Original Article
Body-Mass Index, Waist-Size, Waist-Hip Ratio and
Cardiovascular Risk Factors in Urban Subejcts
R Gupta*+, Priyanka Rastogi**, M Sarna*, VP Gupta***, SK Sharma****, K Kothari+
Abstract
Background and Objective : Influence of obesity as determinant of cardiovascular risk factors has not been
well studied. To determine association of obesity, measured by body-mass index (BMI), waist-size or waisthip ratio (WHR), with multiple risk factors in an urban Indian population we performed an epidemiological
study.
Methods : Randomly selected adults ≥ 20 years were studied using stratified sampling. Target sample was
1800 (men 960, women 840). 1123 subjects (response 62.4%) were evaluated and blood samples were available
in 532 men and 559 women (n=1091, response 60.6%). Measurement of anthropometric variables, blood
pressure, fasting blood glucose and lipids was performed. Atherosclerosis risk factors were determined
using current guidelines. Pearson’s correlation coefficients (r) of BMI, waist and WHR with various risk
factors were determined. BMI was categorized into five groups: <20.0 Kg/m2, 20.0-22.9, 23.0-24.9, 25.0-29.9,
and ≥ 30 Kg/m2; waist size was divided into five groups and WHR into six groups in both men and women.
Prevalence of cardiovascular risk factors, smoking, hypertension, diabetes, metabolic syndrome and
dyslipidaemias was determined in each group and trends analyzed using least-squares regression.
Results : There is a significant positive correlation of BMI, waist-size and WHR with systolic BP (r= 0.46 to
0.13), diastolic BP (0.42 to 0.16), fasting glucose (0.15 to 0.26), and LDL cholesterol (0.16 to 0.03) and negative
correlation with physical activity and HDL cholesterol (-0.22 to -0.08) in both men and women (p<0.01). With
increasing BMI, waist-size and WHR, prevalence of hypertension, diabetes, and metabolic syndrome increased
significantly (p for trend <0.05). WHR increase also correlated significantly with prevalence of high total and
LDL cholesterol and triglycerides (p <0.05).
Conclusions : There is a continuous positive relationship of all markers of obesity (body-mass index, waist
size and waist hip ratio) with major coronary risk factors- hypertension, diabetes and metabolic syndrome
while WHR also correlates with lipid abnormalities. ©
I NTRODUCTION
U
rbanisation is associated with greater prevalence
of coronary risk factors in populations of
developing countries and is considered a proximate
coronary risk factor.1 The primordial changes associated
with urbanisation of traditional agrarian populations
include decreased physical activity, increased
consumption of calorie-dense foods and psychosocial
stress. The first two factors lead to increase in weight
and confer either generalised or central obesity.
*Department of Medicine, Monilek Hospital and Research
Centre, Jawahar Nagar, Jaipur 302004. +Mahatma Gandhi
National Institute of Medical Sciences, Jaipur 302022 India.
**Departments of Home Science and ***Statistics, University
of Rajasthan, Jaipur 302004; ****SMS Medical College, Jaipur
302004.
Received : 25.6.2003; Accepted : 16.6.2007
© JAPI • VOL. 55 • SEPTEMBER 2007
Consequent to these alterations the major coronary risk
factors of hypertension, high low-density lipoprotein
(LDL) cholesterol, low high-density lipoprotein (HDL)
cholesterol and diabetes develop. In developed countries,
obesity was not mentioned as a major coronary risk factor
until recently. Large prospective studies such as
Framingham Heart Study, Nurses Health Study, Buffalo
Heart Study and Second Cancer Prevention Study
provided compelling evidence2 for inclusion of obesity
as a major modifiable cardiovascular risk factor by
American Heart Association and other organisations.3
Obesity has multiple pathophysiological effects on
cardiovascular system. 3,4 Apart from it being of
importance in development of hypertension, diabetes
and dyslipidaemia, other obesity-related factors that may
have deleterious effects on coronary atherosclerosis
include insulin resistance, obstructive sleep apnoea and
haemorheological abnormalities such as low levels of
plasminogen activator inhibitor-1 and higher blood
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621
viscosity.4 Weight gain during young adulthood may be
one of the most important determinants of
cardiovascular risk.5
In India, escalating population levels of major
coronary risk factors have contributed to the coronary
heart disease (CHD) epidemic.6 Studies and reviews
have amply demonstrated that parallel to the CHD
increase in Indian urban populations there has been an
increase in prevalence of hypertension, diabetes, high
LDL cholesterol, low HDL cholesterol and the metabolic
syndrome. 1,6,7 Correlation of body-mass index (BMI) and
other markers of obesity with these risk factors has not
been well studied. We hypothesise that the major
coronary risk factors correlate positively with
generalised obesity compared to other measures such as
waist size or waist-hip ratio (WHR). To test this
hypothesis we performed an epidemiological study in
an urban Indian population.
M ETHODS
The study was approved by the institutional ethics
committee. Detailed protocol of the study has been
reported.8 Details of major cardiovascular risk factors
such as smoking, alcohol intake, amount of physical
activity, diabetes and hypertension were inquired. The
physical examination emphasized measurement of
height, weight, waist-hip ratio (WHR) and blood
pressure. Height was measured in centimetres and
weight in kilograms using calibrated spring-balance.
Waist girth was measured at the level of umbilicus with
person breathing silently and hip measured as standing
inter-trochanteric girth according to the WHO
guidelines.9 Blood pressure (BP) was measured using
standard mercury manometer. At least two readings at 5
minutes intervals were recorded and if a high BP (≥ 140/
90) was noted a third reading was taken after 30 minutes.
The lowest of the three readings was taken as BP. Fasting
blood sample was obtained from all the individuals for
estimation of glucose, total, HDL and LDL cholesterol
and triglycerides using previously standardised
techniques.
The study was designed to investigate people at
random and to cover large and varied areas of Jaipur
with a view to include persons from all walks of urban
life. Randomly chosen wards from different regions of
the city were identified so as to cover different
socioeconomic groups. Details of the population in these
wards were available from the Voters’ Lists. We randomly
selected population proportionate sample of 300 persons
(160 males, 140 females) from each locality. The total
study sample was 1800 (960 males, 840 females) who
were invited for participation. This sample size was
considered adequate for identification of major coronary
risk factors. The formulae for calculation of the sample
size have been reported. The study was preceded by
meetings with local leaders who cooperated in
622
identifying and ensuring participation of selected
subjects.
The diagnostic criteria for risk factors have been
reported.7,8 Smokers in India consume tobacco in various
forms, therefore, users of all types of tobacco products
and present and past smokers were included in smoker
category. Physical activity was measured by asking
about both work-related and leisure-time activities.
Hypertension was diagnosed when systolic BP ≥ 140
mm Hg and/or diastolic BP ≥ 90 mm Hg or a person
was a known hypertensive. BMI (weight in Kg)/(height
in metres)2 was calculated and overweight and obesity
defined as BMI ≥ 25 kg/m 2. Truncal obesity was
diagnosed when WHR was >0.90 in men and >0.80 in
women according to second report of National
Cholesterol Education Program (ATP-2).10 Abdominal
obesity was diagnosed when waist size was more than
102 cm in men and > 88 cm in women according to the
third report of National Cholesterol Education Program
(ATP-3). 7,8 Diabetes was diagnosed when history of
diagnosis was present or fasting blood glucose was ≥
126 mg/dl. Dyslipidaemia was defined by the presence
of high total cholesterol (≥ 200 mg/dl), high LDL
cholesterol (≥ 130 mg/dl), low HDL cholesterol (men
<40 mg/dl; women <50 mg/dl) or high triglycerides (≥
150 mg/dl) according to ATP-3.11 Metabolic syndrome
was defined when any three of the five diagnostic
criteria suggested by ATP-3 (abdominal obesity, high
triglycerides ≥ 150 mg/dl, low HDL cholesterol men <40
mg/dl, women <50 mg/dl, borderline or high blood
pressure ≥ 130/85 mm Hg, and fasting glucose ≥ 110
mg/dl) were present.11
Statistical analysis
Continuous variables are reported as mean ± 1 SD.
The prevalence rates are reported as percent. Variables
have been compared using either t-test or χ2 test as
appropriate. For calculations of correlation coefficients
BMI, waist size (cm) and WHR were correlated with
continuous variables of age, systolic BP, diastolic BP,
waist, WHR, fasting glucose, cholesterol, LDL
cholesterol, HDL cholesterol and triglycerides. Smoking
was graded as 0= no tobacco users, 1= non-smoke
tobacco users, 2= smokers), physical activity was graded
as 0= no activity, 1= occupational physical activity and
2= leisure-time physical activity, and included in
correlation analysis. Regression analysis was performed
with BMI, waist and WHR as independent variables
and trend graphs were prepared using GBStat Version
7.0 statistical program (Dynamic Microsystems, Silver
Spring, MD, USA). BMI was classified into various
groups for inter-group comparison of risk factors: Group
I <20.0 kg/m2, Group II 20.0-22.9, Group III 23.0-24.9,
Group IV 25.0-29.9 and Group V ≥ 30 Kg/m2 modified
from WHO classification9 and the Second US Cancer
Prevention Study.12 The waist-size was classified into
five groups and the criteria used were different for men
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© JAPI • VOL. 55 • SEPTEMBER 2007
and women. In men these groups were <80 cm, 80-89
cm, 90-99 cm, 100-109 cm and ≥ 110 cm and in women
these were <70 cm, 70-79 cm, 80-89 cm, 90-99 cm and ≥
100 cm. WHR was grouped into six categories. Men were
classified into <0.8, 0.80-0.84, 0.85-0.89, 0.90-0.94, 0.950.99 and ≥ 1.00 and women into groups of <0.75, 0.750.79, 0.80-0.84, 0.85-0.89, 0.90-0.94 and ≥ 0.95. Prevalence
of risk factors was determined in various groups and
trends examined using least-squares regression method.7
In view of large sample size for correlation analyses p
value <0.01 was considered significant while for other
statistics p values <0.05 considered significant.
Prevalence of high total- and LDL cholesterol and
triglycerides was also seen in significant proportions.
There is a significant correlation of age with waist
and WHR in men and with BMI, waist and WHR in
women (Table 2). In men, BMI correlated significantly
with waist (r= 0.77), WHR (0.38), systolic BP (0.46),
diastolic BP (0.42) and fasting glucose (0.20) and
negatively with smoking (-0.19), physical activity (-0.41)
and HDL cholesterol (-0.18). There is a weak positive
correlation with total cholesterol and LDL cholesterol.
In women there is a significant positive correlation with
waist (r= 0.80), WHR (0.19), systolic BP (0.44), diastolic
BP (0.27), cholesterol (0.11) and LDL cholesterol (0.15)
and negative correlation with smoking (-0.13), physical
activity (-0.29) and HDL cholesterol (-0.22). Waist
circumference and WHR also correlate positively with
multiple coronary risk factors as shown in Table 2. There
is a significant increase in mean levels of systolic BP,
diastolic BP and fasting glucose with increasing BMI,
waist-size and WHR in both men and women. Any
physical activity (work-related or leisure-time) was
inversely related to BMI (r2= 0.92 men, 0.98 women),
waist-size (r2= 0.92 men, 0.90 women) as well as WHR
(r2= 0.93 men, 0.95women) (Tables 3-5).
RESULTS
1123 of 1800 eligible subjects were clinically examined.
Fasting blood samples were available in 1091 subjects
(response 60.6%). 532/960 men (55.4%) and 559/840
women (66.5%) were evaluated. The prevalence of major
coronary risk factors is shown in Table 1. There is a high
prevalence of smoking or tobacco use, physical inactivity
(either work-related or leisure time), overweight and
obesity, truncal obesity, hypertension, diabetes and the
metabolic syndrome. The most common dyslipidaemia
in both males and females is low HDL cholesterol.
Table 1 : Prevalence of coronary risk factors
Risk Factor
Physical inactivity (work-related or leisure-time)
Smoking/ tobacco use
Overweight or obesity, BMI ≥ 25 kg/m 2
Obesity, BMI ≥ 30 kg/m 2
Abdominal obesity (waist, men >102 cm, women >88 cm)
Truncal obesity (waist:hip ratio men >0.9, women >0.8)
Hypertension (BP ≥ 140/ ≥ 90 or known)
Diabetes (history or fasting glucose ≥ 126 mg/dl)
High Total cholesterol ≥ 200 mg/dl
High LDL cholesterol ≥ 130 mg/dl
Low HDL cholesterol <40 mg/dl
High Triglycerides ≥ 150 mg/dl
Metabolic syndrome
Men (n=532)
Women (n=559)
180 (33.8)
200 (37.6)
201 (37.8)
68 (12.8)
115 (21.6)
305 (57.3)
197 (37.0)
70 (13.2)
199 (37.4)
197 (37.0)
292 (54.9)
172 (32.3)
122 (22.9)
232 (41.5)
65 (11.6)
281 (50.3)
112 (20.0)
236 (42.2)
380 (68.0)
210 (37.6)
64 (11.5)
241 (43.1)
252 (45.8)
303 (55.1)
160 (28.6)
223 (39.9)
Total (n=1091)
412
265
482
180
351
685
407
134
440
449
595
332
345
(37.8)
(24.3)
(44.2)
(16.5)
(32.2)
(62.8)
(37.3)
(12.3)
(39.1)
(41.5)
(55.0)
(30.4)
(31.6)
Numbers in parentheses are percent. BP - blood pressure, BMI - body mass index, LDL - low density lipoprotein, HDL - high density
lipoprotein
Table 2 : Correlation coefficients obesity indices with coronary risk factors
Age
BMI
Waist
WHR
Systolic BP
Diastolic BP
Fasting glucose
Cholesterol
LDL cholesterol
Triglycerides
HDL cholesterol
Men (n= 532)
BMI
Waist
WHR
Women (n= 559)
BMI
Waist
WHR
0.09
—
0.77**
0.38**
0.46**
0.42**
0.20**
0.06
0.07
0.09
-0.18**
0.28**
0.77**
—
0.74**
0.38**
0.15**
0.26**
0.04
0.05
0.10*
-0.19**
0.31**
0.38**
0.74**
—
0.13*
0.16**
0.15**
0.03
0.05
0.05
-0.11*
0.24**
—
0.80**
0.19**
0.44**
0.27**
0.08
0.11*
0.15**
0.04
-0.22**
0.12*
0.19**
0.38**
—
0.13*
0.04
0.09
0.03
0.03
0.06
-0.08
0.29**
0.80**
—
0.38**
0.41**
0.22**
0.15**
0.13*
0.16*
0.08
-0.24**
BMI - body mass index, WHR - waist hip ratio, BP - blood pressure. Two-tailed significance * p<0.01, ** p<0.001
© JAPI • VOL. 55 • SEPTEMBER 2007
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623
Table 3 : Prevalence of coronary risk factors in BMI categories
≥ 30.0
r2 (p value)
Men (n=532)
106
133
37 (34.9)
41 (30.8)
26 (24.5)
18 (13.5)
70 (66.0)
105 (78.9)
43 (40.6)
69 (51.9)
14 (13.2)
27 (20.3)
16 (15.1)
54 (40.6)
44 (41.5)
56 (42.1)
45 (42.4)
53 (39.8)
68 (64.2)
80 (60.2)
40 (37.7)
56 (42.1)
68
18 (26.5)
5 (7.3)
59 (86.8)
44 (64.7)
11 (16.2)
37 (54.4)
26 (38.2)
25 (36.8)
39 (57.4)
21 (30.9)
0.94
0.92
0.96
0.98
0.66
0.77
0.33
0.10
0.46
0.39
(0.007)
(0.009)
(0.003)
(<0.001)
(0.093)
(0.052)
(0.315)
(0.604)
(0.205)
(0.262)
Women (n=559)
61
169
3 (4.9)
14 (8.3)
28 (45.9)
54 (31.9)
49 (80.3)
139 (82.2)
23 (37.7)
78 (46.2)
6 (9.8)
22 (13.0)
20 (32.8)
87 (37.5)
33 (54.1)
83 (49.1)
33 (54.1)
88 (52.1)
36 (57.0)
103 (60.9)
22 (36.1)
51 (30.2)
112
10 (8.9)
16 (14.3)
89 (79.5)
75 (67.0)
27 (24.1)
85 (75.9)
48 (42.9)
54 (48.2)
78 (69.6)
24 (21.4)
0.51
0.98
0.73
0.98
0.92
0.96
0.34
0.61
0.79
0.11
(0.176)
(<0.001)
(0.066)
(0.001)
(0.009)
(0.003)
(0.306)
(0.118)
(0.044)
(0.587)
Risk factors
<20.0
20.0-22.9
23.0-24.9
Number
Smoking/tobacco
Any physical activity
Truncal obesity WHR >0.9
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol < 40mg/dl
Triglycerides ≥ 150mg/dl
138
70 (50.7)
95 (70.4)
31 (22.5)
22 (15.9)
6 (4.3)
7 (5.1)
34 (24.6)
32 (23.2)
58 (42.0)
28 (20.3)
87
34 (39.1)
36 (41.4)
40 (46.0)
19 (21.8)
12 (13.8)
8 (9.2)
39 (44.8)
42 (48.3)
47 (45.0)
27 (31.0)
Number
Smoking/tobacco
Any physical activity
Truncal obesity WHR >0.8
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol <40mg/dl
Triglycerides ≥ 150mg/dl
121
27 (22.3)
83 (68.6)
42 (34.7)
12 (9.9)
2 (1.7)
13 (10.7)
38 (31.4)
41 (33.9)
52 (43.0)
32 (26.4)
96
11 (11.5)
51 (53.1)
61 (63.5)
22 (22.9)
7 (7.3)
18 (18.7)
39 (40.6)
36 (37.5)
34 (35.4)
31 (32.3)
25.0-29.9
Numbers in parentheses are percent. BMI - body mass index, WHR - waist-hip ratio, BP - blood pressure, LDL - low density
lipoprotein, HDL - high density lipoprotein. Trends (r2) were determined by least-squares regression method.
Table 4 : Prevalence of coronary risk factors in waist-size categories
r2 (p value)
Risk factors
Groups
Number
Smoking/tobacco
Any physical activity
Overweight/obesity
Truncal obesity WHR >0.9
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol < 40mg/dl
Triglycerides ≥ 150mg/dl
<80 cm
134
68 (50.7)
95 (70.8)
1 (0.7)
17 (12.6)
16 (11.9)
6 (4.5)
6 (4.5)
33 24.6)
34 (25.4)
70 (52.2)
29 (21.6)
80-89 cm
111
41 (36.9)
50 (45.0)
10 (9.0)
45 (40.5)
31 (27.9)
7 (6.3)
10 (9.0)
52 (46.8)
52 (46.8)
90 (81.0)
40 (36.0)
Men (n=532)
90-99 cm
133
51 (38.3)
29 (18.0)
54 (40.6)
96 (72.1)
54 (40.6)
27 (20.3)
22 (16.5)
55 (41.4)
54 (40.6)
83 (62.4)
48 (36.0)
Groups
Number
Smoking/tobacco
Any physical activity
Overweight/obesity
Truncal obesity WHR >0.8
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol <40mg/dl
Triglycerides ≥ 150mg/dl
<70 cm
83
20 (24.0)
67 (80.7)
0 (0.0)
9 (10.8)
2 (2.4)
1 (1.2)
6 (7.2)
22 (26.5)
23 (27.7)
34 (41.0)
16 (19.3)
70-79 cm
100
12 (12.0)
49 (49.0)
10 (10.0)
50 (50.0)
16 (16.0)
3 (3.0)
8 (8.0)
38 (38.0)
39 (39.0)
36 (36.0)
27 (27.0)
Women (n=559)
80-89 cm
90-99 cm
159
134
17 (10.7)
8 (5.9)
61 (38.4)
45 (33.5)
78 (49.1)
115 (85.8)
121 (76.1)
123 (91.7)
72 (45.3)
64 (47.7)
20 (12.6)
16 (11.9)
45 (28.3)
93 (69.4)
75 (47.2)
65 (48.5)
77 (48.4)
67 (50.0)
90 (56.6)
83 (61.9)
52 (32.7)
45 (33.6)
100-109 cm
88
18 (20.4)
7 (7.9)
70 (79.5)
84 (95.4)
49 (55.6)
12 (13.6)
34 (38.6)
35 (39.8)
34 (38.6)
47 (53.4)
31 (35.2)
≥ 110
66
22 (33.3)
4 (6.0)
66 (100.0)
63 (95.4)
47 (71.2)
18 (27.3)
50 (75.8)
24 (36.4)
23 (34.8)
13 (19.7)
24 (36.4)
0.56
0.90
0.97
0.93
0.99
0.77
0.86
0.10
0.04
0.43
0.50
(0.148)
(0.014)
(0.003)
(0.008)
(<0.001)
(0.051)
(0.022)
(0.603)
(0.732)
(0.227)
(0.179)
≥ 100 cm
83
8 (9.6)
10 (12.0)
78 (93.9)
77 (92.7)
56 (67.4)
24 (28.9)
71 (85.5)
41 (49.4)
46 (55.4)
60 (72.3)
20 (24.1)
0.63
0.92
0.95
0.89
0.96
0.86
0.88
0.79
0.93
0.87
0.18
(0.108)
(0.009)
(0.004)
(0.016)
(0.004)
(0.023)
(0.005)
(0.017)
(0.008)
(0.21)
(0.471)
Numbers in parentheses are percent. BMI - body mass index, WHR - waist-hip ratio, BP - blood pressure, LDL - low density
lipoprotein, HDL - high density lipoprotein. Trends (r2) were determined by least-squares regression method.
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© JAPI • VOL. 55 • SEPTEMBER 2007
Table 5: Prevalence of coronary risk factors in WHR categories
WHR Groups
<0.8
0.80-0.84
0.85-0.89
Men (n=532)
0.90-0.94
0.95-0.99
≥ 1.00
r2 (p value)
Number
Smoking/tobacco
Any physical activity
Overweight/Obesity BMI ≥ 25.0
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol < 40mg/dl
Triglycerides ≥ 150mg/dl
22
8 (36.4)
17 (77.3)
1 (4.5)
2 (9.1)
1 (4.5)
1 (4.5)
1 (4.5)
3 (13.6)
7 (31.8)
4 (18.2)
62
30 (48.4)
44 (71.0)
6 (9.7)
4 (6.4)
1 (1.6)
3 (4.8)
17 (27.4)
18 (29.0)
27 (43.5)
18 (29.0)
114
53 (46.5)
63 (55.3)
19 (16.7)
29 (25.4)
5 (4.4)
10 (8.8)
49 (43.0)
48 (42.1)
62 (54.4)
33 (28.9)
136
47 (40.4)
33 (24.3)
55 (40.4)
52 (38.2)
24 (17.6)
29 (21.3)
52 (38.2)
51 (37.5)
69 (50.7)
47 (34.6)
82
28
10
55
42
15
34
35
31
46
29
0.29
0.93
0.96
0.88
0.75
0.91
0.66
0.55
0.67
0.77
WHR Groups
Number
Smoking/tobacco
Any physical activity
Overweight/Obesity BMI ≥ 25.0
Hypertension
Diabetes
Metabolic syndrome
Cholesterol ≥ 200mg/dl
LDL cholesterol ≥ 130mg/dl
HDL cholesterol <40mg/dl
Triglycerides ≥ 150mg/dl
<0.75
44
6 (13.6)
27 (61.4)
10 (22.7)
11 (25.0)
4 (9.1)
11 (25.0)
11 (25.0)
13 (29.5)
23 (52.3)
9 (20.5)
0.75-0.79
101
13 (12.9)
60 (89.4)
32 (31.7)
25 (24.8)
3 (3.0)
18 (17.8)
41 (40.6)
40 939.6)
44 (43.6)
25 (24.7)
0.80-0.84
169
20 (11.8)
67 (39.6)
79 (36.7)
63 (37.3)
19 (11.2)
52 (30.8)
73 (43.2)
79 (46.7)
94 (55.6)
48 (28.4)
Women (n=559)
0.85-0.89
0.90-0.94
136
72
16 (11.8)
5 (6.9)
49 (36.0)
21 (29.2)
94 (69.1)
41 (56.9)
57 (41.9)
33 (45.8)
22 (13.0)
10 (13.9)
67 (49/3)
48 (66.7)
64 (47.0)
33 (45.8)
63 (46.3)
35 (48.6)
66 (48.5)
48 (66.7)
42 (30.9)
25 (34.7)
116
34 (29.3)
13 (11.2)
65 (56.0)
68 (58.6)
24 (20.7)
45 (38.8)
45 (38.8)
46 (39.7)
81 (69.8)
41 (35.3)
(34.1)
(12.2)
(67.1)
(51.2)
(18.3)
(41.5)
(42.7)
(37.8)
(56.1)
(35.4)
≥ 0.95
37
5 (13.5)
8 (21.6)
25 (67.6)
21 (66.8)
6 (16.2)
27 (73.0)
19 (51.4)
22 (59.4)
28 (75.7)
11 (29.7)
(0.273)
(0.002)
(<0.001)
(0.006)
(0.025)
(0.003)
(0.048)
(0.092)
(0.045)
(0.022)
r2 (p value)
0.25
0.95
0.83
0.95
0.66
0.90
0.77
0.89
0.64
0.75
(0.318)
(<0.001)
(0.012)
(<0.001)
(0.049)
(0.004)
(0.022)
(0.005)
(0.057)
(0.026)
Numbers in parentheses are percent. BMI body mass index, WHR waist-hip ratio, BP blood pressure, LDL low density lipoprotein,
HDL high density lipoprotein. Trends (r 2) were determined by least-squares regression method.
Fig. 1 : Increasing trends in prevalence of hypertension, diabetes and
metabolic syndrome with increasing levels of body mass index (top
panel), waist size (middle panel) and waist-hip ratio (bottom panel).
Light shaded bars= men, dark shaded bars= women. All the trends
are statistically significant (p <0.05).
Prevalence of various risk factors with increasing BMI
is shown in Table 3. Smoking shows significant inverse
© JAPI • VOL. 55 • SEPTEMBER 2007
correlation with BMI in men (r2= 0.94, p=0.007) There is
a significant increase in the prevalence of hypertension,
diabetes, and metabolic syndrome with BMI in both men
and women. BMI <20 kg/m2 was associated with the
lowest prevalence of hypertension, diabetes, and
metabolic syndrome and a progressive increase is seen
in these risk factors groups with increasing BMI (Fig. 1,
top panel). A steep increase in the prevalence of
hypertension, diabetes and metabolic syndrome is
observed at BMI ≥ 20 kg/m2.
Increasing trends are also observed with waist-size
for prevalence of hypertension, diabetes and metabolic
syndrome in both men and women (Table 4). In men the
lowest prevalence of these risk factors is seen in waist
<80 cm and in women with waist <70 cm and a steep
increase is observed at waist size >90 cm in men and
>80 cm in women (Fig. 1, middle panel).
Increase in prevalence of hypertension, diabetes and
metabolic syndrome is also observed as WHR increases
(Table 5). Lowest prevalence of these risk factors was
observed in WHR <0.80 in men and <0.75 in women
with a progressive increase with increasing WHR (Fig.
1, bottom panel). In addition there is a significant positive
correlation of WHR with prevalence of high total
cholesterol (r 2 0.66 men, 0.77 women), high LDL
cholesterol (0.55 men, 0.89 women), low HDL cholesterol
(0.67 men, 0.64 women) and high triglycerides (0.77 men,
0.75 women) (p<0.05).
www.japi.org
625
DISCUSSION
This study shows that obesity measured either as
body-mass index, waist-size or waist-hip ratio, is a major
determinant of cardiovascular risk factorshypertension, diabetes and metabolic syndrome in both
men and women in an Indian urban population. WHR
is also important determinant of hypercholesterolaemia,
low HDL and hypertriglyceridemia.
Body weight is determined by many factors, such as
genetic, behavioural, cultural, socio-economic,
psychosocial and psychological mechanisms.3,4 Many
of these factors influence health independently or
through mechanisms other than body weight. Excess
body weight is a risk factor for a variety of health hazards,
but it is also a marker of other factors that are directly or
indirectly related to health, such as physical activity,
diet, socio-economic status and smoking. The present
study shows that regular physical activity of any type
(work-related or leisure-time) is inversely related to all
measures of obesity, viz., BMI, waist and WHR. The other
major determinant of obesity is diet. We did not inquire
detailed dietary history of the subjects and this is a study
limitation.
Despite the positive association between bodyweight
and the risk of CHD in many studies the question of
whether this risk is independent of other factors is still
debated.2 Obesity is closely related to several known
cardiovascular risk factors, lipid abnormalities and
impaired glucose metabolism and it has a complicated
association with smoking.12 Obese subjects on average
have higher BP, higher serum total cholesterol, lower
HDL cholesterol, higher serum triglycerides, higher
blood glucose and a higher plasma insulin levels than
lean persons. 5 The present study also shows that
increasing obesity measured by BMI, waist or WHR is
associated with escalating prevalence of multiple
cardiovascular risk factors. The individual and
independent effect of body weight on the risk of coronary
heart disease is difficult to estimate because obesity
exerts much of its effect through the enhancement of other
risk factors.
In Framingham Study, Hubert et al13 and Garrison et
14
al reported that obesity as determined by body-weight
>20% of desirable was an independent risk factor for
cardiovascular disease. Jousilhati et al15 reported that
among Finnish men obesity, as determined by BMI, was
an independent risk factor for coronary heart disease
mortality in men and was an important contributor for
mortality in women. In this study a higher
cardiovascular mortality was observed at very low BMI
(<20 kg/m2) which was possibly related to greater
smoking among this group. Calle et al12 studied more
than 1 million adults in United States and reported a Jshaped curve for cardiovascular mortality with BMI with
the lowest mortality found in those with BMI of 23.5626
24.9 in men and 22.0-23.4 in women. The J-curve was
observed for non-smokers as well as smokers although
the highest mortality from cardiovascular diseases was
observed at higher ranges of BMI. The present study
shows that there is a continuous positive relationship
of BMI with cardiovascular risk factors. Prospective
studies among this group are needed to determine the
prognostic importance of these findings.
Results of the European Fat Distribution Study16 and
Paris Prospective Study17 demonstrated importance of
abdominal fat and greater WHR in cardiovascular and
coronary heart disease mortality. Among Indians too,
studies have shown that WHR is an important
cardiovascular risk factor and greater levels are
associated with multiple risk factors.6 However as no
prospective studies exist it is difficult to define cut-off
levels. The present study shows that WHR >0.9 in men
and >0.8 in women is associated with a significant
increase in multiple risk factors. These cut-offs are
similar to those suggested by earlier reports of US
National Cholesterol Education program (ATP-II).11
Importance of waist-size as a marker of cardiovascular
risk factors has not been evaluated in any previous
Indian study. The present study shows that there is a
significant increase in prevalence of hypertension,
diabetes and metabolic syndrome at waist size >90 cm
in men and >80 cm in women. These levels are lower
than those suggested by the US National Cholesterol
Education Program (ATP-III)10 where the cut-off levels
are >102 cm for men and >88 cm for women. Zhou18
reported a meta-analysis of Chinese studies reporting
influence of body-fat on cardiovascular disease mortality.
He suggested a lower cut-off level for diagnosis of obesity
as measured by BMI or WHR. These conclusions are
similar to the observations in the present study.
BMI is the most commonly used indicator of obesity
in population studies, although it is not a perfect one. It
does not take into account body fat patterning as waist
size, WHR and skin-fold measurements do.19 Increased
central or visceral fat independent of relative body weight
is associated with a variety of metabolic disorders and
increased cardiovascular mortality. Furthermore, weight
is usually positively related to increased morbidity and
mortality whereas height is often associated with good
health. Therefore, among obese subjects, the BMI can
reflect the negative effects of both fatness and shortness.
The risks of fatness and shortness are most likely
mediated via different mechanisms. However, BMI also
has several advantages compared with other methods
of measuring obesity. BMI measurement is simple,
inexpensive and reliable. It is widely used and the results
of different studies are therefore easily compared. Results
are also easily transferred for use in practical healthcare
and disease prevention. However, the present study
shows that although BMI predicts accurately the
presence of hypertension, diabetes and metabolic
www.japi.org
© JAPI • VOL. 55 • SEPTEMBER 2007
syndrome, among Indians WHR is a more reliable
indicator of multiple cardiovascular risk factors
including lipid abnormalities. Large prospective studies
are needed to confirm these findings.
The epidemic of obesity is escalating worldwide. The
World Health Report (2002) estimates that currently
overweight is the 10th leading cause of global burden of
diseases following underweight, unsafe sex, blood
pressure, tobacco, alcohol, unsafe water, cholesterol,
indoor pollution and iron deficiency.20 Obesity is a major
determinant of high blood pressure, raised cholesterol
and metabolic syndrome and clearly an important
primordial cardiovascular risk factor. Weight control
should be an integral part of the prevention of
cardiovascular disease. The question of whether obesity
is an independent risk factor for cardiovascular diseases
or whether its effect is mediated via BP, lipid
abnormalities, impaired glucose metabolism, or other
mechanisms is not important in health practice because
mechanisms cannot be separated.4,5 Similarly, although
fat distribution plays an important role in the research
of the pathophysiological mechanisms of obesity and
its relation to other diseases, in practical prevention it
can be used only in individual counselling. In
community-based prevention programs, identification
and use of different subtypes of obesity are difficult. By
preventing overweight in early adulthood it is likely that
a substantial amount of cardiovascular mortality can be
prevented. Message for the urban Indians clearly isLeaner the Better.
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