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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
26
VOLUME 17 NUMBER 1 • JULY 2020
This is a cause for concern in Botswana where about a third of
adults are hypertensive.
32,33
As childhood hypertension progresses
to adulthood, the findings suggest that a significant proportion
of our participants are at high risk of becoming hypertensive in
adulthood.
34
We did not observe an urban–rural difference in the
prevalence of hypertension. However, our participants from the
rural school were significantly older than their urban counterparts,
making it difficult to compare the two populations.
Both hypertension and pre-hypertension were more common
in the male students than the females in our study. Our finding
may be explained by the fact that male students were significantly
older than their female colleagues. Results from the most recent
meta-analysis on hypertension in adolescents in Africa however
showed no difference between boys and girls in the prevalence of
hypertension.
30,35-37
Similar to other studies, overweight/obesity was associated
with up to a four-fold increased risk of hypertension among our
participants.
5, 29,35,36,38-41
A similar link between obesity and CVD
has been established among adults.
42
Overweight/obesity and
hypertension are some of the components of the metabolic
syndrome, an indicator of high risk for CVD as well as type 2
diabetes.
43
The burden of overweight and obesity among our participants
is consistent with reports from other SSA countries where between
2.5 and 10.6% of adolescents are overweight or obese.
2,39,41,44
There
is evidence that the increase in overweight/obesity is associated with
urbanisation.
2
Although we did not see a rural–urban difference
in the prevalence of overweight/obesity, earlier data from urban
students in Botswana reported a higher proportion of overweight
and obesity.
45
Consistent with other studies, overweight/obesity
affected more girls than boys.
29
Although none of the students was found to have diabetes
mellitus, 1.6% of participants had IFG. As for the other components
of the metabolic syndrome, IFG is a cardiovascular risk factor.
43
This
is in contrast to findings from Cote d’Ivoire where 0.4 and 14.5%
of adolescents had diabetes mellitus and IFG, respectively.
46
The
reasons for this discrepancy are not clear.
A small proportion of both rural and urban students reported
using tobacco. This is lower than earlier data from Botswana, in
which 10% of the students were current tobacco smokers, and
up to 29% reported having tried smoking.
47
Our findings are
also inconsistent with the Global Youth Tobacco Survey (GYTS),
which reported a prevalence of 10–33% among 13–15-year-
olds.
48
Tobacco use was more common among males than
females, consistent with a previous study in Botswana.
32
The lower
prevalence of tobacco use among our participants was possibly due
to under-reporting of tobacco use because of its prohibited use
within schools in Botswana.
Only about 9% of our students reported using alcohol. The
figure is lower than what would be expected in a country where
nearly half (48.4%) of adults are said to consume alcohol regularly,
32
and again may be due to under-reporting. Similar to a study in
Australia, our urban students were more likely to use alcohol than
their rural counterparts.
49
It is possible that urban students have
more access to alcohol than those in the rural setting, contributing
to these findings.
Table 3.
Factors associated with hypertension among students at Shakawe and St Joseph’s senior secondary schools (
n
= 252)
Bivariate analysis
Multivariate analysis
Variable
Crude OR
95% CI
p
-value
Adjusted
95% CI
p
-value
Gender
Female
1 (ref)
1 (ref)
1 (ref)
1 (ref)
1 (ref)
Male
3.5
1.66–7.44
0.001
* 4.31
1.83–10.13
< 0.001
School
Shakawe (rural)
1
St Joseph’s (urban)
0.59
0.28–1.25
0.168*
0.62
0.26–1.44
0.263
Age
0.98
0.66–1.46
0.923
Alcohol intake
No
1 (ref)
1 (ref)
Yes
3.57
0.47–27.44
0.221
4.86
0.44–54.0
0.198
Smoking
No
1 (ref)
1 (ref)
Yes
4.65
0.75–28.91
0.1
7.47
0.544–102.59
0.132
BMI category
Normal weight
1 (ref)
1 (ref)
Underweight
0.64
1.03–7.13
0.563
0.457
0.089–2.345
0.348
Overweight/obese
2.72
1.03–7.13
0.043*
2.998
0.716–12.56
0.133
WC
1.07
1.02–1.13
0.005
Fasting blood glucose
1.32
0.59–2.93
0.496
Physical activity
Inactive
1.19
0.51–2.77
0.681
–
–
–
Minimally active
0.65
0.24–1.76
0.393
–
–
–
Highly active
1 (ref)
1 (ref)
–
–
–
Family history of hypertension
0.73
0.31–1.69
0.458
–
–
–
Family history of diabetes
1.022
0.22–4.75
0.980
–
–
–
Family history of stroke
0.425
005–3.33
0.415
–
–
–
PreHPT: pre-hypertension; HPT: hypertension; BMI: body mass index; WC: waist circumference; IFG: impaired fasting glucose.