Bayesian random effects modelling with application to childhood anaemia in Malawi.

Alfred Ngwira,Lawrence N Kazembe

doi:10.1186/s12889-015-1494-y

Alfred Ngwira, Lawrence N Kazembe

Open Access

https://doi.org/10.1186/s12889-015-1494-y

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Abstract

BackgroundEpidemiological studies in Malawi on child anaemia have neglected the community spatial effect to childhood anaemia. Neglecting the community spatial effect in the model ignores the influence of unobserved or unmeasured contextual variables, and at the same time the resultant model may under estimate model parameter standard errors which can result in erroneous significance of covariates. We aimed at investigating risk factors of childhood anaemia in Malawi with focus on geographical spatial effect.MethodsWe adopted a Bayesian random effect model for child anaemia with district as spatial effect using the 2010 Malawi demographic healthy survey data. We fitted the binary logistic model for the two categories outcome (anaemia (Hb < 11), and no anaemia (Hb ≥ 11)). Continuous covariates were modelled by the penalized splines and spatial effects were smoothed by the two dimensional spline.ResultsResidual spatial patterns reveal Nsanje, Chikhwawa, Salima, Nkhota-kota, Mangochi and Machinga increasing the risk of childhood anaemia. Karonga, Chitipa, Rumphi, Mzimba, Ntchisi, and Chiradzulu reduce the risk of childhood anaemia. Known determinants such as maternal anaemia, child stunting, and child fever, have a positive effect on child anaemia. Furthermore childhood anaemia decreases with child age. It also decreases with wealth index. There is a U relationship between child anaemia and mother age.ConclusionStrategies in childhood anaemia control should be tailored to local conditions, taking into account the specific etiology and prevalence of anaemia.

Highlights

Epidemiological studies in Malawi on child anaemia have neglected the community spatial effect to childhood anaemia
Childhood anaemia prevalence increases with cough and fever
Childhood anaemia prevalence increases with childhood under nutrition

Summary

Introduction

Epidemiological studies in Malawi on child anaemia have neglected the community spatial effect to childhood anaemia. According to World Health Organization (WHO) current report on world prevalence of anaemia [1], the global prevalence of anaemia is 24.8% with the highest prevalence in preschool-age children (47.4%). The latest report though by [2] on world prevalence of anaemia shows that world prevalence of anaemia for preschool-age children has decreased from 47% to 43% and that South Asia, Central and West Africa have the highest prevalence. About 50% of all anaemia cases are due to iron deficiency [6] Other micronutrients, such as vitamin A, vitamin C, and folate are important in the pathophysiology of anaemia. Sickle cell disease has been recognized as an important risk factor for anaemia in subSaharan countries [12]

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