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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 5, September/October 2016
AFRICA
323
Surprisingly, in 2014, the World Health Organisation reported
an absence of operational policies or action plans to reduce the
risk factors for CVD. This is in spite of the goodwill adopted by
world leaders at the United Nations General Assembly to reduce
premature mortality from non-communicable diseases by 25%
in 2025.
4
Curtailing the challenge of CVD requires knowledge of its
burden and risk factors, committed and effective socio-political
interventions, and inexpensive strategies. This has contributed to
the gradual and sustained decline in mortality in high-income
countries.
This study therefore set out to determine the prevalence
and pattern of clustering of risk factors, as this will effectively
influence formulation of policies to curb detrimental health
consequences in developing countries such as Nigeria. It was also
of importance to determine whether clustering of cardiovascular
risk factors occurs in patients from the semi-urban areas that
access medical treatment from the hospitals where we practice,
so we can subvert the imminent cardiovascular disease epidemic.
Methods
This was a cross-sectional study spanning seven months,
conducted in 11 semi-urban communities in Ekiti and Osun
States, south-western Nigeria. Each of the towns was randomly
picked from six local government areas (two communities
per local government area). Using multi-staged sampling,
participants aged 18 years and older were enrolled into the study.
In Osun state, Ilie in Olorunda local government was chosen.
The local governments and towns chosen in Ekiti state were
Ilejemeje (Iludun, Ilupeju), Ijero (Ayegunle, Oke-Iro), Ido-Osi
(Ayetoro, Orin), Oye (Ilupeju, Itapa) and Moba (Osun, Ikun). In
Ilie for instance, there were 32 compounds, out of which 16 were
randomly selected. Out of these 16 compounds, eight were finally
selected for the study. For some of the communities, convenient
sampling was adopted for the peculiarities of these communities.
The towns were predominantly agrarian with traders and few
civil servants. Four hundred and sixty-eight and 835 participants
were recruited from Osun and Ekiti states, respectively. Of the
1 285 enrolled in the study, 1 083 had complete data for analysis.
The community leaders had given prior consent after formal
briefing in the presence of other chiefs who were the compound
leaders. Informed consent was taken in the language best
understood. The study was approved by the ethics committees of
Ladoke Akintola University of Technology Teaching Hospital
and Federal Medical centre, Ido-Ekiti.
Designated centres that were convenient for the subjects
were used for the screening exercise. We used the World
Health Organisation (WHO) STEPS questionnaires to obtain
information from the participants.
Sampling
Fasting blood samples (3 ml) were collected into lithium heparin
bottles. Aseptic precautions were ensured. Fasting blood sugar
was assayed with an Accu-check glucometer immediately after
blood collection. The measuring range of the device for glucose
is 50–600 mg/dl. Samples were thereafter taken to the chemical
pathology laboratory of the Federal Medical Centre, Ido-Ekiti
and Ladoke Akintola Teaching Hospital, Osogbo for analysis.
Samples were analysed for concentrations of total cholesterol
(TC), high-density lipoprotein cholesterol (HDL-C), triglycerides
(TG) and uric acid. For participants with TG values
<
4.5 mmol/l,
low-density lipoprotein cholesterol (LDL-C) was calculated
from the Friedwald equation: LDL-C
=
(TC – HDL-C – TG)/5.
Administration of questionnaires, biophysical measurements
and collection of blood specimen was done by trained assistants
who were also medical doctors.
Three measurements were taken after the participants had
rested for five minutes. Participants were encouraged not
to smoke, take alcohol or undertake exercise for at least 30
minutes before blood pressure measurement. Validated blood
pressure apparatus (Omron M X2 Basic, Omron health care Co
Ltd, Kyoto, Japan) was used. The average of two measurements
was used if the difference between them was not more than
5 mmHg.
Height was measured to the nearest 0.1 cm using a
standardised, marked measuring tape. Participants were asked to
stand barefoot against a tape-marked vertical wall. Weight was
measured to the nearest 0.1 kg using a standardised bathroom
scale. Waist circumference was taken midway between the
sub-costal margin and the iliac crest, to the nearest 0.1 cm.
Definitions
Cardiovascular disease refers to a group of diseases involving
the heart and blood vessels or the sequelae of poor blood supply
due to a diseased vascular system. Hypertension was defined as
blood pressure
≥
140/90 mmHg or the use of antihypertensive
medication(s). Diabetes was defined as a fasting plasma glucose
level
≥
7 mmol/l or a reported history of diabetes, or the use of
glucose-lowering drugs.
Dyslipidaemia was defined according to the Adult Treatment
Panel (ATP) III guidelines
14
as having one or more of the
following factors present: TC
≥
5.2 mmol/l, TG
≥
1.7 mmol/l,
HDL-C
<
1.03 mmol/l in men and
<
1.30 mmol/l in women,
LDL-C
≥
3.4 mmol/l, or a history of medication with lipid-
lowering drugs. High atherogenic index was defined as TC/
HDL-C
≥
5.
Indices of abnormal fat distribution were also defined
according to the ATP III guidelines as waist circumference
(WC)
≥
94 cm in men and
≥
80 cm in women; and body mass
index (BMI)
≥
25 kg/m
2
as overweight and
≥
30 kg/m
2
as obese.
Participants with high blood pressure or symptomatic diabetes
were referred to hospital for treatment and encouraged to go for
follow up.
Statistical analysis
Data analysis was done using SPSS version 20.0 (SPSS
Inc, Chicago, Illinois, USA). The prevalence of each of the
cardiovascular risk factors was determined and they are
presented as frequencies and percentages. Continuous variables
are presented as mean
±
SD while categorical variables are
presented as frequencies and percentages. The prevalence of
risk factors in clusters of two, three or more was determined.
Multivariate analysis of risk factors associated with two or more
risk factors was carried out and the results are expressed as odds
ratios with 95% confidence interval (CI). A significance level of
p
<
0.05 was used.