CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
AFRICA
373
readings. Blood pressure measurements were performed twice,
5 min apart. Subjects were seated upright and relaxed with the
arm supported at heart level and measurements were taken using
the brachial artery.
Blood glucose level was measured using Vitros DT6011
Chemistry Analyser, an Ortho-Clinical Diagnostics tool
(Rochester, New York, USA). Quantitative determination of
total cholesterol (TC), high-density lipoprotein cholesterol
(HDL-C), C-reactive protein and triglyceride (TG) levels were
done by sequential multiple analyser computer (SMAC) using
the Konelab20i
TM
auto-analyser. Plasma fibrinogen level was
measured using a modified Clauss method (Multi fibrin U-test,
Dade Behring, Deerfield Illinois, USA) on the Dade Behring
BCS coagulation analyser.
Statistical analysis
The SPSS package (version 17.0, SPSS Inc) was used to analyse
the data. Means and 95% confidence intervals (CI) of CVD risk
and dietary factors were calculated. Participants of both genders
were divided into different groups, according to urbanisation,
education and employment levels, and compared. Estimated
significant differences between rural and urban participants were
determined with analysis of variance using the general linear
model (GLM) multivariate procedure. Univariate analysis was
used to further explore the influence of education on CVD risk
factors and dietary intakes.
Employment was used as a proxy for income, and pairwise
comparisons using GLM multivariate procedure was done for
comparing the three groups (not answered, employed and not
employed). Tests were considered significant at
p
<
0.05.
Results
The total energy as well as macronutrient intakes and some
selected micronutrient levels are shown in Table 1. This shows
that mean total energy intakes of urban men and women were
significantly higher than those of rural men and women. It can
therefore be expected that other nutrient intakes would also be
higher in urban subjects because more food was consumed.
However, if differences in the percentages of energy
contributed by the different macronutrients are compared, it is
clear that not only total amounts of food, but also types of foods
and, therefore, dietary patterns differed between urban and rural
subjects. In urban men, the contributions of total protein, animal
protein, total fat, saturated fat, and total carbohydrates to total
energy were 12.5, 5.6, 25.3, 6.3 and 56.5%, respectively. In
rural men the corresponding figures were 10.8, 3.2, 17.7, 3.9
and 63.1%. The same pattern was observed when urban and rural
women were compared. In rural subjects, animal protein formed
about a third of the total protein, while in urban subjects of both
genders, about half of the total protein was from animal sources.
Total and saturated fat intakes were twice as high in urban
as in rural men and women. Percentage of total energy obtained
from fat increased from rural values of 17.7 and 20.3% to urban
values of 25.3 and 28.3% for men and women, respectively.
This was a major shift from a low-fat, prudent diet followed in
the rural areas to a higher-fat, more Westernised type of diet in
the urban areas.
Mean intakes of total dietary fibre were significantly higher in
urban men and women compared to their rural counterparts. The
percentage increases in energy intake from rural to urban men
and women were 44 and 48%, while that of dietary fibre were
44 and 33% (percentages not shown in Table 1).
Mean intakes of selected key micronutrients (iron, calcium
and vitamin C) were substantially and significantly higher in
urban than rural subjects. For calcium and vitamin C, it was
more than double that of rural groups.
In Table 2 the mean levels of CVD risk factors of urban men
and women are compared to that of their rural counterparts.
Rural women were slightly but significantly younger than urban
women. There were no significant differences in total and high-
density lipoprotein (HDL) cholesterol levels, but urban women
had significantly higher triglyceride levels than rural women.
Their mean fasting glucose value was also significantly higher.
Urban men and women had significantly higher blood
pressures, and urban women had significantly higher mean
BMI than rural women, although the rural women also had a
mean BMI in the overweight range. Rural men and women
had significantly higher plasma fibrinogen levels. There were
TABLE 1. MEAN (95% CI) OF ENERGYAND SELECTED NUTRIENT INTAKES
Nutrients
Men
Women
Urban (
n
=
399)
Rural (
n
=
347)
Urban (
n
=
605)
Rural (
n
=
659)
Total energy (TE) (kJ)
10054.2 (9681.9–10426.4)
a
6973.3 (6568.7–7377.8)
a
9008.3 (8746.0-9269.6)
b
6107.3 (5854.8–6359.8)
b
Total protein (g)
[% of TE]
74.1 (71.3–76.8)
a
[12.5]
44.4 (41.4–47.4)
a
[10.8]
65.54 (63.7–67.4)
b
[12.4]
39.50 (37.7–41.3)
b
[11.0]
Animal protein (g )
[% of TE]
33.4 (31.9–35.0)
a
[5.6]
13.3 (11.6–14.96)
a
[3.2]
31.2 (30.1–32.2)
b
[5.9]
12.8 (11.8–13.8)
b
[3.6]
Total fat (g)
[% of TE]
67.1 (64.3–69.8)
a
[25.3]
32.4 (29.4–35.3)
a
[17.7]
67.2 (65.1–69.4)
b
[28.3]
32.6 (30.5–34.7)
b
[20.3]
Saturated fat (g )
[% of TE]
16.6 (15.9–17.4)
a
[6.3]
7.2 (6.3–8.0)
a
[3.9]
17.2 (16.6–17.8)
b
[7.3]
7.3 (6.7–7.8)
b
[4.5]
Total carbohydrates (g )
[% of TE]
334.3 (321.3–347.4)
a
[56.5]
258.9 (244.7–273.1)
a
[63.1]
293.7 (284.7–302.8)
b
[55.4]
235.9 (227.1–244.6)
b
[65.7]
Dietary fibre (g)
26.7 (25.6–27.8)
a
18.5 (17.3–19.7)
a
22.7 (22.0–23.4)
b
17.1 (16.4–17.8)
b
Iron (g)
16.7 (16.0–17.4)
a
12.4 (11.6–13.1)
a
14.1 (13.6–14.6)
b
11.1 (10.6–11.5)
b
Calcium (g)
452.0 (429.3–474.6)
a
247.9 (223.2–272.5)
a
450.9 (434.5–467.3)
b
211.4 (195.5–227.2)
b
Vitamin C (g )
42.5 (39.1–45.8)
a
12.6 (9.0–16.2)
a
46.9 (44.0–49.8)
b
15.7 (12.9–18.5)
b
a,b
Means with the same symbol differ significantly (
p
<
0.05); significant differences based on GLM, analysis of variance (ANOVA)
