Cardiovascular Journal of Africa: Vol 30 No 5 (October 2019)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 5, September/October 2019 258 AFRICA
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
Abstract
Objectives: Previous studies suggest a strong relationship
between obesity and hypertension. This study aimed at evalu-
ating 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-
to14-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
Submitted 12/4/18, accepted 11/4/19
Cardiovasc J Afr 2019; 30: 258–261
DOI: 10.5830/CVJA-2019-017
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.11Nevertheless
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
Department of Geography and Environmental Sciences,
University of Fort Hare, Alice, South Africa
A Chungag, BA, MSc, MPhil,
W Nel, BSc, BSc (Hons), MSc, PhD
Department of Human Biology, Walter Sisulu University,
Mthatha, South Africa
CM Tata, BSc, BSc (Hons), MSc, PhD
CR Sewani-Rusike, BSc, BSc (Hons), MSc, PhD, MB ChB
Department of Biological and Environmental Sciences,
Walter Sisulu University, Mthatha, South Africa
BN Nkeh-Chungag, BSc, BSc (Hons), MSc, PhD, MPH,