CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 3, April 2013
68
AFRICA
individual probability weights based on the selection probability
at each stage of selection. Individual weights were post-stratified
by province, gender and age groups according to the 2009
medium mid-year population estimates from Statistics South
Africa, available at:
/
P0302/P03022009.pdf.
Computed estimates and odds ratios were reported with 95%
confidence intervals and a two-tailed
p
-value of 0.05 was used
as the cut-off point for statistical significance. Associations
between key outcomes of hypertension, and socio-demographic
and health variables were evaluated calculating odds ratios (OR).
Multivariate logistic regression was used for evaluation of the
impact of explanatory variables for key outcome of hypertension
(binary dependent variable). All variables statistically significant
at
p
<
0.05 in bivariate analyses were included in the multivariable
models. In the analysis, weighted percentages were reported.
Results
The total sample included 3 840 South African subjects 50
years or older, 44.1% were men and 55.9% were women. The
most prevalent population group was black Africans (74%),
and almost half (49.9%) were between 50 and 59 years old. The
educational level of most participants (71.6%) was lower than
secondary school education and almost two-thirds (64.9%) lived
in an urban area.
A large group (72.4%) of older adults were overweight or
obese, 20.4% were daily tobacco users, 4.0% had had a stroke,
and 9.2% had diabetes. More than half (52.2%) engaged in low
physical activity, two-thirds (67.7%) ate insufficient fruit and
vegetables, and a small proportion (13.7%) were current alcohol
users. A sizeable proportion (17.5%) rated their health status
as bad or very bad, 10.7% reported severe or extreme activity
limitation and 28.1% were out-patients five times or more. The
prevalence rates of hypertension were 77.3% (male 74.4%,
female 79.6%) (Table 1).
The results of the multivariate logistic regression analysis
revealed that the prevalence of hypertension was associated with
being in the Coloured population group, having had a stroke,
being overweight and having had five or more out-patients care
visits in the past 12 months. Prevalence of hypertension was
inversely associated with current alcohol use (Table 2).
Overall, 30.3% of older hypertensive people were aware
of their diagnosis, 24.8% of older hypertensives were taking
treatment in the past two weeks to lower their blood pressure,
and 48.8% of those who were taking antihypertensive treatment
had their blood pressure controlled. Women, older age and more
frequent out-patient visits in the past 12 months were associated
with awareness of their hypertensive status and were taking
treatment to lower their blood pressure in the past two weeks.
However, there were no statistical differences in gender, age and
out-patient visits among those who were taking antihypertensive
treatment and had their blood pressure controlled. Of the total 2
841 hypertensive participants, 1 081 (38.1%) were aware of their
hypertension, 985 (32.7%) were being treated, and 486 (17.1%)
had their hypertension under controll (Table 3).
Discussion
The study found significant rates of hypertension of 77.3%
(male 74.4%, female 79.6%) among older adults (50 years and
older) in South Africa. These rates seemed to be higher than in
a previous survey in South Africa (men 44.0–52.0% and women
51.6–60.4%) in 1998,
3
and similar to other studies such as in
urban Senegal (65.4%),
4
urban Zimbabwe (72%),
5
and Turkey
(71.2–82.2%).
12
The rates were higher than in a number of other
countries including rural Malawi, Rwanda and Tanzania (36.6–
41.0%),
6
Brazil (55%),
9
China (24.2–64.9%),
10,11
and Taiwan
(31.1–38.0%).
13
The study further found that regarding socio-demographics,
with multivariate analysis, being in the Coloured population
group was associated with higher rates of hypertension. This
TABLE 1. SAMPLE CHARACTERISTICSAND PREVALENCE RATE OF
HYPERTENSIONAMONG OLDER SOUTHAFRICANS
Total
sample
Prevalence rate of hypertension
Male
(
n
=
1638)
Female
(
n
=
2202)
Total
All
Age (years)
50–59
60–69
70 and over
3840
1695 (49.9)
1233 (30.6)
912 (19.5)
1159 (74.4)
520 (71.3)
391 (79.4)
248 (75.1)
1683 (79.6)
682 (77.9)
563 (81.6)
438 (80.5)
2842 (77.3)
1202 (74.9)
954 (80.6)
686 (78.4)
Population group
African black
White
Coloured
Indian or Asian
2053 (74.0)
269 (9.3)
655 (12.8)
307 (3.8)
575 (73.1)
92 (75.6)
195 (88.1)
97 (74.1)
975 (80.0)
101 (83.0)
350 (83.1)
117 (78.5)
1550 (77.3)
193 (79.6)
545 (85.0)
214 (76.8)
Marital status
Single
Married
Separated/divorced
Widow
512 (14.3)
2007 (55.9)
230 (5.9)
1020 (23.9)
97 (71.5)
870 (74.2)
60 (66.0)
120 (84.8)
292 (83.1)
571 (74.2)
116 (82.3)
667 (82.6)
389 (80.1)
1441 (74.2)
176 (77.7)
787 (82.9)
Educational level
No schooling
Less than primary
Primary
Secondary
854 (25.2)
803 (24.0)
779 (22.4)
923 (28.3)
231 (78.3)
227 (69.4)
232 (79.2)
261 (74.9)
422 (81.2)
404 (85.6)
364 (79.3)
337 (76.5)
653 (80.2)
631 (78.9)
596 (79.2)
598 (75.8)
Wealth
Low
Medium
High
1482 (40.6)
731 (18.2)
1608 (41.2)
429 (71.1)
197 (74.7)
525 (77.1)
646 (78.7)
377 (79.9)
651 (80.2)
1075 (75.4)
574 (78.3)
1176 (78.6)
Geolocality
Rural
Urban
1276 (35.1)
2561 (64.9)
392 (75.9)
766 (73.7)
524 (78.7)
1157 (80.1)
916 (77.5)
1923 (77.2)
Other conditions
Stroke
Angina
Diabetes
Overweight (BMI
≥
25 kg/m
2
)
Underweight (BMI
<
18.5 kg/m
2
)
Arthritis
139 (4.0)
219 (5.2)
360 (9.2)
2505 (72.4)
184 (4.3)
851 (24.7)
48 (88.2)
62 (76.2)
107 (88.4)
745 (77.3)
51 (64.4)
198 (81.8)
71 (91.5)
114 (76.2)
202 (90.2)
1253 (82.8)
63 (66.8)
472 (83.0)
119 (90.0)
176 (76.2)
309 (89.6)
1998 (80.5)
114 (65.5)
670 (82.6)
Daily tobacco use
810 (20.4) 295 (74.6) 315 (76.3) 610 (75.4)
Alcohol use (past month)
557 (13.7) 248 (66.6) 151 (77.5) 399 (70.3)
Physical activity
Low
Moderate
High
2100 (52.2)
692 (16.6)
1044 (31.2)
567 (73.2)
233 (79.6)
357 (73.4)
940 (79.0)
302 (76.9)
440 (82.1)
1507 (76.6)
535 (78.1)
797 (78.1)
Insufficient fruit and vegetables 2817 (67.7) 834 (77.3) 1245 (77.0) 2079 (77.1)
Subjective health status
Very/good
Moderate
Bad/very bad
1469 (37.9)
1681 (44.9)
617 (17.5)
486 (71.3)
495 (78.2)
177 (73.9)
565 (75.4)
834 (80.9)
281 (84.4)
1051 (73.4)
1329 (79.8)
458 (79.9)
Activity limitation
None
Mild
Moderate
Severe/extreme
1465 (38.5)
625 (16.7)
1275 (34.2)
370 (10.7)
487 (73.6)
191 (71.6)
369 (75.9)
103 (78.5)
566 (74.8)
297 (80.5)
628 (81.0)
178 (89.6)
1053 (74.2)
488 (76.5)
997 (78.9)
281 (85.8)
Social cohesion index (range
9–72); mean (SD)
22.1 (6.5) 21.9 (6.2) 21.4 (6.1) 21.6 (6.1)
Outpatient visits in past 12 months
0
1–4
5 or more
1176 (38.2)
908 (33.7)
941 (28.1)
372 (72.2)
271 (76.2)
282 (80.4)
464 (74.5)
414 (79.2)
513 (86.4)
836 (73.3)
685 (77.9)
795 (84.2)
