Cardiovascular Journal of Africa: Vol 29 No 3 (May/Junel 2018)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 3, May/June 2018 146 AFRICA
Influence of visceral fat and blood pressure on changes
in blood flow velocity in non-obese individuals
A Rahman Rasyada, Munirah Sha’ban, Azran Azhim
Abstract
Introduction: The aim of this study was to evaluate the impact
of different visceral fat (VF) and blood pressure (BP) levels
on changes in blood flow velocity (BFV) among non-obese
subjects, using a cross-sectional study approach.
Methods: A total of 110 putatively healthy and non-obese
subjects were divided into three groups according to their
level of VF and BP. Common carotid artery BFV was meas-
ured using a developed portable Doppler ultrasound meas-
urement system.
Results: The most pronounced peak systolic velocity (S1) was
lower (p < 0.05) in the hypertensive group and the peak dias-
tolic velocity (D) was significantly lower in the pre-hyperten-
sive group than in the normotensive group. There were differ-
ences in velocity reflection and resistive indices between the
hypertensive and other two BP groups. The higher VF group
had significantly lower S1 and D velocities and resistive and
vascular elasticity indices. By contrast, the velocity reflection
index was larger in the higher VF group.
Conclusion: We confirmed that there were significant differ-
ences in the BFV among non-obese subjects who differed
in level of VF and BP. This study confirms that a putatively
increasing VF and BP level is associated with the development
of hypertension.
Keywords: Doppler ultrasound, hypertension, visceral fat, non-
obese, blood flow velocity
Submitted 29/7/16, accepted 19/12/17
Cardiovasc J Afr 2018; 29: 146–149
DOI: 10.5830/CVJA-2018-001
Obesity is one of the well-recognised cardiovascular risk factors for
hypertension, dyslipidaemia and the metabolic syndrome.1-3 Body
mass index (BMI) of 30 kg/m2 as an indicator of obese status is used
as an important indicator of overall body fat.4 However, it is now
increasingly recognised that fat distribution in specific areas can
have more detrimental effects than total body fat.2,3 In particular,
visceral fat (VF) is associated with hypertension, compared to
other fat distributions, including lower body fat and subcutaneous
fat.2 Previous studies have demonstrated that VF is associated with
vascular disease.4-6 Increased VF accumulation contributed to the
development of arteriosclerosis in a normal healthy population7
and coronary artery disease in non-obese patients.6
Numerous studies have demonstrated that Doppler spectral
analysis of blood flow changes with vascular disease.8-10
Rutherhold et al. described the discriminant analysis of peak
systolic (S1), peak diastolic (D) and end-diastolic (d) velocities
in the diagnosis of carotid occlusive disease.8 The accumulation
of high levels of VF contribute to greater aortic stiffness in
older adults as measured by pulse-wave velocity (PWV). 10
Furthermore, cholesterol level was found to have a correlation
with mean blood flow velocity (BFV) and S1 velocity.9,11 It was
suggested that patients with greater common carotid artery
(CCA) plaque and intimal–medial thickness had a high velocity
ratio and increased prevalence of coronary artery disease. 12
Despite the acknowledgment that VF is associated with some
haemodynamic functions, including BP and arterial PWV, the
extent to which VF accumulation has an influence on BFV in
CCA is not well described. Therefore, to clarify the significance
of different VF levels on CCA velocities, non-obese subjects
needed to be studied. In this study, we evaluated the role of
the level of VF and BP on changes in BFV among non-obese
subjects using a cross-sectional study approach.
Methods
The study was performed in 110 (58 males, 52 females) putatively
healthy and non-obese volunteers aged from 18 to 64 years.
Overweight individuals with a body mass index (BMI) of 25 kg/
m2 and obese individuals with a BMI of 30 kg/m2, according to
the World Health Organisation, were excluded from the study.4
The subjects had no overt chronic diseases and did not take any
antihypertensive drugs, as assessed by medical history.
Awritten informed consent was obtained fromall participants.
This study was approved by the research ethics committee of the
International Islamic University of Malaysia.
Three designated VF groups were based on their VF level,
according to the Tanita body composition monitor: lower VF
group (less than level 4), middle VF group (from level 4 to 6) and
higher VF group (level 7 and above). The manual standard of
the Tanita body composition monitor can track visceral fat in the
body ranging from 1 to 59. A rating between 1 and 12 indicates a
healthy level of visceral fat. A rating between 13 and 59 indicates
an excessive level of visceral fat.13
For BP analysis, all subjects were further classified into three
groups based on their systolic (SBP) and diastolic blood pressure
(DBP) measurements: normotensive (SBP < 120 and DBP ≤ 80
Department of Biotechnology, Kulliyyah of Science,
International Islamic University Malaysia, Kuantan, Malaysia
A Rahman Rasyada, MSc (Mol Med)
Department of Physical Rehabilitation Sciences​, Kulliyyah
of Allied Health Sciences, International Islamic University
Malaysia, Kuantan, Malaysia
Munirah Sha’ban, PhD
Department of Biomedical Sciences,​Kulliyyah of Allied
Health Sciences, International Islamic University Malaysia,
Kuantan, Malaysia
Azran Azhim, Dr Eng, PhD (Med Sci), MIEM,