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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
34
VOLUME 14 NUMBER 1 • JULY 2017
These authors reported a strong association between
atherosclerosis, hyperhomocysteinaemia and type 2 diabetes in the
Japanese population. They concluded that hyperhomocysteinaemia
in diabetes mellitus may contribute to the development of chronic
complications. Vayá
et al
. established a borderline statistically
significant association (
p
= 0.008) between hyperhomocysteinaemia
and hyperglycaemia (
p
= 0.054).
15
Hypertension is a condition where the artery walls are stiffer
and present increased resistance to blood flow. This requires the
heart to beat more forcefully and increases the pressure of blood
leaving the heart. High blood pressure is often called the silent killer
because in the initial stages it presents with no symptoms. It is only
after an organ in the body has been irritated or damaged, that the
consequences of high blood pressure are realised.
16
Hypertension places stress on the target organs, including
kidneys, eyes and heart, causing them to deteriorate over time.
Hypertension contributes to 75% of all strokes and heart attacks.
17
One in three African-Americans has hypertension. One African-
American dies every hour from the disease, and more than 30% of
African-Americans can count hypertension or its complications as
the leading cause of death.
17
The hypothesis that homocysteine may play a role in the
pathogenesis of essential hypertension is based on the fact that
homocysteine induces arteriolar constriction, renal dysfunction
and increased sodium reabsorption, increasing arterial stiffness.
18
Homocysteine increases oxidative stress, which causes oxidative
injury to the vascular endothelium, diminishing vasodilation by
nitric oxide, stimulating proliferation of vascular smooth muscle
cells and altering the elastic properties of the vascular wall, leading
to an increase in hypertension.
18
These authors concluded that
homocysteine may contribute to blood pressure elevation. Atif
et
al
. observed that plasma homocysteine was raised in most patients
with hypertension.
19
The authors found in their study that 80% of
their hypertensive subjects were hyperhomocysteinaemic.
Karatela and Sainani found a high prevalence of hyper-
homocysteinaemia associated with raised blood pressure, with raised
systolic and diastolic pressures.
10
Nabipour
et al
. reported significantly
higher homocysteine levels in subjects with high blood pressure.
20
Vayá
et al
. however found no statistically significant association (
p
= 0.008) between hyperhomocysteinaemia and hypertension (
p
=
0.229).
15
In large community-based studies, plasma homocysteine was
found to be cross-sectionally associated with blood pressure,
especially systolic pressure, unadjusted for gender and age.
21,22
The authors however found that adjusted for gender and age, the
relationship of plasma homocysteine to the incidence of hypertension
was statistically non-significant.
Experimental investigations evaluating the association of
homocysteine and blood pressure have not yielded consistent results.
Diet-induced hyperhomocysteinaemia has been demonstrated to
elevate blood pressure in some investigations but to lower it in
others.
21
A positive association of total homocysteine with both
systolic and diastolic blood pressure was reported in several clinical
cross-sectional studies.
21
These authors found no major relationship
between baseline plasma homocysteine level and incidence of
hypertension.
Lipids are a group of organic compounds that include, among
others, cholesterol, triglycerides, phospholipids, lipoprotein and
sterols, which are insoluble in water but soluble in non-polar organic
solvents.
23
Fats (solid lipids) constitute approximately 34% of the
energy used in the human body.
24-26
Of the lipids, triglycerides and
cholesterols [very low-density lipoprotein (LDL), LDL and high-density
lipoprotein (HDL) cholesterol] are the components that play a major
role in atherosclerosis, the forerunner of arteriosclerosis.
27
All body cells are capable of LDL cholesterol (LDL-C) synthesis.
This favours deposition of cholesterol in the cells and blood vessels.
LDL-C is therefore atherogenic. HDL transports cholesterol from the
cells to the liver for degradation into bile salts (sodium taurocholate
and deoxycholate).
23
HDL-C is therefore anti-atherogenic and
protective against the development of atherothrombosis.
High triglyceride levels are significant risk factors for cardiovascular
disease and are a marker for atherogenic remnant lipoprotein, such
as very LDL-C. Even in the presence of tightly controlled LDL-C
levels, evidence indicates that high triglyceride levels and low HDL-C
levels are independent thrombosis and cardiovascular risk factors.
28
About half of all deaths in developed countries are caused by
homocysteinaemia and dyslipidaemia (hypercholesterolaemia and
hypertriglyceridaemia).
29
According to Rima andWolfgang, there is an association between
hyperhomocysteinaemia and dyslipidaemia, and diabetes mellitus is
common to hyperhomocysteinaemia and hypercholesterolaemia.
30
Vayá
et al
. found no statistically significant association (
p
= 0.008)
between hyperhomocysteinaemia and low HDL-C levels (
p
= 0.491)
and hypertriglyceridaemia (
p
= 0.490).15 However, Nabipour
et al
.
found subjects with lower HDL-C levels had higher homocysteine
levels (
p
= 0.001).
20
Obesity is characterised by excess body fat due to an imbalance
between calorie intake and expenditure. Causes of obesity include
high calorie intake, lack of exercise and genetic susceptibility or
psychiatric illness.
31
Obesity is defined as a body mass index (BMI)
greater than 30 kg/m
2
.
32
Two patterns of obesity are central (visceral) obesity and peripheral
obesity. The former is more common in males and carries a higher
risk of coronary heart disease, as well as various forms of metabolic
derangement, including dyslipidaemia and impaired glucose
tolerance. Peripheral obesity is when fat accumulates in the gluteo-
femoral area. It is more common in women but less associated with
cardiovascular risk, as a complication of arterial thrombosis.
33
Obesity
is an independent risk factor for the complications of atherosclerotic
vascular disease, such as myocardial infarction and stroke and has
been found to elicit and increase the risk of arterial thrombosis.
6,34
Obesity affects about 1.3 billion people worldwide, and 3.0 to
20.4% of South African males and 25.9 to 54.3% of females.
32,35
Karatela and Sainani observed an increased prevalence of
hyperhomocysteinaemia in overweight and obese subjects.
10
Nabipour
et al
. found no significant association between
homocysteine level and BMI in a study of the relationship between
the metabolic syndrome and homocysteine levels.
20
However, Vayá
et al
. found in four studies that increased homocysteine levels were
related mostly to abdominal obesity.
15
Sanlier and Yabanci found increased body weight to be associated
with hyperhomocysteinaemia, but without gender differences.
36
El-Sammak
et al.
also found hyperhomocysteinaemia to increase
with age, possibly because of the presence of other factors that
raise plasma total homocysteine levels with age, especially increased
deterioration in other organ functions.
37
Methods
The study was cross-sectional and prospective. Participants were
recruited by trained field workers and consented voluntarily in