CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 1, January/February 2014
AFRICA
27
Prevalence of the metabolic syndrome and
determination of optimal cut-off values of waist
circumference in university employees from Angola
Pedro Magalhães, Daniel P Capingana, José G Mill
Abstract
Background:
Estimates of the prevalence of the metabolic
syndrome in Africans may be inconsistent due to lack of
African-specific cut-off values of waist circumference (WC).
This study determined the prevalence of the metabolic
syndrome and defined optimal values of WC in Africans.
Methods:
This cross-sectional study collected demographic,
anthropometric and clinical data of 615 Universitary employ-
ees, in Luanda, Angola. The metabolic syndrome was defined
using the third report of the National Cholesterol Education
Program Adult Treatment Panel (ATPIII) and the Joint
Interim Statement (JIS) criteria. Receiver operating character-
istics curves were constructed to assess cut-off values of WC.
Results:
The crude prevalence of the metabolic syndrome
was higher with the JIS definition (27.8%, age-standardised
14.1%) than with the ATP III definition (17.6%, age-stand-
ardised 8.7%). Optimal cut-off values of WC were 87.5 and
80.5 cm in men and women, respectively.
Conclusions:
There was a high prevalence of the meta-
bolic syndrome among our African subjects. Our data suggest
different WC cut-off values for Africans in relation to other
populations.
Keywords:
metabolic syndrome, waist circumference, Africans,
Angola
Submitted 3/4/13, accepted 9/12/13
Cardiovasc J Afr
2014;
25
: 27–33
DOI: 10.5830/CVJA-2013-086
The metabolic syndrome is characterised by the presence of
multiple metabolic risk factors for cardiovascular (CV) disease
1
and type 2 diabetes mellitus.
2
In clinical practice, the metabolic
syndrome is diagnosed by combinations of three or more of
the following five risk factors: central obesity, elevated blood
pressure, glucose intolerance, hypertriglyceridaemia and low
high-density lipoprotein cholesterol (HDL-C).
3-6
Worldwide the prevalence of the metabolic syndrome is
increasing and becoming a pandemic, and this increase has been
mainly attributed to sedentary lifestyle and obesity.
7
However,
levels of prevalence may vary greatly according to cut-off points
of diagnostic criteria and the ethnic group studied.
8
In sub-Saharan Africa, the majority of countries are
experiencing a rapid demographic and epidemiological
transition.
9,10
Available information from studies in African
populations reported a prevalence of the metabolic syndrome
ranging from 0% to as high as about 50% or more, depending on
the population setting.
11
These data however, are limited to some
countries,
12-21
since there are no available data for the majority of
African countries.
Angola is a country in sub-Saharan Africa, which in the
last few years has undergone significant political changes,
accompanied by a rapid economic growth and increased
urbanisation. These changes may imply an increasing prevalence
of factors contributing to the metabolic syndrome, such as
obesity, insufficient physical activity, dyslipidaemia, high blood
pressure and glucose intolerance. However, the prevalence of the
metabolic syndrome and which factors contribution more to its
occurrence in the Angolan population remain unknown.
Despite the efforts of several organisations to regulate the
algorithm for a definition of the metabolic syndrome,
3-5
there
is inconsistency on cut-off levels of waist circumference (WC)
for defining the metabolic syndrome in several populations.
The International Diabetes Federation (IDF)
5
recommended the
use of ethnic or country-specific cut-off values of WC for the
majority of populations, a recommendation reinforced in the
Joint Interim Statement (JIS),
7
which tried to define different
criteria for a definition of the metabolic syndrome.
These cut-off values were defined using different methods.
For example, Western countries derived their cut-off values of
WC from a correlation with body mass index (BMI),
4,22
whereas
Asian groups tried to define WC cut-off values yielded by
receiver operating characteristics (ROC) curve analyses.
23
Due
to a lack of specific data from African populations, cut-off
points of WC derived from the European population have been
recommended,
5,7
although emerging data suggest that African-
specific cut-off values would be different from the European
cut-off points currently recommended by the IDF.
18,24,25
Therefore,
definition of a more reliable cut-off point for WC is needed to
build a consistent tool for diagnosis of the metabolic syndrome
in sub-Saharan African populations.
The aim of this study was to determine the prevalence of the
metabolic syndrome in a sample of Africans from Angola, using
either the third report of the National Cholesterol Education
Program Adult Treatment Panel (ATP III)
4
or the JIS
7
criteria.
Additionally, this study tried to identify threshold WC levels that
best predict other components of the metabolic syndrome.
Department of Physiology, Faculty of Medicine, University
Agostinho Neto, Luanda, Angola
Pedro Magalhães, MD, PhD,
Daniel P Capingana, MD, PhD
Department of Physiology, Federal University of Espírito
Santo, Vitoria, Brazil
José G Mill, MD, PhD
