Statistical modelling on childhood anaemia, malaria and stunting in Malawi, Lesotho, and Burundi.
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Date
2023
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Abstract
The current research aimed to produce and expand statistical models in the discipline of
biostatistics with a focus on childhood anaemia, malaria, and stunting. Malaria, anaemia, and
stunting together continue to be public health issues worldwide in both industrialised and
underdeveloped countries, particularly in children younger than 5 years (Osazuwa and Ayo,
2010; Kanchana et al., 2018). Malaria, anaemia, and stunting are dangerous, mostly in children
from underdeveloped nations and they still remain the biggest contributor to morbidity and
mortality. In addition, anaemia, malaria, and stunting are associated, and if not treated on time
can damage children’s emotional, physical, mental status and poor performance at school
(Gaston et al., 2022). The current study evaluates the link between anaemia, stunting, and
malaria simultaneously. Furthermore, the study assessed whether socioeconomic,
geographical, environmental, and child demographic variables have a significant effect on
childhood malaria, anaemia, and stunting. This study used a national secondary cross-sectional
data from Malawi Malaria Indicator Survey (MMIS); Lesotho Demographic Health Survey
(LDHS); and Burundi Demographic Health Survey (BDHS). The data was collected based on
multi-stage sampling, stratified, and cluster sampling with an unequal chance of sampling. It
is for this reason we first used the survey logistic regression model in Chapter 3, which
accounted for the complexity of sampling design and heterogeneity between observations from
the same cluster. However, this model includes only the fixed effect and does not have the
option of adding the random effect to model the correlation between observations. We extend
the model in Chapter 4, to a generalised mixed additive model (GAMM) to include the random
effect. The GAMM is also an extension of the generalised linear mixed model (GLMM) and
enables the parametric fixed effects from GLMM to be modelled as a non-parametric model
using the additive smooth function. These models were applied to single response variables,
and we wanted to evaluate the relationship which might exist between anaemia, stunting, and
malaria. We then explore the multivariate joint model under GLMM in Chapter 5 to
simultaneously joint either malaria and anaemia or anaemia and stunting. Finally, we introduce
a structural equation model (SEM) in Chapter 6, to evaluate the complex interrelationships
between socioeconomics, demographics, and environmental factors, as well as their direct or
indirect relationship with childhood malaria, anaemia and stunting co-morbidity. The previous
chapters could not address these interrelationships among the variables of interest. Each model
used in this study has its weaknesses and strengths which can depend on the goal of the researcher. However, the multivariate model under GLMM and the structural equation model
were found to be more adaptive and attractive to researchers interested in innovative scientific
research.
The findings from this study revealed that the child’s nutrition status, age, the child with fever,
diarrhoea, altitude, place of residence, toilet facility, access to electricity, children who slept
under a mosquito bed net the night before the survey, mother's education level, and mother’s
body mass index have a significant effect on both childhood anaemia and malaria. The age of
a child, the mother’s educational status, place of residence, wealth index, and child weight at
birth were the determinants of stunting or malnutrition. The findings also indicated that the
geographical, geophysical, environmental, household and child demographic factors were
statistically significant and have either a direct or an indirect effect on childhood co-morbidity
factors. The geographical factors were statistically significant and had a positive direct effect
on childhood malaria, anaemia, and stunting. The estimated indirect path for the impact of
geophysical factors on childhood co-morbidity factors, as mediated by household factors was
statistically significant and positive. However, the estimated indirect paths for the effect of
geophysical factors on childhood co-morbidity factors, as mediated by environmental factors
were statistically significant but negative.
The child demographic factors revealed a direct statistically significant impact on childhood
co-morbidity factors. Furthermore, the estimated indirect path effect on childhood comorbidity
as mediated effect on household factors was statistically significant and negative.
Moreover, household and environmental factors indicate a positive direct effect on childhood
co-morbidity anaemia, malaria, and stunting. Finally, the results of this study revealed a
positive relationship between stunting, anaemia, and malaria. This means that malaria,
anaemia, and stunting increase or decrease in the same direction. Hence, controlling one or two
between malaria, anaemia, and stunting can reduce the effect of other(s), which can assist the
policymakers and government in the allocation of financial resources to fight against childhood
comorbidity anaemia, malaria, and stunting. Furthermore, understanding the link between
anaemia, malaria, and stunting other factors associated with them will assist in focusing on
those areas and go a long way toward achieving the United Nations Sustainable Development
Goals (SDGs3), known as the complete elimination of under-5 mortality by 2030.
Description
Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.