Exploring the paradox: double burden of malnutrition in rural South Africa

[摘要] Background: In low- to middle-income countries, rising levels of overweight and obesity are aresult of multiple transitions, in particular, a nutrition transition. Consequently, in these countries,metabolic diseases are contributing increasingly to disease burden, despite the persisting burden ofundernutrition and infectious diseases. Understanding the patterns and factors associated withpersistent undernutrition and emerging obesity in children and adolescents, and concomitant riskfor metabolic disease, is therefore of criticial importance. This should contribute to public healthpolicy 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 toaddress the double burden of malnutrition.Methods: A cross-sectional growth survey was conducted in 2007 targeting 4000 children andadolescents 1-20 years of age living in rural South Africa. The survey was nested within theongoing Agincourt Health and Socio-demographic Surveillance System, which acted as thesampling frame and also provided data for explanatory variables. Anthropometric measurementswere performed on all participants using standard procedures. In addition, HIV testing was doneon children aged 1 to 5 years and Tanner pubertal assessment was conducted among adolescents9-20 years. A one-year follow-up of HIV positive children included a matched control group ofHIV negative counterparts. Data collection involved both quantitative and qualitative methods.Growth z-scores were used to determine stunting, underweight and wasting and were generatedusing the 2006 WHO growth standards for children up to five years and the 1977 NCHS/WHOreference for older children. Overweight and obesity were determined using the InternationalObesity 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. Waistcircumference cut-offs of =94cm for males and =80cm for females, and waist-to-height ratio of0.5 for both sexes, were used to determine central obesity and hence metabolic disease risk inixadolescents. Descriptive analysis described patterns of nutritional status by age, sex, pubertalstage and HIV status. Linear and logistic regression was done to determine predictors ofnutrional outcomes. A p-value of <0.05 was considered statistically significant.Results: Prevalence of undernutrition, particularly stunting, was substantial: 18% amongchildren aged 1-4 years, with a peak of 32% in children at one year of age. Stunting andunderweight 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, almostnon-existent in boys, was prominent among adolescent girls, increasing with age, and reaching apeak of 25% at 18 years. Risk for metabolic disease using waist circumference cut-offs wassubstantial among adolescents, particularly girls, increasing with sexual maturation, and reachinga peak of 35% at Tanner stage 5. Prevalence of HIV in children aged 1-4 years was 4.4%. HIVpositive 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, notsignificant. 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 ofoverweight/obesity and risk for metabolic disease in adolescents aged 10-20 years, documented atindividual/child and household levels included child’s age, sex and pubertal development; andhousehold-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 allcaregivers had accepted and valued knowing their child’s HIV status, indicating that it enhancedtheir competency in caregiving. Additionally, nutritional status of HIV positive children hadimproved significantly within a year of follow-up.Conclusions: The study describes co-existing child stunting and adolescent overweight/obesityand risk for metabolic disease in a society undergoing nutrition transition. While likely that thisprofile reflects changes in nutrition and diet, variation in infectious disease burden, physicalactivity patterns, and social influences need to be investigated. The findings are critical in thewake of the rising public health importance of metabolic diseases in low- to middle-incomecountries, despite the unfinished agenda of undernutrition and infectious diseases. Clearly,policies and interventions to address malnutrition in this and other transitional societies need to bedouble-pronged. In addition, gender-biased nutritional patterns call for gender-sensitive policiesand interventions. The study further documents a significant role of paediatric HIV on nutritionalstatus, and the potential for community-based paediatic HIV testing to ameliorate this. Targetedearly paediatric HIV testing of exposed or at risk children, followed by appropriate health care forinfected children, may improve their nutritional status and survival.

[发布机构] University of the Witwatersrand