ETD Collection

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Author: search.filters.author.Crowther, Penny

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    The association between household food security and mortality in children under-five years of age in Agincourt, Limpopo Province, in 2004
    (2008-10-24T09:05:56Z) Crowther, Penny
    Background: When children experience food insecurity, in addition to poverty, their resultant inadequate food intake and disease often leads to the development of proteinenergy malnutrition and ultimately to death. In South Africa, where three out of every four children live in poverty, food insecurity and its multiple negative effects are consequently among the most urgent social issues affecting households and their children. Since household food insecurity is thought to be associated with increased child mortality, it is important to study any such associations amongst South African children to determine additional risk factors for child mortality. Objectives: The main objective of this study was to establish the relationship between household food security and mortality in children under the age of five years in the Agincourt field site, Limpopo Province, in 2004. Methods: An analytical cross-sectional study of secondary data obtained from the 2004 census questionnaire and food security module of the Agincourt Health and Demographic Surveillance System in rural Limpopo Province was conducted, involving a total of 7,790 black children under the age of five years. Certain exposure variables were selected for use as indicators of food security and these were analysed with respect to child mortality using univariate and multivariate logistic regression. Results: Based on the outcome indicators of food consumption, 37% of the study population were found to have experienced household food insecurity in 2004, reporting insufficient food for the entire household in the previous month and year. The limited dietary diversity and insufficient quantities of food experienced by the majority of the population were supplemented by the local growth of food crops and the gathering of food from the bush. Of the 79 children (1%) under the age of five years who died in 2004, the majority (24%) died of HIV-related diseases, in addition to deaths caused by diarrhoea, respiratory infections, and malnutrition. Child mortality was found to be associated with the reporting of “unknown” for several indicators of food security. Additionally, expecting the food availability of the household in the coming year to be less than that of the current year (that is, the prediction of future household food insecurity) was significantly associated with an increased risk of under-five child mortality compared to the expectation of the same amount of food the following year (adjusted odds ratio (OR) 2.0), and with a greatly increased risk of mortality compared to the prediction of more food (future household food security) (adjusted OR 4.4). The latter association was age-specific to infants under the age of one year (adjusted OR 5.6) and cause-specific to HIV deaths (adjusted OR 5.9). Conclusions: Following a significant trend in this study in the rural north-east of South Africa, future household food security was inversely related to, and hence protective over, childhood mortality in 2004, even after controlling for confounding factors. Further research on the associations between household food security and under-five child mortality, conducted following the development of a standard nation-wide food security measurement tool specific to South African household conditions, would confirm household food insecurity as a significant risk factor for under-five child mortality and, consequently, as a target for future policies in the reduction of child mortality in this country.
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    Molecular characterisation of Hepatitis B virus vaccine escape mutants in South Africa
    (2006-11-17T12:51:16Z) Crowther, Penny
    Since the introduction of vaccination against hepatitis B virus (HBV) infection in South Africa, at least one case of infection despite vaccination has occurred. The purpose of this study was to determine whether this infection was the result of mutations within the region of the surface (S) gene encoding the a determinant epitopes of the hepatitis B surface antigen, which permitted viral vaccine-escape. HBV DNA was extracted from the serum and liver tissue of the patient and amplified within the complete 3 215 bp genome and S gene, respectively. Following cloning, sequencing revealed a minor population displaying unique or uncommon S gene mutations that resulted in C138R, C139R, K141R, P142L, T143A, N146D, and T148A amino acid substitutions in the clones from the serum, and C139Y and D144N in the clones from the liver. Such isolates may represent South African HBV vaccine-escape mutants that caused chronic infection in the host prior to their reversion to wild-type.