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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 1, January/February 2015
AFRICA
13
Is the relationship of body mass index to severity of
coronary artery disease different from that of waist-
to-hip ratio and severity of coronary artery disease?
Paradoxical findings
Amir Farhang Zand Parsa, Bahareh Jahanshahi
Abstract
Background:
Although for decades there has been controversy
regarding the relationship between obesity and coronary
artery disease (CAD), it has been assumed that high body
mass index (BMI) is a risk factor for CAD. However, the find-
ings of some recent studies were paradoxical.
Objectives:
The aim of this study was to find a relationship
between high BMI and waist-to-hip ratio (WHR) with sever-
ity of CAD.
Methods:
This study was a cross-sectional, prospective study
where 414 patients with suspected coronary artery disease, in
whom coronary angiography was performed, were enrolled.
The mean
±
SD of their ages was 61.2
±
27.4 years (range
25–84), and 250 (60.4%) were male. Regarding cardiovascular
risk factors, 113 (27.3%) patients had a history of diabetes
mellitus (DM), 162 (39.1%) had hypercholesterolaemia, 238
(57.4%) had hypertension, 109 (26.3%) were current smokers
and 24 (5.8%) had a family history of CAD. The mean
±
SD
of the patients’ BMI was 26.04
±
4.08 kg/m
2
(range 16–39)
and means
±
SD of their WHR ranged from 0.951
±
0.07 to
0.987
±
0.05. The mean
±
SD of the severity of CAD accord-
ing to the SYNTAX and Duke scores were 17.7
±
9.6 (range
0–64) and 3.2
±
1.7 (range 0–12), respectively.
Results:
In this study, findings showed a negative correlation
between the severity of CAD and BMI, according to both
SYNTAX and Duke scores (
p
≤ 0.001 and
p
=
0.001, respec-
tively). However, there was a positive correlation between
WHR and severity of CAD, according to the Duke score (
p
=
0.03).
Conclusion:
BMI had a negative correlation with the severity
of CAD, but waist-to-hip ratio had a positive correlation with
severity of CAD.
Keywords:
body mass index, waist-to-hip ratio, coronary artery
disease, SYNTAX score, Duke score
Submitted 25/4/14, accepted 21/8/14
Cardiovasc J Afr
2015;
26
: 13–16
www.cvja.co.zaDOI: 10.5830/CVJA-2014-054
Although obesity has been regarded as an independent risk
factor for coronary artery disease (CAD) by the American Heart
Association (AHA) and investigators of the Framingham Heart
study in the 1980s and 1990s,
1-3
this has not been supported by
recent clinical trials. Moreover, the positive linear relationships
between obesity and CAD, as reported by some studies, were as
a result of univariate analysis of their data. However, by using
multivariate analysis of these study data, which included other
cardiovascular risk factors such as diabetes mellitus (DM),
hypertension (HTN) and hyperlipidaemia, this relationship was
shown to be dramatically reduced.
4,5
In the Munster Heart study (PROCAM) and similar studies,
the positive relationship between body mass index (BMI)
and cardiovascular risk factors, with cardiac mortality, which
attributed obesity as an independent risk factor, appeared to
be due to the associated cardiovascular risk factors that usually
accompany obesity.
6-10
In these studies there was also a strong
positive correlation between high BMI and other cardiovascular
risk factors.
However, findings of recent studies in this regard were
opposite to those of previous studies. According to their findings,
not only was obesity not a risk factor for CAD but it also had a
protective effect on the progression of CAD, which is known as
the ‘obesity paradox’.
11,12
On the other hand, abdominal adiposity
has always been associated with increased cardiovascular disease
and mortality rate, independent of patients’ weight.
13,14
This study was designed to evaluate not only the impact of
BMI but also waist-to-hip ratio (WHR) on the severity of CAD,
based on angiographic findings.
Methods
This study was a cross sectional, prospective study that was
conducted in our hospital from September 2009 to March 2011.
A total of 414 patients with suspected CAD were enrolled in
the study. Patients’ mean age
±
SD was 61.2
±
27.4 years (range
24–84) and 250 (60.4%) patients were male.
Coronary angiography was done on all patients. The severity
of CAD was measured using the SYNTAX score (the sum of the
points assigned to each individual lesion identified in the coronary
arteries with
>
50% stenosis in vessels
>
1.5 mm diameter). The
SYNTAX score, a lesion-based angiographic scoring system,
was introduced as a tool to grade the complexity of CAD. It
was derived from a combination of the AHA classification for
coronary artery segments with various other scores,
15,16
and the
Duke jeopardy scores (Fig. 1A). The Duke jeopardy score is a
simple, effective scoring system for quantifying the amount of
myocardium at risk. The Duke jeopardy score, developed by
Division of Cardiology, Imam Khomeini Hospital Complex,
Tehran University of Medical Sciences, Tehran, Iran
Amir Farhang Zand Parsa, MD,
zandparsa@tums.ac.irBahareh Jahanshahi, MD