Ethnic Variations in Risk Factor Profile

Archives of Medical Research 37 (2006) 655–662

ORIGINAL ARTICLE

Ethnic Variations in Risk Factor Profile, Pattern and
Recurrence of Non-Cardioembolic Ischemic Stroke
Dirk Deleu,a Ayman A. Hamad,a Saadat Kamram,a Abbas El Siddig,a
Hassan Al Hail,a and Samir M.K. Hamdyb
a

Departments of Neurology and bCardiology, Hamad Medical Corporation, Doha, State of Qatar

Received for publication September 28, 2005; accepted January 6, 2006 (ARCHMED-D-05-00398).

Background. Ischemic stroke is influenced by ethnic and geographical variations. The
aim of this study was to identify the risk factor profiles, subtypes and recurrence of
non-cardioembolic ischemic stroke for the two largest subpopulations, the Arab and
South Asians, at the only stroke-admitting hospital in Qatar.
Methods. Data on stroke patients admitted to Hamad Medical Corporation from January
through December 2001 were reviewed in January 2005. Only patients with non-cardioembolic ischemic stroke and complete work-up were included.
Results. A total of 303 patients with ischemic non-cardioembolic stroke fit the entry criteria. Sixty seven percent of the overall patient population (sex ratio 2:6, M/F) was of

Arab origin, and 32% were South Asians. Hypertension was the most commonly encountered risk factor followed by dyslipidemia, diabetes mellitus, and obesity. Significant differences between the Arab and South Asian subgroup of patients were observed with
respect to number of risk factors and occurrence of obesity and diabetes. Carotid artery
stenotic lesions, ventricular wall motion abnormalities and stroke recurrence were observed with a higher frequency in the Arab subgroup of patients compared with the South
Asians. The majority of strokes were lacunar hemispheric strokes (68%), followed by
lacunar brainstem strokes (15%) and large-vessel hemispheric infarctions (10%). Patients
with a previous history of stroke had a higher frequency of carotid artery stenosis ( p 5
0.05) and risk of stroke recurrence ( p 5 0.04).
Conclusions. Unlike in other studies originating from the Arabian Gulf, lacunar stroke is
the most common subtype of non-cardioembolic ischemic stroke in both the Arabs and
South Asians in Qatar. Significant ethnic differences in age of occurrence, risk factor profile,
and cardiovascular variables were observed. Ó 2006 IMSS. Published by Elsevier Inc.
Key Words: Ischemic stroke, Risk factor, Echocardiography, Ethnicity, Qatar, Arab, South Asian.

Introduction
Stroke, the third leading cause of death in developed countries, is a major cause of adult long-term neurological
disability and accounts for the greatest number of hospital
admissions related to neurological diseases (1). Stroke is
generally more prevalent in the fifth and sixth decade of

Address reprint requests to: Dirk Deleu, MD, PhD, FAAN, FRCP,

Department of Neurology Medicine, P.O. Box 3050, Hamad Medical
Corporation, Doha, State of Qatar; E-mail: doc_deleu@hotmail.com

life, and South Asians and people of African ancestry seem
to be more susceptible than their Caucasian counterparts
(2,3). Over the last decade a series of publications on the
epidemiology of stroke originating from the Arabian peninsula have reported a stroke incidence among the local
population on the order of 28273/100,000 inhabitants/year
(4–6). This low incidence rate probably relates to the relative young age of this population and appears to be much
lower compared with that encountered in Western countries
(150–200/100,000 people/year) (7). However, the dramatic
change in lifestyle in the Arabian Gulf countries over the
past few decades shows that stroke, in particular ischemic

0188-4409/06 $–see front matter. Copyright Ó 2006 IMSS. Published by Elsevier Inc.
doi: 10.1016/j.arcmed.2006.01.001

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Deleu et al./ Archives of Medical Research 37 (2006) 655–662

stroke, poses a major health threat because of its associated
morbidity and mortality, as well as its social and economic
impact. For instance, in 1997 in Qatar, stroke patients occupied 10% of hospital beds (6).
The State of Qatar is the peninsula bordering the Arabian Gulf and Saudi Arabia and has an estimated population size of 850,000. No official data are available, but it
is estimated that the expatriate population constitutes about
60% of the total population. Qatar is a member of the Eastern Mediterranean World Health Organization (WHO) and
free national health care service for all nationals is the cornerstone of the health care program. In addition, free medical service is provided for expatriates and visitors
examined at the Accident & Emergency Department, without requiring any referral from a health center. Hamad
Medical Corporation (HMC) is the largest single governmental hospital in the State of Qatar with a capacity of
1,600 beds. Thus far, there are no private hospitals admitting stroke patients.
To understand the mechanisms of stroke and to target
prevention, it is essential to recognize how risk factors differ among etiological subtypes of stroke and/or ethnic
groups. In addition, its prevention may critically reduce
the cumulative public health burden associated with it. Several retrospective hospital-based studies on stroke have
emerged from different Arabian Gulf countries (6,8–12).
However, none has focused on the most common subtype
of stroke, non-cardioembolic ischemic stroke. Furthermore,
no data from government agencies are available on non-cardioembolic ischemic stroke. The purpose of this hospitalbased study was to evaluate risk factor profile and the subtypes, as well as the rate of recurrence, of non-cardioembolic ischemic stroke in this Arabian Gulf state
community. More importantly, on the basis of this we investigated for potential ethnic variations in non-cardioembolic

ischemic stroke between the two largest subpopulations in
this country, Arabs and South Asians.

Patients and Methods
Setting
The data of all patients admitted from January 2001
through December 2001 with stroke [categories 430–438
of the International Classification of Diseases, 9th revision
(ICD–9)] at HMC—the only stroke-admitting facility in
Doha and the whole of Qatar—were analyzed. To allow
a sufficient long-term follow-up the review took place in
January 2005, providing for some patients a follow-up
period of at least 4 years. Only patients with noncardioembolic ischemic stroke, complete medical records
(history and physical examination) and work-up [including
brain CT scan or MRI, carotid Doppler sonography, and
transthoracic echocardiography (TTE) between 3 and 5
days of admission to HMC] were included in this study.

Hence, screening for these conditions was part of the
work-up. Repeat neuroimaging was performed within 2

weeks of admission if the initial brain CT scan or MRI
(and MR angiogram) was normal. When TTE was inconclusive (e.g., due to lack of cooperation of the patient, unclear imaging or high suspicion of cardioembolic source),
transesophageal echocardiography (TEE) was performed.
Diagnostic Definitions and Criteria
The WHO definition for stroke: ‘‘rapidly developing clinical symptoms and/or signs resulting in focal or global disturbance in cerebral function leading to death or persisting
for more than 24 h with no apparent cause other than vascular’’ was used (13). Non-cardioembolic ischemic stroke
was defined as a stroke resulting from any cause except cardiac embolism, hypercoagulopathy or hematological disorder. Hence, patients with transient ischemic attacks,
intracerebral or subarachnoidal hemorrhage, proven cardioembolic ischemic stroke and stroke caused by hypercoagulopathies or hematological disorders were excluded.
A patient was considered to be hypertensive with an established history of blood pressure (BP) O140/90 mmHg in
the non-acute phase or supervised use of antihypertensive
medication (14). Patients with transient increase in BP on
admission were not considered to be hypertensive. The criteria for diagnosing diabetes mellitus were the following:
past history of supervised diabetes control or consistently
high fasting plasma glucose levels (O7.0 mmol/L) (15).
Dyslipidemia was defined as fasting plasma total cholesterol levels O5.2 mmol/L, plasma triglyceride levels
O2.0 mmol/L, plasma HDL-cholesterol !0.9 mmol/L or
plasma LDL-cholesterol O3.4 mmol/L or using supervised
treatment of hypolipidemic medication (16). A body mass
index (BMI) $30 kg/m2 was taken as diagnostic criterion
for obesity. Smoking was classified into two categories:

(1) non-smokers/former smokers (never smoked regularly
or stopped regular smoking $5 years ago) and (2) smokers
(regular daily cigarette smoking within the last 5 years).
Because of inaccuracy of the medical records, we did
not quantify the amount of consumption or attempt to
differentiate among cigarette, cigar and shisha (waterpipe)
smoking.
A cerebral infarction was diagnosed when brain CT scan
showed a hypodense area corresponding to the clinical picture. Lacunar infarctions were diagnosed when brain CT
scan was repeatedly normal or revealed a small deep infarction (#2 cm in the longest diameter) in the territory of
a penetrating vessel and when the associated clinical presentation was suggestive of a lacunar syndrome. Stroke recurrence was defined as a new cerebrovascular event that
met one of the following criteria (17): (1) the event resulted
in a neurological deficit that was clearly different from that
of the index stroke in 2001 and (2) the event involved a
different anatomic site or vascular territory from that of

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Ethnic Variations in Non-Cardioembolic Stroke

the index stroke. All acute neurological events occurring
within 3 weeks from the onset of the index stroke were considered as part of the same event.
Data Collection
The following data were collected from all eligible patients’ case records: age, gender, nationality, ethnicity
(based on tribal name and area of origin), past or current
history of stroke, presence of stroke-preventive therapy before admission, presence of modifiable cardiovascular risk
factors (including hypertension, diabetes, cigarette smoking, dyslipidemia, obesity, oral contraceptives, coronary
artery disease, left ventricular dysfunction), complete
neurological, vascular and cardiac examination, TTE or
TEE with the determination of the left ventricular ejection
fraction, carotid Doppler sonography to determine the presence of stenotic lesions of the carotid arteries (50% stenosis
was considered significant), neuroimaging (brain CT or
MRI) with determination of subtype of ischemic stroke
(small- or large-vessel stroke), site of stroke (hemispheric
or brainstem) and, finally, in-hospital mortality due to
stroke. In addition, secondary stroke prevention therapy
and stroke recurrence after the index stroke in 2001 were
recorded. Cases of symptomatic stroke recurrence were
confirmed by readmission to HMC only.
Data Analysis

The data analysis is largely descriptive. All data were coded
using Statistical Package for Social Sciences (SPSS) for
Windows, version 10.0 data entry program. Data are expressed as mean 6 standard deviation (SD). Where appropriate, means of the different variables were compared
using Student’s t-test. Comparison of non-continuous variables between groups was performed by non-parametric
testing. Pearson’s correlation coefficient was used to determine the association between the left ventricular ejection
fraction and the number of vascular risk factors and
between smoking and carotid artery stenosis. Values of
p !0.05 were considered significant.

Results
Patient Population
From the 455 patients admitted with ischemic stroke
in 2001, 303 (67%) matched the inclusion criteria of this
study. Patients excluded had atrial fibrillation (61 patients),
proven left ventricular thrombus (18 patients), hemorrhagic
infarction or hemorrhagic conversion of the ischemic stroke
(40 patients), hypercoagulopathy (6 patients), whereas in 27
patients data were missing or incomplete.
In our study population, the number of Qatari and nonQatari was almost comparable (48.5 vs. 51.5%). Further-

more, 67% of the overall patient population was of Arab origin (Arab expatriates and Qataris), whereas 32% were
South Asians. The overall sex ratio was 2:6 (M/F). Demographic characteristics of the study population are summarized in Table 1. The age was significantly higher in the
Qatari patients compared to the expatriate patients (67.3
vs. 55.5 years, p 5 0.0001). The age distribution of the patient population according to gender is shown in Figure 1.
In addition, the male:female ratio was significantly lower
in the Qatari patients (1:46) and Arab patient population
(1:83) in general, compared with the South Asian patients
(9:78, p 5 0.0001).
The clinical characteristics of the Arab and South Asian
subgroup of patients are summarized in Table 2.
Risk Factors for Non-Cardioembolic Ischemic Stroke
in this Community
Table 3 summarizes the patients’ modifiable cardiovascular
risk factor profile: overall hypertension was the most commonly encountered risk factor followed by dyslipidemia,
diabetes mellitus, and obesity. More than 25% of patients
were smokers, and a history of coronary artery disease
including myocardial infarction was observed in 23% of
patients. Eight percent of patients had no risk factor at
all, whereas 12% had one risk factor, predominantly arterial
hypertension. In the group of patients with at least two risk

factors, dyslipidemia (particularly hypercholesterolemia)
was most prevalent. One third of patients had three
vascular risk factors, most commonly a combination of
diabetes, hypertension and dyslipidemia (particularly
hypercholesterolemia). Almost one quarter of the study
Table 1. Demographic characteristics of patients with
non-cardioembolic ischemic stroke (n 5 303)
Variable
Age
Male
Female
Total
Gender
Male
Female
Ethnicity
Arab
South Asian
Other
Nationality

Qatari
Indian
Pakistani
Bengali
Palestinian
Jordanian
Egyptian
Other
SD, standard deviation.

Frequency (%) or mean 6 SD (range)
60.0 6 12.2 (24–94)
64.3 6 11.4 (25–83)
61.2 6 12.1 (24–94)
220 (72)
83 (28)
202 (67)
97 (32)
4 (1)
147
50
21
14
14
11
10
36

(48.5)
(16.5)
(6.9)
(4.6)
(4.6)
(3.6)
(3.3)
(11.9)

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Deleu et al./ Archives of Medical Research 37 (2006) 655–662
80
Male
70

Female

60

Number

50
40
30
20
10
0
≤30

31-39

40-49

50-59

60-69

70-79

80-89

above 90

Age category (years)
Figure 1. Age and sex distribution.

population had had a previous stroke, with 27% receiving
aspirin either for secondary stroke prevention or cardiovascular reasons.
The prevalence of major risk factors across sexes was
only significant for diabetes mellitus (76% in females vs.
51% in males, p 5 0.0001). In addition, Qatari patients
had a significant higher prevalence of diabetes mellitus
compared to expatriates (67 vs. 49%, p 5 0.003). Significant differences between the Arab and South Asian
subgroup of patients were observed with respect to number
of risk factors and occurrence of obesity (BMI) and diabetes (Table 2). Although there was a trend of a higher
frequency of smokers in the South Asian community,
the difference was not statistically significant ( p 5 0.09).
Echocardiographic and Carotid Sonographic Parameters
Overall, the ejection fraction averaged 59.3% (Table 3).
Over one quarter of the patients had ventricular wall motion
abnormalities (hypokinetic, dyskinetic or akinetic ventricular wall segments). In patients with and without ventricular
wall motion abnormalities the mean ejection fraction was
49.6 6 12.5% and 62.8 6 6.3% ( p 5 0.0001), respectively.
The presence of ventricular wall motion abnormalities
highly correlated ( p 5 0.001) with the number of vascular
risk factors (3.2 in patients with ventricular wall motion abnormalities vs. 2.7 in the group of patients without ventricular wall motion abnormalities). Ventricular wall motion
abnormalities were not a predisposing factor for stroke
recurrence.
Almost 15% of patients had significant stenotic lesions
on the carotid arteries. In this study population there was
no significant association between smoking and carotid artery stenosis, but this may be related to the small number of
patients in the subpopulations. Carotid artery stenotic

lesions, cardiac wall motion abnormalities and stroke recurrence were observed with a higher frequency in the Arab
subgroup of patients compared with the South Asians
(Table 2).
Table 2. Clinical characteristics, distribution of risk factors
and ischemic stroke subtype among patients of Arab and
South Asian origin (n 5 299)

Variable
Age (years)
Male
Female
Total
Gender ratio
Male/female
BMI (kg/m2)
Number of risk factors
Vascular risk factor
Hypertension
Diabetes
Dyslipidemia
Obesity
Previous stroke
Smoking
CAD
EF (%)
Ventricular wall motion
abnormalities
Carotid artery stenotic
lesions

Arab population
(n 5 202)

South Asian population
(n 5 97)

Mean 6 SD or
frequency (%)

Mean 6 SD or
frequency (%)

65.0 6 10.8
66.0 6 10.9
65.4 6 10.7

52.6 6 10.3*
54.0 6 11.1**
52.7 6 10.3*

1:83
32.7 6 11.1
3.00 6 1.2

9:78*
27.7 6 10.8**
2.59 6 1.4{

151 (74.7)
130 (64.3)
120 (59.4)
72 (35.6)
54 (26.7)
46 (22.8)
43 (21.3)
58.5 6 10.3
60 (29.7)

72 (74.2)
45 (46.4)x
48 (49.5)
19 (19.6)y
20 (20.6)
31 (31.9)
17 (17.5)
60.9 6 10.1
19 (19.6)*

34 (16.8)

19 (6.2)

xx

BMI, body mass index; CAD, coronary artery disease; EF, ejection fraction; LVD, left ventricular dysfunction; SD, standard deviation.
*p 5 0.0001; **p 5 0.002; {p 5 0.005; xp 5 0.004; yp 5 0.006; xxp 5
0.014.

Ethnic Variations in Non-Cardioembolic Stroke
Table 3. Identifiable vascular risk factors, echocardiographic
parameters, carotid Doppler sonographic findings and ischemic
stroke subtype (n 5 303)
Variable

Frequency (%) or mean 6 SD (range)

Vascular risk factor
Hypertension
209 (69)
Dyslipidemia
173 (57)
Diabetes
154 (51)
Obesity
90 (30)
Smoking
79 (26)
Previous stroke
73 (24)
Coronary artery disease
69 (23)
Left ventricular dysfunction
14 (5)
None
24 (8)
Body mass index (kg/m2)
31.0 6 11.3 (13.7–89.3)
Number of vascular risk factors
2.8 6 1.2 (0–7)
Prior anti-stroke therapy
ASA (or combination therapy)
82 (27)
None
221 (73)
Ejection fraction (%)
59.3 6 10.2 (18–76) (median 62)
Ventricular wall motion
abnormalities
No
224 (74)
Yes
79 (26)
Carotid artery stenotic lesions
No
260 (86)
Yes
43 (14)
Stroke subtype
Hemispheric lacunar
206 (68.0)
Hemispheric non-lacunar
31 (10.2)
Brainstem lacunar
44 (14.5)
Brainstem non-lacunar
9 (3.0)
Combination lacunar
12 (4.0)
Combination non-lacunar/lacunar
1 (0.3)
Stroke in-hospital mortality
16 (5.3)
Follow-up
None
72 (23.7)
!1/2 year
22 (7.3)
1/222 year
20 (6.6)
O2–4 year
189 (62.4)
Stroke recurrence
Unknown
72 (23.7)
No
202 (66.7)
Yes
29 (9.6)
ASA, acetylsalicylic acid; SD, standard deviation.

Ischemic Stroke Characteristics
With regard to the location of the infarct, the anterior circulation was affected in 78% and the posterior circulation in
17% of patients, whereas both territories were affected in
5% of cases. The majority of non-cardioembolic ischemic
strokes were small-vessel infarctions resulting in lacunar
hemispheric strokes in 68%, followed by lacunar brainstem
strokes in almost 15% of patients. Large-vessel hemispheric
infarctions were observed in 10% of patients. The direct
stroke-related mortality 1 month following the non-cardioembolic ischemic stroke was 5% and was exclusively associated with large-vessel stroke. The ratio for mortality was
consequently higher for males than females (65 vs. 35%).

659

With regard to the risk factors, there was no relationship
between each of the risk factors and the ischemic stroke
subtype. Furthermore, with regard to stroke subtype, no
difference was observed between both subpopulations.
Secondary Stroke Prevention and Stroke Recurrence
Over 25% of patients had been treated with antiplatelet
drugs, predominantly aspirin, prior to their index stroke.
The number of patients lost to follow-up after their index
stroke in 2001 (primarily expatriates returning to their
country of origin) was 24%. The median follow-up of the
study population was between O2 and 4 years (Table 3).
In the 189 patients with long-term follow-up after the index
stroke in 2001, the stroke recurrence rate was almost 10%.
Patients with a previous history of stroke had a higher frequency of carotid artery stenosis ( p 5 0.05) and risk of
stroke recurrence ( p 5 0.04). With relation to frequency
of stroke recurrence, no difference was observed between
both subpopulations.

Discussion
Consistent with other studies in the region (9–11,18), our
findings indicate that non-cardioembolic ischemic stroke
is most prevalent between the ages of 55–75 years with
a male preponderance, both in the Arab and South Asian
subgroup of patients.
As for most studies originating from the Arab Gulf
countries (4,5,8) and as observed in our study as well, the
gender ratio is largely in favor of males and reflects the demographic structure in Qatar with its large expatriate male
work force. Male preponderance seems to be a phenomenon
observed in most epidemiological studies related to vascular events in the Middle East. For instance, a recent epidemiological study assessing risk of acute myocardial
infarction in different areas of the world found the highest
male:female ratios in the Middle East and South Asia, 6.2
and 5.8, respectively, compared with values around 2.4 in
Western populations (19). The same study provides interesting data with regard to age of a vascular event. The Arab
and South Asian population have myocardial infarction
around the age of 52 years, being 10 years earlier than Caucasians (19). Our study revealed that the South Asian subgroup of patients had stroke at approximately the same age
as the age reported for myocardial infarction. However, our
Arab subgroup of patients had stroke at a much older age
(65 years). Whether this demonstrates differential predisposition of cerebral and coronary vascular structure across
populations to develop atherosclerosis is unclear but definitely needs further exploration. Furthermore, it should be
emphasized that other factors besides ethnic factors, such
as sociocultural and economic factors, may have contributed to this difference.

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Deleu et al./ Archives of Medical Research 37 (2006) 655–662

Hypertension, diabetes mellitus, dyslipidemia, smoking
and coronary heart disease are well-known risk factors for
stroke and are found in up to 80% of patients with ischemic
stroke. (20) Diabetes mellitus proved to be a strong determinant for coronary artery disease and ischemic stroke among
middle-aged women. (21) The prevalence of hypertension
and diabetes mellitus in stroke populations in industrialized
countries and certain Arabian Gulf countries (e.g., Saudi
Arabia and Kuwait) is |54–72% and 14–69%, respectively
(5,8,9,1,22–24). Hypertension and diabetes mellitus were
much more commonly observed in our patient population
(69% and 51%, respectively) than in Western studies.
Over the last 4 years, changes in the pattern of risk factors have emerged. An epidemiological study on stroke in
Qatar in 1997 (6) revealed that hypertension (66%) was
the most common risk factor, followed by diabetes mellitus
(46%). Although these epidemiological studies focused on
stroke in general, comparison is still valid because ischemic
stroke constituted the majority of cases (80%). In our overall patient population, dyslipidemia has surpassed diabetes
mellitus and has become the second most important modifiable vascular risk factor in ischemic stroke. However, different potentially modifiable vascular risk factor profiles
were identified for the two ethnic subgroups of patients.
Whereas dyslipidemia was the second most important risk
factor in the South Asian subgroup of stroke patients, in
the Arab subgroup of patients diabetes mellitus remained
the second most important risk factor, and this largely because of the significant contribution of native Qatari patients, particularly female. Diabetes mellitus is prevalent
among Qataris and Arabs in the Middle East with prevalence rates varying between 15.0 and 23.7% (6,22,25). Environmental and sociocultural factors such as changes in
lifestyle (sedentary, stress, fast food) in this rapidly developing part of the world and consanguineous marriages
may account for these findings. Similarly, the prevalence
of diabetes mellitus in the South Asian population is also
high, varying between 11 and 24% (26,27). The prevalence
(around 25%) of coronary artery disease was similar to that
reported in other studies (9,18,22). Cigarette smoking in
a dose-related manner is a known risk factor for coronary
artery disease and stroke, especially ischemic stroke (28).
In our study, smoking accounted for 2% of all non-cardioembolic strokes, a figure comparable with that of other recent studies in the region (22,29).
Some studies found an increasing risk of stroke, particularly ischemic stroke, with a 6% increase in adjusted relative risk for each unit increase in BMI (30,31). This was
subsequently confirmed by Song et al., who showed a linear
relationship between ischemic stroke and BMI (32). Compared with the BMI average in their study, the overall
BMI average of our patient population was O30. This
was particularly attributed to the Arab subgroup of patients
(including Qataris), who had a significantly higher BMI
than the South Asian subgroup of patients.

With reference to stroke subtype, our proportion of lacunar infarctions (68%) was higher than that in Western
stroke studies, ranging from 10 to 24% (23,33,34). Previous
stroke studies in Arabian Gulf countries revealed conflicting results. Large-vessel non-cardioembolic infarction was
the most common type of stroke in hospital-based studies
originating from Kuwait (4) and Saudi Arabia (11,29). Ischemic stroke studies from South Asia revealed mixed results: a Pakistani study showed a preponderance of
lacunar strokes (43 vs. 27% large-vessel infarcts) (35),
whereas an Indian study revealed a majority of large-vessel
infarcts (41 vs. 18% lacunar infarcts) (36). In both studies
the frequency of cardioembolic strokes was comparable.
Although the association between small-vessel ischemic
stroke and hypertension and diabetes mellitus has recently
been challenged (37), it is widely believed that hypertension constitutes a risk factor for large- and small-vessel disease, whereas diabetes mellitus is mainly associated with
arteriolopathy, probably explaining the high frequency of
lacunar infarctions in our patients. Yip et al. showed that serum levels of cholesterol did not differ between various
subtypes of ischemic strokes (38). Contrary to that finding
(38), patients with large-vessel infarcts did not have more
vascular risk factors than those with lacunar stroke.
Doppler sonographic findings corresponded well with
those reported in a Saudi Arabian study, which had similar
rates of significant carotid artery stenosis, associated
however with a lower rate of lacunar infarctions (11).
Admittedly, their patients included all strokes subtypes
(including intracranial hemorrhage).
There is a wide variation among stroke recurrence rates
in study populations. These differences may be related to
hospital vs. community-based samples, study designs and
qualifying criteria for a recurrent event (39–41). In our
study, the stroke recurrence rate corresponded well with
that reported in other long-term follow-up studies (40,42).
Furthermore, data from a recent Japanese study indicate
that a previous history of stroke predicts stroke recurrence
for all subtypes of ischemic stroke, whereas diabetes mellitus appears to be a predictor of recurrence for patients with
lacunar infarcts (43). Our study was not designed and did
not have the power to evaluate the potential role of diabetes
mellitus in recurrence of lacunar infarction.
Few studies report on echocardiographic findings in patients with non-cardioembolic ischemic stroke. Although
comparison is often difficult among the different studies
and patient groups, in one Japanese study on patients with
non-rheumatic atrial fibrillation, the left ventricular ejection
fraction was significantly lower in patients with cerebral infarction than in those without cerebral infarction (62 vs.
73%) and congestive heart failure was significantly more
frequent in patients with cerebral infarction than in those
without cerebral infarction (40% vs. 14%) (44). In our patient population, there was a good correlation between the
ejection fraction and the number of vascular risk factors.

Ethnic Variations in Non-Cardioembolic Stroke

Furthermore, the ejection fraction was substantially lower in
our patients compared with that in the Japanese study, taking
into account the fact that our patients did not have atrial
fibrillation. Overall, we did not observe a higher frequency
of stroke recurrence in patients with ventricular wall motion
abnormalities. The reason for this might be that our patients
had no ventricular thrombus and/or atrial fibrillation, which
are known risk factors for ischemic stroke. The frequency of
patients with ventricular wall motion abnormalities was significantly higher in the Arab subgroup of patients compared
with South Asians and was most likely related to the significantly higher number of risk factors (3.00 vs. 2.59).
In-hospital mortality rates in non-cardioembolic stroke
are lower than that in cardioembolic stroke or intracerebral
hemorrhage (45). Compared to a 12% mortality rate for ischemic stroke reported in Qatar in 1997 (6), the in-hospital
case-fatality rate in our patient population was 6% and was
in accordance with that reported in other studies
(5,6,35,40,45–49). Improvements in stroke care probably
account for this reduction.
The limitations of this study may include its retrospective nature making determination of etiology (cardioembolic vs. non-cardioembolic stroke) sometimes more
difficult and the imbalance in number of patients between
both subpopulations. In addition, the non-systematic use
of transesophageal echocardiography and conventional angiography may have led to underestimation of angiopathies
and cardiac abnormalities. It is important to highlight that
the differences found are applicable to ethnic differences
found in this community and cannot be extrapolated. Reasons for this include potential sociocultural and economic
differences between the Arab and South Asian population.
The results with regard to stroke recurrence need to be interpreted with caution, particularly because of high lost to
follow-up of the expatriate patients. Finally, although it is
realized that the data from patients with incomplete or
missing information could have influenced our findings,
this was very unlikely because they accounted for !6%
of potentially eligible patients.
In conclusion, in both ethnic groups the triad of hypertension, diabetes and dyslipidemia are the most common risk
factors for non-cardioembolic ischemic stroke. A previous
history of stroke was a determined factor for stroke recurrence in our patient population. Furthermore, our results indicate that the overall distribution of non-cardioembolic
ischemic stroke types in Qatar differ substantially from that
of the Western and Southeast Asian populations and even
from that of other Arab Gulf countries. High frequency of
small-vessel disease, i.e., lacunar infarcts, and the high prevalence of diabetes mellitus as a risk factor are quite distinctive. Diabetes, obesity, carotid artery stenosis and coronary
artery disease with ventricular wall motion abnormalities
were found significantly more in the Arab subgroup of patients. However, this did not result in a difference in subtype
of ischemic stroke between both ethnic groups.

661

References
1. Bonita R, Beaglehole R, Asplund K. The worldwide problem of
stroke. Curr Opin Neurol 1994;7:5–10.
2. Cappuccio FP. Ethnicity and cardiovascular risk: variations in people
of African ancestry and South Asian origin. J Hum Hypertens 1997;
11:571–576.
3. Sacco RL, Kargman DE, Gu Q, Zamanillo MC. Race-ethnicity and
determinants of intracranial atherosclerotic cerebral infarction. The
Northern Manhattan Stroke Study. Stroke 1995;26:14–20.
4. Abdul-Ghaffar NU, el-Sonbaty MR, el-Din Abdul-Baky MS,
Marafie AA, al-Said AM. Stroke in Kuwait: a three-year prospective
study. Neuroepidemiology 1997;16:40–47.
5. al-Rajeh S, Larbi EB, Bademosi O, Awada A, Yousef A, al-Freihi H,
et al. Stroke register: experience from the eastern province of Saudi
Arabia. Cerebrovasc Dis 1998;8:86–89.
6. Hamad A, Hamad AA, Sokrab TO, Momeni S, Mesrauoa B,
Lingren A. Stroke in Qatar: a one-year, hospital-based study. J Stroke
Cerebrovasc Dis 2001;10:236–241.
7. Sudlow CL, Warlow CP. Comparing stroke incidence worldwide: what
makes studies comparable? Stroke 1996;27:550–558.
8. Qari FA. Profile of stroke in a teaching university hospital in the Western region. Saudi Med J 2000;21:1030–1033.
9. Al Rajeh S, Awada A, Niazi G, Larbi E. Stroke in a Saudi Arabian
National Guard community. Analysis of 500 consecutive cases from
a population-based hospital. Stroke 1993;24:1635–1639.
10. al-Rajeh S, Larbi E, Bademosi O, Awada A, Ismail H, al-Freihi H.
Pattern and ethnic variations in stroke in Saudi Arabia. J Neurol Sci
1991;102:112–118.
11. Awada A, al Rajeh S. The Saudi Stroke Data Bank. Analysis of the
first 1000 cases. Acta Neurol Scand 1999;100:265–269.
12. Al Jishi A, Pochiaratu K, Mohan PK. Profile of stroke in Bahrain.
Saudi Med J 1999;20:958–962.
13. World Health Organization. Cerebrovascular diseases: prevention,
treatment, and rehabilitation: report of a WHO meeting. World Health
Organ Tech Rep Ser No 469, 1971.
14. MacMahon S, Rodgers A. The epidemiological association between
blood pressure and stroke: implications for primary and secondary
prevention. Hypertens Res 1994;17(suppl 1):S23–32.
15. Anon. Report of the Expert Committee on the diagnosis and classification of diabetes mellitus. Diabetes Care 2000;25(suppl 1):S5–20.
16. Expert Panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults. Executive Summary of The Third Report of The
National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol In
Adults (Adult Treatment Panel III). JAMA 2001;285:2486–2497.
17. Hier DB, Foulkes MA, Swiontoniowski M, Sacco RL, Gorelick PB,
Mohr JP, et al. Stroke recurrence within 2 years after ischemic infarction. Stroke 1991;22:155–161.
18. al-Rajeh S, Larbi E, Bademosi O, Awada A, Ismail H, al-Freihi H,
et al. Stroke in a tertiary hospital in Saudi Arabia: a study of 372 cases.
Eur Neurol 1991;31:251–256.
19. Yusuf S, Hawken S, Ounpuu S, Dans T, Avezum A, Lanas F, et al.
Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control
study. Lancet 2004;364:937–952.
20. Sandercock PA, Warlow CP, Jones LN, Starkey IR. Predisposing factors for cerebral infarction: the Oxfordshire community stroke project.
BMJ 1989;298:75–80.
21. Manson JE, Colditz GA, Stampfer MJ, Willett WC, Krolewski AS,
Rosner B, et al. A prospective study of maturity-onset diabetes mellitus and risk factors of coronary heart disease and stroke in women.
Arch Intern Med 1991;151:1141–1147.
22. Al-Shammri S, Shahid Z, Ghali A, Mehndiratta MM, Swaminathan TR,
Chadha G, et al. Risk factors, subtypes and outcome of ischaemic stroke
in Kuwait—a hospital-based study. Med Princ Pract 2003;12:218–223.

662

Deleu et al./ Archives of Medical Research 37 (2006) 655–662

23. Bogousslavsky J, Van Melle G, Regli F. The Lausanne Stroke Registry: analysis of 1,000 consecutive patients with first stroke. Stroke
1988;19:1083–1092.
24. Jorgensen H, Nakayama H, Raaschou HO, Olsen TS. Stroke in patients with diabetes. The Copenhagen Stroke Study. Stroke 1994;25:
1977–1984.
25. Al-Nozha MM, Al-Maatouq MA, Al-Mazrou YY, Al-Harthi SS,
Arafah MR, Khalil MZ, et al. Diabetes mellitus in Saudi Arabia. Saudi
Med J 2004;25:1603–1610.
26. Shera AS, Rafique G, Khwaja IA, Baqai S, Khan IA, King H. Pakistan
National Diabetes Survey prevalence of glucose intolerance and associated factors in North West at Frontier Province (NWFP) of Pakistan.
J Pak Med Assoc 1999;49:206–211.
27. Reddy NK, Kumar DN, Rayudu NV, Sastry BK, Raju BS. Prevalence
of risk factors for coronary atherosclerosis in a cross-sectional population of Andhra Pradesh. Indian Heart J 2002;54:697–701.
28. Ueshima H, Choudhury SR, Okayama A, Hayakawa T, Kita Y,
Kadowaki T, et al. Cigarette smoking as a risk factor for stroke death
in Japan: NIPPON DATA80. Stroke 2004;35:1836–1841.
29. El Sayed MM, Adeuja AO, El-Nahrawy E, Olaish MA. Characteristics
of stroke in Hofuf, Saudi Arabia. Ann Saudi Med 1999;19:27–31.
30. Jood K, Jern C, Wilhelmsen L, Rosengren A. Body mass index in midlife is associated with a first stroke in men: a prospective population
study over 28 years. Stroke 2004;35:2764–2769.
31. Kurth T, Gaziano JM, Berger K, Kase CS, Rexrode KM, Cook NR,
et al. Body mass index and the risk of stroke in men. Arch Intern
Med 2002;162:2557–2562.
32. Song YM, Sung J, Davey Smith G, Ebrahim S. Body mass index and
ischemic and hemorrhagic stroke: a prospective study in Korean men.
Stroke 2004;35:831–836.
33. Lemesle M, Milan C, Faivre J, Moreau T, Giroud M, Dumas R.
Incidence trends of ischemic stroke and transient ischemic attacks in
a well-defined French population from 1985 through 1994. Stroke
1999;30:371–377.
34. Mohr JP, Caplan LR, Melski JW, Goldstein RJ, Duncan GW,
Kistler JP, et al. The Harvard Cooperative Stroke Registry: a prospective registry. Neurology 1978;28:754–762.
35. Syed NA, Khealani BA, Ali S, Hasan A, Akhtar N, Brohi H, et al.
Ischemic stroke subtypes in Pakistan: the Aga Khan University Stroke
Data Bank. J Pak Med Assoc 2003;53:584–588.
36. Kaul S, Sunitha P, Suvarna A, Meena AK, Uma M, Reddy JM.
Subtypes of ischemic stroke in a metropolitan city of South India
(one year data from a hospital based stroke registry). Neurol India
2002;(suppl 50):S8–14.

37. Schulz UG, Rothwell PM. Differences in vascular risk factors between
etiological subtypes of ischemic stroke: importance of populationbased studies. Stroke 2003;34:2050–2059.
38. Yip PK, Jeng JS, Lee TK, Chang YC, Huang ZS, Ng SK, et al.
Subtypes of ischemic stroke. A hospital-based stroke registry in
Taiwan (SCAN-IV). Stroke 1997;28:2507–2512.
39. Petty GW, Brown RD Jr, Whisnant JP, Sicks JD, O’Fallon WM,
Wiebers DO. Survival and recurrence after first cerebral infarction:
a population-based study in Rochester, Minnesota, 1975 through
1989. Neurology 1998;50:208–216.
40. Sacco RL, Shi T, Zamanillo MC, Kargman DE. Predictors of mortality
and recurrence after hospitalized cerebral infarction in an urban community: the Northern Manhattan Stroke Study. Neurology 1994;44:
626–634.
41. Burn J, Dennis M, Bamford J, Sandercock P, Wade D, Warlow C.
Long-term risk of recurrent stroke after a first-ever stroke. The
Oxfordshire Community Stroke Project. Stroke 1994;25:333–337.
42. Moroney JT, Bagiella E, Paik MC, Sacco RL, Desmond DW. Risk
factors for early recurrence after ischemic stroke: the role of stroke
syndrome and subtype. Stroke 1998;29:2118–2124.
43. Soda T, Nakayasu H, Maeda M, Kusumi M, Kowa H, Awaki E, et al.
Stroke recurrence within the first year following cerebral infarction—
Tottori University Lacunar Infarction Prognosis Study (TULIPS). Acta
Neurol Scand 2004;110:343–349.
44. Naito S, Imataka K, Seko Y, Fujii J. The predictive factors for cerebral
infarction in patients with non-rheumatic atrial fibrillation. J Cardiol
1990;20:385–391.
45. Fang J, Foo SH, Jeng JS, Yip PK, Alderman MH. Clinical characteristics of stroke among Chinese in New York City. Ethn Dis 2004;14:
378–383.
46. Ward G, Jamrozik K, Stewart-Wynne W. Incidence and outcome of cerebrovascular disease in Perth, Western Australia. Stroke 1988;19:
1501–1506.
47. Sacco SE, Whisnant JP, Broderick JP, Philips SJ, O’Fallon WM. Epidemiological characteristics of lacunar infarcts in a population. Stroke
1991;22:1236–1241.
48. Ashok PP, Radhakrishnan K, Sridharan R, el-Mangoush MA. Incidence and pattern of cerebrovascular diseases in Benghazi, Libya.
J Neurol Neurosurg Psychiatry 1986;49:519–523.
49. Kolominsky-Rabas PL, Sarti C, Heuschmann PU, Graf C,
Siemonsen S, Neundoerfer B, et al. A prospective community-based
study of stroke in Germany—the Erlangen Stroke Project (ESPro):
incidence and case fatality at 1, 3, and 12 months. Stroke 1998;29:
2501–2506.