Background: The prevalence of obesity in children and adolescents in developing countries, especially in Asia, is increasing and becomes a significant cause of morbidity and mortality, including in Indonesia.
Objective: This study aims to analyze the intervention of physical activities on BMI, waist circumference, and body fat percentage in overweight/obese children in Asia.
Methods: This study conducted a systematic review and meta-analysis on 4,163 studies comprehensively from electronic databases, including PubMed (MEDLINE), PubMed Central (PMC), Science Direct, Springer Link, Cochrane, and hand searching. The results of data analysis were presented in narration, table, and graphics. A quantitative synthesis of the meta-analysis was conducted using the MedCalc software.
Results: Meta-analysis results showed a significant decrease in body fat percentage after the intervention of physical activities (-1.422, 95% CI, -1.697 to -1.146) with p < 0.001. The decrease of BMI z-score after the intervention of physical activities in the meta-analysis showed a significant result (-0.877, 95% CI, -1.170 to -0.585) with p < 0.001. There was a significant decrease in waist circumference in overweight/obese children and adolescents (1.111, 95% CI, -1.385 to -0.837) with p < 0.001).
Conclusion: There is a significant difference in body fat percentage, BMI z-score, and waist circumference between overweight and obese children and adolescents who received the intervention of physical activities and the control group in Asia.
Keywords: Physical activity, obesity, Asia, Systematic
review, Meta-analysis
INTRODUCTION
Obesity is caused by an excess
of energy intake compared to the body's needs, which lead to excessive energy
accumulation formed by adipose tissues. The prevalence of overweight and
obesity in children and adolescents has been increasing within the last decades,
with an estimate of 170 million children under 18 years old are overweight or
obese in 2008, which is projected to increase by 30% by 2030. The World Health
Organization (WHO) estimated a faster increase in overweight and obesity
prevalence in developing countries compared to developed countries. A study by
Jayawerdana in 2013 reported that the prevalence of obesity in children and
adolescents in Asia is the highest in developing countries. Obesity in
childhood has a 75% risk in obesity in adulthood.1,2
Obesity is related to several
metabolism disturbances, including insulin resistance and diabetes mellitus.
Although the cause of insulin resistance is multifactorial, obesity has a
strong correlation with insulin resistance. Obesity can be measured by anthropometric
measurements, such as body weight, body mass index, and waist circumference.
Currently, much literature uses body fat percentages to measure the obesity
index. For adolescents and young adults, obesity is a concerning problem
because it can reduce self-esteem and cause psychological disorders, which have
been widely investigated in Europe.2,3 To date, there have not been
many studies that provided intervention in the form of physical activities,
especially in overweight/obese adolescents in Asia.
METHODS
This study used a systematic
review and meta-analysis design. Articles were searched using PICO; population:
children with overweight or obesity, intervention: physical activity treatment,
comparison: no physical activity treatment, outcome: decrease body fat
percentage, BMI, and waist circumference. This study was conducted in Asia from
2010 to 2020 and met the inclusion and exclusion criteria using a writing
recommendation based on (PRISMA-P) 2015.
The process of the literature
search was conducted comprehensively using an electronic database from PubMed
(MEDLINE), PubMed Central (PMC), Science Direct, Springer Link, and Cochrane
Library which discussed studies concerning physical activities on overweight
and obese children using a Boolean operator and Medical Subject Headings (MeSH)
to focus the search, connecting various information and found the required
literature in the search engine. The inclusion criteria include studies with
randomized and non-randomized subjects, a minimum of 20 subjects, an
intervention of physical activities on children or adolescents with
overweight/obesity for at least 4 weeks, and the study is published in English
and Indonesian language over a period of 10 years, and the population studied
came from Asia. The articles should be full paper with an experimental design,
subjects aged > 6 years to < 18 years during observation, and the
observation should include the country of where the study took place, method of
study, samples, and type of intervention. The results of data analysis were
presented in narration, table, and graphics. A
quantitative synthesis of the meta-analysis was conducted using the MedCalc
software. The results of processing data obtained will be displayed in the form
of a forest plot by calculating the p value, with p value < 0.05 having a
statistically significant value.
The five studies
used in this study measure primary outcomes of body mass index (BMI) and
secondary outcomes of waist circumference and body fat percentage after
physical activity intervention was given. Research conducted by Anam et al. in
2010 had a one group pre-post test study design in which 20 obese children aged
9-10 years underwent anthropometric measurements and body composition before
and after exercise intervention and dietary restrictions for 8 weeks. The
exercise intervention was performed 3 times per week, each session
approximately 45 minutes with moderate to vigorous intensity. BMI in research
subjects after the intervention can decrease significantly by ± 0.7 kg/m2
(p=0.006). However, this output is not a pure result of the exercise
intervention, but is also influenced by the daily dietary restriction
intervention using a low-cholesterol diet with a calorie target of 1700
kcal/day. Meanwhile, the indicator of body fat percentage did not decrease
significantly, although there was a decrease of around 1.2% (p=0.086).4
The study by Ahmad
et al., has a randomized controlled trial design compares the results of a
family-based REDUCE (REorganize Diet, Unnecessary Screen time, and Exercise)
intervention program to improve body fat in 67 overweight and obese children
compared with 67 children in control group with age 8-11 years. Significant
differences can be observed in the body component variables, namely BMI and
waist circumference in the exercise intervention group compared to the control
group. This study carried out an intervention at least 30 minutes of moderate
to vigorous intensity exercise for 3 and 6 months. The measurement results
after 3 months of intervention still did not show significant mean differences,
including: BMI Z-score of -0.11 (p=0.086), difference in mean waist
circumference of -2.19 (p=0.116), and body fat percentage of -0.98 (p=0.209).
Meanwhile, after 6 months of intervention, there was a significant difference
in the mean of BMI and waist circumference, namely -0.14 (p=0.045) and -3.18
(p=0.021), but the percentage of body fat still showed an insignificant result
of -0.50 (p=0.530).5
In a study
conducted by Seo et al., 70 children and adolescents (6-16 years) with
overweight or obesity were divided into two intervention groups, usual care
group and exercise group. Usual care group interventions include private
medical consultations, workbooks on goals and behavior modification, exercise
counseling, monitoring and feedback on physical activity, and nutrition
counseling. Meanwhile, the exercise group received the same intervention as the
usual care group and received an additional 3 days/week exercise program with
60 minutes each session at 60%-90% maximum heart rate. Anthropometric
measurements and body composition were carried out before and after the
intervention for 12 weeks. After the intervention lasted 12 weeks there was a
significant decrease in BMI z-score in the intervention group exercise group
from 2.32 ± 0.52 to 2.24 ± 0.56 (p = 0.03). In addition, there was also a
significant decrease in body fat percentage from 32.33 ± 6.38 to 31.64 ± 6.69
(p = 0.17). Meanwhile, in the usual care group intervention group, there was no
significant difference between the measurements before and after the
intervention, in terms of BMI z-score and body fat percentage. In both
intervention groups, there was no significant decrease in waist circumference.6
The study
conducted by Li et al., had different research objectives, where the sample
used was not only children with overweight or obesity. This study seeks to run
the CHIRPY DRAGON (Chinese Primary School Children Physical Activity and
Dietary Behavior Changes Intervention) program in the form of physical activity
interventions and nutritional support for 12 months to prevent obesity in 1,562
elementary school age children in China. The planned physical activity
intervention is in the form of activities that have been agreed upon by each
school in advance for 1 hour every day entering school and sports or physical
games involving parents at home within a period of 12 months. There was a
significant difference in the mean BMI z-score between the treatment and
control groups of -0.13 ± -0.26 to 0.00 (p=0.048). However, there was no
significant difference in the variables of waist circumference and body fat
percentage between the treatment and control groups.7
The study,
conducted by Sun et al., investigated the effect of after-school exercise with
or without dietary restriction on obesity in 93 overweight adolescents in China
(13.6±0.7 years). Physical activity in the form of aerobic exercise for one
hour every day after school, 4 times a week for 10 weeks. The aerobic protocol
is a combination of several sports such as jogging, running, jumping rope,
basketball, soccer, and badminton which has a target of 40%-60% of VO2max. The
results after 10 weeks of intervention showed a significant decrease in waist
circumference (89.9±8.4cm to 81.9±8.5cm, p=0.023) and body fat percentage
(32.6±3.9% to 30.0±4.8%, p=0.026) between the exercise groups compared control.
However, BMI in the exercise intervention group did not show a significant
difference (26.2±2.7 kg/m2 to 25.4±2.7 kg/m2, p=0.942).8 A general
description of the characteristics of the research can be seen in table 4.1.
Regarding the
validity of each article, there was no random selection of samples as treatment
subjects in Anam et al study. The random distribution list was not hidden in
the Seo et al., Li et al. All studies were double blind, the studies did not
keep the type of intervention given to research subjects and researchers
themselves. Patient observation was completed and according to the initial
planning in all studies. All study participants were taken into account in each
study, but only the research of Seo et al who still include drop out samples in
data analysis as research subjects separately from completers (samples who
complete the study to the end). All studies have controlled for confounding factors
such as diet and education about behavior change. All studies analyzed the same
groups as the original research plan. The risk assessment of research bias used
in the meta-analysis can be seen in table 2.
Based on the data
presented by each study, a meta-analysis was calculate the mean differences in
BMI mean, waist circumference, and body fat percentage between the physical
activity intervention group and control group. Only studies by Ahmad et al.,
Seo et al., and Sun et al., which has a randomized controlled trial design and
uses obese or overweight children and adolescents as a subject so that
meta-analysis can only uses these three studies.
RESULTS
This systematic review
identified 4,163 relevant studies through the search strategy from electronic
media and one article from hand searching. (Figure 1) showed the process of article selection. As much as 2,473 articles from
2,498 studies were excluded for various reasons, such as only available in the
abstract form, use the intervention of medicine, the same subjects, the design
was not as expected, and in the form of a review. The remaining 25 articles
were selected based on completeness, and 20 articles were excluded because 17
of them were studies with a population outside Asia, and 3 articles had
incomplete data. Five experimental studies met the criteria for analysis in
this review.
The five studies were
conducted in Indonesia, Malaysia, China, and Korea (Asian countries) with the
keywords of physical activity,
obesity, Asia, systematic review, meta-analysis. The primary outcome
used was body mass index (BMI), and the secondary outcomes were waist
circumference and body fat percentage after the intervention of physical
activities, which can be seen in (Table 1).4,5,6,7,8
All participants had been calculated in each study. However, only Seo et al. included drop-out samples from data analysis as a separate subject from completers (samples who finished the study to the end). All studies had controlled confounding variables, such as diet and education on behavior change. All studies analyzed the same group with the initial study plan. Assessment of bias risk in this meta-analysis can be seen in (Table 2). The difference of primary and secondary outcomes before and after the intervention was assessed from BMI, waist circumference, and body fat percentage. The characteristics of the studies were summarized based on country, method, samples, and intervention, which is presented in (Table 3).
Figure 1.
PRISMA flowchart diagram
Based on the presented data
from each article, the meta-analysis was conducted to calculate the mean
difference of BMI, waist circumference, and body mass percentage between the
physical activities intervention group and control group. Only Ahmad et al.,
Seo et al., and Sun et al. used a randomized controlled trial
design and conducted the study on obese or overweight children and adolescents.
Therefore, meta-analysis can only be performed on these three studies, which is
presented in (Table 4).
The reduction of BMI z-score after physical activities intervention in this meta-analysis showed a significant result (-0.877, 95% CI, -1.170 to -0.585) according to a previous meta-analysis by George et al. on the United States population in 2018, which found a significant IMT decrease (-0.06, 95% CI, -0.09 to -0.03) from 34 studies comprising of 1,308 participants, as seen in (Figure 2).
Figure 2.
Meta-analysis forest plot from the effect of physical activity intervention on
BMI z-score.
The meta-analysis result of waist circumference in overweight and obese children and adolescents in this study showed a significant decrease (-1.111, 95% CI, -1.385 to -0.837). This was in accordance with a previous meta-analysis by Stoner et al. in 2016 on American, Australian, European, and Asian population which showed a significant decrease of waist circumference (-0.32, 95% CI, -0.51 to -0.13), and can be seen in (Figure 3).
Figure 3.
Meta-analysis forest plot from the effect of physical activity intervention on
waist circumference.
Body fat percentage decrease was significant in this meta-analysis (-1.422, 95% CI, -1.697 to -1.146). The results were in accordance with a meta-analysis conducted by Bruno et al. in Spain in 2018, which investigated the effect of aerobic exercise and physical endurance with the Mediterranean diet and showed an improvement of body composition in obese children and adolescents, including a significant decrease of body fat percentage (-1.8, 95% CI, -3.3 to -0.3), can be seen in (Figure 4).
Figure 4.
Meta-analysis forest plot from the effect of physical activity intervention on
body fat percentage.
Effect sizes analyzed in this meta-analysis include BMI, waist circumference, and body fat percentage, but because the research used is very heterogeneous, it allows for research bias. The overall results support that physical activity or exercise can improve obesity or overweight conditions in children and adolescents seen from the decrease in BMI z-score, waist circumference, and body fat percentage with statistically significant values. Heterogeneity in this study seen from the value of I2. Heterogeneity in body fat percentage has the lowest I2 value, namely 14.31% compared to I2 in BMI and waist circumference with results of 83.4% and 82.5%, respectively.