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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 1, January/February 2015
AFRICA
15
revealed a positive correlation between severity of CAD and
cardiovascular risk factors (Table 3).
On the other hand, our findings regarding the relationship
between WHR and severity of CAD, based on the Duke
myocardial jeopardy score, showed a positive correlation between
the two variables (
p
=
0.03). With increasing WHR, the Duke
score also increased. The relationship between severity of CAD
(Duke score) and WHR is presented in Table 4.
Discussion
In this study, there was a paradoxical relationship between BMI
and severity of CAD but not between WHR and severity of
CAD. Based on the SYNTAX and Duke scores,
β
-coefficients
between BMI and severity of CAD before multivariate analysis
were –0.2 and –0.18, respectively. After multivariate analysis,
they were –0.17.and –0.14, respectively. This shows an inverse
relationship between BMI and severity of CAD.
Controversy regarding the correlation between obesity and
CAD, which surfaced a few decades ago, was the motivation for
us to conduct this study. Although it seems logical that obesity
or adiposity should be accompanied by more accumulation
of fat cells everywhere in the body, including vascular walls
(atherosclerotic plaques), it must be clarified that first of all,
obesity
per se
is not adiposopathy, and second, the process of
atherosclerosis is not a simple process of fat accumulation.
19,20
The process of atherosclerosis is inflammation as a result of
the response to injury in the milieu of high intravascular LDL
cholesterol, especially oxidised LDL. It seems that visceral
adipose tissue is metabolically more active and pathological than
subcutaneous adipose tissue, and induces immunity processes
that contribute to atherosclerotic cardiovascular disease.
21-24
The
answer to the question raised from the obesity paradox is that
atherosclerotic disease does not result from the accumulation
of adipose tissue
per se
but is as a result of adipose tissue
dysfunction, or ‘sick fat’.
19,23,24
Rubinshtein and colleagues (2006), in their study on
928 patients with CAD, showed that obesity had an inverse
relationship with the severity of CAD but other risk factors
such as DM, hyperlipidaemia and male gender were correlated
with the severity of CAD.
11
In another study, published in 2007
by Niraj and colleagues, which was similar to our study, the
relationship between severity of CAD and BMI according to the
Duke score was also paradoxical.
10
Although there are similarities
between our study and theirs regarding the inverse relationship
between patients’ BMI and the severity of CAD, in our study the
relationship between WHR and severity of CAD was evaluated
simultaneously. Surprisingly, in our study, WHR was correlated
with the severity of CAD based on the Duke score.
Moreover, according to the studies of Morricone, Empana
and Zhang, which were published in 1999, 2004 and 2008,
respectively, abdominal adiposity and severity of CAD were
correlated.
12-14
Although their findings were similar to ours
regarding correlation between WHR/abdominal obesity and
severity of CAD, they did not compare BMI with WHR
regarding their impact on the severity of CAD, as we did. These
studies showed that, first, high BMI
per se
was not a risk factor
for CAD, and second, high WHR/abdominal obesity was a
risk factor for CAD. That means abdominal fat accumulation
is more pathological (adiposopathic) than subcutaneous fat
ccumulation.
19,24
Table 1. Basic clinical and demographic
characteristics of patients.
Characteristics
Number (%)
Age, mean
±
SD (years)
61.2
±
27.4
Male gender
250 (60.4)
Diabetes mellitus
113 (27.3)
Hypertension
122 (29.5)
Hyperlipidaemia
162 (39.1)
History of CAD
24 (5.8)
Cigarette smoking
109 (26.3)
History of AP
254 (85.5)
History of MI
85 (20.5)
CAD
=
coronary artery disease, AP
=
angina pectoris, MI
=
myocar-
dial infarction.
Table 2. Correlation between BMI and severity of CAD
(SYNTAX and Duke scores)
BMI
(kg/m²)
Number of
patients (%)
SYNTAX score
(mean
±
SD)
Duke score
(mean
±
SD)
20–24
169 (40.8)
22.3
±
17.2
4.01
±
3.3
25–29
154 (37.2)
16.1
±
14.6
3.05
±
2.5
30–34
83 (20.1)
12.1
±
9.2
2.3
±
1.1
35–39
8 (1.9)
10.8
±
7.04
1.8
±
1.04
p
-value
–
0.01
0.001
BMI
=
body mass index
Table 3. Correlation between cardiovascular risk factors and
severity of CAD (Duke and SYNTAX scores)
Risk factors
Duke score
(mean
±
SD)
p
-value
SYNTAX score
(mean
±
SD)
p
-value
Hypertensives
3.6
±
1.7 0.04 19.1
±
13.1 0.03
Normotensives
2.4
±
1.9
14.9
±
9.5
Cigarette smokers
3.8
±
1.2 0.02 20.8
±
17.4 0.03
Non-smokers
3.07
±
1.4
16.6
±
14.2
Hyperlipidaemics
3.9
±
1.5 0.001 31.5
±
18.05 0.001
Normolipidaemics
2.8
±
1.2
15.3
±
11.02
Diabetics
4.1
±
3.6 0.002 21.5
±
18.4 0.008
Non-diabetics
2.9
±
1.3
16.3
±
9.2
FH positive
4.5
±
3.1 0.07 21.9
±
14.2 0.3
FH negative
3.1
±
2.3
17.5
±
10.4
FH
=
family history.
Table 4. Relation betweenWHR and severity of CAD
based on the Duke score
WHR (mean
±
SD)
Number of patients
Duke score
0.951
±
0.07
165
0
0.954
±
0.06
62
2
0.957
±
0.07
58
4
0.962
±
0.05
54
6
0.971
±
0.05
44
8
0.979
±
0.02
24
10
0.987
±
0.05
6
12
p
-value
0.03
WHR
=
waist-to-hip ratio.