Decomposition of changes in malaria prevalence amongst under-five children in Nigeria.

Background: Malaria remains a major public health problem in Nigeria. Changes in malaria prevalence can be attributed to three major control interventions: insecticide treated nets (ITNs), indoor residual spraying (IRS) and intermittent preventive treatment in pregnancy (IPTp). Use of ITNs has proven to be a practical, highly effective, and cost-effective intervention against malaria. Although, several studies have assessed the utilisation of ITNs, 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 amongst under-five children between 2003 and 2013.

Materials and methods: A retrospective analysis of the 2003 and 2013 Nigeria Demographic Health Survey (NDHS) dataset was conducted. Occurrence of fever was used as a proxy for malaria. Percentage change in both outcome and explanatory variables between 2003 and 2013 was estimated. 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.

Results: A total of 5204 and 28634 records of children under-five were available in 2003 and 2013 respectively. Malaria prevalence declined from 31.8% to 13.1% between 2003 and 2013 (p<0.001). Changes in determinants contributed 4.7% and changes in the effect of determinants contributed 95.3% to the change in malaria prevalence.

Conclusions: There was a decline in the prevalence of malaria amongst children under five in Nigeria in the last ten years. Ownership of ITNs and their utilisation were the most contributing factors to the decline in malaria prevalence. Continued efforts should be made in promoting ITNs and their consistent and appropriate utilisation.