VOLUME 8 NUMBER 4 • NOVEMBER 2011
171
SA JOURNAL OF DIABETES & VASCULAR DISEASE
JOURNAL UPDATE
Journal Update
Southern African contributions
T
he recent UN summit on non-commu-
nicable diseases (NCDs) highlighted the
emerging burden of disease in Africa. Particu-
lar emphasis was paid to preventable lifestyle
choices as risk factors for NCDs, including
tobacco use, unhealthy diet, lack of physi-
cal activity and alcohol abuse. It appears that
the negative consequences of a drift in Africa
towards a Western lifestyle is being com-
pounded by a genetic predisposition towards
the development of NCDs. These factors and
other therapeutic issues are discussed in this
update of relevant articles on southern Africa
from the world literature.
LIFESTYLE
Lifestyle and conventional risk fac-
tors responsible for excess burden
of sub-clinical vascular disease in
black Africans compared to Cauca-
sians in South Africa
There is an emerging burden of cardiovascular
disease among urban black Africans in South
Africa. This rise has been largely explained
by the transition from traditional African life-
styles to more westernised behaviour: more
sedentary routines, smoking and unhealthy
diets, including an excess intake of saturated
fats, highly processed foods and alcohol.
Existing data has generally shown higher
levels of sub-clinical vascular disease in par-
ticipants from lower socio-economic back-
grounds and in blacks. It is difficult to estimate
the true contribution of health behaviour
from self-reported measures alone as these
suffer from considerable reporting bias. From
three health behaviours studied in this article,
alcohol was the most important risk factor
for vascular disease. Low physical activity was
associated with a number of other cardio-
vascular disease (CVD) risk factors, including
body mass index (BMI), triglycerides (TGs),
blood pressure and C-reactive protein (CRP).
The aim of the study was to examine the
role of objectively assesed health behaviours
in explaining the excess burden of sub-clinical
vascular disease seen in urban black Africans
compared to Caucasians. The black (192)
and Caucasian (206) participants were well
matched for age and gender distribution.
In general, the blacks demonstrated more
risk factors, including higher ambulatory
systolic and diastolic blood presure, TGs, BMI,
CRP and a higher prevalence of the metabolic
syndrome. In addition, blacks were less physi-
cally active and more likely to smoke. The
black sample reported lower use of alcohol,
although both black alcohol users and non-
users demonstrated higher levels of gamma
glutamyl transferase than Caucasians. This
might suggest the presence of alcohol-in-
duced liver damage from previous alcohol
abuse in blacks who reported non-drinking
status. Alternatively it may reflect a greater
prevalence of non-alcoholic fatty liver disease
in the blacks.
Results further revealed a higher preva-
lence of hypertension in the black sample.
Black Africans demonstrated higher mean
carotid intima–media thickness (mCIMT)
compared with Caucasians, although the
difference was considerably attenuated
after adjustment for conventional and
behavioural risk factors. This attenuation
suggests that the emerging burden of CVD
among urban black Africans in South Africa
is largely caused by modifiable factors.
Key take-home message:
Higher ambu-
latory systolic and diastolic blood pressure,
and raised triglycerides and body mass index
are the major factors driving vascular disease
in black South Africans.
Source: Hamer M, Malan L,
et al
. Conventional and
behavioural risk factors explain differences in sub-clinical
vascular disease between black and Caucasian South
Africans: The SABPA study.
Atherosclerosis
2011;
215
:
237–242. DOI: 10/1016/j.atherosclerosis.2010.12.015.
South African black smokers demon-
strate greater cardiovascular dys-
function than Caucasian smokers
Globally, the prevalence of smoking-related
CVD is higher in Africans than Caucasians.
Many studies have reported the effect of smok-
ing on the metabolic syndrome, and together
they cause dyslipidaemia, increased CRP levels
and endothelial dysfunction. Smokers are
therefore characterised by high serum TG and
low-density lipoprotein cholesterol (LDL-C),
with significantly lower high-density lipopro-
tein cholesterol (HDL-C) than non-smokers.
Nicotine intake leads to increased blood
pressure and decreased oxygen-carrying
capacity of the blood, which may in turn
cause ischaemia and hypoxia. This stimulates
increased red blood cell production, contrib-
uting to increased viscosity and consequently
inflammatory and coagulatory processes.
Inflammation and coagulation are associated
with atherosclerosis and cornonary heart
disease. All of these factors contribute nega-
tively to increased risk for CVD.
This study aimed to determine the associ-
ation between smoking and measurements
of vascular function in African and Cauca-
sian people of South Africa. Anthropometric
and cardiovascular variables, serum creati-
nine and CRP levels were measured.
African smokers had significantly increased
arterial stiffness, which was not found in Cau-
casian smokers. Africans also showed more
associations between smoking and cardio-
vascular dysfunction than the Caucasians. A
high degree of urbanisation among Africans,
coupled with higher smoking prevalence
might be to blame for the high prevalence of
CVD in the African population.
Key take-home message:
Smoking results
in more vascular damage in black compared
to white South Africans.
Source: Zatu MC, Van Rooyen JM, Schutte AE. Smoking
and vascular dysfunction in Africans and Caucasians from
South Africa.
Cardiovasc J Afr
2011;
22
(1): 18–24.
Xylitol a better sweetener for the
diabetic patient
Chronic consumption or overconsumption
of refined sugar may cause severe physio-
logical and clinical problems such as over-
weight, obesity, diabetes and other diseases
related to the metabolic syndrome. As a
result, sugar substitutes are gaining popular-
ity in the market, several of which have been
found to have mild to severe side effects.
Studies have pointed to the carcinogenic
effects of saccharin in humans; others have
shown aspartame to have significant effects
in causing gastric, pancreatic and endome-
trial cancers and migraines. Aspartame has
also been reported to be responsible for lym-
phomas, leukaemias, cancers of the bladder
and brain, chronic fatigue syndrome, Parkin-
son’s and Alzheimer’s disease, multiple scle-
rosis, autism and systemic lupus.
