Articles included in the review.

BackgroundPodoconiosis is a non-infectious neglected tropical disease that causes progressive swelling of the lower limbs in an estimated 4 million people globally. Podoconiosis has been associated with prolonged exposure to certain soils, however no specific causative component has been identified. We conducted a systematic review of articles to investigate links between podoconiosis and mineral, geochemical and climate factors affecting soil genesis (pedogenesis).Methodology/principal findingsA systematic search was conducted across five electronic databases: Embase, Global Health, Medline, GeoRef and Web of Science. Searches were from database inception to January 2024. Primary quantitative research from any region was included, qualitative studies and those not in English were excluded. The AXIS tool was used to assess study quality and risk of bias. Twenty-seven studies were included and narrative synthesis was used to interpret data from tissue samples, soil samples, and remote sensed bedrock and pedogenic factors. Nine studies found a correlation between podoconiosis occurrence and regions with underlying alkalic volcanic bedrock, and six linked pedogenic factors (altitude and rainfall) with disease occurrence. Several studies linked specific soil mineralogy and geochemistry with endemic regions, including an abundance of phyllosilicate clay minerals, quartz, and trace elements, notably iron, beryllium and zirconium.ConclusionsThis systematic review is the first to be conducted on the literature linking pedogenic factors with podoconiosis globally. Study quality was low for some of the earlier (1970s) studies. Several soil mineralogical and geological variables were linked with podoconiosis prevalence, particularly kaolinite, smectite, micas, quartz, iron oxides and trace elements. However, it remains unclear whether these are covariates or direct contributors to the pathogenesis of the disease and what the role of other peculiarities of soils (complex mineral-organic or material-climate combined factors) might be. Studies on the enrichment of minerals and elements during pedogenesis should be prioritised in future research.Protocol registrationPROSPERO International prospective register of systematic reviews registration number CRD42024499266.背景 脚癣病（Podoconiosis）是一种非感染性被忽视的热带病，全球估计有400万患者出现下肢进行性肿胀。该病与长期接触特定土壤存在关联，但尚未明确其具体致病成分。本研究对相关文献开展系统综述，旨在探究脚癣病与影响土壤形成（成土作用，pedogenesis）的矿物、地球化学及气候因素之间的关联。 研究方法/主要结果 本研究在Embase、Global Health、Medline、GeoRef及Web of Science共5个电子数据库中开展系统检索，检索时限为数据库建库至2024年1月。纳入所有地区的定量原始研究，排除定性研究及非英文文献。采用AXIS工具评估研究质量与偏倚风险。最终纳入27项研究，通过叙述性综合分析解读组织样本、土壤样本、遥感基岩及成土因素相关数据。9项研究发现脚癣病的发生与下伏碱性火山基岩的区域存在相关性；另有6项研究指出成土因素（海拔与降雨量）与疾病发生存在关联。多项研究将特定土壤矿物学与地球化学特征与流行区域联系起来，包括丰富的层状硅酸盐黏土矿物、石英及微量元素（尤其是铁、铍与锆）。 结论 本系统综述是全球范围内首项针对成土因素与脚癣病关联的相关文献综述。部分早期（1970年代）研究的质量较低。多项土壤矿物学与地质学特征与脚癣病患病率存在关联，尤其是高岭石、蒙脱石、云母、石英、氧化铁及微量元素。但目前仍无法明确这些因素是疾病发病机制的混杂因素还是直接致病因素，也不清楚土壤的其他特性（如复杂的矿物-有机质或物质-气候复合因素）所发挥的作用。未来研究应优先关注成土过程中矿物与元素的富集机制。 方案注册 本研究已在国际系统综述前瞻性注册平台PROSPERO完成注册，注册编号为CRD42024499266。