asthma among children
whose parents had atopic diseases are 3.29 times higher than other children.
1.1.1.3 Times trends of asthma: In United State, Australia, some
European developed countries (Finland, Sweeden, Newziland, the UK) and
Asian countries such as Hongkong, Singapore, Thailand the prevalences of
asthma and wheezing are rising.
1.1.1.4 Incidence: Currently, there are no methods to measure the
incidence of asthma accurately. In the UK, the incident of asthma was high
(136.6/10.000/year), The American statistics showed that incidence of
asthma was 3.8/1000/year, during one year new onset rates were highest in
Auturm and Winter.
1.1.1.5 Asthma mortality: in 2000 mortality among American patients
hospitalized for asthma were 0.5%. In some countries such as Switzerland,

Portugal and Japan the reduction in asthma mortality have appeared by
increasing use of inhaled corticoides
1.1.2 Epidemiology of asthma in Viet Nam
In our country statistics data on prevalence and mortality of asthma
is lack. In 2003, the prevalence of asthma among children in Ha Noi was
12.56% in urban areas and 7.52% in rural areas. In 2007, the prevalence of
diagnosed asthma among 13-14-year-old children in Can Tho was 1.4%.
The prevalence of asthma in Vietnamese adults was 4.1%; the rates of
asthma in male was higher in female. However, Viet Nam has ackowledged
that the rates of asthma mortality were increasing.
1.2 Asthma and wheezing symptom
1.2.1 Asthma
1.2.1.1 Definition: Asthma is a chronic inflammatory disorder of the

airway in which many cells and cellular elements play a role. The chronic
inflammation is associated with airway hyperresponsiveness that leads to
recurrent episodes of wheezing, breathlessness, chest tightness, and
coughing, particularly at night or in the early morning. These episodes are
usually associated with widespread, but variable, airflow obstruction within
the lung that is often reversible either spontaneously or with treatment.
1.2.1.2 Mechanisms of asthma: there are three main disease progressions
of asthma: airway chronic inflammation, airway narrowing and airway
hyperresponsiveness
1.2.1.3 Causal and risk factors: including host factors and environmental
factors
- Host factors consist of genetic, obesity, sex and age.
- Environmental factors consist of allergens (domestic allergens, furred
animals, pollen, fungi), respiratory inflammation, air pollution, tobacco
smoke, food, drugs.
- Another factors: endocrin, climate, exercise, stress.
1.2.1.6 Asthma treatments: In GINA asthma treatment steps the education
is the first.

1.3 The role of education in asthma preventional strategy: The experts
evaluated that asthma education is a cheap and effective intervention in
asthma management and prevention.
1.3.1 The activities of education: multiple educational methods have been
used such as exchange information, discussion, asthma consultant, asthma
clubs.
1.3.2 Effectiveness of education interventions: There have been many
studies about effectiveness of education on asthma.
- The effectiveness on asthma symptoms: education intervention for parents
reduced visits to emergency room, admissions to hospital and attacks of
asthma compared with the control group.

- The effectiveness on school absenteeism: education for primary
schoolchildren eliminated days of school missed due to asthma.
- The effectiveness on keeping well treatment: education helped patients to
realize the significance and essential of follow-up treatment, therefore this
could reduce the number of children who were unschedules doctors visits.
- The effectiveness on children’s knowledge of asthma: education in the
schools improved schoolchildren’s knowledge, using inhaler skill, helped
children to choose activity and increased asthmatic knowledge of
caregivers.
- The effectiveness on quality of life: asthma impairs the quality of life of
the patients. According to researchers, the effects of education on patients'
quality of life were not clear and this should be investigated in more
studies.

Chapter 2. RESEARCH METHODOLOGY
Sample and setting
- The sample for objective 1: The 13-14-year-old schoolchildren have been
studying 7-8th grade from the secondary schools at two districts Thanh
Xuan and Long Bien.

- The sample for objective 2: the asthmatic children of two districts Thanh
Xuan and Long Bien who participated in the characteristic epidemiological
study.
- Inclusion criteria: The children who enrolled in the intervention study
were asthmatic children based on the criteria of the International study of
asthma and allergy in childhood (ISAAC), the physician-diagnosed asthma.
- Exclusion criteria
+ The children without agreed to participate in the study.
+ The children transfered to another school which is out side of study's
setting

- The setting: the study was conducted at two districts Thanh Xuân and
Long Bien in Ha Noi. Two districts were chosen purposively because of
differences in geography and level of urbanization
2.2 Methodology
2.2.1 Study designs
- Cross-sectional survey.
- Longitudinal intervention community study with control group.
2.2.2 Sample sizes and sampling methods
2.2.2.1 Sample size and sampling method for objective 1
- Sample size: using the formula for estimating population proportion

 
2
2
2/1
)1(


p
pp
zn




Where: p - prevalence of diagnosed-asthma among 13-14-year-old children
estimated from the previous study=2.6%; α - significance level was chosen
= 0.05%, z- corresponding to 95% confidence level = 1.96, ε- disired precision
was chosen = 0.22. A required minimum sample size was 2973.4 children.
In each district at least 3000 children would have enrolled.

- Sampling method: purposive and simple random sampling. The
sampling based on instruction of ISAAC, in each geographical area the
sampling unit will be a school.
Step 1: districts Thanh Xuan and Long Bien were chosen purposively
Step 2: choosing the schools randomly by making a table sample of each
districts, the schools were selected in study by randomly drawing school
by school untill there were at least 3000 13-14-year-old children.
Step 3: whole 13-14-year-old children in selected schools were enrolled in
study. Actually, in each district 8 schools were selected.
2.2.2.1 Sample sizes and sampling methods for objective 2
- Sample sizes: there were 4 outcomes in the study: asthma status including
day and night symptoms, asthma control test score; school absences;
knowledge of asthma and quality of life. Untill now there has been no study
knowledge of asthma among schoolchildren so this study used three
outcomes including school absences, asthma control test score and quality
of life score to calculate sample size for intervention objective.
+ Outcome is school absences, using the formula estimating the difference
between two proportions.

2
21
2211
2
,
)(
)1()1((
pp
ppppz
n







Where: n is the minimum sample size in each of intervention and control
groups; p
1
- proportion of children being abcent from school from the
previous study =38.5%; p
2
- proportion of children being absent from
school was expected the result to be 18.5%; α- type I error was chosen at
0.05% corresponding to significant level 95%; β - type II error was chosen
at 0.2% corresponding to power 80%, we have z
α,β
= 7.9. Hence, a required
minimum sample size was 77 children. Providing for 10% of drop-out study
participants sample size was 85 children in each group.

+ Outcome is quality of life and asthma control test score, using the
formula estimating the difference between two means.

2
21
22
)(
)(2







zz
n


Where: n is the minimum sample size in each of the two groups; δ -
variance; μ
1
- μ
2
-the expected difference between two means of two
groups.
- Sample size for quality of life: δ - variance from the previous study was
1.25; with expecting to find out the difference between means of quality of
life scores was 0.5, thus we chosed μ
1
– μ
2
= 0.5; α = 0.05 corresponding to
z
α
=1.96 and β = 0.2 corresponding to z
β
=0.84. Thus, n=98 children.
Providing for 10% of drop-out study participants sample size was 108
children in each group

- Sample size for asthma control test score: δ - variance from the previous
study was 3.2; with expecting to find out the difference between means of
asthma control test score was 1.4, thus we chosed μ
1
– μ
2
= 1.4; α = 0.05
corresponding to z
α
=1.96 and β = 0. 2 corresponding to z
β
=0.84. Hence,
n=82 children. Providing for 10% of drop-out study participants sample size
was 91 children in each group
Combined the results of calculating sample size, a sample of 108 children
should be studied in each of two groups.
- Sampling methods: purposively sampling.
+ Choosing the subjects for intervention study: Actually, 133 children with
diagnosed asthma in Thanh Xuân district and 126 children with diagnosed
asthma were found out from cross-sectional study, these children were
enrolled in the intervention study and followed in one year.
+ Assignment to groups: purposively selected Thanh Xuan district in the
intervention group and Long Bien district in the control group. Thus, 126
children with diagnosed asthma in Long Bien district belonged to the

control group and 133 children with diagnosed asthma in Thanh Xuan
district belonged to the intervention group.
2.2.3 Study contents
2.2.3.1 Study contents in objective 1
- Study variables: prevalences of asthma, wheezing, the risk factors,

characteristics of indoor and outdoor
- Instruments: used the ISAAC questionnaire including 8 questions in
Vietnamese.
2.2.3.2 Study contents in objective 2
- Intervention contents
+ Selected intervention district was Thanh Xuan. The intervention was
performed in schools by healthcares and teachers of the schools who have
exprienced in the training course about asthma. The control group was
Long Bien, the asthmatic children were received the traditional health care
and would received the intervention of the study one year later. The
materials of intervention entailed booklets for children and for schools'
healthcares which containing core contents about asthma and how to
manage the asthma. The education program consisted of 4 sessions lasting
40 minute each, provided at 1 month intervals from September to
December in 2012.
- Variables: asthma status, school absence, asthma knowledge and quality
of life.
- Isntruments
+ Knowledge questionnaire consisted of 20 questions
+ Asthma control test for 12 year old and over contained 5 statements.
+ Quality of life questionnaire comprised 23 items in 3 domains: activity
limitation, symptoms and emotional function.
- Procedure
+ In September 2012 (t
0
) children were surveyed knowledge, asthma
control test, quality of life. This was baseline information.

+ In September, October and November children were attended educational
sessions three times, 1 month interval. The information from these surveys

was used to guide the chilren how to evaluate and monitor asthma
themselves.
+ In December 2012 and May, September 2013 (t
1
, t
2
and t
3
) children were
surveyed knowledge, asthma control test, quality of life. This was posttest
intervention information
2.2.5 Statistical methods: Statistical analysis was performed using Epidata
3.1, and Stata.11.1. We performed statisticcal test such as chi-square test,
Fisher's exact test, Mann-Whitney test and Generalized Estimating
Equations.

Chapter 3. RESULTS
6701 schoolchildren from two districts were surveyed.
Epidemiological characteristics of asthma
Table 3.3 District distribution of children with diagnosed asthma
Characteristics
Total
Thanh Xuân
district
(n=3118)
Long Biên
district
(n=3583)
p
value

test χ
2


n
%
n
%
n
%
Diagnosed
asthma
260
3.9
134
4.3
126
3.5
0.1
Table 3.3. shows that the prevalence of children with diagnosed asthma in
Thanh Xuan district was as much as in Long Bien district with p>0.05.
Table 3.4 Sex distribution of children with diagnosed asthma
Characteristics
Male
(n=3485)
Female
(n=3216)
p value
test χ
2

n
%
n
%
Diagnosed asthma
154
4.4
106
3.3
0.02
Table 3.4. shows that the prevalence of children with diagnosed asthma in
males was significantly higher than females with p<0.05.

Table 3.6 District distribution of children with wheezing
Characteristics
Thanh Xuân
(n=3118)
Long Biên
(n=3583)
p value
test χ
2

n
%
n
%
Current wheezing
248

8.0
369
10.3
0.001
Severe wheezing
119
3.8
138
3.9
0.94
Table 3.6. shows that compared with Thanh Xuan district, the prevalence of
children with current wheezing in Long Bien district was greater with
p<0.05.
Table 3.10. Some characteristical outdoors of asthmatic children
Characteristics
Thanh Xuân
district
(n=133)
Long Biên
district
(n=126)
P
value
χ
2
test
n
rate
%
n

rate %
House was influenced by
smoke outside

47

35.6

64

50.8

0.01
School was influenced by
dust, smoke and chemical
odour

58

43.6

37

29.4

0.02
Table 3.10 shows that according to the children in Long Bien their houses
were influenced by smoke outside more than in Thanh Xuan, conversely,
the children in Thanh Xuan believed that smoke, dust and chemical odour
have impacted on their schools more than in Long Bien (p<0.05)

Table 3.11 The asthmatic trigger factors of children in the last 12 months

Factors
Total
(n=259)
Thanh Xuân
district
(n=133)
Long Biên
district
(n=126)
n
rate %
n
rate %
n
rate %
Climate change
146
56.4
75
56.4
71
56.3
Cold
69
26.6
37
27.8
32

25.4
Exercise
65
25.1
31
23.3
34
27.0
Tobacco smoke
63
24.3
38
28.6
25
19.8

Table 3.10 shows that the common asthmatic trigger factors of children in
two districts were climate change, cold and exercise.
3.3 The effectiveness of educational intervention.
Selected Thanh Xuan district in the intervention group and Long
Bien in the control group. In September 2013 there were 7 children in two
districts transfering their schools to another ones.
3.3.1 Characteristics of children with asthma at baseline
- Characteristics of asthma status
Table 3.13 Percentage of characteristics of asthma status at baseline
(t
0
)

Characteristics

Intervention
district
(n=133)
Control district
(n=126)
P value
χ
2
test
n
rate %
n
rate %
Day-time symptoms

34
25.6
45
35.7
0.08
Night-time symptoms
20
15.0
26
20.6
0.24
Table 3.13 shows that there was no difference on the number of chidren
having day-time and night-time symptoms between two districts with
p>0.05
Table 3.13 Asthma control test of children at baseline (t

0
)
Characteristics
Intervention
district
(n=133)
Control
district
(n=126)
P
value

Asthma control test score
(
x
± SD)

23.1 ± 2.9
22.5 ± 3.3
0.11
Percentage of children with
well-controlled asthma
88.7
86.5
0.12
Mann-Whitney test calculations for the difference between means of two
groups and Chi-square calculations for the difference between two groups
on proportion.

Data in table 3.14 demonstrates similarities of asthma control test between

two districts.
- Characteristics of school absences
Table 3.15 Percentage of children being absent from school at baseline
(t
0
)
Characteristics
Intervention
district
(n=133)
Control
district
(n=126)
P value
χ
2
test
n
rate %
n
rate
%
Being absent from
school
15
11.3
11
8.7
0.32
Data in table 3.15 demonstrates similarities of percentage of children being

absent from school between Thanh Xuan and Long Bien districts.
- Characteristics of knowledge on asthma
Table 3.18 Asthma knowledge of the children at baseline (t
0
)
Knowledge
Intervention
district
(n=133)
Control
district
(n=126)
p value

Knowledge score
(
x
± SD)
8.0 ± 4.0
8.3 ± 3.6
0.52
Percentage of children
having a good level of
understanding asthma
2.3
0.8
0.33
Mann-Whitney test calculations for the difference between means of two
groups and Chi-square calculations for the difference between two groups
on proportion.

Table 3.18 shows no significant differences between two districts for
asthma knowledge of chidren with p>0.05

- Characteristics of quality of life
Table 3.19 Quality of life of the children at baseline (t
0
)
Quality of life
Intervention
district
(n=133)
Control
district
(n=126)
P value
(Mann
Whitney
test)
Activity limitation
(
x
± SD)
30.3 ± 5.9
29.9 ± 5.5
0.23
Symptoms (
x
± SD)
60.5 ± 11.2
60.9 ± 9.9

0.72
Emotions fuction
(
x
± SD)
49.4 ± 9.0
50.7 ± 6.9
0.93
Quality of life total
score (
x
± SD)
140.2 ± 23.8
141.5 ± 20.3
0.76
Data in table 3.19 demonstrates that no significant differences were found
between two districts on quality of life in subscales and total scale at
baseline.
3.3.2 Effectiveness of educational intervention
- Effectiveness on asthma status

0
10
20
30
40
50
t0 September t1 December t2 May t3 September
intervention district
control district

P= 0.001
+++
P= 0.08
+
P= 0.01
+
P=0.08
+
P= 0.001
+
percentage of children having day symptoms
Times
+
p from χ
2
test;
+++
p from generalized estimating equations


Chart 3.7 Effectiveness of education on percentage of children having
day-time symptoms

0
5
10
15
20
25

30
t0 September t1 December t2 May t3 September
intervention district
control district

Chart 3.8 Effectiveness of education on percentage of children having
night-time symptoms
Chart 3.7 and 3.8 show that there were significant diminution in day-time
and night-time symptoms over time in the intervention district compared to
the control district with p<0.05
Table 3.20 Effectiveness of education on percentage children with well-
controlled asthma
Percentage of children
with well-controlled
asthma
Times
Intervention
district
n %
Control
district

n %
P value
(χ
2
test)
t
0 September
118

88.7
109
86.5
0.59
t
1 December
128
96.2
110
87.3
0.01
t
2 May
125
94.0
113
89.7
0.21
t
3 September
123
94.6
108
88.5
0.08
+++
p

0.02
+++

p: Generalized estimating equations
Table 3.20 shows that in the intervention district the percentage of children
with well-controlled asthma increased over time more significantly than it
in the control district with p<0.05
- Effectiveness on absence from school
P=0.001
+++
P=0.2
4
+
P=0.001
+
P=0.02
+
P=0.1
+
percentage of children having hight symptoms

Times
+
p from χ
2
test;
+++
p from generalized estimating equations


Table 3.21 Effectiveness of education on percentage of children being
absent from school
Percentage of children

being absent from
school
Times
Intervention
district
n %
Control
district

n %
P value
(χ
2
test)
t
0 September

15
11.3
11
8.7
0.32
t
1 December
4
3.0
11
8.7
0.04
t

2 May
5
3.8
13
10.3
0.03
t
3 September
3
2.3
12
9.8
0.01
+++
p
0.02
+++
p: Generalized estimating equations
Table 3.21 shows that in the intervention district the percentage of children
being absent from school decreased over time. The decrease was significant
compaired to the control district with p<0.05
- Effectiveness on asthma knowledge
4
8
12
16
20
t0 September t1 December t2 May t3 September
intervention district control district

+++
p: Generalized estimating equations
Chart 3.10 Effectiveness of education on knowledge score
Chart 3.10 shows that children's knowledge score in the intervention
district increased over time more significantly than in the control district
with p<0.05
- Effectiveness on quality of life
p=0.0001
+++

knowledge score
Lần


56
58
60
62
64
66
68
70
t0 September t1 December t2 May t3 September
intervention district control district

+++
p: Generalized estimating equations
Chart 3.12 Effectiveness of education on quality of life symptoms domain
score
Chart 3.12 shows that the increase in quality of life symptoms domain

score over time in the intervention district was faster than in the control
district, the difference was significant with p<0.05

137
140
143
146
149
152
155
158
161
t0 September t1December t2 May t3 September
intervention district control district

+++
p Generalized estimating equations
Chart 3.13 Effectiveness of education on total quality of life score
Chart 3.13 shows that there was no significant difference of total quality of
life score over time between two districts (p>0.05)

symptom quality of life score
Lần
P=0.04
+++
Times
P=0.14
+++
Total quality of life score
Lần

Times

Chapter 4 - DISCUSSION
4.2 Epidemiological characteristics of asthma
The result of study revealed that the proportion of children with
diagnosed asthma in Thanh Xuan was 4.3% and in Long Bien was 3.5%,
we did not find differences of the proportion of diagnosed asthma between
two districts (p>0.05). However, the proportion of diagnosed asthma in
males was significantly higher than in females (p<0.05). Compairing with
result from the ISAAC survey between 1994-1995 among 13-14-year-old
children (the proportion of diagnosed asthma ranged from 1.6% to 28.2%)
the figure finding out from my study was at low level.
According to our survey 8.0% children in Thanh Xuan had current
wheezing, this was significant lower than in Long Bien (10.3%) (p<0.05)
whereas there was similarity in proportion of severe wheezing in two
districts (respectively 3.8% and 3.9%).
In our study, the proportion of children with diagnosed athma was
lower than those with current wheezing. When reviewing the studies in the
world, Patel has found that the proportion of children had current wheezing
from the ISAAC epidemiological surveys was higher than the proportion
of those with diagnosed asthma.
Some factors influence the proportion of asthma and wheezing in
different areas in the world such as environmental factors, host factors. In
addition, many epidemiological expects thought that study methodology,
case study defination, questionnaires using in the study and the warning in
communities have caused the differences on the results.
We selected two districts to conduct the study purposively
depending on the differences in environmetal factors (geography and level
of urbanization). The results of analysis some environmental factors in our
survey showed that there was no difference on indoor factors between two

districts but the children in two districts were believed that their outdoor

environment has been influenced of smoke, dust and chemical odour. This
could be a reason caused similarity in proportions of children with
diagnosed asthma between two districts in this study.
In our study, the asthma children stated that climate changes were
the most common trigger factor in the last 12 months. They thought that
their asthma disease became worse in the Winter.
4.3 Effectiveness of educational intervention: 12 months after enrollment
in September 2013 seven children transfered to another schools, therefore
we had no information about these children at the end of follow-up period.
4.3.1 Characteristics of asthma children at baseline
At baseline we have found out the similarities in charateritics of
asthma status, absence from school among asthma children between two
districts. The baseline asthma knowledge of the children was low and no
difference between two districts. Quality of life of the children was
impaired and two districts had similar impairment of quality of life.
4.3.2 Effectiveness on asthma status
- We observed that the percentage of children having day-time symptoms in
the intervention district decreased from 25.6% at baseline to 21.5% at the
end of a 12-month-period. In the control district the alteration of percentage
of children having day-time symptoms after one year proved that the
appearance of day-time symptoms were concerned climate factor, in
months of the Winter the percentage of children having day-time symptoms
reached a pick (September and December).
During one year we found that education could reduce the
percentage of children having night-time symptoms in the intervention
district compared with the control district (p<0.05).
The asthma control test score in the intervention group became
higher during the year and the increase was significant compared with the

control group (p<0.05). In the intervention district the percentage of

children with well-controlled asthma was improved and the improvement
was greater than the control district over time.
Therefore our results demonstrated that school-based education
program improved asthma status (decreased percentage of children having
asthma symptoms and increased percentage of children with well-
controlled asthma).
Asthma has bad impacts on studying of the schoolchildren.
Compared with the control district, in the intervention district the
percentage of children being absent from school declined significantly from
11.3% at baseline to 2.3% at completion of study (p<0.05). Thus,
educational method used in this study could reduced the percentage of
children being absent from school. This results was consistant with Levy's
finding: children in the intervention group had fewer days off school than
those in the control group.
4.3.2 Effectiveness on asthma knowledge: After one year, there was
significant improvement in knowledge score over time in the intervention
district compred with the control district (p<0.05). But the chart 3.10
demonstrates that knowledge was an instant outcome of the educational
intervention, the educated children had higher level knowledge compared
with noneducated children, however at completion of the study (at t
2
and t
3
)
the knowledge score of children in the intervention district remained stable,
this proved the requisite of maitaining education.
4.3.3 Effectiveness on quality of life: we found that the improvement in
quality of life' score in term of symptoms in the intervention district was

significant compared with the control district (p<0.05). Nevertheless, no
differences during follow-up between the intervention and the control
districts in either the total quality of life score or in term of activity
limitation and emotional function (p>0.05).

The our results showed that the school-based education program
used in this study improved quality of life symptoms score but not quality
of life activities limitation, emotion functions and total score.
According to Coffman, most studies proved that education
improved knowledge of children, meanwhile the effects of education on
asthma symptoms, school absences and quality of life were mixed.
Therefore further investigations are needed to assess the impacts of
educational intervention on outcomes of asthma particularly in symptoms
and quality of life.
This is the first study in Viet Nam on this field thus we have no
chance to compare forms and styles of school-based education programs
with other researchers in our country. According to Wheeler, choosing
appropriate members is an essential factor for successful of the school
asthma management program. We discovered that, the headmasters of
schools are persons who can staff the appropriate members for team.
Limitations: Our study has had several limitations.
Firstly, the study surveyed asthma epidemiology among
schoolchildren therefore we could missed out the children who did not
study at schools. We chose two districts purposively therefore
generalization the results of the study was limited.
Secondly, we did not enrolled parents into school asthma education
team therefore, this could impact on results of educational intervention
particularly on quality of life.
The next limitation of the study is the length of intervention period.
4 interventional sessons in 4 months and follow-up 12 months was not long

enough particularly uncontrolled asthma children.
Nevertheless, this was the first time the educational intervention
study for asthma chidren by nurses and teachers of schools was conducted
in Viet Nam. Despite these limitations, we thought that, this study was the

premise that future intervention studies in our country should be conducted
to demonstrate the roles of education on asthma management and
prevention.
CONCLUSIONS
Upon the research “Epidemiological characteristics of asthma in
13-14-year-old children and the effects of health education intervention in
two districts of Hanoi”, we came to the conclusions as follow:
5.1 Epidemiological characteristics of asthma
- Prevalence of being diagnosed asthma in 13-14-year-old children at
Thanh Xuan district was 4.3%, similar to prevalence at Long Bien 3.5%
(p>0.05). Prevalence of being diagnosed asthma in males (4.4%) was
higher than in females (3.5%) (p<0.05).
- Prevalence of current wheezing in children in Thanh Xuan district was
8.0% and lower than that in Long Bien district (10%) (p<0.05). Prevalence
of severe wheezing in children in Thanh Xuan district (3.8%) was similar to
the one in Long Bien district (3.9%) (p>0.05).
- The common risk factors of asthma attacks were climate change, cold and
fever, excercise, smoke, dust and furry animals Approximately 40% of
victims whose trigger factor of asthma was furry animals had pets at home.
5.2 Effectiveness of health education intervention
5.2.1 Effectiveness on asthma status
- At baseline there were no differences on asthma symptoms between the
two districts: at the intervention district the percentage of children having
day-time symptoms was 25.6% and night-time symptoms was 15%, at the
control group these percentages were 35.7% and 20.6% respectively

(p>0.05). Health education reduced day-time and night-time symptoms of
the asthmatic children at the intervention group after one year enrollment,
there was difference compared with the control group (p<0.05)