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SA JOURNAL OF DIABETES & VASCULAR DISEASE
RESEARCH ARTICLE
VOLUME 14 NUMBER 1 • JULY 2017
29
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
Correspondence to: Amir Farhang Zand Parsa, Bahareh Jahanshahi
Division of Cardiology, Imam Khomeini Hospital Complex,
Tehran University of Medical Sciences, Tehran, Iran
e-mail:
zandparsa@tums.ac.irPreviously published in
Cardiovasc J Afr
2015;
26
: 13–16
S Afr J Diabetes Vasc Dis
2017;
14
: 29–32
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
findings 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 patientswith 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 according 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,
respectively). 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
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