Exploring the paradox: double burden of malnutrition in rural South Africa
Date
2011-03-09
Authors
Kimani, Elizabeth Wambui
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Abstract
Background: In low- to middle-income countries, rising levels of overweight and obesity are a
result of multiple transitions, in particular, a nutrition transition. Consequently, in these countries,
metabolic diseases are contributing increasingly to disease burden, despite the persisting burden of
undernutrition and infectious diseases. Understanding the patterns and factors associated with
persistent undernutrition and emerging obesity in children and adolescents, and concomitant risk
for metabolic disease, is therefore of criticial importance. This should contribute to public health
policy on interventions to prevent adult disease.
Aims: To better understand the double burden of malnutrition in a poor, high HIV prevalent,
transitional society in a middle-income country; In so doing, to inform policies and interventions to
address the double burden of malnutrition.
Methods: A cross-sectional growth survey was conducted in 2007 targeting 4000 children and
adolescents 1-20 years of age living in rural South Africa. The survey was nested within the
ongoing Agincourt Health and Socio-demographic Surveillance System, which acted as the
sampling frame and also provided data for explanatory variables. Anthropometric measurements
were performed on all participants using standard procedures. In addition, HIV testing was done
on children aged 1 to 5 years and Tanner pubertal assessment was conducted among adolescents
9-20 years. A one-year follow-up of HIV positive children included a matched control group of
HIV negative counterparts. Data collection involved both quantitative and qualitative methods.
Growth z-scores were used to determine stunting, underweight and wasting and were generated
using the 2006 WHO growth standards for children up to five years and the 1977 NCHS/WHO
reference for older children. Overweight and obesity were determined using the International
Obesity Task Force cut-offs for BMI for children aged up to 17 years and adult cut offs of BMI
=25 and =30 kg/m2 for overweight and obesity respectively for adolescents 18 to 20 years. Waist
circumference cut-offs of =94cm for males and =80cm for females, and waist-to-height ratio of
0.5 for both sexes, were used to determine central obesity and hence metabolic disease risk in
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adolescents. Descriptive analysis described patterns of nutritional status by age, sex, pubertal
stage and HIV status. Linear and logistic regression was done to determine predictors of
nutrional outcomes. A p-value of <0.05 was considered statistically significant.
Results: Prevalence of undernutrition, particularly stunting, was substantial: 18% among
children aged 1-4 years, with a peak of 32% in children at one year of age. Stunting and
underweight were also substantial in adolescent boys, with underweight reaching a peak of 19%
at 14 years of age. Concurrently, the prevalence of combined overweight and obesity, almost
non-existent in boys, was prominent among adolescent girls, increasing with age, and reaching a
peak of 25% at 18 years. Risk for metabolic disease using waist circumference cut-offs was
substantial among adolescents, particularly girls, increasing with sexual maturation, and reaching
a peak of 35% at Tanner stage 5. Prevalence of HIV in children aged 1-4 years was 4.4%. HIV
positive children had poorer nutritional outcomes than that of HIV negative children in 2007.
The impact of paediatric HIV on nutritional status at community level was, however, not
significant. Significant predictors of undernutrition in children aged 1-4 years, documented at child,
maternal, household and community levels, included child’s HIV status, age and birth weight;
maternal age; age of household head; and area of residence. Significant predictors of
overweight/obesity and risk for metabolic disease in adolescents aged 10-20 years, documented at
individual/child and household levels included child’s age, sex and pubertal development; and
household-level food security, socio-economic status, and household head’s highest education level.
There was a high acceptance rate for the HIV test (95%). One year following the test, almost all
caregivers had accepted and valued knowing their child’s HIV status, indicating that it enhanced
their competency in caregiving. Additionally, nutritional status of HIV positive children had
improved significantly within a year of follow-up.
Conclusions: The study describes co-existing child stunting and adolescent overweight/obesity
and risk for metabolic disease in a society undergoing nutrition transition. While likely that this
profile reflects changes in nutrition and diet, variation in infectious disease burden, physical
activity patterns, and social influences need to be investigated. The findings are critical in the
wake of the rising public health importance of metabolic diseases in low- to middle-income
countries, despite the unfinished agenda of undernutrition and infectious diseases. Clearly,
policies and interventions to address malnutrition in this and other transitional societies need to be
double-pronged. In addition, gender-biased nutritional patterns call for gender-sensitive policies
and interventions. The study further documents a significant role of paediatric HIV on nutritional
status, and the potential for community-based paediatic HIV testing to ameliorate this. Targeted
early paediatric HIV testing of exposed or at risk children, followed by appropriate health care for
infected children, may improve their nutritional status and survival.
Description
PhD, Faculty of Health Sciences, University of the Witwatersrand
Keywords
nutrition transition, double burden of malnutrition, stunting, underweight, wasting, overweight, obesity, metabolic disease risk, HIV, rural South Africa, low-to-middle income countries