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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 2, March/April 2018
AFRICA
75
as absolute frequencies and percentages or means and standard
deviations (SD), as appropriate.
To facilitate comparisons with other studies, the prevalence
of the three conditions under study was determined for three age
groups: 15 to 64, 18 to 64 and 25 to 64 years. Logistic regression
models were fitted to the categorical variable of age because of its
known effect on hypertension, diabetes and hypercholesterolaemia.
Gender-specific adjusted odds ratios (OR) were estimated for
each variable (age, residence, education, BMI, abdominal obesity,
tobacco and alcohol consumption) related to the conditions
studied. A 95% confidence interval (95% CI) and a significance
level of
p
<
0.05 were set for all applicable determinations.
Results
The mean age of this population was 32.5 years (SD 13.6) with
63.0% (
n
=
1 482) women and the majority (81.0%) living in urban
settings. Nearly 10% had never received any formal education,
with men having completed more school years. Overall, almost a
quarter of participants had abdominal obesity (36.5% of women
and 12.4% of men), 6.8% were obese (10.6% of women and 2.8%
of men), 6.2% were smokers (2.7% of women and 10.0% of men)
and approximately two-fifths consumed alcohol occasionally or
frequently, with a higher proportion of frequent drinkers among
men (24.6 vs 10.9%) (Table 1).
The prevalence of hypertension in the general population
was 18.0%, reaching 20.0% in those over 18 years of age, and
26.6% in those aged 25 to 64 years (Table 2). This prevalence was
always higher among women than men, but with no statistically
significant relationship (data not shown).
The overall prevalence of diabetes among participants aged
15 to 64 years was 9.2%; the prevalence among those over 18
years old was 9.8%, and 11.9% in those aged over 25 years (Table
2). Men had a higher OR than women for diabetes of 1.4 (95%
CI: 1.0–1.8, data not shown).
Similar to that of hypertension and diabetes, the prevalence
of hypercholesterolaemia was higher in the older age groups,
with an estimated 5.5% in participants aged 25 to 64 years, and
a lower prevalence of 4.0% in the overall population (Table 2).
Women had an OR of 2.3 (95% CI: 1.3–4.0, data not show) for
hypercholesterolaemia.
Only five participants (0.2%; 95%CI: 0.1–0.4, data not shown)
presented all three conditions, but 22.0% (95% CI: 18.4–26.2,
data not shown) of hypertensive participants had an associated
condition, as did 37.2% (95% CI: 31.1–43.7, data not shown)
of participants with diabetes and 47.9% (95% CI: 36.7–59.3,
data not shown) of those with hypercholesterolaemia. The most
common associations were hypertension and diabetes, present in
71 individuals (3.0%; 95% CI: 2.4–3.7, data not shown).
The prevalence of hypertension was higher in rural areas (26.9
vs 15.9% in urban areas) for both genders. Individuals with lower
levels of education had a higher prevalence of hypertension,
with women with no formal education presenting an OR for
hypertension of 4.3 (Table 3).
Hypertension was higher among the obese (34.9% of women
and 48.5% of men) and individuals with abdominal obesity
(32.5% of women and 45.7% of men), with a higher OR in men
for both conditions (Table 3). Hypertension prevalence was also
higher among current smokers (50.0% in women and 20.4% in
men) and frequent alcohol drinkers (28.0% in women and 24.3%
in men). Men presented a higher OR for hypertension than
women, related to the consumption of alcohol (Table 3).
Residents in urban areas presented a higher prevalence of
diabetes, with a significantly higher OR for diabetes in men.
Participants with lower education levels had a higher prevalence
of diabetes, but without statistical significance (Table 4).
With regard to anthropometric variables, there was a higher
prevalence of diabetes among obese participants (17.1% in
Table 1. Socio-demographic, anthropometric and behavioral
characteristics of the population (Caxito, 2016)
Age (years) (
n
=
2 354)
All participants
(
n
=
2 354)
Female
(
n
=
1 222)
Male
(
n
=
1 132)
% (95% CI)* % (95% CI)* % (95% CI)*
15–24
36.2 (34.3–38.1) 30.1 (27.6–32.7) 42.7 (39.9–45.6)
25–34
25.9 (24.2–27.7) 25.4 (23.0–27.9) 26.5 (24.0–29.1)
35–45
16.1 (14.7–17.6) 18.7 (16.6–20.9) 13.3 (11.5–15.4)
45–54
12.6 (11.3–14.0) 15.3 (13.4–17.4) 9.7 (8.1–11.6)
55–64
9.2 (8.1–10.4) 10.6 (9.0–12.4) 7.8 (6.3–9.5)
Residence (
n
=
2 354)
Urban
81.0 (79.4–82.5) 81.2 (78.9–83.3) 80.8 (78.4–83.0)
Rural
19.0 (17.5–20.6) 18.8 (16.7–21.1) 19.2 (17.0–21.6)
Education (years completed) (
n
=
2 348)
None
9.3 (8.2–10.5) 16.6 (14.6–18.8) 1.4 (0.9–2.3)
1–4
23.1 (21.5–24.9) 34.5 (31.9–37.2) 10.9 (9.2–12.8)
5–9
42.2 (40.2–44.2) 35.7 (33.1–38.5) 49.2 (46.3–52.1)
> 10
25.4 (23.7–27.2) 13.1 (11.4–15.2) 38.5 (35.7–41.4)
BMI class (kg/m
2
) (
n
=
2 354)
Underweight (
<
18.5)
11.3 (10.1–12.6) 10.2 (8.7–12.1) 12.5 (10.7–14.5)
Normal (18.5–24.9)
66.1 (64.1–67.9) 58.7 (55.9–61.4) 74.0 (71.4–76.5)
Overweight (25.0–29.9)
15.8 (14.4–17.3) 20.5 (18.4–22.9) 10.7 (9.0–12.6)
Obese (
≥
30)
6.8 (5.9–7.9) 10.6 (9.0–12.4) 2.8 (2.0–4.0)
Abdominal obesity (
n
=
2 354)
No
75.1 (73.3–76.8) 63.5 (60.8–66.2) 87.6 (85.6–89.4)
Yes
24.9 (23.2–26.7) 36.5 (33.8–39.2) 12.4 (10.6–14.4)
Tobacco smoking (
n
=
2 342)
Non-current
93.8 (92.7–94.7) 97.3 (96.2–98.1) 90.0 (88.1–91.6)
Current
6.2 (5.3–7.3)
2.7 (1.9–3.8) 10.0 (8.4–11.9)
Alcohol consumption (
n
=
2 335)
No consumption
63.8 (61.8–65.7) 69.5 (66.9–72.0) 57.6 (54.7–60.4)
Occasional (
<
3 days per week) 18.8 (17.2–20.4) 19.6 (17.5–21.9) 17.8 (15.7–20.2)
Frequent (
≥
3 days per week) 17.5 (16.0–19.1) 10.9 (9.2–12.7) 24.6 (22.2–27.2)
*Post-stratification weights used as described in the methods section.
Table 2. Prevalence of hypertension, diabetes and hypercholesterolaemia by gender and age (Caxito, 2016)
All Participants
Female
Male
15
–
64 years
(
n
=
2 354)
18
–
64 years
(
n
=
2 100)
25
–
64 years
(
n
=
1 503)
15
–
64 years
(
n
=
1 222)
18
–
64 years
(
n
=
1 116)
25
–
64 years
(
n
=
854)
15
–
64 years
(
n
=
1 132)
18
–
64 years
(
n
=
984)
25
–
64 years
(
n
=
649)
Hypertension, % (95% CI)
18.0
(16.5–19.6)
20.0
(18.4–21.8)
26.6
(24.4–28.9)
20.0
(17.8–22.3)
21.8
(19.5–24.3)
27.8
(24.9–30.8)
15.9
(13.9–18.1)
18.1
(15.8–20.6)
25.1
(21.9–28.6)
Diabetes, % (95% CI)
9.2
(8.1–10.4)
9.8
(8.6–11.2)
11.9
(10.3–13.6)
8.9
(7.4–10.6)
9.3
(7.8–11.2)
10.8
(8.9–13.0)
9.6
(8.0–11.4)
10.4
(8.7–12.5)
13.5
(11.0–16.3)
Hypercholesterolaemia, %
(95% CI)
4.0
(3.2–5.0)
4.4
(3.5–5.5)
5.5
(4.4–6.9)
5.6
(4.3–7.2)
6.0
(4.7–7.8)
7.4
(5.7–9.5)
2.0
(1.2–3.2)
2.4
(1.5–3.8)
2.9
(1.8–4.8)