What are the pathways between poverty and malaria in sub-Saharan Africa? A systematic review of mediation studies

Abstract

Background Malaria remains a major burden in sub-Saharan Africa (SSA). While an association between poverty and malaria has been demonstrated, a clearer understanding of explicit mechanisms through which socioeconomic position (SEP) influences malaria risk is needed to guide the design of more comprehensive interventions for malaria risk mitigation. This systematic review provides an overview of the current evidence on the mediators of socioeconomic disparities in malaria in SSA. Methods We searched PubMed and Web of Science for randomised controlled trials, cohort, case-control and cross-sectional studies published in English between January 1, 2000 to May 31, 2022. Further studies were identified following reviews of reference lists of the studies included. We included studies that either (1) conducted a formal mediation analysis of risk factors on the causal pathway between SEP and malaria infections or (2) adjusted for these potential mediators as confounders on the association between SEP and malaria using standard regression models. At least two independent reviewers appraised the studies, conducted data extraction, and assessed risk of bias. A systematic overview is presented for the included studies. Results We identified 41 articles from 20 countries in SSA for inclusion in the final review. Of these, 30 studies used cross-sectional design, and 26 found socioeconomic inequalities in malaria risk. Three formal mediation analyses showed limited evidence of mediation of food security, housing quality, and previous antimalarial use. Housing, education, insecticide-treated nets, and nutrition were highlighted in the remaining studies as being protective against malaria independent of SEP, suggesting potential for mediation. However, methodological limitations included the use of cross-sectional data, insufficient confounder adjustment, heterogeneity in measuring both SEP and malaria, and generally low or moderate-quality studies. No studies considered exposure mediator interactions or considered identifiability assumptions. Conclusions Few studies have conducted formal mediation analyses to elucidate pathways between SEP and malaria. Findings indicate that food security and housing could be more feasible (structural) intervention targets. Further research using well-designed longitudinal studies and improved analysis would illuminate the current sparse evidence into the pathways between SEP and malaria and adduce evidence for more potential targets for effective intervention. Graphical Abstract

High prevalence and risk of malaria among asymptomatic individuals from villages with high prevalence of artemisinin partial resistance in Kyerwa district of Kagera region, north-western Tanzania

“…In previous studies, it was also shown that low SES was an important risk factor for malaria infections [ 45 , 58 – 60 ], mainly due to the strong association between malaria and poverty [ 61 , 62 ]. Poor people have a higher risk of malaria infections because they cannot afford the cost of malaria prevention and/or treatment and they lack and/or possess a low level of knowledge and skills required to protect themselves against malaria infections [ 63 ].…”

Adherence to HIV Treatment among Children and Adolescents in Selected Nigerian States: Gaps and Lessons

“…For instance, poverty which was identified as a keyfactors for non-adherence to HIV treatment had also been cited in the literature on several other health conditions in sub-Saharan Africa as inhibitory especially as it relates to procurement of drugs and cost of transportation to facilities. In the case of malaria for instance, poverty has been linked to inadequate housing, low education, poor nutrition and non-use of insecticide treated nets among others (Wafula, Habermann, Franke, May, Puradiredja et al, 2023). However, the unique thing about nonadherence to HIV medication is the danger of relapsing and loss of the gains made in viral suppression over time.…”