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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
72
VOLUME 16 NUMBER 2 • NOVEMBER 2019
Ellisras Longitudinal Study 2017: association of
hypertension with increasing levels of adiposity in 10- to
14-year-old boys and girls in the Eastern Cape (ELS 31)
A CHUNGAG, CM TATA, CR SEWANI-RUSIKE, W NEL, BN NKEH-CHUNGAG
Correspondence to: A Chungag
Department of Geography and Environmental Sciences, University of Fort
Hare, Alice, South Africa
e-mail:
achunag@ufh.ac.zaCM Tata
Department of Human Biology, Walter Sisulu University, Mthatha,
South Africa
BN Nkeh-Chungag
Department of Biological and Environmental Sciences, Walter Sisulu
University, Mthatha, South Africa
Previously published in
Cardiovasc J Afr
2019;
30
: 258–261
S Afr J Diabetes Vasc Dis
2019;
16
: 72–75
Abstract
Objectives:
Previous studies suggest a strong relationship
between obesity and hypertension. This study aimed
at evaluating the prevalence of hypertension and pre-
hypertension in 10- to 14-year-old boys and girls in the
Eastern Cape Province of South Africa and to determine
the association between blood pressure parameters and
selected measures of adiposity.
Methods:
A cross-sectional, school-based study of 540 10-
to 14-year-old children from seven schools in the Eastern
Cape Province was carried out. Anthropometry and blood
pressure parameters were determined.
Results:
All measures of adiposity and blood pressure were
significantly higher in the girls (
p
< 0.05). The prevalence of
hypertension and pre-hypertension was over 20 and 12%,
respectively. Systolic blood pressure and pulse pressure were
associated (
r
> 0.27;
p
< 0.05) with increasing levels of
adiposity.
Conclusion:
This study highlights the importance of weight-
control strategies for the prevention of hypertension in
these adolescents and later on in life.
Keywords:
adolescent, school, hypertension, pre-hypertension,
adiposity, obesity
An increasing number of studies are reporting hypertension and
pre-hypertension in the paediatric population.
1-3
Once considered
rare or secondary only to known causes, essential hypertension is
now a reality among children.
4
Lifestyle risk factors for hypertension
are generally very subtle to find since most children in this phase of
life do not smoke or drink and are mostly active.
Hypertension in children has been associated with family history
and low birth weight.
5
However, as in the adult population, the
prevalence of obesity and overweight have reached pandemic
levels in children in rural and urban communities in developing
and industrialised countries.
6
Consequently, complications of
overweight and obesity such as hypertension and diabetes have
also become commonplace in children.
7
Indeed, studies in the USA suggest that blood pressure increases
correlate with body mass index in children and adolescents.
8
Kemp
et al.
9
showed an eight and 20% prevalence of pre-hypertension
and hypertension, respectively, in grade 1 children in a rural South
African community. Furthermore, we previously showed that the
prevalences of pre-hypertension and hypertension in adolescents
in Mthatha were 13.6 and 22% in males and 16.5 and 20.9% in
females, respectively.
3
Although studies have demonstrated hypertension in children, it
remains under-diagnosed or not diagnosed at all since blood pressure
measurement is not routine in paediatric patients. Importantly,
adult criteria for the diagnosis of hypertension are often applied to
children and adolescents. Consensus guidelines for defining pre-
hypertension and hypertension in children require the systolic and
diastolic blood pressure values to be converted to percentiles for
age, gender and height,
10
which is often a challenge for the already
overworked physicians in developing countries. This has therefore
led to the perception that children do not suffer from hypertension,
with the consequent under-diagnosis of the problem.
11
Nevertheless
hypertension in childhood had been shown to track to adulthood,
when it progresses to established hypertension.
12
Overweight and obesity in childhood are risk factors for
hypertension in children.
13
Overweight and obesity, as expressed by
various measurements of adiposity, have shown relationships with
hypertension. In this study we explored the impact of increasing
adiposity on blood pressure and consequently hypertension.
Methods
A cross-sectional study was carried out in seven selected middle
schools in the Eastern Cape Province, South Africa, from May to
September 2016. Data were collected once during this period
from participating children. Ten- to 14-year-old boys and girls were
recruited into the study in order to determine gender differences on
adiposity and blood pressure.
Ethical clearance was obtained from the University of Fort Hare
(CH1011SCHU01) and consent was obtained from parents and
children involved in the study and from the schools’ authorities.
All consenting children who were not pregnant or lactating or
suffering from any debilitating condition were included in the
study. Data were collected on the school premises where the
children were comfortable and had a sense of security. Boys and
girls were required to rest in a seated position for 10 minutes, after
which their right upper arms were fitted with appropriate arm-size
cuffs and blood pressure was measured at three-minute intervals