Understanding the malaria-poverty vicious circle

说明(申请人提供)：了解疟疾-贫困恶性循环6.项目摘要/摘要这项研究的长期目标是：(A)制定一个概念框架，以了解疟疾与贫困之间潜在的双向因果关系；(B)对拟议的概念框架进行实证测试；(C)就疟疾与社会经济地位之间的双重关系提供证据；(D)设计新的调查工具，便利衡量拟议概念框架所包含但尚未纳入标准调查的机制；以及(E)评估成功的疟疾控制干预措施的经济影响。作为实现这些长期目标的第一步，R21应用的目标是开发对疟疾-贫困双向因果关系的分析性和经验性评估。我们将基于对影响疟疾与贫困之间联系的因素的文献审查，提出一个概念框架，并将通过提出这些联系在多个空间尺度上的可能变化来增加一层复杂性。该框架建立在对疟疾的系统看法的基础上；它将允许复制研究并促进研究结果的比较。经验模型将基于联立方程系统，并将利用坦桑尼亚、卢旺达和安哥拉的人口和健康调查(DHS)数据。我们将使用带有工具变量的两阶段最小二乘法来估计模型。疟疾将通过寄生虫血症(通过显微镜测量)来量化，减少在将发烧视为疟疾代用品的研究中观察到的潜在偏差。SES将由基于家庭拥有耐用资产和住房条件的财富指数来衡量。评估疟疾对SES影响的工具包括怀孕状况、海拔高度和降雨量；评估SES对疟疾影响的工具包括性别和种族；距主要城镇的距离；以及农业季节的总降雨量(S)。我们将使用Sargan‘s检验对工具的有效性进行统计测试，以确定过度识别限制。根据工具的适用性，我们可能需要使用其他方法进行因果分析(例如，倾向得分匹配)。我们选择坦桑尼亚、卢旺达和安哥拉，是因为国土安全部最近的调查包括通过显微镜进行疟疾寄生虫测试，减少了将发烧视为疟疾代用品的研究中观察到的潜在偏差。国土安全部是具有全国代表性的调查，因此包括不同的环境：城市和农村，疟疾风险低和高，贫穷和相对富裕；它们还包含允许评估空间差异的地理信息，有助于确定疟疾控制干预措施的目标。我们的分析和经验模型将使我们能够评估正在进行的显著降低疟疾发病率的控制干预措施的经济影响，这是当前消除疟疾目标的研究重点。公共卫生相关性：拟议的研究将提供一个框架，以加强对疟疾-贫困双向因果关系的科学调查，促进跨国比较。它有可能使疟疾流行国家更好地选择和瞄准既能减轻疟疾负担又能促进减贫的干预措施。这项研究还将为评估不同国家疟疾控制努力的经济影响奠定基础，这是实现当前消除疟疾目标的研究重点。

DESCRIPTION (provided by applicant): Understanding the malaria-poverty vicious circle 6. Project Summary/Abstract The long-term goals of this research are (a) to develop a conceptual framework for understanding the potential bi-directional malaria-poverty causality; (b) to empirically test the proposed conceptual framework; (c) to provide evidence regarding the magnitude of the dual relationship between malaria and socioeconomic status (SES); (d) to design new survey instruments that facilitate the measurement of mechanisms included in the proposed conceptual framework but not yet available in standard surveys; and (e) to evaluate the economic impacts of successful malaria control interventions. As a first step toward these long-term goals, the objectives of this R21 application are to develop analytical and empirical assessments of the bi-directional malaria- poverty causality. We will propose a conceptual framework based on literature review of factors that impact the links between malaria and poverty, and we will add a layer of complexity by proposing possible variations of these links at multiple spatial scales. The framework builds upon a systemic view of malaria; it will allow for study replication and facilitate comparison of findings. The empirical model will be based on a system of simultaneous equations and will utilize Demographic and Health Surveys (DHS) data for Tanzania, Rwanda, and Angola. We will estimate the model using two-stage least squares with instrumental variables. Malaria will be quantified by parasitaemia (as measured by microscopy), reducing the potential bias observed in studies that considered fever as a proxy for malaria. SES will be measured by a wealth index based on household ownership of durable assets and on housing conditions. Instruments for estimating the effect of malaria on SES include pregnancy status, elevation, and precipitation; instruments for estimating the effect of SES on malaria include gender and ethnicity; distance to major towns; and total rainfall during the agricultural season(s). We will conduct statistical tests of instrument validity using a Sargan's test for over-identifying restrictions. Depending on the suitability of the instruments, we may need to use other methods for causal analysis (e.g. propensity score matching). We choose Tanzania, Rwanda, and Angola because recent DHS surveys included malaria parasite testing by microscopy, reducing the potential bias observed in studies that consider fever as a proxy for malaria. The DHS are nationally representative surveys and therefore comprise diverse settings: urban and rural, low and high malaria risk, poor and relatively wealthy; they also contain geographical information that allows for the assessment of spatial variations, facilitating the targeting of malaria control interventions. Our analytical and empirical models will allow for the evaluation of economic impacts of on- going control interventions that significantly reduced malaria incidence, which is a research priority for the current goals of malaria elimination. PUBLIC HEALTH RELEVANCE: proposed study will provide a framework for increased scientific investigation of the bi-directional malaria-poverty causality, facilitating cross-country comparisons. It has the potential to allow malaria-endemic countries to better select and target interventions that both reduce the malaria burden and promote poverty alleviation. The research will also prepare the way to assess the economic impact of malaria control efforts in different countries, a research priority toward current malaria elimination goals.