Cardiovascular Journal of Africa: Vol 24 No 2 (March 2013)

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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 2, March 2013 AFRICA 17
Low prevalence of abdominal aortic aneurysm in the
Seychelles population aged 50 to 65 years
PATRICK YERLY, GEORGE MADELEINE, WALTER RIESEN, PASCAL BOVET
Abstract
The prevalence of abdominal aortic aneurysm (AAA) and its
risk factors are well known inWestern countries but few data
are available from low- and middle-income countries.We are
not aware of systematically collected population-based data
onAAA in theAfrican region.We evaluated the prevalence of
AAA in a population-based cardiovascular survey conducted
in the Republic of Seychelles in 2004 (Indian Ocean, African
region). Among the 353 participants aged 50 to 64 years and
screened with ultrasound, the prevalence of AAA was 0.3%
(95% CI: 0–0.9) and the prevalence of ectatic dilatations
of the abdominal aorta was 1.5% (95% CI: 0.2–2.8). The
prevalence of AAA in the general population seemed lower
in Seychelles than inWestern countries, despite a high preva-
lence in Seychelles of risk factors of AAA, such as smoking
(in men), high blood pressure and hypercholesterolaemia.
Keywords: abdominal aortic aneurysm, screening, ultrasonogra-
phy, population-based study, African region
Submitted 22/3/12, accepted 8/10/12
Published online 13/11/12
Cardiovasc J Afr 2013; 24: 17–18
DOI: 10.5830/CVJA-2012-070
Recent clinical trials have demonstrated a reduction in
mortality related to abdominal aortic aneurysm (AAA) in men
systematically screened with ultrasound at age 65 to 74 years.1-4
Risk factors of AAA include male gender, age and smoking, and
to a lesser extent hypertension, hypercholesterolaemia and overt
atherosclerosis.5,6 The US Preventive Services task force has
recommended the screening of AAA in men aged 65 to 75 years
who have ever smoked.7
In view of the limited population-based data onAAA available
in low- and middle-income countries,8,9 and none that we are
aware of in the African region, we examined the prevalence of
AAA in a population-based survey of cardiovascular risk factors
conducted in the Republic of Seychelles in 2004. Seychelles is
a rapidly developing middle-income island state located in the
Indian Ocean approximately 1 800 km east of Kenya (African
region).
In 2004, 42.8% of the population was aged less than 25
years and 9.7% was 50 to 64 years old. The majority of the
inhabitants is of African descent and a high prevalence of several
cardiovascular risk factors was previously demonstrated in the
population, particularly high blood pressure.10,11
Methods
A random age- and gender-stratified sample of all inhabitants
aged 25 to 64 years was drawn using computerised data of a
national census carried out in 2002 and thereafter regularly
updated by civil status authorities. Methods of the survey have
been described previously.12
From a total of 1 456 eligible participants (participation rate
80.2%), 566 were aged 50 to 64 years, and 474 took part in
the survey (participation rate 83.7%). We restricted the AAA
screening to this age range because AAA is rare at younger
ages.13,14
Ultrasound (General Electric LogiqBook connected to a
2–5-MHz transducer, General Electric Health Care, United
Kingdom) was performed in the 353 consecutive individuals
who took part in the survey during a 17-week period when a
sonographer was available. The abdominal aorta was scanned
from its most proximal visualisable segment to the iliac
bifurcation, both transversally and longitudinally. Its antero–
posterior and transverse diameters were measured at their
maximal sizes, and the larger of the two values was recorded.
Results
None of the screened subjects had a history of AAA. The
maximal diameter of the aorta could be well visualised in 329 of
the 351 eligible participants. AAA, defined as a diameter ≥ 30
mm, was found in only one man (diameter 31 mm, age 59 years,
never-smoker, obese, cholesterol 6.7 mmol/l, hypertensive,
diabetic). An ectatic dilatation of the aorta (diameter 25–29
mm), which can be regarded as precursor of AAA,15 was found
in four additional participants: three men and one woman (age:
52, 59, 62 and 63; two ex-smokers; all overweight; three with
hypertension; two with diabetes; total cholesterol: 5.0, 6.0, 6.3
and 7.4 mmol/l, respectively).
The prevalence of aneurysm or ectasy of the abdominal aorta
of all participants aged 50 to 64 years is shown in Table 1. In the
same age category, the prevalence was 15% for current smokers
(28% in men, 3% in women), 22% for ex-smokers (32% in men
and 3% in women), 70% for overweight participants (body mass
index ≥ 25 kg/m 2), 33% for obesity (≥ 30 kg/m2), 70% for high
blood pressure (≥ 140/90 mmHg or treatment), 27% for diabetes
mellitus and 63% for elevated total cholesterol levels (≥ 5.2
mmol/l).
Department of Internal Medicine, Division of Cardiology,
Lausanne University Hospital (CHUV), Lausanne, Switzerland
PATRICK YERLY, MD,
Unit for Prevention and Control of Cardiovascular Disease,
Ministry of Health, Victoria, Seychelles
GEORGE MADELEINE
Institute of Clinical Chemistry and Haematology, Canton
Hospital, St Gallen, Switzerland
WALTER RIESEN, MD
Institute of Social and Preventive Medicine (IUMSP),
Lausanne University Hospital, Lausanne, Switzerland
PASCAL BOVET, MD