Prevalence of Metabolic Syndrome and its Individual Components among Diabetic Patients in Ghana
Felix-Val K. Titty,
W.K. B.A. Owiredu
M. T. Agyei-Frempong
The aim of this study was to determine the prevalence of metabolic syndrome
and its individual components in diabetic patients in Ghana. This prospective
study included 456 diabetic patients and was conducted at the Komfo Anokye
Teaching Hospital in the Ashanti Region of Ghana from January 2006 to
May 2007. Metabolic syndrome was defined according to the National Cholesterol
Education Programme Adult Treatment Panel 3 diagnostic criteria. The prevalence
of metabolic syndrome was 55.9% in the studied population. Low HDL cholesterol
was the commonest component (47.4%) of metabolic syndrome, followed by
hypertension (46.9%). Female diabetic patients had higher prevalence of
metabolic syndrome and its components and individually carried more components
than male diabetics. Future cardiovascular disease (CVD) prevention strategies
in Ghana should not overlook metabolic disease risk factors.
Today, there is a growing interest in a cluster of synergistically interacting
cardiovascular risk factors called metabolic syndrome, which is mainly
characterized by insulin resistance, hyperglycaemia, dyslipidaemia, hypertension
and abdominal (central) obesity (NCEP ATPIII, 2001). The syndrome is increasingly
recognized as a risk factor for diabetes mellitus, CVD (Ford et al.,
2002; Isomaa et al., 2001) and cardiovascular mortality (Trevisan
et al., 1998). Disturbances such as microalbuminuria, endothelial
dysfunction, abnormalities in fibrinolysis and coagulation, nonalcoholic
fatty liver and elevated markers of chronic inflammation have lately been
linked to metabolic syndrome (Yudkin, 1999; Steinberg et al., 1996;
Groop et al., 1993; Laaksonen et al., 2004). Two main different
sets of criteria have been put forth for the definition of metabolic syndrome;
one by the World Health Organization (WHO) (Aberti and Zimmet, 1998) and
a related but not identical definition from the National Cholesterol Education
Programme Expert Panel on Detection, Evaluation and treatment of high
blood cholesterol in adults, Adult Treatment Panel 3 (NCEP ATPIII) (2001).
Disease risk is directly affected by genetics and also by life style factors
such as diet and exercise patterns. Thus prevalence varies by race/ethnicity
and other predictor variables (Park et al., 2003) and hence from
one country or area to the other. The prevalence of metabolic syndrome
in the adult diabetic population of the Republic of Cyprus by the NCEP
ATP III criteria (Loizou et al., 2006) was found to be 68.5%. Limited
information is available on the prevalence of metabolic syndrome and its
individual components among diabetic patients in Ghana. Thus the objective
of this study was to determine the prevalence of metabolic syndrome and
its individual components among diabetic patients in Ghana by the NCEP
MATERIALS AND METHODS
This study was carried out at the School of Medical Sciences, Kwame Nkrumah
University of Science and Technology (KNUST) Komfo Anokye Teaching Hospital
(KATH) Kumasi in the Ashanti region of Ghana. This was a prospective study
covering the period from January 2006 to May 2007. All written study protocols
were approved by the Committee for Human Research Publications and Ethics
of KNUST. All participants consented to participate in the research. Diabetic
patients on insulin and/or diet with oral hypoglycaemic drugs were consecutively
selected until a sample size of 456 was achieved. Diabetes was defined
according to the WHO criteria (Alberti and Zimmet, 1998). A standardized
questionnaire and patient medical history folders were used to collect
information on demographic and clinical characteristics such as age, sex,
ethnicity (tribe), duration of diabetes, age of onset and family history
of diabetes and hypertension. Others included stress, diabetes and hypertension
medication profile and other physician-diagnosed diseases. Height and
weight were measured with subjects wearing lightweight clothing and without
shoes and Body Mass Index (BMI) calculated (kg m-2). Waist
circumference was measured with a plastic anthropometric tape on bare
skin of standing subjects during midrespiration at the bending point and
at the narrowest indentation, midway between the lowest rib and the iliac
crest and at the level of the umbilicus to the nearest 0.1 cm. Systolic
and diastolic blood pressures were obtained with a mercury sphygmomanometer
and auscultory methods. Two blood pressure recordings were obtained from
the right arm of each patient in a sitting position, after 30 min of rest
at 5 min intervals and their mean value calculated. Blood specimens were
obtained after 12 to 14 h overnight fast. Fasting glucose, triglycerides
and HDL cholesterol were measured by enzymatic methods using the procedures
of ATAC PAK glucose reagent kits (product No. 532-018) USA, ATAC PAK triglyceride
reagent kits (product no. 589-018) USA, ATAC PAK HDL cholesterol reagent
kits (product No. 541-004) USA and ATAC 8,000 Random Access Chemistry
System (autoanalyzer elan diagnostics, A4-001-1198), USA. The procedures
for glucose, triglycerides and HDL cholesterol are described by the manufacturer
in the ATAC 8,000 Random Access Chemistry System Operator`s Manual (1998
and 1999). Metabolic syndrome was diagnosed using the NCEP ATPIII (2001)
criteria, that is, the presence of three or more of the following factors:
(1) Central obesity, i.e., waist circumference in males >102 cm and
in females >88 cm, (2) Triglycerides = 1.70 mmol L-1, (3)
HDL cholesterol in males <1.00 mmol L-1 and in females <1.30
mmol L-1, (4) Blood pressure≥130/85 mmHg or on antihypertensive
medication and (5) Fasting glucose >6.1 mmol L-1. All patients
in this study were coded as positive for hyperglycaemia (i.e., glucose
≥ 6.1 mmol L-1). Metabolic score was calculated as the number
of metabolic syndrome factors each patient fulfilled. Statistical analyses
were performed using the Statistical Package for Social Sciences (SPSS)
for windows programme version 11.0. Student`s t-test was used for comparing
mean differences of continuous variables to determine the statistical
significance. The χ2 test was used to determine the statistical
significance of differences in proportions. A p-value of less than 0.05
was considered significant.
The study population comprised 456 diabetes mellitus patients, made up
of 141 (30.9%) males and 315 (69.1%) females. The selected diabetic population
included 250 (54.8%) Twi-speaking peoples, 30 (6.6%) Fantes, 38 (8.3%)
Guans, 40 (8.8%) Ga-Adangbes, 66 (14.5%) Northern peoples, 23 (5.0%) Ewes
and others 9 (2.0%) who belonged to other minor tribes that could not
be distinctly classified. The distribution shows that all the major tribes
of Ghana were fairly represented. The mean age of the patients was 55.8±12.3
years. The mean age of onset of the patients was 49.7±12.4 years.
The mean duration of diabetes was 6.0±3.5 years. The mean BMI was
25.1±4.8 kg m-2. The corresponding values in males and
females are indicated in Table 1. Male and female values
for age, age of onset, duration of diabetes and BMI were not significantly
(p = 0.52, 0.91, 0.45 and 0.27 respectively) different (Table
||Clinical characteristics of diabetic patients
Prevalence of metabolic syndrome and its components in diabetic
patients in Ghana
||Metabolic score of diabetic patients in Ghana
Prevalence of the metabolic syndrome and its components were calculated
in the male, female and the overall diabetic patients. Metabolic syndrome
was observed in 255 (55.9%) patients including 47 (33.3%) males and 208
(66.0%) females. Table 2 shows that 199 (43.6%) diabetic
patients had central obesity, made up of 19 (13.5%) males and 180 (57.1%)
females; 171 (37.5%) patients had hypertriglyceridaemia, consisting of 51
(36.2%) males and 120 (38.1%) females. Low HDL cholesterol was observed
in 216 (47.4%) patients, made up of 49 (34.8%) males and 167 (53.0%) females
(Table 2). Among the same group of patients, 214 (46.9%)
had blood pressure ≥ 130/85 mmHg and/or on hypertensive medication, consisting
of 56 (39.7%) males and 158 (50.2%) females (Table 2).
In addition to hyperglycaemia, low HDL cholesterol was the commonest component
(47.4%) of metabolic syndrome among diabetic patients in Ghana, followed
by hypertension (46.9%). In females central obesity (57.1%) was the commonest
component, followed by low HDL cholesterol (53.0%). In males, hypertension
(39.7%) was the commonest component, followed by hypertriglyceridaemia (36.2%).
Metabolic scores were calculated in the male, female and the overall diabetic
patients. Table 3 demonstrates that 26 (5.7%) patients
had a metabolic score (metabolic syndrome factors) of five; 99 (21.7%) a
metabolic score of four; 131 (28.7%) had three factors; 134 (29.4%) had
two factors; and 66 (14.5%) had one factor. The corresponding values for
males and females are also shown in Table 3.
Metabolic syndrome has attracted much attention as a risk cluster for
CVD in type 2 diabetes (Isomaa et al., 2001), non diabetic subjects
(Lakka et al., 2002) and recently in type 1 diabetes (Thorn et
al., 2005). The NCEP ATPIII criteria of metabolic syndrome were chosen
to assess the prevalence of metabolic syndrome. This is because the NCEP
ATPIII proposal, but not the WHO criteria, more clearly identifies the
burden of coronary heart or cerebrovascular disease associated with metabolic
syndrome and it is associated with a 38% increased risk (Marchesini et
al., 2004; Scuteri et al., 2005). Metabolic syndrome was found
in more than half (55.9%) of the Ghanaian diabetes mellitus patients (both
types 1 and 2). It was more prevalent (P = 0.001) in female diabetics
(66.0%) than in males (33.3%). Individuals with metabolic syndrome are
at increased risk for coronary heart disease (CHD) (Lakka et al.,
2002). Once detected vigorous and early management of the metabolic syndrome
may have a significant impact on the prevention of CVD (Eriksson and Lindegard,
1991). The prevalence of metabolic syndrome in the adult diabetic population
of the Republic of Cyprus (68.5%) by the NCEP ATPIII criteria (Loizou
et al., 2006) was only slightly higher than the value of 55.9%
obtained among Ghanaian diabetics in this study. This could be explained
by the differences in the prevalence of the components of metabolic syndrome
between different ethnic groups.
In the total diabetic population (i.e., both types 1and 2 diabetes),
low HDL cholesterol was the commonest component of metabolic syndrome
in the diabetic patients in Ghana. Knowing the commonest risk factor in
different populations will give a guide to prevention and treatment. These
results are in fair agreement with those of Al-Lawati et al. (2003),
who using the NCEP ATPIII criteria found low HDL cholesterol to be the
commonest component, though followed by abdominal (central) obesity. Similarly,
a significantly (p = 0.0001) larger proportion of female diabetics (57.1%)
had central obesity as compared to males (13.5%), a result that is consistent
with Al-Lawati et al. (2003). Moreover, it was found that hypertension
and low HDL cholesterol prevalence were markedly higher (p = 0.001; p
= 0.001) in female diabetics than males. This may explain the higher prevalence
of the metabolic syndrome in female diabetics as compared to males. Hypertriglyceridaemia
prevalence was comparable in both sexes. Low HDL cholesterol was the commonest
component of the metabolic syndrome in total diabetic patients in Ghana.
In comparison with type 1 and 2 diabetes, hypertension was the most frequent
in type 1 diabetes (Thorn et al., 2005) and dyslipidaemia the commonest
in type 2 diabetes (Isomaa et al., 2001), all by the NCEP ATPIII
criteria. Typically, the reduced HDL levels in plasma of patients with
type 2 diabetes are manifest as reductions in the HDL2b subspecies
and relative or absolute increases in smaller denser HDL3b
and HDL3C. It is well documented that reduced HDL cholesterol
levels are associated with an increased risk of coronary heart disease
(CHD) (Gordon et al., 1989).
A sizable number, 27.4% of the Ghanaian diabetes mellitus patients had
metabolic scores of five and four and hence carry higher risk for cardiovascular
disease. Another 28% of the diabetic patients had a metabolic score of
three, that is, they satisfy the minimum requirements of metabolic syndrome
and hence carry cardiovascular risk. Further, 43.9% had metabolic scores
of two and one and did not have metabolic syndrome. Nevertheless, the
management of diabetic patients with metabolic score of one and two should
focus on strategies for reduction of these minimal CVD risk factors. This
is because alone, each component of the cluster conveys increased CVD
risk, but as a combination, they become much more powerful (Kaplan, 1989).
A greater percentage of female diabetics (33.9%) had higher metabolic
scores than their male (12.7%) counterparts. Conversely, a smaller percentage
of female diabetics (33.6%) had lower metabolic scores than their male
(66.6%) counterparts. These translate to the fact that female diabetics
individually carry more metabolic syndrome factors and hence higher risk
for CVD than their male counterparts. This may be due to consumption of
high fat and energy dense diets and sedentary lifestyles (adverse physical
activity patterns) usually observed more in females than males in Ghana
and genetic factors.
In conclusion, more than half of the diabetic patients in Ghana had metabolic
syndrome. Low HDL cholesterol was the commonest component of metabolic
syndrome, followed by hypertension, among the studied population. In females,
central obesity was the commonest component of the syndrome, followed
by low HDL cholesterol. In males, hypertension was the commonest component,
followed by hypertriglyceridaemia. Metabolic syndrome, central obesity,
hypertension and low HDL cholesterol were more prevalent in females, while
prevalence of hypertriglyceridaemia was comparable in females and males.
Additionally, female diabetics individually carried more metabolic syndrome
factors than males and hence female diabetics were more prone to cardiovascular
disease than their male counterparts.
It is therefore, being recommended that in the management of diabetes
mellitus, risk factors of the metabolic syndrome should be assessed from
time to time and the appropriate treatment given. This will help to reduce,
if not prevent, CVD and cardiovascular mortality.
Our gratitude goes to Ghana Education Trust Fund (GETFUND), through the
University for Development Studies (UDS), Tamale, Ghana, for financial
support (GETFUND support to UDS, 2005).
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