CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 9, October 2012
516
AFRICA
obese participants, with no incidence of hypertension recorded
in the non-obese group (Table 4). Ibhazehiebo also found a
considerable increase (
p
-
value not reported) in the systolic
(
SBP) and diastolic blood pressure (DBP) of the obese subjects
following graded exercise. The increase heightened as the
intensity of the exercise progressed from mild to severe (Table
4).
By contrast, only modest increases were observed in the SBP
and DBP values of the non-obese subjects. When increases in BP
were compared in both groups following graded exercise, highly
significant increases in SBP were observed in the obese groups
(
p
<
0.01) (
Table 4).
Asfaw’s study displayed similar trends, suggesting a clear
relationship between obesity and four diagnosed chronic
diseases (arthritis, asthma, diabetes and heart diseases).
2
When
compared with non-obese subjects, each chronic disease was
more prevalent in the obese respondents (Table 5).
Discussion
We systematically reviewed the available literature in this
article to assess current evidence on obesity and its association
with increased co-morbidities among obese individuals on the
African continent. The results of this review demonstrate a
higher prevalence of obesity in urban populations compared
with their rural counterparts. Studies from both Amoah
33
and
Agyemang
et al
.
34
reported similar findings in their urban and
rural populations, however, it was intriguing to see Agyemang
et al
.
34
compare rural and urban Ghanaians with their Dutch
counterparts.
The large disparity found between Ghanaian residents in the
Netherlands and their urban/rural counterparts suggests that
environmental factors are implicated in the aetiology of obesity.
34
This provides new insights into the possible role of migration-
related factors on overweight and obesity in Western countries.
This further signals a great need to address overweight and
obesity among migrant populations living in Western countries.
It also provides an essential bedrock for further studies to
ascertain migration-related lifestyle changes and factors that lead
to overweight and obesity among these populations in Western
countries.
Studies reporting a higher prevalence of overweight and
obesity among urban residents are consistent with recent studies
in African countries;
6,38,39-41
however, the results from the studies
presented in this review seem to be at variance with most urban–
rural analyses of obesity in some developed countries.
42
For
instance, in the UK and USA, some studies reported a higher
proportion of obesity and overweight in the rural than the urban
population.
30,43
Higher prevalence of obesity was also found in
those with a lower income and least education in developed
countries,
44,45
contradicting the findings in this review that
associated obesity with affluence and literacy among African
populations.
Most observational studies conducted in industrialised
countries also suggested a positive association of obesity with
low-income and deprived neighbourhoods.
46-50
This obvious
contradiction has been suggested to be due to heightened
deprivation
42
and exposure to poor-quality foods, which are the
default choice due to low income
42
among the poor in Western
countries.
On the contrary, a possible explanation for the higher
prevalence of obesity in affluent and urban populations in Africa
may be explained by the increasing evolvement of urbanisation
TABLE 5. PREVALENCE OF CHRONIC DISEASEAMONG OBESEAND NON-OBESE INDIVIDUALS FROM
TWO DIFFERENT COUNTRIES
2
Author, country
Sample size
total
Doctor-diagnosed
chronic diseases
Obesity status
Senegal
South Africa
Asfaw
2
South Africa/Senegal
3 190
Arthritis
Non-obese
Obese
17.3 (15.4–19.2)
24.1 (15.8–32.3)
17.1 (14.1–20.0)
22.4 (16.9–27.1)
Asthma
Non-obese
Obese
4.2 (3.2–5.2)
10.0 (4.1–15.9)
5.4 (4.1–6.9)
7.6 (5.3–10.5)
Diabetes
Non-obese
Obese
1.6 (1.0–2.2)
2.9 (0.4–6.2)
5.4 (4.1–6.8)
7.6 (5.1–10.2)
Heart disease
Non-obese
Obese
7.8 (6.7–9.1)
13.7 (7.0–20.4)
13.3 (11.3–15.3)
19.4 (15.7–23.3)
Values are mean (95% confidence interval); significant differences were not clearly reported
TABLE 4. EFFECTS OF OBESITY ON BLOOD PRESSURE FOLLOWING GRADED EXERCISE IN OBESEAND NON-OBESE SUBJECTS
27
Author, country
Exercise Blood pressure changes following graded exercise
Sample size
Degree of exercise
SBP (mmHg)
obese
SBP (mmHg)
non-obese
DBP(mmHg)
obese
DBP (mmHg)
non-obese
Males Females
Ibhazehiebo
et al
.
36
Nigeria
60
60
Mild (M)
Mild (F)
Mild overall
156.3
±
14.0
141.0
±
9.0
a
150.4
±
10.3
b
135.0
±
7.4
134.5
±
10.5
94.3
±
8.6
87.9
±
10.0
86.4
±
10.1
84.5
±
8.6
70.1
±
7.4
74.6
±
4.2
78.3
±
9.4
Moderate (M)
Moderate (F)
Moderate overall
163.4
±
10
152.3
±
11.0
a
161.7
±
9.6
b
148.2
±
14.8
140.3
±
11.6
113.8
±
10.1
93.6
±
7.0
92.0
±
6.0
91.7
±
6.0
84.6
±
12.4
78.3
±
9.2
83.9
±
I7.5
Severe (M)
Severe (F)
Severe overall
173.1
±
14.0
163.1
±
9.0
a
169.4
±
11.2
b
153.0
±
13.1
148.8
±
11.8
126.0
±
10.8
98.5
±
10.0
95.4
±
10.0
97.4
±
8.9
89.2
±
11.5
85.8
±
10.9
89.3
±
9.2
SBP, systolic blood pressure; DBP, diastolic blood pressure (mmHg); M, males; F, females; mean
±
(
standard deviation)
a
p
< 0.05 between genders.
b
p
< 0.001 between obese and non-obese groups.
