Clustering of mortality among children under five years due to malaria at the Ifakara demographic surveillance site in Tanzania
Date
2009-04-28T13:20:00Z
Authors
Kamara, Mohamed Koblo
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Abstract
ABSTRACT
Introduction
Under-five mortality is still a major cause of concern in Sub Saharan Africa and among
the highest in the world. This is also exacerbated by the high prevalence and episodes of
malaria in this age group, which accounts for 90% of all under-five deaths estimated in
the region annually. The effect of detecting clustering of all cause and cause specific
mortality and underlying factors is crucial for timely public health interventions. This is
especially important for health authorities in Tanzania where under-five malaria
attributable deaths accounts for 45% of the annual estimated mortality of 100, 000.
Study objectives
To estimate under-five mortality and analyze clustering of all cause and malaria specific
mortality among under five children in Ifakara Demographic Surveillance System from
2002-2005.
Methods
Data from the Ifakara Health Research and Development Centre (IHRDC) were obtained
for all under-five children who lived in 25 villages in the DSS from 2002 – 2005.
Analyses for all cause and malaria cause specific under-five mortality were done using
data collected from the DSS and verbal autopsy systems. Annual all cause and malaria
specific mortality rates were calculated by dividing number of deaths and person years
observed. Clustering of deaths for all cause and cause specific (malaria) in the 25 villages
were analyzed using SaTScanTM version 7.0 software. A Poisson model was used to detect
clusters with high rates in space and in space-time. Household assets and characteristics
were used to construct a wealth index using Principal component analysis (PCA) in
StataTM version9. The index was used to group households into five equal groups from
poorest to least poor.
Results
Overall infants’ mortality was sixty-three times higher (326 per 1,000 person years)
compared to children (5.1 per 1,000 person years) and with mortality rates between girls
and boys were very similar, (15.8 and 14.8 per 1,000 person years). Year of death and
place of death (village) were found to be significantly associated with malaria deaths.
However, socio-economic status of parents in households where deaths occurred was not
associated to malaria deaths in the DSS. A number of statistically significant clusters of
all cause and cause specific malaria deaths were identified in several locations in the
DSS. The located clusters imply that villages within the clusters have an elevated risk of
under-five deaths. A space-time cluster of four villages with radius of 15.91 km was
discovered with the highest risk (RR 2.71; P-value 0.020) of malaria deaths in 2004.
Conclusion
These findings demonstrate that there is non-random clustering of both all cause and
malaria cause specific mortality in the study area. The high infant mortality results also
suggest a careful examination of the data collection procedures in the DSS and require
further studies to understand this pattern of mortality among the under-five population.
Appropriate health interventions aimed at reducing burden of malaria should be
strengthened in this part of rural Tanzania. There is need to replicate this study to other
areas in the country.
Description
Keywords
malaria, children, mortality, Ifakara, Tanzania