Department of Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Department of Disease Control and Environmental Health, School of Public Health, Makerere University, Kampala, Uganda.
Infect Dis Poverty. 2023 Jun 8;12(1):58. doi: 10.1186/s40249-023-01110-2.
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.
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.
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.
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.
疟疾在撒哈拉以南非洲（SSA）仍然是一个主要负担。虽然已经证明贫困与疟疾之间存在关联，但需要更清楚地了解社会经济地位（SEP）影响疟疾风险的明确机制，以便为减轻疟疾风险设计更全面的干预措施提供指导。本系统评价概述了目前关于 SSA 中疟疾与社会经济差异相关因素的证据。
我们在 PubMed 和 Web of Science 中搜索了 2000 年 1 月 1 日至 2022 年 5 月 31 日期间以英文发表的随机对照试验、队列研究、病例对照研究和横断面研究。通过对纳入研究的参考文献进行回顾，进一步确定了其他研究。我们纳入了以下两种研究：（1）对 SEP 与疟疾感染之间因果关系路径上的危险因素进行正式中介分析；或（2）使用标准回归模型将这些潜在中介物作为 SEP 与疟疾之间关联的混杂因素进行调整。至少有两名独立评审员对研究进行评估、数据提取和偏倚风险评估。对纳入的研究进行了系统综述。
我们从 SSA 的 20 个国家确定了 41 篇文章纳入最终综述。其中，30 项研究采用横断面设计，26 项研究发现疟疾风险存在社会经济不平等。三项正式的中介分析显示，粮食安全、住房质量和以往抗疟药物使用的中介作用证据有限。其余研究强调了住房、教育、驱虫蚊帐和营养对疟疾的保护作用，独立于 SEP，表明可能存在中介作用。然而，方法学上的局限性包括使用横断面数据、混杂因素调整不足、SE 和疟疾的测量存在异质性以及研究总体质量较低或中等。没有研究考虑暴露中介物相互作用或可识别性假设。
很少有研究进行正式的中介分析来阐明 SEP 与疟疾之间的途径。研究结果表明，粮食安全和住房可能是更可行的（结构性）干预目标。使用设计良好的纵向研究和改进的分析的进一步研究将阐明 SEP 与疟疾之间目前证据稀疏的途径，并为更有效的干预措施提供更多潜在目标的证据。
