DECOMPOSITION OF CHANGES IN MALARIA PREVALENCE AMONG UNDER-FIVE CHILDREN IN NIGERIA

Abstract

Malaria among under-five children remains a public health problem in sub-Saharan Africa. Insecticide-treated mosquito net (ITN) used for protection against mosquito bites have proven to be a practical, highly effective, and cost-effective intervention against malaria. Despite the fact that ITN have been made accessible to the population, malaria still continues to be the major cause of child mortality and morbidity in Nigeria. Although, several studies have assessed the utilization of ITN, its impact on the prevalence of malaria over time is yet to be documented in Nigeria. Therefore, this study was conducted to decompose changes in malaria prevalence among underfive children between 2003 and 2013. The data for this study were extracted from the children recode file of the 2003 and 2013 Nigeria Demographic Health Survey (NDHS) datasets. The outcome variable was the occurrence of malaria in which occurrence of fever was used as a proxy, while explanatory variables include child's age, child's sex, place of residence, maternal education, wealth index, ownership of ITN and utilization of lTN. Malaria prevalence and its determinants in 2003 and 2013 were summarized using frequency and percentages. Percentage change in both outcome and explanatory variables between 2003 and 2013 was estimated. Logistic regression was used to explore factors associated with malaria among children under five. A multivariate decomposition technique was used to partition changes in malaria prevalence into two components- contribution of changes in determinants and changes in the effect of determinants. A total of 5204 and 28634 records of children under-five were available in 2003 and 2013 respectively for analysis. Malaria prevalence decline by 59% between 2003 and 2013. Ownership of ITN increased by 383% and the utilization of ITN increased b y 221 % between the two periods. Child's age, maternal education, wealth index were found lo be associated with malaria, ownership of ITN (OR = 1.19; 95% Cl = l.1002. 1.2795), utilization of ITN (OR= 0.99; 95% CI= 0.9193. 1.0862), Oaxaca blinder decomposition analysis showed a difference of 0.1879 (p <0.001) in the prevalence of malaria between the two years. Changes in determinants contributed 4.7% and changes in the effect of determinants contributed 95.3% in the decline of malaria prevalence. Ownership of ITN and its utilization contributed 92% and 13.3% to the observed decline of malaria. There was a decline in the prevalence of malaria among children under five in Nigeria in the last ten years. Ownership of ITN and its utilization were the most contributing factors to the decline in the prevalence of malaria. Mother's level of education should be enhanced, more efforts should be made in promoting ITN and its utilization should therefore continue.