ORIGINAL ARTICLE 288
Obesity in Indian children: Time trends and relationship with
hypertension
MANU RAJ, K. R. SUNDARAM, MARY PAUL, A. S. DEEPA,
R. KRISHNA KUMAR
ABSTRACT
Background. Limited data are available from India
regarding
the distribution and profile of childhood obesity and
hypertension. We examined the time trends in childhood obesity
in a represen-tative sample of schoolchildren from Ernakulam
District, Kerala and determined the relationship of obesity
with blood pressure.
Methods. We used a stratified
random cluster sampling method to select the children.
Anthropometric data were collected from 24 842 students, 516
years of age, during 200304. Blood pressure and
anthropometric data were collected from 20 263 students during
200506. Overweight and obesity were defined by body mass
index for gender and
age. Gender, age and height were considered for determining
hypertension.
Results. The proportion of
overweight children increased from 4.94% of the total students
in 2003 to 6.57% in 2005 (OR: 1.36; 95% CI: 1.251.47;
p<0.0001). The increase was significant in both boys and
girls. The proportion of overweight children was significantly
higher in urban regions and in private schools, and the rising
trend was limited to private schools. Systolic or diastolic
incident hypertension was found in 17.34% of overweight
children versus 10.1% of the remaining students (OR: 1.87; 95%
CI: 1.602.17; p<0.0001).
Conclusion. Childhood obesity
showed an increasing trend
in a short period of 2 years. Hypertension was common in
overweight children. The results suggest the need for greater
public awareness and prevention programmes on childhood
obesity and hypertension.Natl Med J India 2007;20:28893
INTRODUCTION
Childhood
overweight and obesity are global problems that are
on the rise. 1
Obesity in children appears to increase the risk of subsequent
morbidity, whether or not obesity persists into adulthood.2
Outcomes related to childhood obesity include hypertension,
type 2 diabetes mellitus, dyslipidaemia, left ventricular
hypertrophy, non-alcoholic steatohepatitis, obstructive sleep
apnoea, and orthopaedic and psychosocial problems.35
According to WHO, 22 million children (under 5 years of
age)
are overweight.1
Obesity is evolving as a major nutritional problem in
developing countries, affecting a substantial number of adults
and resulting in an increased burden of chronic disease.1
In national surveys conducted in the USA from the 1960s to the
1990s, the prevalence of overweight in children increased from
5% to 11%.6
Studies on urban Indian schoolchildren from
selected regions report a high prevalence of obese and
overweight children.711
In addition, studies on Indian schoolchildren have also
demonstrated that the prevalence of hypertension in overweight
children is significantly higher than that among normal
children.1215
Till date no nationally representative data
have emerged from India, which makes it difficult to project
the prevalence of obesity and overweight among children in
India. We aimed to determine the time trends of childhood
obesity and overweight in a large population of schoolchildren
from Ernakulam, Kerala, over a period of 2 years. The
relationship of obesity with childhood hypertension was also
explored.METHODS
A contiguous area with a population of
approximately 1.37 million was selected from Ernakulam
district, in central Kerala.
In the list of schools obtained from the District Education
Office, Ernakulam, there were 377 schools with a total student
strength of 202 710 in the area. Sampling was done by the
stratified random cluster sampling method. The primary
component of the study necessitated a sample size of 25 000.
Schools were stratified into 5 groups according to the
strength of children and a representative sample of 46 schools
with a cumulative population of 25 228 children was randomly
chosen. Consent to conduct the school survey and blood
pressure measurement of the students was obtained from parents
through school authorities who arranged parent meetings in the
respective schools. Verbal assent was
taken from the children after demonstrating and explaining the
procedure.
Anthropometric data (height and weight) were collected from
24 842 students, 516 years of age, during 200304. Blood
pressure and anthropometric data were collected from 20 263
students, 516 years of age, during the period 200506.
Children with a body mass index (BMI) >85th percentile
of reference data were considered overweight and those with a
BMI >95th percentile were considered obese.3
The reference data used to identify the
cut-off points were taken from the CDC 2000 dataset for BMI.16
Blood pressure (BP) was measured using
standard methodology as recommended by The Fourth Report on
the diagnosis, evaluation and treatment of high blood pressure
in children and adolescents.17
Average systolic or diastolic BP >95th percentile for
gender, age and height was considered as hypertension.
Pre-hypertension was defined as average systolic BP or
diastolic BP that was >90th percentile but <95th percentile. Children
with BP levels >120 mmHg systolic and/or 80 mmHg
diastolic were also considered pre-hypertensive.17
Children from the representative sample
were called for screening according to their classes and were
given rest for 5 minutes. The procedures were explained
briefly and demonstrated to them. Those children who were
cooperative and relaxed underwent BP measurement. Others were
given adequate time to come to terms with the procedures. The
BP was measured using a standardized mercury sphygmomanometer
and recorded by trained paramedical personnel. BP was measured
in a sitting posture with the hands resting on the examining
table with the cubital fossa supported at the level of the
heart. Chairs of adequate height were used for various groups.
The stethoscope was placed over the brachial artery pulse,
proximal and medial to the cubital fossa and below the bottom
edge of the cuff (i.e. about 2 cm above the cubital fossa).
Cuffs having a bladder width approximately 40% of the arm
circumference midway between the olecranon and the acromion
were used. The BP measurement was done on the right arm for
consistency and comparison with standard tables. Three
readings of the BP of each child were taken, maintaining an
interval of 2 minutes between readings. The mean of 3 readings
was reported. The weight and height of each child were
recorded. Height was measured by a WHO-approved wall-mounted
height measuring scale. A calibrated and standardized
mechanical weighing scale was used to measure weight.
Statistical analysis
Statistical significance of the difference
in the mean value of different variables between the 2 groups
was tested by applying Student t test. Odds ratio and
the corresponding confidence intervals were computed by using
standard methods.18 The SPSS (version
11.0) software was used for this purpose.
RESULTS
In 2003, a total of 24 842 children (11 327
boys and 13 515 girls) and in 2005, 20 263 children (9754 boys
and 10 509 girls) were examined. The descriptive data of both
surveys are shown in Tables I and II. Overweight (including
obesity) was found in 4.94% of the total students in 2003 and
6.57% in 2005. This increase is statistically significant (OR:
1.36; 95% CI: 1.251.47; p<0.0001) and was seen in both sexes
(Table III). A comparison of mean BMI between 2003 and 2005
showed an increase across all age groups. This increasing
trend was seen in both boys and girls (Fig. 1). The prevalence
of overweight was more in the age group of 511 years when
compared with those in the age group of 1216 years in 2003
and 2005. The difference in prevalence of overweight between
the age groups was not statistically significant in 2003
(5.08% v. 4.78%, p=0.29) but was significant in 2005
(7.08% v. 5.98%, p<0.005).
Comparisons were made between overweight
percentages in government and private schools (Table IV).
Private schools had
a higher percentage of overweight children than government
schools, both in the 2003 (5.17% v. 3.83%; OR: 1.37;
95% CI: 1.151.62; p<0.0003) and 2005 datasets (7.17% v.
3.23%; OR: 2.31; 95% CI: 1.872.86; p<0.0001). An increasing
trend was apparent among private schools (OR: 1.42; 95% CI:
1.301.54; p<0.0001) and not among government schools (OR:
0.84; 95% CI: 0.651.09; p>0.05). A significantly higher
proportion of children from urban schools were obese compared
with rural schools both in 2003 and 2005. Both urban and rural
schools showed an increasing trend between 2003 and 2005
(Table V).
|
Fig 1. Body mass index (BMI) comparisons
for 2003 and 2005 among girls and boys |
Table I. Descriptive data
of school survey, 2003
Age
(years) |
Boys |
Girls |
|
n |
Height (cm) |
Weight (kg) |
BMI |
n |
Height (cm) |
Weight (kg) |
BMI |
|
5 |
430 |
109.6(6.23) |
16.8(2.86) |
13.9(1.38) |
344 |
108.4(5.33) |
16.2(2.29) |
13.7(1.50) |
|
6 |
830 |
115.2(5.59) |
18.8(3.27) |
14.1(1.68) |
738
|
114.5(6.04) |
18.7(3.53)
|
14.2(1.79) |
|
7
|
872 |
120.8(6.17)
|
21.1(4.11)
|
14.4(1.88)
|
699
|
119.8(6.08)
|
20.7(3.91)
|
14.3(1.81) |
|
8 |
910 |
125.8(6.19) |
23.2(4.38) |
14.6(1.84) |
698 |
125.0(6.42)
|
23.1(4.98)
|
14.7(2.12) |
|
9 |
1016 |
131.2(6.55) |
25.9(5.70) |
14.9(2.20) |
1043 |
130.9(6.55) |
26.0(5.59) |
15.1(2.31) |
|
10 |
1235 |
135.5(6.75) |
28.3(6.92) |
15.3(2.98) |
1406 |
136.3(7.09) |
28.7(6.33) |
15.3(2.45) |
|
11 |
1213 |
140.4(7.52) |
31.0(7.37) |
15.6(2.67) |
1550 |
142.0(7.47) |
32.5(7.36) |
16.0(2.72) |
|
12 |
1340 |
145.7(7.86) |
34.4(8.13) |
16.1(2.74) |
1882 |
147.8(7.14) |
36.9(7.95) |
16.8(2.80) |
|
13 |
1266 |
152.8(8.74) |
39.7(9.50) |
16.8(2.93) |
2004 |
151.0(7.59) |
40.0(7.59) |
17.5(2.73) |
|
14 |
1282 |
158.6(8.58) |
44.0(9.82) |
17.3(2.88) |
1881 |
153.4(6.05) |
42.8(7.79) |
18.2(2.83) |
|
15 |
681 |
162.7(8.04) |
47.7(9.71) |
17.9(2.80) |
943 |
153.8(5.80) |
43.9(7.55) |
18.5(2.88) |
|
16 |
252 |
164.8(7.43) |
49.0(9.12) |
18.0(2.56) |
327 |
153.6(6.17) |
44.2(7.75) |
18.7(2.93) |
All values are mean
(SD) BMI body mass index
Table II. Descriptive data of school survey, 2005
Age
(years) |
Boys |
Girls |
|
n |
Height(cm) |
Weight(kg) |
BMI |
SBP |
DBP |
n |
Height(cm) |
Weight(kg) |
BMI |
SBP |
DBP |
|
5 |
198 |
111.6(5.63) |
17.8(3.19) |
14.2(1.53) |
95.2(8.15) |
61.0(8.41) |
222 |
110.0(5.52) |
17.2(2.89) |
14.2(1.57) |
94.1(9.25) |
5.92(9.20) |
|
6 |
689 |
116.1(5.61) |
19.5(3.77) |
14.4(1.85) |
96.5(8.68) |
60.9(8.93) |
563 |
114.8(5.55) |
18.9(3.36) |
14.2(1.66) |
95.9(8.44) |
61.7(7.97) |
|
7 |
729 |
122.0(5.61) |
21.9(4.71) |
14.6(2.20) |
97.7(8.22) |
62.9(8.75) |
594 |
121.6(5.73) |
21.8(4.61) |
14.6(2.20) |
97.9(8.35) |
63.3(8.32) |
|
8 |
788 |
127.4(6.26) |
24.5(5.32) |
15.0(2.26) |
99.5(9.09) |
64.3(8.68) |
667 |
126.2(6.33) |
23.8(4.99) |
14.8(2.16) |
98.8(9.36) |
63.7(8.51) |
|
9 |
912 |
132.1(6.32) |
26.8(5.76) |
15.2(2.32) |
100.5(8.56) |
66.0(8.31) |
855 |
132.3(6.58) |
26.7(5.69) |
15.1(2.32) |
101.5(9.36) |
66.5(8.38) |
|
10 |
1109 |
137.1(6.48) |
29.3(6.50) |
15.4(2.48) |
102.1(8.67) |
67.3(8.08) |
1178 |
137.6(7.08) |
29.9(7.10) |
15.7(2.62) |
104.4(9.87) |
68.5(8.17) |
|
11 |
1126 |
141.9(7.24) |
32.6(7.94) |
16.1(2.83) |
103.5(9.60) |
68.3(8.24) |
1301 |
142.8(7.33) |
33.7(8.01) |
16.3(2.77) |
107.3(10.01) |
70.0(7.85) |
|
12 |
1125 |
146.7(7.87) |
35.9(9.13) |
16.5(2.96) |
105.3(10.00) |
68.6(8.08) |
1269 |
148.6(6.68) |
38.2(8.07) |
17.2(2.83) |
109.8(10.35) |
71.7(7.62) |
|
13 |
1024 |
153.7(8.83) |
40.9(9.71) |
17.2(2.99) |
108.0(11.20) |
69.1(8.67) |
1388 |
152.1(6.24) |
41.5(7.82) |
17.9(2.84) |
112.3(10.57) |
72.6(7.80) |
|
14 |
1088 |
159.8(8.36) |
45.1(9.60) |
17.5(2.79) |
111.0(11.29) |
71.2(8.25) |
1481 |
154.2(5.99) |
44.0(8.53) |
18.5(3.08) |
113.2(10.42) |
73.3(7.85) |
|
15 |
687 |
164.2(7.71) |
49.3(10.51) |
18.2(3.05) |
113.8(10.92) |
72.8(8.46) |
813 |
155.3(6.28) |
45.8(8.39) |
19.0(2.88) |
114.4(10.47) |
74.2(7.94) |
|
16 |
279 |
165.9(7.50) |
52.4(11.42) |
18.9(3.28) |
115.1(11.44) |
73.2(8.20) |
178 |
155.2(6.58) |
46.6(8.92) |
19.3(3.28) |
114.7(10.87) |
74.5(7.10) |
BMI body mass index SBP systolic blood pressure in mmHg DBP
diastolic blood pressure in mmHg All values are mean (SD)
Table III. Percentages of overweight and obese children in
2005 and 2003
|
Dataset |
Overweight |
Obese |
| Overall |
Boys |
Girls |
Overall |
Boys |
Girls |
| 2005 (n=20 263) |
6.57 |
7.33 |
5.87 |
1.89 |
2.47 |
1.34 |
| 2003 (n=24
842) |
4.94 |
5.38 |
4.57 |
1.26 |
1.65 |
0.93 |
| Odds ratio |
1.36* |
1.39 |
1.30 |
1.51* |
1.51 |
1.45 |
| 95%
confidence interval |
1.251.47 |
1.241.56 |
1.161.46 |
1.291.76 |
1.241.84 |
1.131.85 |
| p value |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.0001 |
<0.003 |
* Odds ratio adjusted for gender and age
Table IV. Percentages and trends of overweight children in
private and government schools
| Dataset |
Private schools |
Government schools |
Odds ratio, 95% CI, p
value |
| 2005 |
7.17 |
3.23 |
2.31, 1.872.86, p<0.0001 |
| 2003 |
5.17 |
3.83 |
1.37, 1.151.62, p<0.0003 |
| Odds ratio |
1.42* |
0.84* |
|
| 95% CI |
1.301.54 |
0.651.09 |
|
| p value |
p<0.0001 |
p>0.05 |
|
|
* Odds ratio adjusted for gender and age
|
CI confidence interval |
Table V. Percentages and trends of overweight children in
urban and rural schools
| Dataset |
Urban |
Rural |
Odds ratio, 95% CI, p
value |
| 2005 |
8.66 |
3.75 |
2.43, 2.132.77, p<0.0001 |
| 2003 |
6.43 |
2.91 |
2.29, 2.002.62, p<0.0001 |
| Odds ratio |
1.38* |
1.30* |
|
| 95% CI |
1.261.52 |
1.111.53 |
|
| p value |
p<0.0001 |
p<0.005 |
|
|
* Odds ratio adjusted for gender
and age |
CI confidence interval |
hypertension was seen in 5.84% (3.20% in
boys, 8.29% in girls) of children and diastolic hypertension
in 6.61% (4.89% in boys, 8.2% in girls). Among the total
children, 10.65% (9.33% in boys, 11.89% in girls) had systolic
pre-hypertension and 14.75% (12.53% in boys, 16.8% in girls)
had diastolic pre-hypertension.
Systolic BP correlated better with weight (boys r=0.559,
girls r=0.539) and diastolic BP with height (boys r=0.399,
girls r=0.458). The correlation of BP with BMI was
lower compared with correlation of BP with weight as well as
height in both sexes. In both boys and girls, the mean
systolic BP in the overweight group was more than that in the
normal weight group. In boys, the mean diastolic BP in the
overweight group was more than that in the normal weight group
in all ages except in those who were 15 years old. In girls,
the mean diastolic BP in the overweight group was more than
that in the normal weight group in all age groups (Table VI).
The prevalence of incident hypertension in normal weight,
overweight and obese groups was 10.1%, 17.34% and 18.32%,
respectively. In the total sample, children in the age group
of 1216 years had a higher prevalence of incident
hypertension when compared with those in the age group of 511
years (13.18% v. 8.35%). The prevalence of systolic
hypertension (first instance) in normal weight, overweight and
obese groups was 5.38%, 12.31% and 14.66%, respectively. The
prevalence of diastolic hypertension (first instance) in
normal weight, overweight and obese groups was 6.45%, 8.86%
and 8.9%, respectively. The sex-wise differences in various
blood pressures among the 3 weight groups are given in Table
VII.
DISCUSSION
Although the prevalence values of childhood obesity in this
study are lower than those of other studies from similar
settings,711 the increasing trend of
overweight and obesity in our study was significant. During a
short span of 2 years the proportion of overweight children
increased significantly across all age groups and in both
sexes. This was accompanied by an increasing trend in mean BMI
values across all age groups. The increase was substantial in
private schools and not seen in government schools. Although
urban schools had a higher proportion of overweight children,
both urban and rural schools showed an upward trend in the
2-year period. This rapid increase in a short span of 2 years
assumes considerable epidemiological importance. A high BMI
correlates strongly with markers of secondary complications of
obesity including current blood pressures,1921
blood lipid and lipoprotein levels19,2224
and long term mortality.2
Evidence from several national health surveys in Asia
points to significant differences in prevalence of overweight
and obesity among countries.2529 Asian
countries such as Taiwan and China have experienced rapid
increases in prevalence of childhood obesity.30,31
Rapid economic growth has improved the nutritional,
socioeconomic and health status of many countries.32
Obesity has increased markedly with this nutritional evolution
in most Asian countries.33 A similar
nutritional transition is under way in India as well.29
In addition to the nutritional and socioeconomic transitions,
the behavioural transition of children is also possibly
contributing significantly to the rapidly rising prevalence of
obesity. Unhealthy eating habits and physical inactivity are
the major culprits.34 The sedentary
lifestyle of children and adolescents have been attributed
mainly to television viewing, computer games, internet,
over-emphasis on academic excellence, unscientific urban
planning
Table VI. Comparison of systolic blood pressure (SBP) and
diastolic blood pressure (DBP) between normal and overweight
groups
|
Age (Years) |
Groups |
Boys |
Girls |
|
SBP (mmHg) |
DBP (mmHg) |
SBP (mmHg) |
DBP (mmHg) |
|
Mean (SD) |
p value |
Mean (SD) |
p value |
Mean (SD) |
p value |
Mean (SD) |
p value |
|
5 |
NW |
95.1(8.25) |
0.295 |
60.8(8.43) |
0.065 |
93.7(9.10) |
0.004 |
58.8(9.28) |
0.001 |
| |
OW* |
97.9(5.84) |
|
65.8(6.90) |
|
101.6(9.19) |
|
65.1(4.98) |
|
|
6 |
NW |
96.1(8.55) |
0.001 |
60.5(8.88) |
0.001 |
95.8(8.37) |
0.041 |
61.5(7.94) |
0.023 |
| |
OW |
102.0(8.72) |
|
66.1(8.00) |
|
99.1(9.28) |
|
65.0(8.04) |
|
|
7 |
NW |
97.1(8.02) |
0.001 |
62.5(8.61) |
0.001 |
97.6(8.30) |
0.001 |
62.8(8.33) |
0.001 |
| |
OW |
103.8(7.86) |
|
66.6(9.26) |
|
102.3(7.86) |
|
68.7(5.90) |
|
|
8 |
NW |
99.0(9.01) |
0.001 |
63.9(8.60) |
0.001 |
98.4(9.22) |
0.001 |
63.7(8.56) |
0.512 |
| |
OW |
104.2(8.53) |
|
67.7(8.81) |
|
104.5(9.73) |
|
64.6(7.69) |
|
|
9 |
NW |
99.9(8.34) |
0.001 |
65.6(8.30) |
0.001 |
101.2(9.28) |
0.001 |
66.2(8.44) |
0.001 |
| |
OW |
107.7(7.64) |
|
69.8(7.47) |
|
107.4(8.89) |
|
70.3(6.37) |
|
|
10 |
NW |
101.6(8.62) |
0.001 |
67.0(8.10) |
0.001 |
103.9(9.73) |
0.001 |
68.3(8.09) |
0.001 |
| |
OW |
108.2(6.90) |
|
70.5(7.03) |
|
111.2(9.69) |
|
71.9(8.60) |
|
|
11 |
NW |
102.8(9.42) |
0.001 |
67.8(8.21) |
0.001 |
106.9(9.94) |
0.001 |
69.8(7.78) |
0.001 |
|
|
OW |
110.5(8.60) |
|
72.6(7.35) |
|
111.9(9.85) |
|
72.7(8.28) |
|
|
12 |
NW |
104.7(9.84) |
0.001 |
68.5(8.03) |
0.026 |
109.5(10.38) |
0.001 |
71.7(7.62) |
0.095 |
|
|
OW |
111.6(9.73) |
|
70.5(8.41) |
|
114.8(8.45) |
|
73.2(7.59) |
|
|
13 |
NW |
107.5(11.00) |
0.001 |
68.9(8.67) |
0.035 |
112.0(10.47) |
0.001 |
72.6(7.79) |
0.509 |
|
|
OW |
114.3(12.09) |
|
71.2(8.52) |
|
117.4(10.78) |
|
73.2(8.03) |
|
|
14 |
NW |
110.6(11.14) |
0.001 |
71.0(8.20) |
0.002 |
112.9(10.30) |
0.001 |
73.1(7.88) |
0.002 |
|
|
OW |
119.7(10.83) |
|
74.7(8.71) |
|
119.3(10.62) |
|
75.9(6.97) |
|
|
15 |
NW |
113.4(10.94) |
0.001 |
72.8(8.52) |
0.984 |
114.0(10.28) |
0.001 |
74.1(7.86) |
0.010 |
|
|
OW |
119.6(9.03) |
|
72.7(7.55) |
|
121.3(11.92) |
|
77.4(8.96) |
|
|
16 |
NW |
114.6(11.33) |
0.002 |
73.0(8.21) |
0.169 |
114.2(10.58) |
0.008 |
74.3(7.21) |
0.026 |
|
|
OW |
124.4(9.74) |
|
76.1(7.77) |
|
123.9(12.80) |
|
77.6(3.45) |
|
*Overweight includes obese children NW
normal weight group (children who are neither overweight nor
obese) OW overweight group
Table VII. Percentages of different forms of hypertension in
children with respect to gender and weight group
|
Group |
Normal (n=18 931) |
Overweight (n=1332) |
Obese (n=382) |
|
Boys |
Girls |
Total |
Boys |
Girls |
Total |
Boys |
Girls |
Total |
| Hypertension |
6.76 |
13.15 |
10.10 |
12.31 |
23.18 |
17.34 |
14.94 |
24.11 |
18.32 |
| Systolic
hypertension |
2.82 |
7.72 |
5.38 |
7.97 |
17.34 |
12.31 |
10.79 |
21.28 |
14.66 |
| Systolic
pre-hypertension |
8.76 |
11.62 |
10.25 |
16.50 |
16.21 |
16.37 |
18.67 |
23.40 |
20.42 |
| Diastolic
hypertension |
4.74 |
8.02 |
6.45 |
6.85 |
11.18 |
8.86 |
7.88 |
10.64 |
8.90 |
| Diastolic
pre-hypertension |
12.16 |
16.46 |
14.40 |
17.20 |
22.37 |
19.59 |
17.84 |
26.24 |
20.94 |
and ever-increasing automated transport.34
The difference in prevalence and trends
of overweight
among rural and urban schools demonstrated by the study could
be due to these influences. However, it is interesting that
there was an upward trend noticeable in rural schools as well.
Lifestyle changes are likely to have a greater impact on
children from affluent backgrounds as suggested by the
observation that the rapid rise in prevalence rates of
overweight was largely limited to private schools.
The prevalence of incident hypertension in
normal weight children in our study was 10.1%. The study
limitations did not permit us to follow up cases of incident
hypertension and find out actual values of persistent
hypertension which would have been much smaller than the
quoted figure. This phenomenon of low prevalence of
hypertension on subsequent readings has been demonstrated
previously. Sorof
et al.35
documented first instance hypertension as 19%, second instance
as 9.5% and third instance (persistent) as 4.5%.
The relationship of overweight and
hypertension was examined in detail. Hypertension was seen in
significantly higher percentages among overweight children
when compared with normal children (17.34% v. 10.1%).
This relationship has been reported by other studies as well.12,3641
Rosner et al.42
pooled data from 8 large epidemiological studies. Irrespective
of race, gender or age, the risk of elevated BP was
significantly higher for children in the upper compared with
the lower decile of BMI, with an odds ratio of systolic
hypertension ranging from 2.5 to 3.7. Freedman et al.39
reported that overweight children in the Bogalusa heart study
were 4.5 and 2.4 times as likely to have elevated systolic BP
and diastolic BP, respectively. Studies from India have also
shown similar trends.1215
Evidence from prospective studies in Asia
suggests that obesity is directly related to the incidence of
hypertension, type 2 diabetes and hypercholesterolaemia.26,43
According to WHO, chronic diseases are the major causes of
death in almost all countries including those in Asia.1
It is estimated that 70% of these deaths will occur in
developing Asian nations such as China, India, Pakistan,
Cambodia and Viet Nam.1
Cardiovascular diseases are responsible for the major share of
these deaths due to chronic diseases.1
South Asians appear to have worse cardiovascular disease risk
profiles when compared with Caucasian populations with similar
BMI levels.26,43
Small increases in BMI among them may translate into a
substantial increase in the burden of cardiovascular diseases.
For this reason the trends reported here are alarming even
though the overall proportion of obesity and overweight
children is far lower than that reported in other studies.
Childhood obesity and related hypertension
are issues related to lifestyle patterns in the population.
Even though the situation discussed is alarming, it provides
an excellent opportunity for prevention of cardiovascular
diseases by means of lifestyle interventions targeted at
childhood and adolescent populations, thereby attempting to
reduce morbidity and mortality arising from these diseases in
the future.
Limitations of the study
Our study did not include measurements of waisthip ratio
and skin-fold thickness. BP readings in 2003 also would have
been useful in understanding the trend. Application of
international reference standards of BMI and hypertension in
an Indian setting may have limitations. We measured incident
hypertension; hypertension can only be confirmed after a
minimum of 3 separate BP measurements demonstrating high BP.
As BP was measured in the field, an element of anxiety and
apprehension might have affected a subset of children in our
study. The data provided are univariate.
Conclusions
Childhood obesity showed a significantly
increasing trend in a short period of 2 years. Hypertension
was seen in high percentages in children with overweight and
obesity when compared with children who were neither
overweight nor obese. Unless effective interventions and
preventive strategies are instituted at the local and national
level, these observations suggest that the trend of increasing
cardiovascular disease in adults observed in recent decades
will accelerate even further. These trends are disturbing and
call for concerted efforts targeted at improving lifestyles of
children and adolescents.
ACKNOWLEDGEMENTS
The study was supported by a grant from the
Indian Council of Medical Research. This study was a component
of the Jai Vigyan Mission Mode Project on Rheumatic Fever and
Rheumatic Heart Disease.
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