Cardiovascular Journal of Africa: Vol 30 No 3 (May/June 2019)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 3, May/June 2019 146 AFRICA
Ellisras Longitudinal Study 2017: Childhood underweight
and blood pressure status in a rural black population of
South Africa (ELS 26)
Peter M Mphekgwana, Herbert M Makgopa, Kotsedi Dan Monyeki, Johanna M Malatji, Thembinkosi E Mabila
Abstract
Aim: Childhood underweight is a problem being faced by rural
black South African populations but little is known about its
risk factors. The aim of this study was to investigate the risk
factors related to childhood underweight in rural black South
African children within the area known as Ellisras.
Methods: A cross-sectional study was conducted as part of
the ongoing Ellisras Longitudinal Study. The current study
comprised a total of 1 811 pre-primary and primary school
children (934 males and 877 females) aged between five and
16 years. The chi-squared automatic interaction detection
(CHAID) decision tree model was used to identify factors and
determine their relationships with childhood underweight.
Results: A total of 1 811 children were involved in the study,
of whom about 81% were severely underweight. The CHAID
model showed that the variables: nutrition, age group, gender
and school level were the four main predicting variables
affecting childhood underweight. Hypertension was not
significantly associated with childhood underweight.
Conclusions: The prevalence of childhood underweight was
found to be high in children aged between five and 16
years. To address this problem, well-thought-out intervention
systems are need.
Keywords: childhood underweight, blood pressure, hypertension,
risk factor, CHAID decision tree
Submitted 14/4/18, accepted 31/10/18
Published online 4/6/19
Cardiovasc J Afr 2019; 30: 146–150
DOI: 10.5830/CVJA-2018-061
Childhood underweight is internationally recognised as a public
health concern associated with negative health outcomes.1-4
The problem is reported to be on the rise in developing
countries despite increased efforts to address it.5,6 In Africa, its
prevalence was projected to have increased from 24.0% in 1990
to 26.8% in 2015, an increase of 12%. 7 Childhood underweight
is also a problem in South Africa, especially among school-aged
children.8 Available data indicate that approximately one in 10
children is underweight in South Africa,9 and this phenomenon
is at higher levels in rural areas. 9
Previous studies in this field have identified various factors
that are believed to be associated with childhood underweight.
These include, among others, socio-demographics such as age
(15–24 years), gender (female), race (black), lower educational
level, lower household income, behavioural (food insecurity, low
energy levels, inadequate food intake, diets low in diversity and
with insufficient nutrient density, as well as tiredness and poor
perceptions of body image or fear of being fat).9-12
In addition to socio-demographic and behavioural factors,
cardio-metabolic risk factors such as hypertension have also been
reported to be associated with underweight. The co-existence of
both these conditions with underweight have proved to cause
adverse cardiovascular events.13
Although available, few studies exist in South Africa,
particularly in the studyarea investigating childhoodunderweight,
hypertension and associated risk factors. Yet research studies
demonstrate a growing prevalence of underweight during the
ageing process. 14 Therefore, this study aimed to investigate the
prevalence and associated factors of childhood underweight in a
rural sample of young black South Africans who participated in
the Ellisras Longitudinal Study.
Methods
This cross-sectional study is part of the ongoing Ellisras
Longitudinal Study (ELS) design that started in 1996. Sampling
was conducted as reported elsewhere. 15 Briefly this study
comprised 1 811 pre-primary and primary school children (934
males and 877 females), aged between five and 16 years, who
were evaluated in 2000.
The Ethics Committee of the University of Limpopo granted
ethical approval prior to the study. Written informed consent was
obtained from the parents or guardians of the children.
Height was measured to the nearest 0.5 cm using a stadio-
meter.16 Weight was taken to the nearest 0.1 kg using a calibrated
digital bathroom scale.16 Body mass index (BMI) was calculated
as weight in kg divided by the square of height in metres. BMI =
weight (kg)/height (m2).17
Growth charts published in 2000 from the Centre for Disease
Control and Prevention (CDC) were used to plot BMI against
age in both genders.18 Body mass index percentile and BMI
z-score were estimated according to these charts. A BMI value
at or greater than the 95th percentile was defined as obesity and
Research Administration and Development, University of
Limpopo, Sovenga, South Africa
Peter M Mphekgwana, MSc
Thembinkosi E Mabila, PhD
Department of Pathology and Medical Sciences, University
of Limpopo, Sovenga, South Africa
Herbert M Makgopa, BSc Hons
Department of Physiology and Environmental Health,
University of Limpopo, Sovenga, South Africa
Kotsedi Dan Monyeki, PhD, MPH,
Johanna M Malatji, STD