JOURNAL OF TROPICAL PEDIATRICS, VOL. 59, NO. 3, 2013
Brief Report
Comparison on physical activity among adolescents with
different weight status in Shandong, China
by Zhang Ying-Xiu, Zhao Jin-Shan, Zhou Jing-Yang, Chu Zun-Hua, and Wu Guang-Jian
Shandong Center for Disease Control and Prevention, Shandong, China 250014
Correspondence: Zhang Ying-Xiu, Shandong Center for Disease Control and Prevention, 16992 Jingshi Road, Jinan, China
250014. Tel: 86-0531-82679413. Fax: 86-0531-82679413. E-mail <[email protected]>.
Summary
The present study examined the prevalence of underweight, overweight and obesity among adolescents
and compared the attitudes and behaviors of physical activity (PA) among adolescents with different
weight status in Shandong, China. A total of 19 523 students (9784 boys and 9739 girls) aged 13–18
years participated in this study. Height and weight of all subjects were measured, body mass index of
adolescents was calculated from their height and weight, and the prevalence of overweight and obesity
were obtained according to the International Obesity Task Force cut-offs. The prevalence of underweight were also obtained by the international cut-offs. PA status was assessed by a standardized
questionnaire. The overall prevalence rates of underweight, overweight and obesity were 2.0, 13.9
and 4.7% in boys and 3.3, 8.3 and 1.2% in girls, respectively. Overweight/obese adolescents had a
poor PA status compared with underweight/normal-weight adolescents. These observations highlight the
importance of PA in the prevention of overweight and obesity in adolescents.
Key words: physical activity, underweight, overweight, obesity, adolescent, prevalence.
Introduction
The prevalence of childhood overweight and obesity
has increased globally over the past several decades
in both developed and developing countries [1, 2].
Although the causes of childhood obesity are not
fully understood, among the potential determinants
of overweight and obesity, less physical activity (PA)
and unhealthy eating habits appear to be major contributors [3, 4]. The aim of the present study was
2-fold: (i) To determine the prevalence of underweight, overweight and obesity among adolescents
aged 13–18 years old in Shandong, China. (ii) To
compare the attitudes and behaviors of PA among
adolescents with different weight status.
in September to October 2010. A total of 19 523 students (9784 boys and 9739 girls) aged 13–18 years
from 16 districts in Shandong Province participated
in this study. The sampling method was stratified
multistage sampling based on selected schools. Four
public middle schools from each of the 16 districts in
Shandong were randomly selected and invited to participate in the study. From the selected schools, two
classes in each grade were selected, and all students of
the selected classes were invited to join the study. The
age groups were divided following criteria of ‘exact
age’, so that, for example, cohort 13.5 (represented
by ‘13.5’ in the plots) designates students aged 13.0–
13.9 years.
Subjects and Methods
Measurements
All measurements were conducted by a team of
trained technicians in each of the 16 districts using
the same type of apparatus and followed the same
procedures recommended by Cameron [5]. Height
without shoes was measured using metal column
height-measuring stands to the nearest 0.1 cm.
Weight was measured using lever scales to the nearest
0.1 kg while the subjects wore their underwear only.
A standardized questionnaire was designed to assess
PA status in the last 4 weeks preceding the survey.
Study population
Data for this study were obtained from a large
cross-sectional survey of schoolchildren carried out
Acknowledgements
This study was supported by the medical and health
program of Shandong, China (2009-HZ049).
ß The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
doi:10.1093/tropej/fms074
Advance Access published on 4 January 2013
226
BRIEF REPORT
The participants were asked to indicate their attitudes to physical education, extracurricular sporting
activities and long-distance running: (i) willing to
participate; (ii) ordinary; (iii) unwilling to participate.
The participants were also asked to indicate the average number of times they were engaged in PA: (i)
>1 h/d; (ii) <1 h/d.
(p < 0.05 or 0.01). Overall, the proportion of
normal weight was significantly higher in girls than
in boys (87.2 vs. 79.4%, p < 0.01).
The attitudes and behaviors of PA among
adolescents with different weight status were shown
in Tables 2 and 3. Among the four groups
(underweight, normal weight, overweight and
obese), significant differences in PA status were
observed (p < 0.001). For instance, in normal
weight group, the proportions of students willing to
participate in physical education, extracurricular
sporting activities, long-distance running and PA
>1 h/d were 83.9, 80.5, 47.9 and 31.5% for boys
and 67.3, 73.5, 36.4 and 28.3% for girls; on the contrary, these figures were only 75.3, 71.2, 25.1 and
23.6% for boys and 47.4, 58.6, 21.6 and 19.0% for
girls in obese group. Overall, overweight/obese adolescents had a poor PA status compared with
underweight/normal weight adolescents (Figs 1 and
2), and these differences were all significant
(p < 0.001).
Definitions
Body mass index of adolescents aged 13–18 years was
calculated from their height and weight (kg/m2), and
the prevalence rates of overweight and obesity were
obtained according to the International Obesity Task
Force cut-offs [6]. The prevalence rates of underweight were also obtained by the international
cut-offs [7]. Adolescents with a body mass index
above the cut-off point for underweight and below
the cut-off point for overweight were defined as
normal weight.
Statistical analysis
All subjects were divided into four groups (underweight, normal weight, overweight and obese); comparisons of PA attitudes and behaviors frequencies
among different groups were made by chi-square
test. All analyses were performed with the statistical
package SPSS/PCþ version 11.5.
Discussion
Overweight (including obesity) and thinness are important public health problems. Although both
underweight (2.0% for boys and 3.3% for girls)
and overweight/obesity (18.6% for boys and 9.5%
for girls) were observed in this study, it is concluded
that overweight and obesity were more important
public health problems in Shandong, China. Special
attention should be paid to controlling overweight
and obesity among adolescents. The present study
indicated that the prevalence of overweight and obesity among boys was higher compared with girls,
which is similar to previous reports in China
and other countries [8–12]. Our results were also contrary to findings from the USA [13], Australian [14],
Ireland [15] and Azores Islands [16]. It may be related to the differences in cultural background,
Results
The prevalence rates of underweight, overweight and
obesity among adolescents by age categories and
gender are shown in Table 1. The overall prevalence
rates of underweight, overweight and obesity were
2.0, 13.9 and 4.7% in boys and 3.3, 8.3 and 1.2%
in girls, respectively. The prevalence rates of overweight and obesity were all significantly higher in
boys than in girls in all age categories (p < 0.01).
The prevalence of underweight was significantly
higher in girls aged 13–16 years than in boys
TABLE 1
Distribution of weight status among adolescents aged 13–18 years in Shandong, China 2010
Age
Boys
n
13.5
14.5
15.5
16.5
17.5
18.5
Total
1621
1536
1771
1607
1582
1667
9784
Underweight Normal
(%)
(%)
26
36
37
30
31
38
198
(1.6)
(2.3)
(2.1)
(1.9)
(2.0)
(2.3)
(2.0)
1194
1205
1386
1309
1299
1374
7767
Girls
Overweight Obesity
(%)
(%)
(73.7) 288
(78.5) 221
(78.3) 255
(81.5) 195
(82.1) 200
(82.4) 202
(79.4) 1361
n
Underweight Normal
(%)
(%)
(17.8) 113 (7.0) 1631 62
(14.4) 74 (4.8) 1590 76
(14.4) 93 (5.3) 1751 64
(12.1) 73 (4.5) 1551 49
(12.6) 52 (3.3) 1593 37
(12.1) 53 (3.2) 1623 37
(13.9) 458 (4.7) 9739 325
(3.8)**
(4.8)**
(3.7)**
(3.2)*
(2.3)
(2.3)
(3.3)**
1378
1332
1519
1372
1424
1468
8493
Overweight Obesity
(%)
(%)
(84.5)** 174 (10.7)** 17
(83.8)** 158 (9.9)** 24
(86.8)** 140 (8.0)** 28
(88.5)** 111 (7.2)** 19
(89.4)** 117 (7.3)** 15
(90.4)** 105 (6.5)** 13
(87.2)** 805 (8.3)** 116
(1.0)**
(1.5)**
(1.6)**
(1.2)**
(0.9)**
(0.8)**
(1.2)**
*Significant difference between boys and girls, p < 0.05.
**Significant difference between boys and girls, p < 0.01.
Journal of Tropical Pediatrics
Vol. 59, No. 3
227
BRIEF REPORT
TABLE 2
Comparison on physical activities among boys with different weight status
Targets
Underweight
(n ¼ 198)
Physical education
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Extracurricular sporting activities
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Long-distance running
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Physical activities time
1 h/d (%)
<1 h/d (%)
Chi-square test
Normal
(n ¼ 7767)
Overweight
(n ¼ 1361)
Obesity
(n ¼ 458)
166 (83.8)
27 (13.6)
5 (2.5)
6516 (83.9)
1056 (77.6)
1092 (14.1)
268 (19.7)
159 (2.0)
37 (2.7)
2
x ¼ 57.89, p < 0.001
345 (75.3)
90 (19.7)
23 (5.0)
155 (78.3)
39 (19.7)
4 (2.0)
6252 (80.5)
1036 (76.1)
1300 (16.7)
282 (20.7)
215 (2.8)
43 (3.2)
2
x ¼ 39.40, p < 0.001
326 (71.2)
106 (23.1)
26 (5.7)
84 (42.4)
82 (41.4)
32 (16.2)
3724 (47.9)
501 (36.8)
2846 (36.6)
524 (38.5)
1197 (15.4)
336 (24.7)
x2 ¼ 265.08, p < 0.001
115 (25.1)
160 (34.9)
183 (40.0)
57 (28.8)
141 (71.2)
2444 (31.5)
359 (26.4)
5323 (68.5)
1002 (73.6)
x2 ¼ 24.90, p < 0.001
108 (23.6)
350 (76.4)
TABLE 3
Comparison on physical activities among girls with different weight status
Targets
Physical education
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Extracurricular sporting activities
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Long-distance running
Willing to participate (%)
Ordinary (%)
Unwilling to participate (%)
Chi-square test
Physical activities time
1 h/d (%)
<1 h/d (%)
Chi-square test
Underweight
(n ¼ 325)
Overweight
(n ¼ 805)
Obesity
(n ¼ 116)
215 (66.2)
98 (30.2)
12 (3.7)
5719 (67.3)
473 (58.8)
2520 (29.7)
298 (37.0)
254 (3.0)
34 (4.2)
x2 ¼ 42.86, p < 0.001
55 (47.4)
56 (48.3)
5 (4.3)
241 (74.2)
76 (23.4)
8 (2.5)
6239 (73.5)
523 (65.0)
2024 (23.8)
255 (31.7)
230 (2.7)
27 (3.4)
2
x ¼ 38.93, p < 0.001
68 (58.6)
44 (37.9)
4 (3.4)
141 (43.4)
124 (38.2)
60 (18.5)
3093 (36.4)
213 (26.5)
3209 (37.8)
329 (40.9)
2191 (25.8)
263 (32.7)
2
x ¼ 65.12, p < 0.001
25 (21.6)
43 (37.1)
48 (41.4)
108 (33.2)
217 (66.8)
2402 (28.3)
189 (23.5)
6091 (71.7)
616 (76.5)
2
x ¼ 17.61, p < 0.001
22 (19.0)
94 (81.0)
socio-economical levels, living environments, nutritional habits and PA levels.
PA plays an important role in the prevention of
becoming overweight and obese in childhood and
adolescence, and reduces the health risks of the condition [17]. Evidence suggests that youngsters who
are obese are less PA than those with a healthy
body composition and spend more time in sedentary
228
Normal
(n ¼ 8493)
pursuits, such as watching television and use of other
electronic media [18, 19]. Encouraging children who
are either normal weight or overweight to increase
their levels of PA and reduce their sitting time will
help to avoid excess weight gain [20]. Our results
indicated that overweight/obese adolescents had a
poor PA status compared with underweight/normal
weight adolescents; these findings strongly suggest
Journal of Tropical Pediatrics
Vol. 59, No. 3
BRIEF REPORT
100
90
83.9
77.0
80
80.4
Underweight / normal
74.9
Overweight / obesity
70
%
60
47.8
50
40
33.9
31.4
25.7
30
20
10
0
Willing to
Willing to participate Willing to participate
long-distance
participate physical
extracurricular
running
education
sporting activities
Physical activities
time≥1h per day
FIG. 1. Physical activities for boys with different weight status.
100
90
80
70
Overweight / obesity
64.2
57.3
60
%
Underweight / normal
73.5
67.3
50
36.7
40
25.8
30
28.5
22.9
20
10
0
Willing to
Willing to participate Willing to participate
participate physical
extracurricular
long-distance
education
sporting activities
running
Physical activities
time≥1h per day
FIG. 2. Physical activities for girls with different weight status.
that lack of PA is a major contributing factor to the
rising prevalence of overweight and obesity in
adolescents.
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