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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 4, July/August 2017
AFRICA
237
dl (0.96–1.68 mmol/l); hypocholesterolaemia:
<
37 mg/dl (0.96
mmol/l) and hypercholesterolaemia:
>
65 mg/dl (1.68 mmol/l).
LDL-C ranges were defined for women as normal: 100–150
mg/dl (2.59–3.89 mmol/l), hypocholesterolaemia:
<
100 mg/
dl (
<
2.59 mmol/l) and hypercholesterolaemia:
>
150 mg/dl (
>
3.89 mmol/l). LDL-C ranges were defined for men as normal:
110–160 mg/dl (2.85–4.14 mmol/l), hypocholesterolaemia:
<
110
mg/dl (
<
2.85 mmol/l) and hypercholesterolaemia:
>
160 mg/dl
(
>
4.14 mmol/l).
Triglyceride ranges were defined for women as normal:
35–140 mg/dl (0.4–1.58 mmol/l), hypotriglyceridaemia:
<
35 mg/
dl (
<
0.4 mmol/l) and hypertriglyceridaemia:
>
140 mg/dl (
>
1.58
mmol/l). Triglyceride ranges were defined for men as normal:
45–175 mg/dl (0.51–1.98 mmol/l), hypotriglyceridaemia:
<
45
mg/dl (
>
0.51 mmol/l) and hypertriglyceridaemia:
>
175 mg/dl
(
>
1.98 mmol/l).
15
Statistical analysis
All statistical tests were performed using SPSS software (version
22.0.0.0; IBM Corp). For quantitative variables, data are
presented as mean or median
±
standard error of means (SEM).
The Student’s
t
-test for independent samples or Wilcoxon–
Mann–Whitney test were used to compare the means or medians
of two groups, while one-way ANOVA or the Kruskal–Wallis
test were used to compare the means or medians of more than
two groups. For qualitative variables, data are presented in tables
using numbers and percentages, and chi-squared or Fisher’s exact
tests were used to compare characteristics between the groups.
Spearman’s correlations were used to test possible correlations
between two parameters. The results were considered statistically
significant for
p
<
0.05.
Results
The study population was distributed equally between men and
women in the two regions, north and south. The distribution
according to age group showed a significant difference (
p
<
0.001) between the two regions.
Populations from the south consumed more alcohol than
those in the north, who drank little or nothing (
p
<
0.001). The
tobacco consumption was zero in the north and in the south very
low (
p
<
0.03).
The intense or moderate practice of sport was very low in the
north compared to the south (
p
<
0.001). However, northerners
had physical rather than intellectual professions compared to
people of the south (
p
<
0.001).
The percentage consumption of polyunsaturated oils was
higher among the northerners compared to southerners. The
majority of the southern population consumed both crude and
refined palm oils, while a small portion of the southern people
consumed only crude palm oil. In the north, people consumed
mainly soybean oil and refined palm oil (Table 1).
WCandBMI were higher among southerners than northerners
(
p
= 0.01 and 0.04, respectively). However, the percentage of
obese population, determined by measuring either the WC
(north 61%, south 69%) or BMI (north 21%, south 21%), was
statistically comparable between the two regions.
The average and range of TC, HDL-C, LDL-C and TG
levels were not significantly different according to region. By
contrast, BG levels, SBP and DBP were higher in the northern
populations than the south (
p
= 0.024,
p
<
0.001, respectively).
The percentages of individuals with diabetes, 10% in the north
and 2% in the south, were not statistically different. There was
however an over-representation of hypertension (SBP and DBP)
in the north compared to the south (
p
<
0.001) (Table 2).
In men from the two regions, there was no statistically
significant difference between WC and BMI. By contrast,
women from the south had a WC and BMI statistically higher
than northern women (
p
= 0.001 and 0.005, respectively). The
percentage of obesity was statistically higher among northern
than southern men, based on BMI (
p
= 0.03) but not WC. By
contrast, the percentage of obese women was higher in the south
compared to the north, based on WC (
p
<
0.001) but not BMI.
BG, TC, HDL-C, LDL-C and TG levels were not significantly
different between women and men in the two regions. Both SBP
and DBP were higher in men from the north than from the
south (
p
<
0.001), whereas those parameters were comparable in
women from the two regions.
Northern men had a higher incidence of diabetes (16%)
than men from the south (4%) (
p
= 0.027). Similarly, a greater
percentage of men from the north had a SBP and DBP higher
than that of men from the south (
p
<
0.001). The incidence of
hypertension was higher among women from the north than
from the south (
p
= 0.01) (Table 3).
The characteristics of the populations showed that there was
a significant difference in age between the volunteers from the
north and south. Taking this into consideration, anthropometric
Table 1. Characteristics of the study population
Characteristics
Population
Percentage (%)
p
-value
Total
number
North
(
n
= 89)
South
(
n
= 103) North South
Gender
Female
101
44
57
49
55 0.23
Male
91
45
46
51
45
Age (years)
35–51
107
64
43
72
42
<
0.001
51–65
85
25
60
28
58
Alcohol use
None
96
88
8
99
8
<
0.001
Occasionally
88
0
88
0
85
Regularly
8
1
7
1
7
Tobacco use
Yes
9
0
9
0
9 0.03
No
183
89
94
100
91
Sport
Yes
35
4
31
5
30
<
0.001
No
157
85
72
95
70
Profession
Physical
146
83
63
93
61
<
0.001
Intellectual
46
6
40
7
39
Oils consumed
Crude palm oil
30
0
30
0
29
<
0.001
Crude and
refined palm oils
71
0
71
0
69
Soybean oil and
refined palm
75
75
0
84
0
Other poly-
unsaturated oils
16
14
2
16
2
p
-value of chi-squared or Fischer’s exact test for the comparison of percentages
between the two regions.