CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 5, September/October 2011
AFRICA
249
The relationship between indices of iron status and
selected anthropometric cardiovascular disease risk
markers in an African population: the THUSA study
OR ADERIBIGBE, PT PISA, RL MAMABOLO, HS KRUGER, HH VORSTER
Abstract
There is evidence that certain indices of iron status are
associated with anthropometric measures, which are used
independently as markers of cardiovascular disease (CVD)
risk. This study examined whether this association exists
in an African population. The study was a cross-sectional
comparative study that examined a total of 1 854 African
participants. Ferritin was positively associated with body
mass index (BMI), waist circumference (WC), waist-to-hip
ratio (WHR), percentage body fat and subscapular skin-
fold thickness. Serum ferritin concentration was higher in
the high-WHR category than the normal-WHR category
for both genders. Additionally, WC and WHR increased
with increasing ferritin concentrations in both genders.
Serum iron was lower in the obese than the normal-weight
and pre-obese women only. In this population-based study,
increased serum ferritin concentrations associated positively
with increased WHR and WC, indicating that individuals or
populations at risk of iron overload as defined by high serum
ferritin concentrations may be at a greater risk of developing
CVD.
Keywords:
iron indices, anthropometry, cardiovascular diseases,
African, THUSA study
Submitted 13/7/10, accepted 15/4/11
Published online 10/5/11
Cardiovasc J Afr
2011;
22
: 249–256
DOI: 10.5830/CVJA-2011-015
South Africa is experiencing a health transition, associated with
a triple burden of disease characterised by a high prevalence
of undernutrition-related infectious diseases, the emergence of
non-communicable diseases, and the human immunodeficien-
cy virus/acquired immune deficiency syndrome (HIV/AIDS)
pandemic.
1
Micronutrient deficiencies still remain a major public
health challenge in most developing countries. Iron-deficiency
anaemia is the most common nutritional deficiency in the world
and it has negative consequences for growth and health.
2,3
The
prevalence of iron deficiency is highest in developing countries
and its causes are multi-factorial.
4
In South Africa, anaemia has
been reported in seven to 29% of pregnant women
5-7
and 57%
of pregnant teenage girls.
8
The World Health Organisation
2
esti-
mated that 26.4% of non-pregnant women of reproductive age in
South Africa had haemoglobin concentrations below 12
µ
g/dl.
Charlton
9
also reported a 13% prevalence of anaemia among an
elderly South African population.
Iron is a key element in many biochemical processes and
shortage of iron causes damage to cells and organs. On the other
hand, excess iron could be harmful because it is able to catalyse
the formation of highly reactive oxygen and hydrogen radicals
when present in the unbound state.
10
Because of the ease with
which additional iron can be provided to iron-replete individuals
through iron-fortified foods or iron supplements, and the limited
ability to excrete the mineral, the consequences of iron excess
are as relevant nutritionally as the liabilities of iron deficiency.
A high prevalence of iron overload (15%) was reported among
black males across sub-Saharan Africa who customarily drink
a traditional fermented beverage with a high iron content.
10
A
genetic predisposition to iron overload has also been identified
in Africans.
10
Due to rapid urbanisation, lifestyle changes and the adop-
tion of Western diets, obesity has become a growing problem
in developing countries. Countries undergoing transition, such
as China, Brazil and South Africa are particularly affected and
have an increasing prevalence of obesity across all economic
levels and age groups.
11
In South Africa, 30% of men and 55% of
women have been classified as overweight or obese.
12
Cross-sectional studies have indicated that measures of iron
status are positively associated with cardiovascular disease
(CVD) risk factors, and this association is hypothesised to be
mediated by adiposity.
14,15
Additionally, iron deficiency has been
reported to be positively associated with anthropometric indica-
tors such as waist circumference (WC), body mass index (BMI)
and waist-to-hip ratio (WHR),
13,14
which are now used indepen-
dently as markers for CVD risk.
15
Establishing the relationship
between measures of iron status and these anthropometric CVD
risk markers may give an indication whether the iron status of a
population can predict its CVD risk. In view of this, the present
study was aimed at examining the relationship between measures
of iron status (ferritin, serum iron and haemoglobin concentra-
tions, total iron-binding capacity and percentage transferrin
saturation) and selected anthropometric CVD risk markers in an
African population.
Methods
The THUSA (Transition and Health during Urbanisation of
South Africans) study was conducted from 1996 to 1998 in the
North West province of South Africa.
16
It was a cross-sectional
comparative study in which a community-based sample of 1 854
Centre of Excellence for Nutrition, Faculty of Health
Sciences, North-West University, Potchefstroom, South
Africa
OR ADERIBIGBE, MSc,
or connecttolaide@
yahoo.com
PT PISA, PhD
RL MAMABOLO, PhD
HS KRUGER, PhD
HH VORSTER, DSc
