The prevalence and some associated factors of silicosis among employees working in one factory in thai nguyen province, 2020

MINISTR Y OF EDƯC ATIOJf A ND TR AlNI NG

NONBTR V OF HEAL TH

HANOI MEDIC AL UNIVERSITY

DUONG TRUNG Di e

DIETARY INTAKE AND PHYSICAL ACTIVITY

OF ELEMENTARY SCHOOL CHILDREN
TN’ HA NAM AND DIEN BIEN PROVINCES IN 2020

Major

: Doctor of Preventive Medicine

Major code

: D720302

THESIS OF GRADUATION MEDIC AL DOCTOR

COURSE 2015 - 2021

Supervisor

1. Assoc. Prof. PhD. Tran ThuyNga

2. Assoc. Prof PhD. Pham Van Phu

HANOI-2021

«s> ■>


ACKNOWLEDGEMENTS

Six years studying m Doctor of Preventive Medicine Program of Hanoi Med­
ical University (HMU) was an unforgettable experience in mv life Nutrition is a
challenging field, and it presented many difficulties to me when 1 decided to do my

thesis os it But. as a result OỈ*it. I did not only gain more knowledge, but also more
skills The implementation would not be possible if I did not receive the assistance

of several individuals and organisations Thus. I would like to express my sincere

gratitude to all of them even though it 18 unpossible to list them all
First and foremost I would like to express my heartfelt gratitude and appre­

ciation to Assoc. Prof. Tran ThuvNga. head of Department of Micronutrients. Na­

tional Institute of Nutrition for her invaluable guidance relentless encouragement
expert suggestions constructive criticism, and supervision, all of which were essen­

tial in completing this thesis

1 am thankful to Assoc Prof Pham Van Phu from the Department of Nutri­
tion. Institute for Preventive Medicine and Public Health for his great interest, en

couragement. supervision, and helpful advice on thesis progress

I would like to express my deepest thanks to the Managing Board. Depart­
ment of Training Hanoi Medical University' who had created a welcoming and

wonderful environment in the school for the past six years I wish to thank all the

teachers in die Department of Nutrition. Institute for Preventive Medicine and Pub­
lic Health, Hanoi Medical University for their valuable information pro'ided by
them in their respective fields I am grateful for their cooperation during the period

of my assignment

Finally I would like to thank my wonderful family and friends for their un­
wavering support during this ordeal Your unwavering love and support gave me

the strength to keep going.
Hanoi. 2021

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Duong Trung Due
DECLARATION

I declare that this thesis represents my

work and has not been submitted

for any degree in any university previously All the sources of information which
have been use in the thesis and external contribution are fully referenced and

acknowledged
Hanoi. 2021

Duong Trung Due

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TABLE OF CONTENT

IN TRODU CTION.............

CHaPTE R 1: LITERATURE RE VIEW.....................................

........................ 3

1.1. Dietary intake...................... ......
1 I 1 Definition of dietan-intake

............................ .

I 1.2. Methods of dietary intake assessment ..............

3

1.1.3. Recommended dietin’ allowances for elementary school children ........Ó

1.2. Physical activity....................... ....

1 2.1 Definition of physical activity.......................
I 2.2. Methods of assessing physical activity.......

-............

... 9
.. 10

I 2.3 Recommendations on physical activity for elemental} school children 13

1.3. Previous studies on dietary intake and physical activity of elementary school

children.

15

1 3.1 In the world

15

I 32. In Vietnam..........

17

CHAPTE R 2: RESEARCH su BJECTS AN D METH ODOLOGY
2.1 Study subjects:

19
19

2 1.1 Inclusion criteria

19

2 1.2 Exclusion criteria

19

2.2. Study time and study sites

2.3. Methodology

19
.19

19

...19

2.3.2. Sampling....

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21

2.3. Variables and indicators

2.4. Data collection

2.5 Potential errors and solutions.................................

23

23

2 5.1 Potential errors

2.52. Solutions...... .............

-............ -.................

23

2.6. Dau management and analysis........... .............. _ ......................................24
2.7. Ethical issues..... .... ........

,..........

CHaPTE R 3: RESULTS...............
3.1. Characteristics of research subjects ........................
3.2. Dietan- intake of research subjects...... ..............................
3.3. Physical activity of research subjects . .................
CHAPTER 4 DISCUSSION

24
25

25
—.................. 26

40
48

4.1. Dietan’ intake of the research subjects

48

4 2. Physical activity of the research subjects.............

53

CONCLU SION.............................

........58

1. Dietar,- intake of the elementary- school children in Ha Nam and Dien Bien

province in 2020....... ..............

....58

2 Physical activity- of the elementary school children in Ha Nam and Dien Bien
provincem 2020....... ................... .

RECOM MEND AHO NS
REFERE NCES

APPEND1X

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LIST OF ABBREVIATIONS
Ĩ4HR

24-hours Dietary Recall

FFQ

Food Frequency Questionnaire

MATA

Moderate to Vigorous Physical Activity

MN

National Institute of Nutrition

PA

Physical Activity

RDA

Recommended Dietary Allowances

WHO

World Health Organization

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LIST OF TABLES

Table 3 1 Demographic characteristics of the students

Table 3.2 Food consumption of students by province............ —
Table 3 3 Energy and macronutrients intake by province

25

.............

..................... 26

........... ...................... 27

Table 3 4 Micronutrients intake of the students by province.................................. 28
T able 3 5 Food consumption of students by gender..... ....................

32

Table 3 6 Energy and macronutrients intake by gender........................................... 33
Table 3. 7 Micronutrients intake of students by gender ... .... ...............

Table 3 s The proportion of protein and lipid intake by province and gender

34

. 39

Table 3 9 Average of PAQ score of students by province and gender................... 40
Table 3 10 Level of physical activity of students by province ..............

40

Table 3-11 Level of physical activity of students by gender................................. 41
Table 3

12 Frequency’ of students engaging in moderate to vigorous physical

activity for at least 60 minutes each day in the last 7 days by province41

Table 3. 13 Frequency of students engaging in moderate to vigorous physical
activity for at least 60 minutes each day in the last 7 days by gender 42

Table 3 14 Activities students attending in the past 7 days by province................43
T able 3 15 Proportion of children cycling or walking to school by province

Table 3 16 Activities children doing during school break-time bv gender

44
... 44

Table 3 17 Mean time children doing sedentary activities by province................. 45

Table 3 1 s Mean time children do sedentary activities by gender

Table 3 19 Electronic device students use most often by province

................... 46

...

Table 3 20 Average evening sleeping time of students by province and gender

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46

47


LIST OF FIGURES
Figure 3 1 Proportion of energy and macronutrients meeting RD A bv province

30

Figure 3.2 Proportion of micronuuients meeting the RDA by province.... -......... 31
Figure 3 3 Proportion of energy and macr enutrients meeting the RDA by gender 36
Figure 3 4 Proportion of micronutrients meeting the RD A by gender ................ 37

Figure 3. 5 The balance of energy substances intake of students by province........ 3S
Figure 3 6 The balance of energy substances intake of students by gender

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39


DIETARY INTAKE AND PH YS1CAL ACTIVITY OF ELEMENTARY

SCHOOL CHI LDRF.N IN ILl NAM AND DIEN BIEN PROVINCES IN 2020

ABSTRACT
Background & objectives: Dietary intake and physical activity (PA) are not only

directly affected to children's growth, but alio indirectly affected to their cognitive
abilities and stature development This study aims to describe the dietary intake and
assess the PA of elementary school children

Methods: A cross-sectional study involved 248 students aged 7-10 years in Ha
Nam and Dien Bien provinces from October to November 2020. In which. 225 die­
tan’ intakes were collected by 24 hours dietary recall method The PAQ question­
naire was used to assess the students’ PA

Results: The mean energy consumption IS under the RDA (1367 6 2 568 I Kcal)

Total protein consumption is high (143 9% of the RDA). Lipid and carbohydrate are
not meeting the RDA Calcium, magnesium, vitamin Bl. B2. B6 folate, vitamin A
D are under the RDA

The energy-generating substance structure is balanced

(P L c=16 4 23 4 60 2) The average PAQ score is 2.9 * 0 6 points The majority of
studenrs are moderate-active (81 8*o). whereas 18.2% are low-active. Students

spend an average of 1.2 -1 8 hours on sedentary activities every day Snrdents in Ha
Nam spend more time on sedentary activities than students in Dien Bien
Conclusion: The dietary intake of elementary school children aged 7-10 years in

Ha Nam and Dien Bien did not meet the RDA for energy lipid carbohydrate and
some micronutrients However. the composition of macronuuieats reached the
RDA Majority’ of students are moderate active

Keywords: dietary intake, physical activity, elementary school children. Ha Nam,

Dien Bien.


1

INTRODUCTION

Dietary intake plays an important role in nutritional status and people’s

health. A healthy diet is considered crucial for elementary school children. It does
not only directly affect to their growth, but also indirectly aflcci to children's cogni­

tive abilities and learning results [1] Several studies around the world found that

multiple dietary inadequacies are frequent among children from developing coun­
tries (2|. 13J. hl Vietnam, a study by Tran Khanh Van et al ID 2017 conducted in
Thai Nguyen province found that the dietan- intake of elementary school students

aged 7 to 10 years did not meet the recommended dietary allowances of the Nation­
al Institute of Nutrition in terms of both energy and proporúcu of macronuưients.

the study also found the lack of micronutrients in the diet [4]. Lack or excess nutri­

ents in primary school children all leads to nutritional disorders such as malnutrition
and micronutrient deficiency Nutritional disorders are thought to be caused mostly
by an inadequate diet (5)

In addition to a healthy diet, children will benefit horn a regular schedule of

physical activity The role of physic al activity in nonnal growth and development is

obvious. Increased physical activity, especially at school age aids in optimal height
and stature development [6J. Furthermore, several studies aroiad the world have

shown that physical activity can help minimize the risk of cardiovascular disease
metabolic disease and mental disorders [7Ị, [8].
However. several studies around the world and in Vietnam have shown that

the proportion of students who meet the recommendations of physical activity is

still low. According to study conducted by Zinuno L et al. in 2017. only 39% of
primary school students in Qatar engaged in moderate to extreme physical activity

for 30 minutes or more a day, students spend an average of 58 1% of their daily
time on sedentary activities [9] In Vietnam. 2016 Do Van Dung et al conducted a
study on 619 grade 5 students in Ho chi Minh City, finding that 18% of students

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did Dứt engage in physical activity, male students axe more active than female Stu

dents, and sedentary activities are common in both genders (to)

Adequate diet and physical activity are the prerequisites for children’s
growth Economic growth also contributes to social changes, including changes in

children’s eating and exercise behaviors As a result, many countries around the
world are interested in studying children's dietary intake and physical activity It

provides a scientific basis for the government to establish interventional strategies
and other health strategies to improve children's health However, in Vietnam, stud’
ics on elementary school childrens dietary intake and physical activity arc still not
really interested For the above reasons, we conduct the research “Dietary intake

and physical activity of elementary school children in Ha Nara and Dien Bien
pros Inces in 2020“ with two following objectives:
1 To describe the dietary intake of elenarntary school children in Ha Nam and Dien
Bien provinces in 2020.
2. To assess the physical activity of elementary school children m Ha Nam and Dien

Bien provinces in 2020

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5

CHAPTE R I: LITERATI RE REVIEW

1.1. Dietary intake
1.1.1. Definition of dietary intake
Dietan intake is the amount of food consumed in one day to fulfill the body’s

energy and nutrient requirements [111

The per-subject intake was determined by the amount of meals consumed per
day. the distribution of meals at different times of the day taking into consideration

meal timing and a balanced distribution of energy ratios among meals [111
1.1.2. Methods of dietary intake assessment

Dietary assessment is an evaluation of food and nutrient intake and dietary

pattern of an individual or individuals in the household or population group over

time It is on? of the four approaches in nutrition assessment to evaluating the nutri­

tional Status of individuals comprehensively. The other three are anthropometries
biochemical parameters andclinical examination (12].

Dietary intake can be assessed by subjective report and objective observa­
tion. Subjective assessment is possible using open-ended surveys such as dietary

recalls or records or using closed-ended surveys including food frequency question­
naires Each method has inherent strengths and limitations Subjective dietary as­
sessment methods that assess an individual's intake include the 24-hour dietary' re­

call (24 HR) dietary record (DR), dietary history and FFQ Data are collected with
the help of a trained interviewer OI by self-ieport [13]

24 hours dietary recall (24HR)
The 24HR is conducted in an in-depth interview manner and typically re­

quires 20 to 30 minutes to complete a single day recall Subjects are asked to report
all foods and beverages consumed in the past 24 hours This can be done via tele­


4

phone or àce-to face interview. Trained staff must conduct the interview to prompt
for details such as cooking methods and portion si2es [2] [4]
Detailed data about food preparation methods, ingredients used in mixed

dishes and the brand name of commercial products may be required according to
the research question The amounts of each food consumed are estimated in refer­
ence to a common size container (e g., bowls, cups, and glasses), standard measur­

ing cups and spoons a three-dimensional food model Of two-dimensional aids such
as photographs One advantage of the 24HR is that a relatively minimal burden is
imposed on respondents However an inevitable limitation is that all information

depends on the respondents memory and the skills of a well trained interviewer to

minimize recall bias [11), [13]
Another limitation is that this method is mainly focused on short-term intake

but long-tenn dietary exposure is especially of interest when investigating chronic

diseases. Thus, to measure average intake, multiple 24HRs are needed. Repeated
measurement not only requires a lot of resources and time, but survey repetition can

also influence n respondents* diet. A further disadvantage is from the open-ended

format which requires significant effort during data collection entry and analysis

The research team must carefully review each questionnaire to ensure that all rec­
orded da1a is included After initial review, all foods and mixed dishes consumed

according to the detailed descriptions of the respondents should be matched and

coded with the most appropriate food listed in the food composition database

Moreover, the quantity of food consumed should be converted to its actual weights
When the reported information is changed to the corresponding food code and
weight actual intakescan be calculated (11). (13).

Dietary record
Subjects record all food and beverages consumed over three consecutive

days (two weekdays and one weekend day) The consumed items can be measured
using a scale or other household items such as measuring cups or spoons, or estiư

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5

mated using a portion-size guide Trained staff must provide detailed instructions on

hosv to rec ord intake (IS]

The main advantage of dietary record is its potential to collect accurate quan­
titative information on individual foods consumed during die registration period
Because of the quality of the dietary data the dietary record is considered to be the

gold standard of the dietary methods and is often used as 3 reference in calibration
or validation studies using other less involved and less expensive methods The

weighted dietary record provides more precise estimates of intakes for individuals
which can be related to health indices such as nutritional status measured by
• blood

analytes As foods are recorded as consumed it is less likely to omit forget food

items and moreover the description thereof is more accurate When the dietary rec­
ord uses open ended questions, abundant information can be collected and analyzed

in various aspects For example if sufficient days are recorded day-to-day variation
can be studied Also, detailed descriptions of the foods consumed, and all eating oc­

casions are provided It can be easily applied to diverse groups with a wide range of

eating habits and may be used to estimate the average intake of a certain population
since provides excellent estimates for energy, nutrients foods and food groups. Die­
tan* record is suitable in metabolic and intervention studies (131(16]
Since the diet varies greatly from day to day. the reported data can only rep­

resent the current diet, not the normal diet. However, if the procedure is repeated,
the usual intake may be calculated Those who may fill out dietary record (inter­

viewees or caregivers) must be both inspired and literate (if done on paper) which
can restrict their use in certain populations (people w ith low literacy, immigrants
with low language skills, children elderly people with difficulty writing ....) Be­

cause the DR requứe high cooperatice limits the type of population that can be ap­

plied and this could compromise the generalizability of the results to the wider
population [13J. [16]
Dietary history

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ó

To assess individual long term die tan’ intake Burke developed a dietan’ his­
tory method in 1947 (17) This method requires that subjects complete a 24HR 3-

day food diary, and checklist of foods usually consumed Highly skilled profession­
als arc required to collect information on the participant's usual diet using an indepth interview (approximately 90 minutes to complete) Thus this method is rarely
used in epidemiological studies (13). (17)

Food frequency questionnaire (FFQ)
The FFQ is an advanced form of the checklist in dietan’ hrstory method and
asks respondents how often and how much food they ate over a specific period Pre­

senting about 100 to 150 foods, this questionnaire takes 20-30 minutes to complete
and can be self-administered or collected via interview. This method enables the as­
sessment of long-term dietary intakes in a relatively simple cost-effective, and

time-efficient manner Thus, various FFQs have been widely employed as a practi­
cal instrument since the 1990s FFQs should be developed specifically for each

study group and research purposes because diet may be influenced by ethnicity, cul­

ture. an individual's preference, economic status, etc (11 ]. [13 J
I. Ỉ.3. Recommended dietary allowance* for elementary school children
The Food and Nutrition Board of the vs National Academy of Sciences de­

fines The Recommended Dietary Allowance (RDA) is the average daily dietary in­

take level that is sufficient to meet the nutrient requirements of nearly all (97 to 9S
percent) healthy individuals in a specific life stage and gender group The RDA is

intended primarily for use as a goal for daily intake by individuate [ 18)

J. J.3./. Requirements ofenergy, proteins, fat and carbohydrates
Children need energy on a daily basis for basic metabolism, physical activity,
cell development and lifespan. Food is an energy- source The three main macronu­

trients in the body are carbohydrates proteins, and lipids The kilocalorie is the unit
for measuring energy purity (Kcal) (1$]. Primary- school children aged 6 to 11 years

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7

old according to the National Institute of Nutrition need betwean 1270 and 2400

Kcal per day to meet their body's growth and development (19)
Protein has been described as the most crucial material or factor in the creation
of life Protein assists in the creation maintenance, and repair of body tissues It is
especially important for a child’s growth Meat. fish, poultry, milk, and milk prod­
ucts are all good sources of protein for children. Protein requirements depending on

age gender physiological status and medical issue Protein RDAs for elementary

school children range from 33 to 50 grams per person per day Protein can account
for 20-30% of dietary energy at this age with animal protein accounting for 50% of

that [10], [20]
Lipid is a common organic compound present in plant and animal cells. It can
be found in butter fat oil milk, meat and other foods Lipid is known to be an im­
portant component of food. It provides more than twice the amount of energy as
protein and carbohydrates (about 9 kcal

I gram of lipids). Furthermore, lipid is a

carrier of lipid-soluble nutrients including vitamin A DEX. The body's ability to
absorb lipids detemrines the biological value of fat-soluble substances According

to the RDA for Vietnamese the lipid requirement for children aged (Ho 11 years is

52-72gpei person per day. with lipids conn ibuting for 20-30% of total energy Ara­
chidonic acid, a poly - unsaturated fatty acid found in animal fat. is essential for the

rapidly developing children’s body, so the ratio between animal lipids and vegetable
lipids is recommended at 70% and 30% respectively [19] [20]

Carbohydrate which includes staple foods sugars and fiber, are the most es­

sential ingredient accounting for the majority of meal voltme. It is also the body's

maul source of energy (1 gram of carbohydrates prorides 4 kcal> The body’s
main energy supply 1$ food. Carbohydrates contribute to shaping and controlling

body movements, as well as being a source of fiber According to the RDAs for Vi­
etnamese. primary’ school children’s carbohydrate requirement ranges from 210 to

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320 grams per person per day and carbohydrate account for 55 to 65% of total ener­
gy [19). po)

J.Ỉ.3.1. Requirements of vitamins and minerals
Vitamins and minerals are considered important for the growth of children In

research all over the world calcium and vitamin D in particular have been shown
to play an important role in the bone healdi and physical development of children at
this age (21). Rickets, growth restriction, and stunting axe all symptoms of calcium

and vitamin D deficiency in children (22Ị Long-term lack of calcium and vitamin D

results in decreased peak bone mass and osteoporosis in adults and the elderly Pre­
puberty. according to some studies, is a time in the life cycle where the body has

very high calcium and vitamin D needs and reacts well to treatments so it has a rea­

sonable chance of "repairing" and effectively interfering with bone structural defi­
ciencies [23]. [23], [24]. Thus, pre-pubertv is an important period to intervene in
improving bone quality which contrbutes to the formation and maintenance of a

strong skeleton in the future and improves children!* heigh1

The mineral phosphorus (P) is the second most abundant in the human body

Phosphorus is necessary for the formation and maintenance of strong bones and
teeth, as well as the maintenance of body functions [19]. [20].

The increased physiological need for physical development in growing chil­

dren is a significant factor influencing won status. Iron and protein combine to cre­
ate hemoglobin in the bodv prevent anemia and increase blood volume quickly dur­

ing development Iron absorption depends on the existence of certain substances
that increase or interfere with iron absorption. Vitamin c animal protein and organ
ic acids in fruits and vegetables work to increase iron absorptioo Iron absorption

inhibitors arc commonly found in plant-based foods such as phytate in rice and ce­
reals. tannins in some vegetables, teas, and coffee [20].

Zinc helps the body metabolize energy, form body organs helps children eat
and develop well Zinc deficiency causes children to grow slowly, reduce their re­

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9

sis lance and easily gel infections Selenium is an antioxidant nutrient involved in
the regulation of thyroid hormone activity and the redox state of vitamin c and oth

er molecules (19]. [20]

A number of other vitamins are also essential Vitamin A is a fat-soluble vita­
min that assists in the protection of the eves the prevention of night blindness the
normal development of bones and teeth the protection of mucous membranes and

skin, and die strengthening of the body’s immunity. When children reach school
age. a lack of vitamin A may have an effect on their intellectual development Vit­

amin E is yellow in color, soluble in fat-soluble solutions stable in an acid envi­
ronment unstable in the base environment slowly oxidized so it has the main role
of antioxidant Vitamin K functions primarily as a coenzyme in the synthesis of ac­

tive proteins involved in blood coagulation. Vitamin c helps absorb and use iron,
calcium folic acid anti-allergic increase immunity, anti-oxidant [19], [20].
Vitamin Bl is ven’ important Lack of vitamin Bl leads to disorders of car
bohydrate and amino acid metabolism, causing serious consequences such as affect­
ing the functico of the nervous system, causing loss of appetite decreased appetite,

and decreased muscle tone vitamin B2 is part of the group of enzymes that break
down and utilize carbohydrates proteins and lipids It is essentia] for reproductive

growth and for eyes skin hair and nails Vitamin pp (niacin) is necessary for the
synthesis of proteins lipids and the creation of DNA andRNA Niacin is particular­

ly important for the functioning of the nervous system and it is also required for the
synthesis of sex hormones Vitamin Bl 2 helps to create red blood cells keeps the
digestive system and nervous system working well plays a main role in metabolism

(19]. U0]

1.2. Ph) steal acthlty

Lĩ.i. Dt/biỉtiơn ữfphysical activity
Physical activity is defined as "bodily movement that is produced by the con-

Uaction of skeletal muscle and that substantially increases energy expenditure' [25]

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10

This term therefore includes the full range of human movement from competitive
sport and exercise to hobbies or activities involved in daily living Conversely

physical inactiviy can be described as "a state in which bodily movement IS mini­
mal and energy expenditure approximates the resting metabolic rate" [26]

Physical activity is a complex, multi- dimensional behavior Many different
modes of activity contribute to total physical activity, these include occupational

household (e f caregiving domestic cleaning) transport (e.g walking or cycling to

work) and leisure* time activities (cf. dancing swimming) Exercise is a subcate­

gory of leisure- time physical activity and is defined as physical activity in which
planned, structured and repetitive bodily movements are performed to improve or
maintain one or more components of physical fitness” [26]. [27]

Physical activity can be classified further according to its frequency, dura­

tion and intensity The frequency and duration of an activity refer to bow frequently
and for how long it is done. The amount of energy expenditure that an activity nec­

essarily requires is referred to as intensity [26]
/.2.2. MetỉiđíH o/aaailng pJtysieai activity

Physical activity is a multifaceted behavior that can be assessed in a range of

methods For measunng energy expenditure and. more precisely, physical activity', a

variety of instruments are available including objective and self-reporting methods

Both physical activity and inactivity (sedentary behavior such as sitting or televi­
sion viewing) can be measured using these methods [26], [28]

Self-Report Questionnaires

These questionnaires are the most common method of PA assessment [29]

and rely on participants' recall ability. Questionnaires vary by what they measure

(eg mode duration or frequency of PA), how data are reported (eg

activity

scores time calories), quality of the data (eg. measures of intensity, differentiating

between habitual and merely recenr activities inclusion of leisure and non-leisure

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11

activity), and how data are obtained (e g

paper and pencil assessment computer­

ized questionnaire, interview) (30)

Their advantages include cost effectiveness ease of administration and ac­

curacy in measuring intense activity, determining discrete categories of activity lev­
el (e g , low. moderate, high), ranking individuals or groups in their PA providing

details about the PA. and showing improvement across groups ox individuals Po­
tential disadvantages are that self-report questionnaires are less robust in measuring

light or moderate activity, assessing energy expenditure and may be limited by the
dependency on written language (j.e questions) and external factors (i.e social de­
sirability complexity of the questionnaire. age and seasonal variation) Self-report

questionnaires are significantly more reliable at die group than the individual lev­

el as well as when the questionnaire is structured chronologic ally and with discrete

periods [26]. [28]. [31].
Self Report Activity Diaries Logs
Self report diaries require participants to record PA in real time which pro

vides the most detailed data and can overcome some limitations of questionnaires
(j e . less susceptible to recall errors social desirabilitv bias measurement bias) To
illustrate. Bouchard's Physical Activity Record (BAR) 1$ a widely used diary in
which participants report PA for each 15-minute interval ova three days. Activities

axe rated on a scale of 1 to 9 (1 = sedentary activity. 9 a intense manual work or

high intensity sports) to yield a total energy expenditure score however. the diary is

burdensome particularly for individuals with cognitive dysfunction In addition
questionnaires not completed in real time could be subject to memory bias as well

as participant reactivity the phenomenon of behavior chaqge due to awareness of
being observed [28] [30]
Objective methods [28]

Direct Observation

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12

In direct observation an independent observer moniicn and records Pa

This method of assessment is often used when activity is restricted to a delineated
space (e g. a classroom) It is also a popular method for >oung children as they
have difficulty recalling their PA This flexible method is valuable in gathering con­

textual information (e g preferred location time and clothing) and details of the

PA (e g.. type. personalized variations to activities). Disadvantages include high
cost of time and energy, potential reactivity. difficulty obtairuag ethical approval,

and the lack of objective measures of energy expenditure
Devices: Áccelcromeiers

In recent decades, accelerometers have gained popularity given their accura­
cy. ability to capture large amounts of data, and ease of administration particularly
in large studies. Accelerometers measure acceleration (counts) in real time and de­
lect movement in up to three orthogonal planes (anteroposterior. mediolateraL and

vertical) These counts are then translated into a metric of interest, which can be bi­

ological (e g energy expenditure) or PA p3ttems (e g stationary) Devices can be
worn in numerous places on the body, including waist, hip. and thigh.
Devices: Pcdonietcrs

Pedometers measure the number of steps taken with a horizontal spring-

suspended lever amt which is deflected when the subject's hip accelerates vertically
with a force beyond a chosen threshold Pedometers correlate strongly with uniaxial

accelerometers and directly observed duration of activities Their simplicity rela­
tively low cost and ability to pick up short durations of PA (often missed by self­

report measures) make these dev ices popular Pedometer data also tend to be corre­

lated with biological outcomes and predictors (e g age. BXfl) Pedoneters appear to

yield the most accurate data for running and moderate walking, as these behaviors
require forward vertical motion.

Devices: Heart-Rate Monitors

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He lit rate monitoring is a physiological indicator of Pa and energy expend
hire providing real-time data on the frequency, duration and intensity of PA in an
unobtrusive (eg.. they can be worn as watches or on the chest). low-effort way for

periods up to one month HR monitors capture energy expenditure during activities
not involving vertical trunk displacement that many accelerometers and pedometers

miss and arc best suited to categorize subjects' PA levels (i.c . highly active, some­

what active, sedentary) as opposed to the exact amount of PA These devices tend to

show discrepancies particularly at very high and low intensities
J.2.3. JỊtcơmnưndationĩ ơn physical activityfor elementary school children

Tor school-aged children physical activity can be undertaken as part of rec­

reation and leisure (play, games, sports or planned exercise), physical education,
transportation (wheeling walking and cycling) or household chores, in the context
of educational home and community settings Physical activity improves physical

fitness (cardiorespiratory and muscular fitness), cardiometabolic health (blood pres­
sure. dyslipidemia glucose, and insulin resistance), bone health, cognitive results
(academic success, executive function) mental health (depression symptoms re­

duced) and adiposity reduction tn children (6] (32 J
According to WHO guidelines on physical activity and sedentary behavior
(6J. It is recommended that;

-

Children and adolescents should do at least an average of 60 minutes per day

of moderate- to vigorous-intensity, mostly aerobic physical activity, across
the week.

Vigorous intensity aerobic activities. as well as those that strengthen muscle
and bone, should be incorporated at least 3 days a week

WHO also recommended about sedentary behavior which is defined as time
spent sitting or lying with low energy expenditure while awake, in the context of

educational, home and community settings and ưansportation It is recommended
that; Children and adolescents should limit the amount of time spent being seden


14

tan* particularly the amount of recreational screen time Strong recommendation

low certainty evidence [6 I
In the US. 2018 U.S Department of Health and Human Services published
2nd edition of Physical Activity Guidelines for Americans (33), including Key

Guidelines for School-Aged Children and Adolescents

*

It is important to provide young people opportunities and encouragement to

participate in phvsical activities that are appropriate for their age that are en­
joyable. and that offer variety.

-

Children and adolescents ages 6 through 17 years should do 60 minutes (1

hour) or more of moderate-to-vigor OUS physical activity daily.

• Aerobic: Most of the 60 minutes or more per day’ should be either
moderate- or vigorous-intensity aerobic physical activity and should include
vigorous-intensity physical activity on at least 3 days a week

• Muscle-strengthening As part of their 60 minutes or more of daily

physical activity, children

and

adolescents should

include muscle­

strengthening physical activity on at least 3 days a week

• Bone-Strength wing As part of their 60 minutes or more of daily

physical activity children and adolescents should include bone-strengthening
physical activity on at least Ĩ days a week 118].
In Vietnam, the physical activity recommendations for students follow WHO
guidelines Besides, children should not exercise for more than 2 hours a day; in­

stead children should be involved for 30 minutes a day at first and gradually in­

crease their time There are no conprehensjve studies or specific guidelines for Vi­

etnamese people Physical activities just stop at health education communication
activities

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1.3. Previous studies on dletan* Intake and physical activity of elementary
school children

J.1
I.

ỉn rite world

Study on Dietary intake
A Stud}' examined differences between school hour and non school-hour di­

etary intakes of school-hour diet quality among Canadian children Children report­
ed consuming, on average. 746 kcal during school hours (one-third of their daily

energy intakes). Vitamins A. D. B12. calcium, and daily products densities were at

least 20% lower during school hours compared with non school hours [34].
In Malaysia. a study of BK Poh showed that dietary intake of the children

was not compatible with the recommendations where more than one-third did not
achieve the Malaysian RNI for energy, Ca and vitamin D. The present study re­

vealed that overnutrition was more prevalent than undernuưiúoa. The presence of

high prevalence of vitamin D insufficiency and the inadequate intake of Ca and vit­
amin DaTC of concern (35]
Another study conducted in Thai urban and rural area showed that protein in­
takes of all age groups were relatively high in both the areas Intakes of Ca, Fe, Zn

and vitamin c were significantly higher in urban areas than in rural areas The prev­
alence of anemia in rural areas was twice as high as that in urban areas particularly

in infants and young children However the prevalence of Fe-deficiency anemia

was sunilar in both urban and rural areas While the prevalence of vitamin A deficiency (by serum retinol cut-off <0'7 11mold) seemed IO be very low. vitamin A in­
sufficiency (by serum retinol cut-off < I 05 pmol/1) was more prevalent (29 4-

31 7%) in both the areas. The prevalence of vitamin D insufficiency ranged be­
tween 27 7 and 45 6% among the children (361

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In Indonesia, a similar study found that he percentage of children with die­

tary* intakes of energy, protein, and Vitamins A and c below the Indonesian RDA

was high and differed across urban and rural areas and age groups (J7).

Study on PA
Several researches have been conducted around the world to assess elemen­

tary* school students' physical activity' The study conducted by Zimmo L et al., in

201" showed that only 39% of primary school students in Qatar engaged in moder­
ate to vigorous physical activity for 30 minutes or more a day Students spend on

average of 58 1 ± $.4% of school time on sedentary activities Moderate to vigorous
physical activity of boys and girls was similar in age 5 while girls age 9 were less
active (23.7 ±1.5 min dav) than bovs of the same age (42.7 = 1 8 min day), ES “

0.269. p < 0.001 Neither overweight children nor children at risk for being over­
weight showed any differences in physical activity parameters when compared to
children of normal weight Our results showed, percentage of MVPA on the first
(7.7 X 5.1%) and last (7.1 X 4.1%) days of the week was generally lower compared

to other weekdays (P < 0.001) [9j
Another research conducted by Yli-piipari s et al in over 200 children aged

6 to 8 years old in the United States and Finland found that on an average school

day. students were engaged in MV PA for 20 0 min in the US and 24.1 min in Fin­

land Students* school-dav MVPA was 9 to 16 minutes higher during physical edu­
cation (PE) days compared with non-PE days (U s 25 8 vs 16 6 min day Finland
36.3 vs 20 1 min day) Girls had less MVPA and more sedentary time compared

with boys in both samples (38J
Research by Diouf et al conducted in primary school students in Dakar -

Senegal showed that PAQ results were comparable in the 156 and 42 pupils. The 42
pupils presented a light activity measured by accelerometer while PAQ classified
the majority of them (57%; n = 24) in the moderate PA level Children spent most

of their lime (min day) in sedentary activities and light activities than in moderate

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