Overweight, obesity and associated factors among secondary school students in a northern city of Vietnam in 2011

doi:10.4236/health.2013.51004

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Vol.5, No.1, 24-29 (2013) Health

http://dx.doi.org/10.4236/health.2013.51004

Overweight, obesity and associated factors among

secondary school students in a northern city of

Vietnam in 2011*

Huong Thi Le1#†, Nga Thi Thu Vu1#†, Doan Thi Thu Huyen1†, Nguyen Van Toan2

1Institute for Preventive medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam;

#Corresponding Author: [email protected], [email protected]

2Bac Giang Secondary School of Nursing No1, Hanoi, Vietnam; [email protected]

Received 30 August 2012; revised 30 September 2012; accepted 6 October 2013

ABSTRACT

Overweight and obesity is an emerging public

health problem among school-aged children in

Bac Giang city in the Northen part of Vietnam

recently. This study aims to identify overw eight-

obesity prevalence of se condary school childre n

in this city and it’s associated factors. The study

was a nested case control in a cross-sectional

study design in 1528 secondary students se-

lected from 4 secondary schools in 2 inner

communes and 2 suburban communes of Bac

Giang city, Vietnam. Result: Overweight preva-

lence among secondary school students in Bac

Giang was 6.7%, the prevalence of obesity was

2.0%. Overweight and obesity is more preva-

lence in male students, inner communes and

students from family have higher income and

higher food expense. Overweight and obesity

was associated with higher energy intake, more

fat consumption, having supplement meals and

bedtime-meal, increased physical activities and

increased sleep duration. Conclusion: Educa-

tion campaign targeting reducing overweight and

obesity should target both parents about dietary

adequacy and balance and children about more

physical activities.

Keyw ords: Overweight; Obesity; Secondary

Students; Vietnam

1. BACKGROUND

Overweight and obesity are defined as abnormal or

excessive fat accumulation that may impair health and

becoming a trendy public health problem worldwide

[1-6]. In Vietnam, thanks to the improvement of socio-

economic status in recent years, there has been a chang-

ing of eating habit from a cereal based diets to diets with

more meat, fish, dairy products, sugar, soft drinks, con-

fectionary and processed food. Concurrently, emerging

increase of overweight and obesity is occurring across

the country among children and adolescent, especially in

big cities. Studies in Vietnam have shown that over-

weight and obesity prevalence has been steadily upward

across the country during the past decade. In the biggest

city of Vietnam, the number of people overweight and

obesity doubled from 21.4% and 36.8% during 3 years

from 2002 to 2005. The number of obesity boys also

increased three times from 6.9% in 2002 to 22.5% in

2005 [7-14]. Studies in Vietnam and elsewhere also

found out that diets with high energy, more fat and pro-

tein, high level of sweet, confectionary, soft drinks con-

sumption with low physical activities and spen ding more

time for watching TV and playing games on computers

were associated with obesity and overweight [10,11,

15-19]. In Bac Giang city in the Northern part of Viet-

nam, as according to the City Health Department, over-

weight and obesity has been increasing in recent years.

However, full understanding of the prevalence and its

associated factors are unknown; hence, scientific-based

evidence for intervention formulation is absence. There-

fore, we conduct this study in order to:

1) Identify the prevalence of overweight and obesity

among secondary students in Bac Giang city of Vietnam

in 2011.

2) Describe associated factors of overweight and obe-

sity in secondary students in Bac Giang in 2011.

*All the authors of this article declare that there is no competing o

interest regarding the publication of this article.

†HT Le, NTT Vu and TTH Doan were responsible for all aspects o

rotocol development, study coordination, data collection, data analysis

and report writing.

2. STUDY POPULATION AND DESIGN

2.1. Study Location

Bac Giang city, located 60 kilometers far from Hanoi

H. T. Le et al. / Health 5 (2013) 24-29 25

in the north. This is the provincial city and the socio-

economic and administrative hub of Bac Giang province.

The city has over 102 thousand people; live in 7 inner

communes and 9 suburban communes. Each commune

has one primary school, one secondary school and all

children of relevant age, who have permanent living

status at this commune, are all enrolled in these schools.

2.2. Study Population

The study population is secondary students enrolled in

grade 6 to grade 9 with age ranging from 11 years old

(grade 6) to 14 years old (grade 9) and a few with older

age from total 16 secondary schools across the city.

2.3. Time of Study

From January to September of 2011.

2.4. Design

2.4.1. Study Design

This is a nested case control study in a cross sectional

study. The first phase is a cross-sectional study when all

study subjects were measured height and weight to iden-

tify the point prevalence of overweight and obesity. In

the second phase, all subjects who were identified as

overweight or obesity were paired with other none-cases

subjects in the study to explore the associated factors of

overweight and obesity.

2.4.2. Sample Size and Sampling Method

Phase 1: Multi-stage cluster was applied to recruit

study’s subjects. First, the list of 7 secondary schools in

the inner communes and the list of other 9 schools in the

suburban communes in Bac Giang city were collected

from the City’s Department of education. Next, 2 schools

in the inner communes and 2 schools in the suburban

communes were randomly selected fro m these lists. Then,

in each school, each grade is regarded as a cluster and 3

classes from each cluster were randomly selected into the

study. All students in these classes were recruited into

study and were measured their height and weight.

The calculation of sample size for this phase based on

the prevalence of overweight, obesity of 8.3% from a

recent study in an area in Vietnam that has similar socio-

economic status as compared to Bac Giang city [11],

with the level of confidence at 95%, margin of error at

0.02% and design effect is 2. Minimum sample size

needed is 1462 students; however, in fact, 1528 students

were recruited into the study.

Phase 2: All overweight, obesity students detected in

the first phase will be recruited as cases and were paired

with one control. The controls were students with the

same age, gender and study at the same schools of cases

and have normal BMI for age. Controls were selected

from study subjects. Subjects in the phase 2 will be in-

terviewed about their demographic information, eating

habit, 24 h dietary, frequency of food consumption dur-

ing the last week, physical activities and static activities.

Parents or direct caregivers of these students were inter-

viewed about their family’s socio-economic status.

2.4.3. Dat a Collection

Student’s height was measured by Microtoise height

meter with the precision of 0, 1 centimeter. The meter

was tested and placed in a stable location and adjusted to

0 value before each measument; students were asked to

take out shoes and hat and were instructed to stand

straightly in the meter. Height was recorded as meter

with one decimal digit. Weight was measured by elec-

tronic SECA weigh ter with the precision of 0, 1 k ilogr am.

The weighter was tested and placed in a stable location;

students were asked to take out all of their shoes and

coats and were instructed to straightly stand in the mid-

dle of weighter. Weight was recorded as kilogram with

one decimal digit. Demographic, eating behaviors and

other information of students were collected by a pre-

designed, piloted questionnaire via face-to-face inter-

views. Questions regarding eating habit, 24 h-dietary and

frequency of food consumption in the last week were

adapted from conventional questions which are used

widely in other studies in Vietnam. Socio-economic sta tus

of students’ family was gathered via telephone-based

interviews with their parents.

Anthrometric measurement and interviews were per-

formed by experienced interviewers from Hanoi Medical

University. Before fieldwork, all interviewers were well

trained about the standard operation procedures to meas-

ure weight, height and administer interviews.

All children and their parents were carefully explained

about the purpose of the study and orally accepted to

participated to the study befo re data collection.

2.4.4. Dat a Analysis

Obesity and overweight identification. Overweight

and obesity was determined using body mass index per

age per gender (BMI) (a measure of weight adjusted for

height, calculated as weight in kilogram divided by the

square of height in meter (kg/m2) and WHO Reference

2007 for 5 - 19 years to monitor the growth of school-age

children and adolescents [20].

Overweight:+1SDBMI per age2SD

Obesity:2SDBMI per age3SD











Nutrition need and diet’s balance asses smen t and

analysis were calculated based on the Recommended

Nutrition Need for Vietnamese, published by Vietnam

National Institute of Nutrition [21]. Converting from

H. T. Le et al. / Health 5 (2013) 24-29

food intake into energy intake was performed based on

the Vietnam table of food’ nutritious components [22].

The data then was cleaned before entering into EPI-

DATA software version 2.0. We used Stata software ver-

sion 11 to analyze the data. Descriptive statistic was per-

formed.



2 tests were done to test the differences of pro-

portions of obesity and overweight among different age

groups and gender. Logistic regression was performed to

examine the relation between overweight, obesity and

associated factors. All independent variables were first

tested with univariate analysis. All important independ-

ent variables with P < 0.2 in the univariate analysis were

put into multivariate logistic regression model. Multi-

variate logistic model was refitted, tested until the final

model with the best fit was achieved.

3. RESULT

3.1. Study’s Subjects Description

The response rate of participants in the study was

100% for both students and their parents. There were

1528 students, of whom 763 male students (49.9%) and

765 female students (51.1%) participated in the study.

There was equal gender distribution across age groups.

Students at 12 years old age-group took the highest per-

cent of the total sample size (27.6%) and 46.7% partici-

pated students were from schools situated in the inner

communes of Bac Giang.

3.2. Overweight and Obesity Prevalence

In general, the proportion of overweight and obesity

were 6.7% and 2.0% respectively. There was no signifi-

cant difference of overweight and obesity across age

groups. However, there was significant difference of over-

weight and obesity rate by gender. Both overweight and

obesity rate in male students were more than 2 times

significantly higher than the similar rates in female stu-

dents. Students in inner communes had significantly h ig he r

proportion of overweight and obesity than those live in

suburban communes (Table 1).

Overweight and obesity students had average family

income significantly higher than students with normal

weight do (799.2 ± 130.1 VND vs 688.6 ± 150.0 VND,

respectively). Moreover, families of students with over-

weight and obesity spent significantly more money for

food than families of students with normal weight do

(1740.3 ± 452.3 VND vs 1573.9 ± 489.3, respectively)

(Table 2).

Diets analysis shows that both overweight and obesity

students and students with normal weight had diets with

total energy intake and energy from glucid and protid fall

within the normal range but both groups had energy in-

take from lipid exceed the normal range (24.4$ and

23.9% vs 18% - 20%). Students with overweight and

obesity had a significantly higher total energy intake than

students with normal weight (2342.6 ± 468.8 Kcal vs

2048.6 ± 344.2 Kcal, respectively) (Table 3).

Summary of logistic analysis is presented in Ta b l e 4.

Favor to eat sweet and fried food and eating practice

such as frequent eating confectionary, sweet and sweeten

milk were not associated with overweight and obesity.

Increased total energy intake, having supplement meals,

having bedtime-meal and eating fat for more than 3 times

a week were associated with being overweight and obe-

sity. In contrast, increased time for physical activities s uc h

as riding, walking, having exercise, ect. and increased

sleeping duration were protective associated factors.

4. DISCUSSION

The prevalence of overweight, obesity among 1528

students of 4 secondary schools in Bac giang (6.7%

overweight and 2.0% obesity) was lower than the result

Table 1. Distribution of overweight, obesity by age, gender and place of residence.

Distribution Overweight % (CI) Obesity % (CI)

Total (n = 1528) 6.7 (5.5 - 8.0) 2.0 (1.3 - 2.7)

By age group

11 years old 6.9 (4.0 - 9.6) 2.5 (0.7 - 4.2)

12 years old 7.8 (5.2 - 10.4) 1.2 (0.1 - 2.2)

13 years old 6.6 (4.0 - 9.2) 1.9 (0.5 - 3.3)

14 years old 5.7 (2.7 - 7.3) 2.4 (0.9 - 3.8)

By gender

Male 9.6 (7.5 - 11.7)*** 2.8 (1.6 - 3.9)*

Female 3.9 (2.5 - 5.3) 1.2 (0.4 - 1.9)

By place of residence

Inner communes 10.1 (7.9 - 12.3)*** 3.2 (1.9 - 4.4)***

Suburban communes 3.4 (2.1 - 4.7) 0.8 (0.2 - 1.4)

Differences between proportions were tested by Fisher Exact Test. ***P < 0.001; *P < 0.05

H. T. Le et al. / Health 5 (2013) 24-29 27

Table 2. Household economic status by overweight-obesity status.

Overweight, obesity studentsNormal weight students

Household economic status SD (M ± SD) P (T test)

Per capita average monthly food expense (million VND)799.2 ± 130.1 688.6 ± 150.0 P < 0.001

Per capita everage monthly income (million VND) 1740.3 ± 452.3 1573.9 ± 489.3 P = 0.02

Table 3. Characteristic of the diets.

Overweight and Obesity studentsNormal weight students

Diet characteristic (n = 88) (n = 88) Requirements of energy intake

Total energy intake (Kcal) 2342.6 ± 468.8*** 2048.6 ± 344.2 2100 - 2500

Energy intake from protein/Total energy intake (%) 16.6 18 12 - 14

Energy intake from lipid/Total energy intake (%) 24.4 23.9 18 - 20

Energy intake from glucid/Total energy intake (%) 59 57.9 66 - 70

Pr o t e i n f r o m a ni m a l / To t a l pr o t e i n (% ) 34. 9 30 30 - 50

Lipid from plant/Total lipid (%) 31.3 35.3 30 - 50

Differences of means were performed by T test; ***P < 0.001; **P < 0.01;*P < 0.05.

Table 4. Associated factors of overweight and obesity.

Univariate logistic Final multivariate logistic

Independent variables Crude OR (95% CI)P Adjusted OR (95% CI) P

Like eating sweet 1 (0.52 - 1.94) 1.000

Like eating fat 11.15 (1.40 - 89.12) 0.023

Like eating fried food 1.05 (0.58 - 1.89) 0.880

Like drinking soft drinks 1.73 (0.95 - 3.15) 0.071

Total energy intake by 100 calories increasement 1.21 (1.11 - 1.32) 0.000 1.23 (1.1 - 1.36) 0.000

Having supplement meals 1.97 (1.50 - 5.92) 0.002 3.87 (1.51 - 9.94) 0.005

Having snacks 2.09 (1.14 - 3.81) 0.016

Having bedtime-meal 2.11 (1.10 - 4.04) 0.025 2.43 (1.02 - 5.82) 0.046

Having fat more than 3 times/week 2.96 (1.39 - 6.30) 0.005 2.61 (1.01 - 6.78) 0.048

Having fried food more than 3 times/week 0.52 (0.30 - 0.95) 0.034

Having confectionary more than 3 times/week 0.91 (0.50 - 1.65) 0.760

Having soft drinks more than 3 times/week 1.27 (0.64 - 2.48) 0.490

Having sweeten milk more than 3 times/week 0.77 (0.41 - 1.45) 0.420

Total time for physical activities with 10 minutes increasement0.94 (0.90 - 0.99) 0.009 (0.91 - 0.85 - 0.97) 0.004

Total time for inphysical activities with 10 minute increasement

(watching TV, playing games, reading books, ect.) 1.053 (1.02 - 1.09) 0.006

Total time for sleeping (in hour) 0.42 (0.30 - 0.60) 0.000 0.32 (0.21 - 0.49) 0.000

of a similar study in Hue in 2007 [11] and lower than the

rate found in other recent studies in Hanoi, Buon Ma

Thuot and Ho Chi Minh city [9,12,15,17]. This lower

prevalence in Bac Giang could be explained by higher

socio-economic development and better nutrition mode

in Hanoi, Ho Chi Minh city and in other regions of Viet-

nam.

The prevalence of overweight, obesity was higher in

male students as compared with female students. This

finding is similar to the finding of Le Thi Hai et al. in

Hanoi in 2002, Vo Thi Dieu Hien et al. in Hue in 2007

and the findings of studies elsewhere in the region [9,11,

23-25].

Our study shows higher prevalence of overweight and

obesity in the inn er communes compared to the suburb an

communes, suggesting possible differences of socio-eco-

nomic status, eating behaviors and physical activities.

Additionally, students with overweight and obesity had

families with higher per capita income and higher money

for food expense. This finding is similar to the finding of

other studies [11,25].

After controlled for other factors, higher energy intake

and more fat consumption were associated with over-

weight and obesity. Our result is similar to the result of

other studies in Vietnam and elsewhere [16-18,26]. Other

eating habit such as having supplement meals or bed-

time-meal were also found significantly associated with

overweight and obesity, suggesting that there is no need

for further supplement meal and bedtime-meal for chil-

dren participated in this study. In the multivariate logistic

model, increased time for physical activities (riding bi-

cycle, exercising and walking to schools) was also asso-

ciated with lower risk of overweight and obesity, similar

to the result of Vo Thi Dieu Hien, Duncan Scott, Hong,

H. T. Le et al. / Health 5 (2013) 24-29

T.K et al., Pitrou Isabella and Sirikulchayanonta Chutima

et al. [7,11,19,25-27]. Though it is still argued in litera-

ture about the relationship between sleep duration and

overweight and obesity, we found longer sleeping time

was associated with lower rate of overweight and obesity.

This result is similar to the result of Tran Thi Hong Loan,

Hoang Thi Minh Thu and Vo Thi Dieu Hien and studies

elsewhere outsi de Vietnam [11,17,18,23].

However, unlike findings of other studies in Vietnam

and elsewhere, frequent eating sweet, confectionary and

drinking soft drinks were not found associated with over-

weight and obesity [11,16,19], suggesting that overweigh t

and obesity in the study population in Bac Giang is more

related to dietary characteristic.

5. CONCLUSION

The prevalence of overweight, obesity among second-

dary school students in Bac Giang city of Vietnam in

2011 was 6.7% and 2.0% respectively, lower than similar

prevalence in other regions of Vietnam. The prevalence

was higher in male students and students from families

with higher income and higher food expense and associ-

ated with higher energy intake, more fat consumption,

having supplement meals and bedtime-meal, increased

time for physical activities and longer sleep duration.

Parents should be educated about dietary adequacy and

balance, limiting supplement meals and bedtime meal for

children and children should be educated about increase-

ing physical activities to reduce risk of being overweight

and obesity.

REFERENCES

[1] De Onis, M., Blössner, M. and Borghi, E. (2010) Global

prevalence and trends of overweight and obesity among

preschool children. American Journal of Clinical Nutri-

tion, 92, 1257-1264. doi:10.3945/ajcn.2010.29786

[2] Freedman, D.S. (2011) Obesity—United States, 1988-

2008. Morbidity and Mortality Weekly Report, 60, 73-77.

[3] Van den Hurk, K., Van Dommelen, P., Van Buuren, S. and

Verkerk, H.P. (2007) Prevalence of overweight and obe-

sity in the Netherlands in 2003 compared to 1980 and

1997. Archives of Disease in Childhood, 92, 992-995.

doi:10.1136/adc.2006.115402

[4] Bonvecchio, A., Safdie, M. and Monterrubio, E.A. (2009)

Overweight and obesity trends in Mexican children 2 to

18 years of age from 1988 to 2006. Salud Pública de

México, 51, 586-594.

doi:10.1590/S0036-36342009001000013

[5] Nakano, T., Sei, M. and Munakata, H. (2010) Tracking

overweight and obesity in Japanese children: A six years

longitudinal study. The Journal of Medical Investigation,

57, 114-124. doi:10.2152/jmi.57.114

https://www.jstage.jst.go.jp/article/jmi/57/1%2C2/57_1%

2C2_114/_pdf

[6] Sirikulchayanonta, C., Ratanopas, W. and Temcharoen, P.

(2011) Self discipline and obesity in Bangkok school

children. BMC Public Health, 11, 1-8.

doi:10.1186/1471-2458-11-158

http://www.biomedcentral.com/content/pdf/1471-2458-11

-158.pdf

[7] Ministry of Health (2000) National Nutrition Census in

2000. Medical Publisher, Oxford, 41-105.

[8] Nguyen, Q.D. and Nguyen, L. (2008) Obesity among

school children from 9 - 11 years old and associated

factors in Hanoi and Ho Chi Minh city. Journal of Food

and Nutrition, 1, 20-25.

[9] Le, T.H. and Nguyen, T.L. (2003) Overweight and obesity

prevalence among children from 7 to 12 years old in

Hanoi in 2002. Journal of Vietnam Medical Research, 9,

25-29.

[10] Vu, H.H. and Le, T.H. (2002) Overweight and obesity and

risk factors among primary school chidren in Dong Da

district of Hanoi. Journal of Practical Medicine, 48,

50-55.

[11] Vo, T.D.H. and Hoang, K. (2008) Overweight and obesity

among school aged children from 11 to 15 years old in

some secondary schools in Hue. Journal of Practical

Medicine, 1, 28-30.

[12] Hong, T.K., Dibley, M.J., Sibbritt, D., Binh, P.N.T., Trang,

N.H.H.D. and Hanh, T.T.M. (2007) Overweight and obe-

sity are rapidly emerging among adolescents in Ho Chi

Minh City, Vietnam, 2002-2004. International Journal of

Pediatric Obesity, 2, 194-201.

doi:10.1080/17477160701520165

[13] Tuan, N.T., Tuong, P.D. and Popkin, B.M. (2008) Body

mass index (BMI) dynamics in Vietnam. European

Journal of Clinical Nutrition, 6, 78-86.

doi:10.1038/sj.ejcn.1602675

[14] Huynh, T.T.D., Michael, J.D., Sibbritt, D.W. and Tran,

T.M.H. (2005) Trends in overweight and obesity in pre-

school children in urban areas of Ho Chi Minh City,

Vietnam, from 2002 to 2005. Public Health Nutrition, 12,

702-709.

[15] Nguyen, C.K., Cao, T.Y. and Dang, T.D. (2006) Preva-

lence of overweight and obesity among primary school

children in inner communes of Buon Ma Thuot in 2004

and associated factors. Journal of Food and Nutrition,

2006, 22-26.

[16] Ta, T.L. (2001) Nutrition status and associated factors in

children from 12 - 15 years old in two secondary schools

in Hanoi. Master of Public Health Graduation Thesis,

Hanoi Medical University, Hanoi, 27-45.

[17] Tran, T.H.L. (1998) Overweight and risk factors among

school children from 6 - 11 years old in one inner district

on Ho Chi Minh city. Master of Community Nutrition

Graduation Thesis, Hanoi Medical University, Hanoi,

24-45.

[18] Hoang, T.M.T. (2003) Overweight, obesity and associated

factors among children from 6 - 11 years old in Cau Giay

District, Hanoi. Master of Public Health Graduation

Thesis, Hanoi Medical University, Hanoi, 32-57.

[19] Duncan, S. and Duncan, E.K. (2011) Modifiable risk

H. T. Le et al. / Health 5 (2013) 24-29

factors for overweight and obesity in children and ado-

lescents from São Paulo, Brazil. BMC Public Health, 585,

1-9.

[20] World Health Organization (2007) Development of a

WHO growth reference for school-aged children and

adolescents.

http://www.who.int/growthref/growthref_who_bull/en

[21] Ministry of Health—National Nutrition Institute (2003)

Recommended nutrition need for Vietnamese people.

Medical Publisher, Oxford, 10-19.

[22] Ministry of Health—National Institute of Nutrition (2000)

Vietnam table of food’s nutritious component. Medical

Publisher, Oxford, 2000.

[23] Shi, Z., Taylor, A.W., Gill, T.K. and Martin, J. (2010)

Short sleep duration and obesity among Australian chil-

dren. BMC Public Health, 10, 1-6.

doi:10.1186/1471-2458-10-609

[24] Mak, K.-K., Ho, S.-Y. and Lo, W.-S. (2010) Health-

related physical fitness and weight status in Hong Kong

adolescents. BMC Public Health, 10, 1-5.

doi:10.1186/1471-2458-10-88

[25] Hong, T.K., Rang, N.H.H.D., Dibley, M.J., Sibbritt, D.W.,

Binh, P.N.T. and Hanh, T.T.M. (2010) Factors associated

with adolescent overweight/obesity in Ho Chi Minh city.

International Journal of Pediatric Obesity, 5, 396-403.

doi:10.3109/17477160903540735

[26] Li, Y., Zhai, F., Yang, X., Schouten, E.G., Hu, X., He, Y.,

Luan, D. and Ma, G. (2007) Determinants of childhood

overweight and obesity in China. British Journal of

Nutrition, 97, 210-215. doi:10.1017/S0007114507280559

[27] Pitrou, I. and Shojaei, T. (2010) Child overweight,

associated psychopathology, and social functioning: A

French school-based survey in 6- to 11-year-old children.

Obesity (Silver Spring), 18, 809-817.

doi:10.1038/oby.2009.278